Abstract
Cold stress adversely affects crop growth and productivity. Resolving the genetic basis of freezing tolerance is important for crop improvement. Wild potato (Solanum commersonii) exhibits excellent freezing tolerance. However, the genetic factors underlying its freezing tolerance remain poorly understood. Here, we identified flavonoid 3'-hydroxylase (F3'H), a key gene in the flavonoid biosynthesis pathway, as highly expressed in S. commersonii compared with cultivated potato (S. tuberosum L.). Loss of ScF3'H function impaired freezing tolerance in S. commersonii, while ScF3'H overexpression in cultivated potato enhanced its freezing tolerance. Metabolic analysis revealed that F3'H generates more downstream products by adding hydroxyl (-OH) groups to the flavonoid ring structures. These flavonoids enhance reactive oxygen species scavenging, thereby contributing to freezing tolerance. Furthermore, the W-box element in the F3'H promoter plays a critical role in cold responses. Cold-induced transcription factor ScWRKY41 directly binds to the ScF3'H promoter region and recruits histone acetyltransferase 1 (ScHAC1), which enhances histone acetylation at the F3'H locus and activates its transcription. Overall, we identified the cold-responsive WRKY41-F3'H module that enhances freezing tolerance by augmenting the antioxidant capacity of flavonoids. This study reveals a valuable natural gene module for breeding enhanced freezing tolerance in potato and other crops.