title: Natural variation in a polyamine transporter determines paraquat tolerance in Arabidopsis.
abstract: Polyamines (PAs) are ubiquitous, polycationic compounds that are essential for the growth and survival of all organisms. Although the PA-uptake system plays a key role in mammalian cancer and in plant survival, the underlying molecular mechanisms are not well understood. Here, we identified an Arabidopsis L-type amino acid transporter (LAT) family transporter, named RMV1 (resistant to methyl viologen 1), responsible for uptake of PA and its analog paraquat (PQ). The natural variation in PQ tolerance was determined in 22 Arabidopsis thaliana accessions based on the polymorphic variation of RMV1. An RMV1-GFP fusion protein localized to the plasma membrane in transformed cells. The Arabidopsis rmv1 mutant was highly resistant to PQ because of the reduction of PQ uptake activity. Uptake studies indicated that RMV1 mediates proton gradient-driven PQ transport. RMV1 overexpressing plants were hypersensitive to PA and PQ and showed elevated PA/PQ uptake activity, supporting the notion that PQ enters plant cells via a carrier system that inherently functions in PA transport. Furthermore, we demonstrated that polymorphic variation in RMV1 controls PA/PQ uptake activity. Our identification of a molecular entity for PA/PQ uptake and sensitivity provides an important clue for our understanding of the mechanism and biological significance of PA uptake.
authors.affiliation: Gene Discovery Research Group,  RIKEN Plant Science Center, Tsukuba, Ibaraki 305-0074,  Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Fujita
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Fujita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iuchi
authors.forename: Kohji
authors.initials: K
authors.lastname: Yamada
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Urano
authors.forename: Masatomo
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yamaguchi-Shinozaki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010269:Paraquat / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011073:Polyamines / Q000378:metabolism* / Q000494:pharmacology; D020641:Polymorphism, Single Nucleotide; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; D026901:Membrane Transport Proteins; D011073:Polyamines; C573329:RMV1 protein, Arabidopsis; D049452:Green Fluorescent Proteins; D010269:Paraquat