Auxotrophic mutants of the yeast Trichosporon adeninovorans

Abstract

We have isolated and characterized auxotrophic mutants of Trichosporon adeninovorans, strain PAR-4 to get genetic markers that cover the entire nuclear genome of this thermotolerant yeast of technological interest. The nitrosoguanidine mutagenesis yielded mutants at a high frequency. We detected a broad spectrum of auxotrophic phenotypes in the random mutant samples. Obviously, strain PAR-4 is a haploid or hyperhaploid yeast. In correspondence we determined a low DNA content per cell. In contrast to NG1), UV light was an inefficient mutagen. UV survival curves were without the typical shoulder indicating suppression of repair of UV-induced lethal lesions. Thus, the response of PAR-4 to UV was different from those of Saccharomyces cerevisiae and other yeasts.

A history of research on yeasts 10: foundations of yeast genetics1

“…Sphaeroplast fusion has been used for genetic mapping41. A number of auxotrophic mutants have been obtained and the yeast appears to have four chromosomes42, 185, 323, 324 (for reviews, see37, 380).…”

A set of genetic markers for the chromosomes of the imperfect yeastArxula adeninivorans

“…Auxotrophic mutants were isolated after induction of mutations with N-methy1-N'-nitro-N-nitrosoguanidine or UV-light and characterized by auxanography tests and enzyme assays (Samsonova et al, 1989). Allelic relationships between several mutations were investigated in complementation tests.…”

“…Yeast cells of A. adeninivoruns contain similar amounts of DNA to haploid cells of Saccharomyces cerevisiae and other ascomycetous yeasts (Samsonova et al, 1989;Gienow et al, 1990). These findings are convincing arguments for haploidy together with the relatively high frequency of auxotrophic mutants with a broad spectrum of phenotypes isolated after nitrosoguanidine mutagenesis (Samsonova et al, 1989) as well as the nuclear DNA quantity and genome size (Gienow et al, 1990).…”

Generation of genetic recombinants in Trichosporon cutaneum by spontaneous segregation of protoplast fusants

“…Leucine-requiring mutants were isolated in T. cutaneum by Stepien et al (1 988), and successful genetic transformation and gene cloning have been described recently (Glumoff et al, 1989;Ochsner et al, 1991). Isolation of a variety of auxotrophic mutants in Trichosporon adeninovorans has also been reported (Samsonova et al, 1989).…”