Solar radiation is a source of energy for photosynthesis and an important signal for regulation of plant growth and development. However, high light intensity, and especially ultraviolet radiation, can cause stress in plants. H2O2 and proline content, lipid peroxidation level, activity of antioxidant enzymes and efficiency of photosynthesis are measurable parameters for assessing the stress effect on plants. The main goal of the research was to evaluate the effect of UV-B radiation on model plant Arabidopsis thaliana. Besides wild-type, the lines with modified expression of BPM genes (oeBPM1 and amiR-bpm) were used. BPM1 protein belongs to the MATH-BTB (BPM) protein family that participate in developmental processes and stress response in plants. Immunodetection of BPM1-GFP protein in oeBPM1 confirmed the highest accumulation of the protein after treatment with UV-B radiation dose of 831 J cm-2 . The comparison of control and treated plants showed that this dose of UV-B radiation induced changes in the content of H2O2 in wild type and oeBPM1, in guaiacol peroxidase and superoxide dismutase activity in wild type, and in the maximum quantum efficiency of PSII in oeBPM1. Moreover, a difference between tested lines was more pronounced than difference between control and treated plants of the same line. The oeBPM1 line showed better stress response than other two lines due to more pronounced activation of antioxidant enzymes, while the amiR-bpm line had higher H2O2 content and lipid peroxidation level compared to wild type and oeBPM1. Because these lines differ in expression of BPM genes, their involvement in the UV-B radiation response is possible.