title: Characterization of two genes encoding metal tolerance proteins from Beta vulgaris subspecies maritima that confers manganese tolerance in yeast.
abstract: Manganese (Mn(2+)) is an essential micronutrient in plants. However increased Mn(2+) levels are toxic to plant cells. Metal tolerance proteins (MTPs), member of cation diffusion facilitator protein (CDF) family, have important roles in metal homeostatis in different plant species and catalyse efflux of excess metal ions. In this study, we identified and characterized two MTP genes from Beta vulgaris spp. maritima (B. v. ssp. maritima). Overexpression of these two genes provided Mn tolerance in yeast cells. Sequence analyses displayed BmMTP10 and BmMTP11 as members of the Mn-CDF family. Functional analyses of these proteins indicated that they are specific to Mn(2+) with a role in reducing excess cellular Mn(2+) levels when expressed in yeast. GFP-fusion constructs of both proteins localized to the Golgi apparatus as a punctuated pattern. Finally, Q-RT-PCR results showed that BmMTP10 expression was induced threefold in response to the excess Mn(2+) treatment. On the other hand BmMTP11 expression was not affected in response to excess Mn(2+) levels. Thus, our results suggest that the BmMTP10 and BmMTP11 proteins from B. v. ssp. maritima have non-redundant functions in terms of Mn(2+) detoxification with a similar in planta localization and function as the Arabidopsis Mn-CDF homolog AtMTP11 and this conservation shows the evolutionary importance of these vesicular proteins in heavy metal homeostatis among plant species.
authors.affiliation: Department of Molecular Biology and Genetics, Izmir Institute of Technology, 35430, Urla, Izmir, Turkey.
authors.forename: Isil
authors.initials: I
authors.lastname: Erbasol
authors.forename: Gonensin Ozan
authors.initials: GO
authors.lastname: Bozdag
authors.forename: Ahmet
authors.initials: A
authors.lastname: Koc
authors.forename: Pai
authors.initials: P
authors.lastname: Pedas
authors.forename: Huseyin Caglar
authors.initials: HC
authors.lastname: Karakaya
mesh_terms: D000595:Amino Acid Sequence; D027461:Beta vulgaris / Q000235:genetics*; D008658:Inactivation, Metabolic; D008345:Manganese / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D008345:Manganese