Ecological consequences of plant parasitism in Euphrasia

幼发拉西亚植物寄生的生态后果

• 批准号: 1802002
• 金额: --
• 依托单位: University of Edinburgh
• 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-1802002
• 关键词: Ecological; consequences; plant; parasitism; Euphrasia

Parasitism is a ubiquitous phenomenon in the natural world, with dramatic evolutionary and ecological consequences for both the host and the parasite. There are over 3000 described parasitic plant species, including Rhinanthus, which maintains grassland ecosystems by stunting the growth of other herbaceous plants, and Striga, which decimates 12 billion dollars' worth of rice crops each year. While plant parasitism has a major effect on natural ecosystems, our understanding of the ecology of plant parasitism is surprisingly poor. In order to understand the origin and maintenance of plant parasitism, it is necessary to study the fitness benefit plant parasites receive from host attachment, and the genes associated with the parasitic plant syndrome.This project investigates the ecological consequences of parasitism in Euphrasia, a group of generalist plant parasites which can grow independently, but grow more vigorously when attached to a suitable host plant. The genus includes c. 20 species in the UK, with each species showing notable habitat preferences (e.g. coastal, montane, meadow), and thus potentially different local host preferences, too. We have recently made seed collections from populations across the UK, as well as developed new genomic resources (whole draft-genome sequences), enabling us to investigate the ecological significance and genomic basis of parasitism and host preferences.This project incorporates large-scale plant growth trials and cutting-edge gene expression data to address the following research questions:1) Do Euphrasia species adapted to different habitats (montane vs coastal) have preferences for different host species?2) What are the phenotypic and ecophysiological changes with alternative host attachment?3) Are there major gene expression changes associated with attaching to different host plants?In addition to answering these research questions, this project will also involve an industrial placement with CASE partner Scotia Seeds, the leading producer of wildflower seeds in Scotland. During a series of short placements throughout the PhD, the student will test germination protocols and procedures for growing Euphrasia as a commercial crop for wildflower seed mixes.Overall, this project represents an exciting example of where the combination of growth trials and genomic tools may give insight into questions in evolutionary biology and food security challenges.The core of this project relies on analysing fitness of plants grown with different hosts, in a large common garden experiment based at the Royal Botanic Garden Edinburgh (RBGE), and with additional trials at the Scotia Seed site. Seeds sourced from different habitats will be scored for vegetative vigour and seed set, to understand fitness when grown with a local vs. non-local host plant.Other methods used in the project will be developed in line with the students' interests. Individuals with a strong interest in genomics will be able to use laser-dissection microscopy and tissue-specific RNA sequencing to study the gene expression changes at the host-parasite interface. This will reveal gene expression changes associated with host attachment. Alternatively, or in addition, students interested in ecology will use new tools to quantify ecophysiological changes associated with host attachment. Chlorophyll fluorescence is a powerful tool which could be used to investigate how parasitism could damage the photosynthetic apparatus of the host plant, and potentially enhance the photosynthetic capacity of the parasite. A comprehensive training programme will be provided comprising both specialist scientific training and generic transferable and professional skills. The student will be taught experimental design for common garden growth studies, how to produce next-generation sequencing data, a variety of genetic analyses (related to the analysis of gene expression data), and skills related to experiments in plant evolutionary biolo

寄生是自然界中普遍存在的现象，对宿主和寄生虫都具有戏剧性的进化和生态后果。有超过3000种描述的寄生植物物种，包括Rhinanthus，它通过阻碍其他草本植物的生长来维持草原生态系统，Striga，每年摧毁价值120亿美元的水稻作物。虽然植物寄生对自然生态系统有重大影响，但我们对植物寄生生态学的理解却令人惊讶地贫乏。为了了解植物寄生的起源和维持，有必要研究植物寄生虫从寄主附着中获得的适合度益处，以及与寄生植物综合征相关的基因。该属包括C。英国有20种，每种都显示出明显的栖息地偏好（例如沿海，山地，草甸），因此也可能有不同的当地宿主偏好。我们最近从英国各地的种群中收集了种子，并开发了新的基因组资源。（全基因组草图序列），使我们能够研究寄生和寄主偏好的生态学意义和基因组基础。该项目结合了大规模植物生长试验和尖端基因表达数据，以解决以下研究问题：1）适应不同生境（山地与沿海）的大戟属物种是否对不同的寄主物种有偏好？2)寄主选择性附着的表型和生理生态变化是什么？3)是否有主要的基因表达变化与附着到不同的宿主植物？除了回答这些研究问题，该项目还将涉及与CASE合作伙伴斯科舍种子，在苏格兰领先的野花种子生产商的工业布局。在整个博士学位的一系列短期实习中，学生将测试将Euphrasia作为野花种子混合物的商业作物种植的发芽协议和程序。该项目代表了一个令人兴奋的例子，即生长试验和基因组工具的结合可能会洞察进化生物学和粮食安全挑战中的问题。该项目的核心依赖于分析植物的适应性，在爱丁堡皇家植物园（RBGE）的大型普通花园实验中，以及在斯科舍种子点的附加试验中，来自不同生境的种子将根据植物活力和结实率进行评分，以了解与本地和非本地宿主植物生长的适应性。项目中使用的其他方法将根据学生的兴趣开发。对基因组学有浓厚兴趣的人将能够使用激光解剖显微镜和组织特异性RNA测序来研究宿主-寄生虫界面的基因表达变化。这将揭示与宿主附着相关的基因表达变化。或者，或此外，对生态学感兴趣的学生将使用新的工具来量化与主机连接相关的生态生理变化。叶绿素荧光是研究寄生虫如何破坏寄主植物光合机构、增强其光合能力的有力工具。将提供一个全面的培训方案，其中包括专业科学培训和通用的可转让的专业技能。学生将学习常见花园生长研究的实验设计，如何产生下一代测序数据，各种遗传分析（与基因表达数据分析相关），以及与植物进化生物学实验相关的技能。