Ruegeria sp. Strains Isolated from the Reef-Building Coral Galaxea fascicularis Inhibit Growth of the Temperature-Dependent Pathogen Vibrio coralliilyticus

Abstract

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.

A Zeaxanthin-Producing Bacterium Isolated from the Algal Phycosphere Protects Coral Endosymbionts from Environmental Stress

“…Recently, the beneficial roles of bacteria in the coral holobiont have been investigated (6). These functions include defense against pathogens (12,13) and the cycling of nutrients such as nitrogen (14) and sulfur (15). Moreover, coral-associated bacteria have been proposed to be involved in coral resistance to bleaching (16,17), which has a devastating impact on reefs worldwide (4).…”

Parasite-host ecology: the limited impacts of an intimate enemy on host microbiomes

“…typically have large genomes with highly versatile metabolic capabilities [ 54 ], and some have been shown to produce both algicidal and bactericidal compounds in culture. Indeed, cultures of coral-associated Ruegeria have been shown to inhibit growth of the coral pathogen Vibrio coralliilyticus [ 55 ]. While the vast majority of scar-associated ESVs are likely opportunists, these specific community members could be involved in limiting dysbiosis to the vicinity of the scar.…”

Shifts in marine invertebrate bacterial assemblages associated with tissue necrosis during a heatwave

“…Indeed, this genus is not only present in the core microbiome of healthy specimens O. patagonica, C. caespitosa and L. sarmentosa throughout the Mediterranean Sea, is also commonly associated with a large number of other coral species around the world (Huggett and Apprill, 2018; Rothing et al, 2020), even in larvae forms (Sharp et al, 2012; Zhou et al, 2017). It has been recently demonstrated that species belonging to this genus associated with corals show antibacterial activity against Vibrio coral pathogens (Miura et al, 2019) and provide essential vitamins like cobalamin (Karimi et al, 2019). Taken together, this OTU composed the core microbiome of geographically distant Anthozoans in the Mediterranean Sea and its abundance increased in necrotic tissues of their host under heat stress, highlighting the importance of this genus in marine invertebrate health during MHWs.…”