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Abstract：
Biotic and abiotic factors influence the formation of fungal-algal pairings in lichen symbiosis. However, the specific determinants of these associations, particularly when distantly related fungi are involved, remain poorly understood. In this study, we investigated the impact of different drivers on the association patterns between taxonomically diverse lichenized fungi and their trebouxioid symbiotic partners. We collected 200 samples from four biomes and identified 41 species of lichenized fungi, associating them with 16 species of trebouxioid green algae, of which 62% were previously unreported. The species identity of both the fungal and algal partners had the most significant effect on the outcome of the symbiosis, compared to abiotic factors like climatic variables and geographic distance. Some obviously specific associations were observed in the temperate zone; however, the nestedness value was lower in arid regions than in cold, polar, and temperate regions according to interaction network analysis. Cophylogenetic analyses revealed congruent phylogenies between trebouxioid algae and associated fungi, indicating a tendency to reject random associations. The main evolutionary mechanisms contributing to the observed phylogenetic patterns were \"loss\" and \"failure to diverge\" of the algal partners. This study broadens our knowledge of fungal-algal symbiotic patterns in view of Trebouxia-associated fungi.
摘要：
生物和非生物因素影响地衣共生中真菌-藻类配对的形成。然而,这些关联的具体决定因素，特别是当涉及远缘真菌时，仍然知之甚少。在这项研究中,我们调查了不同驱动因素对分类学上不同的苔藓真菌与其树状共生伙伴之间的关联模式的影响。我们从四个生物群落中收集了200个样本，并鉴定了41种地衣真菌，将它们与16种树状绿藻相关联，其中62%以前未报告。真菌和藻类伴侣的物种身份对共生的结果影响最大，与气候变量和地理距离等非生物因素相比。在温带地区观察到一些明显的特定关联；然而，干旱地区的嵌套值低于寒冷地区，极地,根据相互作用网络分析，温带地区。共生分析显示，树状藻类和相关真菌之间存在一致的系统发育，表明倾向于拒绝随机关联。导致观察到的系统发育模式的主要进化机制是藻类伴侣的“丢失”和“无法发散”。鉴于Trebouxia相关真菌，这项研究拓宽了我们对真菌-藻类共生模式的认识。
