Competitive binding of TeXlnR and TeAmyR regulates cellulase production in Talaromyces endophyticus

Efficient cellulase production is essential for its application in green bioprocessing, yet the transcriptional regulation of cellulase biosynthesis in <i>Talaromyces</i> sp. remains largely uncharacterized. In this study, we elucidate the regulatory functions of TeXlnR and TeAmyR in <i>Talaromyces endophyticus</i>. Our results demonstrate that TeXlnR, as a potent transcriptional activator, enhances enzyme production by over 33 %. RNA-seq analysis shows that <i>TeXlnR</i> overexpression upregulates 33 cellulase genes and 11 hemicellulase genes, while concurrently repressing the expression of the transcription factor <i>TeAmyR</i>. Further investigation identified TeAmyR as a repressor of cellulase production in <i>T. endophyticus</i>. EMSA and yeast one-hybrid analyses confirmed the specific competitive binding of these two transcription factors to the promoter regions of cellulase genes <i>eg5B</i> and <i>eg12A</i>. TeXlnR both directly activates target gene transcription and indirectly promotes cellulase synthesis by downregulating <i>TeAmyR</i> expression to reduce its competitive binding to promoters. These findings provide direct evidence for competitive regulation by transcription factors in <i>Talaromyces</i> sp. and establish a theoretical foundation for the rational engineering of industrial strains with improved cellulase production.