The full length cDNA coding for a novel vacuolar Na+/H+ antiporter (GmNHX1) was cloned from soybean and determined to consist of 2591 bp with a 5′-untranslated region of 464 bp, an open reading frame (ORF) of 1641 bp...The full length cDNA coding for a novel vacuolar Na+/H+ antiporter (GmNHX1) was cloned from soybean and determined to consist of 2591 bp with a 5′-untranslated region of 464 bp, an open reading frame (ORF) of 1641 bp, and a 3′-untrans- lated region of 486 bp. The deduced protein se- quence contains 546 aa with the typical characters of the vacuolar Na+/H+ antiporters, and shares high similarity with that of AtNHX1, OsNHX1 and AgNHX1. The soybean genome showed a single copy of the GmNHX1 gene. Northern blot analysis demonstrated that the expression of the GmNHX1 was tissue-spe- cific, increased by ABA treatment, NaCl, KCl, LiCl and dehydration stress, and lower in leaves but higher in roots and hypocotyls of salt-tolerant than salt-sensitive cultivars. The GmNHX1 was overex- pressed under the control of a tandem cauliflower mosaic virus (CaMV) 35S promoter in the model le- guminous plant Lotus corniculatus L. and conferred salt-tolerance of the transgenic plants. Measure- ments of Na+ and K+ contents in both roots and shoots demonstrated that the plantlets of GmNHX1- overexpressing lines had lower Na+ and K+ content, and higher K+/Na+ ratio than the controlled lines that were transformed with the empty vector, which indi- cates that the salt-tolerance conferred by GmNHX1 is closely related with decreased accumulation of Na+ in the transgenic plants.展开更多
文摘The full length cDNA coding for a novel vacuolar Na+/H+ antiporter (GmNHX1) was cloned from soybean and determined to consist of 2591 bp with a 5′-untranslated region of 464 bp, an open reading frame (ORF) of 1641 bp, and a 3′-untrans- lated region of 486 bp. The deduced protein se- quence contains 546 aa with the typical characters of the vacuolar Na+/H+ antiporters, and shares high similarity with that of AtNHX1, OsNHX1 and AgNHX1. The soybean genome showed a single copy of the GmNHX1 gene. Northern blot analysis demonstrated that the expression of the GmNHX1 was tissue-spe- cific, increased by ABA treatment, NaCl, KCl, LiCl and dehydration stress, and lower in leaves but higher in roots and hypocotyls of salt-tolerant than salt-sensitive cultivars. The GmNHX1 was overex- pressed under the control of a tandem cauliflower mosaic virus (CaMV) 35S promoter in the model le- guminous plant Lotus corniculatus L. and conferred salt-tolerance of the transgenic plants. Measure- ments of Na+ and K+ contents in both roots and shoots demonstrated that the plantlets of GmNHX1- overexpressing lines had lower Na+ and K+ content, and higher K+/Na+ ratio than the controlled lines that were transformed with the empty vector, which indi- cates that the salt-tolerance conferred by GmNHX1 is closely related with decreased accumulation of Na+ in the transgenic plants.
