转Bt基因抗虫棉Bt基因表达的时空动态

以转Bt基因抗虫棉 33B为材料 ,利用ELISA检测方法 ,通过对棉株不同发育时期和同一时期的不同组织或器官Bt晶体蛋白含量的测定 ,研究了转Bt基因抗虫棉Bt基因表达的时空变化。结果表明 ,随着棉株生育进程的推进和株体的老化 ,Bt晶体蛋白含量随着植株体内可溶性总蛋白含量的逐渐降低而降低 ,而Bt基因的表达强度从苗期到蕾期随着棉株营养生长的加快而呈上升趋势 ,至蕾期达到高峰 ,以后逐渐减弱。不同组织或器官Bt晶体蛋白的含量也有较大差异 ,表现在幼嫩组织或器官的含量较高 ,成熟组织或器官次之 ,衰老组织最低。这说明Bt基因表达强度的减弱和Bt晶体蛋白含量的降低是转Bt基因抗虫棉生育后期抗虫性降低的根本原因

Temporal and spatial dynamics of Bt gene expression in Bt transgenic cotton

Temporal and spatial dynamics of Bt gene expression in Bt transgenic cotton was studied by testing the Bt crystal toxin protein in different growing stages and tissues or parts of plant The results showed that the content of Bt crystal toxin protein in plant decreased gradually as total dissoluble protein decreased in the advance of growth and ageing But the expression index (ratio of Bt crystal toxin protein to total dissoluble protein) of Bt gene increased from seedling to square stage, and then decreased gradually The expression of Bt gene was also various in different tissues or parts of plant The content of the protein was higher in young and tender tissue or part, lower in adult tissue or part, and lowest in aged tissue or part The order was as follows: young square, young leaf>young boll, adult leaf, flower>aged leaf The basic reason of the resistance of Bt transgenic cotton to cotton bollworm changing temporally and spatially in cotton developmental processes was the decrease of Bt gene expression and Bt crystal toxin protein content