Whole-Genome analysis of <i>Bacillus subtilis</i> NRCB002 and characterization of its metabolite acetoin as a plant growth stimulant

Plant growth-promoting rhizobacteria (PGPR) are instrumental in enhancing crop productivity and resilience to stress. In this study, we characterized <i>Bacillus subtilis</i> subsp. <i>subtilis</i> NRCB002, a PGPR strain isolated from the rice rhizosphere, using genomic and functional analyses. Whole-genome sequencing revealed a circular chromosome of 4,211,270 base pairs with a GC content of 43.51%, encoding genes associated with environmental adaptation, such as antimicrobial resistance, and PGPR-related traits, including the biosynthesis of indole-3-acetic acid. The annotation of key metabolic pathways for acetoin production aligns with its observed role in promoting plant growth. Pot experiments demonstrated that optimal acetoin concentrations significantly enhanced the development of soybean seedlings. These findings elucidate the genetic basis of NRCB002's beneficial traits and underscore its potential for agricultural application.