Phylogenetic Analysis of Fungal Reproductive Strategies Using Mating Type Genes

选择子囊菌属Cochliobolus及其近缘属的9806935种作为本研究的重点，是因为它们具有一系列的生殖策略，适合于遗传和分子技术，以及该类群中的某些物种能够导致重要作物的毁灭性疾病。我们的目标是了解真菌繁殖策略的演变，并最终了解致病能力。结果将直接关系到真菌生物多样性的评估，与生物勘探计划中真菌的开发，以及控制真菌引起的疾病的战略的设计。真菌是这些研究的有利对象，因为它们很小，在实验室里容易驯化，而且它们的特点使它们成为生殖比较研究的理想对象。与之密切相关的真菌可以是自不育(交配需要配偶)、自育(不需要伴侣)、有性或无性。我们将使用调节性发育的基因的DNA序列，交配型(MAT)基因来探索有性和无性真菌繁殖策略的进化。MAT基因在追踪真菌种群之间的关系方面有着巨大的前景，因为它们具有优越的系统发育分辨率。我们将确定：1)无性真菌是否真的是无性的，或者如果有性状态只是未被发现，2)MAT基因是否可以用来描述物种，以及3)MAT基因系统发育，以及关于性别和物种边界的新信息，是否可以用来预测真菌致病性的未来变化，以及可能的新致病小种的进化。此外，系统发育信息将指导鉴定产生代谢产物的真菌，具有潜在的药物应用和正在进行的真菌致病分子机制的研究。

Turgeon DEB 9806935 Species of the ascomycete genus Cochliobolus and its allied genera have been chosen as the focus for this study for their array of reproductive strategies, their suitability for genetic and molecular technology, and the ability of certain species within the group to cause devastating diseases of important crops. Our goal is to understand the evolution of fungal reproductive strategies and, eventually, pathogenic capability. Results will be directly relevant to the assessment of fungal biodiversity, to the exploitation of fungi in bioprospecting programs, and to design of strategies for control of diseases caused by fungi. Fungi are favorable subjects for these studies because they are small, tractable in the laboratory, and have features which make them ideal for comparative studies of reproduction. Closely related fungi can be self sterile (requiring a partner for mating), self-fertile (no partner required), obligately sexual or obligately asexual. We will use DNA sequences for genes that regulate sexual development the mating type (MAT) genes to explore the evolution of reproductive strategies in sexual and asexual fungi. MAT genes hold great promise for tracing relationships among fungal groups because they have superior phylogenetic resolving power. We will determine: 1) If asexual fungi really are asexual or if the sexual state is just undiscovered, 2) if MAT genes can be used to delineate species, and 3) if MAT gene phylogenies, together with new information on sexuality and species boundaries, can be used to predict future changes in fungal pathogenicity, and possibly the evolution of new pathogenic races. In addition, phylogenetic information will guide identification of fungi producing metabolites with potential pharmaceutical application and ongoing investigations into the molecular mechanisms of fungal pathogenesis.