Classification and identification of Bacillus sp. SK007 with biocontrol activity

Abstract:

[Background] Discovery and utilization of microorganisms with biocontrol activity is important to keep crop health and yield in agricultural production. [Objective] Our study aimed to clarify the taxonomic status of Bacillus sp. SK007 isolated from soil, and to validate its antagonistic effect on multiple plant pathogens and, therefore uncover its potential biocontrol functions. [Methods] We first used 16S rRNA gene and whole-genome sequencing analysis to determine the taxonomic status of strain SK007. Plate isolate-antagonistic experiments were applied to explore the antagonistic effect of strain SK007 on Botrytis cinerea, Alternaria brassicicola, Alternaria alternata, Fusarium graminearum and Fusarium solani. AntiSMASH was used to predict antibiotic genes of strain SK007. [Results] Based on the analysis of 16S rRNA gene and whole-genome sequencing, average nucleotide identity and digital DNA-DNA hybridization, the results demonstrated that strain SK007 belonged to Bacillus velezensis, and possessed the genes in producing the lipopeptide antibiotics and polyketone antibiotics. In addition, SK007, with a large number and high abundance of antibiotic gene clusters in genome, exhibited strong resistance to a variety of plant pathogenic fungi. [Conclusion] Bacillus velezensis SK007 has excellent traits in plant disease resistance, and thus has potential roles in facilitating plant resistance to disease and promoting crop yield.