The Effect of Ultraviolet-C radiation on Expression Pattern of some enzymes involved in the Programmed Cell Death of Bread Wheat

Wheat is one of the plants that is important in terms of diet and business, and the global demand for it is increasing. One of the harmful and dangerous stresses is ultraviolet light, which affects the growth and production of plants and leads to the production of reactive oxygen species, which are very toxic. The present study was evaluated in order to investigate the effect of C type ultraviolet light on seedlings of three varieties of wheat in order to identify the systems involved in transmitting the defense message of this plant from biochemical and molecular aspects.
 
The experiment was carried out in a factorial manner based on a completely randomized design with three replications at Mohaghegh University of Ardabil. The investigated factors included the first factor of Control and treatment with ultraviolet light (type C with a wavelength of 254 nm) and the second factor of wheat cultivars (Sardari, Morvarid, and Gaspard). Type C ultraviolet light stress was applied at the stage of three-four leaves for 20 minutes and then sampling of the treated leaves at zero, 1, 2, 4, 6, 10, 18, 24 and 48 hours later. The treatment was done.
 
The results showed that the quantitative activity of peroxidases in Sardari and Gaspard cultivars was not significantly different in front of type C ultraviolet light, while in Morvarid cultivar, this enzyme increase had an upward trend from the very first hours. Also, the results of the qualitative examination of peroxidase enzymes against C type ultraviolet light showed the number of 5, 6 and 9 peroxidase isoenzymes in three of Sardari, Morvarid and Gaspard wheat cultivars. Qualitative analysis of catalase enzymes in Sardari and Gaspard cultivars identified 4 isoenzymes and 3 isoenzymes in Morvarid cultivar. On the other hand, in DNA electrophoresis, the effect of type C ultraviolet light on the DNA of three wheat cultivars showed that DNA breakage occurred in Sardari and Gaspard cultivars 48 hours after treatment compared to control samples and in Morvarid cultivar, from the first hours after treatment. Investigation the changes in expression of genes involved in metabolism such as hexokinase and plant defense such as PR1 in three wheat cultivars as a result of treatment with type C ultraviolet light shows that the expression changes of these two genes in Sardari and Gaspard cultivars follow almost the same pattern and 10 hours after From the treatment, they have shown a decrease in expression, but in Morvarid cultivar, the expression of HK and PR1 genes increased from the very first hours.
 
In general, the results show that the increase in the activity of peroxidase and catalase enzymes and changes in the expression of PR1 and HK genes in the path of transmission of ultraviolet light C type in three cultivars Sardari, Morvarid and Gaspard gives. DNA breakage along with other changes in wheat indicate the possibility of programmed cell death in wheat.