RRC ID 52863
著者 Eisenach C, Baetz U, Huck NV, Zhang J, De Angeli A, Beckers GJM, Martinoia E.
タイトル ABA-Induced Stomatal Closure Involves ALMT4, a Phosphorylation-Dependent Vacuolar Anion Channel of Arabidopsis.
ジャーナル Plant Cell
Abstract Stomatal pores are formed between a pair of guard cells and allow plant uptake of CO2 and water evaporation. Their aperture depends on changes in osmolyte concentration of guard cell vacuoles, specifically of K+ and Mal2- Efflux of Mal2- from the vacuole is required for stomatal closure; however, it is not clear how the anion is released. Here, we report the identification of ALMT4 (ALUMINUM ACTIVATED MALATE TRANSPORTER4) as an Arabidopsis thaliana ion channel that can mediate Mal2- release from the vacuole and is required for stomatal closure in response to abscisic acid (ABA). Knockout mutants showed impaired stomatal closure in response to the drought stress hormone ABA and increased whole-plant wilting in response to drought and ABA. Electrophysiological data show that ALMT4 can mediate Mal2- efflux and that the channel activity is dependent on a phosphorylatable C-terminal serine. Dephosphomimetic mutants of ALMT4 S382 showed increased channel activity and Mal2- efflux. Reconstituting the active channel in almt4 mutants impaired growth and stomatal opening. Phosphomimetic mutants were electrically inactive and phenocopied the almt4 mutants. Surprisingly, S382 can be phosphorylated by mitogen-activated protein kinases in vitro. In brief, ALMT4 likely mediates Mal2- efflux during ABA-induced stomatal closure and its activity depends on phosphorylation.
巻・号 29(10)
ページ 2552-2569
公開日 2017-10-1
DOI 10.1105/tpc.17.00452
PII tpc.17.00452
PMID 28874508
PMC PMC5774580
MeSH Abscisic Acid / pharmacology* Arabidopsis / drug effects Arabidopsis / metabolism Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism Droughts Phosphorylation / drug effects Plant Stomata / drug effects* Plant Stomata / metabolism* Signal Transduction / drug effects Vacuoles / drug effects Vacuoles / metabolism*
IF 9.618
引用数 24
リソース情報
シロイヌナズナ / 植物培養細胞・遺伝子 pst15045