Bt玉米杀虫蛋白含量的时空表达及对亚洲玉米螟的杀虫效果

Temporal and Spatial Expression of CrylAb Toxin in Transgenic Bt Corn and Its Effects on Asian Corn Borer,Ostrinia furnacalis(Guenee)

利用ELISA方法对2个转Cry1Ab基因抗虫玉米品种MON810和Bt11在不同生育期、不同组织器官中杀虫蛋白的表达量进行了分析,利用室内生测方法研究了不同组织器官对亚洲玉米螟初孵幼虫杀虫效果,并分析了杀虫蛋白表达量与杀虫效果的相关性。结果表明,Cry1Ab杀虫蛋白在Bt玉米MON810和Bt11的不同生育期和组织中的表达量呈明显的时空动态变化,以营养生长阶段的心叶组织表达最高,分别为1880.6和1473.1ng·g-1,生殖生长阶段的花粉含量最低,分别为52.3和73.3ng·g-1。随着叶片的生长,叶片中的杀虫蛋白含量明显下降,生殖生长阶段的各组织器官的杀虫蛋白的含量因组织而异。不同Bt玉米品种间同一组织器官的杀虫蛋白表达量也存在一定差异。室内生测结果表明,2个Bt玉米各组织对亚洲玉米螟初孵幼虫具有很好的杀虫效果,心叶、苞叶、雌穗尖和籽粒中Bt杀虫蛋白表达量及取食的幼虫死亡率呈显著正相关,但Bt11花丝以及MON810和Bt11的雄穗中Bt杀虫蛋白的含量与杀虫效果不一致,说明Bt玉米杀虫活性的表达还会受到其它一些因素的影响。

The levels of CrylAb protein expression in two transgenic Bt corn hybrids, MON810 and Bill, were quantified by using enzyme-linked immunosorbent assay (ELIS A) and the efficacy of the Bt corn hybrids on neonates of the Asian corn borer, Ostrinia furnacalis (Guenee), were evaluated in laboratory bioassay. The results showed that the CrylAb protein expressions were varies in different tissues throughout the growing season. The highest level of expression was detected in heart leaves at vegetative stage with 1 880.6 and 1 473.1 ng·g-1, and the lowest in pollen at reproductive stage with 52.3 and 73.3 ng·g-1 in MON810 and Bt11, respectively. The amount of CrylAb protein in leaves decreased as the corn plant development, and varied in different tissues at reproductive stage. Bioassay results indicated that two Bt corn hybrids expressed sufficient Bt protein to kill neonates of the Asian corn borer. The amount of CrylAb protein expressed in whorl leaves, husks, ear tips and kernels of both Bt corn hybrids was highly correlated with the mortality of Asian corn borer neonates, respectively, but not the tassels for MON 810 and tassels and silks of Btl 1, which showed that the resistance of the Bt corn to the insect was also related to other factors.