Mixotrophy drives niche expansion of verrucomicrobial methanotrophs
| Autor: | Matthew B. Stott, Ben McDonald, Richard Sparling, Gregory M. Cook, Christophe Collet, Kiel Hards, Jean F. Power, Daniel J. Gapes, Carlo R Carere, Eric S. Boyd, Chris Greening, Karen M. Houghton |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Methanotroph 030106 microbiology Biology Microbiology Methane 03 medical and health sciences chemistry.chemical_compound Soil Bacterial Proteins Hydrogenase Verrucomicrobia Methylacidiphilum fumariolicum Ecology Evolution Behavior and Systematics Phylogeny Soil Microbiology Autotrophic Processes Ecology Geomicrobiology Carbon fixation Genomics Oxygen Environmental biotechnology chemistry Environmental chemistry Original Article Soil microbiology Oxidation-Reduction New Zealand |
| Zdroj: | The ISME Journal |
| ISSN: | 1751-7370 1751-7362 |
| Popis: | Aerobic methanotrophic bacteria have evolved a specialist lifestyle dependent on consumption of methane and other short-chain carbon compounds. However, their apparent substrate specialism runs contrary to the high relative abundance of these microorganisms in dynamic environments, where the availability of methane and oxygen fluctuates. In this work, we provide in situ and ex situ evidence that verrucomicrobial methanotrophs are mixotrophs. Verrucomicrobia-dominated soil communities from an acidic geothermal field in Rotokawa, New Zealand rapidly oxidised methane and hydrogen simultaneously. We isolated and characterised a verrucomicrobial strain from these soils, Methylacidiphilum sp. RTK17.1, and showed that it constitutively oxidises molecular hydrogen. Genomic analysis confirmed that this strain encoded two [NiFe]-hydrogenases (group 1d and 3b), and biochemical assays revealed that it used hydrogen as an electron donor for aerobic respiration and carbon fixation. While the strain could grow heterotrophically on methane or autotrophically on hydrogen, it grew optimally by combining these metabolic strategies. Hydrogen oxidation was particularly important for adaptation to methane and oxygen limitation. Complementary to recent findings of hydrogenotrophic growth by Methylacidiphilum fumariolicum SolV, our findings illustrate that verrucomicrobial methanotrophs have evolved to simultaneously utilise hydrogen and methane from geothermal sources to meet energy and carbon demands where nutrient flux is dynamic. This mixotrophic lifestyle is likely to have facilitated expansion of the niche space occupied by these microorganisms, allowing them to become dominant in geothermally influenced surface soils. Genes encoding putative oxygen-tolerant uptake [NiFe]-hydrogenases were identified in all publicly available methanotroph genomes, suggesting hydrogen oxidation is a general metabolic strategy in this guild. |
| Databáze: | OpenAIRE |
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