Antifungal Activity of Endophytic K1 Against .

Gray mold caused by is detrimental to plants and fruits. Endophytes have been shown to modify plant disease severity in functional assays. We conducted this study to investigate the endophytic strain K1 with excellently antagonistic from the wild grape endosphere. We identified a wild grape endophytic strain K1 with high antifungal activity against both and . Combining the phylogenetic results based on 16S rDNA and genome sequencing, K1 was assigned as . The results displayed that K1 and its volatile substances could significantly inhibit the mycelia growth of . Grape fruit inoculated with K1 showed lower gray mold during treatment. The higher levels of defense-related enzymes, including peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase, were induced in grapes after inoculation. Scanning electron microscopy (SEM) suggested that K1 inhibited mycelial growth bacterial colonization and antibiosis in grapes. The gas chromatography-mass spectrometry analysis identified 33 volatiles in which dibutyl phthalate was the major compound accounting for 74.28%. Dibutyl phthalate demonstrated strong activity in suppressing the mycelia growth of . Genome bioinformatics analysis revealed that the K1 chromosome harbored many known biosynthesis gene clusters encoding subtilosin, bacillaene, bacillibactin, bacilysin, and fengycin. This study provides a potential biological agent to control diseases of post-harvest grape fruit and improves our understanding of the possible biocontrol mechanisms of the strain.