Diversity of symbiotic archaeal communities in marine sponges from Korea

A molecular analysis of archaeal communities in eight sponges collected along the coast of Cheju Island, Korea was conducted using terminal-restriction fragment length polymorphism (T-RFLP) in conjunction with sequencing analysis of 16S rDNA clones. The terminal-restriction fragment (T-RF) profiles showed that each sponge had a simple archaeal community represented by a single major peak of the same size except for one unidentified sponge (01CJ20). In order to identify the components of the community, 170 archaeal 16S rDNA clones were recovered from sponges and analyzed by RFLP typing. Sequences of 19 representative clones for all RFLP types found in each sponge were determined and phylogenetic analysis was carried out. Seventeen of these archaeal 16S rDNA clones showed a high similarity to marine group I, belonging to the crenarchaeotes. In the phylogenetic tree, 15 archaeal clones were grouped into five sponge-associated archaeal clusters. In the unidentified sponge sample (01CJ20), one major T-RF peak was represented by a single RFLP type (40 clones), which implied a specific relationship between the sponge and its symbiotic archaeal components.