ARS | Publication request: Comparisons of polymorphisms in MtZIP1 isolated from natural populations of medicago truncatula

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2010
Publication Date: July 2, 2010
Citation: Stephens, B.W., Grusak, M.A., Mills, W.R. 2010. Comparisons of polymorphisms in MtZIP1 isolated from natural populations of medicago truncatula [abstract]. Vth International Congress on Legume Genetics and Genomics. p. 124.

Technical Abstract: The divalent metal zinc (Zn) is required by plants and must be obtained from the soil and redistributed throughout the plant in order to maintain optimal growth. The ability of plants to maintain Zn homeostasis is important due to its participation in many diverse and essential processes. These processes are inhibited if an organism is unable to maintain adequate Zn concentrations; however, Zn can be detrimental to organisms when present in excess. Therefore, the concentration of Zn must be controlled by transporters that are responsible for uptake, efflux, and compartmentalization within the plant. There are several families of metal transporters responsible for maintaining homeostasis within the plant. The ZIP transporters are one family of divalent metal transporters that includes members in plant, animal, and microbial species, with all having similarity to the ZRT (zinc-regulated transporter) and IRT (iron-regulated transporter) genes from Saccharomyces cerevisiae. In Medicago truncatula, four predicted ZIP proteins have been identified that transport Zn (MtZIP1, MtZIP2, MtZIP5, and MtZIP6). MtZIP1, MtZIP5, and MtZIP6 have been characterized for their affinity for Zn, and it was determined that MtZIP1 is a low affinity transporter (Km = 1 uM) and MtZIP5 and MtZIP6 are high affinity transporters (Km = 0.3 uM and 0.4 uM, respectively) Furthermore, we have identified 9 haplotypes of MtZIP1 from a population of approximately 300 single plant lines (unique genotypes) of M. truncatula, arising from accessions obtained through the USDA National Plant Germplasm System (NPGS) from collections maintained at the Western Regional Plant Introduction Station, Pullman WA. We are currently cloning these 9 haplotypes for transformation into the Zn transport deficient mutant ZHY3 for complementation studies.