The effects of soil salinity and wheat curl mite infestation on the antioxidative response of barley

Abstract

Background and Aims Climate changes profoundly influence the level of stress that plants experience. This study was conducted to investigate the redox homeostasis of barley in response to salinity, infestation by Aceria tosichella Keifer. (the wheat curl mite, WCM), and the combined effects of these stress factors. Methods Hordeum vulgare L. plants were treated with sodium chloride at concentrations of 50 mM and 100 mM and were inoculated with WCM. The plants were also exposed to both stressors simultaneously. Biochemical and molecular parameters were measured to evaluate the potential role of reactive oxygen species (ROS) in modulating barley’s response. Results The analysis of ROS and antioxidant levels revealed distinct patterns based on specific stress factors. Hydrogen peroxide levels increased in all treatments, indicating a plant redox imbalance. In contrast, superoxide anion levels rose only with WCM infestation, suggesting a specific response to this pest. Lipid peroxidation decreased with WCM inoculated combinations. Conversely, carbonyl group content increased with NaCl and combined stresses but declined with WCM. Variations in ascorbic acid to dehydroascorbic acid and reduced to oxidized glutathione ratios suggest complex regulation of antioxidant metabolism. Moreover, significant changes in the activities and gene expression of key enzymes, including catalases, peroxidases, and superoxide dismutases, highlight the critical role of antioxidant mechanisms in plant responses to stress. Conclusion Our research results indicate that the response of barley to a combination of stress factors, such as salinity and WCM, differs significantly from the responses induced by their single exposure.

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