Molecular characterization of GmNHX2,a Na^+/H^+ antiporter gene homolog from soybean,and its heterologous expression to improve salt tolerance in Arabidopsis  

作　　者：ZHOU GuoAn GUAN RongXia LI YingHui CHANG RuZhen QIU LiJuan 

机构地区：[1]National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI)/Key Lab of Germplasm & Biotechnology (MOA), Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China

出　　处：《Chinese Science Bulletin》2009年第19期3536-3545,共10页

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 30490251);National High Technology Research and Development Program of China (Grant Nos. 2006AA10A110, 2006AA100104);Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period (Grant No. 2006BAD13B05)

摘　　要：Na+/H+ antiporters have been well documented to enhance plant salt tolerance by regulating cellular ion homeostasis. Here, a putative Na+/H+ antiporter gene homolog GmNHX2 from soybean was cloned and predicted to encode a protein of 534 amino acids with 10 putative transmembrane domains. GmNHX2 was expressed in all soybean plant tissues but enriched in roots and its expression was induced by NaCl and polyethylene glycol (PEG) treatments. GmNHX2 exhibits greater sequence similarity with LeNHX2 and AtNHX6 than that of AtNHX1 and AtSOS1. Although phylogenetic analysis clustered GmNHX2 with organellar (tonoplast and vesicles) antiporters, the GmNHX2-EGFP (enhanced green fluorescent protein) fusion protein was possibly localized in the plasma membrane or organelle membrane of transgenic plant cells. Furthermore, transgenic Arabidopsis plants expressing GmNHX2 were more tolerant to high NaCl concentrations during germination and seedling stages when compared with wild-type plants. These results suggest that GmNHX2 is a membrane Na+/H+ antiporter and may function to regulate ion homeostasis under salt stress.Na＋/H＋ antiporters have been well documented to enhance plant salt tolerance by regulating cellular ion homeostasis. Here, a putative Na＋/H＋ antiporter gene homolog GmNHX2 from soybean was cloned and predicted to encode a protein of 534 amino acids with 10 putative transmembrane domains. GmNHX2 was expressed in all soybean plant tissues but enriched in roots and its expression was induced by NaCI and polyethylene glycol （PEG） treatments. GmNHX2 exhibits greater sequence similarity with LeNHX2 and AtNHX6 than that of AtNHX1 and AtSOS1. Although phylogenetic analysis clustered GmNHX2 with organellar （tonoplast and vesicles） antiporters, the GmNHX2-EGFP （enhanced green fluorescent protein） fusion protein was possibly localized in the plasma membrane or organelle membrane of transgenic plant cells, Furthermore, transgenic Arabidopsis plants expressing GmNHX2 were more tolerant to high NaCl concentrations during germination and seedling stages when compared with wild-type plants. These results suggest that GmNHX2 is a membrane Na＋/H＋ antiporter and may function to regulate ion homeostasis under salt stress.

关 键 词：植物耐盐基因工程 盐胁迫 离子分布 植物组织 GmNHX2 

分 类 号：Q94[生物学—植物学]