氮介导的Bt水稻-害虫-天敌三营养级互作效应及机理

Application of nitrogen fertilizer can promote Bt rice to constantly and steadily express Bt toxic protein, which can highly resist to target pests. While irrational application of nitrogen fertilizer is likely to change the plant traits, making Bt rice subjected to pest damage, and results in outbreak of non-target pest and resistance development of target pests. Additionally, the fitness of natural enemies at the third trophic level would be probably directly or indirectly influenced through the plant chemical information and food chain. Considering that there is a trade-off between the insect resistance of Bt rice and Bt gene expression mediated by nitrogen. Herein, we will focus on the potential issues in the course of the agricultural production, to study the cascading effects of nitrogen rates (0N, 0.5N, 1N, 1.5N and 2N, 1N is the normal nitrogen rate) on the tritrophic interactions, including the resistant trait responses of Bt rice with cry1Ab gene against Lepidoptera or with cry30Fa1 gene against Nilaparvata lugens, the population parameters of target pests (Cnaphalocrocis medinalis or N. lugens), and their predators (Cyrtorhinus lividipennis and Pardosa pseudoannulata). The findings will discover the mechanisms of the tritrophic interactions among Bt rice, pests and natural enemies mediated by nitrogen, and would further clarify the ecological risk of insect-resistant transgenic rice, and would help give instructions for the scientifically-sound cultivation and field management of the insect-resistant transgenic rice in future once it is permitted to commercialization.

施用氮肥可以促进Bt水稻持续稳定表达Bt毒蛋白，对靶标害虫达到高效抗性；另一方面，不合理施用氮肥可能会改变植株性状，使Bt水稻更容易受到病虫的侵袭，导致非靶标害虫大发生，有利于靶标害虫抗性发展，并可能通过化学信号或食物链直接或间接地影响天敌的种群适合度。鉴于氮在Bt水稻的抗虫性和Bt蛋白的表达量之间存在权衡关系。因此，本项目围绕农业生产中可能存在的问题，研究在不同施氮水平下（0N、0.5N、1N、1.5N和2N，其中1N为正常施氮水平），Bt水稻（转cry1Ab抗鳞翅目或转cry30Fa1抗褐飞虱水稻品系）抗性相关特征的响应，以及其对靶标害虫稻纵卷叶螟或褐飞虱种群影响，对捕食性天敌黑肩绿盲蝽和拟环纹豹蛛种群的影响，揭示氮介导的“Bt水稻-害虫-天敌”三营养级相互作用机理，研究结果将有助于进一步明确转基因抗虫水稻的生态风险，未来有助于指导转基因抗虫水稻产业化后科学合理的栽培和田间管理。

施用氮肥可以促进Bt水稻持续稳定表达Bt毒蛋白，对靶标害虫达到高效抗性；另一方面，不合理施用氮肥可能会改变植株性状，使Bt水稻更容易受到病虫的侵袭，导致非靶标害虫大发生，有利于靶标害虫抗性发展，并可能通过化学信号或食物链直接或间接地影响天敌的种群适合度。鉴于氮在Bt水稻的抗虫性和Bt蛋白的表达量之间存在权衡关系。因此，本项目围绕农业生产中可能存在的问题，研究了在不同施氮水平下，Bt水稻抗性相关特征的响应，以及其对主要害虫褐飞虱种群动态和适合度的影响，以及对稻纵卷叶螟种群动态和行为趋性的影响，对捕食性天敌黑肩绿盲蝽捕食功能和行为趋性的影响，揭示氮介导的“Bt水稻-害虫-天敌”三营养级相互作用机理，研究结果将有助于进一步明确转基因抗虫水稻的生态风险，未来有助于指导转基因抗虫水稻产业化后科学合理的栽培和田间管理。