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Arabidopsis AtGSTF2 is regulated by ethylene and auxin, and encodes a glutathione S‐transferase that interacts with flavonoids
Author(s) -
Smith Aaron P.,
Nourizadeh Saeid D.,
Peer Wendy A.,
Xu Jinghuai,
Bandyopadhyay Anindita,
Murphy Angus S.,
Goldsbrough Peter B.
Publication year - 2003
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2003.01890.x
Subject(s) - auxin , arabidopsis , biochemistry , arabidopsis thaliana , glutathione , polar auxin transport , mutant , microbiology and biotechnology , wild type , biology , chemistry , gene , enzyme
Summary Expression of the Arabidopsis glutathione S‐transferase (GST) gene AtGSTF2 is induced by several stimuli, but the function of this GST remains unknown. We demonstrate that AtGSTF2 expression is also induced by glutathione, paraquat, copper, and naphthalene acetic acid (NAA) via a mechanism independent of ethylene perception, as determined by analysis of the ethylene‐insensitive etr1 mutant. Deletion analyses identified two promoter regions important for regulation of AtGSTF2 expression in response to several of these inducers. Previous studies have suggested that At GSTF2 interacts with indole‐3‐acetic acid (IAA) and the auxin transport inhibitor 1‐ N ‐naphthylphthalamic acid (NPA). We show that recombinant At GSTF2 directly binds IAA, NPA, and the artificial auxin NAA. As NPA may act as an endogenous flavonoid regulator of auxin transport, competition between NPA and flavonoids for binding to At GSTF2 was examined. Both quercetin and kaempferol competed with NPA for At GSTF2 binding, indicating that all three compounds bind At GSTF2 at the same site. In transgenic Arabidopsis seedlings, AtGSTF2::GUS expression occurred at the root–shoot transition zone and was induced in this region, as well as at the root distal elongation zone, after treatment with IAA. In wild‐type seedlings, At GSTF2 is localized near the plasma membrane of cells in the root–shoot transition zone. However, both AtGSTF2::GUS expression and localization of At GSTF2 protein were disrupted in flavonoid‐deficient tt4 seedlings. Our results indicate that At GSTF2 is involved not only in stress responses but also in development under normal growth conditions.