Plant physiology (Bethesda), 2004-06, Vol.135 (2), p.978-988
2004
Details
- Autor(en) / Beteiligte
- Titel
- family of auxin-conjugate hydrolases that contributes to free indole-3-acetic acid levels during Arabidopsis germination
- Ist Teil von
- Plant physiology (Bethesda), 2004-06, Vol.135 (2), p.978-988
- Ort / Verlag
- United States: American Society of Plant Biologists
- Erscheinungsjahr
- 2004
- Link zum Volltext
- Quelle
- Elektronische Zeitschriftenbibliothek - Freely accessible e-journals
- Beschreibungen/Notizen
- Auxins are hormones important for numerous processes throughout plant growth and development. Plants use several mechanisms to regulate levels of the auxin indole-3-acetic acid (IAA), including the formation and hydrolysis of amide-linked conjugates that act as storage or inactivation forms of the hormone. Certain members of an Arabidopsis amidohydrolase family hydrolyze these conjugates to free IAA in vitro. We examined amidohydrolase gene expression using northern and promoter-beta-glucuronidase analyses and found overlapping but distinct patterns of expression. To examine the in vivo importance of auxin-conjugate hydrolysis, we generated a triple hydrolase mutant, ilr1 iar3 ill2, which is deficient in three of these hydrolases. We compared root and hypocotyl growth of the single, double, and triple hydrolase mutants on IAA-Ala, IAA-Leu, and IAA-Phe. The hydrolase mutant phenotypic profiles on different conjugates reveal the in vivo activities and relative importance of ILR1, IAR3, and ILL2 in IAA-conjugate hydrolysis. In addition to defective responses to exogenous conjugates, ilr1 iar3 ill2 roots are slightly less responsive to exogenous IAA. The triple mutant also has a shorter hypocotyl and fewer lateral roots than wild type on unsupplemented medium. As suggested by the mutant phenotypes, ilr1 iar3 ill2 imbibed seeds and seedlings have lower IAA levels than wild type and accumulate IAA-Ala and IAA-Leu, conjugates that are substrates of the absent hydrolases. These results indicate that amidohydrolases contribute free IAA to the auxin pool during germination in Arabidopsis.
- Sprache
- Englisch
- Identifikatoren
- ISSN: 0032-0889eISSN: 1532-2548DOI: 10.1104/pp.104.039677Titel-ID: cdi_proquest_miscellaneous_66658237
- Format
- –
- Schlagworte
- alanine, amide hydrolases, amidohydrolases, Amidohydrolases - genetics, Amidohydrolases - metabolism, Amino acids, Arabidopsis - enzymology, Arabidopsis - growth & development, Arabidopsis Proteins - genetics, Arabidopsis Proteins - metabolism, Arabidopsis thaliana, aspartic acid, Auxin, Auxins, Blotting, Northern, Development and Hormone Action, Enzymes, Gene expression, gene expression regulation, Gene Expression Regulation, Enzymologic - drug effects, Gene Expression Regulation, Plant - drug effects, Genetic aspects, Germination, Germination - physiology, Glucuronidase - genetics, Glucuronidase - metabolism, hydrolases, Hydrolysis, Hypocotyls, indole acetic acid, Indoleacetic Acids - metabolism, Indoleacetic Acids - pharmacology, Insulin antibodies, leucine, molecular sequence data, Mutation, nucleotide sequences, Oligonucleotides, Phenotype, phenotypic variation, phenylalanine, Plant Growth Regulators - pharmacology, plant morphology, Plant mutation, plant proteins, Plant roots, Plants, seed development, seed germination, Seedlings, transgenic plants