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A rice sitl1 mutant induced by gamma-ray irradiation shows enhanced insensitivity to salinity via reduced accumulation in Na+ and Mg2+
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  • Sung Don Lim,
  • Jong Ho Kim,
  • Jeongeun Lee,
  • Sung-Goo Hwang,
  • Cheol Seong Jang
Sung Don Lim
Kangwon National University
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Jong Ho Kim
Kangwon National University
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Jeongeun Lee
Kangwon National University
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Sung-Goo Hwang
Sang Ji University
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Cheol Seong Jang
Kangwon National University
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Abstract

Salinity stress is one of the most important abiotic stress factors affecting rice (Oryza sativa) production worldwide. Using a forward genetics approach, we isolated a salt insensitive TILLING line 1 (sitl1) rice mutant from a gamma-ray irradiated TILLING population. This sitl1 mutant line showed increased salinity tolerance due to reduced Mg2+ and Na+ uptake in root and shoot tissues and in the xylem sap. Whole genome resequencing and RNA-sequencing analyses identified a single nucleotide T insertion in exon 5 of Os01g47460 (putative metal ion transporter) with the CorA-like ZntB cation transfer domain (OsMGT1). Transient expression of the OsMGT1-sGFP fusion protein in rice protoplasts showed OsMGT1 was localized to the plasma membrane. Expression analysis of various tissues and at different growth stages showed that the OsMGT1 was mainly expressed in roots and leaf tissues as an early response to salinity stress. Complementation and overexpression assays in the yeast (Saccharomyces cerevisiae) CM66 strain and wild type showed that the OsMGT1 protein possessed both Mg2+ and Na+ transport activity. Taken together, the mutation of the OsMGT1 gene in the sitl1 mutant reduced the transport abilities of both Na+ and Mg2+ conferring salinity insensitivity in rice.

Peer review status:UNDER REVIEW

24 Apr 2020Submitted to Plant, Cell & Environment
28 Apr 2020Assigned to Editor
28 Apr 2020Submission Checks Completed
07 May 2020Reviewer(s) Assigned
11 Jun 2020Review(s) Completed, Editorial Evaluation Pending