Fig. 1

a Schematic description of the knockout of gene 121121 by homologous recombination using plasmid pXBthg-121121 (Additional file 1: Fig. S1). b PCR cloning of the gene fragments 3783 bp and 2075 bp as shown in a from T. reesei RUT-C30 and the recombinant strains ZC121-1, ZC121-2, ZC121-3, and ZC121-4. c Cellulase and hemicellulase activities in the culture supernatant of T. reesei RUT-C30, ZC121-1, ZC121-2, ZC121-3, and ZC121-4 grown on 2% cellulose were measured on day 5, including the activities of FPase (the filter paper activity), pNPGase (the BGL activity), pNPCase (the CBH activity), CMCase (the CMC activity), and pNPXase (the β-xylosidase activity). Meanwhile, d the corresponding yellow pigment production was determined by measuring the absorbance at 370 nm. The error bars indicate the standard deviations of three biological replicates