1. Barley mildew and its elicitor chitosan promote closed stomata by stimulating guard-cell S-type anion channels.
- Author
-
Koers S, Guzel-Deger A, Marten I, and Roelfsema MR
- Subjects
- Hordeum metabolism, Host-Pathogen Interactions, Hyphae physiology, Ion Channels metabolism, Membrane Potentials, Plant Diseases microbiology, Plant Stomata metabolism, Potassium metabolism, Ascomycota physiology, Chitosan metabolism, Hordeum microbiology, Ion Channel Gating, Plant Stomata microbiology
- Abstract
Stomatal closure is known to be associated with early defence responses of plant cells triggered by microbe-associated molecular patterns (MAMPs). However, the molecular mechanisms underlying these guard-cell responses have not yet been elucidated. We therefore studied pathogen-induced changes in ion channel activity in Hordeum vulgare guard cells. Barley mildew (Blumeria graminis) hyphae growing on leaves inhibited light-induced stomatal opening, starting at 9 h after inoculation, when appressoria had developed. Alternatively, stomatal closure was induced by nano-infusion of chitosan via open stomata into the sub-stomatal cavity. Experiments using intracellular double-barreled micro-electrodes revealed that mildew stimulated S-type (slow) anion channels in guard cells. These channels enable the efflux of anions from guard cells and also promote K(+) extrusion by altering the plasma membrane potential. Stimulation of S-type anion channels was also provoked by nano-infusion of chitosan. These data suggest that MAMPs of mildew hyphae penetrating the cuticle provoke activation of S-type anion channels in guard cells. In response, guard cells extrude K(+) salts, resulting in stomatal closure. Plasma membrane anion channels probably represent general targets of MAMP signaling in plants, as these elicitors depolarize the plasma membrane of various cell types., (© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.)
- Published
- 2011
- Full Text
- View/download PDF