Physiological, genetic, and molecular characterization of a high-Cd-accumulating rice cultivar, Jarjan

Daisei Ueno, Emi Koyama, Naoki Yamaji, Jian Feng Ma

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

Cadmium (Cd) in rice is a major source of Cd intake for people on a staple rice diet. The mechanisms underlying Cd accumulation in rice plant are still poorly understood. Here, we characterized the physiology and genetics of Cd transport in a high-Cd-accumulating cultivar (Jarjan) of rice (Oryza sativa). Jarjan showed 5- to 34-fold higher Cd accumulation in the shoots and grains than the cultivar Nipponbare, when it was grown in either a non-Cd-contaminated or a Cd-contaminated soil. A short-term uptake experiment showed no significant difference in Cd uptake by the roots between the two cultivars. However, Jarjan translocated 49% of the total Cd taken up to the shoots, whereas Nipponbare retained most of the Cd in the roots. In both concentration- and time-dependent experiments, Jarjan showed a superior capacity for root-to-shoot translocation of Cd. These results indicate that the high-Cd-accumulation phenotype in Jarjan results from efficient translocation of Cd from roots to shoots. Genetic analysis using an F2 population derived from Jarjan and Nipponbare revealed that plants showing high- and low-Cd-accumulation phenotypes segregated in a 1:3 ratio, indicating that high accumulation in Jarjan is controlled by a single recessive gene. Furthermore, we isolated OsHMA3, a gene encoding a tonoplast-localized Cd transporter from Jarjan. The OsHMA3 protein was localized in all roots cells, but the sequence has a mutation leading to loss of function. Therefore, failure to sequester Cd into the root vacuoles by OsHMA3 is probably responsible for high Cd accumulation in Jarjan.

Original languageEnglish
Pages (from-to)2265-2272
Number of pages8
JournalJournal of experimental botany
Volume62
Issue number7
DOIs
Publication statusPublished - Apr 1 2011

Keywords

  • Cadmium accumulation
  • OsHMA3
  • rice
  • sequestration
  • transport
  • vacuole

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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