转Bt作物靶标害虫诱导作用的缺失对非靶标害虫的影响及其机理研究

One of the most succeccful fields of the transgenic technology is to control insect pest with genetically engineered crops that express δ-endotoxins (Cry proteins) from Bacillus thuringiensis (Bt).With the wide use of Bt crops around world, Bt crops can effectively control many kinds of target pests and significantly reduce the overall need for pesticide sprays and improve the quality of agri-product. Nevertheless, the long term use of Bt crops has causes many problems, such as the outbreak of non-target pests, which means that some minor pests in non-Bt host crops have become main pests in Bt host crops. Although the drops of insecticide use in Bt crops is the main reason of the outbreak of non-target pests, but other factors such as the changes of nurtrition and phsiology of Bt crops may also play important roles in these phenomena.In this proposal, we establish a model system including Bt cotton, non-Bt cotton, the cotton bollworm (Helicoverpa armigera) which is the target pest and the solenopsis mealybug (Phenacoccus solenopsis ) which is non-target pest, to study the impact of the deficiency of the induction of Bt crop target pest on non-target pest and its mechanism. The content of this proposal includes four parts. The first part is the impact of the deficiency of the induction of cotton bollworm in Bt cotton on the biology and development of solenopsis mealybug. The second part is to study the impact on the population increase of mealybug in lab and field. The third part is the physiological mechanism of above phenomena and the fourth part is the molecular mechanism. The objective of this proposal is to prove a hypothesis that the deficiency of the induction of target pest in Bt crop is a key factor of the outbreak of non-target pest in Bt crop. The result of this proposal will provide a new theory for improving the methods of the risk evaluation of Bt crops.

利用转Bt 基因技术防治害虫是转基因技术利用最成功的领域之一。随着转Bt 作物的大面积、长期种植，虽然对靶标害虫进行了有效的控制，显著减少杀虫剂的使用量，提升了农产品的安全性，但也随之产生了一些问题，特别是非靶标害虫由次要害虫上升为主要害虫、危害加重问题。对于这个重要问题的回答目前主要是从杀虫剂使用量减少等外因来进行解释，尚未从寄主植物营养及生理变化等内在因素来进行解释。为此本项目以转Bt 棉花、棉铃虫、扶桑绵粉蚧作为模式系统，首先研究转Bt 棉花靶标害虫棉铃虫诱导作用的缺失对非靶标害虫扶桑绵粉蚧生长发育及种群增长的影响，然后就棉铃虫诱导作用缺失影响扶桑绵粉蚧生长发育的生理及分子机理进行研究。通过本项目的研究，可以提出一种理论：转Bt 作物靶标害虫诱导作用的缺失是非靶标害虫猖獗的关键因子之一。本项目研究成果将为完善转Bt 作物的安全性评估提供一种新的方法和理论依据，具有重要的科学意义。

利用转Bt 基因技术防治害虫是转基因技术利用最成功的领域之一。随着转Bt 作物的大面积、长期种植，虽然对靶标害虫进行了有效的控制，显著减少杀虫剂的使用量，提升了农产品的安全性，但也随之产生了一些问题，特别是非靶标害虫由次要害虫上升为主要害虫、危害加重问题。对于这个重要问题的回答目前主要是从杀虫剂使用量减少等外因来进行解释，尚未从寄主植物营养及生理变化等内在因素来进行解释。为此本项目以转Bt 棉花、棉铃虫、扶桑绵粉蚧作为模式系统，首先就转Bt棉花靶标害虫棉铃虫诱导作用的缺失对非靶标害虫扶桑绵粉蚧生长发育的影响开展了研究，然后就棉铃虫诱导作用缺失影响扶桑绵粉蚧生长发育的生理及分子机理进行研究。研究结果表明：棉铃虫取食棉花后所诱导的寄主植物反应对扶桑绵粉蚧会产生负面影响，扶桑绵粉蚧幼虫发育历期显著延长，虫体显著变小；通过比较研究后发现，棉铃虫取食棉花后会导致棉花中的棉酚含量显著提高进而导致扶桑绵粉蚧生长发育受到影响，这正是棉铃虫诱导作用缺失影响扶桑绵粉蚧生长发育的生理机制；最后，通过比较分析扶桑绵粉蚧取食寄主植物后对茉莉酸（JA）和水杨酸（SA）代谢途径中相关基因的调控提高其对寄主植物的适应性。转通过本项目的研究成果，可以提出一种理论：转Bt 作物靶标害虫诱导作用的缺失是非靶标害虫猖獗的关键因子之一。本项目研究成果将为完善转Bt 作物的安全性评估提供一种新的方法和理论依据，具有重要的科学意义。