Ruegeria sp. Strains Isolated from the Reef-Building Coral Galaxea fascicularis Inhibit Growth of the Temperature-Dependent Pathogen Vibrio coralliilyticus
The coral microbiome has attracted increased attention because of its potential roles in host protection against deadly diseases. However, little is known about the role of coral-associated bacteria against the temperature-dependent opportunistic pathogen Vibrio coralliilyticus. In this study, we tested whether bacteria associated with the reef-building coral Galaxea fascicularis could inhibit the growth of V. coralliilyticus. Twenty-nine cultivable bacteria were successfully isolated from a healthy colony of G. fascicularis kept in an aquarium. Among the bacterial isolates, three Ruegeria sp. strains inhibited the growth of V. coralliilyticus P1 as a reference strain and Vibrio sp. isolated in this study. Ruegeria sp. strains were also detected from other G. fascicularis colonies in the aquarium and in previous field studies by 16S rRNA amplicon sequencing, suggesting that Ruegeria sp. strains are common among G. fascicularis colonies. These results illuminate the potential role of Ruegeria sp. in protecting corals against pathogenic Vibrio species.
KeywordsCoral-associated bacteria Ruegeria Vibrio coralliilyticus Antibacterial activity 16S rRNA amplicon sequencing
We thank Dr. Chuya Shinzato of the University of Tokyo for his fruitful discussions. This study was partially supported by JSPS Research Fellowships for Young Scientists (K.M., 17J07458, and S.A., 16J08791) and Postdoctoral Researchers (T.T., 17J05024), as well as Grant-in-aid for Young Scientists (KAKENHI) (T.T., 18K14479). This study was also partially supported by JST-CREST (N.M., W.A., M.U., JPMJCR16G2).
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