RT Journal Article SR Electronic(1) A1 TAN, H. A1 COOKE, F.YR 1978 T1 Mutants with Increased Sensitivity to Canavanine in the Fungus Coniochaeta velutina JF Microbiology, VO 108 IS 2 SP 247 OP 259 DO https://doi.org/10.1099/00221287-108-2-247 PB Microbiology Society, SN 1465-2080, AB Mutants of Coniochaeta velutina with increased sensitivity to canavanine were derived from wild-type, pyr-3 (presumably defective in carbamoyl-phosphate synthase for pyrimidine synthesis), arg (blocked in steps prior to arginine formation) and pro (blocked in steps prior to glutamate semialdehyde formation) strains, and were classified into eight distinct groups by genetic mapping. Four canavanine-sensitive genes (cns) were allelic or very tightly linked to known arg loci. The pairs of genes involved were cns A and arg-3 (arginine requirer), cnsB and arg-7 (citrulline requirer), cnsC and arg-2 (citrulline requirer) and cnsG and arg-1 (ornithine requirer). Another (cnsF) was mapped in linkage group III. A relationship was shown between the level of intracellular arginine and the extent of canavanine sensitivity; cns strains contain less intracellular arginine than the less sensitive wild-type. In most cases, this was shown to result from mutations affecting the enzyme(s) involved in arginine metabolism. cnsA and cnsG were thought to be affected in arginine- and ornithine-synthesizing enzymes, respectively. cnsB and cnsC exhibited a requirement for citrulline when the two genes were combined and were suggested to be loci specifying the two polypeptide chains of carbamoyl-phosphate synthase for arginine synthesis. cnsH was the locus controlling ornithine carbamoyltransferase. The metabolic lesions of the other cns mutants (cnsD, cnsE and cnsF) were unclear. Of the eight cns mutants, six could suppress pyr-3M and/or pro mutations: cnsG was able to suppress pyr-3M; cnsB, cnsE, cnsD and cnsF were effective in suppressing pro; cnsH suppressed both pyr and pro. The mechanism of the pyr and pro suppressions was explained on the basis of metabolic cross-feeding., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-108-2-247