Random amplified polymorphic DNA analysis of Ustilago violacea.

Isolates of the two mating type strains of the basidiomycete phytopathogen Ustilago violacea (Pers.) Roussel [a.k.a Microbotryum violaceum (Pers.:Pers.) Deml and Oberw] are restricted in their host range to one or a few species of Caryophyllaceae (Pinks). Molecular genetics maps in this species are commonly constructed by analyzing the segregation of restriction fragment length polymorphisms (RFLPs) among the progeny of a sexual cross and more recently through electrophoretic karyotypes and chromosomal polymorphism using CHEF gel analysis. However, currently, polymorphisms in genomic fingerprints generated by arbitrarily primed polymerase chain reaction (PCR) can distinguish between strains of almost any organism, which is useful in genetic mapping. The objective of this project was to use PCR technology, 40 Operon 10-mer primers, and 5 simple sequence repeat (SSR) primers, designed on microsatellite sequences to determine their efficiency in detecting intraspecific differences between the genomic DNA of the two mating type strains of U. violacea (a1 and a2). Polymorphism in the banding patterns of the DNA samples was detected after PCR and electrophoresis in 1.4% agarose gels. This polymorphic intraspecific variation will be utilized to detect cryptic and trans-active transposable elements in U. violacea.

Genetics of Ustilago violacea. XXXII. Genetic evidence for transposable elements.

Crosses between Ustilago violacea mutant strains with different color phenotypes that were derived from the 1.A1 and 2.A2 laboratory strains yielded, as expected, bisectored teliospore colonies with the parental colors as well as the a-1 and the a-2 mating-types. Generally, wild teliospore collections usually produced sporidia of both mating-types, providing two-mating-type (TMT) strains. Occasionally, however, sporidia with only one mating-type allele, a-1 or a-2, were obtained from teliospores, providing one-mating-type (OMT) strains. Crosses between OMT and laboratory strains with different color phenotypes gave (1) bisectored teliospore colonies with the parental colors or colonies with a parental color and a nonparental color and (2) nonsectored colonies with the nonparental color or with the parental color. The frequencies for the occurrence of non-parental color ranged from 41% to 93%, depending on the strain. The yield of teliospore colonies was usually reduced for these crosses. In many of these teliospore colonies, morphologically-altered sporidia (MAS phenotype) were observed. The morphology and the size of the sporidia with the MAS phenotype differed from those of teliospore colonies of the crosses between the laboratory strains. In addition, these sporidia did not form conjugants. A cross involving the TMT strains C449 yielded the MAS phenotype as well as a high incidence of tetrad colonies with a nonparental color. The high degree of instability of the parental color phenotypes, and the high frequency of the appearance of nonparental color phenotypes as well as the appearance of the MAS phenotype, are in accord with the presence of active and inactive transposable elements in the OMT strains, TMT strains, and laboratory strains.

Spontaneous and induced mitotic recombination in Ustilago violacea detected at the cellular level.

Spontaneous and induced mitotic recombination in the heterobasidiomycete Ustilago violacea was detected at the cellular level using a sporidial morphology mutation. Mitotic recombination was induced by ultraviolet light (UV), nitrogen mustard (NM) and metabolically nonactivated cyclophosphamide (CP). The effects of low (14 °C) and high (30 °C) temperature and culture age on induced mitotic recombination are reported. Low temperature after inductive treatment uniformly reduced mitotic recombination. High temperature increased UV induced recombination, had no effect on NM-induced recombination and reduced CP-induced recombination to the spontaneous level. Temperature alone had no effect on mitotic recombination. Ultraviolet light-induced recombination was correlated with the rate of cell division and cell survival as cells passed from log to stationary phase growth. Detection of mitotic recombination at the cellular level is discussed as a method to assay postreplication repair of genetic damage and as a screen for agents which induce genetic damage in eukaryotic cells.

The genetics and biochemistry of urease in Ustilago violacea.

Two complementing loci in different linkage groups of the basidiomycete Ustilago violacea are involved in urease activity: a structural one (ure-1) and a second inferred to involve a permease (ure-2) locus. Two types of complementing mutations occur in the structural locus: null activity (ure-la) and obviously reduced activity (ure-1b). The ure-2 mutants lacked urease activity in vivo on the phenol red-urea est medium, but gave extracts with wild-type activity. Extracts from wild-type strains gave one site of urease activity after polyacrylamide gel electrophoresis. A number of ure-1b mutants and activity revertants from ure-1a mutants yielded electrophoretically variant urease sites. The results are discussed in terms of enzyme polymorphism in haploid eukaryotes by one (missense) or two (null, then missense) mutations.

Blastomycosis: specificity of antigens reflecting the mating types of Ajellomyces dermatitidis.

In a study of sera from patients with proven or suspected blastomycosis, positive immunodiffusion tests were obtained in all active cases when fresh sera were tested with a cell sap (CS) antigen. False negatives occurred on occasion when an ethanol precipitate (EPF) antigen was used alone. No false positives were found. The CS antigen from the (+) mating type had in common two lines of identity with the (CS) antigen of the (-) type. In addition, other lines were present when the patient was infected with the same mating type as was used for the preparation of the antigen. No differences in the electrophoretic patterns of the enzymes leucine amino peptidase or phosphatase were noted when preparations from the two mating types were compared. However, a distinct pattern was noted when the alpha esterases of the (+) and (-) mating types were examined. Specific alpha esterase antibodies were present in patients' sera.