【摘要】 盐藻 (Dunaliellasalina (Chlorophyta) )极强的耐盐能力使之成为研究植物耐盐分子机制的重要模式生物 .在前期分离到的一个盐藻基因片段在盐胁迫时增强表达的基础上 ,通过RACE获得了该基因 5′端cDNA序列及部分 3′端cDNA序列 .序列分析结果表明 ,该基因是一个编码线粒体GIY YIG族归巢内切酶的Ⅰ型内含子基因 .RNase freeDNase处理及Northern杂交结果表明 ,盐藻线粒体DNA在盐处理组中可能发生了扩增 .这些结果结合前人的研究成果说明 ,该内含子基因的增强表达可能并非盐藻对抗盐胁迫的一种手段 ,而是盐藻对抗盐胁迫的副产品 .被该内含子基因插入的基因是盐藻对抗盐胁迫所需要增强表达的 .线粒体DNA的扩增可能是细胞在受到盐胁迫时线粒体数量增加的结果更多还原

【Abstract】 Outstanding salt tolerance ability has made Dunaliella salina (Chlorophyta) an important model organism for clarifying the molecular mechanisms of salt tolerance. An isolated Dunaliella salina gene fragment up expressed under salt stress was studied further. 5′ end cDNA sequence and part 3′ end cDNA sequence were obtained through RACE reaction. The sequence analysis showed that this sequence represented a mitochondrial group I intronic gene coding for GIY YIG family homing endonucleases. Combination of RNase free DNase digestion with Northern blot analysis showed that mitochondrial DNA of Dunaliella salina might be amplified under salt stress. These results suggested that the up expression of this intronic gene might be a by product of the process of salt tolerance, which was unnecessary for the salt tolerance of Dunaliella salina , and that the gene containing this intronic gene might be the genuine gene that needed to be up expressed for salt tolerance of Dunaliella salina . The amplification of mitochondrial DNA might be the result of increasing mitochondria under salt stress.更多还原