具有转录激活活性的E3泛素连接酶OsSRFP1调控水稻耐冷性的分子机理研究

申请人前期从水稻中分离了一个胁迫诱导的E3泛素连接酶基因OsSRFP1。OsSRFP1基因的表达受低温等多种非生物胁迫的诱导，其过量表达降低了转基因水稻的苗期耐冷性而RNAi转基因水稻显著提高了耐冷性。OsSRFP1基因表达量下降导致水稻的细胞膜更加稳定，抗氧化性显著增强。有意思的是OsSRFP1除了具有E3泛素连接酶活性以外，也具有转录激活活性，且主要定位于细胞核内，表明OsSRFP1有可能同时也具有转录因子的功能。本研究将在已有基础上深入研究OsSRFP1在低温胁迫下的作用机制，特别是胁迫下OsSRFP1如何行使E3泛素连接酶功能和转录激活功能的研究对于进一步理解植物响应低温胁迫的分子机制具有积极的意义，也为OsSRFP1的育种利用提供理论依据。本研究还将利用基因组编辑技术创制敲除OsSRFP1基因的水稻抗冷新材料，应用于水稻育种实践。

A stress related E3 ubiquitin ligase gene OsSRFP1 was isolated from rice in our previous study. The expression of OsSRFP1 was induced by mutiple abiotic stresses and overexpression of OsSRFP1 decreased cold tolerance while RNAi knock-down of OsSRFP1 increased cold tolerance in rice seedlings. Knock-down of OsSRFP1 stablized the cell memebranes and increased antioxidant activities through moduating gene expression and activities of reactive oxygen species scavaging enzymes. Interestingly, besides having the E3 ubiqutin activity, OsSRFP1 exhibited transcriptional activation activity in yeast and rice cells. Additionaly OsSRFP1 predominately located in the nucleus. These data indicate that OsSRFP1 was also likely a transcription factor. In this study, we will further analyze the molecuar mechanisms for OsSRFP1 in the modulation of cold tolerance, especially the dual roles of OsSRFP1 as an E3 ligase and a transcription activator. Our work will aid in our understanding of the mechanisms for RING finger proteins in cold responses in plants and provide a theory basis for breeding practice with OsSRFP1. The genome edition technology of CRISPR/Cas9 system will be employed to genetically engineer cold tolerant rice by knocking-out OsSRFP1, which could be directly applied in breeding practice.