Choline- and acetylcholine-induced changes in the morphology of Fusarium graminearum: evidence for the involvement of the choline transport system and acetylcholinesterase.
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.
Robson
Geoffrey D
GD
*Microbiology Research Group, 1.800 Stopford Building, School of Biological Sciences, University of Manchester, Manchester, M13 9PT, UK.
Wiebe
Marilyn G
MG
*Microbiology Research Group, 1.800 Stopford Building, School of Biological Sciences, University of Manchester, Manchester, M13 9PT, UK.
Cunliffe
Bryan
B
*Microbiology Research Group, 1.800 Stopford Building, School of Biological Sciences, University of Manchester, Manchester, M13 9PT, UK.
Trinci
Anthony P J
APJ
*Microbiology Research Group, 1.800 Stopford Building, School of Biological Sciences, University of Manchester, Manchester, M13 9PT, UK.
D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology*; D000110:Acetylcholinesterase / Q000378:metabolism*; D000117:Acetylglucosamine / Q000378:metabolism; D001622:Betaine / Q000378:metabolism / Q000494:pharmacology; D001692:Biological Transport; D002473:Cell Wall / Q000378:metabolism; D002687:Chitin Synthase / Q000378:metabolism; D002794:Choline / Q000378:metabolism / Q000494:pharmacology*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004352:Drug Resistance, Microbial / Q000235:genetics; D019856:Ethanolamine; D004983:Ethanolamines / Q000378:metabolism / Q000494:pharmacology; D005656:Fungal Proteins / Q000378:metabolism*; D005670:Fusarium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D006426:Hemicholinium 3 / Q000494:pharmacology; D008466:Mechlorethamine / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism; D016296:Mutagenesis; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology
D002800:Cholinesterase Inhibitors; D004983:Ethanolamines; D005656:Fungal Proteins; D008565:Membrane Proteins; D000644:Quaternary Ammonium Compounds; D006426:Hemicholinium 3; D001622:Betaine; D008466:Mechlorethamine; D019856:Ethanolamine; D002687:Chitin Synthase; D000110:Acetylcholinesterase; D002794:Choline; D000109:Acetylcholine; D000117:Acetylglucosamine