Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2000 Jun;123(2):589-96.
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

Affiliations

Characterization of auxin conjugates in Arabidopsis. Low steady-state levels of indole-3-acetyl-aspartate, indole-3-acetyl-glutamate, and indole-3-acetyl-glucose

Y Y Tam et al. Plant Physiol. 2000 Jun.

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.

PubMed Disclaimer

Figures

Figure 1
Figure 1
The 70-eV electron impact full scan mass spectrum from m/z 50 to 510 of methyl [13C6]IAA-Asp (internal standard) and methyl IAA-Asp isolated from Arabidopsis.
Figure 2
Figure 2
The 70-eV electron impact full scan mass spectrum from m/z 50 to 550 of methyl [13C6]IAA-Glu (internal standard) and methyl IAA-Glu isolated from Arabidopsis.
Figure 3
Figure 3
The 70-eV electron impact full scan mass spectrum from m/z 50 to 510 of acetyl IAA-Glc isolated from Arabidopsis (no internal standard added).

Similar articles

Cited by

References

    1. 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.
    1. 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.
    1. Bartel B, Fink G. ILR1, an amidohydrolase that releases active indole-3-acetic acid from conjugates. Science. 1995;268:1745–1748. - PubMed
    1. Bialek K, Cohen JD. Isolation and partial characterization of the major amide-linked conjugate of indole-3-acetic acid from Phaseolus vulgaris L. Plant Physiol. 1986;80:99–104. - PMC - PubMed
    1. Boerjan W, Cervera M, Delarue M, Beeckman T, Dewitte W, Bellini C, Caboche M, Van Onckelen H, Van Montagu M, Inzé D. superroot, a recessive mutation in Arabidopsis, confers auxin overproduction. Plant Cell. 1995;7:1405–1419. - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources