The expression of prophenoloxidase mRNA in red swamp crayfish, Procambarus clarkii, when it was challenged

The expression of the prophenoloxidase (proPO) gene was investigated in nine tissues of red swamp crayfish Procambarus clarkii, by real-time PCR after challenges by CpG oligodeoxynucleotide (ODN), Aeromonas hydrophila and white spot syndrome virus (WSSV). The results can be summarized as follows: (i) the expression level of the proPO gene in haemocytes was highest among nine studied tissues before the challenge; (ii) the expression of proPO increased in all studied tissues after stimulation by CpG ODN and WSSV, and also increased in all tissues, except the ovary, after the A. hydrophila challenge; (iii) the whole expression profiles were different, suggesting that different immune mechanisms may exist for crayfish that are resistant to WSSV and A. hydrophila, although the expression in haemocytes was similar before and after the WSSV and A. hydrophila challenges.

► The proPO gene was expressed highest in haemocytes.
► The proPO expression increased in all studied tissues after CpG ODN challenge.
► The proPO expression decreased in ovary after injection of A. hydrophila.
► The proPO expression in haemocytes is similar after WSSV and A. hydrophila injection.