转Bt基因棉花中Cry1Ac蛋白经烟粉虱途径向龟纹瓢虫的传递
Transmission of Cry1Ac from transgenic Bt cotton to the predatory ladybug Propylaea japonica via the whitefly Bemisia tabaci
周福才** 顾爱祥 杨益众*** 苏宏华 胡其靖 杨爱民
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DOI：10.7679/j.issn.2095-1353.2015.109
作者单位：扬州大学园艺与植物保护学院，扬州 225009
中文关键词：转Bt基因棉花，烟粉虱，龟纹瓢虫，Cry1Ac蛋白，传递
英文关键词：Bt transgenic cotton, Bemisia tabaci, Propylaea japonica, Cry1Ac, transmission
中文摘要：
【目的】烟粉虱Bemisia tabaci是转基因棉的非靶标害虫，对棉花生产造成严重影响。本文探讨转Bt基因棉花中Cry1Ac蛋白在棉花-烟粉虱-龟纹瓢食物链中的传递规律，以期为转基因棉的环境安全评价提供科学依据。【方法】 在实验室条件下，以常规棉SM3号、33、SY321为对照，分析转Bt基因棉花GK12、XM33B、SGK321叶片、在这些棉花上取食的烟粉虱、以及捕食烟粉虱的瓢虫体内Cry1Ac蛋白含量。同时，将取食转Bt基因棉花上的烟粉虱的瓢虫转接到对应的受体亲本棉花上，分析瓢虫体内Cry1Ac蛋白含量变化规律。【结果】 在转Bt基因棉花上取食的烟粉虱成虫和若虫以及它们的蜜露中均能检测到Cry1Ac蛋白，以转Bt基因棉花上的烟粉虱若虫为食料的龟纹瓢虫体Propylaea japonica内也能检测到Cry1Ac蛋白。龟纹瓢虫取食转Bt基因棉花上的烟粉虱若虫1 d后体内即能检测到Cry1Ac蛋白，并且随着取食时间的延长，体内Cry1Ac蛋白的含量逐渐增加，但到第6~8天后Cry1Ac蛋白的含量相对稳定。取食3个不同品种棉花上烟粉虱若虫的龟纹瓢虫体内Cry1Ac蛋白的含量存在明显差异，这种差异与棉花叶片上表达的Cry1Ac蛋白量呈正相关。但取食后6 d，在3个品种棉花上取食的龟纹瓢虫体内的Cry1Ac蛋白含量之间没有明显的差异。以转Bt基因棉花上的烟粉虱若虫为食料的龟纹瓢虫转移到对应的常规棉亲本上以后，体内的Cry1Ac蛋白的含量迅速下降，但10 d后仍能检测到微量的Cry1Ac蛋白。【结论】 转Bt基因棉花中的Cry1Ac蛋白可以通过烟粉虱途径传递到龟纹瓢虫体内，龟纹瓢虫对食料中的Cry1Ac蛋白具有富集作用，并且Cry1Ac蛋白的富集存在饱和现象，富集饱和量与食料中的Cry1Ac含量无关；龟纹瓢虫脱离含有Cry1Ac蛋白的食料环境后，体内的Cry1Ac蛋白可以消减，但在10 d时间内龟纹瓢虫体内仍会有Cry1Ac残留。
英文摘要：[Objectives] The whitefly, Bemisia tabaci, is an economically important, non-target pest of Bt transgenic cotton. In this study, we examined the transmission of Cry1Ac from transgenic Bt cotton to the predatory ladybug, Propylaea japonica, (a natural enemy of the whitefly) in an effort to better evaluate the ecological safety of transgenic Bt cotton. [Methods] We used an enzyme linked immunosorbent assay (ELISA) to compare Cry1Ac levels in B. tabaci fed on the leaves of the conventional cotton cultivars SM3, SM33, and SY321 to those fed on the Bt transgenic cotton lines GK12, XM33B, and SGK321. [Results] Cry1Ac was detected in the adults, nymphs and honeydew of B. tabaci fed on Bt transgenic cotton. Cry1Ac was also detected in P. japonica that fed on these B. tabaci after just one day of feeding on B. tabaci nymphs that had consumed Bt transgenic cotton. The Cry1Ac content of P. japonica increased with increased with the duration of feeding, then stabilized after 6 to 8 days. The Cry1Ac content of P. japonica differed depending on the transgenic cotton line on which B. tabaci had fed. Although the Cry1Ac content of P. japonica declined when these were no longer exposed to food containing Cry1Ac, it did not disappear completely. The results of this study suggest that Cry1Ac from Bt transgenic cotton can be transferred to P. japonica through B. tabaci, and that B. tabaci can accumulate Cry1Ac. Cry1Ac levels in P. japonica eventually plateau; the speed of Cry1Ac accumulation in P. japonica, but not its saturation capacity, is related to the Cry1Ac content of their food. [Conclusion] Cry1Ac from Bt transgenic cotton can be transferred to P. japonica through B. tabaci, and B. tabaci can accumulate Cry1Ac. Cry1Ac levels in P. japonica plateau after 6 to 8 days; the speed of Cry1Ac accumulation in P. japonica, but not its saturation capacity, is related to the Cry1Ac content of their food.