Strength in diversity: the effects of host-parasite genetic diversity on transmission and evolution

多样性的力量：宿主-寄生虫遗传多样性对传播和进化的影响

• 批准号: NE/G006849/1
• 负责人: William Hughes
• 金额: $ 60.81万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG006849%2F1
• 关键词: Strength; diversity; effects; host; parasite

Parasites are a dominant force in nature. Perhaps as many as half of all species have a parasitic lifestyle and they have powerful effects on the fitness of the organisms they infect. Many studies of host-parasite interactions have considered only the simplest scenario of a single parasite infecting a single host genotype. However, most host-parasite interactions are far more complex than this. Host populations are made up of a diversity of genotypes that will vary in their resistance to parasites. Parasite infections commonly consist of multiple strains of parasite that will vary in virulence. The interaction is not always straightforward, with, for example, parasites that are virulent in one host genotype, relative to other parasites strains, being relatively less virulent in another host genotype. When infections involve multiple parasite strains, they compete to exploit the limited resources provided by the host, with the most virulent strains being likely to win. Most models therefore predict that within-host competition between parasite strains results in an infection expressing greater virulence, and will also select over evolutionary time for parasites of greater virulence. However, experimental evidence for these effects is limited and contradictory, with some studies finding that less virulent strains in fact win during within-host competition or that the outcome is dependent on the host genotype in which the competition takes place. This project will investigate the effects of both host and parasite genetic diversity on parasite virulence, transmission and evolution, in honeybees and their fungal parasite, chalkbrood. Honeybees are an excellent model host because, unusually for a social insect, their colonies have relatively high genetic diversity. This makes the identification of genetic effects on resistance straightforward to identify and has been suggested to have evolved to improve their resistance to disease. The chalkbrood parasite is also an excellent model because it produces a single batch of characteristic spores shortly after killing its host, which makes parasite fitness easy to measure. Chalkbrood also has an intriguing reproductive biology, requiring mating between two opposite 'sex' strains to reproduce. Whereas within-host interactions between most parasites are competitive, for chalkbrood they may therefore be either competitive or mutualistic depending upon the sexes of the interacting strains. The project will combine advanced apicultural, microbiological and genetic techniques to examine how honeybee and chalkbrood genetic diversity determines the outcome of infections. It will use a powerful genetic method to quantify the actual within-host dynamics of infections involving multiple parasite strains. Finally it will carry out experimental evolution to establish how host and parasite genetic diversity impacts the evolution of the chalkbrood parasite. Recent epidemics, such as of the Varroa parasite and Colony Collapse Disorder, have highlighted the vulnerability of honeybees to disease, but honeybees suffer from a number of widespread endemic parasites, such as chalkbrood, that also significantly reduce their fitness and productivity. Honeybees are estimated to pollinate crops worth £200 million per annum in the UK, as well as many endangered plant species, so managing their populations sustainably is important for both natural ecosystems and agriculture in the UK. The threat of disease is the principle concern of UK beekeepers today. The results of the project will therefore help inform management strategies, as well as significantly advancing our understanding of the evolutionary biology of host-parasite interactions in general.

寄生虫是自然界的主要力量。也许多达一半的物种具有寄生的生活方式，它们对感染生物的适应性具有强大的影响。许多对宿主 - 寄生虫相互作用的研究仅考虑了感染单一宿主基因型的单个寄生虫的最简单情况。但是，大多数宿主 - 寄生虫相互作用远比这要复杂得多。宿主种群由多种基因型组成，这些基因型会因其对寄生虫的抵抗而异。寄生虫感染通常由多种寄生虫菌株组成，这些寄生虫会因病毒而变化。相对于其他寄生虫菌株，在一种宿主基因型中具有强毒性的寄生虫并不总是直接的，在另一种宿主基因型中相对较小。当感染涉及多种寄生虫菌株时，他们竞争探索宿主提供的有限资源，最有毒的菌株可能会获胜。因此，大多数模型预测，寄生虫菌株之间的主竞争会导致感染表达更大的病毒，并且还将选择大型病毒寄生虫的进化时间。但是，这些效果的实验证据是有限的和矛盾的，一些研究发现，实际上在主机竞争期间获胜的毒性较少，或者结果取决于竞争发生的宿主基因型。该项目将研究宿主和寄生虫遗传多样性对寄生虫病毒，传播和进化的影响，蜜蜂及其真菌寄生虫Chalkbroom。蜜蜂是一个出色的模型主机，因为在社交昆虫方面，它们的菌落具有相对较高的遗传多样性。这使得鉴定遗传对抗性的影响直接识别，并被认为已经进化以提高其对疾病的抵抗力。 Chalkbroom寄生虫也是一个极好的模型，因为它在杀死宿主后不久会产生一批特征性孢子，这使得寄生虫健身易于测量。 Chalkbroom还具有有趣的复制生物学，需要在两个相反的“性别”菌株之间交配才能繁殖。尽管大多数寄生虫之间的主机相互作用是竞争性的，但对于白垩室而言，它们可能取决于相互作用的菌株的性别。该项目将结合先进的植根品，微生物和遗传技术，以研究Honeybee和Chalkbroom遗传多样性如何决定感染的结果。它将使用强大的遗传方法来量化涉及多个寄生虫菌株的感染的实际内部动力学。最后，它将进行实验进化，以建立宿主和寄生虫遗传多样性如何影响雪植物寄生虫的演变。最近的流行病，例如Varroa寄生虫和菌落崩溃障碍，强调了蜜蜂对疾病的脆弱性，但蜜蜂遭受了许多宽度的内粒寄生虫（例如Chalkbrood）的困扰，这些寄生虫（例如chalkbrood）也大大降低了其适应性和生产力。据估计，在英国，蜜蜂每年授粉价值2亿英镑的农作物，以及许多濒临灭绝的植物物种，因此对其人口的可持续管理对英国的自然生态系统和农业都很重要。疾病的威胁是当今英国养蜂人的主要关注点。因此，该项目的结果将有助于为管理策略提供信息，并显着促进我们对总体上寄养物相互作用的进化生物学的理解。

项目成果

Nutritional stress and stonebrood susceptibility in honey bee larvae: a role for pollen in disease resistance?

蜜蜂幼虫的营养应激和石巢易感性：花粉在抗病方面的作用？

• 发表时间: 2010
• 期刊: Winter Meeting of the North-western European Section of the International Union for the Study of Social Insects
• 作者: Foley K.

Innate expression of antimicrobial peptides does not explain genotypic diversity in resistance to fungal brood parasites in the honey bee

• DOI: 10.1007/s13592-015-0388-4
• 发表时间: 2016-03-01
• 期刊: APIDOLOGIE
• 影响因子: 2.4
• 作者: Evison, Sophie E. F.;Fazio, Geraldine;Hughes, William O. H.
• 通讯作者: Hughes, William O. H.

Host-parasite genotypic interactions in the honey bee: the dynamics of diversity.

• DOI: 10.1002/ece3.599
• 发表时间: 2013-07
• 期刊: ECOLOGY AND EVOLUTION
• 影响因子: 2.6
• 作者: Evison, Sophie E. F.;Fazio, Geraldine;Chappell, Paula;Foley, Kirsten;Jensen, Annette B.;Hughes, William O. H.
• 通讯作者: Hughes, William O. H.

Strength in diversity; a genetic basis to resistance to brood diseases in honeybees

多元化的力量；

• 发表时间: 2011
• 作者: Evison SEF