engleski

HEAT STRESS RESPONSE IN ARABIDOPSIS WITH MODIFIED DMS3 EXPRESSION

The protein DEFECTIVE IN MERISTEM SILENCING 3 (DMS3) is one of the key components of RNA-directed DNA methylation (RdDM). By mediating DNA methylation, RdDM has a role in controlling genome integrity and gene expression, particularly during plant acclimation to fluctuating environmental conditions. The aim of this study was to question the impact of elevated temperature on selected physiological and biochemical parameters in Arabidopsis thaliana with modified DMS3 expression. Seedlings with overexpressed DMS3 gene (oeDMS3 line) or non-functional DMS3 protein (dms3-1 line) together with the wild type (wt), were cultured at temperature of 24 °C and subsequently exposed to 37 °C for six hours. Plant material was collected at two time points - immediately after the treatment and after a 24-hour recovery period at 24 °C. In dms3-1 line, exposure to 37 °C resulted in a decrease of photosynthetic performance at both time points. Increased proline and MDA content were observed only in dms3-1 after recovery. In oeDMS3 line, guaiacol peroxidase (G-POD), ascorbate peroxidase (APX), and catalase (CAT) activity increased immediately after the treatment, whereas superoxide dismutase (SOD) increased after recovery. In dms3-1 line, only CAT activity increased immediately after the treatment, whereas G POD decreased at both time points. It can be concluded that dms3-1 was more heat-sensitive than oeDMS3 and wt, suggesting that the DMS3 protein is required for heat tolerance in Arabidopsis.

RdDM, photosynthesis, proline, antioxidant enzymes, lipid peroxidation

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