title: Genetic diversity of arsenic accumulation in rice and QTL analysis of methylated arsenic in rice grains.
abstract: BACKGROUND
  Rice is a major source of dietary intake of arsenic (As) for the populations that consume rice as a staple food. Therefore, it is necessary to reduce the As concentration in rice to avoid the potential risk to human health. In this study, the genetic diversity in As accumulation and As speciation in rice grains was investigated using a world rice core collection (WRC) comprising 69 accessions grown over a 3-year period. Moreover, quantitative trait locus (QTL) analysis was conducted to identify QTLs controlling the dimethylarsinic acid (DMA) content of rice grains.
  
  
  RESULTS
  There was a 3-fold difference in the grain As concentration of WRC. Concentrations of total-As, inorganic As, and DMA were significantly affected by genotype, year, and genotype-year interaction effects. Among the WRC accessions, Local Basmati and Tima (indica type) were identified as cultivars with the lowest stable total-As and inorganic As concentrations. Using an F2 population derived from Padi Perak (a high-DMA accession) and Koshihikari (a low-DMA cultivar), we identified two QTLs on chromosome 6 (qDMAs6.1 and qDMAs6.2) and one QTL on chromosome 8 (qDMAs8) that were responsible for variations in the grain DMA concentration. Approximately 73% of total phenotypic variance in DMA was explained by the three QTLs.
  
  
  CONCLUSIONS
  Based on the results provided, one strategy for developing rice cultivars with a low level of toxic As would be to change the proportion of organic As on the basis of a low level of total As content.
authors.affiliation: Soil Environment Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Kuramata
authors.affiliation: Soil Environment Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Abe
authors.affiliation: Soil Environment Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kawasaki
authors.affiliation: Genetic Resources Center, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Kaworu
authors.initials: K
authors.lastname: Ebana
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Shibaya
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
authors.affiliation: Soil Environment Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan. isatoru@affrc.go.jp.
authors.forename: Satoru
authors.initials: S
authors.lastname: Ishikawa