PDF(Pubmed)
Abstract：
Bacterial genome size reflects bacterial evolutionary processes and metabolic lifestyles, with implications for microbial community assembly and ecosystem functions. However, to understand the extent of genome-mediated microbial responses to environmental selections, we require studies that observe genome size distributions along environmental gradients representing different conditions that soil bacteria normally encounter. In this study, we used surface soils collected from 237 sites across the globe and analyzed how environmental conditions (e.g., soil carbon and nutrients, aridity, pH, and temperature) affect soil bacterial occurrences and genome size at the community level using bacterial community profiling. We used a joint species distribution model to quantify the effects of environments on species occurrences and found that aridity was a major regulator of genome size with warmer and drier environments selecting bacteria with smaller genomes. Drought-induced physiological constraints on bacterial growth (e.g., water scarcity for cell metabolisms) may have led to these correlations. This finding suggests that increasing cover by warmer and drier ecosystems may result in bacterial genome simplifications by a reduction of genome size.
摘要：
细菌基因组大小反映了细菌的进化过程和代谢生活方式，对微生物群落组装和生态系统功能具有重要意义。然而,为了了解基因组介导的微生物对环境选择的反应程度，我们需要研究观察基因组大小分布沿环境梯度代表土壤细菌通常遇到的不同条件。在这项研究中,我们使用了从全球237个地点收集的地表土壤，并分析了环境条件(例如，土壤碳和养分，干旱,pH值,和温度）使用细菌群落分析在群落水平上影响土壤细菌的发生和基因组大小。我们使用联合物种分布模型来量化环境对物种发生的影响，发现干旱是基因组大小的主要调节因子，而温暖和干燥的环境选择基因组较小的细菌。干旱对细菌生长的生理限制(例如，细胞代谢的缺水)可能导致了这些相关性。这一发现表明，增加温暖和干燥的生态系统的覆盖率可能会通过减少基因组大小而导致细菌基因组简化。
