hypovirulent strain △ induced defense.

Background: Gray mold, caused by , is one of the major fungal diseases in agriculture. Biological methods are preferred over chemical fungicides to control gray mold since they are less toxic to the environment and could induce the resistance to pathogens in plants. In this work, we try to understand if ginseng defense to could be induced by fungal hypovirulent strain △. encodes Zn(II)Cys transcription factor which regulates fungal pathogenicity and we recently reported △ mutants reduced fungal virulence.

Methods: We performed transcriptomic analysis of the host to investigate the induced defense response of ginseng treated by △. The metabolites in ginseng flavonoids pathway were determined by UPLC-ESI-MS/MS and the antifungal activates were then performed.

Results: We found that △ enhanced the ginseng defense response when applied to healthy ginseng leaves and further changed the metabolism of flavonoids. Compared with untreated plants, the application of △ on ginseng leaves significantly increased the accumulation of p-coumaric acid and myricetin, which could inhibit the fungal growth.

Conclusion: △ could effectively induce the medicinal plant defense and is referred to as the biological control agent in ginseng disease management.