Figueroa-Gonzalez Perla Abigail, Bornemann Till L V, Adam Panagiotis S, Plewka Julia, Révész Fruzsina, von Hagen Christian A, Táncsics András, Probst Alexander J
Group for Aquatic Microbial Ecology, Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
Regional University Center of Excellence in Environmental Industry, Szent István University, Gödöllõ, Hungary.
Front Microbiol. 2020 Dec 23;11:587782. doi: 10.3389/fmicb.2020.587782. eCollection 2020.
Organisms of the candidate phylum Saccharibacteria have frequently been detected as active members of hydrocarbon degrading communities, yet their actual role in hydrocarbon degradation remained unclear. Here, we analyzed three enrichment cultures of hydrocarbon-amended groundwater samples using genome-resolved metagenomics to unravel the metabolic potential of indigenous Saccharibacteria. Community profiling based on ribosomal proteins revealed high variation in the enrichment cultures suggesting little reproducibility although identical cultivation conditions were applied. Only 17.5 and 12.5% of the community members were shared between the three enrichment cultures based on ribosomal protein clustering and read mapping of reconstructed genomes, respectively. In one enrichment, two Saccharibacteria strains dominated the community with 16.6% in relative abundance and we were able to recover near-complete genomes for each of them. A detailed analysis of their limited metabolism revealed the capacity for peptide degradation, lactate fermentation from various hexoses, and suggests a scavenging lifestyle with external retrieval of molecular building blocks. In contrast to previous studies suggesting that Saccharibacteria are directly involved in hydrocarbon degradation, our analyses provide evidence that these organisms can be highly abundant scavengers acting rather as organic carbon sinks than hydrocarbon degraders in these communities.
候选门糖菌纲的微生物经常被检测为烃降解群落的活跃成员，但其在烃降解中的实际作用仍不清楚。在这里，我们使用基因组解析宏基因组学分析了三种添加烃的地下水样品富集培养物，以揭示本地糖菌纲的代谢潜力。基于核糖体蛋白的群落分析表明，尽管采用了相同的培养条件，但富集培养物中存在很大差异，这表明重现性较差。基于核糖体蛋白聚类和重建基因组的读数映射，三种富集培养物中分别只有17.5%和12.5%的群落成员相同。在一次富集培养中，两种糖菌纲菌株在群落中占主导地位，相对丰度为16.6%，我们能够为它们各自获得近乎完整的基因组。对其有限代谢的详细分析揭示了肽降解能力、各种己糖的乳酸发酵能力，并表明其具有通过外部获取分子构件的 scavenging 生活方式。与之前认为糖菌纲直接参与烃降解的研究不同，我们的分析提供了证据，表明这些微生物在这些群落中可以是高度丰富的 scavengers，它们更像是有机碳汇而不是烃降解者。
