title: Wheat grain yield on saline soils is improved by an ancestral Na⁺ transporter gene.
abstract: The ability of wheat to maintain a low sodium concentration ([Na(+)]) in leaves correlates with improved growth under saline conditions. This trait, termed Na(+) exclusion, contributes to the greater salt tolerance of bread wheat relative to durum wheat. To improve the salt tolerance of durum wheat, we explored natural diversity in shoot Na(+) exclusion within ancestral wheat germplasm. Previously, we showed that crossing of Nax2, a gene locus in the wheat relative Triticum monococcum into a commercial durum wheat (Triticum turgidum ssp. durum var. Tamaroi) reduced its leaf [Na(+)] (ref. 5). Here we show that a gene in the Nax2 locus, TmHKT1;5-A, encodes a Na(+)-selective transporter located on the plasma membrane of root cells surrounding xylem vessels, which is therefore ideally localized to withdraw Na(+) from the xylem and reduce transport of Na(+) to leaves. Field trials on saline soils demonstrate that the presence of TmHKT1;5-A significantly reduces leaf [Na(+)] and increases durum wheat grain yield by 25% compared to near-isogenic lines without the Nax2 locus.
authors.affiliation: CSIRO Plant Industry, Canberra, Australian Capital Territory, Australia.
authors.forename: Rana
authors.initials: R
authors.lastname: Munns
authors.forename: Richard A
authors.initials: RA
authors.lastname: James
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.forename: Asmini
authors.initials: A
authors.lastname: Athman
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Conn
authors.forename: Charlotte
authors.initials: C
authors.lastname: Jordans
authors.forename: Caitlin S
authors.initials: CS
authors.lastname: Byrt
authors.forename: Ray A
authors.initials: RA
authors.lastname: Hare
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Tyerman
authors.forename: Mark
authors.initials: M
authors.lastname: Tester
authors.forename: Darren
authors.initials: D
authors.lastname: Plett
authors.forename: Matthew
authors.initials: M
authors.lastname: Gilliham
mesh_terms: D000818:Animals; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D003433:Crosses, Genetic; D002523:Edible Grain / Q000235:genetics / Q000254:growth & development*; D008969:Molecular Sequence Data; D009865:Oocytes; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D055051:Salt-Tolerant Plants / Q000235:genetics / Q000254:growth & development; D012964:Sodium / Q000378:metabolism*; D012987:Soil; D027981:Symporters / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D014908:Triticum / Q000235:genetics* / Q000254:growth & development; D014982:Xenopus laevis; D052584:Xylem / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; C088864:HKT1 protein, plant; D010940:Plant Proteins; D012987:Soil; D027981:Symporters; D012964:Sodium