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

克赖特曼9800957植物品种通常表现出抗病能力的变异。这一惊人的观察表明，对立力量的平衡有助于保持抗病能力的变异。由于疾病造成的成本将促使人口增加抗药性，因此，为了考虑到观察到的变化，应该进行权衡，反对增加抗药性。在模式植物拟南芥中，对立力量的平衡维持了抗病基因Rpm1的分子变异。这项拟议的研究将调查种群内抗病能力变异的来源和决定因素。高通量方法将允许从印第安纳州和密歇根州的当地人口中对数百个柳杉个体进行基因分型。分析将衡量Rpm1与附近遗传标记之间的关联。很少的关联将支持人口内部的平衡，而更大的关联将支持由于不同力量占主导地位的人口之间的迁移而实现的平衡。拟南芥的抗病能力最近受到了广泛的研究，这里提出的生态和进化工作将补充这一系统的分子遗传学工作。必须了解植物抗病能力，以促进作物病害的管理，评估种植策略，并预测疾病对自然植物种群和杂草的影响。此外，可以将植物的抗病能力与动物的免疫力进行比较，以便更全面地了解病原体对寄主物种施加的压力。这个项目继续着Kreitman对果蝇的研究，在种群遗传学理论和经验数据之间的交界处。拟南芥Rpm1是平衡选择、维持分子变异的有力例子。对Rpm1的继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，拟议的工作将继续把拟南芥发展成为一种重要的新的群体遗传学模式生物。可以说，没有其他模式生物在与生态学和遗传学的相互作用方面提供了如此大的潜力，这两个领域都是拟南芥生物学中公认的领域。

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.