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Qu Y, Guan R, Bose J, Henderson SW, Wege S, Qiu L, Gilliham M. Soybean CHX-type ion transport protein GmSALT3 confers leaf Na + exclusion via a root derived mechanism, and Cl - exclusion via a shoot derived process. Plant Cell Environ 2021; 44:856-869. [PMID: 33190315 DOI: 10.1111/pce.13947] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 06/11/2023]
Abstract
Soybean (Glycine max) yields are threatened by multiple stresses including soil salinity. GmSALT3 (a cation-proton exchanger protein) confers net shoot exclusion for both Na+ and Cl- and improves salt tolerance of soybean; however, how the ER-localized GmSALT3 achieves this is unknown. Here, GmSALT3's function was investigated in heterologous systems and near isogenic lines that contained the full-length GmSALT3 (NIL-T; salt-tolerant) or a truncated transcript Gmsalt3 (NIL-S; salt-sensitive). GmSALT3 restored growth of K+ -uptake-defective Escherichia coli and contributed towards net influx and accumulation of Na+ , K+ and Cl- in Xenopus laevis oocytes, while Gmsalt3 was non-functional. Time-course analysis of NILs confirmed shoot Cl- exclusion occurs distinctly from Na+ exclusion. Grafting showed that shoot Na+ exclusion occurs via a root xylem-based mechanism; in contrast, NIL-T plants exhibited significantly greater Cl- content in both the stem xylem and phloem sap compared to NIL-S, indicating that shoot Cl- exclusion likely depends upon novel phloem-based Cl- recirculation. NIL-T shoots grafted on NIL-S roots contained low shoot Cl- , which confirmed that Cl- recirculation is dependent on the presence of GmSALT3 in shoots. Overall, these findings provide new insights on GmSALT3's impact on salinity tolerance and reveal a novel mechanism for shoot Cl- exclusion in plants.
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Affiliation(s)
- Yue Qu
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Rongxia Guan
- The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jayakumar Bose
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Sam W Henderson
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Stefanie Wege
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Lijuan Qiu
- The National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
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