is the target of SlTHM27, positively regulates cold tolerance by mediating anthocyanin biosynthesis in tomato.

Cold stress significantly limits the yield and quality of tomato. Deciphering the key genes related to cold tolerance is important for selecting and breeding superior cold-tolerant varieties. γ-aminobutyric acid (GABA) responds to various types of stress by rapidly accumulating in plant. In this study, glutamic acid decarboxylase (GAD2) was a positive regulator to enhance cold stress tolerance of tomato. Overexpression of decreased the extent of cytoplasmic membrane damage and increased the endogenous GABA content, antioxidant enzyme activities, and reactive oxygen species (ROS) scavenging capacity in response to cold stress, whereas mutant plants showed the opposite trend. In addition, induced anthocyanin biosynthesis in response to cold stress by increasing the content of endogenous GABA. Further study revealed that expression was negatively regulated by the transcription factor SlTHM27. However, the transcript levels of were repressed under cold stress. Antioxidant enzyme activities, transcript levels, GABA and anthocyanin contents were significantly increased in mutant plants. Further, our study demonstrated that SlTHM27 decreases -promoted cold resistance in tomato by repressing transcription. Overall, our results showed that the SlTHM27- model regulates the cold tolerance in tomato by regulating GABA and anthocyanin.