Overexpression of the manganese/cadmium transporter OsNRAMP5 reduces cadmium accumulation in rice grain

Jia Dong Chang, Sheng Huang, Noriyuki Konishi, Peng Wang, Jie Chen, Xin Yuan Huang, Jian Feng Ma, Fang Jie Zhao

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Rice is a major dietary source of the toxic metal cadmium (Cd), and reducing its accumulation in the grain is therefore important for food safety. We selected two cultivars with contrasting Cd accumulation and generated transgenic lines overexpressing OsNRAMP5, which encodes a major influx transporter for manganese (Mn) and Cd. We used two different promoters to control the expression, namely OsActin1 and maize Ubiquitin. Overexpression of OsNRAMP5 increased Cd and Mn uptake into the roots, but markedly decreased Cd accumulation in the shoots, whilst having a relatively small effect on Mn accumulation in the shoots. The overexpressed OsNRAMP5 protein was localized to the plasma membrane of all cell types in the root tips and lateral root primordia without polarity. Synchrotron X-ray fluorescence mapping showed that the overexpression lines accumulated more Cd in the root tips and lateral root primordia compared with the wild-type. When grown in three Cd-contaminated paddy soils, overexpression of OsNRAMP5 decreased concentration of Cd in the grain by 49-94% compared with the wild type. OsNRAMP5-overexpression plants had decreased Cd translocation from roots to shoots as a result of disruption of its radial transport into the stele for xylem loading, demonstrating the effect of transporter localization and polarity on ion homeostasis.

Original languageEnglish
Pages (from-to)5705-5715
Number of pages11
JournalJournal of experimental botany
Volume71
Issue number18
DOIs
Publication statusPublished - Sep 19 2020
Externally publishedYes

Keywords

  • Cadmium (Cd)
  • Food safety
  • Manganese (Mn)
  • Oryza sativa
  • OsNRAMP5
  • Rice
  • Translocation
  • Transporter

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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