| Autor: |
St. James, Andrew R., Yavitt, Joseph B., Zinder, Stephen H., Richardson, Ruth E. |
| Zdroj: |
The ISME Journal; January 2021, Vol. 15 Issue: 1 p293-303, 11p |
| Abstrakt: |
Ombrotrophic bogs accumulate large stores of soil carbon that eventually decompose to carbon dioxide and methane. Carbon accumulates because Sphagnummosses slow microbial carbon decomposition processes, leading to the production of labile intermediate compounds. Acetate is a major product of Sphagnumdegradation, yet rates of hydrogenotrophic methanogenesis far exceed rates of aceticlastic methanogenesis, suggesting that alternative acetate mineralization processes exist. Two possible explanations are aerobic respiration and anaerobic respiration via humic acids as electron acceptors. While these processes have been widely observed, microbial community interactions linking Sphagnumdegradation and acetate mineralization remain cryptic. In this work, we use ordination and network analysis of functional genes from 110 globally distributed peatland metagenomes to identify conserved metabolic pathways in Sphagnumbogs. We then use metagenome-assembled genomes (MAGs) from McLean Bog, a Sphagnumbog in New York State, as a local case study to reconstruct pathways of Sphagnumdegradation and acetate mineralization. We describe metabolically flexible AcidobacteriotaMAGs that contain all genes to completely degrade Sphagnumcell wall sugars under both aerobic and anaerobic conditions. Finally, we propose a hypothetical model of acetate oxidation driven by changes in peat redox potential that explain how bogs may circumvent aceticlastic methanogenesis through aerobic and humics-driven respiration. |
| Databáze: |
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