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Defining the expression domains of the Arabidopsis glutaredoxin genes AtGRXS5 , AtGRXS6 , and AtGRXS8
Author(s) -
Davalos Oscar,
Ehrary Ahmad,
Rosas Miguel,
Fernandez Francisco,
Escobar Matthew A.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.533.69
Subject(s) - glutaredoxin , arabidopsis , arabidopsis thaliana , biology , gene , gene expression , reporter gene , promoter , microbiology and biotechnology , regulation of gene expression , genetics , thioredoxin , mutant
Glutaredoxins are oxidoreductase enzymes that can regulate the activities of target proteins through the reversible breakage of disulfide bonds. We recently identified a group of seven glutaredoxin genes that are upregulated by nitrate and control primary root length in the model plant Arabidopsis thaliana . The objective of this study was to characterize the gene expression patterns and subcellular localization of three nitrate‐regulated glutaredoxins: AtGRXS5 , AtGRXS6 , and AtGRXS8 . Reporter lines consisting of the glutaredoxin promoter sequences fused to the β‐glucuronidase (GUS) gene were used to study glutaredoxin gene expression. Colorimetric GUS assays and histological sectioning showed that AtGRXS5 , AtGRXS6 , and AtGRXS8 are expressed exclusively in the phloem of A. thaliana roots and leaves. GUS activity assays demonstrated that AtGRXS6 and AtGRXS8 are strongly and specifically upregulated by nitrate. In contrast, AtGRXS5 gene expression was activated by both ammonium and nitrate. Nitrate concentrations as low as 50 μM activated glutaredoxin gene expression, with no further increase in expression at higher concentrations of nitrate. To characterize the subcellular localization of AtGRXS5 , AtGRXS6 , and AtGRXS8 , translational fusions between the glutaredoxin gene and yellow fluorescent protein (YFP) were expressed in transgenic Arabidopsis and tobacco ( Nicotiana benthamiana ) plants. Preliminary results demonstrated that all three glutaredoxins are localized to cell nuclei as well as small, yet unidentified structures in the cytoplasm. Overall, these studies will further explain how plants control the growth of their root system to maximize the uptake of nitrogen from the soil, a behavioral response that is highly significant in agriculture. Support or Funding Information NSF IOS grant 1651584NIH RISE GM‐64783 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .