Genetic and environmental effects on virulence of European foulbrood, a bacterial pathogen of honey bees

遗传和环境对欧洲幼虫腐臭病（蜜蜂细菌病原体）毒力的影响

• 批准号: 1792230
• 金额: --
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1792230
• 关键词: Genetic; environmental; effects; virulence; European

Honey bees (Genus Apis) are economically important pollinators of crops as well as producers of honey. They are under significant threats from emerging diseases and changes in management practices that adversely affect their feeding environment. In the UK, one of the most damaging diseases, treatable only by hive destruction, is American Foulbrood (AFB). A previous York-Fera BBSRC CASE studentship project developed a Multi-Locus Sequence Typing (MLST) scheme for Paenibacillus larvae, the causative agent of American Foulbrood. Outbreaks have, since 2014, been routinely typed, and we seek to build on this work to determine the extent to which this information can be used to predict occurrence and spread of AFB.Left untreated, AFB will kill a colony of bees. Spores are fed to larvae, where they germinate in the gut, and, after the hive cell is "capped", the bacteria proliferate, eventually killing the larva and forming millions of resistant spores that are later dispersed. There are many genotypes present in the UK, and they show high levels of strain variation, defined both by the MLST and comparative genomics. Recent research shows that community diversity and competition processes in the gut microbiome encountered by pathogens is important in determining the progress and outcome of infections. The gut microbiome in turn, is determined by external environmental factors, such as food resources. We therefore hypothesise that the outcome of AFB infection in a hive is a complex interaction between disease strain genotype and the larval gut environment it encounters.The overarching aim of this project is to link genotypes within and among Clonal Complexes (CC) that have been defined by the MLST, with disease symptoms and the environment in which they occur, and to translate this into an inspection and monitoring scheme that will further contribute to keeping this destructive disease under control.The studentship will address four research areas:1) Population Genetics: Building on previous analysis (Morrissey et al. 2015; see below), and using data collected subsequently using the MLST, what is the spatial and temporal pattern of AFB outbreaks? Can Clonal complexes (CCs) be used reliably to discriminate new outbreaks from re-infections?2) Comparative Genomics: isolates collected from CCs with known distribution and disease severity, genome sequence will be determined and extensive analysis of genes related to virulence analysed.3) Environmental Genomics: what environmental factors influence the patterns of disease prevalence and severity? The student will investigate bee host gut microbiomes, and their relationship to infection by particular types of AFB.4) Practical applications: There are a number of ways in which the studies may influence screening and management of AFB. If MLST type predicts disease severity, then outbreaks can be prioritized for destruction, and follow up inspection regimes recommended. More complex environmental factors such as food resources and gut microbiomes may predict which strains successfully infect the hive, or the severity of the disease once infection becomes established. The most promising route to practical mitigation of disease will be identified and developed by the student.The project will combine genomics techniques and analysis at the University of York, with the opportunity to carry out experiments at Fera, in collaboration with the Bee Unit, and their state of the art facilities for culturing and manipulating AFB.

蜜蜂（蜜蜂属）是经济上重要的农作物传粉者以及蜂蜜生产者。它们受到新出现的疾病和管理实践变化的严重威胁，这些变化对它们的饲养环境产生了不利影响。在英国，美洲臭虫病 (AFB) 是最具破坏性的疾病之一，只能通过破坏蜂巢来治疗。之前的约克-费拉 BBSRC CASE 学生项目针对美国臭虫病的病原体类芽孢杆菌幼虫开发了多位点序列分型 (MLST) 方案。自 2014 年以来，我们对疫情进行了常规分类，我们力求在这项工作的基础上确定这些信息可在多大程度上用于预测 AFB 的发生和传播。如果不加以治疗，AFB 将杀死一群蜜蜂。孢子被喂给幼虫，它们在肠道中发芽，在蜂巢细胞被“封顶”后，细菌就会增殖，最终杀死幼虫并形成数百万个耐药孢子，这些孢子随后被分散。英国存在许多基因型，并且它们表现出高水平的菌株变异，这是由 MLST 和比较基因组学定义的。最近的研究表明，病原体遇到的肠道微生物组的群落多样性和竞争过程对于确定感染的进展和结果很重要。肠道微生物群又由外部环境因素（例如食物资源）决定。因此，我们假设蜂巢中 AFB 感染的结果是疾病菌株基因型与其所遇到的幼虫肠道环境之间的复杂相互作用。该项目的总体目标是将 MLST 定义的克隆复合体 (CC) 内部和之间的基因型与疾病症状及其发生的环境联系起来，并将其转化为检查和监测方案，这将进一步有助于保持这种破坏性 该奖学金将涉及四个研究领域：1) 群体遗传学：基于之前的分析（Morrissey 等人，2015 年；见下文），并使用随后使用 MLST 收集的数据，AFB 爆发的空间和时间模式是什么？克隆复合物 (CC) 能否可靠地用于区分新的疫情和再次感染？2) 比较基因组学：从已知分布和疾病严重程度的 CC 中收集的分离株，将确定基因组序列，并对与毒力相关的基因进行广泛分析。3) 环境基因组学：哪些环境因素影响疾病流行和严重程度的模式？学生将研究蜜蜂宿主肠道微生物群及其与特定类型 AFB 感染的关系。4) 实际应用：研究可能通过多种方式影响 AFB 的筛查和管理。如果 MLST 类型预测疾病严重程度，则可以优先销毁疫情，并建议采取后续检查制度。更复杂的环境因素，例如食物资源和肠道微生物组，可以预测哪些菌株成功感染蜂巢，或者一旦感染建立，疾病的严重程度。学生将确定和开发最有希望的实际缓解疾病的途径。该项目将结合约克大学的基因组学技术和分析，并有机会与蜜蜂单位及其最先进的 AFB 培养和操作设施合作，在费拉进行实验。