Evolutionary dynamics of lichen-forming algae fungi and natural products

藻类和真菌成分相互作用产生地衣关联，形成一个复杂的菌体，不像两个共生伙伴中的任何一个单独。在自然界中已经报道了菌体的形态变化，并与环境条件的变化有关。地衣适应不断变化的条件的能力对它们的生存能力至关重要，特别是在目前北方气候变化的情况下，驯鹿地衣的成员占主导地位，是大型哺乳动物冬季饮食的重要组成部分。地衣很难在培养基中生长，因此在控制条件下研究地衣的形态变化是很困难的。但在培养中很容易测量的一个表型特征是自然产物（次生代谢物）的产生。这些代谢物的基因已经被描述，使基因表达成为一种可测量的表型，随着培养条件的变化，反映环境条件的变化。本研究计划的总体目标是了解地衣形成真菌物种之间的进化关系，以及共生体如何受到环境条件变化的影响。这将揭示推动地衣生物多样性的机制。一名博士生正在研究Ramalina属成员之间的进化关系，以及该属成员产生的次生代谢物的进化。另一名博士生正在研究驯鹿地衣（Cladonia sect. Cladina）的进化，以更好地了解有性繁殖和这组地衣适应不断变化的环境条件的能力。地衣真菌选择适应栖息地的藻类被认为是一种生存策略，因为真菌孢子分散到不同的栖息地。两名硕士研究生将研究水生地衣和陆生地衣中的藻类选择，以了解这些物种如何适应水位、污染水平或环境光和温度的变化。更好地了解次生代谢物的适应和环境调节可以在不消耗自然资源的情况下提供更好的药物化合物。

The algal and fungal components that interact to produce a lichen association, form a complex thallus unlike either of the two symbiotic partners alone. Morphological changes in the thallus have been reported in nature and correlated with changes in environmental conditions. The ability of lichens to adapt to changing conditions is instrumental to their ability to survive especially under the current climate change in the north where members of the Reindeer lichens dominate and form an important component of the winter diet for large mammals. It is difficult to study morphological changes in lichens under controlled culture conditions because lichens are so difficult to grow in culture. But one phenotypic feature that is readily measured in culture is the production of natural products (secondary metabolites). The genes for these metabolites have been described making gene expression a measurable phenotype with changes in culture conditions that reflect changes in environmental conditions. The general goal of this research program is to understand the evolutionary relationships among species of lichen-forming fungi, and how the symbionts are affected by changes in environmental conditions. This will shed light on the mechanisms that drive biodiversity in lichens. One PhD student is studying the evolutionary relationships among members of the genus Ramalina with respect to evolution of the secondary metabolites produced by members of the genus. Another PhD student is examining evolution of the Reindeer lichens (Cladonia sect. Cladina) to better understand sexual reproduction and the ability of this group of lichens to adapt to changing environmental conditions. The selection of algae adapted to the habitat by lichen fungi is thought to be a strategy for survival as the fungal spores are dispersed to different habitats. Two MSc students will examine algal selection in an aquatic lichen and a terrestrial lichen to understand how these species might adapt to changes in water levels or pollution levels or to changes in ambient light and temperature. A better understanding of adaptation and environmental regulation of secondary metabolites may provide better pharmaceutical compounds without depleting our natural resources.