Mechanisms of host plant induced plasticity of cuticular hydrocarbon phenotypes in mustard leaf beetles

寄主植物诱导芥菜叶甲表皮碳氢化合物表型可塑性的机制

• 批准号: 392668240
• 负责人: Dr. Sven Geiselhardt
• 金额: --
• 依托单位: Institut für Biologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/392668240?language=en
• 关键词: Mechanisms; host; plant; induced; plasticity

Cuticular hydrocarbons (CHCs) play an essential role in species and mate recognition in insects. Among other biotic and abiotic factors, diet could affect the CHC phenotype of an insect and these changes may modify the mating behavior and lead to reproductive isolation between populations or closely related species with divergent host use. The two oligophagous mustard leaf beetle species Phaedon armoraciae and Phaedon cochleariae co-occur in the same habitat, but differ in host use. Under natural conditions (different host species), both species show behavioral isolation. However, if both species were reared on the same host plant species, behavioral isolation breaks down and both species mate randomly. Chemical analyses show that the CHC phenotype is strongly affected by host use. CHC phenotypes of beetles reared on the same host species are more similar than CHC phenotypes of beetles reared on different host species, irrespective of population or species identity of the beetles. Diet could have a significant effect on the gut microbiome. These changes in the gut microbiome could change the CHC phenotype as well as the mating behaviour. The aims of this research project are (A) to investigate whether host-specific assortative mating is adaptive in terms of performance and immunocompetence of the offspring, and (B) to elucidate the mechanisms behind the diet-inducted plasticity of CHC phenotypes in mustard beetles and the potential role of the gut microbiome. In a first step, we will rear both beetle species on different host plant species to illustrate the impact of divergent host use on the gut microbiome. In order to identify the plant-associated trigger for the change in CHC phenotypes, we will rear beetles (i) on a single host species of which we will manipulate the phyllosphere microbiomes differently, and (ii) on different artificial diets that differ in the supplementation with host-specific secondary metabolites. In a next step, we will follow the change of the gut microbiome after a host shift to associate the temporal change of the gut microbiome with the change in the CHC phenotype. Furthermore, we will use an RNA-seq approach to analyse the impact of divergent host use and gut microbiomes, respectively, on gene expression in beetles with a special focus on oenocytes, the site of CHC biosynthesis. Subsequently, the role of selected candidate genes in host-triggered plasticity of CHC phenotypes will be validated by RNA interference (RNAi). The results of our project will provide new fundamental knowledge about the regulatory mechanisms of the CHC biosynthesis and highlight the role of interspecific interactions and phenotypic plasticity in the divergence of communication systems in insects.

表皮碳氢化合物在昆虫的物种识别和配偶识别中起着重要的作用。在其他生物和非生物因素中，饮食可以影响昆虫的CHC表型，这些变化可能会改变交配行为，并导致种群或具有不同宿主用途的密切相关物种之间的生殖隔离。两种寡食性芥菜叶甲种-在自然条件下（不同的宿主物种），这两个物种表现出行为隔离。然而，如果这两个物种在同一宿主植物物种上饲养，行为隔离就会打破，两个物种就会随机交配。化学分析表明，CHC的表型受到宿主使用的强烈影响。无论甲虫的种群或物种身份如何，在相同宿主物种上饲养的甲虫的CHC表型比在不同宿主物种上饲养的甲虫的CHC表型更相似。饮食可能对肠道微生物组产生显着影响。肠道微生物组的这些变化可能会改变CHC表型以及交配行为。本研究项目的目的是（A）调查宿主特异性交配是否在后代的性能和免疫能力方面具有适应性，以及（B）阐明芥子甲虫中CHC表型的饮食诱导可塑性背后的机制以及肠道微生物组的潜在作用。在第一步中，我们将在不同的宿主植物物种上饲养这两种甲虫物种，以说明不同的宿主使用对肠道微生物组的影响。为了确定CHC表型变化的植物相关触发因素，我们将饲养甲虫（i）在单一宿主物种上，我们将以不同的方式操纵叶际微生物组，以及（ii）在不同的人工饲料中补充宿主特异性次级代谢产物。在下一步中，我们将跟踪宿主转移后肠道微生物组的变化，以将肠道微生物组的时间变化与CHC表型的变化相关联。此外，我们将使用RNA-seq方法来分析不同宿主使用和肠道微生物组分别对甲虫基因表达的影响，特别关注CHC生物合成的位点-卵母细胞。随后，将通过RNA干扰（RNAi）验证所选候选基因在宿主触发的CHC表型可塑性中的作用。我们的项目的结果将提供有关CHC生物合成的调控机制的新的基础知识，并强调种间相互作用和表型可塑性在昆虫通讯系统的分歧中的作用。