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Barley mildew and its elicitor chitosan promote closed stomata by stimulating guard‐cell S‐type anion channels
Author(s) -
Koers Sandra,
GuzelDeger Aysin,
Marten Irene,
Roelfsema M. Rob G.
Publication year - 2011
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2011.04719.x
Subject(s) - guard cell , powdery mildew , biology , mildew , hordeum vulgare , elicitor , biophysics , blumeria graminis , microbiology and biotechnology , botany , biochemistry , plant disease resistance , poaceae , gene
Summary 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.