constitutively active form of a durum wheat Na⁺/H ⁺ antiporter SOS1 confers high salt tolerance to transgenic Arabidopsis

• Published in: Plant cell reports 2014-02, Vol.33 (2), p.277-288
• Main Authors: Feki, Kaouthar, Quintero, Francisco J, Khoudi, Habib, Leidi, Eduardo O, Masmoudi, Khaled, Pardo, Jose M, Brini, Faiçal
• Format: Article
• Language: English
• Subjects: Alleles; Arabidopsis; Arabidopsis - genetics; Arabidopsis - physiology; Biological Transport; Biomass; Biomedical and Life Sciences; Biotechnology; Cell Biology; Cell Membrane - metabolism; crops; durum wheat; Gene Expression Regulation, Plant; Germination; Homeostasis; ions; Life Sciences; lithium; mutants; Original Paper; Phenotype; Plant Biochemistry; Plant Leaves - genetics; Plant Leaves - physiology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots - genetics; Plant Roots - physiology; Plant Sciences; Plants, Genetically Modified; plasma membrane; potassium; protons; root growth; roots; salt stress; Salt-Tolerance; salts; seedling growth; Seedlings - genetics; Seedlings - physiology; seeds; shoots; sodium; Sodium Chloride - metabolism; Sodium-Hydrogen Exchangers - genetics; Sodium-Hydrogen Exchangers - metabolism; stress tolerance; Transgenes; transgenic plants; transport proteins; Triticum - genetics; Water - analysis; Water - metabolism; water holding capacity; yeasts
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-013-1528-9

KEY MESSAGE : Expression of a truncated form of wheat TdSOS1 in Arabidopsis exhibited an improved salt tolerance. This finding provides new hints about this protein that can be considered as a salt tolerance determinant. The SOS signaling pathway has emerged as a key mechanism in preserving the homeostasis of Na⁺ and K⁺ under saline conditions. We have recently identified and functionally characterized, by complementation studies in yeast, the gene encoding the durum wheat plasma membrane Na⁺/H⁺ antiporter (TdSOS1). To extend these functional studies to the whole plant level, we complemented Arabidopsis sos1-1 mutant with wild-type TdSOS1 or with the hyperactive form TdSOS1∆972 and compared them to the Arabidopsis AtSOS1 protein. The Arabidopsis sos1-1 mutant is hypersensitive to both Na⁺ and Li⁺ ions. Compared with sos1-1 mutant transformed with the empty binary vector, seeds from TdSOS1 or TdSOS1∆972 transgenic plants had better germination under salt stress and more robust seedling growth in agar plates as well as in nutritive solution containing Na⁺ or Li⁺ salts. The root elongation of TdSOS1∆972 transgenic lines was higher than that of Arabidopsis sos1-1 mutant transformed with TdSOS1 or with the endogenous AtSOS1 gene. Under salt stress, TdSOS1∆972 transgenic lines showed greater water retention capacity and retained low Na⁺ and high K⁺ in their shoots and roots. Our data showed that the hyperactive form TdSOS1∆972 conferred a significant ionic stress tolerance to Arabidopsis plants and suggest that selection of hyperactive alleles of the SOS1 transport protein may pave the way for obtaining salt-tolerant crops.