Rational Engineering of Talaromyces sp. into a High-Performance Cellulase Producer via a Novel Transcriptional...

Filamentous fungi employ complex regulatory systems involving transcription factors (TFs) to control cellulase gene expression. Talaromyces sp. are potent cellulolytic fungi; however, research on their TFs remains in the early stages. Here, a novel TF, Te18280, was identified from the highly cellulase-producing strain Talaromyces endophyticus NEAU-6. Te18280 is stably expressed and localized in the nucleus, acting as a transcriptional activator of cellulase genes. Overexpressing Te18280 (OE-Te18280) significantly increased enzyme activities (FPase: + 86.00%, CMCase: + 25.64%, pNPCase: + 56.10%, β-glucosidase: + 45.79%, xylanase: + 27.02%) and improved strain phenotypes, including increased colony diameter, higher dry weight, and greater hyphal branching. RT-qPCR and EMSA analyses confirmed Te18280 specifically binds to cellulase gene promoters to upregulate their transcription. Furthermore, overexpressing Te18280 in a △TeSrdA background generated a double recombinant strain with superior enzyme production, reflecting an additive effect between the two genetic modifications. This study elucidates the function of Te18280 and demonstrates the potential of engineering fungal strains to enhance cellulase production.