Enrichment of mutants of Rhodosporidium toruloides by the use of inositol starvation

Abstract

(Beceived M a y 2, 1985)Inositol-requiring mutant,s of strains of Rhodosporidium toruloides were isolated and the frequency of isolation of auxotrophic and catabolic mutants from them was measured after starvation for inositol. Mutants can be isolated a t frequencies up to 31 times greater than those of nintagenized cultures without enrichment. Enrichnient for purine and aniino-acid auxotrophs of R. toruloides using the antibiotic nystatin (SNOW 1966) was unsuccessful in our hands even though the method has been used in the selection of mutants of Rhodotorula mucilaginosa (COOK 1974) and of Bhodotorula graminis (DURHAM et al. 1984) unable to utilize certain carbon sources. We therefore turned to the use of starvation for inositol which has been used with success in another basidiomycete, Ustilago niaydis (HOLLIDAY 1962), as well as in the yeast Saccharomyes cerevisiae (HPNRY et al. 1975). Rhodosporidium toruloides Materials and nicthodsOrganisms : The prototrophic yeast-like strain MRE333 (received as R. glutinis) was shown to mate with 11. toruloides strain I F 0 0880 of mating type a, (BANNO l967), to form a dikaryotic mycelium conttining clamp connexions. It is thus a ycast cell of R. toruloides mating type A.Methods: Complementation tests, mutagenesis with ethyl metlianesulphonate (EMQ), and other manipulations were carricd out by standard methods (SHERMAN et al. 1980) except that complete mcdium was mcdium YS (ABE etal. 1975) supplemented with amino acids and purines a t 100 mg 1-l; minimal medium lacking inositol was according to BANNO (1967) ; other minimal media were according to GILBERT and TULLY (1982). Media contained inositol a t a concentration of 2 mg 1-1 where required. Hcsults and discussionThree inositol auxotrophs were isolated as indicated in Table 1 after iiiutagenesis with EMS ( HENRY et al. 1975), outgrowthin inositol-containing minimal iiiediuin and replica plating t o niiniinal niediuiii with and without inositol. The diploids formed by con-

A multi-omic map of the lipid-producing yeast Rhodosporidium toruloides

“…The robustness of lipid production by the basidiomycetous fungus R. toruloides has been well-documented 10 14 38 . Auxotrophic mutants were achieved by physical and chemical mutagenesis 39 , and efficient transformation of R. toruloides with artificial plasmids has been demonstrated 40 . The current study disclosed the genome of R. toruloides based on deep sequencing and RNA-seq-assisted annotation, and further transcriptomic and proteomic analyses provided integrated information to discuss, for the first time and in much more detail, the molecular mechanism of fungi oleaginicity, nitrogen metabolism and the relationship between these processes.…”

Attachment of the Yeast Rhodosporidium toruloides Is Mediated by Adhesives Localized at Sites of Bud Cell Development

“…To investigate the possible adhesion mechanism(s) of leaf surface yeasts, we chose as a model system the basidiomycetous yeast Rhodosporidium toruloides Banno (anamorph, Rhodotorula glutinis [Fresenius] Harrison), a common component of phylloplane communities (9). Unlike A. pullulans, about which little is known genetically, R. toruloides is haploid and amenable to mutagenesis (42). It has exhibited biological control potential against Botrytis cinerea on the phylloplanes of tomato and bean (15) and on apple fruit surfaces during postharvest storage (18).…”

Four Inducible Promoters for Controlled Gene Expression in the Oleaginous Yeast Rhodotorula toruloides

“…To investigate controllable mutant rescue the R. toruloides leu2 mutant strain NCYC 1585 was used ( Tully, 1985 ; Lin et al, 2012 ). The EGFP gene in vector pEGFP-Rt-YR-G418 was replaced by LEU2 from R. toruloides CBS 14 to give plasmid pLeu-Rt-YR-G418.…”

“…Rhodotorula toruloides wild-type haploid strain CBS 14 ( MAT-A1 ; ATCC 10788, IFO 0559, MTCC 457; ( Rennerfelt, 1937 )) and NCYC 1585 ( MAT-A2 leu2 - ino ; ( Tully, 1985 )), were obtained from the Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands and The National Collection of Yeast Cultures, Norwich, UK, respectively. NCYC 1585 is a mutant derivative of wild-type haploid strain CBS 349 ( MAT-A2 ; ATCC 10657, IFO 0880).…”