PHYTONUTRIENT BIOCHEMISTRY, PHYSIOLOGY, AND TRANSPORT
Location: Children Nutrition Research Center (Houston, Tx)
Title: Whole-plant mineral partitioning throughout the life cycle in Arabidopsis thaliana ecotypes Columbia, Landsberg erecta, Cape Verde Islands, and the mutant line ysl1ysl3
Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2007
Publication Date: January 1, 2008
Citation: Waters, B.M., Grusak, M.A. 2008. Whole-plant mineral partitioning throughout the life cycle in Arabidopsis thaliana ecotypes Columbia, Landsberg erecta, Cape Verde Islands, and the mutant line ysl1ysl3. New Phytologist. 177(2):389-405.
Interpretive Summary: Plants require several minerals for their successful growth. These minerals must also be deposited in developing seeds for use by the next generation of plants. In order to better understand how minerals move from soil, through the roots, to leaves, and then on to seeds, we quantified the distribution of minerals within plants throughout their entire life cycle. Using four diverse varieties of the model plant Arabidopsis, we identified which minerals are remobilized from leaves and leaf-like structures, and which minerals merely pass through these structures on their way to seeds. Our results are important because they provide an insight into which minerals require continued root absorption to ensure optimal delivery to developing seeds.
Minimal information exists on whole-plant dynamics of mineral flow through Arabidopsis thaliana or on the source tissues responsible for mineral export to developing seeds. Understanding these phenomena in a model plant could help in the development of nutritionally enhanced crop cultivars. A whole-plant partitioning study, using sequential harvests, was conducted to characterize growth and mineral concentrations and contents of rosettes, cauline leaves, stems, immature fruit, mature fruit hulls, and seeds of three WT lines (Col-0, Ler, and Cvi) and one mutant line (Col-0::ysl1ysl3). Shoot mineral content increased throughout the life cycle for all minerals, although tissue-specific mineral partitioning differed between genotypes. In particular, Fe, Zn, and Cu were aberrantly distributed in ysl1ysl3. Remobilization was observed for several minerals from various tissues, including cauline leaves and silique hulls, but the amounts were generally far below the total mineral accretion observed in seeds. When YSL1 and YSL3 are non-functional, Cu, Fe, and Zn are not effectively remobilized from, or do not effectively pass through, leaf and maternal fruit tissues. With respect to seed mineral accretion in Arabidopsis, continued uptake and translocation of minerals to source tissues during seed fill are as important, if not more important, than remobilization of previously stored minerals.