椰扁甲啮小蜂寄生诱导的水椰八角铁甲蛹组织蛋白酶L的表达及其对脂肪体的裂解机制

水椰八角铁甲是危害我国南方棕榈科植物的重大外来入侵害虫，椰扁甲啮小蜂是其蛹期的重要寄生性天敌。抑性内寄生蜂对寄主脂肪体裂解的有效调控是其成功寄生的重要前提，但其调控寄主脂肪体裂解的机制尚不明确。组织蛋白酶L在脂肪体解体过程中扮演重要角色。本项目在前期基础上，以水椰八角铁甲蛹组织蛋白酶L（OncathL）为切入点，通过RNAi等技术鉴定可裂解脂肪体的OncathL；然后从mRNA、蛋白及细胞水平研究啮小蜂寄生对OncathL表达的影响；运用蛋白互作和电镜研究啮小蜂通过OncathL裂解寄主脂肪体基底膜的机制；最后采用双荧光标记法探明啮小蜂局部且循序裂解寄主脂肪体的机理。通过上述研究，揭示椰扁甲啮小蜂通过OncathL裂解寄主脂肪体的机制。研究结果对于全面理解椰扁甲啮小蜂寄生对水椰八角铁甲蛹脂肪体的调控机制、完善寄生蜂-寄主互作的理论体系具有积极意义，同时对生物防治的开展也具有重要意义。

Octodonta nipae is a serious invasive pest of palm plants in South China, and the endoparasitoid Tetrastichus brontispae is a natural enemy of this pest, which shows huge potential in biocontrol of O. nipae pupae. The effective lysis of host fat body is a precondition for successful parasitism, however, only sparse information is available regarding the lysis mechanisms. In the present study, based on the function of cathepsin L in the fat body decomposition and degradation, O. nipae cathepsin L (OncathL) that functions similarly was identified using RNAi, the effects of parasitization by T. brontispae on OncathL from mRNA, protein and cell aspects were analyzed, and the degradation of fat body basement membrane by OncathL was examined by applying the combination of protein interactions and electron microscopy. Furthermore, in view of the development of larval endoparasitoid, the way in gradual dissociation of host fat body was explored by dual immunofluorescence. The integrated results of this study will provide insights into the mechanisms in lysis of host fat body by T. brontispae via expression of OncathL. Taken together, the data will offer invaluable resources for deciphering host fat body regulation by T. brontispae and for completely understanding host-endoparasitoid interaction, and also pave the way for the development of biocontrol of O. nipae.