Molecular cloning, expression profiling of a carboxylesterase gene and its potential role in methyl farnesoate degradation in Eriocheir sinensis (Brachyura, Varunidae)

Abstract

In crustaceans, methyl farnesoate (MF) is an important sesquiterpenoid to regulate many physiological processes, especially reproduction and ovarian maturation. In this study, a 1919 bp cDNA of carboxylesterases (Es-CXE6) with some conserved motifs of the CXE multifunctional enzyme family was cloned from Eriocheir sinensis. Tissue and stage-specific expression results suggested that Es-CXE6 expression in hepatopancreas was highest and associated with the haemolymph MF titer. In vitro and in vivo experiments showed that Es-CXE6 expression was significantly upregulated by MF treatment in the hepatopancreas but not in the ovary. Furthermore, an eyestalk ablation experiment showed that Es-CXE6 expression was significantly upregulated on days 1 and 3 post eyestalk ablation in the hepatopancreas. Together, these results indicate that Es-CXE6 may degrade MF in the hepatopancreas in E. sinensis. Our results offer a potential approach to maintain the MF titer at appropriate levels, which has potential applications in crab aquaculture. In crustaceans, methyl farnesoate (MF) is an important sesquiterpenoid to regulate many physiological processes, especially reproduction and ovarian maturation. In this study, a 1919 bp cDNA of carboxylesterases (Es-CXE6) with some conserved motifs of the CXE multifunctional enzyme family was cloned from Eriocheir sinensis. Tissue and stage-specific expression results suggested that Es-CXE6 expression in hepatopancreas was highest and associated with the haemolymph MF titer. In vitro and in vivo experiments showed that Es-CXE6 expression was significantly upregulated by MF treatment in the hepatopancreas but not in the ovary. Furthermore, an eyestalk ablation experiment showed that Es-CXE6 expression was significantly upregulated on days 1 and 3 post eyestalk ablation in the hepatopancreas. Together, these results indicate that Es-CXE6 may degrade MF in the hepatopancreas in E. sinensis. Our results offer a potential approach to maintain the MF titer at appropriate levels, which has potential applications in crab aquaculture.