Dissertation Research: The Importance of Mixed Reproductive Strategies on Plant/Pathogen Interactions

9520662黏土寄生虫可能是许多物种维持遗传多样性和繁殖的重要进化因素。植物可以自花授粉，也可以与另一株植物异交。后者比自花受精产生更大的遗传变异。尽管许多植物可以同时使用这两种机制，但混合系统在哪些条件下具有优势还不是很清楚。丹参是一种能够通过异交和自花繁殖的草。当感染阿金森氏菌时，异交花的发育被阻止，并在其所在的地方形成了带有感染孢子的真菌结构。这种真菌还可以通过感染通过自交产生的种子来传播。这种防止异交的寄生策略已经在其他系统中观察到，这可能有利于寄生虫降低寄主植物的遗传变异性，或者因为有更多的植物资源可用于真菌繁殖。这个项目将调查真菌A.subxylon是否在维持寄主D.spicata的混合生殖系统方面起作用，以及寄主的生殖系统如何影响寄生虫的成功。每种真菌传播方式(传染传播或感染寄主种子)的优势令人感兴趣，因为每种传播方式都与不同程度的寄生虫对宿主的影响有关，并可能导致不同的疾病传播模式。在病原体存在的情况下，通过自交和异交寄主成功的比较将有助于阐明保持植物遗传多样性的重要性。这些信息对于制定保护政策，将濒危物种的疾病损害降至最低是重要的。这也将对开发更好的农业实践以减轻病原菌对作物的损害具有潜在价值。

9520662 CLAY Parasites may be important evolutionary agents for the maintenance of genetic diversity and reproduction in many species. Plants can either self-fertilize or outcross with another plant. The latter produces greater genetic variability than self-fertilization. Although many plants can use both mechanisms, the conditions in which mixed systems are advantageous are not well understood. Danthonia spicata is a grass that can reproduce through outcrossing and selfing flowers. When infected with the fungus Atkinsonella hypoxylon, the development of outcrossing flowers is prevented and a fungal structure that bears infective spores develops in its place. The fungus can also spread by infecting the seeds produced through selfing. This parasite strategy of preventing outcrossing has been observed in other systems and might be advantageous for the parasite to reduce genetic variability of host plants or because more plant resources are available for fungal reproduction. This project will investigate whether the fungus A. hypoxylon acts to maintain the mixed reproductive system in the host D. spicata, and how the host's reproductive system affects the success of the parasite. The advantage of each fungal transmission mode (contagious spread or infection of host seeds) is of interest because each mode is associated with different levels of parasite effect on the host and can lead to different disease spread patterns. Comparison of the host success through selfing and outcrossing in the presence of pathogens will shed light on the importance of maintaining genetic diversity in plants. This information is important for constructing conservation policies for minimizing disease damage in endangered species. It will also be of potential value for developing better agricultural practices to alleviate pathogen damage to crops.