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Title: Arabidopsis glutaredoxin s17 contributes to vegetative growth, mineral accumulation, and redox balance during iron deficiency

item YU, HAN - Baylor College Of Medicine
item YANG, JIAN - Baylor College Of Medicine
item SHI, YA-FEI - Zhejiang Normal University
item DONELSON, JIMMONIQUE - Baylor College Of Medicine
item THOMPSON, SEAN - Texas A&M University
item SPRAGUE, STUART - Kansas State University
item ROSHAN, TONY - Baylor College Of Medicine
item WANG, DA-LI - Zhejiang Normal University
item LIU, JIANZHONG - Zhejiang Normal University
item PARK, SUNGHUN - Kansas State University
item Nakata, Paul
item CONNOLLY, ERIN - Pennsylvania State University
item HIRSCHI, KENDAL - Children'S Nutrition Research Center (CNRC)
item Grusak, Michael
item CHENG, NINGHUI - Children'S Nutrition Research Center (CNRC)

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2017
Publication Date: 5/31/2017
Citation: Yu, H., Yang, J., Shi, Y., Donelson, J., Thompson, S.M., Sprague, S., Roshan, T., Wang, D., Liu, J., Park, S., Nakata, P.A., Connolly, E.L., Hirschi, K.D., Grusak, M.A., Cheng, N. 2017. Arabidopsis glutaredoxin s17 contributes to vegetative growth, mineral accumulation, and redox balance during iron deficiency. Frontiers in Plant Science. doi:10.3389/fpls.2017.01045.

Interpretive Summary: Iron is an essential mineral nutrient for plants. It serves as an important metal cofactor in hundreds of metabolic enzymes that function in respiration and photosynthesis. Iron stress, either iron deficiency or iron excess, can lead to toxic conditions in the plant cell, reduction of growth and organ development, and eventually reduced crop yield. Therefore, we have been interested in understanding how iron status in the plant is sensed, and how this helps the plant to absorb appropriate levels of iron to meet all of its metabolic and storage needs. In this work, we have studied how a particular protein is involved in regulating the oxidative state of cells, which in turn has an influence on the iron requirements of those cells. We have used plants defective in this protein, or plants that overproduce this protein, to assess the impact of these changes on iron acquisition processes in the roots and throughout the plant. Our results indicate that this protein may be an important component of the plant's iron regulatory mechanisms.

Technical Abstract: Iron (Fe) is an essential mineral nutrient and a metal cofactor required for many proteins and enzymes involved in the processes of DNA synthesis, respiration, and photosynthesis. Iron limitation can have detrimental effects on plant growth and development. Such effects are mediated, at least in part, through the generation of reactive oxygen species (ROS). Thus, plants have evolved a complex regulatory network to respond to conditions of iron limitations. However, the mechanisms that couple iron deficiency and oxidative stress responses are not fully understood. Here, we report the discovery that an Arabidopsis thaliana monothiol glutaredoxin S17 (AtGRXS17) plays a critical role in the plants ability to respond to iron deficiency stress and maintain redox homeostasis. In a yeast expression assay, AtGRXS17 was able to suppress the iron accumulation in yeast ScGrx3/ScGrx4 mutant cells. Genetic analysis indicated that plants with reduced AtGRXS17 expression were hypersensitive to iron deficiency and showed increased iron concentrations in mature seeds. Disruption of AtGRXS17 caused plant sensitivity to exogenous oxidants and increased ROS production under iron deficiency. Addition of reduced glutathione rescued the growth and alleviates the sensitivity of atgrxs17 mutants to iron deficiency. These findings suggest AtGRXS17 helps integrate redox homeostasis and iron deficiency responses.