Genome sequence of Bacillus subtilis BSS.2162 isolated from Caatinga biome reveals potential for plant growth promotion under drought stress

We assessed the potential of Bacillus subtilis BSS.2162 to promote plant growth under water deficit conditions through genomic analyses and a greenhouse assay. The genome sequence has a total size of 4.1 Mb, with a GC content of 43.67%, harboring 4,077 coding sequences (CDSs) and 80 RNA genes. The strain exhibited a genetic framework specialized for tolerance to abiotic stresses, encompassing genes associated with antioxidant responses, sporulation, exopolysaccharide (EPS) production, osmoregulation, and homeostasis mechanisms. These featuress reflect the strain's adaptation to the Caatinga biome, an environment characterized by high temperatures and low rainfall, which exerts selective pressure on microbial communities, favoring microorganisms with specialized genetic and biochemical traits. Additionally, we identified CDSs associated with nutrient acquisition and metabolism, including phosphorus and potassium solubilization, nitrate assimilation, production of siderophores, and sulfur metabolism; tryptophan biosynthesis; and hydrolytic enzymes. These traits indicate a strong potential for plant growth promoting. Under greenhouse conditions, maize plants inoculated with BSS.2162 and exposed to complete water restriction showed a significant increase (p < 0.05) in all parameters evaluated, showing improvements ranging from 48% to 306% when compared to the control. Genomic analysis, combined with the greenhouse experiment, highlights BSS.2162 as a novel strain with potential to mitigate the effects of water deficit, highlighting the need for complementary approaches to validate its suitability for the development of a bioinoculant for cultivation in arid and semi-arid regions.