集胞藻PCC6803脂肪酸脱饱和酶基因desD在转基因水稻中的表达

Expression of Fatty Acid Desaturase Gene desD from Cyanobacterium Strain PCC6803 in Transgenic Rice(Oryza sativa)

为了提高水稻的耐冷性,从集胞藻PCC6803中克隆酰基脂肪酸脱饱和酶基因desD与植物表达载体pCAMBIA1301连接,构建了重组质粒pCdesD.采用农杆菌介导的水稻愈伤组织转化系统将desD基因成功地导入粳稻中花11号和朝鲜的平壤21号中,获得一批转基因植株.经PCR检测和Southern杂交分析,证明外源基因已导入并整合到水稻的基因组中;分子检测外源基因单拷贝整合的转化体在T1代呈现3∶1的分离.Northern杂交结果表明该基因在mRNA水平上获得表达.低温胁迫处理后,对转基因水稻进行脂肪酸成分和光合生理分析,结果表明转基因水稻提高了不饱和脂肪酸含量,光合生理也得到了改善,水稻的耐寒能力明显增强.

A recombinant vector pCdesD was constructed by ligation of a fatty acid desaturase gene, desD, isolated from Cyanobacterium strain PCC6803 into the pCAMBIA1301 for rice transformation to increase its cold resistance. The desD gene was transformed into a Chinese cultivar Zhonghua11and a Korea cultivar Pyongyang21 by Agrobacteriurn-mediated rice callus transformation system, and many transgenic rice plants were obtained successfully. The results of the PCR and Southern blotting analyse from transgenic rice plants had shown that the target gene was integrated into transgenic rice genome, and the transgenic rice plants with a copy of exotic gene were segregated into positive and negative individuals as the ratio of 3： 1 in the T1 generation. Northern blotting analysis illustrated further that exotic desD expressed normally at the level of RNA. Compared with the non-transgenic control, the transgenic rice plants increased the content of desaturated fatty acids, improved the photosynthesis, and exhibited better chilling tolerance under low temperature treatment. It is the first report that rice was successfully transformed by fatty acid desaturase gene desD derived from Cyanobacterium strain PCC6803 and improved remarkably its cold-resistance ability.