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

Abstract

significant differences between axon-bearing and ax-presented (abstract 291.5) at the 29th Meeting of the 26. A. 8. Ali and A. M. Thomson,]. ~h~s i o l . (london) 507, on-lacking dendrites.Abscisic acid (ABA) stimulates stomatal closure and thus supports water conservation by plants during drought. Mass spectrometry-generated peptide sequence information was used t o 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 t o alanine 43) renders stomata insensitive t o 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.

Signalling drought in guard cells

“…As a result, ABI1 and ABI2 may negatively regulate the anion channels and/or K + channels. This is consistent with the positive regulation of anion channels by AAPK (Li et al 2000). However, because studies on AAPK and ABIs have been conducted in different plants and in a different genetic context, it is premature to conclude whether AAPK and ABIs serve as counteracting kinase and phosphatases in anion channel regulation by ABA.…”

“…Using a biochemical approach, two studies (Li & Assmann 1996;Mori & Muto 1997) identified an ABA-activated protein kinase (AAPK) from guard cells of Vicia faba. Cloning of this kinase and further genetic manipulation in guard cells indicates that AAPK is involved in the regulation of the slow anion channel by ABA (Li et al 2000). Because AAPK is not regulated by Ca 2+ , AAPK regulation of the anion channel is located in the Ca 2+ -independent branch of ABA signalling pathway.…”

Roles of ion channels and transporters in guard cell signal transduction

“…First came the cloning and characterization of a V. faba Ca 2+ -independent ABA-activated protein kinase (AAPK) [100][101][102], with an ortholog in Arabidopsis named OST1 [103]. Expression of a dominant negative form of AAPK resulted in insensitivity of ABA-induced closure of guard cells and impaired ABA-activation of S-type anion currents.…”

The mutual responses of higher plants to environment: Physiological and microbiological aspects

“…Plants live in soil-plant-atmosphere continuum (SPAC) environment, and they have to coordinate the mechanisms of diverse types to respond to the above changing environment at any time for sustainable survival [4][5][6][7][8][9][21][22][23][24][25][26][27][28][29][47][48][49][50][51][52][53][54][55][56][57][58][59]. Plant production realization is obtained eventually through physiological pathways at least at the level of individual and community [102][103][104][105][106][107][108][109]120,[130][131][132][133][134][135][136][137][138][139][140].…”