PpMYB308 is involved in Pichia guilliermondii-induced disease resistance against Rhizopus rot by activating the phenylpropanoid pathway in peach fruit

Pichia guilliermondii has been shown to control fungal decay in various harvested fruits by inducing disease resistance, but the transcriptional regulatory mechanism remains unclear. In our study, P. guilliermondii treat-ment induced resistance against soft rot caused by Rhizopus stolonifer in peach fruit, as shown by the reduced disease incidence and severity, increased enzyme activities and gene expression of phenylalanine ammonia-lyase (PAL) and 4-coumarate-CoA ligase (4CL), and promoted the accumulation of total phenolics, total flavonoids and the main individual phenolic compounds (neochlorogenic acid, chlorogenic acid, gallic acid, and rutin). In addition, P. guilliermondii induced the expression of PpMYB308, which was identified as a nucleus-localized transcriptional activator of PpPAL1 and Pp4CL5 by binding to the MREs (MYB recognition elements). Moreover, the transient overexpression of PpMYB308 in peach fruit enhanced the expression of PpPAL1 and Pp4CL5 and reduced disease incidence and severity. Therefore, the results indicate that PpMYB308 is involved in P. guilliermondii-induced disease resistance against R. stolonifer by activating the phenylpropanoid pathway.