棉铃虫口器分泌物的系统分析和效应子分离

Plants use plasma-membrane-localized pattern-recognition receptors (PRRs) to detect pathogen-associated molecular patterns (PAMPs) and trigger innate immunity, whereas pathogens have evolved effectors that are delivered into plant cells to counteract plant immune response. PRRs also recognize herbivore-associated molecular patterns (HAMPs) to induce defense response to insect attacking. Although great progresses have been achieved in characterizing pathogenic effectors, our understanding of insect effectors and their functional role is limited (Hogenhout and Bos, 2011). Our lab is engaged in the research of plant-insect interactions. Cotton bollworm is a general herbivore that damages to various crops. Cotton plants accumulate high concentration of gossypol to defense pathogen invading and insect attack but gossypol possesses less effect on bollworm growth. We identified a bollworm P450 (CYP6AE14) that is required for gossypol tolerance. We also found that bollworm can use gossypol to induce the expression of detoxification genes expression and elaborate their tolerance to toxins in diet. Besides improving detoxification ability dose bollworm have other strategies to conquer plant defense? In our recent investigation, we found that oral secretions of cotton bollworm (Helicoverpa armigera) could attenuate the plant response to mechanical wounding. In this project, we shall perform a detailed investigation of cotton bollworm oral secretions (OS), including analyzing the OS components by LC-MS and isolate the effector proteins, and dissecting their function and mechanism in affecting (or cross-talking with) plant defensive responses and the molecular mechanism underlying.

昆虫口器分泌物（oral secretions,OS）中含有丰富的植物-昆虫互作识别的因子（激发子和效应子成分）,在昆虫与植物的互作中发挥重要作用。目前对昆虫OS组分及其生物学功能尚缺乏系统的研究。虽然对于激发子的研究取得了一定进展，但迄今对昆虫OS中的效应子了解还很少。仅在少数昆虫OS中发现了类似效应子的活性成分。棉铃虫是危害多种农作物的广食性昆虫。我们前期实验发现,亚洲棉铃虫（Helicoverpa armigera）OS能干扰植物对机械损伤的应答。本研究拟系统分析鉴定棉铃虫OS蛋白组分, 建立一套高质量的棉铃虫OS蛋白成分信息数据库；分离、鉴定棉铃虫OS效应子，解析效应子在植物-昆虫信息交流中的作用机制，为发展新的抗虫策略提供理论依据。

昆虫口器分泌物（oral secretions,OS）中含有丰富的植物-昆虫互作识别的因子（激发子和效应子成分）,在昆虫与植物的互作中发挥重要作用。目前对昆虫OS组分及其生物学功能尚缺乏系统的研究。虽然对于激发子的研究取得了一定进展，但迄今对昆虫OS中效应子的了解还很少。仅在少数昆虫OS中发现了类似效应子的活性成分。棉铃虫是危害多种农作物的广食性昆虫。本项目以亚洲棉铃虫（Helicoverpa armigera）为对象，分离能够作用于植物防御应答体系的棉铃虫OS蛋白组分，解析效应子干扰植物抗虫防御响应的作用机理。通过对棉铃虫OS蛋白组分的质谱分析，我们发现了OS中的一类R型毒液样蛋白，HARP1和HAS1。毒液蛋白在寄生蜂中具有抑制动物宿主免疫响应的作用。我们发现，棉铃虫中的这类R型毒液样蛋白可以通过昆虫取食，从叶片伤口直接进入植物细胞，并定位于细胞核。其中，HARP１能够与茉莉素信号途径的多个JAZs阻截蛋白发生互作，阻碍JAZs依赖于COI1的泛素化降解，从而抑制JA信号的输出。而HAS1 可以与多种bHLH类转录因子发生互作，包括模式植物拟南芥中的MYC3和MYC4以及棉花中决定腺体形成和次生代谢主要调控因子PGF。HAS1通过与bHLH类转录因子互作，抑制了这类转录因子对下游防御基因的转录活性，从而抑制植物的防御响应。综上，在昆虫取食植物的过程中，其口器分泌中的R型毒液样蛋白，通过双重抑制模型，最大限度的抑制植物防御响应，帮助昆虫更好的适应宿主植物。