title: Arsenic alters uptake and distribution of sulphur in Pteris vittata.
abstract: Low-molecular-weight thiol (LMWT) synthesis has been reported to be directly induced by arsenic (As) in Pteris vittata, an As hyperaccumulator. Sulphur (S) is a critical component of LMWTs. Here, the effect of As treatment on the uptake and distribution of S in P. vittata was investigated. In P. vittata grown under low S conditions, the presence of As in the growth medium enhanced the uptake of SO4(2-), which was used for LMWT synthesis in fronds. In contrast, As application did not affect SO4(2-) uptake in Nephrolepis exaltata, an As non-hyperaccumulator. Moreover, the isotope microscope system revealed that S absorbed with As accumulated locally in a vacuole-like organelle in epidermal cells, whereas S absorbed alone was distributed uniformly. These results suggest that S is involved in As transport and/or accumulation in P. vittata. X-ray absorption near-edge structure analysis revealed that the major As species in the fronds and roots of P. vittata were inorganic As(III) and As(V), respectively, and that As-LMWT complexes occurred as a minor species. Consequently, in case of As accumulation in P. vittata, S possibly acts as a temporary ligand for As in the form of LMWTs in intercellular and/or intracellular transport (e.g. vacuolar sequestration).
authors.affiliation: Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kitaku, Sapporo, 060-8589, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Watanabe
authors.forename: Ran
authors.initials: R
authors.lastname: Kouho
authors.forename: Tomo
authors.initials: T
authors.lastname: Katayose
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kitajima
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamaguchi
authors.forename: Takuro
authors.initials: T
authors.lastname: Shinano
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Yurimoto
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Osaki
mesh_terms: D001151:Arsenic / Q000494:pharmacology*; D001692:Biological Transport; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D032495:Pteris / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*; D013460:Sulfur Isotopes / Q000032:analysis
chemical_list: D012989:Soil Pollutants; D013438:Sulfhydryl Compounds; D013460:Sulfur Isotopes; D013455:Sulfur; D001151:Arsenic
keywords: hyperaccumulator; isotope microscope system; low-molecular-weight thiol; phytochelatin.