Complementation analysis with new genetic markers in Phaffia rhodozyma.
Isolation and characterization of auxotrophic mutants from wild-type and astaxanthin mutant strains of Phaffia rhodozyma is described. Differences in survival were observed when u.v. irradiation of P. rhodozyma wild-type and astaxanthin mutant strains were incubated in the dark or exposed to photoreactivating light. Ultra-violet mutagenesis was not effective to produce auxotrophic mutants in this yeast. Auxotrophic mutants were obtained with high efficiency through a nystatin enrichment procedure after a N-methyl-N'-nitro-N-nitrosoguanidine (NGT) mutagenic treatment with a 0.12% survivor level. Stringent mutagenetic conditions were needed to obtain P. rhodozyma auxotrophs. The most frequent mutants were ade- and met- in a rather narrow auxotroph spectrum. These results may be associated with a possible diploid condition of this yeast. The high number of adenine auxotrophs obtained in relation to other auxotrophic mutants suggests the possibility of some degree of heterozygosity in the wild-type strain UCD 67-385.
Retamales
P
P
Laboratorio de Genética, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
León
R
R
Martínez
C
C
Hermosilla
G
G
Pincheira
G
G
Cifuentes
V
V
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D005816:Genetic Complementation Test; D005819:Genetic Markers; D008027:Light; D003904:Mitosporic Fungi / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D016296:Mutagenesis; D009761:Nystatin / Q000494:pharmacology; D014466:Ultraviolet Rays; D024341:Xanthophylls; D015003:Yeasts / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000096:biosynthesis
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D005819:Genetic Markers; D024341:Xanthophylls; D019207:beta Carotene; D009761:Nystatin; C005948:astaxanthine