Showing papers by "Adrian C. Newton published in 1988"
TL;DR: The phenotypes and genetic basis of these chlorate-resistant mutants resemble those in Aspergillus nidulans and Neurospora crassa, suggesting that nitrate assimilation in S. nodorum is similar to the well-characterized process in these other fungi.
Abstract: Methods were established for growth, sporulation and storage of Septoria nodorum . Following mutagenesis with ultraviolet light or nitrosoguanidine, auxotrophic mutants were isolated in two parent strains by screening survivors on minimal and supplemented media. Pairs of phenotypically-different mutants of the same parent strain complemented each other to produce prototrophic mycelia when co-inoculated onto minimal medium. This procedure was used to assign phenotypically-identical mutations to genes. The most extensive of such complementation analyses involved six arginine-requiring mutants which were assigned to five genes. Growth tests on intermediates of arginine biosynthesis with the same mutants gave results consistent with the complementation analysis and revealed three different points of blockage in the arginine biosynthetic pathway. Spontaneous mutants resistant to potassium chlorate were isolated in five strains by plating pycnidiospores onto chlorate-containing medium. Five phenotypes were distinguished amongst these mutants by growth tests on various nitrogen sources; four of these phenotypes were unable to utilize nitrate. Complementation analysis of these nitrate non-utilizing mutants revealed that at least six different genes were involved. The phenotypes and genetic basis of these chlorate-resistant mutants resemble those in Aspergillus nidulans and Neurospora crassa , suggesting that nitrate assimilation in S. nodorum is similar to the well-characterized process in these other fungi. The mutants isolated are being used in investigations of the pathogenicity and genetics of S. nodorum at the molecular, cellular and population levels.
47 citations
TL;DR: Mutant instability in Septoria nodorum was investigated by comparing reversion rates of spontaneous and mutagen (NTG)-induced mutants, and all the NTG-induced mutants reverted to wild type, while only half the spontaneous mutants in the same genes reverted.
Abstract: Mutant instability in Septoria nodorum was investigated to determine its likely cause by comparing reversion rates of spontaneous and mutagen (NTG)-induced mutants Nitrogennon-utilizing mutants were selected for this by screening for resistance to chlorate All the NTG-induced mutants reverted to wild type, while only half the spontaneous mutants in the same genes reverted Possible explanations and the significance of the phenomenon to this pathogen are discussed
13 citations