A wetland soil community in which terrestrial Asgard archaea modulate potential methanogenesis substrates. Two complete genomes were reconstructed for soil-associated Atabeyarchaeia, a newly defined Asgard lineage, alongside a complete genome for Freyarchaeia. Metatranscriptomic data show in situ expression of [NiFe]-hydrogenases, pyruvate oxidation, Wood-Ljungdahl-pathway carbon fixation, amino acid metabolism, anaerobic aldehyde oxidation, hydrogen peroxide detoxification, and carbohydrate breakdown to acetate and formate. Soil-associated Asgard archaea are predicted to act as non-methanogenic acetogens, suggesting that they modulate wetland-soil methanogenesis substrate pools (H2, acetate, formate) and shape terrestrial carbon cycling.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Atabeyarchaeia (Asgard) — ontology label: Promethearchaeati | NCBITaxon:1935183 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
SECONDARY_FERMENTER
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N/A |
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| Freyarchaeia (Asgard) — ontology label: Promethearchaeati | NCBITaxon:1935183 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
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| wetland soil methanogens — ontology label: Archaea | NCBITaxon:2157 · TaxonMech · TraitMech |
PRIMARY_PRODUCER
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N/A |
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Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
Asgard Acetogenesis Modulates Methanogenic Substrates
HYPOTHESIZED - genomes and transcripts suggest non-methanogenic Asgard acetogens can produce or consume acetate, formate and hydrogen-linked carbon pools. Hydrogen consumption could reduce methanogen substrate supply, while acetate production could support acetoclastic methanogens; neither realized transfer nor the net methane effect was resolved.
Participating Taxa: Atabeyarchaeia (Asgard), Freyarchaeia (Asgard), wetland soil methanogens
Metabolites: dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), acetate (CHEBI:30089 · MediaIngredientMech · CMMMech), formate (CHEBI:15740 · MediaIngredientMech · CMMMech)
Evidence
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PMID:39085194 - PARTIAL (COMPUTATIONAL)"soil-associated Asgard archaea are predicted to include non-methanogenic acetogens"
Wood-Ljungdahl Carbon Fixation and Hydrogen Cycling
COMPUTATIONAL POTENTIAL - detected Wood-Ljungdahl and hydrogenase transcripts support an expressed metabolic capacity. The pathway is reversible: carbon fixation and reverse acetate oxidation are possible, and transcript presence does not determine direction or hydrogen flux.
Participating Taxa: Atabeyarchaeia (Asgard), Freyarchaeia (Asgard)
Metabolites: dihydrogen (CHEBI:18276 · MediaIngredientMech · CMMMech), carbon dioxide (CHEBI:16526 · MediaIngredientMech · CMMMech)
Biological Processes:
- carbon fixation (GO:0015977 · PathwayMech)
HYPOTHESIZED - expressed Wood-Ljungdahl/hydrogenase capacity could alter methanogenic substrate pools through production or consumption. Direction, exchanged flux and net methanogen response remain unresolved.
Evidence
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PMID:39085194 - PARTIAL (COMPUTATIONAL)"pyruvate oxidation and carbon fixation via the Wood-Ljungdahl pathway"
Carbohydrate Breakdown to Acetate and Formate
COMPUTATIONAL POTENTIAL - genome/transcript reconstructions suggest carbohydrate conversion to acetate and formate. Freyarchaeia encode predicted glucose use, whereas Atabeyarchaeia entry is proposed through phosphorylated sugars. These are lineage-dependent capacities, not measured release of identical products by both groups.
Participating Taxa: Atabeyarchaeia (Asgard), Freyarchaeia (Asgard)
Metabolites: acetate (CHEBI:30089 · MediaIngredientMech · CMMMech), formate (CHEBI:15740 · MediaIngredientMech · CMMMech)
Biological Processes:
- carbohydrate metabolic process (GO:0005975 · PathwayMech)
HYPOTHESIZED - realized carbohydrate metabolism could supply acetate/formate to shared pools, but these compounds can also be consumed and no partner-resolved transfer or methane response was measured.
Evidence
-
PMID:39085194 - PARTIAL (COMPUTATIONAL)"carbohydrate breakdown to acetate and formate"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which Asgard fluxes produce or consume methanogenic substrates under native soil conditions?
PMID:39085194 reports genomic and transcript evidence, not a resolved carbon/hydrogen balance. Reversible pathway direction, hydrogenase function and methanogen responses need biochemical or tracer discrimination. Pooled homogenized RNA without technical replicates does not resolve replicated depth-specific ecosystem effects.
Attaches to: ecological_interactions#Asgard Acetogenesis Modulates Methanogenic Substrates, ecological_interactions#Wood-Ljungdahl Carbon Fixation and Hydrogen Cycling, ecological_interactions#Carbohydrate Breakdown to Acetate and Formate
External Resources
| Name | Repository | Resource ID |
|---|---|---|
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Primary publication for the Asgard wetland soil methanogenesis-substrate community
PubMed record for the Valentin-Alvarado et al. 2024 Nat Commun paper on Asgard archaeal contributions to wetland-soil methanogenesis substrate cycling. |
OTHER | PMID:39085194 |
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DOI landing page
DOI link to the Nature Communications paper. |
OTHER | doi:10.1038/s41467-024-49872-z |
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Wetland soil anaerobic niche | wetland soil | N/A |
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