Coevolution between algae and fungi in lichen associations

地衣是研究最不充分的生物之一，也是对环境变化最敏感的生物之一，但对构成地衣群落的藻类和真菌共生伙伴关系的共同进化知之甚少。广泛分布的克拉多尼亚属包括在稳定环境中生长的物种（驯鹿地衣；克拉多尼亚rangiferina及其盟友）和在不稳定的干扰地点生长的物种（Pixie cup地衣；克拉多尼亚pyxidata及其盟友）。本研究的目的是研究生长在不同栖息地的两组物种（驯鹿和精灵杯地衣）中每种藻类和真菌基因组以及共生体之间的遗传变异模式，以确定：1)物种和种群之间的进化关系；2)繁殖和交配系统模式；3)每种共生体的种群结构。这些目标将使用每个藻类和真菌伙伴的核和线粒体标记进行检查。本研究将说明地理和分类尺度在共同进化研究中的重要性，种群水平的活动可能决定更高分类水平上的共同进化关系，以及先锋地衣和顶极地衣在适应机制上可能存在重要差异。这些研究也将有助于了解珍稀濒危物种或入侵和广泛分布物种的适应情况。这些信息对于实施基于科学的自然资源管理战略非常重要。

Summary of proposed research Coevolution between algae and fungi in lichen associations Lichens are among the most understudied organisms and the most sensitive to environmental changes with little known about the co-evolving symbiotic partnership between algal and fungal symbionts that make up lichen associations. The widespread genus Cladonia contains species that grow in stable environments (Reindeer lichens; Cladonia rangiferina and allies) and species that grow in unstable disturbed sites (Pixie cup lichens; Cladonia pyxidata and allies). The objectives of this research are to examine patterns of genetic variation in each of the algal and fungal genomes and between symbionts for two groups of species that grow in different habitats (reindeer and pixie cup lichens) to determine: 1) evolutionary relationships among species and populations, 2) mode of reproduction and mating system, and 3) population structure for each of the symbionts. These objectives will be examined using nuclear and mitochondrial markers for each of the algal and fungal partners. This research will illustrate the importance of geographic and taxonomic scale in coevolutionary studies, that population level activity may determine coevolutionary relationships at higher taxonomic levels, and that there may be important differences in the mechanisms of adaptation between pioneer and climax lichens. These studies will also shed light on the understanding of adaptation in rare and endangered species or invasive and widespread species. This information is important for implementing science-based management strategies of natural resources.