通过cDNARDA法分离和识别盐藻(Dunaliella salina)盐胁迫相关基因

采用cDNA代表性差异分析 (RDA)技术 ,对盐藻在盐胁迫时差异表达的基因进行了分离鉴定 .在分离到的 10个基因中 ,有 5个与已知基因同源 (包括叶绿素a b结合蛋白基因、蛋白磷酸酶I催化亚基基因和 3个核糖体蛋白基因 ) ,还有 5个未知功能基因则是首次在盐藻中被分离 .值得注意的是 ,所有这 5个已知基因的功能都与细胞分裂或盐胁迫有关 .结果表明 :取样时盐藻细胞仍处于恢复阶段 ,所分离到的基因对于盐藻耐盐可能具有重要意义 ;蛋白磷酸酶I的下调表达可能是盐藻调节离子平衡的一个重要过程和细胞分裂受阻的原因所在 ;盐藻减缓细胞分裂速度可能是为了减少能量消耗 ,以留出足够的能量来应对盐胁迫 ;其它 5个未知基因可能也与盐藻适应盐胁迫机制有关 .

Isolation and Identification of Genes Involved in Salt-Adaptation of Dunaliella salina by cDNA RDA

Representational difference analysis of cDNA (cDNA RDA) has been performed to isolate the genes involved in salt-adaptation of D. salina. 11 differentially expressed clones were isolated. Among 10 sequences precisely determined from the clones, 5 sequences were homologues to known genes of other organisms, but the other 5 sequences with unknown function were identified for the first time. Remarkably, all of the 5 known genes, including 3 ribosomal protein genes, PP1 gene, and chlorophyll a/b binding protein gene, are either cell proliferation related or salt-tolerance related. It is suggested that D. salina cells are still in the process of recovering from salt stress at the time of sampling, and the isolated genes might be of importance for salt tolerance of D. salina. The decreased expression of PP1 gene might be an important process of ion homeostasis regulation for D. salina adapting to hyperosmotic shock, and the cause for the suppression of cell proliferation. The possible reason for the slowed proliferation rate of D. salina cell might be to reduce energy consumption to leave more energy to conquer salt stress. The other 5 unknown genes might be involved in salt-adaptation of D. salina also.