Metagenomic and metatranscriptomic analysis of S(0) rich microbial community reveals genetic diversity and ecological success of the genus Sulfurovum
Abstract
Elemental sulfur (S(0)) is an important geologic resource, yet we are still understanding the mechanisms by which S-oxidizing microbial communities facilitate its formation. The Pozzo dei Cristalli stream in the Frasassi Cave System is inhabited by Sulfurovum streamers rich in S(0), implying a microbial role in mineral formation. Using a multi-omics approach, we examined how the community functions to make S(0), and more specifically, the genetic diversity within the Sulfurovum. Metagenomes and 16S rRNA were sequenced from colonization net samples over 17 days, and revealed a simple community structure with two taxa making up 75% to 95% of the community abundance: a Gammaproteobacteria Halothiobacillaceae (PC16-C1) and a Campylobacterota Sulfurovum (PC16-C2). We recovered 30 high-quality representative metagenome assembled genomes (MAGs), including seven Sulfurovum. Transcripts mapping to these MAGs show that the Sulfurovum conduct sulfur oxidation by multiple pathways (differing by MAG), aerobic respiration, denitrification, and carbon fixation. One Sulfurovum, PC16-C2, was by far the most abundant and active in the streamer community, suggesting it represents the streamer architect and primary producer. Sulfurovum PC16-C2 highly expressed sqr, which would lead to S(0) formation, likely making PC16-C2 the primary contributor of S(0). To understand the role of the flanking Sulfurovum (seven in total), we performed a pangenomic analysis, which revealed that 21% to 35% of the Sulfurovum MAGs are core, shared genes, while 12% to 44% were strain specific. All but one Sulfurovum MAG has sqr, but they vary in sox gene content. Remarkably, the seven Frasassi Sulfurovum MAGs span the phylogenetic diversity of the Sulfurovum. We are currently conducting a comprehensive Sulfurovum pangenomic analysis using a set of 38 marine and terrestrial genomes/MAGs to understand what genes are specific to the Frasassi Cave, and how representative the Frasassi Sulfurovum are of their phylogenetic group. Our initial observations show that phylogeny may play a stronger role in determining genetic potential, suggesting that we can use the Frasassi Sulfurovum genomes to learn more generally what genes drive the diversity and success of this cosmopolitan group of S-oxidizers, and ultimately niches of biogenic S(0) formation
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B23H2618P
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCESDE: 0463 Microbe/mineral interactions;
- BIOGEOSCIENCESDE: 0470 Nutrients and nutrient cycling;
- BIOGEOSCIENCES