盐胁迫响应元件DsADR1调控盐藻GPD累积甘油的作用机制

As a kind of ideal glycogen, Glycerol is widely used in food, medicine and other industries. Dunaliella salina is one of the most salt-tolerance photosynthetic eukaryotic single-celled organisms in the world. Dunaliella can be synthesized in cell dry weight of 30% glycerol, and glycerol synthesis and transformation is used to regulate cellular osmotic pressure. Glycerol 3-phosphate dehydrogenase is a key enzyme in glycerol metabolism, to carry out the glycerol 3 - phosphate dehydrogenase expression Regulation which is important to clarify cells osmotic pressure regulation and high glycerin anabolic mechanism. This pre-project have been cloned Dunaliella chloroplast (OSM DsGPD), cytoplasmic (ct-DsGPD) and mitochondria (mt-DsGPD), three Glycerol 3-phosphate dehydrogenase isozyme gene and its 5 'end flank sequence and the promoter sequence of the gene, and the GPD gene transcription factor DsADR1 genes. The project intends to carry out the DsADR1 activation mechanism of gpd, and the interaction with the 5 'end flank sequence of OSM-DsGPD, and the DsADR1 role in the regulation of glycerol. To determining Dunaliella DsADR1 regulation glycerol 3 - phosphate dehydrogenase gene transcription mechanisms, which can lay a theoretical foundation to clarify the signal transduction signaling pathway of Dunaliella salina under salt stress, the molecular response and glycerol synthesis mechanism.

甘油是一种广泛用于食品医药行业的理想糖原。盐藻细胞可积累30%的甘油，是合成甘油效率最高的真核光合生物。研究甘油代谢关键酶-3-磷酸甘油脱氢酶（GPD）表达调控对揭示盐藻高甘油合成机制具重要意义。前期已克隆定位于叶绿体、胞质和线粒体的3个GPD同工酶基因及其5'端侧翼序列，和gpd基因的转录因子DsADR1基因。研究发现DsADR1与酵母gpd的表达受到激酶Hog1调节不同，推测盐藻DsGPD基因表达可能受DsADR1的直接调控，通过与DsGPD基因的5'端侧翼序列结合启动DsGPD表达；或DsADR1与其他调控因子结合，共同作用于DsGPD基因的5'端侧翼序列启动基因表达。本项目拟开展DsADR1对DsGPD的激活机制，与DsGPD的5'端侧翼序列相互作用，及其调节甘油合成的作用等，确定盐藻DsADR1调控DsGPD基因转录机制，为阐明盐藻甘油合成的信号传导途径和分子应答机制奠定基础。

盐生杜氏藻是目前发现的世界上最耐盐的单细胞真核光合生物，其适应外界高盐环境主要通过甘油的合成与转化来调节渗透压。因此，研究盐生杜氏藻3-磷酸甘油脱氢酶的转录调控阐明真核细胞在盐胁迫下的信号传导途径和分子应答机制具有重要意义。本项目完成了盐藻转录组测序，确定了盐藻在高盐、氧化和高渗胁迫下的表达模式，获得82333个Unigene，为揭示盐藻的耐盐机制提供了大量表达谱数据；获得20余条MAPK、MAPKK和MAPKKK，鉴定获得一条与高盐胁迫响应的MAPK信号级联途径，为进一步揭示盐藻耐盐调控网络奠定了基础；证实盐藻转录因子DsNFYB可以与盐藻DsGPD基因5端侧翼序列相互作用，从而启动DsGPD基因的表达；揭示了盐藻转录调控因子调控DsGPD转录模式，发现转录因子DsNFYB在高盐、氧化和低温胁迫条件下，可能与DsGPDH2基因的诱导表达有关。