title: Subcellular targeting of bacterial CusF enhances Cu accumulation and alters root to shoot Cu translocation in arabidopsis.
abstract: Copper (Cu) is an important environmental pollutant that exerts harmful effects on all living organisms when in excess. In an effort to remove this toxin in situ, a bacterial Cu-binding protein gene CusF was engineered to target CusF for secretion to the cell wall and vacuoles and for accumulation in the cytoplasm. Analysis of transgenic Arabidopsis plants showed that CusF was functionally active and that plants expressing cell wall- (CusFcw transgenic lines) or vacuole-targeted CusF (CusFvac transgenic lines) were more resistant to Cu excess than untransformed plants and plants with cytoplasmic CusF (CusFcyto transgenic lines). Under short-term (48 h) exposure to Cu excess, CusFcw transgenic lines showed up to 2-fold increased Cu accumulation in roots compared with the untransformed plants; however, CusFcyto lines and the wild-type plants had similar Cu concentrations in both roots and shoots. Under long-term (40 d) exposure to Cu excess, all transgenic lines accumulated more Cu (up to 3-fold) in roots than the untransformed plants, whereas only CusFcyto lines showed a marked increase (∼3-fold of the wild-type plants) of Cu accumulation in shoots. In addition, expression of CusF in the cytosol dramatically enhanced Cu transport from roots to shoots when compared with plants with secretory pathway-targeted CusF. Our results demonstrate the feasibility of Cu tolerance and accumulation by engineering Cu-binding proteins targetable to subcellular compartments and provide new insights into the multifaceted mechanisms of Cu partitioning between roots and shoots.
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Pengli
authors.initials: P
authors.lastname: Yu
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Jinhong
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Department of Chemistry and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Deng
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Mi
authors.initials: M
authors.lastname: Ma
authors.affiliation: Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China hyz@ibcas.ac.cn.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D000079922:Copper Transport Proteins; D003600:Cytosol / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; C506213:CusF protein, E coli; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D003300:Copper
keywords: Arabidopsis; Cu accumulation; CusF; Phytoremediation; Subcellular targeting; Translocation factor