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

## TL;DR

This study explores how aquaporins help Steinernema carpocapsae nematodes survive osmotic stress, offering insights for improving biological pest control.

## Contribution

The study identifies and functionally characterizes aquaporins involved in osmotic stress response in Steinernema carpocapsae.

## Key findings

- Three aquaporin genes were cloned and confirmed to belong to the aquaglyceroporin subfamily.
- L596_g7661 facilitates glycerol transport and is upregulated under osmotic dehydration.
- XLOC_007750 is also upregulated, while L596_g18121 expression remains unchanged.

## Abstract

This study investigated the role of aquaporins (AQPs) in the osmotic stress response of the entomopathogenic nematode Steinernema carpocapsae. Three AQP genes (L596_g7661, L596_g18121, and XLOC_007750) were cloned from four different S. carpocapsae strains. Bioinformatic analysis confirmed they belong to the aquaglyceroporin subfamily. Functional assay in Xenopus oocytes demonstrated that the AQP L596_g7661 facilitates glycerol transport. Under osmotic dehydration, the expressions of L596_g7661 and XLOC_007750 were significantly upregulated across all strains, while L596_g18121 expression remained unchanged. The findings reveal that specific aquaglyceroporins are involved in the molecular adaptation of S. carpocapsae to osmotic stress. This research provides a theoretical basis for identifying key stress-tolerance genes and contributes to the future breeding of resilient nematode strains for more reliable biological pest control.

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.