Research Notes: Bacterial Blotch Disease of the Cultivated Mushroom Is Caused by an Ion Channel Forming Lipodepsipeptide Toxin. Catherine L. Brodey. Botany School, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom. Paul B. Rainey, Mark Tester, and Keith Johnstone. Botany School, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom.. MPMI 4:407-411. Accepted 8 February 1991. This article is in the public domain and not copryightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1991.

Tolaasin, a lipodepsipeptide toxin produced by the mushroom pathogen Pseudomonas tolaasii was shown to form voltage-dependent, cation-selective, ion channels in planar lipid bilayers. Tolaasin-induced ion channels were inhibited by the addition of Zn²⁺, which also inhibited the activity of tolaasin on horse erythrocytes and mushroom tissue. Tolaasin-144, an altered form of tolaasin lacking three consecutive D-amino acids from the alpha-helical portion of the molecule, did not form ion channels in planar lipid bilayers, did not lyse erythrocytes, and showed reduced ability to cause disease symptoms on mushroom tissue.