Transcriptome Changes in Eriocheir sinensis Megalopae after Desalination Provide Insights into Osmoregulation and Stress Adaption in Larvae

Abstract

Eriocheir sinensis, an extremely invasive alien crab species, has important economic value in China. It encounters different salinities during its life cycle, and at the megalopal stage it faces a turning point regarding the salinity in its environment. We applied RNA sequencing to E. sinensis megalopae before (MB) and after (MA) desalination, resulting in the discovery of 21,042 unigenes and 908 differentially expressed genes (DEGs, 4.32% of the unigenes). The DEGs primarily belonged to the Gene Ontology groups “Energy metabolism,” “Oxidoreductase activity,” “Translation,” “Transport,” “Metabolism,” and “Stress response.” In total, 33 DEGs related to transport processes were found, including 12 proton pump genes, three ATP-binding cassettes (ABCs), 13 solute carrier (SLC) family members, two sweet sugar transporter (ST) family members and three other substance transporters. Mitochondrial genes as well as genes involved in the tricarboxylic acid cycle, glycolytic pathway, or β-oxidation pathway, which can generate energy in the form of ATP, were typically up-regulated in MA. 11 unigenes related to amino acid metabolism and a large number of genes related to protein synthesis were differentially expressed in MB and MA, indicating that E. sinensis possibly adjusts its concentration of free amino acid osmolytes for hyper-osmoregulation. Additionally, 33 salinity and oxidative stress induced genes were found to be differentially expressed, such as the LEA2, HSPs, GST and coagulation factor genes. Notably, LEA2 is an extremely hydrophilic protein that responds to desiccation and reported for the first time in crabs. Therefore, we suppose that when the environment is hypo-osmotic, the megalopae might compensate for ion loss via hyper-osmoregulation by consuming more energy, accompanied by a series of stress induced adaptions. This study provides the first genome-wide transcriptome analysis of E. sinensis megalopae for studying its osmoregulation and stress adaption mechanisms.

Identification and characterization of nascent polypeptide-associated complex alpha from Chinese mitten crab (Eriocheir sinensis): A novel stress and immune response gene in crustaceans

“…In consistent with our above observations, NACA also has been identified as one of the differentially expressed genes associated with salinity stress adaption in the megalopae of E. sinensis [22]. In addition, the up-regulated NACA expression was found in salinity stressed Arabidopsis [16].…”

The identification and characteristics of salinity-related microRNAs in gills of Portunus trituberculatus

“…The sodium-independent sulfate anion transporter and sodiumdependent phosphate transporter 1-B were involved in this process. Previous study showed that the two genes were also important osmoregulation factors in E. sinensis (Hui et al 2014). Peritrophins, which are tightly associated with the peritrophic membrane (PM) or chitin fibrils, were first isolated from insect PMs.…”

Molecular characterization and expression profile of three Fem-1 genes in Eriocheir sinensis provide a new insight into crab sex-determining mechanism

“…Few studies on this gene family have been performed in arthropod and it is unknown in crabs. The Fem-1 gene family was directly obtained from the different developmental stage transcriptomes of E. sinensis (Cui et al, 2013;Hui et al, 2014;Li et al, 2013Li et al, , 2014Song et al, 2015), which included three members EsFem-1a, EsFem-1b, and EsFem-1c. These three genes respectively encoded intracellular proteins of 640, 705, and 642 amino acids, which consisted of typical ankyrin repeat domains.…”