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.
Project description:To study microbial interaction effect on transcriptomic profile of B. velezensis 83, a comparative gene expression profiling analysis was performed.
Project description:Plant growth-promoting rhizobacteria (PGPR) have been reported to influence plant growth, yield, and nutrient uptake by an array of mechanisms. Uncovering the behavioral dynamics of PGPR is one of the most important issues necessary for understanding their functional performances. In this study, strain NJAU-Z9 which was found to possess complex functions and efficient rhizospheric colonization ability was selected from plenty of bacterial strains isolated randomly from the pepper rhizosphere soil and identified as Bacillus velezensis. Repeated seedling nursing tests performed absolute growth-promoting advantage for the novel isolated strain. After that, primers for the quantitative detection were designed based on its whole genome sequence (WGS), and a real-time PCR method was utilized to explore strategies for monitoring the strain in natural soil and in the pepper rhizosphere. Results showed based on the whole genome, two primers were identified as NJAU-Z9-specific quantitative PCR primers. Two seasonal pot experiments demonstrated that strain NJAU-Z9 effectively colonized the rhizosphere measured by the novel abundance detecting strategy, improved plant growth, and showed a positive correlation between bacterial number and biomass. This study offers a strategy based on a real-time PCR method for directly monitoring B. velezensis strain NJAU-Z9 in the soil and the rhizosphere and provides a reference for the quantitative study of other PGPR strains based on WGSs.
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.
