title: A rice ABC transporter, OsABCC1, reduces arsenic accumulation in the grain.
abstract: Arsenic (As) is a chronic poison that causes severe skin lesions and cancer. Rice (Oryza sativa L.) is a major dietary source of As; therefore, reducing As accumulation in the rice grain and thereby diminishing the amount of As that enters the food chain is of critical importance. Here, we report that a member of the Oryza sativa C-type ATP-binding cassette (ABC) transporter (OsABCC) family, OsABCC1, is involved in the detoxification and reduction of As in rice grains. We found that OsABCC1 was expressed in many organs, including the roots, leaves, nodes, peduncle, and rachis. Expression was not affected when plants were exposed to low levels of As but was up-regulated in response to high levels of As. In both the basal nodes and upper nodes, which are connected to the panicle, OsABCC1 was localized to the phloem region of vascular bundles. Furthermore, OsABCC1 was localized to the tonoplast and conferred phytochelatin-dependent As resistance in yeast. Knockout of OsABCC1 in rice resulted in decreased tolerance to As, but did not affect cadmium toxicity. At the reproductive growth stage, the As content was higher in the nodes and in other tissues of wild-type rice than in those of OsABCC1 knockout mutants, but was significantly lower in the grain. Taken together, our results indicate that OsABCC1 limits As transport to the grains by sequestering As in the vacuoles of the phloem companion cells of the nodes in rice.
authors.affiliation: Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea;
authors.forename: Won-Yong
authors.initials: WY
authors.lastname: Song
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan;
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yamaki
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan;
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamaji
authors.affiliation: Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea;
authors.forename: Donghwi
authors.initials: D
authors.lastname: Ko
authors.affiliation: Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea; and.
authors.forename: Ki-Hong
authors.initials: KH
authors.lastname: Jung
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan;
authors.forename: Miho
authors.initials: M
authors.lastname: Fujii-Kashino
authors.affiliation: Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea; and.
authors.forename: Gynheung
authors.initials: G
authors.lastname: An
authors.affiliation: Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea; Institute of Plant Biology, University Zurich, 8008 Zurich, Switzerland.
authors.forename: Enrico
authors.initials: E
authors.lastname: Martinoia
authors.affiliation: Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea; maj@rib.okayama-u.ac.jp ylee@postech.ac.kr.
authors.forename: Youngsook
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan; maj@rib.okayama-u.ac.jp ylee@postech.ac.kr.
authors.forename: Jian Feng
authors.initials: JF
authors.lastname: Ma
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis* / Q000235:genetics; D001151:Arsenic / Q000378:metabolism*; D001693:Biological Transport, Active / Q000235:genetics; D002104:Cadmium / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D012275:Oryza / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D052585:Phloem / Q000166:cytology / Q000378:metabolism; D012639:Seeds / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D018528:ATP-Binding Cassette Transporters; D002104:Cadmium; D001151:Arsenic
keywords: ABC transporter; arsenic; node; rice; vacuolar sequestration