Identification of differentially expressed genes in large yellow croaker (Pseudosciaena crocea) induced by attenuated live Vibrio anguillarum

Vibrio angillarum is an important pathogen for large yellow croaker, being responsible for significant economic losses in Chinese aquaculture. Gene expression was studied in large yellow croaker stimulated with an attenuated live V. anguillarum MVAV6203. Subtractive cDNA libraries were constructed by suppression subtractive hybridization (SSH) from 3 immune-relevant tissues during the process. Approximately 216 clones were sequenced from the library, giving a total of 179 different expressed sequence tags (ESTs), which were further identified and annotated by comparing with the existing genes in GenBank. These identified ESTs represented at least 39 different genes which are involved in immune system, cell communication, protein regulation and other processes, most of which are not previously reported in large yellow croaker. Expression of 4 selected genes encoding complement component inhibitor 1, hepcidin, α-NAC and coagulation factor II in liver, spleen and head kidney of the fish was further studied by real-time quantitative PCR to verify their differential expression as a result of induction. A clear increase in expression in liver and head kidney of the fish between challenged and control samples was observed for genes encoding complement component inhibitor 1 and hepcidin, which seems to play an important role in immune system of fishes.