Cadmium transport and tolerance in rice: perspectives for reducing grain cadmium accumulation.

Shimpei Uraguchi,Toru Fujiwara

doi:10.1186/1939-8433-5-5

Abstract

Cadmium (Cd) is a toxic heavy metal which harms human health. In Japan, a major source of human Cd-intake is rice grains and contamination of paddy soils by Cd and accumulation of Cd in rice grains are the serious agricultural issues. There also exist Cd contamination of rice and its toxicity in several populations in countries including China and Thailand. Understanding the Cd transport mechanisms in rice can be a basis for regulating rice Cd transport and accumulation by molecular engineering and marker-assisted breeding. Recently, a number of studies have revealed the behavior of Cd in rice, genetic diversity of Cd accumulation, quantitative trait loci controlling Cd accumulation and transporter molecules regulating Cd accumulation and distribution in rice. In this article, we summarize recent advances in the field and discuss perspectives to reduce grain Cd contents.

Highlights

Cadmium (Cd) is a toxic heavy metal and is known as one of the major environmental pollutants
We describe current knowledge of rice Cd transporters and their roles in Cd accumulation
OsNramp1-overexpressing rice plants accumulated less Cd in roots and much Cd in shoots compared to the wild-type plants when grown in media containing 1 μM or less Cd, suggesting that OsNramp1 is possibly involved in Cd transport into roots

Summary

Introduction

Cadmium (Cd) is a toxic heavy metal and is known as one of the major environmental pollutants. These physiological studies indicate four major transport processes for rice Cd accumulation: (1) root Cd uptake, (2) root-to-shoot translocation by xylem flow, (3) redirection at nodes and (4) remobilization from leaves (Figure 1). OsNramp1-overexpressing rice plants accumulated less Cd in roots and much Cd in shoots compared to the wild-type plants when grown in media containing 1 μM or less Cd, suggesting that OsNramp1 is possibly involved in Cd transport into roots.

Results

Conclusion