Enhancing salt tolerance in eggplant by introduction of foreign halotolerance gene, HAL1 isolated from yeast

Agrobacterium-mediated gene transfer method for production of transgenic eggplants (Solanum melongena L. var. PKM1) has been optimized. Polymerase chain reaction of transgenic plants confirmed the presence of the expected HAL1 fragment. Different tests were carried out to evaluate the level of salt tolerance for the transgenic and control plants with culture media in vitro (0, 50, 100, 150, or 200 mM NaCl) and with soil in greenhouse (0, 25, 50, 75, or 100 mM NaCl). Differences in callus growth between transgenic and control lines were observed. At 150 mM NaCl, the weight of calli from the transgenic population did not differ significantly from that in non salt condition, while the growth of wild-type control calli was strongly inhibited. A preliminary evaluation in vivo under controlled greenhouse conditions showed that at moderate salt concentrations (25 mM NaCl), a similar response to salinity in the original line and in the transgenic progeny was found. However, at higher salt concentration (50 mM NaCl), total dry weight (relative growth) was not significantly decreased by salinity in the transgenic population, while a growth reduction was observed in the wild-type control. Our results indicated that a higher level of salt tolerance was found in the transgenic lines than in the wild-type control. Thus, in this present study we have demonstrated the possibility of increasing salt tolerance in eggplant by introducing the foreign gene, HAL1 derived from yeast.