An anion channel in Arabidopsis hypocotyls activated by blue light.
A rapid, transient depolarization of the plasma membrane in seedling stems is one of the earliest effects of blue light detected in plants. It appears to play a role in transducing blue light into inhibition of hypocotyl (stem) elongation, and perhaps other responses. The possibility that activation of a Cl- conductance is part of the depolarization mechanism was raised previously and addressed here. By patch clamping hypocotyl cells isolated from dark-grown (etiolated) Arabidopsis seedlings, blue light was found to activate an anion channel residing at the plasma membrane. An anion-channel blocker commonly known as NPPB 15-nitro-2-(3-phenylpropylamino)-benzoic acid] potently and reversibly blocked this anion channel. NPPB also blocked the blue-light-induced depolarization in vivo and decreased the inhibitory effect of blue light on hypocotyl elongation. These results indicate that activation of this anion channel plays a role in transducing blue light into growth inhibition.
Cho
M H
MH
Department of Botany, University of Wisconsin, Madison 53706.
Spalding
E P
EP
D000838:Anions; D017360:Arabidopsis / Q000502:physiology* / Q000528:radiation effects; D018548:Cotyledon / Q000502:physiology / Q000528:radiation effects; D003624:Darkness; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects / Q000528:radiation effects; D009579:Nitrobenzoates / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011523:Protoplasts / Q000502:physiology
D000838:Anions; D007473:Ion Channels; D009579:Nitrobenzoates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid