AUTHOR=Xu Wen , Yang Qian , Yang Fan , Xie Xia , Goodwin Paul H. , Deng Xiaoxu , Tian Baoming , Yang Lirong 

TITLE=Evaluation and Genome Analysis of Bacillus subtilis YB-04 as a Potential Biocontrol Agent Against Fusarium Wilt and Growth Promotion Agent of Cucumber

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.885430

DOI=10.3389/fmicb.2022.885430

ISSN=1664-302X

ABSTRACT=<p>Cucumber wilt caused by <italic>Fusarium oxysporum</italic> f.sp. <italic>cucumerinum</italic> (<italic>Foc</italic>) is a highly destructive disease that leads to reduced yield in cucumbers. In this study, strain YB-04 was isolated from wheat straw and identified as <italic>Bacillus subtilis.</italic> It displayed strong antagonistic activity against <italic>F. oxysporum</italic> f.sp. <italic>cucumerinum</italic> in dual culture and exhibited significant biocontrol of cucumber <italic>Fusarium</italic> wilt with a higher control effect than those of previously reported <italic>Bacillus</italic> strains and displayed pronounced growth promotion of cucumber seedlings. <italic>B. subtilis</italic> YB-04 could secrete extracellular protease, amylase, cellulose, and β-1,3-glucanase and be able to produce siderophores and indole acetic acid. Inoculation with <italic>B. subtilis</italic> YB-04 or <italic>Foc</italic> increased cucumber defense-related enzyme activities for PPO, SOD, CAT, PAL, and LOX. However, the greatest increase was with the combination of <italic>B. subtilis</italic> YB-04 and <italic>Foc</italic>. Sequencing the genome of <italic>B. subtilis</italic> YB-04 showed that it had genes for the biosynthesis of various secondary metabolites, carbohydrate-active enzymes, and assimilation of nitrogen, phosphorous, and potassium. <italic>B. subtilis</italic> YB-04 appears to be a promising biological control agent against the <italic>Fusarium</italic> wilt of cucumber and promotes cucumber growth by genomic, physiological, and phenotypic analysis.</p>