Hide/Show Apps

Cu/Zn superoxide dismutase activity and respective gene expression during cold acclimation and freezing stress in barley cultivars

Kayihan, C.
Afsar, N.
Öktem, Hüseyin Avni
The transcript levels and activities of the superoxide dismutase isoenzyme (Cu/ZnSOD) were assessed in winter (Tarm-92) and spring (Zafer-160) barley cultivars during cold acclimation, freezing stress and after rewarming. Leaf Cu/ZnSOD activity and Cu/ZnSOD expression level were not significantly changed during cold acclimation. The Cu/ZnSOD expression increased evidently at mild freezing stress (-3 A degrees C; F1), while Cu/ZnSOD1 activity did not show any response and Cu/ZnSOD2 activity decreased continuously during F1 and F2 (-7 A degrees C) in Tarm-92. On the other hand, root Cu/ZnSOD2 activity was in accordance with Cu/ZnSOD expression in Zafer-160 after F2 treatment. Rewarming periods did not cause any significant changes in the Cu/ZnSOD activity and expression of Cu/ZnSOD in both cultivars when compared to freezing stresses. These results showed that freezing stress can regulate differently Cu/ZnSOD transcription and enzyme activity.