捕食性天敌南方小花蝽适应不同食物的分子机制

Orius similis Zheng (Hemiptera: Anthocoridae) is widely distributed in cotton fields, orchards, vegetables and other habitat in south China which is one of the important predatory natural enemy. It mainly feed on small insects in nature, but with years of mass rearing in the lab we found that this bug can finish the generation with laying eggs by feeding only plant foods (e.g., pollen, plant juices, honey dew, etc.), and its fecundity is not significantly reduced. This project intends to feed O. similis with plant foods (pollen), animal original foods (aphis) and artificial food, respectively. Combining with the differences characteristics of its growth and development，we plan to screen the differential expressed gene/protein using the methods of digital gene expression profile and comparative proteomics among the different treatments. Then, we plan to identify the candidate food utilization associated genes, analyze its expression patterns, and clone the full-length cDNA sequences of main candidate food-utilization-associated genes using RACE, qRT-PCR and other approaches. Finally, a set of RNA interference system will be established to analysis the function of the main candidate food-utilization-associated genes, to explore the key factors of the developmental control function and its regulation mechanism of O. similis fed with different sources of foods, and to elucidate the molecular mechanisms of O. similis adapted to different sources of foods.

南方小花蝽（Orius similis Zheng）（半翅目：花蝽科）是广泛分布于我国南方棉田、果园、蔬菜地等多种生境中的一种重要捕食性天敌。该虫在自然界以捕食微小昆虫为主，但申请者在多年的人工饲养中发现，在室内人工饲养条件下，南方小花蝽可仅通过取食植物源食物（如花粉、植物汁液、蜜露等）完成世代发育并产卵，且其产卵量并没有因此而显著降低。本项目拟分别用植物源食物、动物源食物（蚕豆蚜）及两者混合的人工饲料分别饲喂南方小花蝽，结合其生长发育特点的差异，采用数字基因表达谱和比较蛋白质组学技术，分析不同条件下南方小花蝽体内的基因/蛋白差异表达，筛选食物利用相关基因。同时，采用RACE、qRT-PCR等技术，鉴定候选基因并分析表达模式、克隆主要候选基因cDNA全长序列，并建立RNA 干扰体系分析主要候选基因功能，以探究南方小花蝽取食不同来源食物后对其生长发育调控发挥作用的关键因子及其调控机制。

南方小花蝽Orius strigicollis是一种重要的天敌昆虫，能够捕食多种害虫及虫卵，如蚜虫、粉虱、蓟马和鳞翅目昆虫的卵等。本项目基于南方小花蝽的食性特点，在饲喂其植物源食物、动物源食物以及混合食物条件下，其生物学特性的某些方面存在显著差异；通过对取食植物源食物和动物源食物的南方小花蝽进行RNA-seq转录组测序和iTRAQ蛋白组测序并联合分析，探究了南方小花蝽为适应不同食物其生长发育调控发挥作用的关键因子，筛选出了六种南方小花蝽取食、消化和代谢酶系家族的关键蛋白：脂肪酸合成酶（fatty acid synthase，FAS）、糖原磷酸化酶（glycogen phosphorylase，GP）、组织蛋白酶D（Cathepsin D，CTSD）、（a-N-acetylgalactosaminidase，NAGA）和脂肪酶（Lipase，LPS），利用RACE、qRT-PCR等技术对候选基因进行表达模式分析、cDNA全长序列克隆，随后建立RNA干扰体系分析主要候选基因功能；综合分析其生物学指标和分子指标的组织蛋白酶L（Cathepsin L，CTSL）、α-N-乙酰半乳糖胺酶差异，本项目的研究结果为解析杂食性昆虫食性转换的生理机制提供了重要参考，并为南方小花蝽这一杂食性天敌昆虫的开发应用提供了重要的理论基础。