Babilonia Joany, Conesa Ana, Casaburi Giorgio, Pereira Cecile, Louyakis Artemis S, Reid R Pamela, Foster Jamie S
Space Life Science Lab, Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, United States.
Department of Microbiology and Cell Science, Genetics Institute, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States.
Front Microbiol. 2018 Jun 25;9:1359. doi: 10.3389/fmicb.2018.01359. eCollection 2018.
Stromatolites are organosedimentary build-ups that have formed as a result of the sediment trapping, binding and precipitating activities of microbes. Today, extant systems provide an ideal platform for understanding the structure, composition, and interactions between stromatolite-forming microbial communities and their respective environments. In this study, we compared the metagenomes of three prevalent stromatolite-forming microbial mat types in the Spaven Province of Hamelin Pool, Shark Bay located in Western Australia. These stromatolite-forming mat types included an intertidal pustular mat as well as a smooth and colloform mat types located in the subtidal zone. Additionally, the metagenomes of an adjacent, non-lithifying mat located in the upper intertidal zone were also sequenced for comparative purposes. Taxonomic and functional gene analyses revealed distinctive differences between the lithifying and non-lithifying mat types, which strongly correlated with water depth. Three distinct populations emerged including the upper intertidal non-lithifying mats, the intertidal pustular mats associated with unlaminated carbonate build-ups, and the subtidal colloform and smooth mat types associated with laminated structures. Functional analysis of metagenomes revealed that amongst stromatolite-forming mats there was an enrichment of photosynthesis pathways in the pustular stromatolite-forming mats. In the colloform and smooth stromatolite-forming mats, however, there was an increase in the abundance of genes associated with those heterotrophic metabolisms typically associated with carbonate mineralization, such as sulfate reduction. The comparative metagenomic analyses suggest that stromatolites of Hamelin Pool may form by two distinctive processes that are highly dependent on water depth. These results provide key insight into the potential adaptive strategies and synergistic interactions between microbes and their environments that may lead to stromatolite formation and accretion.
叠层石是由于微生物的沉积物捕获、结合和沉淀活动而形成的有机沉积堆积物。如今，现存系统为理解形成叠层石的微生物群落及其各自环境之间的结构、组成和相互作用提供了一个理想平台。在本研究中，我们比较了位于西澳大利亚鲨鱼湾哈梅林池斯帕文省的三种常见的形成叠层石的微生物席类型的宏基因组。这些形成叠层石的席类型包括潮间带脓疱状席以及位于潮下带的光滑和柱状席类型。此外，还对位于潮间带上部的相邻非石化席的宏基因组进行了测序以作比较。分类学和功能基因分析揭示了石化席和非石化席类型之间的显著差异，这与水深密切相关。出现了三个不同的群体，包括潮间带上部的非石化席、与未层状碳酸盐堆积物相关的潮间带脓疱状席，以及与层状结构相关的潮下带柱状和光滑席类型。宏基因组的功能分析表明，在形成叠层石的席中，脓疱状形成叠层石的席中光合作用途径富集。然而，在柱状和光滑形成叠层石的席中，与那些通常与碳酸盐矿化相关的异养代谢相关的基因丰度增加，例如硫酸盐还原。比较宏基因组分析表明，哈梅林池的叠层石可能通过两个高度依赖水深的独特过程形成。这些结果为微生物与其环境之间可能导致叠层石形成和堆积的潜在适应策略和协同相互作用提供了关键见解。
