StRAP2.3, an ERF‐VII transcription factor, directly activates StInvInh2 to enhance cold-induced sweetening resistance in potato

Abstract

AbstractPotato invertase inhibitor (StInvInh2) positively regulates cold-induced sweetening (CIS) resistance by inhibiting the activity of vacuolar invertase. The distinct expression patterns ofStInvInh2have been thoroughly characterized in different potato genotypes, but the related CIS ability has not been characterized. The understanding of the regulatory mechanisms that controlStInvInh2transcription is unclear. In this study, we identified an ERF‐VII transcription factor,StRAP2.3, that directly regulatesStInvInh2to positively modulate CIS resistance. Acting as a nuclear-localized transcriptional activator, StRAP2.3 directly binds the ACCGAC cis-element in the promoter region ofStInvInh2, enabling promoter activity. Overexpression ofStRAP2.3in CIS-sensitive potato tubers inducedStInvInh2mRNA abundance and increased CIS resistance. In contrast, silencingStRAP2.3in CIS-resistant potato tubers repressed the expression ofStInvInh2and decreased CIS resistance. We conclude that cold-responsiveStInvInh2is due to the binding of StRAP2.3 to the ACCGAC cis-element in the promoter region ofStInvInh2. Overall, these findings indicate that StRAP2.3 directly regulatesStInvInh2to positively modulate CIS resistance, which may provide a strategy to improve the processing quality of potatoes.