Wednesday 21 October 2015

Title: “The Microbiome of Asteroids Affected by Sea Star Wasting Disease”

Speaker:
Dr. Ian Hewson, Cornell University

Abstract:
Beginning in June 2013 and continuing to present, sea star wasting disease (SSWD) has affected a large number of asteroids on the US Pacific Coast, from the Kenai Peninsula (Alaska) to Baja California. The disease has affected over 18 species of sea stars, spanning much of the asteroid phylogeny, and is not consistently accounted for by large scale ocean changes (e.g. El Nino) or environmental pollutants. Work performed in 2013 to 2014 highlighted that the disease is associated with a novel, transmissible densovirus (Parvoviridae), and that virus-sized particles caused disease signs – the Sea Star associated Densovirus (SSaDV). Transcriptomic analyses identified that SSWD is accompanied by elevated apoptotic and tissue remodeling functions consistent with disease signs. Remaining eukaryl, bacterial and archaeal components of the microbiome did not change in composition with disease signs, but the overall abundance of bacteria increased when asteroids were affected by SSWD. However, screening of historical specimens identified the presence of SSaDV in asteroid populations as long ago as 1942, and it has also been detected in several species of non-asteroid echinoderms. Current research focuses on understanding the transmission of SSaDV, microbiome and host transcription over time courses of sign development, and genome-genome comparison of SSaDV through time, across the geographic range of the disease, and between species, which will facilitate understanding of its potentially altered pathogenicity.

Host: Dr. Coleen Burge, Ph.D.