Regulation of Abscisic Acid-Induced Stomatal Closure and Anion Channels by Guard Cell AAPK Kinase

Abstract

Abscisic acid (ABA) stimulates stomatal closure and thus supports water conservation by plants during drought. Mass spectrometry–generated peptide sequence information was used to clone a Vicia faba complementary DNA, AAPK , encoding a guard cell–specific ABA-activated serine-threonine protein kinase (AAPK). Expression in transformed guard cells of AAPK altered by one amino acid (lysine 43 to alanine 43) renders stomata insensitive to ABA-induced closure by eliminating ABA activation of plasma membrane anion channels. This information should allow cell-specific, targeted biotechnological manipulation of crop water status.