Transcription Factor PdTP1 Regulates the Biotransformation of Limonene to α-Terpineol and the Growth of Penicillium digitatum

α-Terpineol, an alcoholic monoterpene with lilac-like aroma, possesses diverse biological activities and has found applications in the food, pharmaceutical, cosmetic, and agricultural industries. Our previous studies indicated that gene PdTP1 was highly expressed in Penicillium digitatum DSM 62840 during the biotransformation of limonene to α-terpineol, while its actual biological functions are not fully understood. Here, PdTP1 was functionally characterized with bioinformatics analysis, subcellular localization, transcriptional activation activity, overexpression, and RNA interference (RNAi) silencing and RNA-seq analysis. Results showed that PdTP1 protein contained a GAL4-like Zn2Cys6 DNA-binding domain and a fungal_trans domain, was located in the nucleus and cell membrane and presented transcriptional activation effect, suggesting that PdTP1 encoded a Zn2Cys6 type transcription factor. Overexpression of PdTP1 in P. digitatum promoted limonene biotransformation and increased α-terpineol production, and opposite results were observed after the silencing of PdTP1. Moreover, transcription factor PdTP1 was found to affect the growth of P. digitatum and participate in ionic stress and oxidative stress responses. RNA-seq data revealed that altering the PdTP1 expression influenced the expression of some genes related to terpene metabolism or biosynthesis, fungal growth, and stress responses. In summary, PdTP1, which encoded a Zn2Cys6 transcription factor, played important roles in improving the production of α-terpineol from limonene and regulating fungal growth and environmental stress responses.