Coral transcriptome and bacterial community profiles reveal distinct Yellow Band Disease states inOrbicella faveolata

Abstract

Coral diseases impact reefs globally. Although we continue to describe diseases, little is known about the etiology or progression of even the most common cases. To examine a spectrum of coral health and determine factors of disease progression we examined Orbicella faveolata exhibiting signs of Yellow Band Disease (YBD), a widespread condition in the Caribbean. We used a novel combined approach to assess three members of the coral holobiont: the coral-host, associated Symbiodinium algae, and bacteria. We profiled three conditions: (1) healthy-appearing colonies (HH), (2) healthy-appearing tissue on diseased colonies (HD), and (3) diseased lesion (DD). Restriction fragment length polymorphism analysis revealed health state-specific diversity in Symbiodinium clade associations. 16S ribosomal RNA gene microarrays (PhyloChips) and O. faveolata complimentary DNA microarrays revealed the bacterial community structure and host transcriptional response, respectively. A distinct bacterial community structure marked each health state. Diseased samples were associated with two to three times more bacterial diversity. HD samples had the highest bacterial richness, which included components associated with HH and DD, as well as additional unique families. The host transcriptome under YBD revealed a reduced cellular expression of defense-and metabolism-related processes, while the neighboring HD condition exhibited an intermediate expression profile. Although HD tissue appeared visibly healthy, the microbial communities and gene expression profiles were distinct. HD should be regarded as an additional (intermediate) state of disease, which is important for understanding the progression of YBD.

Microbiome shifts and the inhibition of quorum sensing by Black Band Disease cyanobacteria

“…BBD microbiomes were more diverse than healthy coral epibiomes; similarly, an increase in bacterial diversity was characteristic of other coral diseases (Sunagawa et al, 2009;Closek et al, 2014;Roder et al, 2014a). Even though α-diversity of BBD microbiomes was generally higher compared with that in coral commensal epibiomes, the same key members (R. reptotaeneum, Bacteroidales, Rhodobacteriaceae, Fusibacter spp.…”

Metatranscriptome analysis of the reef-building coral Orbicella faveolata indicates holobiont response to coral disease

“…But causation still remains elusive and few studies have addressed coral holobiont response to disease. Using a combination of 16S and cDNA microarrays, Closek et al (2014) found an increase in microbial diversity in Yellow Band Disease (YBD)-infected colonies and reduced expression of defense-and metabolism-related genes in the coral host Orbicella faveolata [formerly Monstastraea faveolata (Budd et al, 2012)]. …”

The pathogenBatrachochytrium dendrobatidisdisturbs the frog skin microbiome during a natural epidemic and experimental infection

“…Thus, the microbiome may play a role in disease resistance, or may itself be disturbed or altered by invading pathogens. Although a wealth of recent research has described associations between microbiome composition and a variety of syndromes in both humans and animals (16)(17)(18)(19)(20)(21)(22)(23)(24)(25), documentation of microbiome responses to natural epidemics of known infectious pathogens is rare.…”