Transfer of micronuclei-like structure of Trichoderma reesei QM 9414 into protoplasts of Saccharomyces cerevisiae

Abstract

Minute nuclei, i.e. the ‘smaller nuclei’, were generated when the mycelia of a cellulase producing fungus, Trichoderma reesei QM 9414, were incubated for over 24 h at 40°C or 50°C. The average DNA content of the isolated ‘smaller nuclei’ was about quarter of that of the isolated normal nuclei. This means that the ‘smaller nuclei’ obtained here were not the nuclei condensed by higher temperature. When the normal nuclei were used for the karyoduction into protoplasts of Saccharomyces cerevisiae, no yeast colonies which were capable of proliferation on the solid medium containing CMC-Na appeared after the regeneration. However, when the ‘smaller nuclei’ were used, the regenerated colonies could grow on the solid medium containing CMC-Na. The ‘smaller nuclei’ may be applicable for gene transfer in microbes.