Comparison of the Protein Profile of Rejaw Wheat based on Changes in the pH Range

Today, wheat is grown on more land area than any other commercial crop and continues to be the most important food grain source for humans. Rejaw cultivar is adaptable to the conditions of rainfed cultivation and supplementary irrigation in the cold regions of Iran. Of course, it can play an essential role in increasing and sustaining the yield of rainfed wheat. Regarding the quality of the resulting flour, Rejaw has a high quality, increasing the bread quality and reducing bread waste. Two-dimensional electrophoresis is a combination of isoelectric focusing (IEF) in the first dimension and SDS-PAGE in the second dimension, which allows the separation of proteins based on electrical charge and molecular weight.

In this study, Rejaw wheat variety was used to investigate the changes of protein spots in two different ranges of linear pH 4 to 7 and nonlinear pH 3 to 10. For this purpose, bread wheat seed sample of Rejaw cultivar obtained from the Dryland Agricultural Research Institute (Sararoud branch), Kermanshah, Iran, was grown in a greenhouse under normal conditions in a pot; during the experiment, the lighting period was 14 hours, and natural lighting and fluorescent lamps were used to adjust this light. The daily temperature was about 20 degrees Celsius and the night temperature was about 10 to 12 degrees Celsius. Finally, leaf samples were used in protein extraction to perform two-dimensional electrophoresis, and their total protein was extracted. The experiment was carried out in the greenhouse of Payam-Noor University and the protein department laboratory of the Medical Biology Research Center of Kermanshah University of Medical Sciences.

The results showed the changes of the expressed proteins in two different pH 4 to 7 linear and 3 to 10 non-linear. Although the resolution of the image and the separation of the protein spots at pH 3 to 10 were nonlinear due to the wider pH range, the movement of the proteins in two-dimensional electrophoresis showed that these molecules, in addition to the pI difference, have a solvable behavior. Attention in the conditions of SDS-PAGE and two-dimensional electrophoresis, which is not seen in the usual SDS-PAGE method. In other words, in two-dimensional electrophoresis, proteins are separated based on electric charge and molecular weight but in one-dimensional electrophoresis, they are separated based on molecular weight. For this reason, a set of proteins may have the same molecular weight.

However, this degree of protein diversity and relatively heterogeneous electrophoretic behavior of the proteins obtained from the leaves of Rejaw cultivar, which was apparently only shown in this study with two-dimensional electrophoresis, is remarkable and requires more studies in other related species. The results obtained from the two-dimensional electrophoresis study in this study can open the way for proteomic studies in the future.