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Effect of chitin on antagonistic activity of Cryptococcus laurentii against Penicillium expansum in pear fruit
Abstract
This study was designed to evaluate the impact of chitin on the antagonistic activity of Cryptococcus laurentii against the postharvest blue mold rot caused by Penicillium expansum in pear fruit. The results showed that the antagonistic activity of C. laurentii obtained from the culture media of nutrient yeast dextrose broth (NYDB) amended with chitin at 0.5-1.0% was improved greatly compared with the case that without chitin. The addition of chitin to NYDB did not influence the growth of C. laurentii, however, its population was found to increase rapidly thereafter in pear fruit wounds compared to that harvested from NYDB without chitin. Moreover, the cell-free filtrate of the chitin-supplement culture media in which the yeast was incubated for 24 h emerged a direct antifungal activity against P. expansum in pear fruit wounds, with the associated high level of chitinase activity. These results suggested that the use of chitin may be an effective method to induce the antagonistic activity of C. laurentii. To our knowledge, this is the first report regarding the chitin could enhance the efficacy of postharvest biocontrol yeasts.
... A limited number of studies have suggested that natural compounds, such as chitin and chitosan, may have agriculturally useful synergisms when applied with a BCA [17,34]. There are several hypotheses regarding the mechanisms behind these synergisms including a heightened plant defense response [35], enhanced BCA population growth [15], and increased chitinase production by BCAs [36]. For example, Baciullus pumilus (PGPR strain SE 34) combined with chitosan resulted in an amplified defense response on tomatoes infected with Fusarium oxysporum f. sp. ...
... The chitosan product may have washed off before it was able to provide a food source for the BCA or stimulate antimicrobial enzymes. Very few studies have examined the co-application of chitosan and a BCA under field conditions [17,[34][35][36]. Kokalis-Burelle et al. found that the co-application of reagent grade chitin and B. cereus along with a spreader-sticker (SoyDex) enhanced disease suppression, likely due to improved foliar colonization of the BCA [15]. ...
The natural product chitosan has been shown to reduce plant disease severity and enhance the efficacy of microbial biocontrol agents in several crops. However, little is known about the potential synergisms between chitosan and biopesticides and best use practices in apple production. The objectives of this study were to evaluate the effect of pre-harvest applications of chitosan alone and in combination with a commercial biopesticide to suppress fungal diseases of apple and to investigate the potential for chitosan to reduce the quantity of overwintering Venturia inaequalis spores in orchard leaf litter. Chitosan products, Tidal Grow and ARMOUR-Zen 15, and a commercial biopesticide, Serenade ASO, were tested in a research orchard in Pennsylvania and commercial orchards in New Hampshire. Chitosan applications reduced apple scab incidence and severity by up to 55% on fruit compared to the water control. Chitosan also reduced sooty blotch, flyspeck, and rust incidence on fruit. Furthermore, a chitosan + biopesticide treatment overlayed onto a grower standard spray program reduced diseases more effectively than the grower standard alone. However, this efficacy was dependent on the cultivar and pathogen. Chitosan did not reduce overwintering V. inaequalis ascospores. This research provides evidence that pre-harvest chitosan applications have the potential for disease management in apple production.
... et Pseudomonas spp. sont considérés comme des antagonistes plus efficaces des pathogènes fongiques en raison de l'action directe de la chitinase seule (Yu et al. 2008). Les chitinases hydrolysent la chitine, la N-acétylglucosamine homopolymère non ramifiée dans une liaison 1,4 par deux mécanismes possibles : (1) l'exo-chitinase ou la N-Acétyl-b-glucosaminidase, qui segmente séquentiellement les résidus extrêmes NAG ; et (2) l'endo-chitinase, qui active les liaisons dans des sites aléatoires le long de la chaîne polymère (Stoykov, 2015). ...
... Au cours de la dernière décennie, différentes recherches ont été réalisées sur les enzymes hydrolytiques produisant des bactéries et des levures(Ait Bahadou et al. 2018). Les genres Bacillus et Pseudomonas sont considérés comme certains des antagonistes les plus efficaces dans le contrôle des phytopathogènes en raison de l'action directe de la chitinase(Yu et al, 2008). Shivakumar et al (2014), ont réalisé une purification partielle, une caractérisation et des études cinétiques de l'enzyme chitinase de la bactérie Bacillus subtilis JN032305, dans lesquelles l'enzyme partiellement purifiée a non seulement montré une activité antifongique contre Rhizoctonia solani et Colletotrichum gloeosporioides, mais a également augmenté la germination des graines de poivre lorsqu'elles ont été infectées par les champignons mentionné. ...
... Chitosan has also used as a promising postharvest treatment for fruits due to its natural character, antimicrobial activity and elicitation of defense responses (Katiyar et al., 2014) [28] . Chitosan has been used to control postharvest diseases of many fruits such as pear (Yu et al., 2008) [68] , strawberry (Ge et al., 2010) [14] , table grape (Meng et al., 2008), tomato (Badawya and Rabeab 2009) [2] , citrus and longan (Jiang and Li 2001) [25] . Chitosan is one of the most important elicitors. ...
... Chitosan has also used as a promising postharvest treatment for fruits due to its natural character, antimicrobial activity and elicitation of defense responses (Katiyar et al., 2014) [28] . Chitosan has been used to control postharvest diseases of many fruits such as pear (Yu et al., 2008) [68] , strawberry (Ge et al., 2010) [14] , table grape (Meng et al., 2008), tomato (Badawya and Rabeab 2009) [2] , citrus and longan (Jiang and Li 2001) [25] . Chitosan is one of the most important elicitors. ...
Chitosan has received much interest for potential wide application in agriculture due to its excellent biocompatibility, biodegradability and bioactivity. Chitosan is, a linear polysaccharide composed of randomly distributed b-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit) is an environmental friendly product. Chitin can be easily obtained from shellfish waste. The chitosan molecule triggers defense responses within the plant, leading to the formation of physical and chemical barriers against invading pathogens. Chitosan has been used to stimulate the immunity of plants to protect plants against microorganisms. This protection leads stimulation of plant growth. Chitosan affects various physiological responses like plant immunity, defense mechanisms involving various enzymes such as, phenylalanine ammonium lyase, polyphenol oxidase, tyrosine ammonia lyase and antioxidant enzymes viz., activities superoxide dismutase, catalase and peroxide against adverse conditions. Recent studies have shown that chitosan induces mechanisms in plants against various biotic (fungi, bacteria, and insects) and abiotic (salinity, drought, heavy metal and cold) stresses and helps in formation of barriers that enhances plant's productivity. Chitosan has also used as a promising postharvest treatment for fruits due to its natural character, antimicrobial activity and elicitation of defense responses. It has also been shown that chitosan promotes vegetative growth and enhances various processes in developing flower buds. Chitosan treatment have been reported that chitosan increased shoot length, root length, shoot dry weight and relative water content under salinity stress.
... Chitosan has also used as a promising postharvest treatment for fruits due to its natural character, antimicrobial activity and elicitation of defense responses (Katiyar et al., 2014) [28] . Chitosan has been used to control postharvest diseases of many fruits such as pear (Yu et al., 2008) [68] , strawberry (Ge et al., 2010) [14] , table grape (Meng et al., 2008), tomato (Badawya and Rabeab 2009) [2] , citrus and longan (Jiang and Li 2001) [25] . Chitosan is one of the most important elicitors. ...
... Chitosan has also used as a promising postharvest treatment for fruits due to its natural character, antimicrobial activity and elicitation of defense responses (Katiyar et al., 2014) [28] . Chitosan has been used to control postharvest diseases of many fruits such as pear (Yu et al., 2008) [68] , strawberry (Ge et al., 2010) [14] , table grape (Meng et al., 2008), tomato (Badawya and Rabeab 2009) [2] , citrus and longan (Jiang and Li 2001) [25] . Chitosan is one of the most important elicitors. ...
Chitosan has received much interest for potential wide application in agriculture due to its excellent biocompatibility, biodegradability and bioactivity. Chitosan is, a linear polysaccharide composed of randomly distributed b-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit) is an environmental friendly product. Chitin can be easily obtained from shellfish waste. The chitosan molecule triggers defense responses within the plant, leading to the formation of physical and chemical barriers against invading pathogens. Chitosan has been used to stimulate the immunity of plants to protect plants against microorganisms. This protection leads stimulation of plant growth. Chitosan affects various physiological responses like plant immunity, defense mechanisms involving various enzymes such as, phenylalanine ammonium lyase, polyphenol oxidase, tyrosine ammonia lyase and antioxidant enzymes viz., activities superoxide dismutase, catalase and peroxide against adverse conditions. Recent studies have shown that chitosan induces mechanisms in plants against various biotic (fungi, bacteria, and insects) and abiotic (salinity, drought, heavy metal and cold) stresses and helps in formation of barriers that enhances plant's productivity. Chitosan has also used as a promising postharvest treatment for fruits due to its natural character, antimicrobial activity and elicitation of defense responses. It has also been shown that chitosan promotes vegetative growth and enhances various processes in developing flower buds. Chitosan treatment have been reported that chitosan increased shoot length, root length, shoot dry weight and relative water content under salinity stress.
... Enhancing plant vitality and ability to degrade walls of fungi upon entry [74,75] Fertilizer and biocontrol agent [72,76] Enhancing biocontrol efficiency by addition to plant growth-promoting rhizobacteria [77,78,79] 5. ...
... Biotechnology Chitin affinity chromatography to selectively adsorb chitinase from a fermentation broth [65,81] Affinity matrix (chitosan) for the separation of wheat germ agglutinin [65] Enzyme and whole cell immobilizer [82,35,83] N-acetyl chitobiose production from chitin using commercial hydrolytic enzymes [79] Chitinase and chitosanase production from L. paracasei, Pseudomonas and Streptomyces species [84,85,86,87] Microorganism immobilization for bioremediation of seawater polluted with crude oil [88] Support for biosensors [82] Bioseparation [35,36] ...
... Cell wall hydrolases, such as chitinase, secreted by yeast are one of the major antipathogenic factors against mold fungi. Yu et al. (2008) reported that cell-free filtrate of Cryptococcus laurentii cultured in a chitin amended medium, exhibits a high level of chitinase activity, which has direct antifungal activity against Penicillium expansum in pear fruit wounds. Lu et al. (2014) found that the antioxidant enzyme activity, including catalase (CAT) and superoxide dismutase (SOD), in the treatment group (yeast grown in NYDB + elicitor) was significantly higher than it was in the control group (yeast grown in NYDB alone). ...
... Increased abundance of proteins associated with the degradation of pathogen cell walls. A previous report indicated that the secretion of cell wall hydrolases by antagonistic yeast plays a role in and enhances biocontrol efficacy (Yu et al., 2008). Secretion of chitinase by P. membranaefaciens and Candida guilliermondii was reported to contribute to their ability to control R. stolonifera in peaches (Fan et al., 2002). ...
The biocontrol efficacy of the yeast, Rhodotorula mucilaginosa against postharvest diseases of strawberries can be significantly enhanced by culturing the yeast in a medium containing chitosan. The molecular mechanisms involved in the enhanced biocontrol efficacy of R. mucilaginosa, however, have not been comprehensively explored. Results of the present study indicate that the biocontrol efficacy of the yeast against gray mold (Botrytis cinerea) of strawberry was greatest when the yeast was cultured in a medium containing 0.5% (w:v) chitosan for 24 h before use. Proteomic and bioinformatic analyses revealed that proteins involved in growth and reproduction, energy metabolism, antioxidant response, response to abiotic stress, and degradation of pathogen cell walls were all up-regulated by chitosan resulting in the enhanced antagonistic activity of R. mucilaginosa against B. cinerea. The decrease in ROS accumulation in R. mucilaginosa cultured in a medium containing chitosan was in agreement with the increased abundance of proteins related to antioxidant defense. Key differentially expressed proteins (DEPs) were identified and 12 randomly-selected DEPs were validated by parallel reaction monitoring. The present results provide a theoretical reference for further study of the molecular mechanisms involved in the improvement of biocontrol efficacy of antagonistic yeast by elicitor molecules and also provide a novel approach for improving biological control of postharvest diseases.
... Direct growth regulator/ biostimulant/ Antistress agent 1. Induction by Plant Growth Promoting Rhizobacteria (PGPR) through: (1) nitrogen fixation, (2) degrading cell walls of pathogens by chitinases, and (3) growth regulation through activation of signaling molecules (Maximov et al. 2011); 2. Bio-stimulants are multicomponent products; thus, classification should be based on efficacy testing, without elucidation of a specific mode of action (Yakhin et al. 2017). Antitranspirant, wood and leaf sealant 1. Formation of a barrier minimizing evaporation and preventing the pathogen from invading plant tissues (Hirano et al. 1996;Barber et al. 1989 Seed Treatment 1. Antifungal, antiviral, antibacterial properties of seed treatments and promotion of seed's germination rate and plant growth (Yu et al. 2008). ...
... Chitin has been used for enhancing the antagonistic activity of yeast species Cryptococcus laurentii used against the postharvest blue mold rot caused by Penicillium expansum in pear fruit. The study showed an increase in the activity of the yeast with addition of chitin (Yu et al. 2008). C. laurentii yeast population was found to increase rapidly in pear fruit wounds after chitin treatment, and was likely a major reason for increased biocontrol. ...
Due to strict legislation which governs the use of pesticides, fertilizers and plant growth regulators, there is a demand for organic alternatives. Potential risks for people, possible long-term health effects, and pesticide environmental fate resulted in a widespread societal issue. Because sustainable agriculture interconnects the economically and socially, the use of environmentally sound compounds has become popular. Improving plant growth using natural compounds such as chitin, a carbohydrate chain polymer, and its derivatives is a promising sustainable agriculture strategy. Chitin and its derivatives exhibit a unique mode of action being at the same time safe and non-toxic by nature. They are recognized as promising soil amendments for improving soil quality, induce abiotic and biotic plant stress tolerance, boost defense mechanism of plants against invading microorganisms, elicit the production of secondary metabolites, and protect the safety of edible products. Here, we review beneficial effects of chitin as a fertilizer, soil conditioning agent, plant disease control agent, antitranspirant, ripening retardant, and seed and fruit coating.
... spermicide (112) Agriculture plant elicitor (116) stimulation of chitinase and glucanase production (increased response to pathogen attack) (116) stimulation of chitinase activity in compost (change of bacterial and fungal genetic diversity) (117) antimicrobial (antifungal) agent and biopesticide (118,119) enhancing plant vitality and ability to degrade walls of fungi upon entry (120,121) fertilizer and biocontrol agent (118,122) enhancing biocontrol efficiency by addition to plant growth-promoting rhizobacteria (123)(124)(125) Textile and paper textile fibres (75) paper manufacture (additive) ...
... Biotechnology chitin affinity chromatography to selectively adsorb chitinase from a fermentation broth (112,126) affinity matrix (chitosan) for the separation of wheat germ agglutinin (112) enzyme and whole cell immobilizer (41, 90,127) N-acetyl chitobiose production from chitin using commercial hydrolytic enzymes (125) Chitinase and chitosanase production from L. paracasei, Pseudomonas and Streptomyces species (128)(129)(130)(131) microorganism immobilization for bioremediation of seawater polluted with crude oil (79) support for biosensors (41) bioseparation (90,91) Cosmetic ingredients for hair and skin care (moisturizer) (112) ...
This study was devoted to polysaccharides extraction (Chitin and Chitosan) from Penicillium camembertii cell wall. A culture on solid medium was adopted under carefully selected conditions, appropriate to mycelium growth duration 6 days, medium YPGA and pH 5. The temperature was adjusted (20 °C to 28 °C) in order to study the effect of temperature on Chitin/Chitosan production. Biomass decreased with increasing temperatures 13 g/L at 20 °C and 11.6 g/L at 28 °C. For all tested temperatures, the yields of insoluble alkaline fractions (AIM) were almost identical (200 mg/g). The solubility of fractions in 2% acetic acid allowed obtaining two fractions an insoluble fraction (AcIM) with 18% of maximum yield and soluble fraction (AcSM) with 1% yield. The SEM micrographs of AcIM fractions were similar to AIM fractions. These showed a compact structure different from commercial Chitin. The presence of Chitin in P. Camembertii cultured in YPGA medium was also confirmed by ATR spectroscopy.
... spermicide (112) Agriculture plant elicitor (116) stimulation of chitinase and glucanase production (increased response to pathogen attack) (116) stimulation of chitinase activity in compost (change of bacterial and fungal genetic diversity) (117) antimicrobial (antifungal) agent and biopesticide (118,119) enhancing plant vitality and ability to degrade walls of fungi upon entry (120,121) fertilizer and biocontrol agent (118,122) enhancing biocontrol efficiency by addition to plant growth-promoting rhizobacteria (123)(124)(125) Textile and paper textile fibres (75) paper manufacture (additive) ...
... Biotechnology chitin affinity chromatography to selectively adsorb chitinase from a fermentation broth (112,126) affinity matrix (chitosan) for the separation of wheat germ agglutinin (112) enzyme and whole cell immobilizer (41, 90,127) N-acetyl chitobiose production from chitin using commercial hydrolytic enzymes (125) Chitinase and chitosanase production from L. paracasei, Pseudomonas and Streptomyces species (128)(129)(130)(131) microorganism immobilization for bioremediation of seawater polluted with crude oil (79) support for biosensors (41) bioseparation (90,91) Cosmetic ingredients for hair and skin care (moisturizer) (112) ...
Abstract Demineralization (DM) and deproteinization (DP) of shrimp shell Parapenaeus
longirostris using Lactobacillus helveticus, depends on the composition of culture medium,
and temperature of incubation. In a synthetic medium containing glucose, completely
different conditions are required for chitin recovery: 300 g/L of glucose and 35 C for maximal
DM (60%) and 80 g/L of glucose and 30 C for a maximum of DP (70%). The use of date's
juice shows that it is possible to extract chitin, in a single step, unlike the simple medium. ...
... Enhancing plant vitality and ability to degrade walls of fungi upon entry [74,75] Fertilizer and biocontrol agent [72,76] Enhancing biocontrol efficiency by addition to plant growth-promoting rhizobacteria [77,78,79] 5. ...
... Biotechnology Chitin affinity chromatography to selectively adsorb chitinase from a fermentation broth [65,81] Affinity matrix (chitosan) for the separation of wheat germ agglutinin [65] Enzyme and whole cell immobilizer [82,35,83] N-acetyl chitobiose production from chitin using commercial hydrolytic enzymes [79] Chitinase and chitosanase production from L. paracasei, Pseudomonas and Streptomyces species [84,85,86,87] Microorganism immobilization for bioremediation of seawater polluted with crude oil [88] Support for biosensors [82] Bioseparation [35,36] ...
Chitin is an abundant natural biopolymer having important properties such as biocompatibility and biodegradability combined with healing capability. Chitin is considerably versatile and promising biomaterial. It is widely accepted that chitin biopolymer is an important biomaterial in many aspects. Many studies on chitin have focused on its biomedical applications. In this paper, various aspects of chitin research including wide range of applications in bio and nanotechnology will be dealt with. This study looks at the contemporary research in chitin and its derivatives towards applications in various industrial and biomedical fields. In the present paper, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability. Biomaterials are materials and devices that are used to repair, replace or augment the living tissues and organs of the human body. The purpose of this study is to provide an understanding of the needs and uses of materials used in the human body and to explain the biomechanical principles and biological factors involved in achieving the long-term stability of replacement parts in the body. Blends of chitin with the polycaprolactone-based polyurethane can be effectively used to produce tough materials, useful in bio engineering applications. The mechanical strength of the blends demonstrated that they are able to support tensions and other loads above those required for bone replacement, making them good candidates for that purpose. Government concern over the environment, the depletion of fossil fuels, and climate change has promoted the development of bio nanocomposites. Compared to polymeric resources from petroleum, natural polymers from renewable resources have the advantages of biodegradability, biocompatibility, non-toxicity, high reactivity, low cost and ease of availability. Various applications of chitin are of great industrial importance. The proper utilization of crab shell waste not only solves the problem of their disposal but also forms the basis for many potential products used in the fields such as textiles, photography, medicine, agriculture, food processing etc. Therefore, the Investigation On Uses of Crab Based Chitin and Its Derivatives http://www.iaeme.com/IJMET/index.asp 457 editor@iaeme.com aim of this investigation is to enhance the utilization of crab waste and help to minimize the environmental pollution.
... Recently, an increase in the biocontrol efficacy of antagonistic yeasts in controlling postharvest diseases of fruits with the addition of chitin has been demonstrated [17]. Yu, Wang, Yin, Wang and Zheng [18] found that the disease incidence and lesion diameter of blue mold rot caused by P. expansum in pear fruits was significantly inhibited by Cryptococcus laurentii that had been cultivated in the nutrient yeast dextrose broth (NYDB) with chitin added, especially at the optimal concentration (1.0%) Ge, Zhang, Chen, Ma and Xu [19] reported that the antagonistic activity of Rhodotorula glutinis harvested either from NYDB with 0.5% chitin http added or from nutrient yeast chitin broth (NYCB: nutrient yeast chitin broth, in which chitin was the sole carbon source) was improved greatly relative to the activity of R. glutinis in NYDB without chitin [19]. Considering the potency of chitin in enhancing the efficacy of yeast and other antagonists in controlling postharvest diseases, little research has been conducted to determine the possible mechanisms involved. ...
... Yu et al. [18] reported that chitin can increase the population of many bacteria and yeasts thereby boosting their biocontrol efficacy. The biocontrol yeast R. mucilaginosa was selected mainly for its ability to rapidly colonize and multiply in the surfaces and wounds of fruits [30]. ...
... According to last year, diverse studies have been accomplished that is concerned with the production of yeast and bacteria from hydrolytic enzymes (Bahadou et al., 2018). The majority of Bacillus, as well as Pseudomonas genera, contain effective antagonists concerned with controlling pathogenic organisms because uninterruptedly affect the chitinase (Yu et al., 2008). (Shivakumar et al., 2014)concluded his work that kinetic studies, purification, and characterization were performed on chitinase enzyme of concerned B. subtilis, here the moderately purified enzyme revealed antifungal activity not only for R.solani, but also against Colletotrichum gloeosporioides. ...
The application of synthetic pesticides viz fungicide, bactericide, and nematicide to control the harmful phytopathogens that have a terrible impact on all living environments. Therefore, the developing countries have banned the further application of pesticides and usage of an alternate approach than synthetic pesticides, which have no side effect on plant health, human health, and on the living environment that are more cost-effective and eco-friendly behavior. The term biological control through beneficial microorganisms is an alternative approach to control the phytopathogens, which causes severe loss to important crops worldwide. This review article has focused on the antagonistic behavior of bacteria against fungal plant pathogens, bacteria, and nematodes. The bacterial species, especially Bacillus, Pseudomonas, and Streptomyces applied as antagonists against bundles of phytopathogens by a different mode of action. The antagonistic bacteria produce different antimicrobial compounds to suppress the growth of targeted pathogens. To suppress the growth of pre and post harvested fungal and bacterial pathogens, the biocontrol (BC) bacteria produce siderophore, antibiosis, parasitism, competition for space and nutrients, and biofilm formation. Induction of resistance in host plants also generated by biocontrol bacteria through the production of Indole acetic acid (IAA) and activities of the effector genes in host. The commercial products prepared by using the antagonistic bacteria such as Cryptococcus albidus, Pseudomonas syringae, Bacillus subtilis, Candida oleophila’ and Aureobasidium pullulans used to control the different phyto-fungal pathogens. This review article covers the three parts, in the first part, we discussed the antagonistic potential of bacteria against fungal pathogens, in the second part, we discuss the antagonistic potential of bacteria against bacterial pathogens and third part contain the antagonistic potential of bacteria against plant-parasitic nematodes.
... The disintegration of fungal pathogens hyphae by the enzymatic activity of antagonists causes cellular deformities, thereby resulting in cytological damage, mycelial lysis, deformation, increased cell membrane permeability, and cytoplasmic content leakage [86]. The extracellular enzymatic activity of numerous microbes was implicated in their antifungal action [117]. According to Urbina et al. [118], biocontrol of P. expansum in apples is facilitated by extracellular exo-b-1, 3-glucanase from yeast C. oleophila. ...
Postharvest disease management is vital to increase the quality and productivity of crops. As part of crop disease protection, people used different agrochemicals and agricultural practices to manage postharvest diseases. However, the widespread use of agrochemicals in pest and disease control has detrimental effects on consumer health, the environment, and fruit quality. To date, different approaches are being used to manage postharvest diseases. The use of microorganisms to control postharvest disease is becoming an eco-friendly and environmentally sounds approach. There are many known and reported biocontrol agents, including bacteria, fungi, and actinomycetes. Nevertheless, despite the abundance of publications on biocontrol agents, the use of biocontrol in sustainable agriculture requires substantial research, effective adoption, and comprehension of the interactions between plants, pathogens, and the environment. To accomplish this, this review made an effort to locate and summarize earlier publications on the function of microbial biocontrol agents against postharvest crop diseases. Additionally, this review aims to investigate biocontrol mechanisms, their modes of operation, potential future applications for bioagents, as well as difficulties encountered during the commercialization process.
... Studies have shown that antagonistic yeasts in combination with ammonium molybdate can improve their biocontrol effect on pear fruit (Wan and Tian, 2005). Yu et al. (2008) found that 1 % chitin can induce C. laurentii to produce chitinase, thereby enhancing its control efficacy against Penicillium expansum in pear fruit. The biocontrol activity of Rhodotorula glutinis was enhanced in combination with SA against P. expansum and Alternaria alternata in sweet cherry fruit (Guo et al., 2003). ...
Our previous study showed that γ-aminobutyric acid (GABA) can significantly enhance the biological control efficacy of Sporidiobolus pararoseus Y16 on postharvest diseases of grapes. The possible physiological biocontrol mechanisms of the yeast have been reported previously, however, the associated molecular mechanisms were unclear. This study aimed to investigate the possible molecular mechanisms behind the enhanced biological control efficacy of S. pararoseus Y16 cultured with GABA based on transcriptome analysis. In addition, the activities of catalase (CAT) and chitinase (CHI) and the content of malondialdehyde (MDA) in S. pararoseus Y16 were investigated. The results showed that after the addition of 4 mg/mL GABA, the activities of CAT and CHI in S. pararoseus Y16 were significantly increased, and the content of MDA accumulation was decreased. Transcriptome analysis found that GABA-treated S. pararoseus Y16 can improve the ability of yeast ion transport, cell wall remodeling, antioxidants, growth and reproduction, resistance to stress, amino acid synthesis, etc., resulting in increased antagonistic efficacy of S. pararoseus Y16. These results provide a reference for future research on the use of antagonistic yeasts to prevent and control postharvest diseases of fruits and vegetables, and provide a theoretical basis for the practical application of antagonistic yeasts.
... Besides, a vast number of reports evidenced that antagonistic yeasts have significant control effects on postharvest diseases of fruits, mainly blue mold decay of pears caused by P. expansum. The antagonistic yeasts are R. glutinis (Zhang et al., 2008), Cryptococcus laurentii (Yu et al., 2008), Rhodosporidium paludigenum (Zhu et al., 2015), Wickerhamomyces anomalus , C. podzolicus (Zhao et al., 2020) and so on. However, the knowledge on the PAT reduction efficiency of antagonistic yeasts in stored pears at different conditions is limited. ...
Meyerozyma guilliermondii is an antagonistic yeast that efficiently controls the blue mold decay of pears and potentially degrades patulin in vitro conditions. However, the possible patulin controlling efficacy of M. guilliermondii in pears remains unclear. In this study, the patulin controlling effect of M. guilliermondii in pears was investigated. The results showed that M. guilliermondii could effectively control patulin content production by Penicillium expansum in shuijing pear wounds from 3 d to 11 d. However, M. guilliermondii has a poor patulin control effect on fragrant pear and dangshan pear wounds. The patulin degradation ability of M. guilliermondii in shuijing pear wounds increased with the higher concentration of the yeast cells, and 1 × 10⁸ cells/mL showed the best patulin control effect. In shuijing pears, M. guilliermondii could effectively control patulin at 20°C and 4°C in wounds as well as the whole fruits. Our results provide a safe and efficient strategy to detoxify patulin using M. guilliermondii, thereby limitting the risks of patulin in shuijing pears.
... Bacillus and Pseudomonas genera are effective antagonists in controlling pathogens because they contain the chitinase enzyme that can hydrolyze the ß-1,4 bonds among N-acetylglucosamine (NacGlc) in chitin; this polysaccharide polymer makes up the cell walls of several pathogenic fungi and the exoskeleton of invertebrates. Therefore, chitinase is well known for its antifungal or microbial properties (Yu et al. 2008). Mohammadi et al. (2017) reported the isolation of extracellular enzymatic activity of potential bacteria (B. ...
Background
In Indonesia, the postharvest fruit loss is 25%, so the economic loss from the export of various fruits is estimated at US$ 58,966,861. One of the causes for the loss is postharvest pathogens. Postharvest fruit rot is caused mainly by fungi, some of which produce mycotoxins harmful to human health. Therefore, in meeting the global food safety requirements, Indonesia should develop a biological control strategy for postharvest fruit diseases. This paper is a review based on observations, a literature review of postharvest biological control of citrus and other subtropical fruits, and an overview of strategies and prospects for their application in Indonesia.
Main body
The pathogens that cause diseases on citrus fruits, apples, grapes, and strawberries in Indonesia produce mycotoxins, namely Fusarium sp., Aspergillus terreus , Aspergillus sp., Penicillium sp., and Alternaria sp. The potential biological agents are from the yeast group, such as the Candida genera, the bacterial group, such as the Bacillus and Pseudomonas genera, and the fungal group, such as the Muscodor and Trichoderma genera.
Conclusion
Through mutually additive and synergistic multiple reduction methods in cooperation with the vanguards, postharvest disease control emphasizes disease prevention using several methods. Each method reduces the percentage of damage by a certain amount to produce highly effective controls.
... The antimicrobial actions of many species of Bacillus and Pseudomonas are credited to extracellular chitinase released by them. [112] Detrimental effects of enzymatic actions on pathogen hyphae include cellular deformities, protoplasmic damage, mycelial distortion and lyses, leakage of cellular contents, and changes in membrane permeability. [104] Therefore, the loss of fungal cytoplasm resulting from cell wall disintegration is one of the key modes accountable for biocontrol actions of antagonists. ...
The multitasked Nitric oxide (NO) is a highly reactive, gaseous molecule that is endogenously produced in the plant cells through various routes. In the plant, NO participates in numerous physiological processes including growth and development as well as adaptation against (a)biotic stresses. At the molecular level, NO acts as a redox-related signaling molecule whose function entirely depends on two factors (concentration and spatial generation pattern). Once generated, it directly or indirectly interacts with other redox-related molecules (O2−, H2O2, H2S, NO2−) and potentially interacts with various biomolecules including proteins, lipids, hormones, and nucleic acid at the downstream level. The variety of NO acting mechanisms include direct reaction with redox molecule, metal-nitrosation of transient metals, protein tyrosine nitration, and S-nitrosation. Since the discovery of the physiological role of NO in plants, numerous studies have been conducted to elucidate the production pathways, mechanism of action, and its ultimate effect in distinct physiological processes. However, over time, some questions still remain unanswered, and with new knowledge on interactions of NO with fatty acids and nucleic acids, more possible regulatory roles of NO in mitigation of stresses is still under investigation. Therefore, this chapter discusses the NO production, mechanism of action, and role in the regulation of plant’s (a)biotic stress response.
... An overexpressed MfChi chitinase in Pichia pastoris controlled the growth of M. fructicola and M. laxa in vitro, and in vivo on peach fruits. The antimicrobial actions of many species of Bacillus and Pseudomonas are credited to the extracellular chitinolytic enzymes they release (Yu et al. 2008). Some other detrimental effects of enzymatic actions on pathogens are cellular deformities, protoplasmic damages, mycelial distortion and lyses, leakage of cellular contents, and changes in membrane permeability (Di Francesco et al. 2016). ...
Chitin is an important structural component of many plant pathogenic fungi. Similarly, it is also an important part of the insect cuticle and peritrophic matrices, which function as a permeability barrier, enhance digestive processes and protecting the brush border from mechanical disruption as well as from attacks by toxins and pathogens. Chitin degrading lytic enzymes (such as chitinases, and glucanase) produced by bacteria and other microorganisms can impede the growth of many insect pests and fungal phytopathogens that pose a severe risk to global crop production. Pathogenic microorganisms produce a variety of lytic enzymes such as proteases, chitinases, lipases etc. which play an important role in the virulence of entomopathogens. Many chitinolytic bacteria have the potential to control pests and fungal pathogens of crops owing to their ability to disintegrate chitin containing cellular structures. Currently, efforts are being made to discover producers of chitinolytic enzymes in nature. Production of lytic enzymes has been reported in a number of virulent pathogens such as Serratia, Pseudomonas or Bacillus spp. Bioprospecting and exploitation of chitinolytic bacteria will help in developing biocontrol agents, which have the potential to control fungal plant pathogens and insect pests. Thus, these bacteria-based biofungicides and biopesticides may replace or supplement the chemical fungicides and insecticides, reducing the negative impact of chemicals on the environment and supporting the sustainable development of agriculture-based ecosystem. This chapter focuses on the scope and potential of chitinolytic bacterial and fungal organisms in the management of insect pests and fungal pathogens of agricultural crops.
... against B. cinera grey mold pathogen of strawberry with the ability to produce extracellular antifungal hydrolytic enzymes such as chitinase, b-1, 3-glucanase, cellulase and protease. Antifungal activity of Bacillus and Pseudomonas spp. was attributed to the extracellular chitinolytic activity (Yu et al., 2008). Banani et al. (2015) reported chitinase activity of antagonistic yeast Metschnikowia fructicola and demonstrated that chitinase gene MfChi was over induced in the presence of yeast Monilinia fructicola cell wall. ...
Fungal diseases result in significant losses of fruits and vegetables during handling, transportation and
storage. At present, post-production fungal spoilage is predominantly controlled by using synthetic
fungicides. Under the global climate change scenario and with the need for sustainable agriculture,
biological control methods of fungal diseases, using antagonistic microorganisms, are emerging as
ecofriendly alternatives to the use of fungicides. The potential of microbial antagonists, isolated from a
diversity of natural habitats, for postharvest disease suppression has been investigated. Postharvest
biocontrol systems involve tripartite interaction between microbial antagonists, the pathogen and the
host, affected by environmental conditions. Several modes for fungistatic activities of microbial
antagonists have been suggested, including competition for nutrients and space, mycoparasitism,
secretion of antifungal antibiotics and volatile metabolites and induction of host resistance. Postharvest
application of microbial antagonists is more successful for efficient disease control in comparison to preharvest
application. Attempts have also been made to improve the overall efficacy of antagonists by
combining them with different physical and chemical substances and methods. Globally, many microbebased
biocontrol products have been developed and registered for commercial use. The present review
provides a brief overview on the use of microbial antagonists as postharvest biocontrol agents and
summarises information on their isolation, mechanisms of action, application methods, efficacy
enhancement, product formulation and commercialisation.
... According to last year, diverse studies have been accomplished that is concerned with the production of yeast and bacteria from hydrolytic enzymes (Bahadou et al., 2018). The majority of Bacillus, as well as Pseudomonas genera, contain effective antagonists concerned with controlling pathogenic organisms because uninterruptedly affect the chitinase (Yu et al., 2008). (Shivakumar et al., 2014)concluded his work that kinetic studies, purification, and characterization were performed on chitinase enzyme of concerned B. subtilis, here the moderately purified enzyme revealed antifungal activity not only for R.solani, but also against Colletotrichum gloeosporioides. ...
The application of synthetic pesticides viz fungicide, bactericide, and nematicide to control the harmful phytopathogens that have a terrible impact on all living environments. Therefore, the developing countries have banned the further application of pesticides and usage of an alternate approach than synthetic pesticides, which have no side effect on plant health, human health, and on the living environment that are more cost-effective and ecofriendly behavior. The term biological control through beneficial microorganisms is an alternative approach to control the phytopathogens, which causes severe loss to important crops worldwide. This review article has focused on the antagonistic behavior of bacteria against fungal plant pathogens, bacteria, and nematodes. The bacterial species, especially Bacillus, Pseudomonas, and Streptomyces applied as antagonists against bundles of phytopathogens by a different mode of action. The antagonistic bacteria produce different antimicrobial compounds to suppress the growth of targeted pathogens. To suppress the growth of pre and post harvested fungal and bacterial pathogens, the biocontrol (BC) bacteria produce siderophore, antibiosis, parasitism, competition for space and nutrients, and biofilm formation. Induction of resistance in host plants also generated by biocontrol bacteria through the production of Indole acetic acid (IAA) and activities of the effector genes in host. The commercial products prepared by using the antagonistic bacteria such as Cryptococcus albidus, Pseudomonas syringae, Bacillus subtilis, Candida oleophila' and Aureobasidium pullulans used to control the different phyto-fungal pathogens. This review article covers the three-parts, in the first part, we discussed the antagonistic potential of bacteria against fungal pathogens, in the second part, we discuss the antagonistic potential of bacteria against bacterial pathogens and third part contain the antagonistic potential of bacteria against plant-parasitic nematodes.
... Bacillus sp. I 8 at 10 7 cfu/ml was most effective antagonist against Diplodia sp [38][39][40][41]. ...
Apple (Malus domestica Borkh) is an important horticultural crop that is affected by the number of diseases round the year. The fruit is particularly susceptible to a number of pathogens both pre-and post-harvest. Management of these diseases is based mostly on the application of synthetic fungicides with obvious disadvantages of environmental pollution, health hazards, pathogen resistance, etc. In the present study, eleven epiphytes were isolated using potato dextrose agar, nutrient agar and yeast maltose agar media. Amongst them, five fungal isolates viz., Aspergillus sp. (I 1), Penicillium sp. (I 2), Fusarium sp. (I 3), Rhizopus sp. (I 4) and Alternaria sp. (I 5) and six bacterial isolates viz., Pseudomonas sp. (I 6), Pseudomonas sp. (I 7), Bacillus sp. (I 8), Bacillus sp. (I 9), Staphylococcus sp. (I 10) and Micrococcus sp. (I 11) were predominantly noticed under all the three methods (leaf impression, serial dilution and fruit washing) and were hence, used for further studies. The highest average colony count of 3.62 colonies/cm 2 was recorded in fruit washing method followed by leaf impression (3.17) and lowest in serial dilution method (2.12). The in vitro screening of various bacterial and fungal epiphytes revealed that isolates of Pseudomonas sp. (I 6) and Bacillus (I 8 and I 9) were the only bacterial strains capable of inhibiting the growth of all the test pathogens using dual culture method. Assays on wounded apples revealed that Pseudomonas sp. I 6 at 10 7 cfu/ml was effective antagonist against Penicillium sp. and Fusarium sp., Bacillus sp. I 9 at 10 7 cfu/ml was effective antagonist against Alternaria sp., whereas, Bacillus sp. I 8 at 10 7 cfu/ml was most effective antagonist against Diplodia sp. The present study revealed that the antagonists were more or less efficient towards each pathogen and can be utilized for the management of post-harvest diseases of apple.
... against B. cinera grey mold pathogen of strawberry with the ability to produce extracellular antifungal hydrolytic enzymes such as chitinase, b-1, 3-glucanase, cellulase and protease. Antifungal activity of Bacillus and Pseudomonas spp. was attributed to the extracellular chitinolytic activity (Yu et al., 2008). Banani et al. (2015) reported chitinase activity of antagonistic yeast Metschnikowia fructicola and demonstrated that chitinase gene MfChi was over induced in the presence of yeast Monilinia fructicola cell wall. ...
... Several parameters control the size of the nanoparticles and consequently affects the plant responses towards the nano-chitosan, among these parameters are the degree of deacetylation (DD), molecular weight and concentration of chitosan, chitosan: TPP mass ratio, pH, temperature and rate of mixing of TPP and chitosan [77,78] in addition to size distribution/polydispersity index (PDI), surface charge (zeta-potential) and functional/encapsulated component [77]. Spiders Ascomydes Chionoecetes opilio [35] Geolycosa vultuosa [40] Mycelium [44] Podophthalmus vigil [36] Hogna radiate [40] Penicillium [45] Paralithodes amtschaticus [37] Nephila edulis [41] Carcinus mediterraneus [38] Water lobster Scorpions Yeast (b type) [46] Crayfish [39] Mesobuthus gibbosus [42] Blastomycota Blastocladiaceae [47] Prawn ...
Chitosan has been termed as the most well-known among biopolymers, receiving widespread attention from researchers in various fields mainly, agriculture, food, and health. Chitosan is a deacetylated derivative of chitin, mainly isolated from waste shells of the phylum Arthropoda after their consumption as food. Chitosan molecules can be easily modified for adsorption and slow release of plant growth regulators, herbicides, pesticides, and fertilizers, etc. Chitosan as a carrier and control release matrix that offers many benefits including; protection of biomolecules from harsh environmental conditions such as pH, light, temperatures and prolonged release of active ingredients from its matrix consequently protecting the plant's cells from the hazardous effects of burst release. In the current review, tends to discuss the recent advances in the area of chitosan application as a control release system. Also, future recommendations will be made in light of current advancements and major gaps.
Free download link: https://authors.elsevier.com/c/1anEK_3ENNTl47
... The antagonist hydrolytic enzymes, especially chitinases, glucanases, cellulases and proteases, may disintegrate the structure of the pathogen cell wall (Spadaro and Droby 2016). The antagonistic efficiency of Bacillus and Pseudomonas spp. is greatly attributed to such a biological activity, originating from the direct action of chitinase (Yu et al. 2008). ...
Postharvest losses mostly occur due to senescence, microbial decay and pathogen attack, which greatly affect the quantity and quality of food. Number of techniques are used to minimize the postharvest lossesand diseases, by treating products with several physical, biochemical and biological means, directly controlling pathogen infestation and extends products shelf life. Numerous physical techniques (refrigeration, cold atmosphere storage, low pressure storage and modified atmosphere storage) used to control postharvest diseases are either curative or preventive, aiming at halting disease spreading. Among physical techniques, heat treatment is considered the most effective technique especially to manage fungal diseases, which are the most common in postharvest (chilling injury). Moreover, UV treatments (UV-C, UV-B and UV-A) are used to sterilize commodities, reducing the decay due to microorganisms, helping in extending shelf life and to maintain fruits and vegetables quality. Recently, exogenous application of calcium based chemicals helped in stabilizing plant cell wall, maintaining quality of fruits and vegetables. Postharvest biological control agents have been extensively studied. By introducing natural enemies of the pathogen to be targeted its population may be reduced by restricting normal growth or activity. Additionally, volatile compounds are usually applied on a commercial scale for flavoring and seasoning agents in foods, that strongly reduce the incidence of microbial pathogens. These volatile compounds have various properties such as antiprotectants, antimicrobial, are less harmful to mammalians, are environment friendly, and could be used as alternatives for chemical fungicides. Plants represent a huge reservoir of natural compounds harboring fungicidal activities with potential to replace synthetic fungicides. Many species produce volatile substances and essential oils that could serve as antifungal or antimicrobial preservatives for fruits and other harvested commodities. Thus, combining various treatment options may offer a more consistent, durable, practical, and sustainable solution to stakeholders and producers for postharvest control of infections.This chapter will highlight the importance of conventional and modern technologies used to control pathogens infestation, postharvest disorders to maintain quality of fruit and vegetables.
... The antimicrobial actions of many species of Bacillus and Pseudomonas are credited to extracellular chitinase released by them. [112] Detrimental effects of enzymatic actions on pathogen hyphae include cellular deformities, protoplasmic damage, mycelial distortion and lyses, leakage of cellular contents, and changes in membrane permeability. [104] Therefore, the loss of fungal cytoplasm resulting from cell wall disintegration is one of the key modes accountable for biocontrol actions of antagonists. ...
Post-harvest commodities wastage due to decay caused by the pathogenic fungi generates a huge amount of economic losses worldwide. Different species of Penicillium spoil various foodstuffs and produce mycotoxins, alkaloids and other harmful cellular metabolites in the food. Presently, synthetic fungicides, mainly used for fungal diseases control, are associated with harmful impacts on the environment and consumer health. Hence, non-fungicide based eco-friendly and commercially viable alternative is proposed for ensuring food safety. In recent years, the safer options that have been explored include microbe mediated biological control, botanical pesticides, use of generally regarded as safe (GRAS) compounds, and innovative physical approaches including cold plasma, and pulsed light techniques. These emerging technologies could be utilized in the multiple hurdle concept of disease management for suppressing pathogens growth at different stages of spoilage development. This review, first of its kind, summarizes the exclusive information on Penicillium spp. induced spoilage, associated toxicological concerns and the potential of non-fungicide-based promising approaches for managing fungal wastage in the harvested horticultural commodities.
... The inhibitory effect of chitosan was also demonstrated against many of soil born fungi (Stossel and Leuba;El Ghouth et al, 1990) and Rhizopus stolonifer (Yarahamdi et al, 2014). Also, chitosan was used to control post-harvest diseases of many fruits such as Pear (Yu et al, 2008) and Strawberry (Ge et al, 2010;Bhaskara et al, 2000). Chitosan is known to be a potential elicitor of many plant defense responses, including the accumulation of chitinases (Mauch et al, 1984) and synthesis of proteinase inhibitors in tomato leaves (Pearce and Ride, 1982). ...
... During the last decade, different research studies have been performed on hydrolytic enzymes that produce bacteria and yeasts [29]. The genera Bacillus and Pseudomonas are considered as some of the most efficient antagonists in phytopathogen control due to the direct action of chitinase [55]. Shivakumar et al. [56] performed partial purification, characterization, and kinetic studies of the chitinase enzyme of the bacteria Bacillus subtilis JN032305, in which the partially purified enzyme not only showed antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides but also increased pepper seed germination when infected by the mentioned fungi. ...
This review deals with the main mechanisms of action exerted by antagonistic bacteria, such as competition for space and nutrients, suppression via siderophores, hydrolytic enzymes, antibiosis, biofilm formation, and induction of plant resistance. These mechanisms inhibit phytopathogen growth that affects postharvest fruit since quality and safety parameters are influenced by the action of these microorganisms, which cause production losses in more than 50% of fruit tree species. The use of synthetic fungicide products has been the dominant control strategy for diseases caused by fungi. However, their excessive and inappropriate use in intensive agriculture has brought about problems that have led to environmental contamination, considerable residues in agricultural products, and phytopathogen resistance. Thus, there is a need to generate alternatives that are safe, ecological, and economically viable to face this problem. Phytopathogen inhibition in fruit utilizing antagonist microorganisms has been recognized as a type of biological control (BC), which could represent a viable and environmentally safe alternative to synthetic fungicides. Despite the ecological benefit that derives from the use of controllers and biological control agents (BCA) at a commercial level, their application and efficient use has been minimal at a global level.
... Low-toxicity chemicals such as generally regarded as safe (GRAS) salts (Palou et al., 2002;Qin et al., 2010;Ciccarese et al., 2013;Cai et al., 2015), plant extracts and essential oils (Chen et al., 2014;Mari et al., 2016), and antifungal peptides and small proteins (López-García et al., 2000;Badosa et al., 2009;Alem et al., 2014;Harries et al., 2015), have been shown to display antifungal activity against postharvest diseases. Synergistic effects for control of fruit decay were observed when biological control agents were used in combination with lowtoxicity chemicals including calcium chloride (Gholamnejad and Etebarian, 2009), sodium bicarbonate (Janisiewicz et al., 2008), chitin (Yu et al., 2008), salicylic acid (Qin et al., 2003), boron (Cao et al., 2012), and glycine betaine (Liu et al., 2011). Cinnamic acid is an organic acid of natural origin from cinnamon bark or benzoin and is widely applied in the food industry as a common food additive (Zhang et al., 2015b). ...
Cinnamic acid was effective to control blue mold caused by Penicillium italicum in ‘Orah’ mandarins. The inhibition of fruit decay was positively correlated with cinnamic acid concentration. Cinnamic acid at 1.5 mM, in combination with the biocontrol yeast Cryptococcus laurentii at 1 × 10⁷ cells/mL, provided synergistic effects against P. italicum. Population dynamic analysis demonstrated that the growth of C. laurentii in fruit rind wounds was not significantly influenced by cinnamic acid. C. laurentii multiplied rapidly, regardless of whether the yeast was used alone or combined with cinnamic acid. By contrast, spore germination and mycelial growth of P. italicum in the culture medium were markedly inhibited by cinnamic acid. By using propidium iodide fluorescent staining, loss of membrane integrity in P. italicum was observed after cinnamic acid treatment. Furthermore, cinnamic acid led to the leakage of cellular constituents including soluble proteins and carbohydrates from hyphae of P. italicum. These results indicated that the fungal pathogen P. italicum is more sensitive to cinnamic acid than the biocontrol yeast C. laurentii. Taken together, our data suggest that the enhancement in biocontrol efficacy of C. laurentii might be associated with the differential influence of cinnamic acid on the antagonistic yeast and the fungal pathogen.
... https://doi.org/10.17221/103/2017-PPS Moreover, a large number of yeasts and bacteria colonising the surface of fruits and vegetables have been reported as effective agents of biological control against postharvest diseases (Mikani et al. 2008;Yu et al. 2008). These various biological agents showed a high ability to control several postharvest pathogens in different crops such as apples (Janisiewicz 1987), grapes (Senthil et al. 2011), peaches (Di Francesco et al. 2017, strawberries (Lima et al. 1997), citruses (Nunes et al. 2009), and tomatoes (Sadfi-Zouaoui et al. 2008a). ...
Botrytis cinerea, the causal agent of grey mould, is a predominant agent causing extensive postharvest and quality losses of apples in Tunisia and worldwide. Efforts to manage this disease have met with limited success. For this reason, the use of microorganism preparations to control fungal diseases as an alternative to fungicides became an urgent need. From a total of 60 epiphytic yeasts, 10 were assessed in vitro against B. cinerea and selected isolates showing antagonism were evaluated for their ability to suppress the grey mould in vivo. On Petri plates, the most promising strains (three strains of Aureobasidium pullulans, one Cryptococcus flavescens, and one Citeromyces matritensis) showed a zone of inhibition against the pathogen fungus not exceeding 10 mm. In vivo, these isolates showed a remarkable antifungal activity since they significantly reduced disease severity on apples from 63% to 95% compared to the control. In conclusion, the work has demonstrated that the three strains, L7 of Aureobasidium pullulans, L2 of Citeromyces matritensis, and L10 of Cryptococcus flavescens, were highly effective and can be used as potential biocontrol agents in controlling the post-harvest decay of apples caused by B. cinerea.
... A possible role of chitinases in defence against other fungi had been demonstrated with the yeasts Pa. laurentii and Candida oleophila (Bar-Shimon et al., 2004;Yu et al., 2008). Several soilrelated yeasts, including N. albida (cited as Cr. ...
Fungi that inhabit forest topsoil can be distinguished into two morphological guilds: filamentous, multicellular fungi and predominantly unicellular yeasts. The nutritional mode of these two groups is expected to differ due to the dependence of yeasts on locally present nutrients. Here we explored the decomposition potential and carbon utilization profiles of dominant yeasts from the temperate forest topsoil. The results indicated that despite taxonomic heterogeneity, yeasts represent a fungal group with a specific nutritional strategy that is dissimilar from other tested fungi. While the efficient decomposition of hemicellulose, cellulose or chitin appeared to be restricted to only a few yeast taxa, carbon source utilization assays indicated that most yeasts could efficiently act as opportunists, utilizing the decomposition products generated by other microbes. Importantly, a large fraction of enzyme activity was associated with yeast cell surfaces indicating their adaptation to generate decomposition products so that they are readily available for intake.
... against B. cinera grey mold pathogen of strawberry with the ability to produce extracellular antifungal hydrolytic enzymes such as chitinase, b-1, 3-glucanase, cellulase and protease. Antifungal activity of Bacillus and Pseudomonas spp. was attributed to the extracellular chitinolytic activity (Yu et al., 2008). Banani et al. (2015) reported chitinase activity of antagonistic yeast Metschnikowia fructicola and demonstrated that chitinase gene MfChi was over induced in the presence of yeast Monilinia fructicola cell wall. ...
Fungal diseases result in significant losses of fruits and vegetables during handling, transportation and storage. At present, post-production fungal spoilage is predominantly controlled by using synthetic fungicides. Under the global climate change scenario and with the need for sustainable agriculture, biological control methods of fungal diseases, using antagonistic microorganisms, are emerging as ecofriendly alternatives to the use of fungicides. The potential of microbial antagonists, isolated from a diversity of natural habitats, for postharvest disease suppression has been investigated. Postharvest biocontrol systems involve tripartite interaction between microbial antagonists, the pathogen and the host, affected by environmental conditions. Several modes for fungistatic activities of microbial antagonists have been suggested, including competition for nutrients and space, mycoparasitism, secretion of antifungal antibiotics and volatile metabolites and induction of host resistance. Postharvest application of microbial antagonists is more successful for efficient disease control in comparison to pre-harvest application. Attempts have also been made to improve the overall efficacy of antagonists by combining them with different physical and chemical substances and methods. Globally, many microbe-based biocontrol products have been developed and registered for commercial use. The present review provides a brief overview on the use of microbial antagonists as postharvest biocontrol agents and summarises information on their isolation, mechanisms of action, application methods, efficacy enhancement, product formulation and commercialisation.
... Their competition for nutrients such as amino acids, sugars and Fe 3þ, as an important mechanism enable yeasts to compete for nutrients against other antagonists ( Bencheqroun et al., 2007;Saravanakumar, Ciavorella, Spadaro, Garibaldi, & Gullino, 2008;Sipiczki, 2006). Additionally, modes of action such as mycoparasitism, induced resistance and the production of lytic enzymes viz., b-1, 3-glucanase and chitinase exhibited by yeasts have been reported (Ippolito & Nigro, 2000;Saligkarias, Gravanis, & Epton, 2002;Yu, Wang, Yin, Wang, & Zheng, 2008). ...
Background The application of physical (thermal and non-thermal) treatments in combination with biocontrol agents for the control of postharvest fungi has achieved significant research attention. In order to make combined nonchemical agents commercially suitable for postharvest treatment of other commodities, there is the need to study their individual effects and then integrated effects to present them as economically viable, resilient and persistent. Scope and approach In this article, various physical treatment methods (thermal and non-thermal) have been used to enhance the bioefficacy of microbial agents against postharvest diseases of fruits and the possible mode of action were reviewed. Additionally, the interrelationship between fungal virulence, host response and environmental factors that influence infection rate and production of mycotoxin has also been highlighted. Key findings and conclusions Physical treatments act as disinfectants of surfaces of produce prior to application of antagonistic yeasts that provide persistent protective action over an extensive period. Physical methods by heat treatment tends to seal or cure openings on the produce in order to limit the sites for pathogen penetration and restriction of secondary infections by biofilm formation after application of antagonistic yeasts or bioactive compounds. Thus, this phenomenon slow down changes in fruits respiration and metabolic activity. Heat has the potential to up-regulate proteins in fruits, which correlates with defense response and redox metabolism; consequently, demonstrates a physiological adaptation to environmental stress. From literature, there is limited information on the effect of ohmic heat method combined with antagonistic on decay causing pathogens and shelf life of fruits. Furthermore, the employment of novel tools available in molecular biology will enable in-depth explanation of other physiological and biochemical pathways on which the treatment effects are supported.
... Among these antagonists, yeasts that do not produce toxic secondary metabolites but have an inhibitory effect against pathogens are available and have been pursued actively (Zong et al., 2010). Many antagonistic yeasts including Candida oleophila, Cryptococcus laurentii, Metschnikowia fructicola, and Pichia guilliermondii were reported to greatly inhibit Botrytis, Penicillium, Mucor, Rhizopus, and Aspergillus in postharvest fruits (Banani et al., 2015;Bar-Shimon et al., 2004;Lahlali et al., 2011;Yu et al., 2008). ...
The use of antagonistic yeasts to control postharvest pathogens is a promising alternative to fungicides. The effect of the yeast antagonists Pichia membranaefaciens and Kloeckera apiculata for controlling brown rot of plums in postharvest and the antifungal activity of the two yeast strains in in vitro conditions against Monilinia fructicola were investigated. In in vivo trials, both P. membranaefaciens and K. apiculata showed a significant reduction of rot incidence produced by M. fructicola by 76.0% and 65.8%, respectively. In in vitro trials, spore germination and mycelial growth of M. fructicola were markedly inhibited by P. membranaefaciens and K. apiculata. In addition, the two antagonistic yeasts, especially K. apiculata, had attachment to the hyphae of M. fructicola. Moreover, P. membranaefaciens and K. apiculata secreted hydrolytic enzymes, such as chitinase (CHI) and β-1, 3-glucanase (GLU). According to these results, P. membranaefaciens and K. apiculata might have the ability to parasitize M. fructicola. The volatile organic compounds (VOCs) produced by P. membranaefaciens and K. apiculata had a significant inhibitory effect on M. fructicola in vitro and in vivo. VOCs in a simultaneous incubation (SI) trial showed the best inhibition.
The application of some natural compounds and cold storage can reduce postharvest loss and improve fruit quality and storability, which increase the fruit marketing period and exportation to distant markets. This study investigated the effectiveness of using coatings based on natural polymers to prolong the shelf life of fruits and protect their tissues from damage. Specifically, the researchers examined the impact of putrescine (PUT), chitosan (CTS) and chitosan–putrescine nano-composites (CTS-PUT NPs) on preserving the quality and reducing decay in strawberry. Strawberries were treated with either 1 mM or 2 mM of PUT, 0.1% CTS, 0.1% CTS-PUT NPs or distilled water at a temperature of 20°C for 5 min and then stored at 4°C for 12 days. At the end of the storage period, the lowest decay percentage was related to the treatments of CTS-PUT NPs and CTS, and the highest was observed in the control. The results showed that all coating treatments effectively prevented the excessive loss of ascorbic acid, fruit firmness, total soluble solids (TSS), and acidity (TA) compared to control at the end of the storage period. Additionally, strawberries treated with CTS-PUT NPs and CTS demonstrated the highest levels of total anthocyanin and total flavonoid. Antioxidant enzyme activities containing CAT and SOD were preserved at higher levels in treated strawberries than in the control during cold storage. These results confirm that the application of CTS and CTS-PUT NPs can effectively preserve fruit quality and prolong the longevity of strawberries during cold storage by enhancing their antioxidant capacity and scavenging free radicals.
Contaminations of pathogenic and spoilage microbes on foods are threatening food safety and quality, highlighting the importance of developing antimicrobial agents. According to different working mechanisms, the antimicrobial activities of yeast-based agents were summarized from two aspects: antagonism and encapsulation. Antagonistic yeasts are usually applied as biocontrol agents for the preservation of fruits and vegetables via inactivating spoilage microbes, usually phytopathogens. This review systematically summarized various species of antagonistic yeasts, potential combinations to improve the antimicrobial efficiency, and the antagonistic mechanisms. The wide applications of the antagonistic yeasts are significantly limited by undesirable antimicrobial efficiency, poor environmental resistance, and a narrow antimicrobial spectrum. Another strategy for achieving effective antimicrobial activity is to encapsulate various chemical antimicrobial agents into a yeast-based carrier that has been previously inactivated. This is accomplished by immersing the dead yeast cells with porous structure in an antimicrobial suspension and applying high vacuum pressure to allow the agents to diffuse inside the yeast cells. Typical antimicrobial agents encapsulated in the yeast carriers have been reviewed, including chlorine-based biocides, antimicrobial essential oils, and photosensitizers. Benefiting from the existence of the inactive yeast carrier, the antimicrobial efficiencies and functional durability of the encapsulated antimicrobial agents, such as chlorine-based agents, essential oils, and photosensitizers, are significantly improved compared with the unencapsulated ones.
Chitosan is a naturally occurring polysaccharide extracted from the shells of crustaceans, such as shrimp, crabs, and cell walls of fungi which were reported to be active against various biotic and abiotic stresses. It is a nontoxic, biodegradable, and biocompatible compound that favors potentially broad applications, due to its antifungal, antibacterial, and antiviral properties. It has been used successfully in plants as a plant growth promoter, in soil correction, improver of secondary metabolites production as well as an activator of plant defense mechanisms against plant pathogens. Based on these and other properties and in concern to reducing the usage of agrochemicals in the present agricultural systems these kinds of organic products should be developed and encouraged to reduce the negative impact of diseases on yield and quality of crops. In this context, the present review recapitulates the properties and uses of chitosan and will focus on their applications in plant disease management and mechanisms of action during plant-pathogen interactions.
Plant microbiome comprising distinct microbial community is meticulously associated with the general well-being of any plant that determines its growth, fitness, disease resistance, and productivity. Endophytes offer an added advantage over other microbial associates of plants in that they are always in contact with the host in varied environmental conditions. The many fold mechanisms deployed by these endophytes in protecting their host plants from diseases make them a promising candidate for the preparation of bioformulations for plant diseases and, thus, an effective substitute to chemicals. The current chapter explores the various mechanisms employed by the endophytes in offering disease resistance to their host plants. The latter part of the chapter discusses the various techniques that are currently employed for improving the design and performance of microbial biocontrol agents and also summarizes the novel technologies available in contriving these bioformulations, which have a crucial role in their application and commercialization.
Sustainable nanomaterials (SNMs) from wood, sugarcane and crab shell were prepared and used to coat selected fruits. The properties of SNMs and selected fruits were characterized and strawberry was used as an example to test antifungal activity and freshness preservation of the SNMs. The SNMs with their nano-structured morphology form strong shear-thinning dispersions for easy spraying on fruit surfaces. The fruit surface free energy was influenced by its surface morphology, predominant surface wax components, and cutin monomers. The antifungal activity of SNMs was influenced by their surface functional groups and particle size (crystals vs fibers). The coblend of wood nanocrystals (WCNCs) and chitosan nanofiber (CSNFs) exhibited the best antifungal property, which was comparable with the performance of the fungicide thiabendazole (80 mg L⁻¹). The weight loss and color change of the WCNC/CSNF coated strawberries decreased by nearly half compared with the control samples, showing coating effectiveness on preserving fruit freshness.
The postharvest phase has been considered a very suitable environment for successful application of biological control agents (BCAs) due to several parameters, such as temperature, oxygen composition and humidity that can be easily controlled. In addition, the knowledge of the main modes of action of BCAs is essential in order to enhance their viability and increase their potentiality in disease control to determining their successful activity. The antagonists display a wide range of modes of action: antibiosis, competition for nutrients and space, parasitism and induction of resistance, considered the main ones. Their efficacy, however, is related to the host and the pathogen; sometimes, different modes act simultaneously, and it is therefore difficult to establish which individual mechanism has contributed to a specific antifungal action.
Phytopathogenic association with beneficial microbiotic factors influences rhizospheric soil as well as plant growth parameters. Rhizospheric microbiotic factors check nutrients to supplement the lethal sensitivity against soilborne phytopathogens. All microbes besides harming plant growth are also able to reduce or check infection or disease caused by phytopathogens. Each microorganism showed specific antagonistic mechanisms against specific phytopathogens. This chapter discussed the importance of nematodes belonging to order Aphelenchida and Tylenchida which proved to be good management model organisms to inhibit or kill phytopathogens just like plant growth, promoting bacteria and fungi. Beneficial microbes protect plants from a greater extension of damage and induced plant vigor, growth, and development. Besides the beneficial role of microbiotic factors interacting with plants against soilborne phytopathogens present in soil ecology, it can also helps to develop products for agricultural biotechnology, biofertilizers, plant strengtheners, phytostimulation, and biopesticides. This chapter appraises the importance of microbiota factors and their mechanisms against soilborne phytopathogens.
The infection of fruit by the fungus Penicillin expansum, especially apples and derived products, is a serious global problem. Contaminated fruit and products not only threaten human health, but also reduce commercial profits. Given the potential hazards of synthetic fungicides, regulatory agencies have issued restrictions and even prohibitions on their commercial use. Therefore, the development of more environmentally friendly and safe postharvest P. expansum infection control is receiving increasing attention from researchers worldwide. This review summarizes and discusses studies on P. expansum from the past decade, including its contamination of fruit and postharvest control methods, and the contamination and synthesis of patulin, one of the main toxins produced by P. expansum. The combination of biological fungal control with physical or chemical control methods is highlighted. In practical applications, the simultaneous use of two or three of these methods, especially biological methods, achieves more stable and synergistic antifungal effects, and further research on the optimal commercial procedures for using these treatments would be potentially beneficial.
Many post-harvest diseases are caused by wound pathogens, and the complete control of these agents is done through the use of an agent which grows rapidly and is environmental friendly. One of the commonly used agents in regulating post-harvest diseases is a polysaccharide called chitosan. It is a common polysaccharide mostly found in crustaceans shells and fungi cell wall. It is mainly produced by the deacetylation of chitin. A great number of researches are being done on chitosan to know its mode of action. Chitosan has been proven to have various effects on plants, bacteria, viruses, and fungi. This review is to provide the different studies which have been done to control post-harvest diseases and to get a full understanding on how chitosan works.
As sustainable agriculture becomes more urgent, biocontrol using natural compounds such as chitin, a carbohydrate chain polymer, and its derivatives, is a promising strategy. Chitin and its derivatives induce or enhance natural defensive mechanisms in plants. They are recognized as plant growth regulators, growth stimulants, and elicitors for the production of secondary metabolites. They have beneficial effects as fertilizers, soil conditioning agents, plant disease control agents, antitranspirants, ripening retardants, and seed and fruit coatings.
Background
Produce are susceptible to microbial attack from diverse sources and the use of novel BCAs has gained recognition as alternative and sustainable applications to lessen the current emerging problems with synthetic fungicide use. Most researchers recommend the combination of two or more biocontrol agents in postharvest diseases control. To this end, the enhancement of biocontrol agents and the mechanisms of action in biocontrol systems have attracted many research interests. In this regard, there have been remarkable efforts to develop a multifaceted system approach for disease control.
Scope and approach
It has been recognized that the various methods of biological control act together additively or synergistically to achieve significant commercial level of 97–99% disease control. The integration of microbial agents with a wide range of unconventional chemicals and their corresponding mechanisms of action to controlling postharvest fungal pathogens of fruits has been proven be successful.
Key findings and conclusions
In this review, the combined strategy of unconventional chemical compounds and other BCAs have contributed to varied degree of postharvest diseases control. The beneficial effects of these methods depend on the appropriate combination of the agents based on adequate knowledge of their mechanisms of action in the biocontrol system. Lastly, efforts to upscale these methods to commercial implementation level must be given the necessary consideration.
Today some fruit juices such as apple juice are processed clear in most of the countries.
Production of clear and stable apple juice in beverage and fruit juice industries is an important
object and clarification is an important step in the processing of fruit juices. The aim of this
work was to investigate the clarification of apple juice with commercial acid soluble chitosan
and to find out the best chitosan concentration as a clarifying aid and also to improve the
apple juice color, titrable acidity, pH and soluble solids, and also the best reaction
temperature. Apples of Golden Delicious variety were used. Clarification was performed by
addition of soluble chitosan to apple juice at temperatures 35, 40 and 45˚C for 2 hrs. Chitosan
solutions with medium molecular weight at concentrations 0/1, 0/5, 0/7, 1, 1/5, 2, 2/5 and 3g/l
were used. The results showed that the clarity of apple juice was increased with increasing
chitosan concentration. So that the sample with chitosan treatment at 0.7g/l and 40˚C reached
maximum clarity. Also use of chitosan improved the color of apple juice. The a-values
(redness) and b-values (yellowness) were decreased with increasing L-values (brightness) and
chitosan treatment with 0/5g/l and 0/7g/l resulted in higher clarity. Addition of chitosan at
higher concentrations to apple juice reduced titrable acidity and increased pH values. Also
increasing chitosan concentration had relative effect on apple juice brix
Key Words: Chitosan, Apple juice, Clarification, Color
The excessive use of pesticides to prevent the outbreak of plant diseases
holds various disadvantages for the cost-effectiveness of agricultural production practices,
the quality of the end products, the environment and the labour force. The mounting
public resistance to the use of hazardous pesticides on agricultural crops has hastened
the search for natural antimicrobial peptides, enzymes and other types of biological control
agents. The objective of this study was to investigate the potential of the antifungal
activity of a yeast-derived chitinase for possible future agricultural applications. When
plants are exposed to fungal pathogens, they produce pathogenesis-related (PR) defence
proteins, such as chitinases, in order to degrade the chitin in the cell walls of the attacking
fungi, thereby inhibiting further fungal growth and the development of hyphae. We
have cloned the Saccharomyces cerevisiae chitinase gene (CTS1-2) into a multicopy
2μ-based plasmid and overexpressed it under the control of the phosphoglycerate kinase
I gene (PGK1) promoter (PGK1P) and terminator (PGK1T) sequences. Secretion of the
recombinant CTS1-2-encoded chitinases was directed by the native leader peptide, or by
the secretion signals of either the yeast mating pheromone α-factor (MFα1S) or the Trichoderma
reesei β-xylanase 2 (XYN2S). Northern blot analysis confirmed the PGK1PTdirected
expression of CTS1-2 and an indirect enzyme assay was used to compare the
efficiency of secretion of the three different recombinant chitinases. These recombinant
chitinases were also shown to effectively inhibit spore germination and hyphal growth of
Botrytis cinerea, an economically important fungal pathogen of several agricultural crop
plants, including grapevine. This study could lead to the development of yeast chitinases
and/or chitinolytic yeasts as biocontrol agents to combat plant diseases and reduce the
use of chemical pesticides in the agricultural industry.
Fungal plant diseases are one of the major concerns to agricultural food production world wide. Soil borne pathogenic fungi such as Pythium, Fusarium, Rhizoctonia and Phytopthora attack most of the economically important crop plants (either through seed root before germination or seedling after germination) resulting in loss of billions of dollars. Moreover, the management of chitinous waste is also pressing need today. Mycolytic enzymes (chitinases, proteases and glucanase) producing microorganisms may help in solving these problems. These microorganisms have ability to lyse the fungal cell wall and also have the potential to manage the chitinous waste by producing chitinases. Many chitinolytic microorganisms have potential to control fungal plant pathogens but they are not fully successful in all the cases due to different geological and environmental conditions. Thus, bioprospecting to find novel, highly chitinolytic microorganisms which help in developing potential biocontrol agent. Furthermore, to increase the survivability of biocontrol agents, a formulation may also be necessary. This review is focused on the progress of chitinase genes, chitinolytic microorganisms and their diversity as well as formulation of chitinolytic producers which have the potential to control fungal plant pathogens
The production of antibacterial compounds by yeasts and yeastlike fungi isolated from the phylloplane is reported. Aureobasidium pullulans, Citeromyces matritensis, Cryptococcus laurentii, Rhodotorula glutinis, and Sporobolomyces roseus produced antibacterial compounds inhibitory to both Pseudomonas fluorescens and Staphylococcus aureus in an overlay bioassay. In contrast, isolates of Candida albicans, Filobasidium uniguttulatum, Saccharomyces cerevisiae, Torulaspora delbruckii, Tremella foliacea, Trichosporon beigelii, and Trichosporon dulcitum obtained from soil or from culture collections did not produce inhibitory compounds when screened by the same procedure. The production of antibacterial compounds was examined in more detail, using several isolates of A. pullulans distinguished by cluster analysis on the basis of biochemical and physiological tests. They were found to produce a range of antibacterial compounds with different activities. Two distinct antibiotics were produced by an isolate of A. pullulans in liquid culture during both the logarithmic and the stationary phases of growth.
Losses from postharvest fruit diseases range from 1 to 20 percent in the United States, depending on the commodity. The application of fungicides to fruits after harvest to reduce decay has been increasingly curtailed by the development of pathogen resistance to many key fungicides, the lack of replacement fungicides, negative public perception regarding the safety of pesticides and consequent restrictions on fungicide use. Biological control of postharvest diseases (BCPD) has emerged as an effective alternative. Because wound-invading necrotrophic pathogens are vulnerable to biocontrol, antagonists can be applied directly to the targeted area (fruit wounds), and a single application using existing delivery systems (drenches, line sprayers, on-line dips) can significantly reduce fruit decays. The pioneering biocontrol products BioSave and Aspire were registered by EPA in 1995 for control of postharvest rots of pome and citrus fruit, respectively, and are commercially available. The limitations of these biocontrol products can be addressed by enhancing biocontrol through manipulation of the environment, using mixtures of beneficial organisms, physiological and genetic enhancement of the biocontrol mechanisms, manipulation of formulations, and integration of biocontrol with other alternative methods that alone do not provide adequate protection but in combination with biocontrol provide additive or synergistic effects.
The Saccharomyces cerevisiae chitinase, encoded by the CTS1-2 gene has recently been confirmed by in vitro tests to possess antifungal abilities. In this study, the CTS1-2 gene has been evaluated for its in planta antifungal activity by constitutive overexpression in tobacco plants to assess its potential to increase the plant's defence against fungal pathogens. Transgenic tobacco plants, generated by Agrobacterium-mediated transformation, showed stable integration and inheritance of the transgene. Northern blot analyses conducted on the transgenic tobacco plants confirmed transgene expression. Leaf extracts from the transgenic lines inhibited Botrytis cinerea spore germination and hyphal growth by up to 70% in a quantitative in vitro assay, leading to severe physical damage on the hyphae. Several of the F1 progeny lines were challenged with the fungal pathogen, B. cinerea, in a detached leaf infection assay, showing a decrease in susceptibility ranging from 50 to 70%. The plant lines that showed increased disease tolerance were also shown to have higher chitinase activities.
The yeast Candida oleophila, the base of the commercial product Aspire, is recommended for the control of postharvest decay of citrus and pome fruit. Competition for nutrients and space is believed to be the major mode of action. Involvement of fungal cell wall-degrading enzymes is also suggested to play a role in the mechanism of action of yeast antagonists. The present study showed that the yeast C. oleophila is capable of producing and secreting various cell wall-degrading enzymes, including exo-beta-1,3-glucanase, chitinase and protease. Exo-beta-1,3-glucanase and chitinase were produced and maximized in the early stages of growth, whereas protease reached a maximum level only after 6-8 days. Production of exo-beta-1,3-glucanase, chitinase and protease was stimulated by the presence of cell wall fragments of Penicillium digitatum in the growth medium, in addition to glucose. This study also provided evidence that C. oleophila is capable of secreting exo-beta-1,3-glucanase into the wounded surface of grapefruit. The role of exo-beta-1,3-glucanase ( CoEXG1) in the biocontrol activity of C. oleophila was tested using CoEXG1-knockouts and double- CoEXG1 over-producing transformants. In vitro bioassays showed that wild-type C. oleophila and exo-beta-1,3-glucanase over-expressing transformants had similar inhibitory effects on spore germination and germ-tube elongation; and both were more inhibitory to the fungus than the knockout transformant. In experiments conducted on fruit to test the biocontrol activity against infection by P. digitatum, no significant difference in inhibition was observed between transformants and untransformed C. oleophila cells at the high concentrations of cells used, whereas at a lower concentration of yeast cells the knockout transformants appeared to be less effective.
World trends are moving towards reduced pesticide use in fresh fruit and vegetables. Along with this trend, several physical and biological means have been evaluated as safer alternatives for the use of chemical fungicides. The use of microbial antagonists for the control of postharvest diseases received special attention, and has been extensively investigated. Most of the reported yeast and bacteria antagonists were naturally occurring on fruit surfaces. Microbial biocontrol agents of postharvest diseases have been criticized mainly for not providing as consistent or broad-spectrum control as synthetic fungicides. The "first generation" of biological controls for postharvest spoilage relied on the use of single antagonists. Perhaps it is unrealistic for us to expect disease control comparable to synthetic fungicides by the use of single antagonists. It can be expected that enhancing efficacy of biocontrol agents of postharvest diseases to an acceptable level will utilize a combination of different biological and physical means. As we learn more about the fundamental basis underlying the protective effect of microbial antagonists, bioactive compounds, and induced resistance, more effective methods of formulating, applying and combining complementary biological approaches for additive and/or synergistic effects will emerge. So far the results obtained with the different combinations of biological chemical and physical means demonstrate the potential of this multifaceted approach as a viable alternative to synthetic fungicides.
World trends are moving towards reduced pesticide use in fresh fruit and vegetables. Along with this trend, several physical and biological means have been evaluated as safer alternatives for the use of chemical fungicides. The use of microbial antagonists for the control of postharvest diseases received special attention, and has been extensively investigated. Most of the reported yeast and bacteria antagonists were naturally occurring on fruit surfaces. Microbial biocontrol agents of postharvest diseases have been criticized mainly for not providing as consistent or broad-spectrum control as synthetic fungicides. The "first generation" of biological controls for postharvest spoilage relied on the use of single antagonists. Perhaps it is unrealistic for us to expect disease control comparable to synthetic fungicides by the use of single antagonists. It can be expected that enhancing efficacy of biocontrol agents of postharvest diseases to an acceptable level will utilize a combination of different biological and physical means. As we learn more about the fundamental basis underlying the protective effect of microbial antagonists, bioactive compounds, and induced resistance, more effective methods of formulating, applying and combining complementary biological approaches for additive and/or synergistic effects will emerge. So far the results obtained with the different combinations of biological chemical and physical means demonstrate the potential of this multifaceted approach as a viable alternative to synthetic fungicides.
Chitin applied as an amendment to peanut leaves increased the populations of indigenous chitinolytic epiphytes from <1% to >40% of the total microflora. The total epiphytic bacterial populations increased by up to 0.3 log with the addition of chitin. When the chitinolytic Bacillus cereus strain 304 isolated from chitin-amended leaves was reapplied to peanut foliage with chitin, its populations were sustained as actively growing vegetative cells for a longer period than when applied to nonamended leaves. Eight days after application, B. cereus populations were > 1 log higher on chitin-amended leaves than on nonamended leaves. In two of three field trials, significant reductions in the severity of early leafspot caused by Cercospora arachidicola were seen on chitin-amended leaves, and a trend toward additional control (P < 0.10) was obtained on leaves treated with chitin plus the chitinolytic B. cereus. Scanning electron microscopy revealed chitin deposits, fungal hyphae, and spores colonized by bacilliform bacteria. Colonized fungal hyphae and spores were pitted and distorted, indicating a potential for biological control of chitin-containing fungal pathogens by chitinolytic bacterial antagonists.
Control of blue mold decay in Bose pears was studied with the laboratory-grown yeasts Rhodotorula glutinis, Cryptococcus infirmo-miniatus, and two strains off Cryptococcus laurentii, as well as registered biocontrol products Aspire, containing the yeast Candida oleophila, and Bio-Save 11 (now Bio-Save 110), containing the bacterium Pseudomonas syringae. Both thiabendazole (TBZ)-sensitive and TBZ-resistant strains of Penicillium expansum were used. Aspire treatment reduced the average lesion diameter by approximately 65 and 45%, and reduced decay incidence by 27 and 9% with TBZ-resistant and TBZ-sensitive expansum, respectively in the first year of the study, but did not result in significant decay control in the second year. Bio-Save 11 reduced decay lesion,diameter by 32 to 72% and incidence by 21 to 40% over the 2 years. In both years, TBZ-sensitive P. expansum was completely controlled by the combination of either C. laurentii (both strains), A. glutinis, or C. infirmo-miniatus with 100 ppm TBZ. With TBZ-resistant P. expansum, control of wound infection with these yeasts alone or with 100 ppm TBZ ranged from 62.9 to 100%. In a packinghouse trial, control by Bio-Save 110 + 100 ppm TBZ and Aspire + 100 ppm TBZ was not different than control by TBZ at 569 ppm, the maximum label rate. The amount of decay following Aspire + 100 ppm TBZ treatment was significantly less than the amount of decay following Bio-Save 110 + 100 ppm TBZ treatment.
The effects of chitin and chitosan on disease incidence and severity of Fusarium yellows of celery and on populations of Fusarium oxysporum were investigated between 1994 and 1996. Field experiments were conducted at two locations with a history of severe Fusarium yellows. Disease incidence and severity were significantly reduced by pre-plant chitin amendments to soil. Chitosan applied as a root dip alone did not reduce disease incidence but significantly (P < 0.05) reduced disease severity when used with a tolerant celery cultivar. Standard soil dilution methods were used to enumerate populations of soil microflora. Chitin increased bacterial and actinomycete populations in soil in 2 of the 3 years of study. The effects of potential biocontrol agents recovered from chitin-treated plots in 1995 were studied in 1996; enriching the transplant medium with isolates of bacteria and actinomycetes 4 weeks and 1 week prior to transplanting did not alter the established equilibrium in the field, and no biocontrol effect was observed. Chitin amendments to soil or chitosan treatment of transplants did not reduce soil populations of F. oxysporum. Whether these treatments affected the F. oxysporum f. sp. apii subpopulation within the E oxysporum population could not be determined.
Treatment of wounds with washed cells of C. laurentii at 10 4 -10 5 cells per wound effectively reduced or prevented development of decay by Botrytis cinerea at all temperatures compared with controls and was comparable in effectiveness to preinoculation application of benomyl at the postharvest label rate. Treatment of wounds with cell-free culture filtrates of C. laurentii were not effective in preventing decay and resulted in greater lesion diameters than in inoculated, buffer-treated wounds
The yeasts, Cryptococcus laurentii BSR-Y22 or Sporobolomyces roseus FS-43-238, but not Saccharomyces cerevisiae BY-1, reduced gray mold ( Botrytis cinerea ) when applied to wounds of apples (cv. Golden Delicious) which were stored at 22IC for 7 days or 3IC for up to 2 months. The role of competition for sugars by these yeasts as a mechanism of antagonism was investigated at 22IC. Populations of C. laurentii and S. roseus in wounds were 6-9 times greater than those of S. cerevisiae from 1 to 7 days following inoculation. Yeasts in wounds utilized more 14C-labelled fructose, glucose or sucrose than conidia of B. cinerea during 48 h, but yeasts did not differ in their utilization of sugars. Utilization of 14C-sugars by yeasts in vitro was greater at most sampling times for conidia; the uptake after 48 h was always greater for yeasts and the addition of nitrogen did not alter this result. The utilization of 14C-sugars by S. roseus in vitro was greater than that in the other yeasts. The uptake and utilization of 14C-fructose by C. laurentii or S. roseus was greater than that of S. cerevisiae , but the utilization of glucose or sucrose by C. laurentii and S. cerevisiae was similar and the uptake of these sugars by these yeasts did not differ. Yeasts mixed with conidia in sterile, dilute solutions of fructose, glucose or sucrose, or in dilute apple juice inhibited conidial germination compared with no-yeast controls; S. cerevisiae was less effective than C. laurentii or S. roseus . Only yeasts rapidly depleted sugars from juice or sugar solutions. Yeasts did not alter the pH or oxygen content of dilute juice to the detriment of conidial germination. These results strongly suggest that competition for sugars by yeasts played a role in the biocontrol of gray mold, but that some other factor(s) most likely contributed to differences in efficacy between the yeasts.
Candida guilliermondii (strains 101 and US 7) and C. oleophila (strain I-182) were screened for biocontrol activity (BA) against Botrytis cinerea, both in vitro and in a bioassay, using stem portions and atomized aqueous pathogen suspensions. Yeast C. guilliermondii strains 101 and US 7 significantly reduced disease incidence, when applied simultaneously with the pathogen, whereas C. oleophila strain I-182 and isolated epiphytic yeasts had no BA against B. cinerea. When tomato stem portions were inoculated with yeasts (strains 101 and US 7) 24h before pathogen challenge, the BA significantly improved. Addition of exogenous nutrients significantly reduced BA of both yeast strains, indicating that nutrient competition may be involved in their mode of action. In vivo application of both C. oleophila (strain I-182) and C. guilliermondii (strains 101 and US 7) gave significant control of B. cinerea, even though strain I-182 had been ineffective in the stem assay. These results suggest that yeasts selected for the biocontrol of postharvest diseases have the potential to control diseases of whole plants.
Cryptococcus laurentii was evaluated for its activity in reducing postharvest gray mold decay of pear caused by Botrytis cinerea. Washed cell suspensions of yeast controlled gray mold better than yeast in culture broth. Treatment of wounds with autoclaved cell cultures or cell-free culture filtrate did not prevent decay. The interval between inoculation with the pathogen and application of the antagonist significantly influenced the efficacy of biocontrol. Efficacy was maintained when C. laurentii was applied simultaneously or prior to inoculation with B. cinerea but reduced if applied after inoculation with B. cinerea. The concentrations of antagonist had significant effects on biocontrol effectiveness: the higher the concentrations of the antagonist, the lower the disease incidence and the smaller the lesion diameter regardless of whether the fruit was stored at 25°C for 7 days or 2°C for 30 days followed by 20°C for 7 days. The efficacy of C. laurentii was enhanced by the addition of 2% CaCl2. C. laurentii significantly reduced the natural development of decay and did not impair quality parameters of fruit following storage at 2°C for 60 days followed by 20°C for 15 days.
Cryptococcus laurentii was evaluated for its activity in reducing postharvest gray mold decay, blue mold decay and Rhizopus decay of peach caused by Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer respectively, and in reducing natural decay development of peach fruits. The concentrations of antagonist had significant effects on biocontrol effectiveness: the higher the concentrations of the antagonist, the lower the disease incidence. At concentrations of C. laurentii at 1×109CFUml−1, the gray mold decay was completely inhibited after 4 days incubation at 25°C, while the control fruit had 50% decay, when inoculated with B. cinerea spores suspension of 1×105sporesml−1; no complete control of the blue mold or Rhizopus mold was observed, when peach fruits were stored at 25°C for 4days (challenged with P. expansum) or 5days (challenged with R. stolonifer) respectively, but the decay was distinctly prevented, the incidence of blue mold or Rhizopus mold was reduced by 78.6% or 80% respectively, compared with control, at challenged with P. expansum or R. stolonifer spores suspension of 5×104sporesml−1, respectively. C. laurentii significantly reduced the natural development of decay and did not impair quality parameters of fruit following storage at 2°C for 30days followed by 20°C for 7days.
Fungal plant diseases are one of the major concerns to agricultural food production world wide. Soil borne pathogenic fungi such as Pythium, Fusarium, Rhizoctonia and Phytopthora attack most of the economically important crop plants (either through seed root before germination or seedling after germination) resulting in loss of billions of dollars. Moreover, the management of chitinous waste is also pressing need today. Mycolytic enzymes (chitinases, proteases and glucanase) producing microorganisms may help in solving these problems. These microorganisms have ability to lyse the fungal cell wall and also have the potential to manage the chitinous waste by producing chitinases. Many chitinolytic microorganisms have potential to control fungal plant pathogens but they are not fully successful in all the cases due to different geological and environmental conditions. Thus, bioprospecting to find novel, highly chitinolytic microorganisms which help in developing potential biocontrol agent. Furthermore, to increase the survivability of biocontrol agents, a formulation may also be necessary. This review is focused on the progress of chitinase genes, chitinolytic microorganisms and their diversity as well as formulation of chitinolytic producers which have the potential to control fungal plant pathogens.
Talc-based bioformulations containing cells of Pseudomonas fluorescens, Bacillus subtilis and Saccharomyces cerevisiae were evaluated for their potential to attack the mango (Mangifera indica L.) anthracnose pathogen Colletotrichum gloeosporioides Penz. under endemic conditions. The preharvest aerial spray was given at fortnightly and monthly intervals. The plant growth-promoting
rhizobacteria Pseudomonas fluorescens (FP7) amended with chitin sprayed at fortnightly intervals gave the maximum induction of flowering, a yield attribute in
the preharvest stage, consequently reduced latent symptoms were recorded at the postharvest stage. An enormous induction of
the defence-mediating lytic enzymes chitinase and β-1,3-glucanase was recorded in colorimetric assay and the expression of
discrete bands in native PAGE analysis after FP7 + chitin treatment. The enhanced expression of defence-mediating enzymes
may collectively contribute to suppress the anthracnose pathogen, leading to improved yield attributes.
Pichia membranefaciens Hansen and Candida guilliermondii (Cast) Langeronet Guerra are two antagonists of R. stolonifer on harvested nectarine and peach fruits. In this study, β-1,3-glucanase and chitinase activities of the antagonists were
induced in vitro and in vivo. The highest β-1, 3-glucanase activity was detected in Lilly-Barnett minimal salt medium supplemented with glucose in combination
with CWP of R. stolonifer as a carbon source. The β-1,3-glucanase activity of P. membranefaciens reached the maximum level, being 114.0 SU (specific activity unit), and that of C. guilliermondii reached 103.2 SU. The lowest β-1,3-glucanase activity was observed in the medium containing glucose as sole carbon source.
P. membranefaciens was able to produce significantly higher levels of chitinase (exochitinase and endochitinase) in vitro than C. guilliermondii grown in Czapeck minimal medium. An increase in β-1,3-glucanase and chitinase activity was also triggered by wounding, adding
of carbon sources and yeast cells. The results showed that both β-1,3-glucanase and chitinase from P. membranefaciens and C. guilliermondii exhibited some effects on controlling R. stolonifer, and might have a synergistic activity against R. stolonifer.
Use of natural biopolymers for diversified applications in life sciences has several advantages, such as availability from replenishable agricultural or marine food resources, biocompatibility, biodegradability, therefore leading to ecological safety and the possibility of preparing a variety of chemically or enzymatically modified derivatives for specific end uses. Polysaccharides, as a class of natural macromolecules, have the tendency to be extremely bioactive, and are generally derived from agricultural feedstock or crustacean shell wastes. Cellulose, starch, pectin, etc. are the biopolymers derived from the former while chitin and chitosan are obtained from the latter. In terms of availability, chitin is next to cellulose, available to the extent of over 10 gigatons annually. The application potential of chitosan, a deacetylated derivative of chitin, is multidimensional, such as in food and nutrition, biotechnology, material science, drugs and pharmaceuticals, agriculture and environmental protection, and recently in gene therapy too. The net cationicity as well as the presence of multiple reactive functional groups in the molecule make chitosan a sought-after biomolecule. The latter offers scope for manipulation for preparing a broad spectrum of derivatives for specific end use applications in diversified areas. The biomedical and therapeutic significance of chitin/chitosan derivatives is a subject of significant concern to many all over the world. An attempt is made in this overview to consolidate some of the recent findings on the biorelated application potential of chitosan and its derivatives.
The talc based formulation of plant growth promoting rhizobacteria (PGPR) and yeast antagonistic strains with or without chitin amendment was evaluated against anthracnose in mango. A preharvest application of Pseudomonas fluorescens (FP7) with chitin formulation at monthly spray intervals through aerial spray significantly reduced the pre and postharvest anthracnose incidence. The strain FP7 containing chitin treated mango tree revealed the maximum panicle initiation and yield attributes. In field trials, P. fluorescens (FP7)+chitin treatment reduced the anthracnose incidence of 60% over untreated control and its efficacy was superior to standard fungicide carbendazim treatment. The reduced latent symptom expression was noticed in stored conditions.
The interactions between two antagonistic yeasts (Pichia membranefaciens and Cryptococcus albidus) and three fungal pathogens (Monilinia fructicola, Penicillium expansum and Rhizopus stolonifer) were examined both on apple juice agar plates and in apple wounds. Light microscopy and scanning electron microscopy (SEM) observations indicated that P. membranefaciens had a stronger capability of attaching to the fungal hyphae than C. albidus did. The attachment was blocked thoroughly by SDS and β-mercaptoethanol. Addition of nutrients had no visible effect on the interaction between yeasts and pathogens. Culture extract of P. membranefaciens had higher β-1,3-glucanase and exo-chitinase but less endo-chitinase activity than that of C. albidus in Lilly–Barnett medium supplied with cell wall preparation (CWP) of pathogens as the sole carbon source. This indicated that tenacious attachment, along with the secretion of extracellular lytic enzymes, may play a role in the biocontrol activity of yeast antagonists, and the interaction between yeasts and pathogens was hampered by a protein denaturant at low concentrations.
The secretion of hydrolytic enzymes by yeasts was studied in batch cultures amended with different carbon sources (glucose, laminarin, and Botrytis cinerea cell wall preparation). Candida guilliermondii (strains 101 and US 7) and Candida oleophila (strain I-182) secreted detectable amounts of (β-1,3-exoglucanase and chitinase at environmentally relevant temperatures and in all carbon sources. Secretion was carbon source dependent with glucose inducing the production of the highest amount, followed by laminarin and B. cinerea cell wall preparation. In many cases, C. oleophila demonstrated the highest hydrolytic enzyme secretion. However, it was observed that the enzymes may constitute a relatively small part of the total protein secreted. The possibility that other products may be involved is discussed. Studies on population dynamics of all three yeasts on stems revealed a 10-fold increase in the number of viable yeast cells within the first 48 h after inoculation, followed by a persistent high level of viable cells for 15 days. In an assay, in which yeasts and B. cinerea spores were separated by Cellophane, yeasts significantly reduced germ tube length especially when Cellophane was overlaid on cut stems of tomato inoculated with yeasts. None of the isolates studied induced the production of diffusible antifungal compounds (phytoalexins) in a leaf bioassay. However, B. cinerea induced the production of such compounds, and significantly reduced B. cinerea spore germination but not germ tube elongation. All three yeast strains, both dead and living yeast cells, were shown to adhere to the B. cinerea hyphae, while an inactive control strain did not.
ABSTRACT Unmodified and low water activity (a(w))-tolerant cells of Candida sake CPA-1 applied before harvest were compared for ability to control blue mold of apples ('Golden Delicious') caused by Penicillium expansum under commercial storage conditions. The population dynamics of strain CPA-1 on apples were studied in the orchard and during storage following application of 3 x 10(6) CFU/ml of each treatment 2 days prior to harvest. In the field, the population size of the unmodified treatment remained relatively unchanged, while the population size of the low-a(w)-modified CPA-1 cells increased. During cold storage, the populations in both treatments increased from 10(3) to 10(5) CFU/g of apple after 30 days, and then declined to about 2.5 x 10(4) CFU/g of apple. In laboratory studies, the low-a(w)-tolerant cells provided significantly better disease control as compared with the unmodified cells and reduced the number of infected wounds and lesion size by 75 and 90%, respectively, as compared with the non-treated controls. After 4 months in cold storage, both unmodified and low-a(w)-tolerant cells of C. sake were equally effective against P. expansum on apple (>50% reduction in size of infected wounds).
The properties and applications of chitin and its derivatives for its utilization in the food industry are described. The progress of industrial chitin and chitosan processing depends on the utilization of microbial sources of these polysaccharides, which can be available in the desired amount from cultures cultivated on an inexpensive media. Enzymatic procedures for deproteinization of the shells or mold mycelia and for chitin deacetylation are also studied. The results show that the chitin is resistant to enzymatic deacetylation.
Although the number of biocontrol products is increasing, these products still represent only about 1% of agricultural chemical sales. Yet these are important contributions because biocontrol agents offer disease management alternatives with different mechanisms of action than chemical pesticides. Trends in research include the increased use of biorational screening processes to identify microorganisms with potential for biocontrol, increased testing under semicommercial and commercial production conditions, increased emphasis on combining biocontrol strains with each other and with other control methods, integrating biocontrol into an overall system.
Chitin and chitinases (EC 3.2.1.14) have an immense potential. Chitinolytic enzymes have wide-ranging applications such as preparation of pharmaceutically important chitooligosaccharides and N-acetyl D-glucosamine, preparation of single-cell protein, isolation of protoplasts from fungi and yeast, control of pathogenic fungi, treatment of chitinous waste, and control of malaria transmission. In this review, we discuss the occurrence and structure of chitin, the types and sources of chitinases, their mode of action, chitinase production, as well as molecular cloning and protein engineering of chitinases and their biotechnological applications.
The objective of this study was to investigate the extracellular enzymatic activity (EEA) profile of yeasts isolated from tropical environments of the Brazilian rain forest. This screening survey could constitute the first approach in selecting yeast strains of environmental origin potentially exploitable as enzyme producers.
In this study, 348 yeast (193 ascomycetes and 155 basidiomycetes) and 46 yeast-like strains (Aureobasidium pullulans) were screened for their EEA profile. The spread occurrence of extracellular amylases, esterases, lipases, proteases, pectinases and chitinases appeared to be a strain-related character.
Yeasts isolated from tropical environments could represent a promising source of EEA. Selected strains showed maximum levels of EEA under acidic or neutral conditions.
This study demonstrated the potential for yeasts isolated from extreme environments as sources of industrially relevant enzymes for biotechnological purposes.
To investigate the effects of internal trehalose on viability and biocontrol efficacy of antagonistic yeast Cryptococcus laurentii under stresses of low temperature (LT), controlled atmosphere (CA) and freeze drying.
The content of trehalose in C. laurentii was increased by culturing the yeast in trehalose-containing medium. Compared with yeast cells with low trehalose level, the yeast cells with high level of internal trehalose not only obtained higher viability, but also showed higher population and better biocontrol efficacy against Penicillium expansum on apple fruit both at 1 degrees C and in CA condition (5% O(2), 5% CO(2), 1 degrees C). After freeze drying, survival of the yeast with high trehalose level was markedly increased when stored at 25 degrees C for 0, 15 and 30 days. Meanwhile, high integrity of plasma membrane was detected in the freeze-dried yeast with high trehalose level by propidium iodide staining.
Induced accumulation of internal trehalose could improve viability and biocontrol efficacy of C. laurentii under stresses of LT and CA. Moreover, survival of the yeast was also increased as internal trehalose accumulation after freeze drying, and one of the reasons might be that trehalose gave an effective protection to plasma membrane.
The results of this experiment show a promising way to improve the biocontrol performance of antagonistic yeasts under the commercial conditions.
Chitin is the second most abundant organic and renewable source in nature, after cellulose. Chitinases are chitin-degrading enzymes. Chitinases have important biophysiological functions and immense potential applications. In recent years, researches on fungal chitinases have made fast progress, especially in molecular levels. Therefore, the present review will focus on recent advances of fungal chitinases, containing their nomenclature and assays, purification and characterization, molecular cloning and expression, family and structure, regulation, and function and application.
This study was conducted to determine the efficacy of chitosan at different concentrations with various intrinsic viscosities alone, and in its combination with a yeast antagonist Cryptococcus laurentii in reducing the blue mold rot caused by Penicillium expansum in apple fruit. The results indicated that application of chitosan alone was effective in inhibiting the blue mold rot in apple fruit wounds, especially with the high concentrations and low viscosities. But its efficacy was declining with the incubation time so that chitosan alone could not provide enduring protection of apple fruit from P. expansum infections. When applied at the concentration range from 0.001 to 0.1% (wt/vol), chitosan did not influence the population growth of C. laurentii in vivo, whereas it markedly repressed the yeast growth as its concentrations were increased up to 0.25% (wt/vol) or higher. Moreover, combination of chitosan and C. laurentii resulted in a synergistic inhibition of the blue mold rot, being the most effective at the optimal concentration of 0.1% of chitosan with the lowest viscosity (12 cP). The possible mode of action of the combination of chitosan and C. laurentii was discussed.