Myo-inositol oxygenase: A key player in the battle of Pacific white shrimp (Penaeus vannamei) against low-salinity stress

Salinity is an important physicochemical parameter in the aquatic environment that has a profound impact on the physiological processes of aquatic animals. Therefore, strong salinity adaptability is crucial for the survival of aquatic animals. This research investigated the physiological adaptation mechanisms of the economically significant aquaculture species Penaeus vannamei to low-salinity stress, with a focus on the myo-inositol metabolic pathway. This study cloned and identified the full-length cDNA sequence of Pv-miox, revealing its highest expression in the hepatopancreas and significant evolutionary conservation, potentially linked to salinity adaptation. Pv-miox dsRNA interference experiments revealed that shrimp mortality was reduced under acute low-salinity stress conditions. The main reason may be that reduced inositol metabolism leads to increased accumulation of myo-inositol in the gills, which alleviates the osmotic pressure imbalance of the body under low-salinity stress. Moreover, the oxidative stress, endoplasmic reticulum stress and inflammatory response caused by low-salinity stress are effectively regulated, avoiding excessive cell death. This study further clarifies the key role of myo-inositol metabolism in the adaptation of shrimp to low-salinity stress and helps to elucidate the physiological adaptation mechanism of crustaceans to low-salinity.