Decreased permeability as a mechanism of resistance to methyl benzimadazol-2-yl carbamate (MBC) in Sporobolomyces roseus.
Mutants of Sporobolomyces roseus resistant to benzimidazole fungicides varied in their responses to 2-(thiazol-4-yl) benzimidazole (thiabendazole, TBZ), methyl 1-(butylcarbamoyl)-benzimidazol-2-yl carbamate (benomyl) and methyl benzimidazol-2-yl carbamate (carbendazim, MCB). Incorporation of [14C] MBC into trichloroacetic acid extracts of the sensitive strain S4 increased during a 2 h incubation period, whereas incorporation into the resistant mutant M55 was unchanged. [14C] MBC uptake by S4 cells was five times higher than that by M55. MBC was identified as the main radioactive compound inside the S4 cells and reached a level of 2.4 mug/100 mg dry wt. The compound MBC enters the cells of Sp. roseus by a temperature-, energy-, pH- and concentration-dependent transport system which may be specific for compounds containing a benzimidazole nucleus. It is suggested that tolerance of M55 to MBC is due to decreased permeability of the cell to this compound.
D001542:Benomyl / Q000378:metabolism / Q000494:pharmacology; D001562:Benzimidazoles / Q000378:metabolism / Q000494:pharmacology*; D001693:Biological Transport, Active; D002219:Carbamates; D002463:Cell Membrane Permeability; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D005659:Fungicides, Industrial / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D003904:Mitosporic Fungi / Q000187:drug effects* / Q000378:metabolism; D009154:Mutation; D013696:Temperature; D013827:Thiabendazole / Q000378:metabolism / Q000494:pharmacology
D001562:Benzimidazoles; D002219:Carbamates; D005659:Fungicides, Industrial; D013827:Thiabendazole; D001542:Benomyl