Expression analysis and response of Penaeus monodon 14-3-3 genes to salinity stress

Two isoforms of 14-3-3 protein, namely 14-3-3A and 14-3-3B, from the shrimp Penaeus monodon were investigated for their potential role in adaptation to salinity stress. Transcripts of 14-3-3A were found in various shrimp tissues whilst expression of 14-3-3B transcripts was more specific being observed in the osmoregulatory tissues, that is in the gills and epipodites. In shrimp gills, the 14-3-3A transcript levels slightly changed after transfer of the shrimp from 3 to 25 or to 40 ppt. In contrast, significant change in the mRNA levels in response to salinity stress was detected for 14-3-3B, where a significant decrease of 14-3-3B transcript was observed in gills of shrimp transferred from hypo-osmotic (3 ppt) salinity to iso-osmotic or hyper-osmotic (25 and 40 ppt, respectively) salinity. On the other hand, shrimp transferred from 40 ppt to 3 ppt showed a strong induction of 14-3-3B mRNA expression in the gills. These transcript expression analyses suggest that 14-3-3B is likely to be involved in the hyper-osmotic regulation in P. monodon. In addition, 14-3-3B appeared to regulate ATPase function since suppression of the gene by RNA interference resulted in a significant decrease in the total ATPase activity.