@article{mbs:/content/journal/micro/10.1099/00221287-135-8-2209, author = "Larossa, Robert A. and Van Dyk, Tina K.", title = "Leaky Pantothenate and Thiamin Mutations of Salmonella typhimurium Conferring Sulphometuron Methyl Sensitivity", journal= "Microbiology", year = "1989", volume = "135", number = "8", pages = "2209-2222", doi = "https://doi.org/10.1099/00221287-135-8-2209", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-135-8-2209", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "The herbicide suphometuron methyl inhibits the utilization of pyruvate and 2-ketobutyrate by the branched-chain amino acid biosynthetic enzyme acetolactate synthase. Eighteen insertions of the transposon Tn10 into the genome of Salmonella typhimurium LT2 caused hypersensitivity to this herbicide. Five of these insertions conferred a partial auxotrophic requirement. Concurrent herbicide sensitivity and heat-labile pantothenate auxotrophy was due to panD::Tn10 mutations, while coincident sulphometuron methyl sensitivity and thiamin auxotrophy was attributable to thiA::Tn10 mutations. The phenotypes of these mutations suggested that coenzyme A and thiamin pyrophosphate availability modulated the cells’ response to sulphometuron methyl. A model suggesting a key role for 2-ketobutyrate accumulation in herbicide action is supported by the function of thiamin pyrophosphate in 2-ketoacid metabolism and the known role of a 2-ketoacid in coenzyme A synthesis.", }