Bt水稻影响二化螟和螟蛉绒茧蜂间化学通讯的生化机制

The use of insect-resistant GM crops for pest control may affect the chemical communications among plants, pests and natural enemies, and further disturb the natural balance of the farmland ecosystem. This issue has raised certain concerns of the related experts, and it has become a new research direction in the research field of chemical ecology of insects. In order to explore the potential effects of Bt rice planting on the chemical communications between rice plants, rice stem borer Chilo supperssalis (Walker) and the parasitoid Apanteles ruficrus (Haliday), the project applicants have conducted some preliminary studies. The results showed that no difference was found regarding to the behavior responses of Apanteles ruficrus to Bt rice plants and non-transformed plants. However the attraction of the complex of rice stem borer larvae and their feces to the parasitoids was significantly reduced when they fed Bt rice. The findings were consistent with the results reported by a French scientist who had studied on Bt maize. Based on our current results, we are planning to conduct a series of related biological, biochemical and molecular experiments using GC-MS, EAG and PCR-DGGE techniques to clarify the related biochemical mechanisms for explaining the differential responses of Apanteles ruficrus to hilo supperssalis larvae and their feces between Bt treatment and control. The successful implementation of this project will provide deeper understanding regarding the impacts of insect resistant crops on the biodiversity and the mechanisms of the outbreak of secondary pests in fields.

利用转基因抗虫作物防治害虫可能会影响植物-害虫-天敌间的化学信息通讯，进而干扰农田生态系统的自然平衡。该问题已逐渐引起相关专家的关注，成为昆虫化学生态学中一个新的研究方向。为了探索Bt水稻的种植对水稻-二化螟-螟蛉绒茧蜂三营养层间化学通讯的影响，申请人已开展了部分的研究工作，得到与法国科学家报道的有关Bt玉米的相似研究结果：螟蛉绒茧蜂对Bt稻和常规稻的趋性行为反应没有明显差异，但对取食Bt稻的二化螟及其粪便复合体的趋性明显减弱。基于当前的研究结果，本项目拟采用气相色谱-质谱联用（GC-MS）技术、嗅觉仪昆虫行为测定法、昆虫触角电位（EAG）技术及PCR-DGGE指纹分析等方法，开展相关生物学、生物化学和分子生物学试验，揭示螟蛉绒茧蜂对取食Bt稻或常规稻的二化螟及其粪便不同趋性反应的生化机制。项目的顺利实施，将为深入理解抗虫植物的利用对农田生物多样性的影响及次要害虫爆发成灾机制提供科学依据。

本项目研究了转Bt基因水稻的种植对水稻-靶标害虫二化螟-二化螟绒茧蜂三营养层间互作关系的影响及机制。研究发现，外源Bt基因的转入不会影响水稻挥发物的合成和释放，但是当Bt水稻和非Bt水稻相邻种植时，由于非Bt水稻受到靶标害虫较重的危害，释放的信息挥发物相对Bt水稻显著提高，引诱靶标害虫寄生蜂向非Bt水稻田扩散转移，最终导致非Bt稻田寄生蜂种群密度显著高于相邻转基因稻田。另外，结合转录组和代谢组学技术，研究了二化螟危害后水稻在转录水平和代谢水平的动态变化过程，分析水稻中主要初生代谢和次生代谢途径中核心基因和代谢物质差异，揭示了二化螟危害稻株吸引二化螟绒茧蜂的分子机理。本项目的顺利实施，揭示了转Bt基因水稻的种植影响田间靶标害虫寄生蜂种群动态的生态学机制及相应分子机理，为深入理解转基因抗虫植物对农田生物多样性的影响、靶标害虫抗性进化及次要害虫爆发成灾机制提供科学依据。在项目实施过程中，目前共发表学术论文7篇，其中SCI源论文6篇，总影响因子达23，影响因子大于5的SCI论文2篇；培养了2名硕士研究生和2名博士研究生，其中一名博士研究生获得了国家奖学金和大北农励志奖学金。