The Arabidopsis Mutant of the Small Intrinsically Disordered Protein DSS1(V) Exhibits Increased Sensitivity to Drought Stress

Drought has emerged as one of the most severe and widespread environmental stresses affecting plants. Crops exposed to varying levels of drought, ranging from moderate to severe, often experience notable declines in yield or reduced harvest quality. Investigating the molecular mechanisms and cellular factors involved in plant defense against drought is crucial-not only for advancing our understanding of these processes but also for ensuring sustainable food production and supporting humanity's survival. Our previous work identified the small intrinsically disordered protein DSS1 (deleted in split-hand/split-foot) as a key factor in the stress defense mechanisms of <i>Arabidopsis thaliana</i>. The absence of DSS1(V) led to increased sensitivity of plants to oxidative stress induced by hydrogen peroxide or methyl viologen. As drought can induce oxidative stress in plant cells, we investigated if DSS1(V) protein can mitigate stress caused by mild to moderate drought. Alongside the wild-type (WT) strain, the analysis included knockout plants lacking the DSS1(V) gene and plants overexpressing this gene. Various stress-related parameters, including lipid peroxidation, total phenol content, chlorophyll levels, and protein oxidation, were measured. Results indicated that the DSS1(V) knockout line displayed significantly higher sensitivity to drought compared to WT plants. However, elevated levels of DSS1(V) transcripts in the overexpressing lines did not confer a protective effect, as these lines did not exhibit reduced drought sensitivity. These findings provide compelling evidence highlighting the critical involvement of the DSS1(V) protein in the mechanisms underlying plant responses to environmental stress, particularly water deficiency. This protein appears to enable plants to cope with the challenges posed by drought conditions, emphasizing its importance in maintaining cellular homeostasis and mitigating the adverse effects of water scarcity.