Trehalose metabolism in the Chinese mitten crab Eriocheir sinensis: Molecular cloning of trehalase and its expression during temperature stress
Jie Bao, Xiaohan Wang, Chengcheng Feng, Xiaodong Li, Hongbo Jiang
Abstract
Trehalose, a nonreducing disaccharide, serves as the principal hemolymph sugar involved in energy metabolism and protection against stress in crustaceans. While there have been recent advances in understanding of trehalose biosynthesis in crustaceans, the catabolism of trehalose remains poorly understood. Trehalase catalyzes the hydrolysis of trehalose into glucose and plays a crucial physiological role in most organisms. In this study, we isolated and characterized a trehalase gene, EsTreh, in the Chinese mitten crab Eriocheir sinensis. The full-length EsTreh cDNA sequence was 2488 bp with an open reading frame (ORF) of 1914 bp encoding a protein of 638 amino acids with a deduced molecular weight of 73.53 kDa and a pI of 6.10. The Es-Treh protein contains signature motifs 1 and 2. The transcript levels of EsTreh were significantly inhibited after 24 h of heat and cold stress in E. sinensis. The trehalose content was maintained during 12 h of cold and heat stress, but increased significantly after 24 h of stress. The glucose and lactic acid contents showed a trend of initial rapid increase followed by an extended decline. The glycogen content significantly decreased with the extension of thermal stress. Our study provided the first description of trehalase in crustaceans and demonstrated that trehalase contributes to the accumulation of trehalose during thermal stress. Our findings suggest that the glycogenolysis and gluconeogenesis pathways might be involved in the transformation of glycogen and lactic acid to trehalose.