This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: indole-3-acetic acid degradation II, IAA catabolism II, IAA turnover II, IAA oxidation II, IAA degradation II
|Superclasses:||Degradation/Utilization/Assimilation → Hormones Degradation → Plant Hormones Degradation → Auxins Degradation|
Some taxa known to possess this pathway include : Populus tremula x Populus tremuloides
Expected Taxonomic Range: Magnoliophyta
The plant hormone indole-3-acetic acid (IAA) can be degraded (inactivated) via either decarboxylative or non-decarboxylative oxidation. Decarboxylative oxidation involves plant peroxidase. The pathway and role of decarboxylative oxidation in IAA metabolism in higher plants are not clear. Studies in various plants on non-decarboxylative oxidation suggest it is the major catabolic route of IAA. Different plant species however employs different initial steps in non-decarboxylative oxidation. Maize readily oxidizes free IAA whereas hybrid aspen oxidizes aspartic acid-conjugated IAA (IAA-asp). Arabidopsis, on the other hand, oxidizes both free IAA and IAA-asp. These representative pathways are curated separately in the Metacyc database.
The degradation pathway in hybrid aspen as depicted here is based solely on in-vivo shoot feeding experiments [Tuominen94]. No enzyme or gene information is currently available. The end product in the pathway, 2-oxindole-3-acetic acid, may be subjected to further hydroxylation. The position of the hydroxyl group is not identified.
Variants: indole-3-acetate conjugate biosynthesis II, indole-3-acetate degradation I, indole-3-acetate degradation III, indole-3-acetate degradation IV, indole-3-acetate degradation V, indole-3-acetate degradation VI, indole-3-acetate degradation VII, indole-3-acetate degradation VIII (bacterial)
Kowalczyk: Kowalczyk, Mariusz "Metabolism and homeostasis of indole-3-acetic acid in Arabidopsis thaliana." Doctoral diss. Dept. of Forest Genetics and Plant Physiol., SLU. Acta Universitatis Agriculturae Sueciae. Silvestria Vol. 256.
Tuominen94: Tuominen H, Ostin A, Sandberg G, Sundberg B (1994). "A Novel Metabolic Pathway for Indole-3-Acetic Acid in Apical Shoots of Populus tremula (L.) x Populus tremuloides (Michx.)." Plant Physiol 106(4);1511-1520. PMID: 12232425
Staswick05: Staswick PE, Serban B, Rowe M, Tiryaki I, Maldonado MT, Maldonado MC, Suza W (2005). "Characterization of an Arabidopsis enzyme family that conjugates amino acids to indole-3-acetic acid." Plant Cell 17(2);616-27. PMID: 15659623
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