Genome insights into the Bacillus paramycoides RZ3MS14: a multitrait plant growth-promoting rhizobacterium from...

The genus Bacillus features species with remarkable plant growth-promoting traits (PGPTs) and is widely recognized for its biotechnological potential in sustainable agriculture. Among them, Bacillus paramycoides has recently attracted attention for its versatility in green synthesis of biopolymers, metal-based nanoparticles, and inhibition fungal phytopathogens; however, its PGPTs remain poorly underexplored. In this study, an integrated genomic and physiological approach was applied to B. paramycoides RZ3MS14, isolated from the guarana rhizosphere in Amazonian rainforest, to explore and correlate its potential PGPTs through in vitro and in vivo assays. The genome of B. paramycoides RZ3MS14 harbors genes related to N/P/Fe mobilization, bacillibactin synthesis, exopolysaccharides and biofilm formation, plant signaling, stress tolerance, biocontrol, and antibiotic resistance. Functional validation through in vitro assays, confirmed the strain's ability to solubilize phosphate, mineralize phytate, and produce siderophores, auxins, exopolysaccharides, and biofilm. These findings point diverse plant-growth promoting (PGP) traits that contributed to significant improvements in sugarcane growth and root architecture in the greenhouse. Specifically, root dry mass, shoot dry mass, root length, root surface area, and root volume increased by 225.92%, 520.89%, 231.47%, 242.25%, and 252.92%, respectively. Bacillus paramycoides RZ3MS14 exhibited a low antagonistic effect against the phytopathogenic fungi Fusarium verticillioides and Ceratocystis paradoxa. In contrast, microbial volatiles defined synergistic interactions with beneficial fungi Trichoderma afroharzianum and Purpureocillium lilacinum. This is the first study to unveil the PGP attributes of B. paramycoides, underscoring RZ3MS14's potential as a sugarcane bioinput and providing insights into its combined application with other microorganisms.