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

• Published in: Theoretical and applied genetics Vol. 89; no. 7/8; pp. 838 - 846
• Main Authors: Garber, E.D, Ruddat, M
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-12-1994; Berlin
• Subjects: Biological and medical sciences; Classical genetics, quantitative genetics, hybrids; colonies; color; crossing; Fundamental and applied biological sciences. Psychology; fungal anatomy; fungal spores; Genetics of eukaryotes. Biological and molecular evolution; morphological altered sporidia; mutants; mutation; one mating type strains; phenotype; pigmentation; strains; teliospores; Thallophyta, bryophyta; transposons; two mating type strains; Ustilago violacea; Vegetals; Fungi; Plant pathogen; Sporulation; Basidiomycetes; Transposable element; Mutation; Mating type; Ustilago violacea; Thallophyta
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/BF00224506

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 non-parental color and (2) nonsectored colonies with the non-parental 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.