Auxins upregulate expression of the indole-3-pyruvate decarboxylase gene in Azospirillum brasilense.
Transcription of the Azospirillum brasilense ipdC gene, encoding an indole-3-pyruvate decarboxylase involved in the biosynthesis of indole-3-acetic acid (IAA), is induced by IAA as determined by ipdC-gusA expression studies and Northern analysis. Besides IAA, exogenously added synthetic auxins such as 1-naphthaleneacetic acid, 2,4-dichlorophenoxypropionic acid, and p-chlorophenoxyacetic acid were also found to upregulate ipdC expression. No upregulation was observed with tryptophan, acetic acid, or propionic acid or with the IAA conjugates IAA ethyl ester and IAA-L-phenylalanine, indicating structural specificity is required for ipdC induction. This is the first report describing the induction of a bacterial gene by auxin.
Vande Broek
A
A
F. A. Janssens Laboratory of Genetics, Katholieke Universiteit Leuven, B-3001 Heverlee, Belgium.
Lambrecht
M
M
Eggermont
K
K
Vanderleyden
J
J
D015806:Azospirillum brasilense / Q000166:cytology / Q000187:drug effects* / Q000235:genetics; D002262:Carboxy-Lyases / Q000096:biosynthesis* / Q000235:genetics; D015169:Colony Count, Microbial; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007210:Indoleacetic Acids / Q000494:pharmacology*; D012329:RNA, Bacterial / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015854:Up-Regulation