EXPRESSION OF THE YEAST HAL2 GENE IN TOMATO INCREASES THE IN-VITRO SALT TOLERANCE OF TRANSGENIC PROGENIES

Agrobacterium-mediated transformation has been used to introduce the y east halotolerant HAL2 as well as the nptII and uidA marker genes into tomato (Lycopersicon esculentum) cv. UC82B. Five to six percent of th e explants produced transgenic plants. HAL2 expressing transformants w ere allowed to self-pollinate and salt tolerance assays were performed in vitro on progenies from two independent transgenic plants with dif ferent levels of expression of the transgene. In vitro salt tolerance was evaluated according to the level of growth of hypocotyl-derived ca lli as well as the rooting capability of isolated shootlets on MS-modi fied medium supplemented with NaCl. Under salt stress, callus formatio n from hypocotyl explants was higher on both transgenic-derived progen ies than in the control. In addition, progenies from the plant with th e highest expression of the transgene (2H20b), also showed a higher le vel of root production on NaCl-supplemented medium. These results sugg ested a positive effect of the yeast HAL2 gene on the level of salt to lerance in progenies derived from transgenic plants. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.