Bt毒蛋白在转基因抗虫玉米中的表达及在亚洲玉米螟中的转移积累

以两个转Bt基因抗虫玉米品系G03-2396、G03-2739和对照玉米品种苏玉16为材料，采用室内生物测定法研究它们对亚洲玉米螟的抗性, 并采用酶联免疫技术（ELISA）检测这两个转基因玉米品系不同组织中Bt毒蛋白的表达量及亚洲玉米螟3龄与5龄幼虫取食转基因玉米后体内和粪便中的Bt毒蛋白含量.结果表明：转Bt基因抗虫玉米心叶对玉米螟幼虫的毒性较强，初孵幼虫取食6 d后的存活率不到3%，3龄幼虫取食6 d后的存活率小于70%，抗虫玉米雌穗的毒性小于心叶.两个转Bt基因玉米心叶和雌穗中均表达了一定量的Bt毒蛋白，但心叶中的毒蛋白含量高于雌穗；Bt毒蛋白表达量依次为G03-2739心叶（39.6 μg·g^-1FM）> G03-2396心叶（26.1 μg·g^-1 FM）> G03-2396雌穗（17.0 μg·g^-1 FM）> G03-2739雌穗（14.6 μg·g^-1 FM）.取食转基因玉米心叶或雌穗后，3龄幼虫体内的Bt毒蛋白含量显著高于5龄幼虫；同龄幼虫取食心叶后其体内及粪便中Bt毒蛋白含量均显著高于取食雌穗的个体.其中,取食G03-2739心叶的5龄幼虫粪便中的Bt毒蛋白含量最高，达10.4 μg·g^-1 FM；取食其雌穗的3龄幼虫粪便中的Bt毒蛋白含量最低，仅2.7 μg·g^-1 FM.

Bt toxic protein expression in insect-resistant transgenic corns and its transfer to and accumulation in Ostrinia furnacalis

Taking the insect-resistant transgenic corn varieties G03-2396 and G03-2739 and the conventional corn variety Suyu 16 as test materials, a bioassay in laboratory was conducted to test their resistance against  Ostrinia furnacalis. The Bt toxin expression in different tissues of the two transgenic corns, the ingestion of  Bt  toxin by the 3rd and 5th instar of O. furnacalis, and the  Bt  toxin amount in feces of O. furnacalis larvae fed with  Bt  corns were analyzed by using enzyme-linked-immunosorbent-assay (ELISA). It was found that the central leaves of both G03-2396 and G03-2739 had great toxicity to O. furnacalis larvae. After fed with the central leaves for 6 d, the survival rate of neonate larvae was less than 3%, and that of the 3rd instar larvae was less than 70%. Female ears had smaller toxicity than central leaves. The  Bt  toxic protein was detected both in the leaves and in the female ears of the two transgenic corns, but its content was higher in central leaves than in female ears. The Bt  toxic protein expression level was in  order of G03-2739 central leaf (39.6 μg·g^-1 FM) > G03-2396 central leaf (26.1 μg·g^-1 FM) > G03-2396 female ear (17.0 μg·g^-1 FM) > G03-2739 female ear (14.6 μg·g^-1 FM). When fed with central leaf or female ear, the  Bt toxic protein amount in the 3rd instar larvae was significantly higher than that in the 5th instar larvae. For the same age instar larvae, the  Bt  toxic protein content was significantly higher after fed with central leaf than fed with female ear, so did the  Bt toxic protein content in larvae feces, being the highest (10.4 μg·g^-1 FM) for the 5th instar larvae fed with G03-2739 central leaf, and the lowest (2.7 μg·g^-1 FM) for the 3rd instar larvae fed with G03-2739 female ear.