Savanna Journal of Basic and Applied Sciences 1(1):84 - 90
Salt Stress Responses and Protein Expression Changes in Tomato
I. I. Hamma, A. A. Aliero, H. M. Maishanu, and A.Y. Abbas,

Tomato is a model plant for studying the mechanisms of plant salt tolerance. Responses of Tomato (Lycopersicon esculentum Mill) to various concentrations of salt and changes in some protein expression levels were investigated. Seeds of three (3) varieties of tomato namely, Roma vf, Rio Grande and UC 82 B were germinated on a nursery bed and seedlings were transferred to polythene bags supplemented with 0, 20, 40 and 60 mM NaCl. After 24 days, growth parameters, floral number, free Proline content, Glycine betaine content, shoot dry weight were measured using standard methods and procedures. Leaf samples were collected for protein extraction and the alterations in expression levels induced in leaf proteins under salt stress treatments were studied by one-dimensional SDS-PAGE. Increasing concentration of NaCl decreased in all growth parameters (floral number, number of leaves, plant height and dry weight) evaluated. Free Proline and Glycine betaine content increased significantly (P < 0.05) in salt-treated plants compared with the control. The content ranges from 1.56-1.99 mM in Roma vf, 1.32-1.99 mM in UC 82 B, and 1.77-1.99 mM, 1.95-1.99mM in Rio Grande. SDS-PAGE showed up-regulation of at least nine proteins with a molecular weight of 46, 35, 25 and 12 kD in leaves of UC 82 B, 45, 25, 19 and 17 kD in leaves of Roma vf and 38 kD in leaves of Rio Grande. At least three proteins with a molecular weight of 29 kD in leaves of Roma vf and 45 and 53 kD in leaves of Rio Grande were down-regulated. From the results of this study, it was observed that Tomato Roma vf is more tolerant to salt stress followed by UC 82 B and the Rio Grande, and therefore could be selected as the salt-tolerant variety to ameliorate production loss.