THE DYNAMICS OF SUPEROXID DISMUTASE ACTIVITY AND ITS GENE EXPRESSION IN WHEAT LEAVES DURING COLD ADAPTATION

Abstract

The effect of low hardening temperature (4 ° С) on the dynamics of the enzyme superoxide dismutase (SOD) activity and the transcript accumulation of its encoding genes – FeSOD and MnSOD – in the leaves of 7‑day-old seedlings of winter wheat ( Triticum aestivum L.) variety Moscowskaya 39 was investigated. It was shown that already in 1 hour from the beginning of the treatment, the hardening temperature of 4 ° С causes a significant increase in cold tolerance of the seedlings, which then continues to increase monotonically, reaching a peak on the 7 th day of the experiment. The process of cold adaptation in wheat seedlings was accompanied by an increase in SOD activity in wheat leaves, observed as soon as 1 hour after the beginning of the treatment. As the cold exposure continued, there was a further increase in SOD activity, which peaked on the 7 th day of the experiment. In addition, it was determined that the increase in total SOD activity was accompanied by the accumulation of FeSOD and MnSOD gene transcripts in the seedlings’ leaves. The level of FeSOD gene mRNA rose significantly earlier (1 hour from the start of exposure to a temperature of 4 ° С) than MnSOD gene mRNA (after 1 day), and FeSOD mRNA level remained higher than MnSOD mRNA level throughout the period of cold exposure. Based on our results, we can conclude that the increase of SOD activity and upregulation of MnSOD and FeSOD genes under low hardening temperature enable effective neutralization of superoxide radicals and represent an important element in the process of cold adaptation in winter wheat plants.