Abstract
BACKGROUND: Frequent drought and high soil salinity are significant stressors that hinder crop yields worldwide. Understanding gene regulation and underlying stress responses in plants is key to combating abiotic stress. Recent reports have implicated the domain-of-unknown-function (DUF) proteins in plant stress responses. In Arabidopsis, AtDUF569 regulates plant growth and development under oxidative as well as nitro-oxidative stress and modulates plant basal defense. RESULTS: Here, we describe how AtDUF569 bolsters plant responses to salt stress. The atduf569 mutant plants demonstrated a salt-resistant phenotype. The expression of salt overly sensitive (SOS) pathway genes, nitrate reductase, abscisic acid (ABA)-dependent stress-induced genes, and other stress-related genes were altered in atduf569 plants in comparison to wild type. We also measured antioxidant activity, chlorophyll, polyphenol, flavonoid, total carotenoid, protein, malondialdehyde (MDA), ABA, and amino acid content; atduf569 plants had significantly lower levels of superoxide dismutase and polyphenol oxidase, total chlorophyll, polyphenol, flavonoid, carotenoid, protein, and ABA, though a significant increase in MDA content was observed. CONCLUSION: These results indicate that AtDUF569 positively regulates plant responses to salt stress by modulating the expression of SOS pathway genes, potentially through transcriptional or indirect regulatory mechanisms, antioxidant defense and streamlining, photosynthesis, ABA, and secondary metabolites production.