title: Paraquat Resistant1, a Golgi-localized putative transporter protein, is involved in intracellular transport of paraquat.
abstract: Paraquat is one of the most widely used herbicides worldwide. In green plants, paraquat targets the chloroplast by transferring electrons from photosystem I to molecular oxygen to generate toxic reactive oxygen species, which efficiently induce membrane damage and cell death. A number of paraquat-resistant biotypes of weeds and Arabidopsis (Arabidopsis thaliana) mutants have been identified. The herbicide resistance in Arabidopsis is partly attributed to a reduced uptake of paraquat through plasma membrane-localized transporters. However, the biochemical mechanism of paraquat resistance remains poorly understood. Here, we report the identification and characterization of an Arabidopsis paraquat resistant1 (par1) mutant that shows strong resistance to the herbicide without detectable developmental abnormalities. PAR1 encodes a putative l-type amino acid transporter protein localized to the Golgi apparatus. Compared with the wild-type plants, the par1 mutant plants show similar efficiency of paraquat uptake, suggesting that PAR1 is not directly responsible for the intercellular uptake of paraquat. However, the par1 mutation caused a reduction in the accumulation of paraquat in the chloroplast, suggesting that PAR1 is involved in the intracellular transport of paraquat into the chloroplast. We identified a PAR1-like gene, OsPAR1, in rice (Oryza sativa). Whereas the overexpression of OsPAR1 resulted in hypersensitivity to paraquat, the knockdown of its expression using RNA interference conferred paraquat resistance on the transgenic rice plants. These findings reveal a unique mechanism by which paraquat is actively transported into the chloroplast and also provide a practical approach for genetic manipulations of paraquat resistance in crops.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry and National Plant Gene Research Center, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Jianyong
authors.initials: J
authors.lastname: Li
authors.forename: Jinye
authors.initials: J
authors.lastname: Mu
authors.forename: Jiaoteng
authors.initials: J
authors.lastname: Bai
authors.forename: Fuyou
authors.initials: F
authors.lastname: Fu
authors.forename: Tingting
authors.initials: T
authors.lastname: Zou
authors.forename: Fengying
authors.initials: F
authors.lastname: An
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Hongwei
authors.initials: H
authors.lastname: Jing
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Shuhua
authors.initials: S
authors.lastname: Yang
authors.forename: Jianru
authors.initials: J
authors.lastname: Zuo
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D002874:Chromosome Mapping; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006056:Golgi Apparatus / Q000378:metabolism*; D053209:Herbicide Resistance; D006540:Herbicides / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000235:genetics / Q000378:metabolism; D010269:Paraquat / Q000378:metabolism*; D010641:Phenotype; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D002734:Chlorophyll; D006540:Herbicides; D010269:Paraquat; C524961:PAR1 protein, Arabidopsis