Sponges harbor a remarkable diversity of microbial symbionts where signal molecules can accumulate and enable cell-cell communication, such as quorum sensing (QS). Bacteria capable of QS were isolated from marine sponges, however an extremely small fraction of the sponge microbiome is amenable to cultivation. We took advantage of community genome assembly and binning to investigate the uncultured majority of sponge symbionts. We identified a complete AHL-QS systems (designated TswIR) and seven partial luxI homologues in the microbiome of Theonella swinhoei. The TswIR system was novel and shown to be associated with an alphaproteobacterium of the Rhodobacterales order, here termed Rhodobacterales bacterium TS309. The tswI gene when expressed in E. coli produced three AHLs, of which two were also identified in T. swinhoei sponge extract. The taxonomic affiliation of the 16S rRNA of Rhodobacterales bacterium TS309 to a sponge-coral specific clade, its enrichment in sponge versus seawater and marine sediment samples, combined with the presence of sponge-specific features such as ankyrin-like domains and tetratricopeptide repeats, indicate a likely symbiotic nature of this bacterium.

A NEW N-ACYL HOMOSERINE LACTONE SYNTHASE IN AN UNCULTURED SYMBIONT OF THE RED SEA SPONGE THEONELLA SWINHOEI

TETA, ROBERTA;COSTANTINO, VALERIA;
2016

Abstract

Sponges harbor a remarkable diversity of microbial symbionts where signal molecules can accumulate and enable cell-cell communication, such as quorum sensing (QS). Bacteria capable of QS were isolated from marine sponges, however an extremely small fraction of the sponge microbiome is amenable to cultivation. We took advantage of community genome assembly and binning to investigate the uncultured majority of sponge symbionts. We identified a complete AHL-QS systems (designated TswIR) and seven partial luxI homologues in the microbiome of Theonella swinhoei. The TswIR system was novel and shown to be associated with an alphaproteobacterium of the Rhodobacterales order, here termed Rhodobacterales bacterium TS309. The tswI gene when expressed in E. coli produced three AHLs, of which two were also identified in T. swinhoei sponge extract. The taxonomic affiliation of the 16S rRNA of Rhodobacterales bacterium TS309 to a sponge-coral specific clade, its enrichment in sponge versus seawater and marine sediment samples, combined with the presence of sponge-specific features such as ankyrin-like domains and tetratricopeptide repeats, indicate a likely symbiotic nature of this bacterium.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/621081
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