bacteria in sponges from the Red Sea
Pyrosequencing reveals highly diverse and species-specific microbial communities in sponges from the Red Sea
Marine sponges are associated with a remarkable array of microorganisms. Using a tag pyrosequencing technology, this study was the first to deeply investigate the microbial communities associated with three Red Sea sponges, Hyrtios erectus, Stylissa carteri, and Xestospongia testudinaria. We revealed highly diverse sponge-associated bacterial communities with up to 1,000 microbial OTUs and an estimate of up to 2,000 species. Altogether 26 bacterial phyla were detected from the Red Sea sponges, 11 of which were absent from the surrounding seawater and 4 of which were recorded in sponges for the first time. Up to 100 OTUs with an estimate of up to 300 archaeal species were revealed from a single sponge species. This is by far the highest diversity ever recorded for sponges. A non-negligible proportion of unclassified reads in sponges may represent the presence of novel species. Our results demonstrated that the sponge-associated microbial communities remained highly consistent in the same sponge species from different locations although they varied to certain degrees among different sponge species. A significant proportion of the tag sequences from the sponges could be assigned into one of the sponge-specific clusters previously defined. In addition, the sponge-associated microbial communities were consistently diverged from those in the surrounding seawater. Our results suggested the Red Sea sponges possess highly sponge-species specific microbial communities which are resistant to environmental influence. Although sponges have been regarded as microbial fermenters with a huge microbial diversity being reported among the animal kingdom, much of their microbial diversity remains to be explored.