Pyrosequencing revealed shifts of prokaryotic communities between healthy and disease-like tissues of the Red Sea spongeCrella cyathophora

Abstract

Sponge diseases have been widely reported, yet the causal factors and major pathogenic microbes remain elusive. In this study, two individuals of the sponge Crella cyathophora in total that showed similar disease-like characteristics were collected from two different locations along the Red Sea coast separated by more than 30 kilometers. The disease-like parts of the two individuals were both covered by green surfaces, and the body size was much smaller compared with adjacent healthy regions. Here, using high-throughput pyrosequencing technology, we investigated the prokaryotic communities in healthy and disease-like sponge tissues as well as adjacent seawater. Microbes in healthy tissues belonged mainly to the Proteobacteria, Cyanobacteria and Bacteroidetes, and were much more diverse at the phylum level than reported previously. Interestingly, the disease-like tissues from the two sponge individuals underwent shifts of prokaryotic communities and were both enriched with a novel clade affiliated with the phylum Verrucomicrobia, implying its intimate connection with the disease-like Red Sea sponge C. cyathophora. Enrichment of the phylum Verrucomicrobia was also considered to be correlated with the presence of algae assemblages forming the green surface of the disease-like sponge tissues. This finding represents an interesting case of sponge disease and is valuable for further study.

Metagenomic studies of the Red Sea

“…The unusual high tolerance of Theonella swinhoei to arsenate and arsenite, for example, is attributed to its microbiome(Keren et al, 2015). Gao et al(Gao et al, 2014a;Gao et al, 2015) examined the microbial diversity of healthy vs. diseased sponges collected from the Red Sea and reported a drastic shift in microbiome of abnormal sponge tissue. While the healthy sponge tissue showed a lower microbial diversity, the diseased tissue demonstrated a dramatic increase in microbial diversity with a decrease in sponge-specific microbial communities.…”

Mass disease and mortality of Baikal sponges

“…To identify the causes of infection, 16S RNA sequencing of sponge symbionts (Webster et al, 2002;Cervino et al, 2006;Angermeier et al, 2011;Stabili et al, 2012;Choudhury et al, 2015;Gao et al, 2015;Sweet et al, 2015;Blanquer et al, 2016), amplicon sequencing of other genome sites of bacteria and eukaryotes (Choudhury et al, 2015;Sweet et al, 2015), whole genome sequencing of a bacterial pathogen (Choudhury et al, 2014), and culturing of pathogenic bacteria (Stabili et al, 2012;Choudhury et al, 2015) were used in these studies. The significant changes in the composition of the microbiome were observed in all cases of sponge disease described.…”

“…In most cases, researchers only state dysbiosis, i.e. a shift in the microbial community of diseased sponges, without isolating a pathogenic agent (Webster et al, 2008;Gao et al, 2015;Blanquer et al, 2016;Luter et al, 2017;Deignan et al, 2018).…”

Molecular and Functional Ecology of Sponges and Their Microbial Symbionts

“…Thus, disease in this case would not be caused by the presence of a single pathogen, but rather a subtle shift in the microbiome may have resulted in host sickness, which is reminiscent of the balance between health and disease for hosts in gut symbioses relying on the activities of members of the entire microbial symbiont community (e.g., Mazmanian et al 2008). Indeed, Gao et al (2015) recently demonstrated shifts of prokaryotic communities between healthy and disease-like sponge tissues. Thus, Koch's postulates may not apply to some climate-change-instigated diseases of the future, and results like those described above highlight the concerns that many have about a warming ocean that is experiencing shifts in general chemistry (e.g., Luter et al 2010;Olson et al 2014;Sweet et al 2015).…”