SPECIFICITY OF SYMBIOTIC BACTERIA IN A TROPICAL MARINE SPONGE AXINELLA SP.

Abstract

Sponges (phylum Porifera) are one of the most ancient metazoans (more than 580 Myrs) that produce variety of natural chemicals. Many of those revealed to be produced by microorganisms inhabited in its cavity and sponge-associated microorganisms have been highlighted due to their potential. Recently host-archaeal phylotype specificity was reported from several species of the sponge genus Axinella but the specificity is not well known in case bacteria. In the present study analyzes of bacterial community associated with a marine sponge Axinella sp. collected at Weno Isl. Chuuk State, Federation State of Micronesia was conducted by T-RFLP (terminal-restriction fragment length polymorphism) and clonal analysis based on 16S rRNA gene sequences. Total 108 clones could be categorized into 14 different phylotypes under the boundary of 99% sequence similarity. Of them, 6 phylotypes including 74 clones affiliated into γ-Protebacteria (69.8% of the total clone libraries), 3 phylotypes with 19 clones into d-Protebacteria (17.9%), 2 phylotypes with 10 clones into a-Protebacteria (9.4%), 1 each into Bacteroidetes, Nitrospira and Fibrobacter. Total 16 T-RFs by tetrameric restriction enzyme HaeIII, HhaI or MspI obtained. The major T-RF by each enzyme originated from same phylotype belonging to γ-Protebacteria. The phylotype consist 53.8% of community and displaying high 16S rRNA gene sequence similarity with the clone B276_02a (EF092237) reported from Axinella corrugate (95.9%). This result implied that sponge host-bacterial phylotype specificity also existed in Axinella sp. [Supported by MEGRC & KORDI in house Program (PE98210)].