TU Darmstadt / ULB / TUbiblio

Auxin-induced K+ channel expression represents an essential step in coleoptile growth and gravitropism.

Philippar, K. and Fuchs, I. and Luthen, H. and Hoth, S. and Bauer, C . S. and Haga, K. and Thiel, Gerhard and Ljung, K. and Sandberg, G. and Bottger, M. and Becker, D. and Hedrich, R. (1999):
Auxin-induced K+ channel expression represents an essential step in coleoptile growth and gravitropism.
In: Proceedings of the National Academy of Sciences of the United States of America, pp. 12186-91, 96, (21), ISSN 0027-8424,
[Article]

Abstract

Auxin-induced growth of coleoptiles depends on the presence of potassium and is suppressed by K+ channel blockers. To evaluate the role of K+ channels in auxin-mediated growth, we isolated and functionally expressed ZMK1 and ZMK2 (Zea mays K+ channel 1 and 2), two potassium channels from maize coleoptiles. In growth experiments, the time course of auxin-induced expression of ZMK1 coincided with the kinetics of coleoptile elongation. Upon gravistimulation of maize seedlings, ZMK1 expression followed the gravitropic-induced auxin redistribution. K+ channel expression increased even before a bending of the coleoptile was observed. The transcript level of ZMK2, expressed in vascular tissue, was not affected by auxin. In patch-clamp studies on coleoptile protoplasts, auxin increased K+ channel density while leaving channel properties unaffected. Thus, we conclude that coleoptile growth depends on the transcriptional up-regulation of ZMK1, an inwardly rectifying K+ channel expressed in the nonvascular tissue of this organ.

Item Type: Article
Erschienen: 1999
Creators: Philippar, K. and Fuchs, I. and Luthen, H. and Hoth, S. and Bauer, C . S. and Haga, K. and Thiel, Gerhard and Ljung, K. and Sandberg, G. and Bottger, M. and Becker, D. and Hedrich, R.
Title: Auxin-induced K+ channel expression represents an essential step in coleoptile growth and gravitropism.
Language: English
Abstract:

Auxin-induced growth of coleoptiles depends on the presence of potassium and is suppressed by K+ channel blockers. To evaluate the role of K+ channels in auxin-mediated growth, we isolated and functionally expressed ZMK1 and ZMK2 (Zea mays K+ channel 1 and 2), two potassium channels from maize coleoptiles. In growth experiments, the time course of auxin-induced expression of ZMK1 coincided with the kinetics of coleoptile elongation. Upon gravistimulation of maize seedlings, ZMK1 expression followed the gravitropic-induced auxin redistribution. K+ channel expression increased even before a bending of the coleoptile was observed. The transcript level of ZMK2, expressed in vascular tissue, was not affected by auxin. In patch-clamp studies on coleoptile protoplasts, auxin increased K+ channel density while leaving channel properties unaffected. Thus, we conclude that coleoptile growth depends on the transcriptional up-regulation of ZMK1, an inwardly rectifying K+ channel expressed in the nonvascular tissue of this organ.

Journal or Publication Title: Proceedings of the National Academy of Sciences of the United States of America
Volume: 96
Number: 21
Divisions: 10 Department of Biology > Plant Membrane Biophysics
?? fb10_botanik ??
10 Department of Biology
Date Deposited: 22 Jun 2011 07:43
Export:
Suche nach Titel in: TUfind oder in Google

Optionen (nur für Redakteure)

View Item View Item