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Planta

, Volume 222, Issue 3, pp 530–534 | Cite as

Stems of the Arabidopsis pin1-1 mutant are not deficient in free indole-3-acetic acid

  • Sarah E. Jones
  • J. Seph DeMeo
  • Noel W. Davies
  • Sophie E. Noonan
  • John J. Ross
Original Article

Abstract

The pin1-1 mutant of Arabidopsis thaliana has been pivotal for studies on auxin transport and on the role of auxin in plant development. It was reported previously that when whole shoots were analysed, levels of the major auxin, indole-3-acetic acid (IAA) were dramatically reduced in the mutant, compared with the WT (Okada et al. 1991). The cloning of PIN1, however, provided evidence that this gene encodes a facilitator of auxin efflux, raising the question of how the pin1-1 mutation might reduce overall IAA levels as well as IAA transport. We therefore re-examined IAA levels in individual parts of pin1-1 and WT plants, focusing on inflorescence stems. Our data show that there is in fact no systemic IAA deficiency in the mutant. The previously reported difference between mutant and WT may have been due to the inclusion of reproductive structures in the WT harvest: we show here that the inflorescence itself contains high levels of IAA. We reconcile the normal IAA levels of pin1-1 inflorescence stems with their (previously-reported) reduced ability to transport IAA by presenting evidence that the auxin in mutant stems is not imported from their apical portion. Our data also indicate that levels of another auxin, indole-3-butyric acid (IBA), are very low in stems of the genotypes used in this study.

Keywords

Arabidopsis Auxin content Auxin transport GC-MS-MS  pin1-1 mutant 

Abbreviations

GC-MS-MS

Gas chromatography/mass spectrometry/mass spectrometry

IAA

Indole-3-acetic acid

IBA

Indole-3-butyric acid

WT

Wild type

Notes

Acknowledgements

We thank Ian Cummings and Tracey Winterbottom for technical assistance, Jennifer Smith for assistance with the figures, Gregory Symons and James Reid for comments on the manuscript, and David Smyth (Monash University, Victoria, Australia) for the gift of the pin1-1 mutant.

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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Sarah E. Jones
    • 1
  • J. Seph DeMeo
    • 1
  • Noel W. Davies
    • 1
  • Sophie E. Noonan
    • 1
  • John J. Ross
    • 1
  1. 1.School of Plant ScienceUniversity of TasmaniaHobartAustralia

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