Effect of PoCD9 knockdown on bacterial infection. PoCD9.1-Ri, PoCD9.1-RiC, PoCD9.3-Ri, and PoCD9.3-RiC (RNAi control) were synthesized and transfected into FG cells, and the expression of PoCD9.1 and PoCD9.3 was determined by RT-qPCR (A, B). After transfection, the FGs were infected with Edwardsiella piscicida for 6 h, and the amounts of bacteria were determined (C, D). Control, the cells treated with PBS. Values are shown as the mean ± SEM (N = 3). N, the number of times the experiment was performed. *, P < 0.05; **, P < 0.01.