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A Novel Antifungal Furanone from Pseudomonas aureofaciens, a Biocontrol Agent of Fungal Plant Pathogens
Abstract and Figures
Pseudomonas aureofaciens (= P. chlororaphis) strain 63-28 is a biocontrol agent active against many soil-borne fungal plant pathogens and shows antifungal activity in culture assays. 3-(1-Hexenyl)-5-methyl-2-(5H)furanone was isolated from culture filtrates of this bacterium. The purified furanone showed antifungal activity against Pythium ultimum, Fusarium solani, Fusarium oxysporum, and Thielaviopsis basicola. The ED50S for spore germination of these fungi were 45, 54, 56, and 25 g/ml, respectively. The compound also inhibited the germ tube growth of Rhizoctonia solani growing from microsclerotia, with an ED50 of 61 g/ml. The compound is the reduced form of furanones previously described from this bacterium: 3-(1-hexenyl)-5-hydroxy-5-methyl-2-(5H)-furanone and 3-(1-hexenyl)-5-hydroxymethyl-2-(5H)-furanone. This volatile antifungal furanone has structural similarity to other antifungal furanones produced by actinomycetes (Streptomyces spp.), fungi (Trichoderma harzianum), and higher plants (Pulsatilla and Ranuculus spp.). This is the first report of 3-(1-hexenyl)-5-methyl-2-(5H)-furanone produced by a bacterium.
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... Likewise, different compounds with antimicrobial activity were detected, such as furanones, dimethyl disulfide, 2,6,6-trimethyl-1-Cyclohexene-1-acetaldehyde, and muurola derivatives [53,57,58]. It is worth highlighting the production of caryophyllenyl alcohol, identified in several samples in both media and associated with several applications in cosmetics and derivatives in the drug industry (hypolipidemic, anti-inflammatory properties [59][60][61][62]. ...
... Likewise, different compounds with antimicrobial activity were detected, such as furanones, dimethyl disulfide, 2,6,6-trimethyl-1-Cyclohexene-1-acetaldehyde, and muurola derivatives [53,57,58]. It is worth highlighting the production of caryophyllenyl alcohol, identified in several samples in both media and associated with several applications in cosmetics and derivatives in the drug industry (hypolipidemic, anti-inflammatory properties [59][60][61][62]. Those compounds that were exclusively produced via SFM medium confrontation demanded attention: no activity has been described for 1,2,4,5-Tetrazin-3-amine or bis(1,1,3,3-tetramethylbutyl) disulfide in the literature. ...
... The same applies to liguloxide, which is also part of plant essential oils [83]. (1S,4S,4aS)-1-Isopropyl-4,7-dimethyl-1,2,3,4,4a,5hexahydronaphthalene is a stereoisomer of cis-muurola-3,5-diene, which has already been described [59]. Previously, we revealed the antifungal properties of disulfite and furanone derivatives. ...
The study of volatile organic compounds (VOCs) has expanded because of the growing need to search for new bioactive compounds that could be used as therapeutic alternatives. These small molecules serve as signals to establish interactions with other nearby organisms in the environment. In this work, we evaluated the antifungal effect of VOCs produced by different Streptomyces spp. This study was performed using VOC chamber devices that allow for the free exchange of VOCs without physical contact between microorganisms or the diffusible compounds they produce. Antifungal activity was tested against Escovopsis weberi, a fungal pathogen that affects ant nest stability, and the results showed that Streptomyces spp. CS014, CS057, CS131, CS147, CS159, CS207, and CS227 inhibit or reduce the fungal growth with their emitted VOCs. A GS-MS analysis of volatiles produced and captured by activated charcoal suggested that these Streptomyces strains synthesize several antifungal VOCs, many of them produced because of the presence of E. weberi, with the accumulation of various VOCs determining the growth inhibition effect.
... These compounds inhibit pathogens' growth and metabolic activity by sequestering iron (Haggag et al., 2007). Moreover, volatile ammonia is also reported as an inhibitory mechanism to control diseases caused by R. solani and other pathogens (Paulitz et al., 2000). ...
... μM (Hong & Cho 2013). Compounds from the furanone family have various biological activities, such as cytotoxicity and antifungal activity as well as AF activity (Paulitz et al. 2000;Cho et al. 2006). Xu et al. (2010) described other furanone derivatives isolated from the marine bacterium Streptomyces sp. which showed excellent AF activity. ...
This review covers 214 marine natural compounds and 23 of their synthetic analogs, which were discovered and/or synthesized from mid-2009 to August 2014. The antifouling (AF) compounds reported have medium to high bioactivity (with a threshold of EC 50 < 15.0 mg ml −1). Among these compounds, 82 natural compounds were identified as new structures. All the compounds are marine-derived, demonstrating that marine organisms are prolific and promising sources of natural products that may be developed as environmentally friendly antifoulants. However, this mini-review excludes more than 200 compounds that were also reported as AF compounds but with rather weak bioactivity during the same period. Also excluded are terrestrial-derived AF compounds reported during the last five years. A brief discussion on current challenges in AF compound research is also provided to reflect the authors' own views in terms of future research directions.
... There are reports on literature on the potential of their metabolites, both volatile and non-volatile, against phytopathogenic microorganisms including R. solani (Sasirekha and Srividya, 2016;Wang et al., 2021). Phenazines (Shanmugaiah et al., 2010), furanones (Paulitz et al., 2000), pyrroles (Howell, 1979;Cartwright et al., 1995), and cyclic lipopeptides (Hua and Höfte, 2015;Oni et al., 2020) are among the main compounds responsible for the activity related specifically against this fungal pathogen. Regarding to the cyclic lipopeptides, it is interesting to bring up the results reported by Nielsen et al. (2000), who detected and isolated a tensin compound from extracts of a P. fluorescens strain and tried to apply an OSMAC approach to study tensin production and search for other bioactive compounds produced on different culture media. ...
Introduction: Phytopathogenic fungi are a considerable concern for agriculture, as they can threaten the productivity of several crops worldwide. Meanwhile, natural microbial products are acknowledged to play an important role in modern agriculture as they comprehend a safer alternative to synthetic pesticides. Bacterial strains from underexplored environments are a promising source of bioactive metabolites.
Methods: We applied the OSMAC (One Strain, Many Compounds) cultivation approach, in vitro bioassays, and metabolo-genomics analyses to investigate the biochemical potential of Pseudomonas sp. So3.2b, a strain isolated from Antarctica. Crude extracts from OSMAC were analyzed through HPLC-QTOF-MS/MS, molecular networking, and annotation. The antifungal potential of the extracts was confirmed against Rhizoctonia solani strains. Moreover, the whole-genome sequence was studied for biosynthetic gene clusters (BGCs) identification and phylogenetic comparison.
Results and Discussion: Molecular networking revealed that metabolite synthesis has growth media specificity, and it was reflected in bioassays results against R. solani. Bananamides, rhamnolipids, and butenolides-like molecules were annotated from the metabolome, and chemical novelty was also suggested by several unidentified compounds. Additionally, genome mining confirmed a wide variety of BGCs present in this strain, with low to no similarity with known molecules. An NRPS-encoding BGC was identified as responsible for producing the banamides-like molecules, while phylogenetic analysis demonstrated a close relationship with other rhizosphere bacteria. Therefore, by combining -omics approaches and in vitro bioassays, our study demonstrates that Pseudomonas sp. So3.2b has potential application to agriculture as a source of bioactive metabolites.
... The pathogenic stress also influenced the production of furanone and dihydroacaterin by strain SK2. Furanone is known to exhibit biocontrol activity (Paulitz et al. 2000;Guevara-Avendaño et al. 2019, Yang et al. 2021). Our study is the first to report the strain SK2, closely related to Pseudomonas sp. ...
Purpose
Soil management exerts profound impact on the structure and function of the microbiome. Organic practice is believed to positively affect disease suppressiveness compared to conventional systems. While Pseudomonas has been established as a major player in conferring suppressiveness, the impact of farming practices on its diversity at species level has not been conclusively understood. Also, translation of such knowledge into application requires a mechanistic understanding of the mechanism of action of potent biocontrol strains of Pseudomonas.
Methods and results
We compared fields under conventional and organic farming, under long-term (~19 years) management. Profiling of Pseudomonas community structure using rpoD-based amplicon sequencing revealed a higher diversity of known antagonistic Pseudomonas spp. in soils sampled from organic fields compared to conventional field. Cultivation and genome sequencing of selected Pseudomonas isolates from the organic field identified species with multiple secondary metabolite biosynthetic gene clusters and antagonistic activity towards phytopathogens. The selected Pseudomonas isolates showed colonization of wheat root system as confirmed by scanning electron microscopy. In vitro tube assay using wheat also revealed the suppressive activity of potent Pseudomonas isolates against Fusarium oxysporum and Verticillium dahliae. Production of metabolites with antimicrobial activity was verified using untargeted metabolomics (LC/MS).
Conclusions
Overall, the mechanistics involved in the contribution of Pseudomonas spp. to disease suppressiveness in the field under organic farming could be established. This study reports that microbiome from organic field exhibits enhanced diversity of antagonistic Pseudomonas spp. effective against phytopathogens, compared to the conventional practice, and has the potential to promote sustainable agriculture and disease management.
... These compounds inhibit pathogens' growth and metabolic activity by sequestering iron (Haggag et al., 2007). Moreover, volatile ammonia is also reported as an inhibitory mechanism to control diseases caused by R. solani and other pathogens (Paulitz et al., 2000). ...
Sustainable development relies heavily on a food system that is both safe and secure. Several approaches may lead to sustainability and food safety. An increase in the cultivation of legume crops is one of the approaches for enhancing agricultural viability and ensuring adequate food supply. Legumes may increase daily intake of fiber, folate, and protein as substitutes for meat and dairy. They are also crucial in various intercropping systems worldwide. However, legume production has been hampered by Rhizoctonia solani due to its destructive lifestyle. R. solani causes blights, damping off, and rotting diseases in legume crops. Our knowledge of the global distribution of R. solani associated with legume crops (alfalfa, soybean, chickpea, pea, lentil, common bean, and peanut), detection, diagnosis, and management of legume crops diseases caused by R. solani is limited. Traditional approaches rely on the incubation of R. solani, visual examination of symptoms on host legume crops, and microscopy identification. However, these approaches are time-consuming, require technical expertise, fail to detect a minimal amount of inoculum, and are unreliable. Biochemical and molecular-based approaches have been used with great success recently because of their excellent sensitivity and specificity. Along with conventional PCR, nested PCR, multiplex PCR, real-time PCR, magnetic-capture hybridization PCR, and loop-mediated isothermal amplification have been widely used to detect and diagnose R. solani. In the future, Next-generation sequencing will likely be used to a greater extent to detect R. solani. This review outlines global distribution, survival, infection and disease cycle, traditional, biochemical, molecular, and next-generation sequencing detection and diagnostic approaches, and an overview of the resistant resources and other management strategies to cope with R. solani.
... All the isolates produced ammonia (NH 3 ) which was in close agreement with (Joseph et al. 2007;Geetha et al. 2014) who reported the production of ammonia by all rhizobacteria isolated from chickpea and green gram. Ammonia is important to control soil borne pathogens (Paulitz et al. 2000), promotes plant growth through making nitrogen available to the plant (Kandjimi et al. 2015), promotes plant growth by suppressing fungal pathogens in the rhizosphere (Bhattacharyya and Jha 2012), and enhance plant growth as a result of their ability to fix nitrogen (N 2 ) to ammonia (NH 3 ) making more NH 3 available for plant growth (Hayat et al. 2010). This property can be of a particular importance to grass pea, which has high protein containing seeds (Yang and Zhang 2005) and grows in poor and nitrogen-deficient marginal lands (Anteneh et al. 2011). ...
Aim
The main aim of this work was to examine the plant growth promoting, biocontrol activities and stress competency of grass pea rhizobacterial strains from Ethiopia.
Methods and Results
Serial dilutions were carried out to isolate rhizobacterial strains from the rhizosphere soil samples. The isolates were characterized for their plant growth promoting, biocontrolling and stress tolerance potential. The isolates that showed better performance in the tested parameters were identified by 16S rRNA gene sequencing. Among the isolates tested on Pikovskaya agar medium, 22 isolates that showed solubilization index of >2·41 cm were selected for further screening tests. Isolate AAUGPR-53 identified as Enterococcus species, Enterococcus casseliflavus strain showed the highest phosphate solubilization index and indole-3-acetic acid production efficiency of 4·81 ± 0·02 (μg ml−1) and 56·55 ± 0·45 (μg ml−1), respectively. Sixteen (72·7%) of the isolates showed in vitro antifungal inhibition against Fusarium oxysporum f. sp. lentis with isolates AAUGPR-92 and AAUGPR-91 identified as Enterococcus species, E. casseliflavus strain and Enterococcus gallinarum strain exhibiting the highest inhibition of 83 and 78%, respectively. Likewise, 68·2%, 91·30%, 45·5%, 77·3% and 100% of the isolates produced chitinase, protease, cellulase, HCN and NH3, respectively. Most of the isolates showed good tolerance to the tested stress factors. The 16S rRNA partial sequencing of the rhizobacterial isolates proved their taxonomic position in the existing bacterial isolates.
... Rajpoot and Panwar (2013) and Singh et al., (2013) reported that 66.7 % of ammonia producing rhizobial isolates from Vagina radiate and Pigeon pea. The production of volatile ammonia by these rhizobial isolates is an implication to control soil borne pathogens (Paulitz et al., 2000). It can also be said that inoculation with such NH 3 producing rhizobia may enhance the plant growth as a result of their ability to fix nitrogen (N 2 ) to ammonia (NH 3 ) making it an available nutrient for plant growth (Hayat et al., 2010). ...
BIOLOGY Declaration This is to certify that the Dissertation prepared by Mussa Adal Mohammed, entitled "Diversity, symbiotic and plant growth promoting properties of rhizobia and rhizobacteria of grass pea (Lathyrus sativus L.) from central Ethiopia: implication to the selection and use of microbial inoculants in low input agriculture in Ethiopia" and submitted in fulfillment of the Requirements for the Degree of Doctor of Philosophy (Biology: Applied Microbiology) complies with the regulations of the University and meets the accepted standards with respect to originality and quality. Name: Mussa Adal Mohammed Signature: _________________________________ Date: ____________________________________ Supervisor: Fassil Assefa (Assoc. professor) Signature______________________________ Date__________________________________
General plant diseases as well as soil‐borne pathogens severely reduce
agricultural yield. The rhizosphere (the region of the soil that includes and
surrounds the roots) is an important niche for microbial diversity in particular
phytobeneficial bacteria including plant growth‐promoting rhizobacteria
(PGPR) which have been used for a very long time to combat plant diseases.
Pathogen control and crop productivity can both be improved through the use
of PGPR several mechanisms, including iron‐based nutrition, antibiotics,
volatile substances, enzymes, biofilm, allelochemicals, and so on. Their modes
of action and molecular mechanisms have improved our comprehension of
how they are used to control crop disease. Therefore, there is a lot of literal
information available regarding PGPR, but this review stands out since it starts
with the fundamentals: the concept of the rhizosphere and the colonization
process of the latter, particularly because it covers the most mechanisms. A
broad figure is used to present the study's findings. The advantages of using
PGPR as bioinoculants in sustainable agriculture are also mentioned.
Plant growth promoting rhizobacteria (PGPR) residing in soil rhizosphere provide enormous beneficial effects to a plant host producing diverse secondary metabolites and enzymes useful for plant growth and protection. Siderophores, antibiotics, volatile compounds and hydrolytic enzymes are the major molecules secreted by the PGPRs, which have substantial antifungal properties and can provide plant protection. These compounds are responsible for the lysis and hyperparasitism of antagonists against deleterious fungal pathogens. Siderophore-producing PGPRs function by depriving the pathogen of iron nutrition. Antibiotics have been reported to be involved in the suppression of different fungal pathogens by inducing fungistasis, inhibition of spore germination, lysis of fungal mycelia. The PGPRs also secrete a wide range of low molecular weight volatile organic compounds (VOCs) that inhibit mycelial growth, sporulation, germination of phytophathogenic fungi, etc. Hydrolytic enzymes, mostly chitinase, protease and cellulose, lyse the cell wall of fungi. Therefore, plant growth-promoting rhizobacteria can be considered as an effective, eco-friendly, and sustainable replacement to the chemical fungicides. There are many PGPRs that perform very well in controlled conditions but not in field conditions, and hence the commercializing of hese products is not easy. Development of formulations with increased shelf life, a broad spectrum of action and consistent performance under field conditions can pave the way for commercializing the PGPRs at a faster rate. Journal of Bangladesh Academy of Sciences, Vol. 44, No. 2, 69-84, 2020
The resurgence of interest in the use of introduced microorganisms for biological control of plant pathogens during the past 10 years has been driven in part by trends in agriculture toward greater sustainability and increased public concern for hazards associated with the use of synthetic pesticides. Rapidly evolving technologies from molecular biology and genetics have provided new insights into the underlying mechanisms by which biocontrol agents function and have allowed evaluation of the behavior of microbial inoculants in natural environments to a degree not previously possible. The results from these advances bear directly on two fundamental sources of inconsistency in the performance of microorganisms introduced for biological control that until now have retarded their commercial development and widespread use, namely, inadequate colonization of the target site and variability in the expression or level of activity of the mechanism(s) responsible for pathogen suppression.
PA-147 (I) was isolated from the fermentation liquors of an unidentified Streptomyces strain. The antibiotic has the empirical formula C6H6O2 and was characterized as its barium salt (C6H5O3)Ba·H2O. The structure of the antibiotic was established as 3-carboxy-2,4-pentadienal lactol (Ib) and was proved by synthesis of tetrahydro-PA-147-dicarboxylic acid (IV) which is identical with ethylsuccinic acid.
Pseudomonas fluorescens strain CHA0 suppresses various plant diseases caused by soilborne fungi and procedures several antibiotic metabolites, two of which have been identified as pyoluteorin (Plt) and 2,4-diacetyl-phloroglucinol (Phl). A cosmid (pME3090) carrying a 22(kb insert of strain CHA0 DNA enhanced, in a CHA0 background, the production of Plt in vitro (...)
Labeling experiments using [1,2-13C2]acetate and [U-13C6]glucose on menaquinone and naphterpin produced by Streptomyces aeriouvifer proved simultaneous operation of the mevalonate and non-mevalonate pathways for the formation of isopentenyl diphosphate in this organism.