The bZIP transcription factor SlAREB1 regulates anthocyanin biosynthesis in response to low temperature in tomato.

Low temperature and abscisic acid (ABA) are the two main factors that induce anthocyanin synthesis. However, their potential relationships in the regulating anthocyanin biosynthesis in tomato seedlings is still unclear. Our study revealed the involvement of the transcription factor SlAREB1 in the low-temperature response of tomato seedlings via the ABA-dependent pathway, which required a certain temperature range. Overexpression of SlAREB1 enhanced the anthocyanin-related genes expression and the anthocyanins accumulation, especially at low-temperature conditions, whereas silencing SlAREB1 remarkably reduced gene expression and anthocyanin accumulation. There is a direct interaction between SlAREB1 and the promoters of SlDFR and SlF3'5'H, which are structural genes that impact the anthocyanin biosynthesis. SlAREB1 can regulate anthocyanins through controlling SlDFR and SlF3'5'H expression. Accordingly, SlAREB1 takes charge of regulating anthocyanin biosynthesis in tomato seedlings via the ABA-dependent pathway at low temperatures.