Coral-Associated Viral Assemblages From the Central Red Sea Align With Host Species and Contribute to Holobiont Genetic Diversity

Abstract

Coral reefs are highly diverse marine ecosystems increasingly threatened on a global scale. The foundation species of reef ecosystems are stony corals that depend on their symbiotic microalgae and bacteria for aspects of their metabolism, immunity, and environmental adaptation. Conversely, the function of viruses in coral biology is less well understood, and we are missing an understanding of the diversity and function of coral viruses, particularly in understudied regions such as the Red Sea. Here we characterized coral-associated viruses using a large metagenomic and metatranscriptomic survey across 101 cnidarian samples from the central Red Sea. While DNA and RNA viral composition was different across coral hosts, biological traits such as coral life history strategy correlated with patterns of viral diversity. Coral holobionts were broadly associated with Mimiviridae and Phycodnaviridae that presumably infect protists and algal cells, respectively. Further, Myoviridae and Siphoviridae presumably target members of the bacterial phyla Actinobacteria, Firmicutes, and Proteobacteria, whereas Hepadnaviridae and Retroviridae might infect the coral host. Genes involved in bacterial virulence and auxiliary metabolic genes were common among the viral sequences, corroborating a contribution of viruses to the holobiont's genetic diversity. Our work provides a first insight into Red Sea coral DNA and RNA viral assemblages and reveals that viral diversity is consistent with global coral virome patterns.

A Review of Marine Viruses in Coral Ecosystem

“…Dicistroviridae was observed in the outgroup samples of Millepora platyphylla, Xenia sp., and Stylophora pistillata. Similar studies have revealed the relative abundances of Picobirnaviridae and Siphoviridae that were most accounted for in viromes of Galaxea fascicularis, Mycedium elephantotus, and Pachyseris speciosa when compared to Acropora cutherea, Pocillopora verrucosa, and Stylophora pistillata [141].…”

“…According to Cardenas et al [141], the viral community composition in Red Sea corals detected via metagenomic study included 97 viral families, which were found across meta-transcriptomics. The most abundant viral families were Siphoviridae, Mimiviridae and Retroviridae (dsDNA viral families) found in eukaryotes and bacteria, whereas ss-RNA viral families such as Qinviridae, Nyamiviridae and Solinviviridae were present in meta-transcriptome studies.…”

Contrasting heat stress response patterns of coral holobionts across the Red Sea suggest distinct mechanisms of thermal tolerance

“…At present, however, any presumptive functional consequences of these differences for coral holobiont physiology are unknown, despite it becoming broadly accepted that bacteria contribute to metaorganism biology and tness (McFall-Ngai et al 2013;Bang et al 2018;Rosado et al 2019;Pogoreutz et al 2020;Voolstra and Ziegler 2020). In cases of rapid environmental change, the role of the microbiome in supporting adaptation of the metaorganism may become even more pronounced, given that microbial-mediated change can be brought about through association with different microbes or exchange/incorporation of new genetic material (e.g., via horizontal gene transfer) and does not rely on mutation/recombination (Cárdenas et al 2020;Voolstra and Ziegler 2020).…”

Bacterial Communities Associated With Four Blooming Scyphozoan Jellyfish: Potential Species-Specific Consequences for Marine Organisms and Humans Health

“…The external and internal surfaces of marine animals are considered to be ubiquitously colonized by microorganisms ( Grossart and Tang, 2010 ). Microbial associations are often dominated by bacteria but co-inhabited by fungi, protozoa, archaea, and viruses ( Cárdenas et al, 2020 ; Deines et al, 2020 ). Microbial colonization of a certain surface is determined by the availability of nutrients, host immune responses, and competition between microbes from the surrounding environment for attachment space ( Wilson et al, 2011 ).…”