Meeting Abstract
The Eastern oyster Crassostrea virginica is an abundant benthic bivalve found throughout the Atlantic coast, including North Carolina. It is a remarkably resilient species found in intertidal and near-shore estuarine ecosystems. The environmental variation between estuarine, intertidal, and subtidal zones are ideal for studying ecological factors that can affect within species variation at local geographic scales. No data are currently available on combined genetic and physiological comparisons of oysters from geographically-close locations or from different habitats within locations to determine how genetic and environmental factors determine resilience in location-specific patterns. We investigated the contribution of genetic and environmental factors in stress tolerance among C.virginica subpopulations from 4 different sites: two estuarine, one subtidal, and intertidal. All studied populations were closely related and differ by less than 1% nucleotide diversity at COI. Basal expression of pattern recognition genes in oysters’ hemocytes (HCs) (TLR2,TLR3,TLR4 and Mannose Rec 2), as well as humoral and inflammation-related genes (Big defensin, Lysozyme, Complement system protein Cq3, and Tumor Necrosis Factor) showed a high level of divergence among all studied populations. Exposure to environmental hypoxia led to decrease in expression of all studied genes in HCs of oysters, where oysters from estuaries showed significantly elevated expression of TLR2, TLR4, and C3q. Expression of TLR3, TLR4, and Cq3 were elevated in HCs of oysters from intertidal zones under hypoxic conditions. Our results indicate that closely-related NC oysters have different mechanisms of acclimation to their specific habitats and response hypoxia.
