Evolution of Networks Lab, Institute of Evolutionary Biology (UPF-CSIC), Passeig Marítim de la Barceloneta 37, Barcelona, 08003, Spain.
European Centre for Living Technology (ECLT), Ca' Bottacin, Dorsoduro 3911, Venezia, 30123, Italy.
Sci Rep. 2023 Feb 25;13(1):3295. doi: 10.1038/s41598-023-30357-w.
Symbiosis is a major engine of evolutionary innovation underlying many extant complex organisms. Lichens are a paradigmatic example that offers a unique perspective on the role of symbiosis in ecological success and evolutionary diversification. Lichen studies have produced a wealth of information regarding the importance of symbiosis, but they frequently focus on a few species, limiting our understanding of large-scale phenomena such as guilds. Guilds are groupings of lichens that assist each other's proliferation and are intimately linked by a shared set of photobionts, constituting an extensive network of relationships. To characterize the network of lichen symbionts, we used a large data set ([Formula: see text] publications) of natural photobiont-mycobiont associations. The entire lichen network was found to be modular, but this organization does not directly match taxonomic information in the data set, prompting a reconsideration of lichen guild structure and composition. The multiscale nature of this network reveals that the major lichen guilds are better represented as clusters with several substructures rather than as monolithic communities. Heterogeneous guild structure fosters robustness, with keystone species functioning as bridges between guilds and whose extinction would endanger global stability.
共生是进化创新的主要引擎，为许多现存的复杂生物提供了基础。地衣是一个典范的例子，它提供了一个独特的视角，说明了共生在生态成功和进化多样化中的作用。地衣研究产生了大量关于共生重要性的信息，但它们经常集中在少数几个物种上，限制了我们对大规模现象（如类群）的理解。类群是相互帮助繁殖的地衣群体，通过共享的一套光合生物紧密相连，构成了一个广泛的关系网络。为了描述地衣共生体的网络，我们使用了一个包含[Formula: see text]篇文献的大型自然光合生物-共生菌联合体数据。整个地衣网络被发现是模块化的，但这种组织与数据集的分类信息并不直接匹配，促使我们重新考虑地衣类群的结构和组成。这个网络的多尺度性质表明，主要的地衣类群与其说是单一的群落，不如说是由几个亚结构组成的聚类。异质的类群结构促进了稳健性，关键物种充当了类群之间的桥梁，如果它们灭绝，将危及全球稳定。
