UBC Theses and Dissertations
Somatic recombination in Ustilago hordei during the parasitic phase on barly Megginson, Fiona Gertrude Ariel
The question investigated in this study was whether or not somatic recombination can occur in Ustilago hordei whilst it is in the parasitic phase on barley. The investigation was carried out in two parts. In the first and major part, barley seeds were inoculated artificially with mixtures of nutritionally deficient mutants of U. hordei. This was done in such a way that infection of the mature plants could only occur if at least one recombination event had taken place asexually, between at least two infective dikaryons, prior to teliospore formation. One smutted plant was found. Detailed analysis of the teliospores from this infection was carried out. The second part of the study was designed to demonstrate that more than one infective dikaryon can simultaneously occupy the host. Again, mixtures of nutritionally deficient mutants were used to inoculate barley seeds but this time so that the origin of teliospores from any infection could be traced back to the parental types in the infective dikaryon. It was concluded that somatic recombination can in fact occur whilst the fungus occupies the host tissue.