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Aphids, Bacteria and Fungal Pathogens; the Ecology of a Complex Symbiosis

蚜虫、细菌和真菌病原体；

基本信息

批准号：
NE/K004972/1
负责人：
Hugh Charles Jonathan Godfray
金额：
$ 71.16万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK004972%2F1
关键词：
Aphids Bacteria Fungal Pathogens Ecology

项目摘要

The easy availability of molecular techniques over the last two decades has revolutionised our understanding of how animals and plants interact with micro-organisms. Many previously unsuspected symbioses have been discovered and many new issues for our understanding of biodiversity and community ecology have arisen. This proposal is part of a long-term project to understand the dynamics and persistence of a complex mutualistic symbiosis involving an aphid and no less than eight bacterial partners. This has become a model system used by laboratories around the world exploring the ecology and evolution of symbiosis.Aphids are familiar insects in temperate regions and in these areas are the most important pests of arable crops. Despite being closely studied since the dawn of the scientific age the last 15 years have seen a complete reappraisal of many aspects of their biology as the importance of their bacterial symbionts has become apparent. Aphids feed on plant sap which is nutritionally imbalanced and it has been known for 50 years that they carry an obligate (or primary) bacterial symbiont called Buchnera which synthesises essential nutrients missing in their diet. But we now know that in addition to Buchnera there are at least seven other facultative or secondary symbionts, present in some aphids but not others. Moreover, these facultative symbionts have many effects on their host's biology including conferring resistance to parasites and pathogens, enabling their hosts to withstand heat shock or use different host plants, and influencing life history strategy.Our laboratory has particularly worked on how symbionts influence the aphid's ability to withstand attack by fungal pathogens. We discovered that one bacteria called Regiella insecticola markedly increased resistance to the most common fungal disease. Curiously this symbiont species is particularly associated with aphids feeding on clover (pea aphid has a complex population structure comprised of genetically differentiated "biotypes" associated with different host plants within the pea family). Very recently our laboratory has mapped the genetic structure of Regiella showing that isolates from pea aphid are organised into two major genetic groups (or clades). We have also found that other recently discovered secondary symbionts can impart fungal resistance which suggests that this might be a general strategy that symbionts use to spread through host populations.The proposal is to support continuing work on pea aphid symbionts in our laboratory focussing on the ecology of the interaction between pea aphid, their host plants and fungal pathogens, and the facultative symbionts that confer resistance. We shall test the hypothesis that the aphid biotype on clover suffers particularly from fungal pathogens and hence needs to carry Regiella. Using reciprocal introductions of bacteria we shall ask why Regiella from the two major clades infect different biotypes and explore whether all clades provide resistance. Fungus can still kill aphids carrying Regiella (though with lower probability) but they are then less likely to produce infectious spores and we shall test the hypothesis that this has evolved through kin selection. All work to date has involved a single fungal pathogen though we know from our community studies that other pathogens are present in the field. We shall investigate the specificity of fungal resistance. We shall build on our recent pilot study demonstrating that some isolates of other symbionts confer resistance to establish the extent to which this occurs in natural populations. Finally, we shall use modern DNA sequencing techniques to test the hypothesis that fungal resistance is caused by a common mechanism that has been transferred horizontally amongst these unrelated bacteria.

过去二十年，分子技术的便捷应用彻底改变了我们对动植物如何与微生物相互作用的理解。许多以前未曾预料到的共生关系已经被发现，并且出现了许多我们理解生物多样性和群落生态学的新问题。该提案是一个长期项目的一部分，旨在了解涉及蚜虫和至少八个细菌伙伴的复杂互利共生的动态和持久性。这已成为世界各地实验室探索共生生态和进化的模型系统。蚜虫是温带地区常见的昆虫，是这些地区耕作作物最重要的害虫。尽管自科学时代伊始就对其进行了密切研究，但随着细菌共生体的重要性日益凸显，过去 15 年人们对其生物学的许多方面进行了彻底的重新评估。蚜虫以营养不平衡的植物汁液为食，50 年来人们就知道它们携带一种称为 Buchnera 的专性（或初级）细菌共生体，可以合成其饮食中缺少的必需营养素。但我们现在知道，除了 Buchnera 之外，至少还有七种其他兼性或次生共生体存在于某些蚜虫中，但其他蚜虫中则没有。此外，这些兼性共生体对其宿主的生物学具有许多影响，包括赋予其对寄生虫和病原体的抵抗力，使宿主能够承受热休克或使用不同的寄主植物，以及影响生活史策略。我们的实验室特别致力于研究共生体如何影响蚜虫抵御真菌病原体攻击的能力。我们发现一种名为昆虫雷吉氏菌的细菌显着增强了对最常见真菌疾病的抵抗力。奇怪的是，这种共生物种与以三叶草为食的蚜虫特别相关（豌豆蚜具有复杂的种群结构，由与豌豆科内不同寄主植物相关的遗传分化的“生物型”组成）。最近，我们的实验室绘制了 Regiella 的遗传结构图，显示豌豆蚜的分离株分为两个主要遗传群体（或进化枝）。我们还发现，其他最近发现的次生共生体可以赋予真菌抗性，这表明这可能是共生体在宿主群体中传播的一般策略。该提案是支持我们实验室对豌豆蚜共生体的持续研究，重点关注豌豆蚜、其寄主植物和真菌病原体之间相互作用的生态学，以及赋予抗性的兼性共生体。我们将检验这样的假设：三叶草上的蚜虫生物型特别容易遭受真菌病原体的侵害，因此需要携带 Regiella。通过细菌的相互引入，我们将询问为什么来自两个主要分支的Regiella感染不同的生物型，并探索是否所有分支都提供抗性。真菌仍然可以杀死携带 Regiella 的蚜虫（尽管概率较低），但它们不太可能产生传染性孢子，我们将检验这一假设，即这是通过亲缘选择进化而来的。迄今为止的所有工作都涉及单一真菌病原体，尽管我们从社区研究中知道该领域还存在其他病原体。我们将研究真菌抗性的特异性。我们将在最近的试点研究的基础上，证明其他共生体的一些分离株会产生抵抗力，以确定这种情况在自然群体中发生的程度。最后，我们将使用现代 DNA 测序技术来检验以下假设：真菌耐药性是由在这些不相关细菌之间水平转移的共同机制引起的。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Intrinsic pre-zygotic reproductive isolation of distantly related pea aphid host races.

远缘豌豆蚜宿主种族的内在合子前生殖隔离。

DOI：
10.1098/rsbl.2018.0332
发表时间：
2018
期刊：
Biology letters
影响因子：
3.3
作者：
Fazalova V
通讯作者：
Fazalova V

Horizontally transmitted symbionts and host colonization of ecological niches.

水平传播的共生体和生态壁ches的宿主定植。

DOI：
10.1016/j.cub.2013.07.029
发表时间：
2013-09-09
期刊：
CURRENT BIOLOGY
影响因子：
9.2
作者：
Henry, Lee M.;Peccoud, Jean;Simon, Jean-Christophe;Hadfield, Jarrod D.;Maiden, Martin J. C.;Ferrari, Julia;Godfray, H. Charles J.
通讯作者：
Godfray, H. Charles J.

Symbionts modify interactions between insects and natural enemies in the field.