Studies on the overexpression of the soybean GmNHX1 in Lotus corniculatus: The reduced Na^+ level is the basis of the increased salt tolerance  

作　　者：SUN Yanxiang WANG Dan BAI Yanling WANG Ningning WANG Yong 

机构地区：[1]College of Life Sciences, Nankai University, Tianjin 300071, China [2]Tianjin Research Center of Agricultural Biotechnology, Tianjin 300183, China [3]Department of Biology, Teachers College of Langfang, Langfang 065000, China

出　　处：《Chinese Science Bulletin》2006年第11期1306-1315,共10页

摘　　要：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.The full length cDNA coding for a novel vacuolar Na^＋/H^＋ antiporter （GmNHXl） 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＇-untranslated region of 486 bp. The deduced protein sequence contains 546 aa with the typical characters of the vacuolar Na^＋/H^＋ antiporters, and shares high similarity with that of AtNHXl, OsNHXl and AgNHXl. The soybean genome showed a single copy of the GmNHX1 gene. Northern blot analysis demonstrated that the expression of the GmNHX1 was tissue-specific, 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 GmNHXl was overexpressed under the control of a tandem cauliflower mosaic virus （CaMV） 35S promoter in the model leguminous plant Lotus corniculatus L. and conferred salt-tolerance of the transgenic plants. Measurements 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 indicates that the salt-tolerance conferred by GmNHX1 is closely related with decreased accumulation of Na^＋ in the transgenic plants.

关 键 词：大豆 GmNHX1 莲 耐盐性 盐胁迫 

分 类 号：Q945[生物学—植物学]