Different resistance potential to reovirus in grass carp (Ctenopharyngodon idella) populations and their immune characteristics

Abstract

Our aim was to verify whether genes in the coagulation complement and cytokine interaction pathways are crucial to the resistance to grass carp hemorrhagic disease in grass carps (Ctenopharyngodon idella). To evaluate this, we acquired male grass carps with grass carp reovirus (GCRV) resistance, F1 generation, ordinary male fish, control F1 progenies (hybridized ordinary fish), and barbel chub (Squaliobarbus curriculus) as a positive control. We compared the expression variation of 13 immune factors in different tissues using real-time fluorescent quantitative PCR. Our results showed that the expression of the transforming growth factor-β3, nerve growth factor receptor, coagulation factor D, chemokine receptor XCR1, profibrinolysin, γ-globulin of complement component 1, complement component 2, and complement component 5 in the different tissues of the barbel chub were significantly higher than those in the grass carps populations under normal conditions. Except for a limited number of genes, their expression exhibited significant differences. There was no significant difference in these genes among grass carp populations with different GCRV resistance. These results indicate that the high gene expression in the coagulation complement and cytokine interaction pathways may be the main reason for the strong resistance of barbel chub to GCRV. However, high gene expression was not a factor affecting GCRV resistance between grass carp populations.