Geography and climate drive the distribution and diversification of the cosmopolitan cyanobacterium <i>Microcoleus</i> (Oscillatoriales, Cyanobacteria)

Despite the extensive diversity of bacteria and their importance to the fundamental functioning of terrestrial ecosystems, their distribution patterns are still not fully known. To fill the gap and further understand the biogeographic patterns in bacteria, we investigated the phylogeographic structure and the underlying drivers of diversification among populations of the cyanobacterium <i>Microcoleus</i> spp. The phylogenetic history was reconstructed using 16S rRNA genes and the 16S–23S internal transcribed spacer (ITS) of 495 <i>Microcoleus</i> spp. isolates. Ancestral area and state reconstruction was employed to investigate the distributional and ecological patterns within <i>Microcoleus</i>. Both isolation by distance and isolation by environment were tested with distance matrices analysis. The phylogenetic signal tests were conducted in order to assess the influence of the climatic preferences on the diversification of <i>Microcoleus</i> isolates. The distribution and phylogenetic diversification of <i>Microcoleus</i> are driven by both isolation by distance and environment, leading to at least 13 distinct lineages that could represent novel cyanobacterial species. <i>Microcoleus</i> spp. exhibited a distinct phylogeographic structure within the respective lineages. The ancestral area and state reconstruction revealed that <i>Microcoleus</i> most likely arose in Europe in terrestrial habitats. The phylogenetic signal showed that the phylogeny significantly affects the climatic preferences of <i>Microcoleus</i> strains. Geographic distance and contemporary climatic conditions play significant roles in shaping the distribution and diversification of <i>Microcoleus</i>. The observed patterns of distribution may shift in the future due to the impact of climate change. Highlights <i>Microcoleus</i> exhibited distinct phylogeographic structure within the respective lineages.Geographic and environmental heterogeneity affect <i>Microcoleus</i> distribution and diversification.Genetically distinct lineages coexist at the same site. <i>Microcoleus</i> exhibited distinct phylogeographic structure within the respective lineages. Geographic and environmental heterogeneity affect <i>Microcoleus</i> distribution and diversification. Genetically distinct lineages coexist at the same site.

尽管细菌具有极为丰富的多样性，且对陆地生态系统的核心功能至关重要，但其分布格局迄今仍未被完全探明。为填补这一研究空白，进一步解析细菌的生物地理分布模式，我们针对蓝细菌微鞘藻属（*Microcoleus*）各种群的系统地理结构及其多样化的潜在驱动因素展开了研究。

我们基于495株微鞘藻属分离株的16S rRNA基因及16S–23S内部转录间隔区（ITS）序列，重构了其系统发育历史。我们采用祖先区域与性状重建方法，解析了微鞘藻属的分布与生态格局。通过距离矩阵分析，我们分别检验了距离隔离与环境隔离效应。为评估气候偏好对微鞘藻属分离株多样化的影响，我们开展了系统发育信号检测。

研究结果显示，微鞘藻属的分布与系统发育多样化同时受距离隔离与环境隔离驱动，由此形成了至少13个可代表新蓝细菌物种的独立演化支。微鞘藻属各独立演化支内部均呈现出清晰的系统地理结构。祖先区域与性状重建结果表明，微鞘藻属最有可能起源于欧洲的陆地生境中。系统发育信号检测结果表明，系统发育关系显著影响微鞘藻属菌株的气候偏好性。地理距离与现代气候条件在塑造微鞘藻属的分布格局与多样化进程中发挥了重要作用。受气候变化影响，当前观测到的分布格局未来可能发生改变。

【研究亮点】
1. 微鞘藻属各独立演化支内部均呈现出清晰的系统地理结构；
2. 地理与环境异质性可影响微鞘藻属的分布与多样化进程；
3. 遗传分化显著的演化支可在同一位点共存。

搜集汇总

背景与挑战

背景概述

该数据集研究了地理和气候因素对蓝藻Microcoleus分布和多样化的驱动作用，基于495个分离株的系统发育分析，识别出至少13个可能的新物种谱系，并发现Microcoleus可能起源于欧洲陆地生境。研究结果表明，地理距离和当代气候条件共同塑造了其分布模式，且同一地点可存在遗传不同的谱系，这些模式可能受未来气候变化影响。