Comparative Functional Analysis Reveals Conserved Roles of Aquaporins Under Osmotic Dehydration in Steinernema carpocapsae Strains.

Entomopathogenic nematodes (EPNs), including Steinernema and Heterorhabditis, are obligate insect parasites widely used in biological pest control. However, their efficacy is often limited by susceptibility to environmental stresses like desiccation. Aquaporins (AQPs), channel proteins facilitating water and solute movement across membranes, are hypothesized to play a key role in the osmotic stress response of EPNs. This study identified and cloned three AQP genes (L596_g7661, L596_g18121, and XLOC_007750) from four strains of Steinernema carpocapsae. Bioinformatic analysis confirmed that these AQPs belong to the aquaglyceroporin subfamily and share high sequence homology across strains. Functional characterization in Xenopus oocytes demonstrated that AQP L596_g7661 facilitates glycerol transport. Expression patterns under osmotic dehydration revealed significant upregulation of L596_g7661 and XLOC_007750 in all strains, while L596_g18121 expression remained unchanged. These findings indicate that specific AQPs are involved in the molecular response of S. carpocapsae to osmotic stress, providing crucial insights for breeding resilient EPN strains and enhancing their field application.