CYP83B1, a cytochrome P450 at the metabolic branch point in auxin and indole glucosinolate biosynthesis in Arabidopsis

S. Bak, F. E. Tax, K. A. Feldmann, D. W. Galbraith, R. Feyereisen

Research output: Contribution to journalArticle

271 Scopus citations

Abstract

Auxins are growth regulators involved in virtually all aspects of plant development. However, little is known about how plants synthesize these essential compounds. We propose that the level of indole-3-acetic acid is regulated by the flux of indole-3-acetaldoxime through a cytochrome P450, CYP83B1, to the glucosinolate pathway. A T-DNA insertion in the CYP83B1 gene leads to plants with a phenotype that suggests severe auxin overproduction, whereas CYP83B1 overexpression leads to loss of apical dominance typical of auxin deficit. CYP83B1 N-hydroxylates indole-3-acetaldoxime to the corresponding aci-nitro compound, 1-aci-nitro-2-indolyl-ethane, with a Km of 3 μM and a turnover number of 53 min-1. The aci-nitro compound formed reacts non-enzymatically with thiol compounds to produce an N-alkyl-thiohy-droximate adduct, the committed precursor of glucosinolates. Thus, indole-3-acetaldoxime is the metabolic branch point between the primary auxin indole-3-acetic acid and indole glucosinolate biosynthesis in Arabidopsis.

Original languageEnglish (US)
Pages (from-to)101-111
Number of pages11
JournalPlant Cell
Volume13
Issue number1
DOIs
StatePublished - Jan 1 2001
Externally publishedYes

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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