Phylogenetic Diversity of Bacteria Associated with the Marine Sponges, Spirastrella abata and Cinachyrella sp.

The bacterial community structure of two marine sponges, Spirastrella abata and Cinachyrella sp. collected from Jeju Island, in April 2009, was analyzed by 16S rDNA-denaturing gradient gel electrophoresis (DGGE). DGGE banding patterns indicated 8 and 7 bands for Spirastrella abata and Cinachyrella sp., respectively. Comparative sequence analysis of variable DGGE bands revealed from 92% to 100% similarity to the known published sequences. The bacterial groups associated with Spirastrella abata were Alphaproteobacteria and Deltaproteobacteria. The bacterial community of Cinachyrella sp. consisted of Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria. Alphaproteo-bacteria was common and predominant in both the sponge species. Deltaproteobacteria was found only in Spirastrella abata while Actinobacteria and Gammaproteobacteria were found only in Cinachyrella sp. The results revealed that though the common bacterial group was found in both the sponges, the bacterial community profiles differed between the two sponge species obtained from the same geographical location Keywords: 16S rDNA, bacterial diversity, DGGE, marine sponge, sponge-associated bacteria