Biosynthesis of the halogenated auxin, 4-chloroindole-3-acetic acid

• Published in: http://www.plantphysiol.org Vol. 3
• Main Authors: Tivendale , Nathan D. (University of TasmaniaUniversity of Tasmania, TasmaniaTasmania(Australie). School of Plant ScienceSchool of Chemistry), Davidson , Sandra E. (University of Tasmania, Tasmania(Australie). School of Plant Science), Davies , Noel W. (University of Tasmania, Tasmania(Australie). Central Science Laboratory), Smith , Jason A. (University of Tasmania, Tasmania(Australie). School of Chemistry), Dalmais , Marion (INRA , Evry (France). UMR 1165 Génomique Végétale), Bendahmane , Abdelhafid (INRA , Evry (France). UMR 1165 Génomique Végétale), Quittenden , Laura J. (University of Tasmania, Tasmania(Australie). School of Plant Science), Sutton , Lily (University of Tasmania, Tasmania(Australie). School of Plant Science), Bala , Raj K. (University of Tasmania, Tasmania(Australie). School of Plant Science), Le Signor , Christine (INRA , Dijon (France). UMR 1347 Agroécologie), Thompson , Richard (INRA , Dijon (France). UMR 1347 Agroécologie), Horne , Jams (University of Tasmania, Tasmania(Australie). Central Science Laboratory), Reid , James B. (University of Tasmania, Tasmania(Australie). School of Plant Science), Ross , John J. (University of Tasmania, Tasmania(Australie). School of Plant Science)
• Format: Publication
• Language: English
• Published: 2012
• Subjects: aminotransférase; arabidopsis; biosynthèse; hormone végétale; maize; pea fruit; plant development; tryptophan

Seeds of several agriculturally important legumes are rich sources of the only halogenated plant hormone, 4-chloroindole-3-acetic acid. However, the biosynthesis of this auxin is poorly understood. Here, we show that in pea (Pisum sativum) seeds, 4-chloroindole-3-acetic acid is synthesized via the novel intermediate 4-chloroindole-3-pyruvic acid, which is produced from 4-chlorotryptophan by two aminotransferases, TRYPTOPHAN AMINOTRANSFERASE RELATED1 and TRYPTOPHAN AMINOTRANSFERASE RELATED2. We characterize a tar2 mutant, obtained by Targeting Induced Local Lesions in Genomes, the seeds of which contain dramatically reduced 4-chloroindole-3-acetic acid levels as they mature. We also show that the widespread auxin, indole-3-acetic acid, is synthesized by a parallel pathway in pea.