Proteome Analysis of Tobacco (Nicotiana tabacum L.) Leaves under Salt Stress using Two-Dimensional Electrophoresis

In order to understand the response of tobacco (Nicotiana tabacum L.) to salt stress, the comparative analysis of leaf proteome of Basma S. 31 genotype were performed. Plants were treated with or without 200 mM NaCl for 12 days. The proteins were extracted from leaves, and then separated by two-dimensional electrophoresis. The fresh weight and length of shoot of studied genotype showed greater decrease with increasing salinity. The number of 19 protein spots (out of 468 protein spots) was differentially expressed in leaves under NaCl treatment. Although the levels of some proteins were reduced by salt-treatments, an increase of accumulations in some proteins was observed under salt stress. The number of protein spots with increased expression, were higher than the number of protein spots with decreased expression (10 and 9 protein spots, respectively). Results revealed that, spots of 16 and 7 were highly and lowly up-regulated with 6.1-fold and 1.48- fold, respectively. Also, the spot of 18 with 4.4- fold was highly down-regulated among all spots. Salinity is a complex phenomenon that causes not just osmotic and toxic ion effects, but also nutritional and metabolism imbalance. According to the results, it seems that salinity can change the expression levels of some special proteins in leaves of tobacco that may in turn play a role in the tolerance to saline conditions. So, it is believed that increased expression of proteins with low molecular weight that regulate cellular activity, can be effective in tobacco salt tolerance.