Title

Plastid-Targeted Iron-Sulfur Carrier Proteins in Arabidopsis Thaliana

Date of Award

4-2019

Degree Name

Master of Science

Department

Biological Sciences

First Advisor

Dr. Yan Lu

Second Advisor

Dr. Silvia Rossbach

Third Advisor

Dr. Todd J. Barkman

Keywords

plastid-targeted, iron-sulfur carrier proteins, Arabidopsis thaliana

Access Setting

Masters Thesis-Abstract Only

Restricted to Campus until

4-2029

Abstract

To ensure the functionality of many vital processes such as photosynthesis and respiration, plants have a high iron and sulfur demand. Iron and sulfur are essential elements for all photosynthetic organisms. Examples of the common Fe-S clusters found in plant proteins include classic 2Fe-2S, Rieske-type 2Fe-2S, 3Fe-4S, and 4Fe-4S clusters. Fe-S cluster assembly and transfer requires the participation of NFU proteins, which act as Fe-S carriers in plastids and mitochondria. Each NFU protein contains a redox-active NFU domain of 60 amino acids with two highly conserved cysteine residues. The nuclear genome of Arabidopsis encodes five NFU proteins. NFU1, NFU2, and NFU3 are plastid targeted, but NFU4 and NFU5 are mitochondria targeted. As both NFU2 and NFU3 participate in the assembly and transfer of 4Fe-4S cluster, we hypothesize that NFU2 and NFU3 have overlapping yet distinct functions. To analyze the functional redundancy between NFU2 and NFU3 proteins, we characterized nfu2/nfu2 (Homozygous) NFU3/nfu3 (Heterozygous) and NFU2/nfu2 (Heterozygous) nfu3/nfu3 (Homozygous) plants. These mutants have smaller plant and leaf sizes, lower chlorophyll contents, and lower PSI and PSII activities than the single mutants. The results of this study indicate that simultaneous mutations in NFU2 and NFU3 genes have an additive effect and NFU1 plays a minor role in the biogenesis of Fe-S cluster in the plastid.

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