It was established that gene expression exp1, encoding a specific transcription factor was activated during transition the vegetative to the generative stage of development in cultivating xylotrophic basidiomycete Lentinus edodes (shiitake) on wood substrate. Especially this is characteristic from stage previous of fruiting and connected with the formation of brown mycelial mat. A study showed that exp1 gene transcriptional activity increased 10-fold during formation of the morphological structure, while drop in activity of the gene was marked for primordial and fruiting bodies.