The effects of NARK gene and nitrogen on growth and leaf protein profile of wild-type and supernodulation mutant of soybean

Nitrogen is one of the most important elements required by plants. Legume crops are of great significance because they can use nitrogen from the atmosphere through biological nitrogen fixation. In the current study, effects of NARK gene and different nitrogen treatments on growth, physiological parameters and protein profile of soybean leaf of supernodulation mutant and wild-type were investigated. For this, a factorial experiment in a completely randomized design with three replications was conducted under greenhouse conditions. Experiment factors included two levels of ammonium (NH4+) and two levels of nitrate (NO3-) for three types of soybean (sterile, wild-type and supernodulating mutant). Results of variance analysis revealed that the treatment of ammonium plus nitrate in comparison with other treatments had the greatest effect on soybean plants in terms of morphological and biochemical parameters. Two-dimensional electrophoresis also showed that sterile plants under 5mM ammonium sulfate treatment had higher protein variation in leaf compared with the soybean wild-type plants inoculated with rhizobia (non-recipient of mineral nitrogen). This variation in the leaf protein profile of plants could be due to type of nitrogen they receive (mineral nitrogen/biological nitrogen fixation). In addition, the protein variation could be due to alteration in genes expression because of symbiosis in inoculated plants with rhizobia. Traits such as chlorophyll b, total chlorophyll, carotenoids, and reduced sugar content, had the highest amount under the ammonium plus nitrate and 5mM ammonium treatments and the lowest amount in control plants.