Complete genome sequence of Bacillus velezensis WB, an isolate from the watermelon rhizosphere: genomic insights into its antifungal effects.

OBJECTIVES:Here, we report the complete genome of strain WB, isolated from the rhizosphere of a healthy watermelon from a Fusarium wilt diseased field, which possesses antifungal activity against Fusarium oxysporum f. sp. niveum (Fon) and reduces the incidence of Fusarium wilt in watermelon. METHODS:Genome sequences were determined using the Illumina HiSeq and PacBio platforms. Genome assembly was performed by Unicycler software. Gene clusters responsible for secondary metabolite biosynthesis were predicted using antiSMASH. RESULTS:The size of the genome was 3 896 799 base pairs, and there were 3977 coding DNA sequences (CDSs). The G+C content of the circular genome was 46.65%, and there were 27 rRNAs and 86 tRNAs. Strain WB was finally designated Bacillus velezensis based on phylogenomic analyses. In addition, 13 gene clusters were related to the synthesis of antimicrobial secondary metabolites, including surfactin, fengycin, iturin, bacillibactin, bacilysin, bacillaene, and butirosin. CONCLUSION:The complete genome sequence of strain WB reported here will be a valuable reference for studying the biocontrol mechanisms of Fusarium wilt in watermelon.