Meeting Abstract
Infectious diseases are a pervasive threat to marine populations and ecosystems. Identification of genes that contribute to variation in disease resistance is an essential step towards assessing the potential for disease resistance to evolve. Here we use case-control comparisons to screen variants of candidate disease-resistance genes of the blue crab, Callinectes sapidus for association with infection by pathogenic Vibrio spp. bacteria and the dinoflagellate Hematodinium perezi. Transcripts of candidate genes were identified by functional annotation of blue crab transcriptomes. Single nucleotide polymorphisms (SNPs) in ~200 of these candidate resistance genes were identified in alignments of transcripts from multiple individuals. Blue crabs from the coast of Louisiana were genotyped for these SNPs and tested for infection by pathogenic Vibrio bacteria and the dinoflagellate Hematodinium perezi with PCR-based assays. We then used latent factor mixed models to test for associations between SNPs and pathogens. Two SNPs were associated with infection by H. perezi, while 10 SNPs and 1 multi-SNP haplotype were associated with infection by Vibrio spp. Annotated biochemical functions for these candidate resistance genes include: ubiquitination, wound healing, signaling, lysosome function, and phagocytosis. Lastly, we identified correlations between resistant allele frequency and stressful environmental conditions in marshes throughout Louisiana and changes in resistant allele frequency among life stages (larvae, juvenile, and adult) that suggest the potential for selection at these candidate gene regions.
