Abstract
Diseases of bivalves of aquacultural importance, including the valuable Australian silver-lipped pearl oyster (Pinctada maxima), have been increasing in frequency and severity. The bivalve microbiome is linked to health and disease dynamics, particularly in oysters, with putative pathogens within the Vibrio genus commonly implicated in oyster diseases. Previous studies have been biased toward the Pacific oyster because of its global dominance in oyster aquaculture, while much less is known about the microbiome of P. maxima. We sought to address this knowledge gap by characterizing the P. maxima bacterial community, and we hypothesized that bacterial community composition, and specifically the occurrence of Vibrio, will vary according to the sampled microenvironment. We also predicted that the inside shell swab bacterial composition could represent a source of microbial spillover biofilm into the solid pearl oyster tissues, thus providing a useful predictive sampling environment. We found that there was significant heterogeneity in bacterial composition between different pearl oyster tissues, which is consistent with patterns reported in other bivalve species and supports the hypothesis that each tissue type represents a unique microenvironment for bacterial colonization. We suggest that, based on the strong effect of tissue-type on the pearl oyster bacterial community, future studies should apply caution when attempting to compare microbial patterns from different locations, and when searching for disease agents. The lack of association with water at each farm also supported the unique nature of the microbial communities in oyster tissues. In contrast to the whole bacterial community, there was no significant difference in the Vibrio community among tissue types nor location. These results suggest that Vibrio species are shared among different pearl oyster tissues. In particular, the similarity between the haemolymph, inside shell and solid tissues, suggests that the haemolymph and inside shell environment is a source of microbial spillover into the oyster tissues, and a potentially useful tool for non-destructive routine disease testing and early warning surveillance. These data provide important foundational information for future studies identifying the factors that drive microbial assembly in a valuable aquaculture species.
Highlights
There is growing evidence that the microbial communities living in association with a diverse range of animal hosts significantly contribute to host behavior, physiology and health (McFall-Ngai et al, 2013; Raina et al, 2018)
Bacterial communities on the outside shell differed from most other tissues including the inside shell, while bacterial assemblages of the latter differed from the digestive tissue (P < 0.01 for all)
A triangle heat map of average intergroup Bray-Curtis similarities between tissue types illustrates that bacterial communities on the outside shell differed from most other tissues including the inside shell, and the bacterial communities within the large intestinal tissue had the most similar community structure across all replicates and both locations (Supplementary Figure 1)
Summary
There is growing evidence that the microbial communities living in association with a diverse range of animal hosts significantly contribute to host behavior, physiology and health (McFall-Ngai et al, 2013; Raina et al, 2018). Intestinal-associated microbial communities are commonly involved in nutrient mineralization and uptake for the host (Sonnenburg et al, 2004; Seth and Taga, 2014). Microbial communities contribute to important physiological processes including nutrient uptake and host defenses (Siboni et al, 2008; Glasl et al, 2016; Pita et al, 2018). There is a growing body of research that has linked microbiome composition to bivalve health and disease dynamics, within oysters (Trabal et al, 2012; Trabal Fernández et al, 2014). It has been proposed that characterizing and understanding shifts in the Vibrio population could be important for predicting disease events (King et al, 2019c)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
