Protoplasts were washed twice with 1.2 M sorbitol and resuspended in a regeneration medium. Table 1 shows the results of protoplast fusion experiments as measured by complementation on plates of minimal medium. The frequency of fusion was determined as the ratio between the number of colonies formed on minimal medium and colonies formed on the same medium supplemented with adenine and proline. Table 2 shows the results of a segregation analysis of conidia from six heterokaryons obtained from minimal medium after protoplast fusion. Strains H2, H3, H8, H11, H14 and H15 correspond to heterokaryons obtained by protoplast fusion.
Values are percentages of phenotypes indicated in the table.
Because it is difficult to perform classical genetic studies in P. cinnabarinus , its genome is largely undescribed. An alternative way could be the application of parasexual genetic analysis. Our results indicate that protoplast fusion is an efficient method to conduct genetic analysis in P. cinnabarinus and may be used to study lignin degrading variations in different mutants strains affecting phenol oxidase activities obtained in our laboratory.