A controlled aquarium system and approach to study the role of sponge-bacteria interactions using Aplysilla rosea and Vibrio natriegens

Mohammad F Mehbub,Stephen J Barnett,Jan Bekker,Wei Zhang,Jason E Tanner,Christopher M M Franco

doi:10.1038/s41598-018-30295-y

Mohammad F Mehbub, Stephen J Barnett + Show 4 more

Open Access

https://doi.org/10.1038/s41598-018-30295-y

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Abstract

Sponge-bacteria interactions are very important due to their ecological and biological significance. To understand the impact of interactions between sponges and bacteria (both associated with and external to sponges) on sponge-associated microbial diversity, sponge metabolite profiles and bioactivity, we used a controlled aquarium system and designed an experimental approach that allows the study of sponge-bacteria interactions in a well-defined manner. To test the feasibility of this approach, this system was used to study the interaction between a sponge Aplysilla rosea and a marine bacterium commonly found in seawater, Vibrio natriegens. Sponge explants were exposed to V. natriegens, at 5 × 106 cfu/ml, and changes were monitored for 48 hours. Pyro-sequencing revealed significant shifts in microbial communities associated with the sponges after 24 to 48 hours. Both the control (sponge only without added bacteria) and Vibrio-exposed sponges showed a distinct shift in bacterial diversity and abundance with time. Vibrio exposure significantly increased bacterial diversity, the abundance of a number of taxa compared to control sponges. The result experimentally supports the notion of dynamic and concerted responses by the sponge when interacting with a bacterium, and demonstrates the feasibility of using this controlled aquarium system for the study of sponge-bacteria interactions.

Highlights

Sponges host a distinct and diverse microbial community of symbiotic bacteria, archaea and unicellular eukaryotes[1]
Large pieces (>10 cm) of A. rosea were successfully maintained in recirculating aquarium systems (100 L) for up to 40 days with feeding and regular seawater exchange
We demonstrated, using pyrosequencing, that this microbial community change can occur within 24 hours (Fig. 2)

Summary

Introduction

Sponges (phylum Porifera) host a distinct and diverse microbial community of symbiotic bacteria, archaea and unicellular eukaryotes[1]. An understanding of the ecology and functional diversity of marine symbionts associated with sponges and how they interact to produce bioactive metabolites could lead to the development of production strategies for the drug leads from sponge sources[18,19,20]. It was found that the interaction between the sponge and Streptomyces ACT-52A played an important role in regulating secondary metabolite production This approach has not been used to understand the interactions between sponges and external foreign bacteria, such as the common marine bacterium Vibrio natriegens[23] used in this study. Based on our recent study[22], we hypothesized that the interactions between a sponge and the external foreign bacteria in its surrounding environment, could play an important and different role as compared to its associated bacteria in changing the sponge microbial diversity, morphology and bioactivity. We selected this bacterium because it has not been identified as associated with A. rosea, grows in the marine environment[23], and has a very short generation time of less than 10 min under optimal growth conditions[33]

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