V-ATPase subunit B plays essential roles in the molting process of the Chinese mitten crab, .

Vacuolar ATPase (V-ATPase) is a proton pump driven by ATP hydrolysis, and it plays an important role in numerous biological processes, such as protein degradation and synthesis, cell growth, and cell autophagy. The V-ATPase subunit B () is a conservative and regulatory subunit required for ATP hydrolysis during proton pumping. The of (), which includes an open reading frame (ORF) length of 1467 bp encoding 489 amino acids, was cloned to unveil the biological function of during the molting process of crustaceans. Spatial and temporal expression profiles showed that was highly expressed in the posterior gill accompanied with the highest osmotic pressure in the premolt (PrM) stage. Meanwhile, the highest expression level of was identified in the hepatopancreas and heart during the postmolt stage and epidermis in the intermolt stage, indicating that may perform diverse biological functions in different tissues during the molting process. The individual crabs in the interference group showed a high mortality rate (74%) and a low molting rate (26%) and failed to form a new epicuticle in the PrM stage. Meanwhile, a significant difference in osmotic pressure was identified between the interference and control groups. Our results indicate that is an indispensable functional gene that may participate in osmoregulation and help with the new epicuticle formation during the molting process of .