A plasma membrane zinc transporter from Medicago truncatula is up-regulated in roots by Zn fertilization, yet down-regulated by arbuscular mycorrhizal colonization

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T1 - A plasma membrane zinc transporter from Medicago truncatula is up-regulated in roots by Zn fertilization, yet down-regulated by arbuscular mycorrhizal colonization

AU - Burleigh, Stephen

AU - Kristensen, B K

AU - Bechmann, I E

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Microbial Ecology (Closed 2011) (011008001)

PY - 2003

Y1 - 2003

N2 - Here we present a Zn transporter cDNA named MtZIP2 from the model legume Medicago truncatula. MtZIP2 encodes a putative 37 kDa protein with 8-membrane spanning domains and has moderate amino acid identity with the Arabidopsis thaliana Zn transporter AtZIP2p. MtZIP2 complemented a Zn-uptake mutant of yeast implying that the protein encoded by this gene can transport Zn across the yeast's plasma membrane. The product of a MtZIP2-GFP fusion construct introduced into onion cells by particle bombardment likewise localized to the plasma membrane. The MtZIP2 gene was expressed in roots and stems, but not in leaves of M. truncatula and, in contrast to all other plant Zn transporters characterized thus far, MtZIP2 was up-regulated in roots by Zn fertilization. Expression was highest in roots exposed to a toxic level of Zn. MtZIP2 expression was also examined in the roots of M. truncatula when colonized by the obligate plant symbiont, arbuscular mycorrhizal (AM) fungi, since AM fungi are renowned for their ability to supply plants with mineral nutrients, including Zn. Expression was downregulated in the roots of the mycorrhizal plants and was associated with a reduced level of Zn within the host plant tissues.

AB - Here we present a Zn transporter cDNA named MtZIP2 from the model legume Medicago truncatula. MtZIP2 encodes a putative 37 kDa protein with 8-membrane spanning domains and has moderate amino acid identity with the Arabidopsis thaliana Zn transporter AtZIP2p. MtZIP2 complemented a Zn-uptake mutant of yeast implying that the protein encoded by this gene can transport Zn across the yeast's plasma membrane. The product of a MtZIP2-GFP fusion construct introduced into onion cells by particle bombardment likewise localized to the plasma membrane. The MtZIP2 gene was expressed in roots and stems, but not in leaves of M. truncatula and, in contrast to all other plant Zn transporters characterized thus far, MtZIP2 was up-regulated in roots by Zn fertilization. Expression was highest in roots exposed to a toxic level of Zn. MtZIP2 expression was also examined in the roots of M. truncatula when colonized by the obligate plant symbiont, arbuscular mycorrhizal (AM) fungi, since AM fungi are renowned for their ability to supply plants with mineral nutrients, including Zn. Expression was downregulated in the roots of the mycorrhizal plants and was associated with a reduced level of Zn within the host plant tissues.

U2 - 10.1023/A:1025479701246

DO - 10.1023/A:1025479701246

M3 - Article

VL - 52

SP - 1077

EP - 1088

JO - Plant Molecular Biology

JF - Plant Molecular Biology

SN - 1573-5028

IS - 5

ER -