调控FAD2不同剪接体参与膜脂和储藏脂合成的机制研究

项目名称： 调控FAD2不同剪接体参与膜脂和储藏脂合成的机制研究

项目编号： No.31470349

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 单雷

作者单位： 山东省农业科学院

项目金额： 80万元

中文摘要： 脂肪酸去饱和酶FAD2在膜脂和储藏脂合成中具有重要作用。植物中不同拷贝的FAD2基因存在表达模式的差异和功能分工，其调控可发生在转录、转录后或翻译后水平，但具体的机制尚不十分清楚。我们前期研究发现，花生AhFAD2A和AhFAD2B的剪接异构体A2和B2主要在种子中表达，可能参与储藏脂合成，并且初步确定1个种子特异性表达的bHLH转录因子与它们的调控区存在相互作用；而A4和B4为组成型表达，推测可能参与膜脂合成。本研究拟深入分析常温和低温处理下普通油酸含量花生和高油酸突变体不同剪接体的表达模式，结合膜脂和储藏脂脂肪酸组成的分析，初步明确它们的功能分工；进一步克隆调控不同剪接体表达的转录因子基因，详细分析它们的表达及转录激活特征、亚细胞定位和结合位点，并通过花生和拟南芥转基因功能鉴定，明确FAD2表达的关键调控因子。初步阐明不同剪接体参与膜脂和储藏脂合成的调控机制，为花生高油酸育种奠定基础。

中文关键词： 转录因子；脂肪酸去饱和酶FAD2；脂类合成；分子机制；花生

英文摘要： FAD2 plays an important role in the synthesis of membrane lipid and storage lipid of plant cells. The different copy of FAD2 gene in plant genome has different expression pattern and function, and its regulation can occur at the transcriptional, post-transcriptional or post-translational level, but the specific regulatory mechanism of it is not yet clear until now. Our previous study found that the isoform A2 of AhFAD2A and isoform B2 of AhFAD2B, which may be involved in the synthesis of storage lipid, mainly express in the developing seeds, and a bHLH transcription factor with a seed-specific expression profile can interact with the regulatory regions of them, while isoform A4 and B4 express constitutively, suggesting that they may be associated with membrane lipid synthesis. In this study, we intend to deeply investigate the expression profile of different FAD2 isoforms of both peanut variety with general content of oleic acid and its mutant with high content of oleic acid treated by room temperature and low temperature, and, based on analyzing of fatty acid composition of both membrane lipid in leaves and storage lipid in seeds, preliminarily make a clear of functional divergence of the isoforms. Furthermore, we want to clone the genes of regulatory factors interacting with the regulatory regions of different FAD2 spliceosomes, and to analyze their expression patterns and transcriptional activation characteristics, subcellular localization, and the binding sites with regulatory regions, and identify their functions through transgenic research in both peanut and Arabidopsis, and define the key regulatory factors of FAD2 gene. Finally, the regulatory mechanisms of different isoforms in the synthesis of membrane lipid and storage lipid will be preliminarily clarified, and the molecular biology theory of fatty acid metabolism be enriched, and a foundation for the high oleic acid peanut breeding be made.

英文关键词： transcription factor;fatty acid desaturase FAD2;lipid synthesis;molecular mechanism;peanut