褐飞虱脂动激素响应水稻营养因子调控生殖的机制

The brown planthopper，Nilaparvata lugens（Stål），is the primary pest of rice production. The population fluctuations and outbreak are the main reasons leading to rice reduction. At present, it is known rice nutrition is the key role of population outbreak, however the regulatory processes and mechanisms is not clear. Blocking AKH/AKHR can inhibit the synthesis of vitellogenin and fecundity.We speculate AKH/AKHR is the environmental signal control of the main mechanisms of the brown planthopper population dynamics. It enable the brown planthopper to sense the environmental pressure, and is involved in basic metabolic and physiological processes. Based on the rice nutrition, our project focus on the AKH/AKHR pathway, which can both induce environment pressure and participate in body basic metabolism. In order to clarify the molecular and ecololgy mechanisms of the population outbreak , the project takes energy metabolism、anti-oxidation and fecundity as index and aims to analyze their functions by using RNAi and pure chemical artificial breeding techniques. The research results can help us to understand more about insect hormorn which regulate the response of N. lugens to environment changes. Also, the results can improve rice cultivating and breeding technology and provide theoretical and technical bases for establishing a more comprehensive management strategy of this pest.

褐飞虱Nilaparvatalugens（Stål）是水稻生产的首要害虫，其波动性的种群大爆发是导致水稻减产的最主要原因。目前已知水稻营养状况是导致褐飞虱种群大突发的关键因子之一，但其调控机制尚不清楚。脂动激素（AKH）是体内基础代谢的重要调节物质，也是一种功能多样的压力激素，是昆虫主要的应激反应调控因子。我们在研究中发现，褐飞虱AKH能响应营养因子的变化，阻断AKH通路能抑制卵黄蛋白合成，推测AKH及其受体（AKHR）通路是褐飞虱响应营养信号、进而调整生存对策的主要途径之一。本项目在功能性验证AKH/AKHR通路的基础上，解析AKH在糖脂代谢、抗氧化应激和生殖中的作用；建立AKH/AKHR响应营养因子调控生殖的基本模型；并对相关的生态因子进行量化和验证。研究结果可进一步揭示褐飞虱响应环境变化的生态过程和生理机制，为深入了解害虫种群爆发的原因提供基础。

本项目从褐飞虱（Nilaparvata lugens）AKH/AKHR通路入手，解析了AKH在糖脂代谢、抗氧化应激和生殖中的作用，建立了AKH/AKHR响应营养因子调控生殖的基本模型。具体的研究结果如下：.1..褐飞虱AKH通路的分子特征和基本功能.脂动激素/受体（Adipokinetic hormone/Adipokinetic hormone receptor，AKH/AKHR)基因的基本分子特征和功能。得到AKH cDNA和AKHR cDNA，命名为NLAKH(未登陆)和NLAKHR(登录号为AHJ11243)。通过激素注射和RNAi，发现AKH正向调控糖脂代谢。.2..蔗糖通过AKH调控取食和代谢.蔗糖通过AKH影响褐飞虱糖脂代谢。蔗糖缺失的条件下，脂质合成相关基因、载脂蛋白、海藻糖代谢相关基因及胰岛素受体底物mRNA表达量均显著下降；此条件下阻断AKH通路后，上述基因的表达量上升。表明AKH通路响应蔗糖水平，调控脂质、海藻糖代谢过程及胰岛素通路。.3..AKH调控褐飞虱卵黄发生.AKH通过调控褐飞虱血淋巴中的海藻糖浓度控制卵巢对卵黄原蛋白的吸收和利用。AKH通过与位于脂肪质膜上的AKH受体(AKHRs)相互作用启动细胞内信号途径，刺激三酰基甘油脂(TAG)分解成二酰基甘油(DAG)，调节能量动员，并将糖原转化为海藻糖，进而调控卵黄蛋白的吸收。.4..AKH通过CncC通路参与褐飞虱抗药性.AKH是褐飞虱抗吡虫啉的一个负调控因子。AKH通过抑制CYP6AY1和CYP6ER1表达降低P450酶活，抑制褐飞虱对吡虫啉的抗性。利用AKH或其类似物抑制褐飞虱对吡虫啉的抗性，可起到吡虫啉增效剂的效应。.AKH响应蔗糖营养因子刺激，调控生殖，以及AKH参与害虫抗药性等研究结果，可为进一步揭示褐飞虱响应环境变化的生态过程和生理机制，为深入了解害虫种群爆发的原因提供基础。