Abstract
Vacuolar Na+/H+ antiporter transports Na+ from the cytoplasm to vacuoles using a pH gradient generated by proton pumps. We have already isolated a NHX-type vacuolar Na+/H+ antiporter gene (OsNHX1) from rice. In addition, we have identified three members (OsNHX2-4) of rice NHX-type antiporter gene family by analysis of the recently completed rice genome database (1). The deduced amino acid sequence of OsNHX1 has high similarity with OsNHX2 (75%) and OsNHX3 (71%), and is similar to OsNHX4 with 33% identity. Overexpression of the OsNHX2 and OsNHX3 genes suppressed NaCl, KCl and hygromycin sensitivity of the yeast nhx1 mutant. The expression of the OsNHX1-3 showed different patterns in rice treated with salt or osmotic stress. In this report, we will also show the result of OsNHX4.
(1) Goff, S. et al. (2002) Science 296, 92-100.
