Abstract: Bacillus velezensis Bam-6 had strong inhibitory activity against bacterial citrus canker and other plant pathogens and had ability to eliminate peach aphids, in order to explore Bam-6 special functional genes and gene clusters, and further study its antibacterial and insecticidal mechanism, the whole genome sequencing was performed using the BGISEQ II and PacBio III platforms, and the sequencing data were employed for genome assembly, gene prediction and functional annotation, collinearity analysis, secondary metabolite synthesis gene cluster prediction, and comparative genome analysis. The whole genome of Bam-6 is 3,928,774 bp in length with a GC content of 46.53%, potentially producing 3,861 ORFs, and the genome has a total of 86 tRNA, 28 rRNA, 0 sRNA, 122 tandem repeats, and 2 satellite DNA. Up to 3840, 2156, 3485, 3319, or 2721 potential genes were annotated in the NR, Swiss-Prot, eggNOG, Gene Ontology, or Kyoto Encyclopedia of Genes and Genomes databases, respectively. Besides, 12 secondary metabolite gene clusters were predicted, including 3 gene clusters with unknown functions, 8 antibiotic synthesis gene clusters with high similarity (surfactin, macroactin H, fengycin, bacillaene, difficidin, bacillibactin, bacilysin, and mersacidin), and 1 antibiotic gene cluster with only 7% similarity (butirosin A/B). Compared with other B. velezensis strains, Bam-6 has many ORFs with low similarity, 22 specific gene clusters, and 2 unique single-copy genes that encode bacteriocin-like WGxF protein and lactococcin 972, respectively. The present study provides basic data for analyzing the internal factors of the antibacterial and aphid-killing mechanisms of the Bam-6 strain at the genomic level and presents reference information for further understanding the secondary metabolic synthesis pathway of B. velezensis. These results are of great significance for further research on the Bam-6 strain.

Key words: Bacillus velezensis, genome, gene annotation, secondary metabolism