The effects of chronic radiation of gamma ray on protein expression and oxidative stress in Brachypodium distachyon.

PURPOSE

To compare the effects of gamma-irradiation on biochemical responses and growth, six-week-old Brachypodium plants were chronically exposed to gamma-irradiation for 30 days at various dosages.

MATERIALS AND METHODS

Growth surveys of Brachypodium plants in response to different dosages of gamma-irradiation were conducted to compare physiological changes between irradiated and non-irradiated plants. Photosynthetic pigments, soluble sugar content, activities of antioxidant enzymes, and malonaldehyde (MDA) induced by reactive oxygen species (ROS) production were also measured.

RESULTS

Gamma-irradiation had a negative influence on the average plant height, leaf length, leaf width, and fresh weight. Photosynthetic pigment levels decreased with increasing dosages of gamma-irradiation, while soluble sugar content slightly increased. Gamma-irradiation responsive proteins were detected and identified by two-dimensional gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF). The proteins had a role in photosynthetic carbon fixation, anabolic pathway glycolysis, mitochondrial ATP production, and oxidative stress response regulation. MDA levels and activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD) increased with the increase in gamma-irradiation dosage level.

CONCLUSIONS

This study provides some basic information regarding responses to gamma-irradiation, and provides valuable physiological and biological data on the effects of different gamma-irradiation dosages on Triticeae species.