title: Engineering metal-binding sites of bacterial CusF to enhance Zn/Cd accumulation and resistance by subcellular targeting.
abstract: The periplasmic protein CusF acts as a metallochaperone to mediate Cu resistance in Escherichia coli. CusF does not contain cysteine residues and barely binds to divalent cations. Here, we addressed effects of cysteine-substitution mutant (named as mCusF) of CusF on zinc/cadmium (Zn/Cd) accumulation and resistance. We targeted mCusF to different subcellular compartments in Arabidopsis. We found that plants expressing vacuole-targeted mCusF were more resistant to excess Zn than WT and plants with cell wall-targeted or cytoplasmic mCusF. Under long-term exposure to excess Zn, all transgenic lines accumulated more Zn (up to 2.3-fold) in shoots than the untransformed plants. Importantly, plants with cytoplasmic mCusF showed higher efficiency of Zn translocation from root to shoot than plants with secretory pathway-targeted-mCusF. Furthermore, the transgenic lines exhibited enhanced resistance to Cd and significant increase in root-to-shoot Cd translocation. We also found all transgenic plants greatly improved manganese (Mn) and iron (Fe) homeostasis under Cd exposure. Our results demonstrate heterologous expression of mCusF could be used to engineer a new phytoremediation strategy for Zn/Cd and our finding also deepen our insights into mechanistic basis for relieving Cd toxicity in plants through proper root/shoot partitioning mechanism and homeostatic accumulation of Mn and Fe.
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: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, United States.
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. Electronic address: hyz@ibcas.ac.cn.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D000079922:Copper Transport Proteins; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005818:Genetic Engineering; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000378:metabolism*; D013312:Stress, Physiological; D015032:Zinc / Q000378:metabolism*
chemical_list: D027682:Cation Transport Proteins; D000079922:Copper Transport Proteins; C506213:CusF protein, E coli; D029968:Escherichia coli Proteins; D002104:Cadmium; D015032:Zinc
keywords: Cadmium (Cd); CusF; Cysteine; Subcellular targeting; Zinc (Zn)