Dissertation Research: Mechanisms Maintaining Variation for Disease Resistance at Rpm1 in Arabidopsis thaliana

Kreitman 9800957 植物物种通常表现出抗病性的变异。 这一惊人的观察结果意味着，相反力量的平衡起到了维持抗病性变异的作用。 由于疾病带来的成本会驱使人们增加抵抗力， 应该反对增加的阻力来解释观察到的变化。在模式植物拟南芥（Arabidopsis thaliana）中，相反力量的平衡维持抗病基因Rpm 1的分子变异。 拟议的研究将调查种群内抗病性变异的起源和决定因素。 高通量方法将允许对数百个A.来自印第安纳州和密歇根州当地种群的拟南芥个体。 分析将测量Rpm1和附近遗传标记之间的关联。 小的关联将支持种群内部的平衡，而更大的关联将支持由于不同力量占主导地位的种群之间的迁移而导致的平衡。 拟南芥的抗病性是近年来研究的热点之一，本文提出的生态学和进化研究将对该系统的分子遗传学研究起到补充作用。 必须了解植物抗病性，以促进作物病害的管理，评估种植策略和预测疾病对自然植物种群和杂草的影响。 此外，植物抗病性可以与动物免疫力进行比较，以便更全面地了解病原体对宿主物种的压力。 这个项目继续在静脉Kreitman的工作果蝇，在人口遗传理论和经验数据之间的接口。 拟南芥Rpm1是一个强有力的例子，平衡选择保持分子变异。对Rpm 1的持续研究将有助于阐明形成遗传变异和变化的模式和过程。 最后，建议的工作继续进行 将拟南芥培育成为重要的群体遗传学新模式生物。 可以说，没有其他模式生物提供了与生态学和遗传学的相互作用，这两个在拟南芥生物学领域建立良好的潜力。

Kreitman 9800957 Plant species generally exhibit variation for resistance to disease. This striking observation implies that a balance of opposing forces acts to maintain variation for disease resistance. Since the cost imposed by disease would drive populations toward increased resistance, a trade-off should oppose increased resistance to account for the observed variation. In the model plant species Arabidopsis thaliana, a balance of opposing forces maintains molecular variation at disease resistance gene Rpm1. The proposed research will investigate the origin and determinants of variation for disease resistance within populations. High through-put methods will allow genotyping of hundreds of A. thaliana individuals from local populations in Indiana and Michigan. Analyses will measure associations between Rpm1 and nearby genetic markers. Little association would support a balance within populations, while greater association would support a balance due to migration among populations where different forces dominate. Arabidopsis disease resistance has come under intense study recently, and the ecological and evolutionary work proposed here will complement molecular genetic work on this system. Plant disease resistance must be understood to facilitate the management of disease in crops, for assessing planting strategies and predicting the impact of disease in natural plant populations and weeds. Furthermore, plant disease resistance can be compared with the animal immunity for a more general understanding of the pressures pathogens place on host species. This project continues in the vein of Kreitman's work on the fruit fly Drosophila, at the interface between population genetic theory and empirical data. Arabidopsis Rpm1 is a strong example of balancing selection maintaining molecular variation. Continuing study of Rpm1 will help elucidate the patterns and processes shaping genetic variation and change. Finally, the proposed work continues to develop Arabidopsis as an important new model organism for population genetics. Arguably, no other model organism affords as much potential for interplay with ecology and genetics, both well-established fields in Arabidopsis biology.