PpMYB1 and PpNPR1 interact to enhance the resistance of peach fruit to Rhizopus stolonifer infection

MYB transcription factors play important role in stress-resistance of plants. Nevertheless, the function of MYB TFs in peach Rhizopus rot remains poorly understood. Herein, Pichia guilliermondii treatment activated resistance against Rhizopus stolonifer, as illustrated by reductions in the incidence rate and severity of Rhizopus rot disease, increased enzyme activities and gene expression of chitinase (CHI) and β-1,3-glucanase (GLU), and enhancement of energy production by inducing the activities and expression of H+-ATPase and Ca2+-ATPase, succinate dehydrogenase (SDH), and cytochrome c oxidase (CCO). Moreover, an R1-type MYB, PpMYB1, from peach fruit was induced during R. stolonifer infection and in response to P. guilliermondii treatment. PpMYB1 activated the transcription of PpCHI-EP3 and PpGLU-like genes and the energy metabolism-related gene PpH+-ATPase1 by directly targeting the MBS element. Importantly, PpMYB1 interacted with PpNPR1 to form a heterodimer, which was conducive to enhancing the activation of target gene transcription. Collectively, our findings suggest that PpMYB1 cooperates with PpNPR1 to positively regulate disease resistance by activating the disease defense system and energy metabolism in peaches.