title: Cucumber metal transport protein MTP8 confers increased tolerance to manganese when expressed in yeast and Arabidopsis thaliana.
abstract: Cation diffusion facilitator (CDF) proteins are ubiquitous divalent cation transporters that have been proved to be essential for metal homeostasis and tolerance in Archaebacteria, Bacteria, and Eukaryota. In plants, CDFs are designated as metal tolerance proteins (MTPs). Due to the lack of genomic resources, studies on MTPs in other plants, including cultivated crops, are lacking. Here, the identification and organization of genes encoding members of the MTP family in cucumber are described. The first functional characterization of a cucumber gene encoding a member of the Mn-CDF subgroup of CDF proteins, designated as CsMTP8 based on the highest homology to plant MTP8, is also presented. The expression of CsMTP8 in Saccharomyces cerevisiae led to increased Mn accumulation in yeast cells and fully restored the growth of mutants hypersensitive to Mn in Mn excess. Similarly, the overexpression of CsMTP8 in Arabidopsis thaliana enhanced plant tolerance to high Mn in nutrition media as well as the accumulation of Mn in plant tissues. When fused to green fluorescent protein (GFP), CsMTP8 localized to the vacuolar membranes in yeast cells and to Arabidopsis protoplasts. In cucumber, CsMTP8 was expressed almost exclusively in roots, and the level of gene transcript was markedly up-regulated or reduced under elevated Mn or Mn deficiency, respectively. Taken together, the results suggest that CsMTP8 is an Mn transporter localized in the vacuolar membrane, which participates in the maintenance of Mn homeostasis in cucumber root cells.
authors.affiliation: Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland mmigocka@biol.uni.wroc.pl.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Migocka
authors.affiliation: Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Papierniak
authors.affiliation: Wrocław University, Institute of Experimental Biology, Department of Genetics and Cell Physiology, Kanonia 6/8, 50-328 Wrocław, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Maciaszczyk-Dziubińska
authors.affiliation: Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Poździk
authors.affiliation: Wrocław University, Institute of Experimental Biology, Department of Molecular Plant Physiology, Kanonia 6/8, 50-328 Wrocław, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Posyniak
authors.affiliation: Wrocław University, Institute of Experimental Biology, Department of Animal Developmental Biology, Sienkiewicza 21, 50-335 Wrocław, Poland.
authors.forename: Arnold
authors.initials: A
authors.lastname: Garbiec
authors.affiliation: Institut des Sciences du Végétal, CNRS, 1 Avenue de la Terrasse, Saclay Plant Sciences Labex, 91198 Gif-Sur-Yvette Cedex, France Université Paris 7-Denis Diderot, UFR Sciences du Vivant, Saclay Plant Sciences Labex, 91198 Gif-Sur-Yvette Cedex, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Filleur
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018553:Cucumis sativus / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008345:Manganese / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*
chemical_list: D027682:Cation Transport Proteins; D010940:Plant Proteins; D008345:Manganese
keywords: CDF (cation diffusion facilitator) family; Cucumis sativus; MTP (metal tolerance protein) family; heavy metals; metal homeostasis; tonoplast.