Mutational reconstructed ferric chelate reductase confers enhanced tolerance in rice to iron deficiency in calcareous soil

Yasuhiro Ishimaru, Suyeon Kim, Takashi Tsukamoto, Hiroyuki Oki, Takanori Kobayashi, Satoshi Watanabe, Shinpei Matsuhashi, Michiko Takahashi, Hiromi Nakanishi, Satoshi Mori, Naoko K. Nishizawa

Research output: Contribution to journalArticlepeer-review

116 Citations (Scopus)

Abstract

Iron (Fe) deficiency is a worldwide agricultural problem on calcareous soils with low-Fe availability due to high soil pH. Rice plants use a well documented phytosiderophore-based system (Strategy II) to take up Fe from the soil and also possess a direct Fe2+ transport system. Rice plants are extremely susceptible to low-Fe supply, however, because of low phytosiderophore secretion and low Fe3+ reduction activity. A yeast Fe3+ chelate-reductase gene refre1/372, selected for better performance at high pH, was fused to the promoter of the Fe-regulated transporter, OslRT1, and introduced into rice plants. The transgene was expressed in response to a low-Fe nutritional status in roots of transformants. Transgenic rice plants expressing the refre1/372 gene showed higher Fe 3+ chelate-reductase activity and a higher Fe-uptake rate than vector controls under Fe-deficient conditions. Consequently, transgenic rice plants exhibited an enhanced tolerance to low-Fe availability and 7.9x the grain yield of nontransformed plants in calcareous soils. This report shows that enhancing the Fe3+ chelate-reductase activity of rice plants that normally have low endogenous levels confers resistance to Fe deficiency.

Original languageEnglish
Pages (from-to)7373-7378
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number18
DOIs
Publication statusPublished - 2007 May 1

Keywords

  • Chelate reductase
  • Fe-regulated transporter
  • Ferrous iron
  • Transgenic rice
  • Yeast Fe

ASJC Scopus subject areas

  • General

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