title: Accumulation and transformation of inorganic and organic arsenic in rice and role of thiol-complexation to restrict their translocation to shoot.
abstract: Environmental contamination of arsenic (As) and its accumulation in rice (Oryza sativa L.) is of serious human health concern. In planta speciation of As is an important tool to understand As metabolism in plants. In the present study, we investigated root to shoot As translocation and speciation in rice exposed to inorganic and methylated As. Arsenate (AsV) and methylarsonate (MAV) were efficiently reduced to arsenite (AsIII) and MAIII, respectively in rice root and shoot but no trivalent form of dimethylarsinate (DMAV) was detected. Further, up to 48 and 83% of root As in AsVand MAVexposed plants, respectively were complexed with various thiols showing up to 20 and 16 As species, respectively. Several mixed As- and MA-complexes with hydroxymethyl-phytochelatin, DesGly-phytochelatin, hydroxymethyl-GSH and cysteine were identified in rice. Despite high complexation in roots, more As was translocated to shoots in MAVexposed plants than AsV, with shoot/root As transfer factor being in order DMAV> MAV> AsV. Moreover, in shoots 78% MAIIIand 71% AsIIIwere present as weakly bound species which is alarming, as MAIIIhas been found to be more cytotoxic than AsIIIfor human and it could also be an important factor inducing straighthead (spikelet sterility disorder) in rice.
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstr. 15, D-04318 Leipzig, Germany.|CSIR-National Botanical Research Institute, Plant Ecology &Environmental Science Division, Rana Pratap Marg, Lucknow 226 001 (U.P.), India.
authors.forename: Seema
authors.initials: S
authors.lastname: Mishra
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstr. 15, D-04318 Leipzig, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Mattusch
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstr. 15, D-04318 Leipzig, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Wennrich
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D006801:Humans; D013058:Mass Spectrometry; D055432:Metabolomics / Q000379:methods; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D018520:Plant Shoots / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D013438:Sulfhydryl Compounds; D001151:Arsenic