Meeting Abstract
Hemocytes (HCs) of marine bivalves are responsible for internal defense and shell repair. Oysters shell plays a role as a physical barrier, while immune system plays a role in protection of oysters from infections. Two congeners of oysters, Crassostrea gigas and Crassostrea virginica differ in their disease resistance and shell properties. C.gigas can resist a wide variety of diseases, but have a weak extracellular skeleton compared with the more disease-susceptible C. virginica. The physiological basis of the differential susceptibility to infections as well as shell hardness in these two closely related species remains unknown. We investigated transcriptomic profiles of immune-related and biomineralization genes in HCs, as well as the biomineralization genes in the mantle tissues of two oysters’ species. Pattern recognition genes (TLR2, TLR3, TLR4, mannose receptor and killer cell lectin receptor) as well as humoral and inflammation-related genes (Big defensin, complement system protein Cq3 and Tumor Necrosis Factor) were significantly higher expressed in HCs of C.gigas compared with C.virginica. Ion transport related genes (plasma membrane Ca2+ ATPase, NHX9 and NHE3) and genes encoding extracellular matrix proteins (silk-like protein, fibronectin 3-3 and fibronectin Ankyrin, casein kinases I and II) were highly expressed in C.virginica tissues except for chitin synthase III, fibronectin 3-2 and nacrein which were highly expressed in HCs of C.gigas compared to those of C.virginica. Our results indicate that functional specialization of HCs on the immune defense vs. biomineralization may contribute to differences in the disease resistance of the two oysters’ congeners. Supported by NSF IOS award 1557870.
