Evaluation and Genome Analysis of YB-04 as a Potential Biocontrol Agent Against Wilt and Growth Promotion Agent of Cucumber.

Cucumber wilt caused by f.sp. () 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 It displayed strong antagonistic activity against f.sp. in dual culture and exhibited significant biocontrol of cucumber wilt with a higher control effect than those of previously reported strains and displayed pronounced growth promotion of cucumber seedlings. 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 YB-04 or increased cucumber defense-related enzyme activities for PPO, SOD, CAT, PAL, and LOX. However, the greatest increase was with the combination of YB-04 and . Sequencing the genome of YB-04 showed that it had genes for the biosynthesis of various secondary metabolites, carbohydrate-active enzymes, and assimilation of nitrogen, phosphorous, and potassium. YB-04 appears to be a promising biological control agent against the wilt of cucumber and promotes cucumber growth by genomic, physiological, and phenotypic analysis.