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.
2021-05-17 | PXD008573 | Pride
Project description:Bacillus velezensis SQR9 promotes plant growth through colonization and rhizosphere-phyllosphere bacteria manipulation
Project description:Bacillus velezensis strain GH1-13 with a native conjugative plasmid (pBV71) is thought to be beneficial to the bacterium, although no information on its effects exists. Here we show that strain GH1-13 frequently lost the plasmid during normal growth conditions in a rich medium and changed the morphology and sensitivity to selenite and tellurite. Compared to the plasmid-cured cells, the wild-type and complemented cells exhibited multicellular behavior with the expression of conjugative type IV pili and regulatory Rap homologous genes that regulate the interconnection between conjugation and biofilm formation. Further omics-based analyses of morphogenesis, biofilm formation, and antibiotic synthesis suggest that the conjugative plasmid activates envelope stress responses in association with increased biosynthesis of extracellular polysaccharide and antibiotics for protective functions of the host during exponential phase.
Project description:Plants develop mutualistic association with beneficial rhizobacteria. To understand this important phenomenon, early mechanisms for establishing the mutualism are critical. Here we report that active DNA demethylation in plants controls root secretion of myo-inositol, which triggers and further facilitates colonization of the beneficial rhizobacteria Bacillus megaterium strain YC4, thereby allowing for plant growth-promotion. YC4 promotes plant growth but the beneficial effects were lost in the Arabidopsis mutant rdd that is defective in active DNA demethylation. Roots of rdd failed to associate with YC4, meanwhile the level of myo-inositol in root exudates was drastically reduced in rdd. Supplementation of myo-inositol to rdd restored YC4 colonization and plant growth-promotion, while plants with defective myo-inositol monophosphatase also failed in establishing mutualism with YC4. myo-Inositol not only induced chemotaxis of YC4 but also increased YC4 biofilm production, consistent with the transcriptional regulation of YC4 by myo-inositol. In addition, myo-inositol preferentially attracts Bacillus megaterium among the examined bacteria species. Regardless of YC4 inoculation, myo-inositol biosynthesis and catabolism genes are down- and up-regulated, respectively, in rdd compared to wild type plants. The differential expression of myo-inositol homeostasis genes is correlated with local DNA hypermethylation, whereas genetic disruption of the RNA-directed DNA methylation pathway abolished these epigenetic marks and reset the corresponding gene expression patterns, resulting in restored YC4 colonization and plant growth-promotion. Importantly, that active DNA demethylation controls myo-inositol-mediated mutualism between YC4 and plants was also demonstrated in Solanum lycopersicum. Our results uncover an important function of myo-inositol in plant-microbe interactions and its dependence on plant epigenetic regulation.
Project description:Plants develop mutualistic association with beneficial rhizobacteria. To understand this important phenomenon, early mechanisms for establishing the mutualism are critical. Here we report that active DNA demethylation in plants controls root secretion of myo-inositol, which triggers and further facilitates colonization of the beneficial rhizobacteria Bacillus megaterium strain YC4, thereby allowing for plant growth-promotion. YC4 promotes plant growth but the beneficial effects were lost in the Arabidopsis mutant rdd that is defective in active DNA demethylation. Roots of rdd failed to associate with YC4, meanwhile the level of myo-inositol in root exudates was drastically reduced in rdd. Supplementation of myo-inositol to rdd restored YC4 colonization and plant growth-promotion, while plants with defective myo-inositol monophosphatase also failed in establishing mutualism with YC4. myo-Inositol not only induced chemotaxis of YC4 but also increased YC4 biofilm production, consistent with the transcriptional regulation of YC4 by myo-inositol. In addition, myo-inositol preferentially attracts Bacillus megaterium among the examined bacteria species. Regardless of YC4 inoculation, myo-inositol biosynthesis and catabolism genes are down- and up-regulated, respectively, in rdd compared to wild type plants. The differential expression of myo-inositol homeostasis genes is correlated with local DNA hypermethylation, whereas genetic disruption of the RNA-directed DNA methylation pathway abolished these epigenetic marks and reset the corresponding gene expression patterns, resulting in restored YC4 colonization and plant growth-promotion. Importantly, that active DNA demethylation controls myo-inositol-mediated mutualism between YC4 and plants was also demonstrated in Solanum lycopersicum. Our results uncover an important function of myo-inositol in plant-microbe interactions and its dependence on plant epigenetic regulation.
Project description:Plants develop mutualistic association with beneficial rhizobacteria. To understand this important phenomenon, early mechanisms for establishing the mutualism are critical. Here we report that active DNA demethylation in plants controls root secretion of myo-inositol, which triggers and further facilitates colonization of the beneficial rhizobacteria Bacillus megaterium strain YC4, thereby allowing for plant growth-promotion. YC4 promotes plant growth but the beneficial effects were lost in the Arabidopsis mutant rdd that is defective in active DNA demethylation. Roots of rdd failed to associate with YC4, meanwhile the level of myo-inositol in root exudates was drastically reduced in rdd. Supplementation of myo-inositol to rdd restored YC4 colonization and plant growth-promotion, while plants with defective myo-inositol monophosphatase also failed in establishing mutualism with YC4. myo-Inositol not only induced chemotaxis of YC4 but also increased YC4 biofilm production, consistent with the transcriptional regulation of YC4 by myo-inositol. In addition, myo-inositol preferentially attracts Bacillus megaterium among the examined bacteria species. Regardless of YC4 inoculation, myo-inositol biosynthesis and catabolism genes are down- and up-regulated, respectively, in rdd compared to wild type plants. The differential expression of myo-inositol homeostasis genes is correlated with local DNA hypermethylation, whereas genetic disruption of the RNA-directed DNA methylation pathway abolished these epigenetic marks and reset the corresponding gene expression patterns, resulting in restored YC4 colonization and plant growth-promotion. Importantly, that active DNA demethylation controls myo-inositol-mediated mutualism between YC4 and plants was also demonstrated in Solanum lycopersicum. Our results uncover an important function of myo-inositol in plant-microbe interactions and its dependence on plant epigenetic regulation.
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.