转cry1Ac玉米对亚洲玉米螟的抗性评价

Evaluating transgenic cry1Ac maize for resistance to Ostrinia furnacalis(Guenée)

目标性状的有效性评价是转Bt基因抗虫玉米研发和安全性评价研究的重要内容之一。采用酶联免疫吸附剂测定(ELISA)、室内生测和田间人工接虫鉴定研究了转cry1Ac玉米纯合群体BT-X和分离群体BT-38、BT-181、BT-43、BT-105等转化事件Cry1Ac蛋白的表达量以及对亚洲玉米螟Ostrinia furnacalis(Guenée)的室内杀虫和田间抗虫效果。转cry1Ac玉米鲜组织中Cry1Ac蛋白含量在44.07～438.00 ng/g之间,不同转化事件及不同组织之间差异显著,其中BT-X鲜花丝中Bt蛋白表达量显著低于未展开心叶。室内生测试验中除BT-43与对照没有显著差异外,取食其它转基因玉米心叶的亚洲玉米螟初孵幼虫6或7天的存活率为0～15.3%,显著低于非转基因对照;取食夏播BT-X鲜花丝6天的幼虫存活率为62.5%,显著低于Bt11及非转基因对照。田间心叶期接虫鉴定显示BT-X高抗亚洲玉米螟。说明转cry1Ac玉米BT-X、BT-181、BT-38和BT-105对亚洲玉米螟有很高的杀虫作用,BT-X田间抗虫效果良好。

Evaluating transgenic Bt maize for resistance to target insect is a key component of research and development as well as the environmental safety assessment of insect resistant transgenic maize. Effi- cacy of transgenic crylAc maize, events BT-X （homozygote） and BT-38, BT-181, BT43, and BT-105 （segregation populations） , expressing CrylAc protein, were evaluated both in the laboratory and in the field for controlling the Asian core borer （ACB）, Ostrinia furnacalis （Guen^e）. Enzyme-linked immu- nosorbent assays was exploited to quantify Cryl Ac protein expressing levels in fresh whorl leaves and silks of transgenic crylAc maize plants. The expression levels of CrylAc protein were significantly different among the events in the whorl leaves and silks, ranged from 44.07 to 438. 00 ng/g fresh weight of the tis- sue. In addition, the expression level of Cryl Ac protein was significantly low in the silk than in the whorl leaves of BT-X. The survival of larvae fed on whorl leaves of all transgenic crylAc maize events, except BT-43, were significantly lower than non-Bt controls, the survival rate ranged from 0.0%-15.3%within 6 or 7 d. However, the survival rate was 62.5% when neonates fed on BT-X silk within 6 d, which was significantly lower than event Btl 1 and non-Bt controls. Damage ratings in the field trials indi- cated that BT-X was highly resistant to ACB. The results demonstrate that transgenic crylAc maize events BT-X, BT-181, BT-38 and BT-105 are high toxicity to the ACB and BT-X offers season long protection against ACB in the field.