Chlorochromatium aggregatum Phototrophic Consortium

Community ID CommunityMech:000141

Ecological State STABLE

Environment anoxic sulfide-containing freshwater lake sediment
ENVO:01001242

A structured freshwater phototrophic bacterial consortium in which one central motile heterotrophic beta-proteobacterium, Candidatus Symbiobacter mobilis, is surrounded by approximately 15 green sulfur bacterial Chlorobium chlorochromatii epibionts. Genome analyses support a highly specialized symbiosis involving metabolite exchange, central-bacterium sensing and motility toward light and sulfide, cell-cell adhesion, and possible quinone-mediated electron exchange.

Taxonomy

Taxon	Ontology ID	Functional Roles	Abundance
Chlorobium chlorochromatii CaD3 epibiont	NCBITaxon:340177	PRIMARY_PRODUCER SYNTROPHIC_PARTNER	N/A
PMID:24267588 - SUPPORT (COMPUTATIONAL) "surrounded by approximately 15 epibiont cells of Chlorobium chlorochromatii" PMID:24267588 - SUPPORT (COMPUTATIONAL) "uses sulfide as the electron donor for photosynthetic CO2 and N2 fixation"
Candidatus Symbiobacter mobilis central bacterium	NCBITaxon:1436290	SYNTROPHIC_PARTNER CROSS_FEEDER	N/A
PMID:24267588 - SUPPORT (COMPUTATIONAL) "Candidatus Symbiobacter mobilis" PMID:24267588 - SUPPORT (COMPUTATIONAL) "is probably no longer capable of independent growth"

Ecological Interactions

Taxon

Cross-feeding

Mutualism

Syntrophy

Competition

Commensalism

Niche partitioning

Colonization facilitation

Strain competition

Predation

Phototroph To Central Bacterium Metabolite Exchange

SYNTROPHY

Source Taxon: Chlorobium chlorochromatii CaD3 epibiont

Target Taxon: Candidatus Symbiobacter mobilis central bacterium

Metabolites: carbon dioxide (CHEBI:16526), hydrogen sulfide (CHEBI:16136)

Biological Processes:

photosynthesis (GO:0015979)

Evidence

PMID:24267588 - SUPPORT (COMPUTATIONAL)

"extensive metabolic exchange, involving carbon, nitrogen, and sulfur sources as well as vitamins"

Central Bacterium Navigation For Epibiont Resources

COLONIZATION_FACILITATION

Source Taxon: Candidatus Symbiobacter mobilis central bacterium

Target Taxon: Chlorobium chlorochromatii CaD3 epibiont

Metabolites: hydrogen sulfide (CHEBI:16136)

Evidence

PMID:24267588 - SUPPORT (COMPUTATIONAL)

"can sense and move towards light and sulfide"

Possible Quinone-Mediated Electron Exchange

SYNTROPHY

Source Taxon: Chlorobium chlorochromatii CaD3 epibiont

Target Taxon: Candidatus Symbiobacter mobilis central bacterium

Biological Processes:

cellular respiration (GO:0045333)

Evidence

PMID:24267588 - SUPPORT (COMPUTATIONAL)

"electron cycling mechanisms, particularly those mediated by quinones"

Associated Datasets

Dataset	Type	Repository	Accession
Candidatus Symbiobacter mobilis genome Genome sequence for the central bacterium in Chlorochromatium aggregatum.	GENOME	OTHER	CP004885
Chlorobium chlorochromatii CaD3 genome Genome sequence for the green sulfur bacterial epibiont.	GENOME	OTHER	CP000108

Environmental Factors

Factor	Value	Unit
anoxic sulfide-reduced medium	Anaerobic sulfide-containing culture conditions	N/A
PMID:9446684 - SUPPORT (IN_VITRO) "maintained at high numbers in anoxic sulfide-reduced medium"
light and sulfide gradients	Light and sulfide are sensed by the central bacterium and used by the epibiont.	N/A
PMID:24267588 - SUPPORT (COMPUTATIONAL) "can sense and move towards light and sulfide"

Growth Media

anoxic sulfide-reduced enrichment medium

Atmosphere ANAEROBIC

Preparation notes: The consortium was enriched from eutrophic freshwater lake sediment and maintained in anoxic sulfide-reduced medium.

Evidence

PMID:9446684

"enriched from sediment samples of a eutrophic freshwater lake"