Impact of plant-beneficial soil microbes on aboveground parasitism of insect herbivores

对植物有益的土壤微生物对食草昆虫地上寄生的影响

• 批准号: NE/X012433/1
• 负责人: Angharad Gatehouse
• 金额: $ 1.25万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX012433%2F1
• 关键词: Impact; plant; beneficial; soil; microbes

Aphids are important plant sap-feeding insects, affecting plant ecology and crop yields by direct feeding and transmission of plant viruses. These small soft-bodied insects are well-known pests of agricultural crops, as well as ornamental plants such as roses and tulips. Populations of aphids are naturally controlled by (i) host plant resistance and (ii) aphid natural enemies (including ladybirds, lacewings, syrphids, and parasitoid wasps). With a deeper understanding of how plants deal with herbivores in natural populations, we can exploit these beneficial interactions and implement sustainable pest control methods. Under current climate predictions, insect pest outbreaks are likely to increase with consequences for reduced crop yields and future impacts on the natural environment through increased conversion of land for agriculture or increased application of pesticides.We have shown that host plant 'anti-aphid' defences can be induced by inoculating barley plant roots with naturally occurring beneficial bacteria, which reduces aphid reproduction and lifespan, and thus population sizes. We recently discovered that aphids on microbe-inoculated plants are parasitized more and earlier by parasitoid wasps. Parasitoid wasps lay an egg inside the aphid host and, after egg-hatching, the larva feeds on the aphid before emerging as an adult leaving only a dry husk of the aphid body behind (an 'aphid mummy'). We hypothesise that plant inoculation with defence-inducing bacteria increases the attractiveness of plants to parasitoid wasps (via plant volatile chemicals), and that aphids feeding on inoculated plants are more susceptible to parasitism (reduced immune responses). Aphids also host a variety of bacterial endosymbionts that help aphids to feed on nutritionally poor plant sap, but they can also confer resistance to parasitoid wasps. We will use a set of behavioural studies combined with chemical analysis of the plant and aphid to understand how plant inoculation with beneficial bacteria can lead to increased parasitism of aphids.This work will contribute to our understanding of how plant root microbiomes can have strong impacts on aboveground interactions, and across multiple trophic levels (from soil bacteria to parasitoid wasps of herbivorous insects). Our results will improve understanding of aphid parasitism and herbivore regulation in both (i) natural ecosystems, and (ii) agroecosystems, enabling the development of sustainable insect pest management strategies.

蚜虫是重要的植物汁液昆虫，通过直接取食和传播植物病毒影响植物生态和作物产量。这些小型软体昆虫是众所周知的农作物害虫，也是玫瑰和郁金香等观赏植物的害虫。蚜虫种群自然受到 (i) 寄主植物抗性和 (ii) 蚜虫天敌（包括瓢虫、草蛉、蚜虫和寄生蜂）的控制。通过更深入地了解植物如何应对自然种群中的食草动物，我们可以利用这些有益的相互作用并实施可持续的害虫防治方法。根据目前的气候预测，虫害爆发可能会增加，从而导致农作物产量下降，并通过增加农业用地转化或增加农药的使用对未来的自然环境造成影响。我们已经表明，寄主植物的“抗蚜虫”防御能力可以通过用天然存在的有益细菌接种大麦植物根部来诱导，从而减少蚜虫的繁殖和寿命，从而减少种群规模。我们最近发现，接种微生物的植物上的蚜虫被寄生蜂寄生得更多、更早。寄生蜂在蚜虫宿主体内产卵，卵孵化后，幼虫以蚜虫为食，然后成为成虫，只留下蚜虫身体的干燥外壳（“蚜虫木乃伊”）。我们假设植物接种防御诱导细菌会增加植物对寄生黄蜂的吸引力（通过植物挥发性化学物质），而以接种植物为食的蚜虫更容易受到寄生的影响（免疫反应降低）。蚜虫还寄生着多种细菌内共生体，帮助蚜虫以营养不良的植物汁液为食，但它们也可以赋予对寄生黄蜂的抵抗力。我们将使用一系列行为研究结合植物和蚜虫的化学分析来了解植物接种有益细菌如何导致蚜虫寄生增加。这项工作将有助于我们了解植物根部微生物组如何对蚜虫产生强烈影响地上相互作用，以及跨多个营养级别（从土壤细菌到食草昆虫的寄生黄蜂）。我们的研究结果将提高对（i）自然生态系统和（ii）农业生态系统中蚜虫寄生和食草动物调节的了解，从而促进可持续害虫管理策略的制定。