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Document Type

Campus Access

Degree Program

Plant Biology

Degree Type

Master of Science (M.S.)

Year Degree Awarded

2012

Month Degree Awarded

May

Keywords

Iron, Signaling, Maize, Arabidopsis, YSL

Abstract

Iron is an essential micronutrient that plays a role in essential processes in all living organisms. Because iron deficiency anemia is the number one human nutritional deficiency worldwide, research has been focused on studying biofortification, a method of plant breeding focused on increasing the nutrient content of the grain. In order to effectively implement this strategy, research to understand the molecular mechanisms surrounding iron uptake and maintenance within plants is necessary. A major goal of this work lies in exploring iron signaling in Arabidopsis thaliana and further characterization of the yellowstripe1-like1yellowstripe1-like3 (ysl1ysl3) double mutant plant. As shown here, iron signaling in arabidopsis appears to be regulated by a long distance signal derived in the shoots. The ysl1ysl3 double mutant is a plant shown to have severe mis-regulation of iron regulated genes. Here, I show ysl1ysl3 mutant plants are unable to respond to iron deficiency properly and lose signaling ability. It has been proposed that these defects are due to iron accumulation in the shoots but that appears untrue suggesting alternative functions for YSL1 and YSL3 in iron signaling. Another goal of the work included here seeks to elucidate alternative roles for ZmYS1 in maize outside of primary acquisition of iron from the soil. Here, ZmYS1 expression is shown via promoter::GUS analysis expressing throughout the shoot in many cell-types consistent with a role in the movement of iron between leaf tissues. Interestingly, expression in germinating seeds suggests ZmYS1 may also play a role in remobilization of stored iron in developing embryos.

First Advisor

Elsbeth L Walker

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