Symposium II: Reactive oxygen species: balancing signaling and stress

Abs # 20003: Hydrogen peroxide signalling in stomatal guard cells

Presenter:	Neill, Steven J, steven.neill@uwe.ac.uk
Authors	Neill, Steven J (A)   Desikan, Radhika  (A)   Hancock, John T (A)   Hooley, Richard  (B)
Affiliations:	(A): Centre for Research in Plant Science,University of the West of England, Bristol, UK (B): Department of Biology and Biochemistry, University of Bath, UK

At relatively high concentrations the Reactive Oxygen Species hydrogen peroxide (H₂O₂) impacts negatively on plant cells, inducing oxidative damage and cell death. However, at lower concentrations, it functions as an endogenous signalling molecule, mediating responses to various stresses and stimuli and hormones such as abscisic acid (ABA) and indole-acetic acid, activating protein kinases including mitogen-activated protein kinases (MAPKs) and modulating the expression of many genes. H₂O₂ has already been shown to mediate stomatal closure in response to ABA. Here, we describe recent data from our laboratory that link H₂O₂ generation to stomatal closure induced by darkness and indicate a requirement for MAPK activation by H₂O₂. We also describe genetic and physiological data obtained with yeast and Arabidopsis mutants that identify signalling proteins that are essential for guard cell closure in response to H₂O₂.