Name: Eric Schott

Email: schott@umbi.umd.edu

Author: Holly Bowers 1, Gretchen Messick 2, Ammar Hanif 1, Eric Schott 1

Author affiliation: 1) UMBI-Center of Marine Biotechnology, Baltimore, MD, USA 2) NOAA-NCCOS/Cooperative Oxford Lab, Oxford, MD, USA

Abstract title: Molecular Discovery of Crustacean RNA Viruses

Absstract:

The blue crab, Callinectes sapidus, is a portunid crab of major ecological and economic significance along the North and South American Atlantic coast. It is a trophic link between the benthic and the pelagic zones, and is the foundation of major fisheries on both continents. At least four morphological classes of viruses, three of which have RNA genomes, have been described in blue crab in association with disease for over 30 years. Captive crabs in soft-shell production facilities suffer mortality of 25% or more. We are taking a molecular/genomic approach to identifying RNA virus genomes in blue crabs that are under the extraordinary stress of captivity and molting. We have discovered that a reo-like virus (termed CsRV1) is associated with a majority of soft-shell crab mortalities. By isolation of dsRNA, we detected virus genomic RNA in over 60% of soft-shell mortalities, but only ~3% of healthy hard-shell crabs. Injection of viral preparations to naïve crabs results in the appearance of virus genomic dsRNA and death. To address major questions about the transmission and prevalence of this virus, which we term CsRV1, we cloned a segment of the RNA genome of the virus, and based on the 1.3 kb sequence, have developed an Rt-PCR-based assay. The dsRNA and PCR assays will facilitate studies of the CsRV1 in wild and captive populations of blue crab, and represent an important advance in understanding the role of this virus in natural mortality of blue crab. Using the same methodology that uncovered CsRV1, we have evidence for an additional 3 RNA virus genomes of uncertain taxonomic affiliation. Further investigations and genomic sequencing of these additional putative RNA genomes is planned, contingent upon resources.