title: TAA1-mediated auxin biosynthesis is essential for hormone crosstalk and plant development.
abstract: Plants have evolved a tremendous ability to respond to environmental changes by adapting their growth and development. The interaction between hormonal and developmental signals is a critical mechanism in the generation of this enormous plasticity. A good example is the response to the hormone ethylene that depends on tissue type, developmental stage, and environmental conditions. By characterizing the Arabidopsis wei8 mutant, we have found that a small family of genes mediates tissue-specific responses to ethylene. Biochemical studies revealed that WEI8 encodes a long-anticipated tryptophan aminotransferase, TAA1, in the essential, yet genetically uncharacterized, indole-3-pyruvic acid (IPA) branch of the auxin biosynthetic pathway. Analysis of TAA1 and its paralogues revealed a link between local auxin production, tissue-specific ethylene effects, and organ development. Thus, the IPA route of auxin production is key to generating robust auxin gradients in response to environmental and developmental cues.
authors.affiliation: Department of Genetics, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Anna N
authors.initials: AN
authors.lastname: Stepanova
authors.forename: Joyce
authors.initials: J
authors.lastname: Robertson-Hoyt
authors.forename: Jeonga
authors.initials: J
authors.lastname: Yun
authors.forename: Larissa M
authors.initials: LM
authors.lastname: Benavente
authors.forename: De-Yu
authors.initials: DY
authors.lastname: Xie
authors.forename: Karel
authors.initials: K
authors.lastname: Dolezal
authors.forename: Alexandra
authors.initials: A
authors.lastname: Schlereth
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Jose M
authors.initials: JM
authors.lastname: Alonso
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D053898:Biosynthetic Pathways; D005030:Ethylenes / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000378:metabolism*; D007211:Indoles / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D018517:Plant Roots / Q000187:drug effects; D036226:Seedlings / Q000378:metabolism; D016415:Sequence Alignment; D051279:Tryptophan Transaminase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D005030:Ethylenes; D007210:Indoleacetic Acids; D007211:Indoles; C008122:indol-3-yl pyruvic acid; C036216:ethylene; D051279:Tryptophan Transaminase