Characterization of auxin conjugates in Arabidopsis. Low steady-state levels of indole-3-acetyl-aspartate, indole-3-acetyl-glutamate, and indole-3-acetyl-glucose
- PMID: 10859188
- PMCID: PMC59026
- DOI: 10.1104/pp.123.2.589
Characterization of auxin conjugates in Arabidopsis. Low steady-state levels of indole-3-acetyl-aspartate, indole-3-acetyl-glutamate, and indole-3-acetyl-glucose
Abstract
Amide-linked indole-3-acetic acid (IAA) conjugates constitute approximately 90% of the IAA pool in the dicot Arabidopsis, whereas ester-linked conjugates and free IAA account for approximately 10% and 1%, respectively when whole seedlings are measured. We show here that IAA-aspartate Asp, IAA-glutamate (Glu), and IAA-glucose (Glc) are present at low levels in Arabidopsis. Nine-day-old wild-type Arabidopsis seedlings yielded 17.4 +/- 4.6 ng g(-1) fresh weight IAA-Asp and 3.5 +/- 1.6 ng g(-1) fresh weight IAA-Glu, and IAA-Glc was present at 7 to 17 ng g(-1) fresh weight in 12-d-old wild-type seedlings. Total IAA content in 9-d-old Arabidopsis seedlings was 1, 200 +/- 178 ng g(-1) fresh weight, so these three IAA conjugates together made up only 3% of the conjugate pool throughout the whole plant. We detected less than wild-type levels of IAA-Asp and IAA-Glu (7.8 +/- 0.4 ng g(-1) fresh weight and 1.8 +/- 0.3 ng g(-1) fresh weight, respectively) in an Arabidopsis mutant that accumulates conjugated IAA. Our results are consistent with IAA-Asp, IAA-Glu, and IAA-Glc being either minor, transient, or specifically localized IAA metabolites under normal growth conditions and bring into question the physiological relevance of IAA-Asp accumulation in response to high concentrations of exogenous IAA.
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References
-
- Bandurski RS, Kowalczyk S, Leznicki A, Mekhedov S, Momonoki Y, Oguri S. Proceedings of the 25th Annual Meeting of the Plant Growth Regulation Society. Vol. 26. 1998. Metabolic targets for control of IAA levels in maize. Plant Growth Regulation Society, Quarterly Bulletin, pp 181–186.
-
- Barratt N, Dong W, Gage D, Magnus V, Town C. Metabolism of exogenous auxin by Arabidopsis thaliana: identification of the conjugate Na-(indol-3-ylacetyl)-glutamine and initiation of a mutant screen. Physiol Plant. 1999;105:207–217.
-
- Bartel B, Fink G. ILR1, an amidohydrolase that releases active indole-3-acetic acid from conjugates. Science. 1995;268:1745–1748. - PubMed
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