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Title: 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 andmore » 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.« less
Authors:
Publication Date:
OSTI Identifier:
966706
Report Number(s):
DOE/ER/15079-3
1719-413-6143; TRN: US201003%%729
DOE Contract Number:
FG02-00ER15079
Resource Type:
Technical Report
Research Org:
University of Minnesota
Sponsoring Org:
USDOE Office of Energy Research (ER)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 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