Pangenome analysis of Bacillus velezensis exploring the probiotic potential and plant growth promotion traits of strains isolated from fish intestines.

Abstract

New Bacillus velezensis strains with impressive antimicrobial activities are being continuously described. Here we performed genomic comparisons of five B. velezensis strains isolated from Amazonian fish intestines with other 266 genomes from the RefSeq database through a pangenome approach. We aimed to analyze the commonalities and specificities of each strain within this clade to explore their potential as probiotics and for promoting plant growth (PGP). High-quality draft genome sequences were obtained for strains P7 and P11, with genome metrics confirming their identification as B. velezensis. The evaluation of 271 B. velezensis genome sequences revealed an open pangenome composed of 14,918 homologs, while 16% of them represented the core genome. Therefore, the majority of genes belonged to the accessory variable genome, with many strains harboring numerous unique genes, including the Amazonian strain P45. This strain also stood out as carrying the potential to produce many hydrolytic enzymes and PGP traits. Genome mining of all five Amazonian strains annotated secondary metabolites with unknown identifications. The evaluated probiotic genes are mostly conserved in all B. velezensis strains. Moreover, the investigation of the mobilome, resistome, and virulence factors showed that these strains can be considered safe for probiotic and agricultural applications, corroborating our previous studies. This data will be useful to improve our understanding and biotechnological exploration of these strains and other B. velezensis as well.