COLLABORATIVE RESEARCH: Relationships Among Gene Lineages, Morphology, Geography and Fungal Associations in Corallorhizinae (Orchidaceae)

[04:15 . 92]兰花是最大的开花植物家族，种类繁多。至少在种子发芽时，它们都寄生在真菌上，但人们对这种关系知之甚少。有些兰花依靠真菌获取所有营养，因为它们不进行光合作用。珊瑚兰属的兰花是最好的例子，主要包括11种北美温带山地陆生植物。这个群体提供了一个特殊的机会来研究当植物放弃光合作用时发生的变化，因为至少有一种物种是光合作用的，而其他物种不是。这些变化包括叶绿体DNA的部分丢失，植物的结构修饰，以及在其相关真菌群之间的转移。通过DNA序列分析重建珊瑚科植物及其真菌种群之间的系统发育关系，将揭示兰花与真菌的关联在多大程度上是随机的，而不是针对某些真菌群体；加上兰花的形态和地点数据将显示真菌利用的变化是否与这些因素有关。由于密集的采样，任何现代分布与谱系历史的重复相关性都将被显示出来，这可能反映了冰川后的迁移。这将使我们更好地了解目前北美植物分布的形成过程。该项目结合了精心策划的实地调查，以获得兰花和真菌样本，并汇集了俄亥俄州立大学兰花专家约翰·弗罗伊登斯坦和阿拉斯加大学真菌专家唐纳德·泰勒的专业知识，以促进全面的分析，否则是不可能的，产生可能是迄今为止最详细和多方面的植物-微生物相互作用分析。这个项目在许多方面对科学和其他领域产生了广泛的影响。它提供了一个综合的现代方法来详细分析开花植物-真菌关联，植物形态，基因谱系和地理。因此，它可以作为将来在类似系统上工作的模型。它通过将这些分类群的新藏品带入博物馆，使它们具有广泛的可访问性，并将DNA序列生成到公共数据库中，以便所有人都可以使用，从而增强了科学的基础设施。与中国、韩国和墨西哥科学家的互动将加强合作网络。该项目通过将研究生和本科生纳入项目，将研究和教育结合在一起。通过将该项目的成果作为项目负责人在系统学、微生物多样性和共生等课程的教学以及向公众推广的案例研究，进一步加强了研究与教学的结合。这包括与林务局植物学家就土地利用规划进行协商，以及向各团体作介绍。加深对兰花与真菌关系的了解具有直接的保护效益，因为真菌伴侣是兰花发芽和生长所必需的。试图维持或重新引入濒危兰花物种的计划必须解决真菌伴侣身份和可用性的问题。

0415920FreudensteinOrchids comprise the largest family of flowering plants and are extremely diverse. All are parasitic on fungi at least when seeds germinate, but little is known about this relationship. Some orchids depend on fungi for all nutrition because they are non-photosynthetic. Orchids of the genus Corallorhiza are prime examples, comprising 11 species of mainly North American temperate-montane terrestrials. This group provides a special opportunity to study the changes that happen when plants give up photosynthesis, because at least one species is photosynthetic while others are not. Such changes include partial loss of chloroplast DNA, structural modifications of the plant, and shifts among the groups of their associated fungi. Reconstructing phylogenetic relationships among populations of the species of Corallorhiza and their fungi through analysis of DNA sequences will reveal to what extent the orchid-fungal association is essentially random vs. targeted to certain fungal groups; adding orchid morphology and locality data will show whether shifts in fungal utilization are at all correlated with these factors. Because of the intensive sampling, any repeated correlations of present-day distribution with lineage histories will be shown, which might reflect post-glacial migration. This will provide a better understanding of how current plant distributions in North America came to be. The project incorporates carefully planned fieldwork to obtain both orchid and fungal samples, and brings together the expertise of orchid specialist John Freudenstein at Ohio State University and fungal specialist Donald Taylor at University of Alaska to facilitate a comprehensive analysis that would not otherwise be possible, yielding perhaps the most detailed and multifaceted analysis of a plant-microbe interaction to date.This project has broad impact for science and beyond in a number of ways. It provides a synthesis of modern approaches to a detailed analysis of flowering plant-fungal associations, plant morphology, gene lineages and geography. As such, it may serve as a model for future work on similar systems. It enhances the infrastructure of science by bringing new collections of these taxa into museums where they have broad accessibility and the DNA sequences generated into public databases where they will be available to all. The interactions with scientists in China, Korea and Mexico will result in strengthened networks of cooperation. The project brings together research and education by integrating graduate and undergraduate students in the project. It further enhances the integration of research and teaching by utilization of the results of the project as a case study in the PIs' teaching in courses on systematics, microbial diversity and symbiosis, and in their outreach to the public at large. This includes ongoing consultation with forest service botanists on land use planning, as well as presentations to various groups. Increased understanding of orchid-fungus relationships has direct conservation benefits, since fungal partners are required for orchid germination and growth. Programs that attempt to maintain or reintroduce endangered species of orchids must address the issue of fungal partner identity and availability.