Expression of a Novel Antiporter Gene from Brassica napus Resulted in Enhanced Salt Tolerance in Transgenic Tobacco Plants

Abstract

Tobacco leaf discs were transformed with a plasmid pBIBnNHX1, containing the selectable marker neomycin phosphotransferase gene (nptII) and Na+/H+ vacuolar antiporter gene from Brassica napus (BnNHX1), via Agrobacterium tumefaciens-mediated transformation. Thirty-two independent transgenic plants were regenerated. Polymerase chain reaction (PCR) and Southern blot analyses confirmed that the BnNHX1 gene had integrated into plant genome and Northern blot analysis revealed the transgene expression at various levels in transgenic plants. Transgenic plants expressing BnNHX1 had enhanced salt tolerance and could grow and produce seeds normally in the presence of 200 mM NaCl. Analysis for the T1 progenies derived from seven independent transgenic primary transformants expressing BnNHX1 showed that the transgenes in most tested independent T1 lines were inherited at Mendelian 3:1 segregation ratios. Transgenic T1 progenies could express BnNHX1 and had salt tolerance at levels comparable to their T0 parental lines. This study implicates that the BnNHX1 gene represents a promising candidate in the development of crops for enhanced salt tolerance by genetic engineering.