Expression of the yeast HAL2 gene in tomato increases the in vitro salt tolerance of transgenic progenies

Abstract

Agrobacterium-mediated transformation has been used to introduce the yeast halotolerant HAL2 as well as the nptII and uidA marker genes into tomato ( Lycopersicon esculentum) cv. UC82B. Five to six percent of the explants produced transgenic plants. HAL2 expressing transformants were allowed to self-pollinate and salt tolerance assays were performed in vitro on progenies from two independent transgenic plants with different levels of expression of the transgene. In vitro salt tolerance was evaluated according to the level of growth of hypocotyl-derived calli as well as the rooting capability of isolated shootlets on MS-modified medium supplemented with NaCl. Under salt stress, callus formation from hypocotyl explants was higher on both transgenic-derived progenies than in the control. In addition, progenies from the plant with the highest expression of the transgene (2H20b), also showed a higher level of root production on NaCl-supplemented medium. These results suggested a positive effect of the yeast HAL2 gene on the level of salt tolerance in progenies derived from transgenic plants.