Metabolic regulation of the plant hormone indole-3-acetic acid
The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and that over-express each member in the family in terms of the level and route of IAA biosynthesis. Together, these allowed further development of a comprehensive picture of the pathways and regulatory components that are involved in IAA homeostasis in higher plants.
- Research Organization:
- Univ. of Minnesota, Minneapolis, MN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- FG02-00ER15079
- OSTI ID:
- 966706
- Report Number(s):
- DOE/ER/15079-3; 1719-413-6143; TRN: US201003%%729
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ARABIDOPSIS
BIOSYNTHESIS
DECARBOXYLASES
DILUTION
ENDOSPERM
ENZYMES
GENES
HOMEOSTASIS
HORMONES
IN VITRO
MAIZE
METABOLITES
MUTANTS
PLANT GROWTH
PRODUCTION
PROTEINS
REGULATIONS
SEEDLINGS
STABLE ISOTOPES
TRYPTOPHAN
Plant Growth
Plant hormones
Auxin biosynthesis
Plant metabolism
Indole