Wheat grain yield on saline soils is improved by an ancestral transporter gene

• Published in: Nature biotechnology 2012-04, Vol.30 (4), p.360
• Main Authors: Munns, Rana, James, Richard A, Xu, Bo, Athman, Asmini, Conn, Simon J, Jordans, Charlotte, Byrt, Caitlin S, Hare, Ray A, Tyerman, Stephen D, Tester, Mark, Plett, Darren, Gilliham, Matthew
• Format: Article
• Language: English
• Subjects: Genetic aspects; Physiological aspects; Sodium channels; Soils, Salts in; Wheat
• ISSN: 1087-0156; 1546-1696
• DOI: 10.1038/nbt.2120

The ability of wheat to maintain a low sodium concentration ([Na+]) in leaves correlates with improved growth under saline conditions (1), (2). This trait, termed Na+ exclusion, contributes to the greater salt tolerance of bread wheat relative to durum wheat (3), (4). 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.