Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells

Autor: Benjamin Brandt, Shintaro Munemasa, Cun Wang, Desiree Nguyen, Taiming Yong, Paul G Yang, Elly Poretsky, Thomas F Belknap, Rainer Waadt, Fernando Alemán, Julian I Schroeder
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: eLife, Vol 4 (2015)
Druh dokumentu: article
ISSN: 2050-084X
DOI: 10.7554/eLife.03599
Popis: A central question is how specificity in cellular responses to the eukaryotic second messenger Ca2+ is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca2+-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca2+-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca2+-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruple mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca2+-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca2+-dependent and Ca2+-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca2+-signaling on a cellular, genetic, and biochemical level.
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