Waters, Brian M. , Grusak, Michael A. .
Dynamic mineral partitioning in diverse Arabidopsis thaliana accessions; the ysl1ysl3 mutant fails to distribute Cu, Fe, and Zn normally in vegetative tissues, fruits, and seeds.
Arabidopsis thaliana has been used as a model to elucidate mechanisms of mineral uptake and homeostasis. We and others are interested in using the information gained from arabidopsis studies to improve mineral concentration in edible portions of crop plants, a strategy known as biofortification. To identify source tissues for seed minerals, a sequential partitioning study of three wild-type lines (Columbia-0, Landsberg erecta, and Cape Verde Islands) and one mutant line (ysl1ysl3) which has low seed Cu, Fe, and Zn concentrations was conducted. This work describes growth dynamics of these lines, as well as the dynamics of mineral (Ca, Cu, Fe, K, Mg, Mn, P, S, and Zn) concentrations and contents in rosettes, cauline leaves, stems, immature fruits, mature fruit hulls, and seeds. Our results suggest that vegetative tissues can supply minerals to seeds by remobilization during leaf senescence, however, this process is of less importance than continued uptake from the rhizosphere and passage through source tissues during seed development. There were partitioning differences for several minerals amongst the genotypes, suggesting genetic influence. Use of the ysl1ysl3 mutant demonstrated that Fe, Zn, and especially Cu, are aberrantly distributed within shoot tissues, and the mutant has lower total plant Fe and higher total plant Cu. In rosettes, cauline leaves, and silique hulls, ysl1ysl3 Cu and Zn partitioning is significantly higher than WT, however, stem, immature fruit and seed Cu, Fe, and Zn concentrations are significantly lower than WT. These results demonstrate that Cu, Fe, and Zn are not being properly remobilized from or moved through leaf and maternal fruit tissues in the double mutant. This research was supported by funds from HarvestPlus to MAG.
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1 - USDA-ARS/Baylor College of Medicine Children's Nutrition Research Cen, Pediatrics-Nutrition, 1100 Bates St., Houston, Texas, 77030, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM