Expression of a Cs(+)-resistant guard cell K+ channel confers Cs(+)-resistant, light-induced stomatal opening in transgenic arabidopsis.
- 1 October 1997
- journal article
- Published by Oxford University Press (OUP) in Plant Cell
- Vol. 9 (10) , 1843-1857
- https://doi.org/10.1105/tpc.9.10.1843
Abstract
Inward-rectifying K+ (K+in) channels in the guard cell plasma membrane have been suggested to function as a major pathway for K+ influx into guard cells during stomatal opening. When K+in channels were blocked with external Cs+ in wild-type Arabidopsis guard cells, light-induced stomatal opening was reduced. Transgenic Arabidopsis plants were generated that expressed a mutant of the guard cell K+in channel, KAT1, which shows enhanced resistance to the Cs+ block. Stomata in these transgenic lines opened in the presence of external Cs+. Patch-clamp experiments with transgenic guard cells showed that inward K+(in) currents were blocked less by Cs+ than were K+ currents in controls. These data provide direct evidence that KAT1 functions as a plasma membrane K+ channel in vivo and that K+in channels constitute an important mechanism for light-induced stomatal opening. In addition, biophysical properties of K+in channels in guard cells indicate that components in addition to KAT1 may contribute to the formation of K+in channels in vivoKeywords
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