The analyses of expression in rice plant tissues and knockout mutants of a rice vacuolar Na⁺/H⁺ antiporter gene (OsNHX1)

Abstract

We have reported that a rice vacuolar Na⁺/H⁺ antiporter, OsNHX1, play important roles in the tolerance of rice to salt and iron-deficiency stresses. We examined the expression pattern of OsNHX1 using transgenic rice carrying β-glucuronidase (GUS) gene under the control of the OsNHX1 promoter region. GUS activity was detected mainly in central cylinder and the bottom of lateral roots in rice roots, and in guard cells and vascular bundle in leaves. We isolated two rice osnhx1 mutants from Tos17 insertional mutants. No significant differences were observed in the growth between wild-type and mutant cells and plants under salt and osmotic stresses. In addition, we found no significant differences in the main elements between wild-type and mutant cells, and in Na⁺ and K⁺ contents between wild-type and mutant plants. We will show the expression of other NHX-type genes in osnhx1 mutants and discuss the physiological roles of OsNHX1 in rice.