绿盲蝽取食植物和昆虫的消化酶活性变化及调控机制

Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) has become one of the most important insect pests on cotton and other crops in China in recent years. Our previous studies indicate that A. lucorum is a phytozoophagous insect, which not only feeds on host crops, but also preys on insect pests with an important role for suppressing the populations of cotton bollworm, cotton aphid, whitefly and many other insect pests in agricutural system. In this proposal, we plan to investigate the relationship between digestive enzyme change in the salivary glands and midgut and hosts fed by the insect. Firstly, we try to quantify the activities of different digestive enzymes (including amylase, pectolyase and several proteinases) in the salivary glands and midgut of different A. lucorum populations which feed on plant, insect, and the mixture of plant/insect, respectively. Secondly, based on the cDNA library of salivary glands and midgut of A. lucorum constructed using SMART technique, we will clone the main digestive enzyme genes and analyze their complete nucleotide sequences and expression level in salivary glands and midgut of A. lucorum, while they feed on different food combinations (i.e. different ratio of the amount of plant and insect).These studies are meaningful for further understanding nutritional and metabolic mechanism of this phytozoophagous insect species, which is much valuable for exploring its host adaptability.

近年来绿盲蝽已成为棉花等多种作物上的重大害虫。我们的研究表明，绿盲蝽具有植食性和肉食性的特点，在危害农作物的同时还可通过捕食棉铃虫、棉蚜和烟粉虱等多种害虫，来抑制它们的种群发展。本项目拟分析取食植物、昆虫、植物和昆虫3种食物的绿盲蝽唾液腺与中肠消化酶的种类组成和活性，明确取食不同类型食物的绿盲蝽消化酶变化规律；克隆主要消化酶的基因、获取全长序列，测定取食不同类型食物对相关基因表达的诱导作用，阐明食物对绿盲蝽消化酶分泌的调控机制。研究结果对进一步解析杂食性促进绿盲蝽发育与生殖作用的营养代谢原理，探明绿盲蝽种群寄主适应性进化的机理有着重要的科学意义。

绿盲蝽具有取食植物和昆虫的特性，一方面危害农作物，另一方面可通过捕食棉铃虫等抑制害虫的种群发展。本项目研究了取食植物、昆虫、植物和昆虫三种食物绿盲蝽的行为和消化酶活性，克隆了卵黄原蛋白基因并分析了不同食物对基因表达的调控作用，测定了交配对绿盲蝽卵巢发育及生殖的影响。.结果表明绿盲蝽喜欢取食由植物和昆虫组成的混合食物，但取食植物的时间远长于取食昆虫。取食植物的绿盲蝽淀粉酶活性最高，而取食昆虫的绿盲蝽类胰蛋白酶活性最强。取食混合食物的生殖力最高，而取食昆虫的最低。绿盲蝽卵黄原蛋白基因（Vg）cDNA全长6131bp，开放阅读框长度为5988bp，共编码1996个氨基酸，预测分子量为218.3kDa。不同类型食物处理绿盲蝽Vg基因的表达有显著的差别，取食混合食物绿盲蝽雌虫Vg基因表达量显著高于取食植物或昆虫。交配对绿盲蝽雌虫的卵巢发育和产卵有明显的促进作用，未交配绿盲蝽卵巢内卵黄蛋白被吸收而导致卵子退化。研究结果对进一步解析杂食性促进绿盲蝽发育与生殖作用的营养代谢原理，探明绿盲蝽种群寄主适应性进化的机理有着重要的科学意义。