Stressed Out: ExploringArabidopsis thalianaMutants Under Drought andSalt Stress

Circadian clocks help plants align internal processes with daily environmental cycles, regulating important functions like photosynthesis, leaf movement and stomatal activity. The circadian clock help maintain ~24-hour rhythms. Soil salinity is a major global stressor as its disrupts germination and growth by inducing osmotic and oxidative stress, making it critical to understand how circadian regulation affects plant stress responses. This study explores the roles of four core clock genes; OPEN STOMATA 1 (OST1), PSEUDO- RESPONSE REGULATOR 5 (PRR5), TIMING OF CAB EXPRESSION 1 (TOC1), and ZETLUPE (ZTL). Screening for traits was done with aim of finding mutant lines with significant deviations from responses in the reference genome, col-0, either in heightened sensitivity or increased tolerance when being exposed for salt or osmotic stress. Wild-type genotype and mutant lines of seedlings were cultured on Murashige and Skoog medium supplemented with NaCl to simulating different stress conditions. Growth parameters, including germination efficiency, hypocotyl elongation, and root elongation, were measured and analyzed statistically. Results revealed that single mutations for dysfunction in TOC1, OST1 and PRR5 displayed distinct responses for stressors, depending on what gene that was disrupted. High-order mutants generally exhibited compounded effects where mutations in several genes induced a greater sensitivity for stressors. The interactions among circadian genes suggest a complex regulatory network governing plant stress response.