Inter-mating type protoplast fusion in the zygomycete Absidia glauca

Methods for obtaining the release, regeneration, and fusion of protoplasts from the dioecious zygomycete Absidia glauca are presented. Somatic hybridization was obtained between protoplasts from several amino acid auxotrophic mutants either belonging to the same or complementary mating type. Both kinds of mating type information are expressed within the same organism and give rise to a monoecious phenotype. Without the selective pressure on the auxotrophic markers used for the construction of the fusion strains, the ability to form zygospores is rapidly lost. However, the gene clusters for ribosomal RNA which are distinguishable between mating types are stable and maintained in the fusion strains, independent of growth conditions.