Overexpression of a New Zinc Finger Protein Transcription FactorOsCTZFP8Improves Cold Tolerance in Rice

Cold stress is one of the most important abiotic stresses in rice. C2H2zinc finger proteins play important roles in response to abiotic stresses in plants. In the present study, we isolated and functionally characterized a new C2H2zinc finger protein transcription factorOsCTZFP8in rice.OsCTZFP8encodes a C2H2zinc finger protein, which contains a typical zinc finger motif, as well as a potential nuclear localization signal (NLS) and a leucine-rich region (L-box). Expression ofOsCTZFP8was differentially induced by several abiotic stresses and was strongly induced by cold stress. Subcellular localization assay and yeast one-hybrid analysis revealed that OsCTZFP8 was a nuclear protein and has transactivation activity. To characterize the function ofOsCTZFP8in rice, the full-length cDNA ofOsCTZFP8was isolated and transgenic rice with overexpression ofOsCTZFP8driven by the maize ubiquitin promoter was generated usingAgrobacterium-mediated transformation. Among 46 independent transgenic lines, 6 single-copy homozygous overexpressing lines were selected by Southern blot analysis and Basta resistance segregation assay in both T1and T2generations. Transgenic rice overexpressingOsCTZFP8exhibited cold tolerant phenotypes with significantly higher pollen fertilities and seed setting rates than nontransgenic control plants. In addition, yield per plant ofOsCTZFP8-expressing lines was significantly (p<0.01) higher than that of nontransgenic control plants under cold treatments. These results demonstrate thatOsCTZFP8was a C2H2zinc finger transcription factor that plays an important role in cold tolerance in rice.