Bennett Alison E, Kelsey Scott, Saup Casey, Wilkins Mike, Malacrinò Antonino
Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH, USA.
School of Earth Sciences, The Ohio State University, Columbus, OH, USA.
Environ Microbiome. 2024 Nov 18;19(1):92. doi: 10.1186/s40793-024-00641-x.
Microbiomes, essential to ecosystem processes, face strong selective forces that can drive rapid evolutionary adaptation. However, our understanding of evolutionary processes within natural systems remains limited. We investigated evolution in response to naturally occurring selenium in soils of different geological parental materials on the Western Slope of Colorado. Our study focused on examining changes in gene frequencies within microbial communities in response to selenium exposure.
Despite expectations of taxonomic composition shifts and increased gene content changes at high-selenium sites, we found no significant alterations in microbial diversity or community composition. Surprisingly, we observed a significant increase in differentially abundant genes within high-selenium sites.
These findings are suggestive that selection within microbiomes primarily drives the accumulation of genes among existing microbial taxa, rather than microbial species turnover, in response to strong stressors like selenium. Our study highlights an unusual system that allows us to examine evolution in response to the same stressor annually in a non-model system, contributing to understanding microbiome evolution beyond model systems.
微生物群落对于生态系统过程至关重要，面临着能够推动快速进化适应的强大选择压力。然而，我们对自然系统内进化过程的理解仍然有限。我们研究了科罗拉多州西坡不同地质母质土壤中天然存在的硒所引发的进化。我们的研究重点是检查微生物群落内基因频率对硒暴露的响应变化。
尽管预期在高硒位点会出现分类组成变化和基因含量变化增加，但我们发现微生物多样性或群落组成没有显著改变。令人惊讶的是，我们观察到高硒位点内差异丰富基因显著增加。
这些发现表明，在微生物群落中，面对像硒这样的强应激源，选择主要驱动现有微生物类群间基因的积累，而非微生物物种更替。我们的研究突出了一个独特的系统，它使我们能够在非模式系统中每年检查对同一应激源的进化响应，有助于理解模型系统之外的微生物群落进化。
