Advances in Understanding Large Yellow Croaker Iridovirus and Host Immune Responses

ABSTRACT The large yellow croaker has experienced significant declines in wild stocks, while its populations have been replenished through diverse aquaculture systems, making it currently the most cultivated marine fish in China. The large yellow croaker farming industry has suffered greatly from bacterial and viral diseases. Given the economic importance of this species, extensive studies have been conducted on its genome and immune responses. Large yellow croaker iridovirus (LYCIV) is a major pathogen of this species, and the innate immune response constitutes the primary line of defense. Drawing on the broad understanding of innate immune responses of the large yellow croaker and other marine fishes to bacterial and viral infections, this review summarizes recent progress in characterizing the LYCIV genome and pathogenicity, as well as the host immune response to LYCIV infection or to simulated viral challenge with poly(I:C), through analysis of the functions of key molecular players. In addition, molecular breeding approaches assisted by genomic selection and genome editing, together with immunological prevention through vaccination, are discussed with respect to their application and development for combating LYCIV in the large yellow croaker. Overall, this review aims to provide an integrated perspective on the innate immunity and vaccination of the large yellow croaker to support the development of disease resistance.