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United States Department of Agriculture

Agricultural Research Service

Title: Characterization of a zinc transport mutant and its role in zinc homeostasis in the model legume Medicago truncatula

Authors
item Stephens, Brian -
item Cook, Douglas -
item Grusak, Michael

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2009
Publication Date: July 14, 2009
Citation: Stephens, B.W., Cook, D.R., Grusak, M.A. 2009. Characterization of a zinc transport mutant and its role in zinc homeostasis in the model legume Medicago truncatula [abstract]. 2009 Model Legume Congress. p. 76.

Technical Abstract: Zinc is an essential micronutrient required by plants that must be obtained from the soil and redistributed throughout the plant in order to maintain optimal growth. The ability of plants to maintain zinc homeostasis is extremely important due to the participation of zinc in diverse and essential processes that are required for growth and normal development. These processes are inhibited if plants are unable to acquire sufficient zinc; however, zinc can also be detrimental to organisms when present in excess. Therefore, zinc concentration must be regulated by zinc transporters that are responsible for uptake, efflux, and compartmentalization of zinc within the plant to maintain proper balance of zinc within the plant. To increase our understanding of zinc homeostasis in plants, we have isolated a mutant from Medicago truncatula that shows zinc deficiency symptoms that include shortened internodal length, small leaves and a decrease in fertility (seed set). The effect of the mutation on the whole plant partitioning of zinc and cadmium between the roots and vegetative tissues will be discussed. Phenotypic characteristics of the mutant will be compared to the characteristics of A17, including: biomass, yield, and mineral analysis. The effect of the mutation on ZIP gene expression will be shown in plants grown on zinc concentrations maintained at normal levels (1 uM) or at concentrations that induce zinc deficiency (0 uM) or toxicity (10 uM). Finally, a model of how the mutant functions in whole-plant metal homeostasis will be presented.

Last Modified: 7/25/2014
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