UV-C radiation promoted flavonoid synthesis during early healing in potato tuber wounds with the possible involvement of ABA and related transcription factor regulation

UV-C radiation has been widely proven to promote flavonoid synthesis in fruit and vegetables as an environmentally friendly treatment. However, it is unknown whether UV-C promotes flavonoid synthesis in potato tuber wounds during early healing and its possible regulatory mechanism. In this study, UV-C radiation increased the gene expression and activities of zeaxanthin epoxidase (ZEP) and 9-cis-epoxycarotenoid dioxygenase (NCED), and increased ABA levels. Meanwhile, UV-C upregulated the expression levels of StPYR1, StPYR2, StPYR3, StPP2C, SnRK2.1 and StABF, and promoted ABA signaling in tuber wounds. In addition, UV-C upregulated the expression levels of related transcription factors, including StMYB12, StMYB308, StbHLH93 and StbHLH143. Furthermore, UV-C regulated the gene expression and activities of chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H) and flavonol synthase (FLS), and promoted the accumulation and synthesis of flavonoids in tuber wounds. It is suggested that ABA and related transcription factors, including StMYB12, StMYB308, StbHLH93 and StbHLH143, may be involved in the regulation of UV-C radiation-driven flavonoid synthesis in potato tuber wounds during early healing.