Expressing the yeast HAL1 gene in tomato increases fruit yield and enhances K+/Na+ selectivity under salt stress

The yeast HAL1 gene facilitates K+/Na+ selectivity and salt tolerance of ce lls. Ectopic expression of HAL1 in transgenic tomato (Lycopersicon esculent um Mill.) plants minimized the reduction in fruit production caused by salt stress. Maintenance of fruit production by transgenic plants was correlate d with enhanced growth under salt stress of calli derived from the plants. The HAL1 transgene enhanced water and K+ contents in both leaf calli and le aves in the presence of salt, which indicates that HAL1 functions in plants using a similar mechanism to that in yeast, namely by facilitating K+/Naselectivity under salt stress.