title: Genomic analysis reveals versatile heterotrophic capacity of a potentially symbiotic sulfur-oxidizing bacterium in sponge.
abstract: Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body.
authors.affiliation: Divison of Life Science, Hong Kong University of Science and Technology, Hong Kong.
authors.forename: Ren-Mao
authors.initials: RM
authors.lastname: Tian
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Salim
authors.initials: S
authors.lastname: Bougouffa
authors.forename: Zhao-Ming
authors.initials: ZM
authors.lastname: Gao
authors.forename: Lin
authors.initials: L
authors.lastname: Cai
authors.forename: Vladimir
authors.initials: V
authors.lastname: Bajic
authors.forename: Pei-Yuan
authors.initials: PY
authors.lastname: Qian
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D020563:Gammaproteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016680:Genome, Bacterial; D023281:Genomics; D052836:Heterotrophic Processes / Q000235:genetics*; D010084:Oxidation-Reduction; D010802:Phylogeny; D011161:Porifera / Q000382:microbiology*; D013455:Sulfur / Q000378:metabolism*; D013559:Symbiosis
chemical_list: D013455:Sulfur