Rapid auxin-mediated changes in the proteome of the epidermal cells in rye coleoptiles: implications for the initiation of growth

In axial organs of juvenile plants, the phytohormone auxin (indole-3-acetic acid, IAA) rapidly mediates cell wall loosening and hence promotes turgor-driven elongation. In this study, we used rye (Secale cereale) coleoptile sections to investigate possible effects of IAA on the proteome of the cells...

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Veröffentlicht in:Plant biology (Stuttgart, Germany) Germany), 2012-05, Vol.14 (3), p.420-427
Hauptverfasser: Deng, Z., Xu, S., Chalkley, R. J., Oses-Prieto, J. A., Burlingame, A. L., Wang, Z.-Y., Kutschera, U.
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Sprache:eng
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Zusammenfassung:In axial organs of juvenile plants, the phytohormone auxin (indole-3-acetic acid, IAA) rapidly mediates cell wall loosening and hence promotes turgor-driven elongation. In this study, we used rye (Secale cereale) coleoptile sections to investigate possible effects of IAA on the proteome of the cells. In a first set of experiments, we document that IAA causes organ elongation via promotion of expansion of the rigid outer wall of the outer epidermis. A quantitative comparison of the proteome (membrane-associated proteins), using two-dimensional difference gel electrophoresis (2-D DIGE), revealed that, within 2 h of auxin treatment, at least 16 protein spots were up- or down-regulated by IAA. These proteins were identified using reverse-phase liquid chromatography electrospray tandem mass spectrometry. Four of these proteins were detected in the growth-controlling outer epidermis and were further analysed. One epidermal polypeptide, a small Ras-related GTP-binding protein, was rapidly down-regulated by IAA (after 0.5 h of incubation) by -35% compared to the control. Concomitantly, a subunit of the 26S proteasome was up-regulated by IAA (+30% within 1 h). In addition, this protein displayed IAA-mediated post-translational modification. The implications of these rapid auxin effects with respect to signal transduction and IAA-mediated secretion of glycoproteins (osmiophilic nano-particles) into the growth-controlling outer epidermal wall are discussed.
ISSN:1435-8603
1438-8677
DOI:10.1111/j.1438-8677.2011.00513.x