Identification and characterization of cold-responsive cis-element in the OsPHD13 and OsPHD52 promoter and its upstream regulatory proteins in rice.

Rice (Oryza sativa L.) is one of the most important grain crops in the world. Abiotic stress such as low temperature is an important factor affecting the yield and quality of rice. To explore the endogenous stress-resistant genes and apply them to the breeding of new stress-resistant varieties is an effective way to improve the stress tolerance and adaptability of rice. PHD-finger transcription factor is a kind of zinc-finger structural protein that exists widely in eukaryotes. Its function is mainly focused on gene transcription and regulation of chromatin state, but there are few reports about its involvement in stress response. In the present study, a total of 58 PHD-finger transcription factors were identified, and two genes OsPHD13 and OsPHD52 were significantly up-regulated under low temperature stress. After low temperature induction, GUS driven by OsPHD13 and OsPHD52 promoters had different expression activities in roots, stems and leaves of transgenic plants. Further functional analysis of the pOsPHD13 and pOsPHD52 showed that each of them had a cis-acting element of CRT/DRE in response to low temperature stress. Both in yeast one-hybrid assays and in in vitro gel-shift analysis, CBF protein could specifically bind to the CRT/DRE element in the promoter.