title: A constitutively active form of a durum wheat Na⁺/H⁺ antiporter SOS1 confers high salt tolerance to transgenic Arabidopsis.
abstract: 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.
authors.affiliation: Plant Protection and Improvement Laboratory, Centre of Biotechnology of Sfax (CBS), Route Sidi Mansour Km 6, B.P '1177', 3018, Sfax, Tunisia.
authors.forename: Kaouthar
authors.initials: K
authors.lastname: Feki
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Quintero
authors.forename: Habib
authors.initials: H
authors.lastname: Khoudi
authors.forename: Eduardo O
authors.initials: EO
authors.lastname: Leidi
authors.forename: Khaled
authors.initials: K
authors.lastname: Masmoudi
authors.forename: Jose M
authors.initials: JM
authors.lastname: Pardo
authors.forename: Faiçal
authors.initials: F
authors.lastname: Brini
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D001692:Biological Transport; D018533:Biomass; D002462:Cell Membrane / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D006706:Homeostasis; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D055049:Salt Tolerance; D036226:Seedlings / Q000235:genetics / Q000502:physiology; D012965:Sodium Chloride / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics* / Q000378:metabolism; D019076:Transgenes; D014908:Triticum / Q000235:genetics; D014867:Water / Q000032:analysis / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D017923:Sodium-Hydrogen Exchangers; D014867:Water; D012965:Sodium Chloride