Combined action of guard cell plasma membrane rapid- and slow-type anion channels in stomatal regulation. Issue 4 (2nd May 2021)

• Record Type: Journal Article
• Authors: Jalakas, Pirko; Nuhkat, Maris; Vahisalu, Triin; Merilo, Ebe; Brosché, Mikael; Kollist, Hannes
• Is Part Of: Plant physiology. Volume 187:Issue 4(2021)
• Page Start: 2126
• Page End: 2133
• Publication Date: 2021-05-02
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1093/plphys/kiab202
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract: Initiation of stomatal closure by various stimuli requires activation of guard cell plasma membrane anion channels, which are defined as rapid (R)- and slow (S)-type. The single-gene loss-of-function mutants of these proteins are well characterized. However, the impact of suppressing both the S- and R-type channels has not been studied. Here, by generating and studying double and triple Arabidopsis thaliana mutants of SLOW ANION CHANNEL1 (SLAC1), SLAC1 HOMOLOG3 (SLAH3), and ALUMINUM-ACTIVATED MALATE TRANSPORTER 12/QUICK-ACTIVATING ANION CHANNEL 1 (QUAC1), we show that impairment of R- and S-type channels gradually increased whole-plant steady-state stomatal conductance. Ozone-induced cell death also increased gradually in higher-order mutants with the highest levels observed in the quac1 slac1 slah3 triple mutant . Strikingly, while single mutants retained stomatal responsiveness to abscisic acid, darkness, reduced air humidity, and elevated CO2, the double mutant lacking SLAC1 and QUAC1 was nearly insensitive to these stimuli, indicating the need for coordinated activation of both R- and S-type anion channels in stomatal closure. Abstract : Combined impairment of guard cell slow and rapid anion channels results in increased stomatal conductance and complete stomatal insensitivity to abscisic acid, darkness, and elevated CO2 .