Open AccessReceptor-mediated activation of a plant Ca 2+ -permeable ion channel involved in pathogen defense
Author(s) -
Sabine Zimmermann,
Thorsten Nürnberger,
JeanMarie Frachisse,
Wolfgang Wirtz,
J. Guern,
Rainer Hedrich,
Dierk Scheel
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.6.2751
Subject(s) - elicitor , ion channel , biophysics , apoplast , microbiology and biotechnology , extracellular , biology , receptor , biochemistry , chemistry , cell wall , gene
Pathogen recognition at the plant cell surface typically results in the initiation of a multicomponent defense response. Transient influx of Ca2+ across the plasma membrane is postulated to be part of the signaling chain leading to pathogen resistance. Patch-clamp analysis of parsley protoplasts revealed a novel Ca2+ -permeable, La3+ -sensitive plasma membrane ion channel of large conductance (309 pS in 240 mM CaCl2 ). At an extracellular Ca2+ concentration of 1 mM, which is representative of the plant cell apoplast, unitary channel conductance was determined to be 80 pS. This ion channel (LEAC, forl arge conductancee licitor-a ctivated ionc hannel) is reversibly activated upon treatment of parsley protoplasts with an oligopeptide elicitor derived from a cell wall protein ofPhytophthora sojae . Structural features of the elicitor found previously to be essential for receptor binding, induction of defense-related gene expression, and phytoalexin formation are identical to those required for activation of LEAC. Thus, receptor-mediated stimulation of this channel appears to be causally involved in the signaling cascade triggering pathogen defense in parsley.