TaTCP21-A negatively regulates wheat cold tolerance via repressing expression of TaDREB1C.

Cold stress is one of the important harmful factors that seriously affect wheat (Triticum aestivum) yield and quality. TCP transcription factor plays important roles in the process of plant cell proliferation and growth. In this study, we identified 60 TaTCP genes expressed in strong cold resistant winter wheat variety Dongnongdongmai1 (Dn1) under cold stress by previous transcriptome data, of which 13 TaTCPs showed significant differences in expression. The evolution of TaTCPs was analyzed, and the results showed that there were 2 homologous pairs in TaTCPs with AtTCPs and 90 homologous pairs in TaTCPs with OsTCPs. Expression patterns of 20 TaTCPs under cold stress were analyzed by qRT-PCR, and TCP21-A with significant expression differences was screened. We obtained tcp21-A mutant from the EMS mutant library of winter wheat Kenong9204. We observed that the mutation of TaTCP21-A significantly improved its cold resistance. Subsequently, transcriptome analysis revealed that TCP21-A inhibited expression of cold responsive gene TaDREB1C. Finally, subcellular localization and yeast one hybrid were used to verify that TCP21-A can act as a transcription factor to bind to the GGTCCC promoter element. Luciferase reporter gene experiment showed that TCP21-A inhibits the transcriptional activity of the TaDREB1C promoter. In summary, we systematically analyzed the expression patterns of TaTCP family members in Dn1 under cold stress and demonstrated that TaTCP21-A negatively regulated wheat cold tolerance by inhibiting expression of TaDREB1C. These results provide new insights into the functional mechanism of TaTCP transcription factors in response to cold stress.