RNAi-mediated knockdown of the aquaporin 4 gene impairs salinity tolerance and delays the molting process in Pacific white shrimp, Litopenaeus vannamei

The objective of this study was to investigate the function of the aquaporin 4 gene (LvAQP4), which had previously been characterized in Pacific white shrimp, Litopenaeus vannamei. To achieve this, double -stranded RNA (dsRNA) targeting LvAQP4 was synthesized and injected into shrimp, resulting in a significant reduction in the expression of LvAQP4. Subsequent to the evaluation of the impact of LvAQP4 transcriptional silencing on shrimp under salinity challenges, we observed that the downregulation of LvAQP4 expression in the gills resulted in the downregulation of aquaglyceroporin (LvAQP3) and unorthodox aquaporin (LvAQP11) genes, as well as ion transporter genes, such as LvNKA alpha, LvNKA beta, LvCAc, and LvVHA-a. Notably, the inhibition of LvAQP4 had a significant impact on the expression patterns of these osmoregulatory genes, particularly during periods of high salinity stress. Furthermore, there was a notable increase in the mortality rate of shrimp under high -salinity stress. Moreover, the suppression of LvAQP4 through RNA interference led to a significant delay in the molting rate of shrimp. Furthermore, it resulted in an increase in the expression of LvMIH and a significant reduction in key genes involved in the ecdysone signaling pathway, including LvEcR, LvRXR, and LvE75. These findings suggest that LvAQP4 may play a regulatory role in the molting process of shrimp by modulating MIH and the ecdysone signaling pathway. Moreover, this study lays the groundwork for future investigations into the functions of aquaporins in shrimp osmoregulation and growth, contributing to an enhanced understanding of these essential regulatory mechanisms.