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Oral secretions from herbivorous lepidopteran larvae exhibit ion channel‐forming activities
Author(s) -
Maischak Heiko,
Grigoriev Pavel A.,
Vogel Heiko,
Boland Wilhelm,
Mithöfer Axel
Publication year - 2007
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.01.067
Subject(s) - spodoptera , depolarization , ion channel , membrane , biophysics , aequorin , chemistry , exigua , lipid bilayer , biochemistry , insect , ion , phospholipid , biology , botany , organic chemistry , recombinant dna , receptor , intracellular , gene
Feeding insects introduce oral secretions (OS) into the wounded tissue of the attacked plant. Various OS‐derived molecules must be involved in subsequent processes including the induction of plant defence reactions. Using the planar lipid bilayer membrane technique, isolated OS were analyzed with respect to their membrane activities. Transmembrane ion fluxes were generated by OS of eight different lepidopteran larvae, all of which form comparable ion channels in artificial membranes. Currents were characterized by long lasting open times and conductivities from 250 pS up to 1100 pS. Channels formed by Spodoptera exigua secretions showed a preference for cations over anions. OS also induced a transient increase of the cytosolic calcium concentration in soybean cells, determined by the aequorin technique. Known compounds of the OS, fatty‐acid–glutamine conjugates, also interfered with the membrane but were unable to form stable channels. Since ion fluxes and depolarization are early responses upon insect feeding, OS‐derived components may be involved in the elicitation process by direct interaction with the plant membranes.