Lichens are classic models of symbiosis, and one of the most frequent nutritional modes among fungi. The ecologically and geographically widespread lichen-forming algal (LFA) genus Trebouxia is one of the best-studied groups of LFA and associates with over 7000 fungal species. Despite its importance, little is known about its diversification. We synthesized twenty years of publicly available data by characterizing the ecological preferences of this group and testing for time-variant shifts in climatic regimes over a distribution of trees. We found evidence for limited shifts among regimes, but that disparate lineages convergently evolved similar ecological tolerances. Early Trebouxia lineages were largely forest specialists or habitat generalists that occupied a regime whose extant members occur in moderate climates. Trebouxia then convergently diversified in non-forested habitats and expanded into regimes whose modern representatives occupy wet-warm and cool-dry climates. We rejected models in which climatic diversification slowed through time, suggesting climatic diversification is inconsistent with that expected under an adaptive radiation. In addition, we found that climatic and vegetative regime shifts broadly coincided with the evolution of biomes and associated or similar taxa. Together, our work illustrates how this keystone symbiont from an iconic symbiosis evolved to occupy diverse habitats across the globe.

中文翻译：

---

基石共生体进化枝中的宏观生态多样化和趋同

地衣是共生的经典模式，也是真菌中最常见的营养模式之一。生态和地理上广泛分布的地衣形成藻 (LFA) 属 Trebouxia 是 LFA 研究最好的群体之一，与 7000 多种真菌物种有关。尽管它很重要，但人们对其多样化知之甚少。我们通过表征该群体的生态偏好并测试气候状况在树木分布上的时变变化，综合了 20 年的公开数据。我们发现了政权之间有限转变的证据，但不同的谱系趋同进化出相似的生态耐受性。早期的 Trebouxia 世系主要是森林专家或栖息地通才，他们占据了一个现存成员出现在温和气候中的政权。然后，Trebouxia 在非森林栖息地中趋同多样化，并扩展到现代代表占据湿热和冷干气候的政权。我们拒绝了气候多样化随时间减缓的模型，这表明气候多样化与自适应辐射下的预期不一致。此外，我们发现气候和植物系统的变化与生物群落和相关或类似分类群的演变大体一致。总之，我们的工作说明了这种来自标志性共生体的关键共生体是如何进化成占据全球不同栖息地的。表明气候多样化与适应性辐射下的预期不一致。此外，我们发现气候和植物系统的变化与生物群落和相关或类似分类群的演变大体一致。总之，我们的工作说明了这种来自标志性共生体的关键共生体是如何进化成占据全球不同栖息地的。表明气候多样化与适应性辐射下的预期不一致。此外，我们发现气候和植物系统的变化与生物群落和相关或类似分类群的演变大体一致。总之，我们的工作说明了这种来自标志性共生体的关键共生体是如何进化成占据全球不同栖息地的。