Cloning and expression of three small heat shock proteins in Cherax quadricarinatus under Vibrio alginolyticus or Aeromonas hydrophila stress

Abstract

Cherax quadricarinatus has been widely introduced and cultured around the world and has been seriously affected by pathogens, including viruses and bacteria. Small heat shock proteins (sHsps) have been shown to have a positive effect on immune responses in animals. In this study, three subunits of sHsps (CqsHsps, named CqHsp24.06, CqHsp41.97 and CqHsp40.17) from C. quadricarinatus were cloned. The coding sequence lengths of the CqHsp24.06, CqHsp41.97 and CqHsp40.17 genes were 654 bp, 1128 bp and 1074 bp, with a molecular weight of 24.06, 41.97 and 40.17 kDa, respectively. In normal tissues, the expression level of CqHsp24.06 was the highest in the intestinal tract and was 12 times higher than that in the hepatopancreas, while CqHsp41.97 was mostly expressed in the gills which was 8 times higher than that in the nerves. However, CqHsp40.17 was highest in the nerves and was 12 times higher than its expression level in the gonads. In gills of C. quadricarinatus stressed by Vibrio Alginolyticus, the relative expression levels of CqHsp24.06, CqHsp41.97 and CqHsp40.17 in gill first increased and then decreased, and the maximum expression increased by 25 times. Under Aeromonas hydrophila stress, the expression of CqHsp24.06 and CqHsp41.97 reached the highest level at the 3-h time point and at the 12-h time point for CqHsp40.17, and the maximum expression increased by 3.5 times. These results indicated that CqsHsps could induce the activation of the immune system, and they were more sensitive to Vibrio Alginolyticus than to Aeromonas hydrophila.