RAPID: A Matter of Life or Death: Identifying Factors That Regulate Susceptibility or Resistance of Bay Scallops to an Emergent Coccidian Parasite

The bay scallop, Argopecten irradians irradians, is one of the most economically and ecologically important species in coastal areas of New York State and the region. In summer/fall 2019, 90% of the scallops in eastern Long Island died, and this coincided with the emergence of an undescribed parasite that disrupts the kidney of infected animals. Genetic analysis showed that the parasite belongs to the Coccidia subclass of parasites, and this pathogen is now designated bay scallop Coccidia or BSC. This project will identify how BSC infects and kills scallops, and why some scallops are resistant to infection or death. Results from this study promotes the progress of science because research will identify mechanisms that regulate host-parasite interactions in scallops, and may help us understand how other Coccidia cause disease in economically important systems. It advances the national prosperity and the bioeconomy because results help scallop farmers and ecologists prevent or minimize death of this economically-important crop. This research will also provide tools to enable a broad research community working on apicomplexan parasites of invertebrates. This proposal also uses funding to train a post-doc, and graduate and undergraduate students to train the next generation of scientists. Results expected from this work will facilitate the recovery of bay scallops in New York waters, and will serve as a reference if BSC spreads to other coastal regions in the USA. Despite the common nature of Coccidia infection in invertebrates, very little is known about the biology of these microorganisms and the factors that regulate infection success. This RAPID will use an ongoing epizootic to generate information needed to characterize an ecologically- and economically-important member of the Coccidia that infects bay scallop (BSC). The study will use a combination of high-throughput sequencing techniques (genome and RNA sequencing), traditional cellular techniques (parasite purification, primary cell culture), and molecular biology methods to characterize BSC and probe the relationship between parasite life stages and scallop health; to evaluate how the disease will develop with the onset of summer conditions, conditions thought to be stressful to bay scallops; and to determine what genetic and environmental factors differentiate resistant scallops from susceptible ones. The new data are expected to solve an information gap that has been hampering the understanding of the mechanisms of survival and disease of BSCs in marine invertebrates. Moreover, the genetic information obtained from this work can be the basis for developing diagnostic tools to identify BSC infections and outbreaks in the future, which helps the bioecomony. This research will identify mechanisms that regulate host-parasite interactions in scallops, and may help us understand how other Coccidia cause disease in economically important systems. This research will also provide tools to enable a broad research community working on apicomplexan parasites of invertebrates. This award also uses funding to train a post-doc, and graduate and undergraduate students to train the next generation of STEM researchers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.