Community Shifts in the Surface Microbiomes of the Coral Porites astreoides with Unusual Lesions

Abstract

Apical lesions on Porites astreoides were characterized by the appearance of a thin yellow band, which was preceded by bleaching of the coral tissues and followed by a completely denuded coral skeleton, which often harbored secondary macroalgal colonizers. These characteristics have not been previously described in Porites and do not match common Caribbean coral diseases. The lesions were observed only in warmer months and at shallow depths on the fore reef in Belize. Analysis of the microbial community composition based on the V4 hypervariable region of 16S ribosomal RNA genes revealed that the surface microbiomes associated with nonsymptomatic corals were dominated by the members of the genus Endozoicomonas, consistent with other studies. Comparison of the microbiomes of nonsymptomatic and lesioned coral colonies sampled in July and September revealed two distinct groups, inconsistently related to the disease state of the coral, but showing some temporal signal. The loss of Endozoicomonas was characteristic of lesioned corals, which also harbored potential opportunistic pathogens such as Alternaria, Stenotrophomonas, and Achromobacter. The presence of lesions in P. astreoides coincided with a decrease in the relative abundance of Endozoicomonas, rather than the appearance of specific pathogenic taxa.

Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance

“…Furthermore, microbial communities associated with apical lesions on colonies of Belizean P. astreoides were found to be more diverse and harbored a significantly lower relative abundance of OTUs related to Endozoicomonas spp. than corals that did not appear to be lesioned (56). Lesioned colonies also demonstrated a higher relative abundance of Vibrionaceae than nonle-sioned colonies, similar to the present study.…”

Microbiome shifts and the inhibition of quorum sensing by Black Band Disease cyanobacteria

“…Dominance of Halomonas spp. in commensal coral microbiomes is consistent with observations in some other corals (McKew et al, 2012); however, the closely related genus Endozoicomonas tends to be dominant in others (Morrow et al, 2012;Bayer et al, 2013;Meyer et al, 2014).…”

On the Importance of the Microbiome and Pathobiome in Coral Health and Disease

“…Interestingly, Endozoicomonas sp. are known to have a transient part in their life cycle (Meyer et al, 2014) and the detection of this bacterium in the SML of the corals in Ainsworth et al's study is therefore not surprising. Furthermore, the SML has been shown to be a first line of defense for corals and therefore these microbes may still be playing a functional role of disease mitigation in the microbiome of this particular coral compartment.…”

“…For the full data set (OTU Table) same Endozoicomonas over large spatial scales, whilst Stylophora pistillata appear to harbor geographically distinct genotypes of Endozoicomonas (Neave et al, 2016). In addition, a study by Meyer et al (2014) highlighted that a reduction in abundance of these proposed endosymbionts correlated with an increase in abundances of opportunistic and potentially pathogenic bacteria associated with coral diseases. Endozoicomonas do indeed appear to be functionally important to corals, but it seems that the patterns are not universal (Ainsworth et al, 2015).…”

“…However, these terms are less widely used in the environmental sciences, and studies focused on Scleractinian corals for example have more commonly utilized the terms "microbiota" or "microbial associates" to describe the microbial communities associated with these hosts. Only recently has the term "microbiome" been used by the coral research community Kimes et al, 2013;Meyer et al, 2014) and to date, as far as we can tell, the concept of the pathobiome has not been used at all. Scleractinian corals add an extra level of complexity to the microbiome concept due to their symbiosis with algal communities (Symbiodinium sp.).…”