Intraspecific karyoduction in Trichoderma reesei QM 9414 using the ‘smaller nuclei’

Abstract

The micronuclei-like structure i.e., the ‘smaller nuclei’, and normal nuclei derived from the auxotrophic strains of Trichoderma reesei QM 9414 were transferred to protoplasts of another auxotrophic strain of the fungus. DNA content of the conidia (multinucleate) derived from karyoductants obtained by making use of normal nuclei was almost 4-times larger than that of the original conidia. However, the DNA content of the conidia (mononucleate) generated from karyoductants constructed by using ‘smaller nuclei’ was almost the same as that of the original conidia. Such hybrids could not be obtained by using normal nuclei. A new type of transgenic strain could be constructed by making use of the “smaller nuclei” in karyoduction.