Corallivory and the microbial debacle in two branching scleractinians.

The grazing activity by specific marine organisms represents a growing threat to the survival of many scleractinian species. For example, the recent proliferation of the corallivorous gastropod Drupella now constitutes a critical case in all South-East Asian waters. If the damaging effects caused by this marine snail on coral polyps are relatively well known, the indirect incidence of predation on coral microbial associates is still obscure and might also potentially impair coral health. In this study, we compared the main ecological traits of coral-associated bacterial and viral communities living in the mucus layer of Acropora formosa and Acropora millepora, of healthy and predated individuals (i.e., colonized by Drupella rugosa), in the Bay of Van Phong (Vietnam). Our results show a substantial impact of the gastropod on a variety of microbiological markers. Colonized corals harbored much more abundant and active epibiotic bacteria whose community composition shifted toward more pathogenic taxa (belonging to the Vibrionales, Clostridiales, Campylobacterales, and Alteromonadales orders), together with their specific phages. Viral epibionts were also greatly influenced by Drupella corallivory with spectacular modifications in their concentrations, life strategies, genotype richness, and diversity. Novel and abundant circular Rep-encoding ssDNA viruses (CRESS-DNA viruses) were detected and characterized in grazed corals and we propose that their occurrence may serve as indicator of the coral health status. Finally, our results reveal that corallivory can cause severe dysbiosis by altering virus-bacteria interactions in the mucus layer, and ultimately favoring the development of local opportunistic infections.

Non-contiguous finished genome sequence and description of Halopiger goleamassiliensis sp. nov.

Halopiger goleamassiliensis strain IIH3(T) sp. nov. is a novel, extremely halophilic archaeon within the genus Halopiger. This strain was isolated from an evaporitic sediment in El Golea Lake, Ghardaïa region (Algeria). The type strain is strain IIH3(T). H. goleamassiliensis is moderately thermophilic, neutrophilic, non-motile and coccus-shaped. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,906,923 bp long genome contains 3,854 protein-encoding genes and 49 RNA genes (1 gene is 16S rRNA, 1 gene is 23S rRNA, 3 genes are 5S rRNA, and 44 are tRNA genes).