Disturbance to conserved bacterial communities in the cold-water gorgonian coralEunicella verrucosa

Abstract

The bacterial communities associated with healthy and diseased colonies of the cold-water gorgonian coral Eunicella verrucosa at three sites off the south-west coast of England were compared using denaturing gradient gel electrophoresis (DGGE) and clone libraries. Significant differences in community structure between healthy and diseased samples were discovered, as were differences in the level of disturbance to these communities at each site; this correlated with depth and sediment load. The majority of cloned sequences from healthy coral tissue affiliated with the Gammaproteobacteria. The stability of the bacterial community and dominance of specific genera found across visibly healthy colonies suggest the presence of a specific microbial community. Affiliations included a high proportion of Endozoicomonas sequences, which were most similar to sequences found in tropical corals. This genus has been found in a number of invertebrates and is suggested to have a role in coral health and in the metabolisation of dimethylsulfoniopropionate (DMSP) produced by zooxanthellae. However, screening of colonies for the presence of zooxanthellae produced a negative result. Diseased colonies showed a decrease in affiliated clones and an increase in clones related to potentially harmful/transient microorganisms but no increase in a particular pathogen. This study demonstrates that a better understanding of these bacterial communities, the factors that affect them and their role in coral health and disease will be of critical importance in predicting future threats to temperate gorgonian communities.

Differential specificity between closely related corals and abundant Endozoicomonas endosymbionts across global scales

“…These bacteria also frequently associate with other marine organisms, including gorgonians (Correa et al , 2013; La Rivière et al , 2013; Vezzulli et al , 2013; Bayer et al , 2013a; Ransome et al , 2014), ascidians (Dishaw et al , 2014), tube worms (Forget and Juniper, 2013), mollusks (Jensen et al , 2010; Hyun et al , 2014) and fish (Mendoza et al , 2013). Although the sequence-based evidence for Endozoicomonas as a core microbiome member of certain corals is compelling, most studies have used corals from only one geographic location and often methods across studies are not standardized, making comparative analyses difficult.…”

Spatial and Temporal Dynamics of Pacific Oyster Hemolymph Microbiota across Multiple Scales

“…Similar studies regarding host-associated microbiota are almost exclusively limited to humans, (e.g., Caporaso et al, 2011; David et al, 2014; DiGiulio et al, 2015), and a handful of model organisms (e.g., Fink et al, 2013; Marino et al, 2014). Whereas temporal patterns have been studied in non-model organisms, the focus remains on the population level and the sampling resolution usually coincides with significant host/environment-related shifts: developmental (e.g., Trabal et al, 2012; Hroncova et al, 2015), seasonal (e.g., Zurel et al, 2011; Bjork et al, 2013; Ransome et al, 2014) or abiotic disturbances (e.g., Vega Thurber et al, 2009; Wegner et al, 2013; Tracy et al, 2015). Longitudinal, individual-based, repeated-measure studies remain scarce (but see Pratte et al, 2015; Glasl et al, 2016).…”

“…Although marine sedentary organisms offer a good opportunity to examine factors and processes shaping dynamics of their associated microbiota over multiple spatial scales using spatially nested designs, this has not been done yet. Including a temporal component into such studies would further improve our understanding of natural microbial community dynamics (e.g., Fortunato et al, 2012; Ransome et al, 2014; Pierce et al, 2016) and thus refine the reference framework for evaluating disturbance effects.…”

Endozoicomonas genomes reveal functional adaptation and plasticity in bacterial strains symbiotically associated with diverse marine hosts

“…for review14). These bacteria associate with a wide variety of marine hosts, including corals1516171819, and other cnidarians2021, sponges2223, gorgonians242526, molluscs2728, worms29, fish3031, and tunicates3233. Despite these associations with numerous hosts in oceans worldwide, the functional role of Endozoicomonas remains unclear.…”

“…Despite these associations with numerous hosts in oceans worldwide, the functional role of Endozoicomonas remains unclear. Dimethylsulfoniopropionate (DMSP) breakdown has been suggested as a potential role2634, however, sequenced Endozoicomonas genomes lack DSMP metabolic pathways35. Endozoicomonas may also participate in a nutritional symbiosis, where the bacteria produce extracellular enzymes to degrade complex organic carbon sources that can then be used by the host25, as occurs with Oceanospirillales bacteria and deep-sea Osedax worms2.…”