Phylogenetic Analysis of Fungal Reproductive Strategies Using Mating Type Genes

选择子囊菌属Cochliobolus及其亲缘属的一种作为本研究的重点，因为它们具有一系列的繁殖策略，适合遗传和分子技术，并且该组内某些物种能够引起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进化，并最终了解致病能力。研究结果将直接关系到真菌生物多样性的评估、真菌在生物勘探计划中的开发以及真菌引起的疾病控制策略的设计。真菌是这些研究的有利对象，因为它们很小，在实验室中易于处理，并且具有使它们成为生殖比较研究的理想特征。密切相关的真菌可以是自育的（需要伴侣交配），自育的（不需要伴侣），专有性的或专无性的。我们将使用基因的DNA序列来调节交配型（MAT）基因的性发育，以探索有性和无性真菌的生殖策略的进化。MAT基因在追踪真菌类群之间的关系方面有很大的希望，因为它们具有优越的系统发育分辨力。我们将确定：1)无性真菌是否真的是无性的，还是性状态只是未被发现；2)MAT基因是否可以用来描述物种；3)MAT基因系统发育，以及关于性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，甚至可能是新的致病种族的进化。此外，系统发育信息将指导真菌产生具有潜在药物应用的代谢物的鉴定以及对真菌发病机制的分子机制的研究。

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.