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Antagonistic potential of Trichoderma harzianum (TH), Gliocladium virens (GV) and T. viride (TV) dual cultured with Pythium ultimum, noted two days after incubation at 25 °C, as compared to pathogen-inoculated and untreated control.
Source publication
Pythium ultimum is common soilborne pathogen causing serious losses of pepper seedlings in nurseries and few weeks post-planting. Two pepper associated-P. ultimum isolates (P1 and P2) were shown pathogenic to pepper cv. Altar causing post-emergence damping-off with P2 isolate being the most aggressive. Fungal and bacterial antagonists have been eva...
Context in source publication
Context 1
... harzianum, T. viride, and G. virens reduced pathogen radial growth by 18.54, 17.52, and 15.24%, respectively, relative to the untreated control (Figure 2). Moreover, these antagonists grew and sporulated abundantly, invaded P. ultimum colonies and reach their opposite edge after six days of dual culture at 25 °C (Figure 3). Fungal treatment ...
Citations
... Recently, Elshahawy and El-Mohamedy (2019) reported that in the greenhouse experiment, the combined inoculation of five Trichoderma isolates suppressed dampingoff induced by P. aphanidermatum and increased the survival of tomato plants by 74.5%. A recent study in Tunisia showed that in dual culture assay, T. harzianum inhibited P. ultimum radial growth by 18.54% with drastic changes in pathogen hyphae expressed as strong lysis, formation of mycelial cords and mycoparasitism (Mannai et al. 2020). The evaluation of post-emergence dampingoff suppression ability proved that T. harzianum had significantly improved the pepper plant height by 22.22% over pathogen-inoculated and untreated control (Mannai et al. 2020). ...
... A recent study in Tunisia showed that in dual culture assay, T. harzianum inhibited P. ultimum radial growth by 18.54% with drastic changes in pathogen hyphae expressed as strong lysis, formation of mycelial cords and mycoparasitism (Mannai et al. 2020). The evaluation of post-emergence dampingoff suppression ability proved that T. harzianum had significantly improved the pepper plant height by 22.22% over pathogen-inoculated and untreated control (Mannai et al. 2020). The evaluation of pre-emergence damping-off suppression ability showed that pepper seeds treated with T. harzianum conidial suspensions gave 60% less pre-emergence damping-off infections caused by P. ultimum, compared to the positive control (Mannai et al. 2020). ...
... The evaluation of post-emergence dampingoff suppression ability proved that T. harzianum had significantly improved the pepper plant height by 22.22% over pathogen-inoculated and untreated control (Mannai et al. 2020). The evaluation of pre-emergence damping-off suppression ability showed that pepper seeds treated with T. harzianum conidial suspensions gave 60% less pre-emergence damping-off infections caused by P. ultimum, compared to the positive control (Mannai et al. 2020). In addition, the use of Trichoderma spp. in agriculture can offer many benefits such as colonization of the rhizosphere allowing rapid establishment in stable microbial communities of the rhizosphere, control of pathogens using various mechanisms, improving plant vigor and stimulating growth root (Harman et al. 2004). ...
Background
Apple decline diseases, responsible for seedlings root and collar rot in nurseries, are an important disease. Different fungal and bacterial antagonists were evaluated to control Pythium ultimum associated with this serious disease using in vitro and in vivo greenhouse assays.
Results
The in vitro test of ten Aspergillus spp. and ten Trichoderma harzianum isolates showed their efficacy to reduce the radial growth of P. ultimum . The isolates, A. niger A10, A. candidus A5, T. harzianum Tr9 and Tr10, were the most effective with a high inhibition percent that exceeded 50%. The in vivo test of the four most effective antagonists and a strain of Bacillus subtilis (B) showed that the combination of the two Aspergillus isolates (A5 and A10) gave the best result with a decrease in root browning index by 55.55%. Results showed also the efficacy of all tested antagonists and their combinations on the sanitary state index of the inoculated plants except the combination between T. harzianum (Tr10) and B. subtilis (B). The two treatments, T. harzianum (Tr10) and B. subtilis (B), significantly improved the height of inoculated plants by 173.19 and 191.3%, respectively. Regarding the efficacy of antagonists on apple seedlings root weight, A. niger (A10) was the only treatment that significantly increased this parameter by 363.17%.
Conclusions
A. niger A10, A. candidus A5, T. harzianum Tr9 and Tr10 exhibited the highest value of in vitro inhibition to growth of P. ultimum . The combination of A. niger A10 and A. candidus A5 was the most effective in vivo treatment in reducing the disease severity index. However, T. harzianum (Tr10), B. subtilis (B) and A. niger (A10) revealed to be able to stimulate the apple seedlings growth.
... Multiple techniques were applied to suppress Pythium and its induced damping-off diseases including chemical, physical and biological methods (Papavizas et al. 1977;Kassaby 1985;Knudsen et al. 2002;Mannai et al. 2020). Since chemical treatment which is a popular technique among the farmers has negative impacts especially for the environment, therefore, there was a real need for more bio-effective and biosafety mechanisms. ...
Damping-off diseases caused huge losses in crop production in numerous countries. Pythium aphanidermatum represents a major cause of these diseases. In the present investigation, two endophytic fungi Talaromyces omanensis and Aspergillus fumigatus isolated from a desert plant, Rhazya stricta, were investigated for their efficiency in suppressing P. aphanidermatum and its stimulated damping-off diseases in cucumber and radish. The results proved the ability of both endophytes to inhibit P. aphanidermatum growth in both solid and liquid forms, inhibit its oospore production, induce abnormal patterns in its hyphae and suppress its induced damping-off diseases. Moreover, T. omanensis produced an inhibition zone area against P. aphanidermatum and enhanced the fresh weight of cucumber and length, fresh weight and dry weight of radish. Further, A. fumigatus caused cellular leakage in P. aphanidermatum mycelium. The previous results were interpreted through the secretion of β-1,3-glucanase, cellulase and siderophore by both endophytic fungi.
... Trichoderma species are the most widely used antagonists for controlling plant diseases (Yassin et al. 2021). Several bacteria such as Bacillus, Pseudomonas, Burkholderia and Streptomyces species have been used to manage soilborne pathogens of many vegetable crops (Mannai et al. 2020). These species are capable of producing some bioactive secondary metabolites (Khan et al. 2020). ...
... These species are capable of producing some bioactive secondary metabolites (Khan et al. 2020). Several previous studies showed that these fungal and bacterial antagonists' species efficiently controlled Fusarium, Pythium and Phytophthora species pathogens associated with many crops (Mannai et al. 2020). A combinatory approach has also the potential to resolve problems that occur with individual biocontrol agents. ...
... In in vivo trials, pretreatment of cocoyam plants with 2 T. asperellum strains reduced P. myriotylum infection by 50% (Mbarga et al. 2012). Moreover, a recent study on the efficacy of T. harzianum and T. viride against Pythium dampingoff of pepper showed that these antagonists inhibited P. ultimum radial growth by 18.54, 17.52 %, respectively, in dual culture assay and reduced the pre-and postemergence pepper damping-off infections (Mannai et al. 2020). Besides, a study established in Saudi Arabia to evaluate the antagonistic efficacy of 2 species of Trichoderma against the most common causative agents of stalk rot disease of maize showed that Trichoderma viride was effective against F. proliferatum and F. verticillioides with mycelial inhibition rates of 80.17 and 70.46% and T. harzianum exhibited rates of 68.38 and 60.64%, respectively (Yassin et al. 2021). ...
Background
The effect of Aspergillus spp. and Trichoderma harzianum isolates was evaluated against the growth of Fusarium oxysporum , F. solani , Pythium ultimum and Phytophthora citrophthora affecting peach seedlings.
Results
The in vitro results revealed the ability of these antagonistic in reducing the radial growth of these pathogens. The most important mycelial growth reduction was of 85.82%, recorded for F. oxysporum in confrontation with A5 of Aspergillus candidus . Aspergillus flavus A4 and A. niger A10 were the most effective against F. solani with an inhibition percent more than 60%. For P. citrophthora , A. flavus A4, A. candidus A5, A. terreus A9 and A. niger A10 inhibited the mycelia growth by more than 60%. Aspergillus nidulans A1 was the most effective against Pythium ultimum (72.07%). Trichoderma harzianum isolates T9 and T10, are the most effective with a high inhibition percent of mycelial growth. The inhibition induced after 4 days of incubation, against F. oxysporum , F. solani , P. citrophthora and Pythium ultimum by these 2 antagonists exceeded 70, 60, 70 and 80%, respectively. The in planta test showed the efficacy of antagonists tested solo against some pathogens. In fact, Bacillus subtilis improved the health status by 62.55% compared to the control inoculated with P. ultimum . Trichoderma harzianum T9 significantly reduced the root rot index by 87.5% than the control inoculated with F. solani . In the same sense, B. subtilis significantly reduced this parameter by 62.55 and 88.89% than the control inoculated with P. ultimum and P. citrophthora , respectively. Furthermore, B. subtilis (B) and Aspergillus niger A10 improved plants height than the control inoculated with Pythium ultimum by 31.52 and 40.49%, respectively. However, the combinations of antagonists (T9 + T10; A5 + A10 and B + T10) did not improve their efficacy.
Conclusions
The isolates T. harzianum (T9 and T10), A. candidus A5 and A. niger A10 were the most effective in vitro against Fusarium , Pythium and Phytophthora species associated with peach seedling decline. The in vivo assay showed the effectiveness of B. subtilis against P. ultimum and P. citrophthora and the potential effect of T. harzianum T9 against F. solani. Their combinations revealed to be ineffective.
... Some fungi viz. Trichoderma harzianum, T. viride and Gliocladium virens control damping off caused by P. aphanidermatum and P. ultimum in pepper seedlings, showing improved seedling emergence and length up to 25% relative to control, respectively (Sivan et al. 1984;Lumsden and Locke 1989;Mannai et al. 2020). The rhizobacteria, P. aureofaciens, P. fluorescens, P. putida and B. pumilus have been shown to increase the length of the seedlings and biomass in pepper (Hahm et al. 2012). ...
Pepper is one of the most important spice crops in the world today with an enormous economic value. The pepper fruits are rich in pharmaceutically important compounds such as carotenoids and capsaicinoids. Over the years, crops of pepper have suffered significant losses in terms of yield and quality due to a myriad of pathogen infections including fungi, viruses and bacteria. More often, broad host ranges, novel pathogen strains and simultaneous infections due to multiple pathogens lead to resistance breakdown of host plants. An increased virulence of pathogens also results in exacerbated disease symptoms and yield losses. Coevolution of pathogens and crops allows them to harden each other’s defense responses, however the whole process remains skewed in favor of the pathogens. Genomic designing of Capsicum genotypes which are more resilient to the imminent threats of rapid climatic changes and biotic stresses is now the major focus of current research. Hence, it becomes critical to understand the pathogens and their pathogenic properties in details to incorporate this knowledge into future breeding programs on disease resistance. Traditional breeding programs have met with little success due to the polygenic control of resistance, wide variability in the pathogen range along with complex pathogenicity mechanisms. Marker-assisted selection allows indirect selection of desired resistance alleles in the early stages of life cycle of the plant. The development of resistant commercial pepper varieties and host plant resistance are the permanent, effective and eco-friendly substitutes to the chemical and physical control methods and cultural practices for management of various biotic stresses. The multiplicity of abiotic and biotic stresses are the warning signs to initiate serious and concerted efforts towards making the crops more resilient and resistant to these stresses and to achieve desired crop breeding goals. Present chapter assembles the recommendations, details of the resistance sources, genes, QTLs and other resources available to diminish the effects of different biotic stresses towards genetic improvement of Capsicum species with modern, time critical and scalable scientific methods.Keywords
Capsicum
FungiVirusBacteriaResistance genesQTLs
Capsicum (chili pepper) is a highly valued crop of the Solanaceae family desired for its characteristic sensory and culinary properties around the world. Capsicum fruits exhibit huge variations in the phenotypic traits, such as shape, size, color, texture, shelf life, and so on, that appeal directly to the consumer preference. The fruits of the Capsicum genus are also diversely rich in several health-benefitting bioactive compounds such as capsaicinoids (mainly capsaicin and dihydrocapsaicin), vitamins (C and E), carotenoids, antioxidants, flavonoids, and so on. Often, highly pungent and stress-resistant Capsicum varieties suit the breeders’ choice. In the past few years, pepper genetics, breeding, and improvement have made an unscalable amount of progress in terms of the characterization of genes and quantitative trait loci controlling plant- and fruit-related character traits, metabolites, and biotic and abiotic stress resistance complemented with marker-assisted selection and genetic manipulation. High-throughput methods like whole genome sequencing and transcriptome analyses have bridged the gap between genetic resources and molecular biology to develop highly competent pepper varieties. Furthermore, biotechnological advances have facilitated rapid transgene interrogation, target-based gene silencing, and overexpression for the functional characterization of candidate genes for the genetic improvement of the pepper crop.
