DISSERTATION RESEARCH: Genetic Effects of Plant Defense on Above- and Below-ground Ecological Interactions and Natural Selection

论文研究：植物防御对地上和地下生态相互作用和自然选择的遗传效应

• 批准号: 1701790
• 负责人: Thomas Mitchell-Olds
• 金额: $ 2.06万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1701790&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Genetic; Effects; Plant

Using a plant species native to the Rocky Mountains in the mustard family, Boechera stricta, the investigators will test how differences in mechanisms of natural selection across environments influences the maintenance of variation of natural plant chemical defenses. In natural populations, the persistence of variation of traits among individuals allows for adaptation to occur. Despite the central role of variation in the process of adaptation, it is poorly understood how and why variation persists in the face of natural selection eliminating less fit varieties. Chemical defense strategies (various types and concentrations of mustard oils) are highly variable across natural populations of the study species. These defensive compounds have known ecological effects, both as deterrents of insect feeding on leaves (above-ground effects) and as drivers of microbial community composition in the soil (below-ground effects). The researchers will test how plant growth and reproduction are influenced by the above- and below-ground effects of different chemical defense strategies on plant-insect and plant-microbe interactions. The project provides opportunity for undergraduate training. Planned outreach activities will target middle and high school students, and also the general public during the Crested Butte Wildflower Festival.The pleiotropic effects of plant defensive chemicals and the genes that underlie them are well documented. In addition to influencing fitness by mediating herbivory in aboveground environments, defensive chemicals can affect microbial communities in the soil immediately surrounding root tissue. It is likely that interactions between above- and belowground selective pressures influence overall patterns of natural selection on plant chemistry. The investigators will test for pleiotropic above- and belowground effects of a chemical defense gene utilizing near-isogenic lines of the ecological model species, Boechera stricta (Brassicaceae), that vary in a gene controlling mustard oil biosynthesis to. They will first characterize the effects of defensive chemical profiles on microbial community assembly in the rhizosphere. Second, they will assess how rhizosphere selection affects plant fitness. Finally, they will test how the belowground context may modify aboveground effects of mustard oils as anti-herbivore defenses, and how interactions between the above- and belowground fitness effects of mustard oils result in the maintenance of genetic and trait diversity over space and time.

利用原产于落基山脉的芥菜科植物Boechera stricta，研究人员将测试不同环境中自然选择机制的差异如何影响天然植物化学防御的变化。在自然种群中，个体之间性状变异的持续存在允许适应发生。尽管变异在适应过程中发挥着核心作用，但人们对变异如何以及为何在自然选择淘汰不太适合的品种的情况下持续存在却知之甚少。化学防御策略（各种类型和浓度的芥子油）在研究物种的自然种群中变化很大。这些防御性化合物具有已知的生态效应，既可以阻止昆虫取食树叶（地上效应），也可以驱动土壤中的微生物群落组成（地下效应）。研究人员将测试植物生长和繁殖如何受到不同化学防御策略对植物-昆虫和植物-微生物相互作用的地上和地下影响。该项目为本科生培训提供了机会。 计划中的外展活动将针对初中和高中学生，以及在冠山野花节期间的公众。植物防御化学物质的多效性及其背后的基因有很好的记录。除了通过调节地上环境中的植食性来影响适合度外，防御性化学物质还可以影响根组织周围土壤中的微生物群落。地上和地下选择压力之间的相互作用可能会影响植物化学自然选择的总体模式。 研究人员将利用生态模式物种Boechera stricta（油菜科）的近等基因系来测试化学防御基因的多效性地上和地下效应，这些基因在控制芥子油生物合成的基因中有所不同。他们将首先描述防御性化学物质对根际微生物群落组装的影响。其次，他们将评估根际选择如何影响植物适合度。最后，他们将测试地下环境如何修改芥末油作为抗草食动物防御的地上效应，以及芥末油的地上和地下健身效应之间的相互作用如何导致遗传和性状多样性在空间和时间上的维持。