Choline- and acetylcholine-induced changes in the morphology of Fusarium graminearum: evidence for the involvement of the choline transport system and acetylcholinesterase

• Published in: Microbiology (Society for General Microbiology) 1995-06, Vol.141 (6), p.1309-1314
• Main Authors: Robson, Geoffrey D, Wiebe, Marilyn G, Cunliffe, Bryan, Trinci, Anthony P. J
• Format: Article
• Language: English
• Subjects: Acetylcholine - metabolism; Acetylcholine - pharmacology; Acetylcholinesterase - metabolism; Acetylglucosamine - metabolism; Betaine - metabolism; Betaine - pharmacology; Biological and medical sciences; Biological Transport; Cell Wall - metabolism; Chitin Synthase - metabolism; Choline - metabolism; Choline - pharmacology; Cholinesterase Inhibitors - pharmacology; Drug Resistance, Microbial - genetics; Ethanolamine; Ethanolamines - metabolism; Ethanolamines - pharmacology; Fundamental and applied biological sciences. Psychology; Fungal Proteins - metabolism; Fusarium - drug effects; Fusarium - genetics; Fusarium - metabolism; Fusarium - ultrastructure; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; Hemicholinium 3 - pharmacology; Mechlorethamine - pharmacology; Membrane Proteins - metabolism; Microbiology; Mutagenesis; Mycology; Quaternary Ammonium Compounds - pharmacology
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/13500872-141-6-1309

*Microbiology Research Group, 1.800 Stopford Building, School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK 1 Tel: + 44 161 275 5048. Fax: [phone]. ABSTRACT The response of Fusarium graminearum to choline, acetylcholine and a number of related analogues was investigated and their ability to induce a morphological response quantified. A number of mutants resistant to the alkylating agent nitrogen mustard (nim strains) were generated and found to have lost the ability to transport choline. These mutants were found to be insensitive to choline and acetylcholine but not to betaine, ethanolamine and other analogues. In addition, the non-competitive inhibitor hemicholinium-3 was also found to reduce the morphological effect of choline, proving that transport of choline into the hypha is essential for the morphological response. Acetylcholinesterase inhibitors blocked the morphological response to acetylcholine but had no effect on the response to choline, suggesting the presence of a membrane- or wall-bound acetylcholinesterase that hydrolyses acetylcholine to choline which subsequently induces the morphological response. Studies on the in vivo chitin synthase activity revealed that addition of choline caused a transient 75% increase in chitin synthase activity within 30 s, the rate rapidly returning to that observed before the addition of choline. No such effect was observed with the nim mutants. Keywords: F usarium graminearum , choline, hyphal growth, nitrogen mustard, chitin synthase