PHYTONUTRIENT BIOCHEMISTRY, PHYSIOLOGY, AND TRANSPORT
Location: Children Nutrition Research Center (Houston, Tx)
Title: Identification of polymorphisms in genes from the ZIP family of divalent metal transporters utilizing natural populations of Medicago truncatula
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2009
Publication Date: July 15, 2009
Citation: Stephens, B.W., Grusak, M.A., Mills, W.R. 2009. Identification of polymorphisms in genes from the ZIP family of divalent metal transporters utilizing natural populations of Medicago truncatula [abstract]. 2009 Model Legume Congress. p. 77.
Plants require divalent metal micronutrients, and these micronutrients must be obtained from the soil and redistributed throughout the plant in order to maintain optimal growth. The ability of plants to maintain micronutrient homeostasis is extremely important due to their participation in many diverse and essential processes. These processes are inhibited if an organism is unable to acquire sufficient micronutrients; however, these metals can be detrimental to organisms when present in excess, since several metals participate in redox reactions and can create reactive oxygen species (ROS). Therefore, their concentrations 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. We selected the ZIP family of divalent metal transporters, a family that includes members in plant, animal, and microbial species, all having similarity to the ZRT (zinc-regulated transporter) and IRT (iron-regulated transporter) genes from Saccharomyces cerevisiae. In Medicago truncatula, seven predicted ZIP proteins have been identified that transport divalent metals, but efforts are still underway to fully characterize their selectivities for different metals, and to understand each of their contributions to whole-plant metal homeostasis. Toward this end we have established a population of nearly 300 single plant lines (unique genotypes) of M. truncatula arising from accessions obtained through the USDA National Plant Germplasm System from collections maintained at the Western Regional Plant Introduction Station, Pullman, WA. These lines were grown for seed, and tissue was collected for isolation of genomic DNA to be analyzed for genotypic variation. The lines were screened for natural polymorphisms in regions of ZIP family genes including ZIP 1, 2 and 5. We will present information on the polymorphisms identified and the different haplotypes observed for these genes. In addition, mineral concentrations of seeds from each line will be discussed.