Spatial and Species Variations in Bacterial Communities Associated with Corals from the Red Sea as Revealed by Pyrosequencing

Abstract

bMicrobial associations with corals are common and are most likely symbiotic, although their diversity and relationships with environmental factors and host species remain unclear. In this study, we adopted a 16S rRNA gene tag-pyrosequencing technique to investigate the bacterial communities associated with three stony Scleractinea and two soft Octocorallia corals from three locations in the Red Sea. Our results revealed highly diverse bacterial communities in the Red Sea corals, with more than 600 ribotypes detected and up to 1,000 species estimated from a single coral species. Altogether, 21 bacterial phyla were recovered from the corals, of which Gammaproteobacteria was the most dominant group, and Chloroflexi, Chlamydiae, and the candidate phylum WS3 were reported in corals for the first time. The associated bacterial communities varied greatly with location, where environmental conditions differed significantly. Corals from disturbed areas appeared to share more similar bacterial communities, but larger variations in community structures were observed between different coral species from pristine waters. Ordination methods identified salinity and depth as the most influential parameters affecting the abundance of Vibrio, Pseudoalteromonas, Serratia, Stenotrophomonas, Pseudomonas, and Achromobacter in the corals. On the other hand, bacteria such as Chloracidobacterium and Endozoicomonas were more sensitive to the coral species, suggesting that the host species type may be influential in the associated bacterial community, as well. The combined influences of the coral host and environmental factors on the associated microbial communities are discussed. This study represents the first comparative study using tag-pyrosequencing technology to investigate the bacterial communities in Red Sea corals.

Highly Heterogeneous Bacterial Communities Associated with the South China Sea Reef Corals Porites lutea, Galaxea fascicularis and Acropora millepora

“…Presently, the high-throughput pyrosequencing technique combined with barcoded PCR primers has been used for the survey of coral-associated bacterial communities by several researchers [10], [11], [15]–[19]. The number of OTUs detected in a single species of coral in the present study is similar to results obtained from Isopora palifera collected from Tan-Tzei Bay [11].…”

“…Therefore, the major limitation of these studies is that the characterization of the microbial communities is not comprehensive. More recently, pyrosequencing has been employed to investigate the bacterial community associated with corals [11], [15]–[19]. These studies have further supported the conclusion that the bacterial communities appear to be regulated by the host coral species.…”

The Shifts of Diazotrophic Communities in Spring and Summer Associated with Coral Galaxea astreata, Pavona decussata, and Porites lutea

“…Although high-throughput sequencing approaches are now commonly applied to investigate coral-associated microbial communities (Ceh et al, 2011; Chen et al, 2011; Lee et al, 2012; Mckew et al, 2012; Sunagawa et al, 2009), it has not been widely used to target nitrogen-fixing functional genes ( nifH ) to explore the coral-associated diazotrophic communities (Lema et al, 2014b). Compared with previous high-throughput sequencing studies on diazotrophic communities associated with the common Great Barrier Reef (GBR) coral Acropora millepora (Lema et al, 2014b), a much greater diversity of bacteria having the potential to fix nitrogen (possess the nifH gene) associated with G. astreata, Pavona decussata , and Porites lutea from Luhuitou fringing reef, South China Sea ( Table 1 ), and might be attributed to the differences in coral species.…”

Evolutionary Ecology of the Marine Roseobacter Clade

“…A few of them have been demonstrated to induce physiological changes in the host, both positive and negative, including gall disease in the red alga Prionitis lanceolata (98), juvenile oyster disease (99), infection of the red alga Delisea pulchra (100), and inhibition of the settlement of fouling organisms on the green alga Ulva australis (19). The most extensive research, however, has focused on associations with corals (101-107), as roseobacters can account for up to 50% of the coral mucus microbiome (108)(109)(110). It has been hypothesized that DMSP and dimethylsulfide (DMS) are the two compounds that structure the community of coral-associated microbes, since isolates from these populations are enriched with the ability to degrade DMSP/DMS (111).…”