Dominant negative guard cell K+ channel mutants reduce inward-rectifying K+ currents and light-induced stomatal opening in arabidopsis

J. M. Kwak, Y. Murata, V. M. Baizabal-Aguirre, J. Merrill, M. Wang, A. Kemper, S. D. Hawke, G. Tallman, J. I. Schroeder

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138 Citations (Scopus)

Abstract

Inward-rectifying potassium (K+in) channels in guard cells have been suggested to provide a pathway for K+ uptake into guard cells during stomatal opening. To test the proposed role of guard cell K+in channels in light-induced stomatal opening, transgenic Arabidopsis plants were generated that expressed dominant negative point mutations in the K+in channel subunit KAT1. Patch-clamp analyses with transgenic guard cells from independent lines showed that K+in current magnitudes were reduced by approximately 75% compared with vector-transformed controls at -180 mV, which resulted in reduction in light-induced stomatal opening by 38% to 45% compared with vector-transformed controls. Analyses of intracellular K+ content using both sodium hexanitrocobaltate (III) and elemental x-ray microanalyses showed that light-induced K+ uptake was also significantly reduced in guard cells of K+in channel depressor lines. These findings support the model that K+in channels contribute to K+ uptake during light-induced stomatal opening. Furthermore, transpirational water loss from leaves was reduced in the K+in channel depressor lines. Comparisons of guard cell K+in current magnitudes among four different transgenic lines with different K+in current magnitudes show the range of activities of K+in channels required for guard cell K+ uptake during light-induced stomatal opening.

Original languageEnglish
Pages (from-to)473-485
Number of pages13
JournalPlant physiology
Volume127
Issue number2
DOIs
Publication statusPublished - Jan 1 2001
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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    Kwak, J. M., Murata, Y., Baizabal-Aguirre, V. M., Merrill, J., Wang, M., Kemper, A., Hawke, S. D., Tallman, G., & Schroeder, J. I. (2001). Dominant negative guard cell K+ channel mutants reduce inward-rectifying K+ currents and light-induced stomatal opening in arabidopsis. Plant physiology, 127(2), 473-485. https://doi.org/10.1104/pp.010428