农药对飞虱组团（Guild)物种生殖相反效应的分子机理研究

A major challenge in ecology lies in understanding the coexistence of intraguild species. Guild is a frontier research of community and population ecology study, especially in Europe and America. Planthopper guild in rice field including the brown planthopper (BPH), the white-backed planthopper (WBPH) and the small brown planthopper (SBPH) is major devastating pests. Numerous studies on pesticide-induced the stimulation of reproduction of BPH were conducted and some innovative findings were obtained in our previous investigations. However, our recent study found an important and interesting phenomenon: jinggangmycin stimulated the reproduction of BPH but suppressed the reproduction of WBPH, while indoxacarb suppressed the reproduction of BPH but stimulated the reproduction of WBPH. The phenomenon stimulates our research interest. Why planthopper intraguild species with the same or similar niche have inverse effect to pesticide-induced reproductive response. Therefore, we will select 3-5 key genes associated with reproduction and metabolism and used for the gene function by RNAi based on the analysis of gene expression profiles of pesticide-treated BPH, transcriptome of –treated WBPH. The objective is to understand the molecular mechanisms of the inverse effect of pesticide-induced of reproduction of palnthopper guild. The present study has not only important practical significance for accurate application of pesticides (avoid resurgence occurrence of planthopper intraguild species) but also has a theoretical significance for exogenous factor (e.g. pesticides)-induced molecular niche separation of planthopper intraguild species and outbreaks.

生态学主要挑战之一是如何阐明组团内物种的共存问题。物种组团是群落和种群生态学研究的一个前沿研究领域。尤其是欧美国家是很热门的研究领域。稻田飞虱组团（包括褐飞虱、白背飞虱、灰飞虱）水稻毁灭性重大害虫。前期有关农药刺激褐飞虱生殖进行了系统研究，获得了一些创新成果。然而近期我们发现了一个非常重要和有趣的现象—井冈霉素刺激褐飞虱生殖但抑制白背飞虱生殖。而茚虫威抑制褐飞虱生殖但刺激白背飞虱生殖。这一现象激发了我们的极大兴趣。为什么生态位相同或相似的组团物种间具有相反的效应。为此本项目将通过褐飞虱数字基因表达谱、白背飞虱转录组分析，候选出3-5个关键基因进行功能及对应的RNAi雌虫生化测定研究，以其阐明农药诱导的飞虱组团物种生殖相反效应的分子机理。本项目不仅在农药精准使用（避免组团物种内某一物种发生再猖獗）具有重大实践意义，而且对组团物种进化及其种群间此起彼伏猖獗具有重要理论意义。

稻飞虱是一个物种组团，危害严重的主要有褐飞虱（BPH)，白背飞虱(WBPH) 和灰飞虱(SBPH)。飞虱爆发时使用化学药剂是必须的，但化学药剂的不合理使用会导致飞虱发生再猖獗。飞虱再猖獗严重威胁粮食安全。另外在水稻生长期，除了害虫外，病害、草害发生也需要使用药剂。多种药剂（包括杀虫剂、杀菌剂、除草剂）的使用对飞虱组团再猖獗的影响研究不多。据我们前期研究有些药剂对不同种飞虱生殖具有相反效应，因此研究药剂对飞虱生殖反向效应及机理，对害虫再猖獗机理阐明及药剂的科学应用具有重要意义。本项目主要研究内容包括对三种飞虱生殖反向效应的药剂混合或先后处理对生殖的影响；反向效应药剂处理的飞虱基因表达谱、蛋白组分析，找出关键基因；在蛋白组分析基础上对关键基因进行功能证实研究，相关基因进行RNAi。研究表明三唑磷刺激三种飞虱生殖，多菌灵刺激灰飞虱生殖，而井冈霉素抑制白背飞虱和灰飞虱生殖。基因表达谱及蛋白组分析显示井冈霉素(JGM)处理的灰飞虱LCHAD显著下调表达，而多菌灵(CBM)处理组HSD显著上调表达。RNA 干扰试验证实对照灰飞虱dsLCHAD 组产卵量下降53%，CBM处理的雌成虫RNA干扰CBM-TF+dsHSD组产卵量下降73%。三种药剂相互混合处理均显著增加了灰飞虱生殖，如冈霉素+多菌灵混合处理灰飞虱单雌产卵量增加了28.95%（140粒增加至180粒），但冈霉素+三唑磷混合处理抑制了灰飞虱生殖，单雌产卵量减少了58.5%（从142.1下降到58.9）；另外先喷井冈霉素后喷三唑磷和先喷井冈霉素后喷多菌灵均显著降低了灰飞虱产卵量，分别下降45.2%（从142.1下降到77.1）和25.5%（从142.1下降到105.9）。这些结果对稻田飞虱组团或病虫害系统科学用药具有重要意义。如在白背飞虱或灰飞虱发生时可以先用井冈霉素防治纹枯病，可以抑制白背飞虱和灰飞虱发生。