COLLABORATIVE RESERARCH: Symbiosis and Repercussions of Extreme Ecological Specificity

非光合作用植物Pterospora andromedea依靠与根霉属真菌的专性关系来获得碳和能量。这种真菌反过来依赖于与针叶树的专有联系来获得其碳和能量。人们对这种复杂的三方共生现象研究甚少。然而，在人类干扰或气候变化的条件下，对关系中高度具体的联系的极端依赖可能会导致种群数量下降。事实上，北美东部的翼孢霉种群数量急剧下降，但在西部似乎是安全的。这项拟议的研究将调查北美各地的蕨类/根霉属植物对的历史联系、共同迁徙和遗传结构。中心假设是，这种关系的健康和活力将在其地理范围的中心(如太平洋西北)最高，而存在于这一最佳中心之外的种群，包括那些不连续的或分布在山脉边缘的种群(新英格兰)，将表现出较低的相对丰度和较高的遗传分化，这可能是由于遗传漂移和基因流动的影响增加。这项调查将阐明这种复杂的植物-真菌共生的历史模式和生态专一性的变化，并确定在社区水平上解释共生体种群遗传结构的当代模式的因素。这是一个合作项目，涉及两个研究团队之间互补专业知识的协同融合，一个来自一所小型的文理学院(中心学院)，另一个来自研究密集型大学(怀俄明大学)。这一合作将支持一名博士后学者和几名研究生的研究、培训和指导。此外，这项研究将从根本上改善以农村本科生为主的大学的文科学习环境，提供一个充满活力的研究机会，刺激本科生的科学发展，并提供一个有意义的指导机会。

The non-photosynthetic plant Pterospora andromedea relies on an obligate relationship with a fungus in the genus Rhizopogon to obtain carbon and energy. This fungus in turn relies on an obligate association with conifer trees to obtain its carbon and energy. Such complex tripartite symbioses have been little studied. However, under conditions of human disturbance or climate change, extreme dependence on highly specific associations within the relationships may lead to population decline. Indeed, populations of Pterospora are in steep decline in eastern North America, but appear to be secure in the west. The proposed research will investigate the historic association, co-migration and genetic structure in Pterospora/Rhizopogon pairs from across North America. The central hypothesis is that health and vigor of this relationship will be highest in the center of its geographic range (e.g. Pacific Northwest) and that populations that exist outside of this optimal center, including those that are disjunct or at range margins (New England), will exhibit lower relative abundance and higher genetic differentiation, possibly due to increased effects of genetic drift and reduced gene flow. This investigation will elucidate historic patterns and variation in ecological specificity in this complex plant-fungal symbiosis and determine factors that explain contemporary patterns of population genetic structure of symbionts at the community level.This is a collaborative project that involves the synergistic melding of complementary expertise between two research teams, one from a small, liberal arts college (Centre College) and the other at a research intensive University (U of Wyoming). This collaboration will support research training and mentoring of a postdoctoral scholar, and several graduate students. Further, this research will fundamentally enhance the liberal arts learning environment at a primarily rural undergraduate institution by providing a dynamic research opportunity to stimulate the scientific development of undergraduate students and a meaningful mentorship opportunity.