Ming Zhang, Yibo Cao, Zhiping Wang, Zhi-qiang Wang, Junpeng Shi, Xiaoyan Liang, Weibin Song, Qijun Chen, Jinsheng Lai and Caifu Jiang.A retrotransposon in an HKT1 family sodium transporter causes variation of leaf Na+ exclusion and salt tolerance in maize
发布日期:2019-11-11 浏览次数:  信息来源:生物学院

A retrotransposon in an HKT1 family sodium transporter causes variation of leaf Na+ exclusion and salt tolerance in maizeA retrotransposon in an HKT1 family sodium transporter causes variation of leaf Na+ exclusion and salt tolerance in maize

Ming Zhang, Yibo Cao, Zhiping Wang, Zhi-qiang Wang, Junpeng Shi, Xiaoyan Liang, Weibin Song, Qijun Chen, Jinsheng Lai and Caifu Jiang


New Phytologist

DOI: 10.1111/nph.14882


Summary 

Soil salinity is one of several major abiotic stresses that constrain maize productivity worldwide. An improved understanding of salt-tolerance mechanisms will thus enhance the breeding of salt-tolerant maize and boost productivity. Previous studies have indicated that the maintenance of leaf Na+ concentration is essential for maize salt tolerance, and the difference in leaf Na+ exclusion has previously been associated with variation in salt tolerance between maize varieties. 

Here, we report the identification and functional characterization of a maize salt-tolerance quantitative trait locus (QTL), Zea mays Na+ Content1 (ZmNC1), which encodes an HKT-type transporter (designated as ZmHKT1). 

We show that a natural ZmHKT1 loss-of-function allele containing a retrotransposon insertion confers increased accumulation of Na+ in leaves, and salt hypersensitivity. We next show that ZmHKT1 encodes a plasma membrane-localized Na+-selective transporter, and is preferentially expressed in root stele (including the parenchyma cells surrounding the xylem vessels). We also show that loss of ZmHKT1 function increases xylem sap Na+ concentration and causes increased root-to-shoot Na+ delivery, indicating that ZmHKT1 promotes leaf Na+ exclusion and salt tolerance by withdrawing Na+ from the xylem sap. 

We conclude that ZmHKT1 is a major salt-tolerance QTL and identifies an important new gene target in breeding for improved maize salt tolerance.

 



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