Gibberellins Negatively Regulate Low Temperature-Induced Anthocyanin Accumulation In A Hy5/Hyh-Dependent Manner

Low temperature could significantly induce anthocyanin accumulation in the presence of light. Recently, two bZIP transcription factors LONG HYPOCOTYL 5 (HY5) and HOMOLOG OF HY5 (HYH) were identified to play an important role in the process of low temperature-induced anthocyanin accumulation. However, the mechanism by which HY5/ HYH regulates anthocyanin accumulation under low temperature still remains unclear. Here, we found that the gibberellins (GAs) could decrease but PAC (endogenous GAs biosynthesis inhibitor) increases the low temperatureinduced anthocyanin accumulation, implying that GAs signaling may involve in this process. Furthermore, the transcript level of GA2ox1, encoding a major member of bioactive GAs-deactivating enzymes, was significantly upregulated by low temperature in a HY5/HYH-dependent manner. Moreover, hy5 hyh mutant was insensitive to PAC in enhancing anthocyanin accumulation under low temperature. From these data we propose that, together with HY5/HYH, GA signaling may play an important role during low temperature-induced anthocyanin accumulation.