番茄对东亚小花蝽产卵的响应及其对西花蓟马种群动态的影响机制研究

Orius sauteri is a kind of important predatory natural enemy. It preys on aphid, whitefly, thrips and small Lepidoptera pests, which is one of the preponderance natural enemies in bad demand and has vital biological control function. However, the oviposition behavior of Orius restricts their mass rearing. They oviposite in petiole and vein of young leaves, resulting in the difficulty in changing substrate plants and controlling nutrition. The ovipositing behavior also causes mechanical damage visible to naked eyes. Plant resists the infection of plant diseases, insect pests and mechanical damage via systematical defence response. Thus it is essential to study the interactions between the oviposition behavior and plant defence responses. Previous studies by the applicant have found that Frankliniella occidentalis and Bemisia tabaci tend to avoid the plants in which Orius had laid eggs. However, whether it is due to the accumulation of plant defence signaling substances remains to be further studied. This application screened out tomato as the optimal host plant, to conduct the differential accumulation analysis of defensive signaling substances, and to study the effect on pest population parameters and behavior. The objective of this project is to clearly study the interactions of natural enemy and host plants and the derivative effect on pest bioecology.

东亚小花蝽Orius sauteri是重要的捕食性天敌，可以取食蚜虫、粉虱、蓟马和小型鳞翅目害虫，具有巨大的生物防治功能，是目前需求量较大的优势天敌昆虫之一。但其大规模生产的技术难点仍是制约规模应用的瓶颈，主要问题来源于其将卵产入植物组织的习性。小花蝽将卵产入植物嫩叶叶柄、叶脉等处，造成繁育时基质植物替换和营养把控难度大；同时产卵孔造成植物组织损伤。植物在受到病虫害侵染及机械损伤时，产生系统防御反应，所以亟需研究东亚小花蝽产卵行为与寄主植物防御反应的相互作用关系。申请人前期研究发现，西花蓟马和烟粉虱对于小花蝽产卵的植物产生趋避行为。但引起哪些防御信号物质的积累仍有待深入研究。本申请筛选了番茄作为寄主植物，进行防御信号物质差异积累分析，并研究天敌产卵对害虫种群参数和行为的影响，以期明确天敌与寄主植物的互作关系及对害虫生物生态学的衍生作用。

东亚小花蝽是具有较强生物防治潜能的重要捕食性天敌，是目前需求量较大的优势天敌之一。其将卵产入植物嫩叶叶柄、叶脉等组织内，卵的发育和孵化与否取决于寄主植物的生理状况，造成繁育时基质植物替换和营养把控难度大，制约了工厂化生产和大规模应用。植物在受到病虫害侵染或机械损伤时，产生系统防御反应，而小花蝽的产卵孔会对植物造成微小的机械损伤，所以我们研究了东亚小花蝽产卵行为与寄主植物防御反应的相互作用关系。结果表明，东亚小花蝽雌虫在番茄上的预侵染会显著降低西花蓟马的存活率和F1代若虫数量，但雄虫的预侵染只会降低该害虫F1代的若虫数量，且显著高于雌虫处理。以上现象可能是由小花蝽产卵诱导番茄JA途径激活引起的：害虫西花蓟马、东亚小花蝽雌虫和雄虫侵染的番茄叶片显著增加了JA途径关键基因PI-1、AOS和JAZ2的相对表达量以及JA和JA-Ile的积累量，害虫处理组显著高于小花蝽处理组，雌虫和雄虫处理之间也存在显著差异。因此，雌性小花蝽的产卵行为可通过诱导番茄防御反应降低害虫西花蓟马的适合度。本研究首次提出东亚小花蝽除直接捕食害虫外，还可通过发挥类似于“免疫诱抗剂”的功能来防控西花蓟马。