CsICE1and CsCBF1: Two Transcription Factors Involved In Cold Responses In Camellia Sinensis

CBFs (C-repeat/dehydration-responsive element binding factors) can induce theexpression of a suite of cold-responsive genes to increase plant cold tolerance, and ICE1(Inducer of CBF expression) is a major activator for CBF. Our study is to elucidate themolecular basis and regulatory mechanisms of tea plant cold responses and enhance the teaplant cold tolerance. Besides, the studies provide with theory basis in molecular biologyabout identification and breeding for cold resisting varieties of tea.We isolated the full-length cDNAs of ICE1and CBF from Camellia sinensis,designated as CsICE1and CsCBF1, respectively. The deduced protein CsICE1contains ahighly conserved basic helix-loop-helix (bHLH) domain and C-terminal region ofICE1-like proteins. CsCBF1contains all conserved domains of CBFs in other plant speciesand can specifically bind to the C-repeat/dehydration-responsive element (CRT/DRE) asconfirmed by electrophoretic mobility shift assay. The transcription of CsICE1had noapparent alteration after chilling treatment (4℃). CsCBF1expression was not detected innormal temperature (20℃) but was induced immediately and significantly by lowtemperature (4℃).Our results suggest that ICE1-CBF cold-response pathway is conserved in tea plants.CsICE1and CsCBF1, two components of this pathway, play important roles in coldresponses in tea plants.