Efficient agrobacterium-mediated transformation of Shiraia bambusicola and activation of a specific transcription factor for hypocrellin production

Shiraia bambusicola, as a well-known medicinal and edible macro-fungus, is generally located on the branches of bamboo and plays an important role in herbal treatment. Furthermore, the natural products from its fruiting bodies, hypocrellins, are attracting increasing amounts of attention due to their notable bioactivities. In this report, we focused on constructing a fast and universal transgenic system for S. bambusicola, which could easily regulate the biosynthesis of hypocrellins by altering gene expression. By the consideration of the broadened application of the mycelial transformation, it was determined to implement the Agrobacterium tumefaciens-mediated transformation (ATMT) technique, and a transcription factor (SbTF1) was employed to activate the downstream genes in different producing strains. After real-time polymerase chain reaction analysis, gene SbTF1 was verified to be overexpressed in all of the transgenic strains, and the yield of hypocrellins was significantly improved in strain CNU103846. To confirm the regulated function, the transcript levels of the downstream genes and the corresponding products at different stages were screened. In this study, we developed a stable and easily available assay for genetic transformation of S. bambusicola and employed the method to demonstrate that one transcription factor SbTF1 could effectively increase the yield of the final products.