陆地棉Bt抗虫基因类型鉴定与染色体定位

摘要

In order to define the inheritance of insect⁃resistant traits, insect⁃resistant gene types and the position of the insect⁃resistant gene on chromosomes in a Bt transgenic cotton germplasm N099, the insect resistance and susceptibility was evaluated in a F2 population of non⁃resistant N099 and resistant Hai7124 ( Gossypium barbadense) . Results showed that the resistance was controlled by a single pair of dominant gene. N099 was identified by Bt protein strip and DNA⁃PCR to contain bivalent Bt insect⁃resistant gene, Cry1Ac+Cry2A. A pair of polymorphic primer NAU2912 two hundred and thirty⁃four pairs of primers covering 26 cotton chromosomes was found in a near⁃isogenic pool consisting of resistant&susceptible F2 cotton plants to be linked with the Bt gene Cry1Ac+Cry2A. Known the primer on cotton chromosome 26, then other prim⁃ers on the chromosome flanking 50 cM from the primer were screened, which received 16 pairs of primers linked with the Bt gene. It was located between SSR marker dc40260 and cgr6702, with genetic distance 1�8 cM and 2�9 cM respectively. Thus, the bivalent Bt gene is mapped on the cotton chromosome 26.%为明确Bt抗虫棉种质系N099的抗虫性状遗传方式、抗虫基因类型以及抗虫基因插入染色体的位置，用N099为父本与非抗虫海岛棉海7124杂交，分析了F2分离世代遗传方式，结果表明该抗虫棉的抗虫性状呈简单的1对显性基因控制的质量遗传方式。进一步在Bt毒蛋白和DNA 2个层面对该抗虫基因类型进行鉴定，结果显示N099所含抗虫基因为双价Bt基因Cry1Ac＋Cry2A。而后利用234对核心引物对F2代抗、感株组成的近等基因混池进行多态性筛选，发现其中1对多态性引物NAU2912与该Bt基因连锁。已知引物NAU2912位于棉花第26染色体上，通过对该引物上、下50�0 cM之间的其他引物进行多态性筛选，共获得16对引物与双价Bt基因相连锁，目的基因位于分子标记dc40260和cgr6702之间，其遗传距离分别为1�8 cM和2�9 cM，因此将双价Bt基因定位在棉花第26染色体上。