拟南芥AtCAO和AtHEMA1基因共表达载体的构建及转烟草研究

Construction of Co-expression Vector Containing AtCAO and AtHEMA1 Genes from Arabidopsis and Transformation into Tobacco

增加作物的叶绿素含量,尤其是叶绿素b的含量,是增强作物耐弱光性的可能途径。将拟南芥叶绿素合成的关键酶——谷氨酰tRNA还原酶(glutamyl-tRNA reductase,HEMA1)的基因和促进叶绿素b合成的关键酶——叶绿素酸酯a加氧酶(chlorophyllide a oxygenase,CAO)的基因,构建于同一个植物双元表达载体,经农杆菌介导整合进烟草基因组。结果显示,弱光下转基因烟草比野生烟草的叶绿素总量增加不显著,但叶绿素b含量增加16%～17%、叶绿素a/b比值降低9%～12%、光合作用增强42%～65%,均达到显著水平,而且生长发育比野生烟草快。为今后改良作物的耐弱光性奠定了基础。

It is a possible way to improve the low light resistance of crops by increasing the amount of chlorophyll, especially that of chlorophyll b. AtHEMA1 and AtCAO from Arabidopsis thaliana were constructed into the binary expression vector pCAMBIA1302. This two genes were introduced into tobacco via Agrobacterium tumefaciens-mediated transformation. Both the amount of chlorophyll b and the rate of photosynthesis were remarkably increased in the transgenic plant lines TL1 and TL2 compared with the wild type tobacco, while the chlorophyll a/b decreased significantly （P 〈 0. 01 ）. The growth of the transgenic tobacco was accelerated compared with the WT under low light. The results had laid a foundation for improving crop low light tolerance with those two genes.