香梨优斑螟与腐烂病协同为害的化学生态机制

Euzophera pyriella and Valsa ceratosperma are the most important boring insect pest and diseases.There is a synergistic effect between them In the same field distribution. Especially, When freezing injury occurring,the synergistic damage or even lethal to fragrant pear causedby the interaction of both Euzophera pyriella and Valsa ceratosperma, becoming more and more increasingly serious in recent years, has the latent threat to fragrant pear industry and farmland shelterbelts in Xinjiang. In this study, the synergistic mechanism of Euzophera pyriella and Valsa ceratosperma are explored from the point of view of chemical ecology. In order to make clear the ecological functions on Euzophera pyriella of pathogen-induced release of plant volatiles by Valsa ceratosperma, the researches of specific components of pathogen-induced volatiles and their roles on Euzophera pyriella oviposition preference and feeding behavior and so forth are carried out. Based on analysis of species and physiological activities of extracellular enzymes, chemical composition deviation of non-structural soluble carbohydrates of host plant with fungal infection and its influence on nutritional catabolism of Euzophera pyriella are studied. In order to explore plant-mediated interactions and understand ecological and physiological mechanism of synergistic effect of nutrition metabolism between insects and phytopathogenic fungi, we carry out further studies on which the compounds of frass and secretions deposited by larvae of Euzophera pyriella in tunnels and specific volatiles from bore-induced host plant may provide a medium for the rapid growth of fungi and increase infection. Through the implementation of this research project, it helps develop a new pathway and approach based on non-harmful ecological management to control the synergistic damage of phytopathogen and phytophagous pests in this area, and lay the foundation for further revealing chemical-ecological mechanism of serious disaster caused by Euzophera pyriella and Valsa ceratosperma.Meanwhile, it can lead us a deeper understanding of coevolution based on phytopathogen-host plant-phytophagous insect system.

香梨优斑螟与腐烂病同域发生时相互关联、协同为害，且香梨冻害能够促进二者的同步爆发，已对新疆特色香梨产业及生态防护林构成严重威胁。本项目从化学生态学角度开展香梨优斑螟和腐烂病协同为害的机制研究，通过腐烂病菌侵染寄主植物诱导释放挥发物对香梨优斑螟生态作用的探索，明确病菌诱导挥发物的特异性及其在香梨优斑螟产卵、取食等行为中的作用；在分析病菌胞外酶组成和对寄主植物生理活性基础上，通过研究病菌侵染寄主引起的植物组织非结构可溶性化合物组分和含量变化对香梨优斑螟营养代谢的影响，以及香梨优斑螟蛀道内的分泌物和诱导寄主植物释放的特异性化合物对腐烂病菌孢子萌发与侵染发病的影响，探讨由寄主植物介导的虫病间的相互作用，理解二者基于营养代谢协同发生的生理生态机制。该研究有助于揭示香梨优斑螟和腐烂病协同为害的化学生态机理，为农林有害生物治理提供新的途径，对丰富植物病原菌-植物-植食性昆虫体系的协同进化理论有重要意义。

已有调查显示香梨优斑螟与腐烂病同域发生时相互关联、协同为害，但机制仍不十分清楚。本研究采用田间调查、运用生理学和化学生态学等技术手段，对二者发生过程中的相关作用的生态学机制进行了初步研究。首先系统调查明确了香梨优斑螟与腐烂病在时空分布上具有一定的同步相关性；进一步研究明确了腐烂病菌侵染腐烂病菌侵染可改变寄主挥发物的变化及可溶性淀粉和游离氨基酸等物质总量的增加，有利于香梨优斑螟成虫产卵对寄主的选择性及其幼虫的生长发育；采用固相微萃取法、GC-MS和触角电位EAG法对感病果实和树皮处理挥发物进行组分分析和活性测定的结果显示香梨优斑螟2日龄未交配蛾对己酸乙酯、辛酸乙酯、异戊醇、2-苯乙醇、1-辛醇等化合物的反应较强烈，已交配雌成虫反应强于雄虫，与挥发物作为信号引起香梨优斑螟成虫的产卵选择行为相一致。香梨优斑螟分泌排泄物和钻蛀碎屑可促进病菌侵染和病斑的快速扩展。综上结果，本研究为进一步探索香梨优斑螟与腐烂病同域协同发生为害的机制提供了工作基础，对探讨植物病原菌-植物-植食性昆虫体系的协同进化有重要启示。项目执行过程中完成学术论文及会议论文4篇、学术著作2部、获授权软件著作权3项、实用新型专利3项。