Project description:Lipopeptide biosurfactant producing Bacillus strains have many useful applications in biotechnology and agriculture, based on their emulsifying, surface activity and antimicrobial properties. In the current study, lipopeptide production kinetics, and biocontrol potentials of two new B. velezensis strains, ES1-02 and EFSO2-04 were analyzed and compared with those of commercial strains QST713 and FZB42. ES1-02 and EFSO2-04 showed higher specific growth rates than FZB42, but lower growth rates than QST713. All strains produced surfactin lipopetides, while fengycin production was not observed in ES1-02 and EFSO2-04. Production of fengycin A, B, X and Y were however confirmed in strains QST713 and FZB42. Significant differences were observed in the production of lipopeptides of the iturin family. While ES1-02 and EFSO2-04 produced bacillomycin L, QST713 produced iturin A, and FZB42 produced bacillomycin D. This was in line with the PCR analysis of corresponding genes encoding the identified lipopeptides. Highest surfactin titer of 97.4 mg/L was observed in ES1-02, while QST713 produced highest amount of iturin/bacillomycin (8.5 mg/L). Surfactin isoforms C12 to C17, and iturin/bacillomycin isoforms C11 to C17 were identified by mass spectrometry. ES1-02 and EFSO2-04 showed biocontrol potentials comparable with that of QST713 against Diaporthe spp., while FZB42 showed superior antifungal potentials. Up to 41%, 43%, 47 % and 68.9 % inhibition of D. caulivora were achieved by ES1-02, EFSO2-04, QST713 and FZB42 respectively. Upon exposure to B. velezensis strains, morphological changes to Diaporthe hyphae in form of swellings, distortion, and complete disruption occurred. Interaction of D. longicolla DPC_HOH20 with ES1-02 and EFSO2-04 induced 10-fold and 5-fold increase in surfactin synthesis, respectively. Antagonist interaction with D. longicolla induced significant changes in the proteome of ES1-02 including an increased abundance of several proteins associated with biosynthesis of antimicrobial compounds and fatty acids, while proteins associated with phosphate uptake were decreased in abundance.
Project description:Lecanicillium fungicola, the causative agent of dry bubble disease on Agaricus bisporus results in significant crop losses for mushroom growers worldwide. Dry bubble disease is treated through strict hygiene control methods and the application of chemical fungicides but an increase in fungicide resistant L. fungicola strains has resulted in a need to develop alternative biocontrol treatment methods. The aim of the work presented here was to evaluate the response of L. fungicola to a Bacillus velezensis isolate to assess its potential as a novel biocontrol agent. The bacterial species in Serenade, a commercially available biocontrol treatment was also included in this analysis. Exposure of 48 hr L. fungicola cultures to 25% v/v 96h B. velezensis culture filtrate resulted in a 45% reduction in biomass (P < 0.0002) and a disruption in hyphal structure and morphology. Characterisation of the proteomic response of L. fungicola following exposure to B. velezensis culture filtrate revealed an increase in the abundance of a variety of proteins associated with stress response (Norsolorinic acid reductase (+8 fold), isocitrate lyase (+7 fold) and MMS19 nucleotide excision repair protein (+4 fold). There was also a decrease in the abundance of proteins associated with transcription (40S ribosomal protein S30 (-33 fold), 60S ribosomal protein L5 (-45 foldThe results presented here indicate that B. velezensis culture filtrate is capable of inhibiting the growth of L. fungicola and inducing a stress response, thus indicating its potential to control this important pathogen of mushrooms.
Project description:Cladobotryum mycophilum, the causative agent of cobweb disease on Agaricus bisporus results in significant crop losses for mushroom growers worldwide. Cobweb disease is treated through strict hygiene control methods and the application of chemical fungicides but an increase in fungicide resistant Cladobotryum strains has resulted in a need to develop alternative biocontrol treatment methods. The aim of the work presented here was to evaluate the response of C. mycophilum to a Bacillus velezensis isolate to assess its potential as a novel biocontrol agent. Exposure of 48 hr C. mycophilum cultures to 25% v/v 96h B. velezensis culture filtrate resulted in a 57% reduction in biomass (P < 0.0002), a disruption in hyphal structure and morphology, and the appearance of aurofusarin in culture medium. Proteomic analysis of B. velezensis culture filtrate revealed the presence of peptidase 8 (subtilisin), peptide deformylase and probable cytosol aminopeptidase which are known to induce cell disruption. Characterisation of the proteomic response of C. mycophilum following exposure to B. velezensis culture filtrate revealed an increase in the abundance of a variety of proteins associated with stress response (ISWI chromatin-remodelling complex ATPase ISW2 (+24 fold), carboxypeptidase Y precursor (+3 fold) and calmodulin (+2 fold). There was also a decrease in the abundance of proteins associated with transcription (40S ribosomal protein S30 (-26 fold), 40S ribosomal protein S21 (-3 fold) and carbohydrate metabolism, (L-xylulose reductase (-10 fold). The results presented here indicate that B. velezensis culture filtrate is capable of inhibiting the growth of C. mycophilum and inducing a stress response, thus indicating its potential to control this important pathogen of mushrooms.
Project description:The present study aims to evaluate the response of the three Mediterranean local grapevines ‘Garnacha Blanca’, ‘Garnacha Tinta’, and ‘Macabeo’ to treatments with biocontrol products (BPs), a botanical extract (Akivi, Dittrichia viscosa extract) and a beneficial microorganism (Bacillus UdG, Bacillus velezensis). A combination of transcriptomics and metabolomics approaches were chosen in order to study grapevine gene expression and to identify gene marker candidates, as well as, to determine grapevine metabolites differentially concentrated in response to BPs treatments. Grapevine plants were cultivated in greenhouse controlled conditions and submitted to the treatments, and thereafter, leaves were sampled 24h after treatment to conduct gene expression study by RNA-sequencing for ‘Garnacha Blanca’ leaves extract and by RT-qPCR for the three cultivars. Differentially expressed genes (DEGs) were investigated for both treatments and highly influenced DEGs were selected to be tested in the three cultivars as treatment gene markers. In addition, extraction of leaf components was performed to quantify metabolites such as phytohormones, organic acids, and phenols. Considering all the upregulated and downregulated genes and enhanced metabolites concentrations, the treatments had an effect on jasmonic acid, ethylene, and phenylpropanoids defense pathways. In addition, several DEG markers were identified presenting a stable overexpression after the treatments in the three grapevine cultivars. These gene markers could be used to monitor the activity of the products in field treatments in future research. Further research will be necessary to confirm these first results under field conditions.
Project description:Bacillus velezensis strain GH1-13 isolated from a rice paddy soil in Korea has been reported to promote plant growth and inhibit some pathogens. It contains a plasmid pBV71, thought to be of benefit to the strain, but there is no information on its effect. In order to elicit the plasmid effect on gene expression, mRNA and protein levels were analyzed at various stages of bacterial growth. Comparative gene expression profiles between the plasmid-containing and plasmid-free cells revealed that strain GH1-13 activated a transient stress response in the exponential phase. It showed early activation of expression of sigma W operon, liaIHGFSR operon, and transcription regulators for transition state, associated with carbon catabolite repression and secondary metabolite biosynthesis of acetoin, bacillaene, and macrolactin.