putative plasma membrane cation/proton antiporter from soybean confers salt tolerance in Arabidopsis

• Published in: Plant molecular biology 2005-11, Vol.59 (5), p.809-820
• Main Authors: Luo, G.Z, Wang, H.W, Huang, J, Tian, A.G, Wang, Y.J, Zhang, J.S, Chen, S.Y
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; antiporters; Antiporters - chemistry; Antiporters - genetics; Antiporters - metabolism; Arabidopsis; Arabidopsis - cytology; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; Calcium-Binding Proteins - chemistry; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Cation Transport Proteins - chemistry; Cation Transport Proteins - genetics; Cation Transport Proteins - metabolism; cation/proton antiporter; Cell Membrane - metabolism; Flowers & plants; gene expression; Gene Expression Regulation, Plant; gene transfer; genes; Glycine max; Glycine max - genetics; GmCAX1 gene; Homeostasis; ion transport; lithium; Lithium - metabolism; Lithium - pharmacology; messenger RNA; Molecular Sequence Data; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; plasma membrane; potassium; Salt tolerance; Sequence Alignment; Sequence Homology, Amino Acid; sodium; Sodium Chloride - metabolism; Sodium Chloride - pharmacology; Soybeans; transgenic plants
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-005-1386-0

Cation transport is thought to be an important process for ion homeostasis in plant cells. Here, we report that a soybean putative cation/proton antiporter GmCAX1 may be a mediator of this process. GmCAX1 is expressed in all tissues of the soybean plants but at a lower level in roots. Its expression was induced by PEG, ABA, Ca(2+), Na(+) and Li(+) treatments. The GmCAX1-GFP fusion protein was mainly localized in plasma membrane of the transgenic Arabidopsis plant cells and onion epidermal cells. Transgenic Arabidopsis plants overexpressing GmCAX1 accumulated less Na(+), K(+), and Li(+), and were more tolerant to elevated Li(+) and Na(+) levels during germination when compared with the controls. These results suggest that GmCAX1 may function as an antiporter for Na(+), K(+) and Li(+). Modulation of this antiporter may be beneficial for regulation of ion homeostasis and thus plant salt tolerance.