Overexpression Of A Kind Of Transcription Factor, OSPHD1, Can Enhance Stress Tolerance In Rice

Drought, low temperature and high salinity are main environmental factors which can significantly affect the plant growth and development. It is crucial to address how to reduce abiotic stress damage and improve the tolerance of plants.Transcription factors can play important roles because they can regulate the expression of many genes belongs to multiple families or pathways. Over-expression of related transcription factors to abiotic stresses in transgenic plants can active or inhibit a number of functional genes involved in response to stresses at the same time and then enhance the stress tolerance in plant. Therefore, it is very importment to study the function of transcription factors involved in Abiotic Stress Resistance in plants.OSPHD1 is a drought and high-salinity inducible gene obtained from a microarray study (Zhou et. al., Plant. Mol. Bol., 2007,63:591-608). By sequence blast on TIGR Rice Genome Annotation Database (http://rice.plantbiology.msu.edu/), OSPHD1 belongs to PHD-finger protein family. In this study,the expression assaying and function of OSPHD1 gene were performed.The main results are as follows:1. Based on semi-quantitative RT-PCR assay, the expression of OSPHD1 was induced by drought, salt and cold treatments. The cDNA length of OSPHD1 is 2067bp.2. By using agro bacterium-mediated transgene technique, OSPHD1 was successfully introduced into rice cultivar Zhonghua 11 (Oryza sativa ssp japonica) and T1 generation of transgenic rice was achieved.Under drought, salt and low tempreture treatment, T1 transgenic plants shows significantly improved stresses tolerance compared with the non-transgenic plants. The stresses resistance phenotype was consistence in T2 plants by analyzing the single-copy homozygous lines, and this was well correlated with the qRT-PCR results. The transgenic lines over-expressed with OSPHD1 did not show abnormal phenotype in field.3. The result of transient expression assay of OSPHD1 gene in onion epidermal cells indicated that OSPHD1 protain locationed in nuclear. In addition, to characterize the transcription activation domain , the yeast two-hybrid system was used, but no trans-activation function was observed.It indicated no trans-activation function in yeast AH109.