News and Events

Seminar

Stressor Induced Metabolic Shifts Drive Pathogenesis in the Coral Microbiome

Dr Rebecca Vega Thurber, Florida International University

Where: ARC Centre of Excellence Conference Room, JCU. Video-linked to Centre for Marine Studies, UQ.

When: Monday 25 August, 1:00 pm

Dr Vega Thurber received her PhD from Stanford University California in 2005 where her research investigated Sea urchin Embryogenesis and cell biology. She currently starting her own laboratory at the Florida International University, where her research investigates the viral ecology of corals and coral reef habitats. This continues her previous research as an NSF postdoctoral fellow at San Diego State University in the laboratory of Professor Forest Rowher.

ABSTRACT:

The holobiont is the community of metazoans, protists, and microbes associated with scleratinian corals. Disruptions in these associations have been correlated with coral disease, but little is currently known about the series of events involved in the shift from symbiosis to pathogenesis. To evaluate the structural and functional alterations of microbial communities on coral, Porites compressa was experimentally exposed to four stressors known and hypothesized to reduce coral abundance, specifically: increased temperature, elevated nutrients, dissolved organic carbon loading, and reduced pH. Microbial metagenomic samples were collected across 64 hours of treatment and compared using 454 Life Sciences pyrosequencing. Functional gene analysis demonstrated that stressors increased the abundance of microbial genes involved in pathogenesis and stress resistance, sulfur and nitrogen metabolism, motility and chemotaxis, fatty acid and lipid utilization, and secondary metabolism. However, the specific mechanisms by which these metabolisms changed were unique in each treatment. Taxonomically annotated protein encoding sequences also demonstrated that the structure of coral-associated microbiomes (both prokaryotic and eukaryotic) shifted from a healthy-associated coral community to a disease-associated community. A combination of these analyzes showed that thermal stress caused a concomitant loss of the symbiotic zooxanthella Symbiodinium and elevation of Fungi and Vibrio species. These Vibrio sequences were in low abundance, but were almost entirely responsible for the metabolic shifts identified in the thermally treated coral microbes. Therefore, a numerically small component of the microbiome was found to significantly alter holobiont metabolism to become highly mobile, virulent, and host evasive during stress. These data suggest that the metabolic contribution of a just a few members of a community can profoundly shift the health status of an entire system.