Biosynthesis of the Halogenated Auxin, 4-Chloroindole-3-Acetic Acid

Nathan D. Tivendale, Sandra E. Davidson, Noel W. Davies, Jason A. Smith, Marion Dalmais, Abdelhafid I. Bendahmane, Laura J. Quittenden, Lily Sutton, Raj K. Bala, Christine Le Signor, Richard Thompson, James Horne, James B. Reid, John J. Ross

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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.

Original languageEnglish
Pages (from-to)1055-1063
Number of pages9
JournalPlant Physiology
Issue number3
Publication statusPublished - Jul 2012
Externally publishedYes

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