Promoter and terminator regions of the pdc gene were acquired from the T. reesei genome sequence (http://genome.jgi-psf.org/Trire2/Trire2.home.html). The pdc promoter (Ppdc, 1305 bp, scaffold 8:106110–107414 bp), the pdc terminator (Tpdc, 721 bp, scaffold 8:103465–104185 bp), and the xyr1 gene (GenBank accession no. AF479644) were PCR-amplified from T. reesei QM9414 genomic DNA using primers Ppdc-F and Ppdc-R, Tpdc-F and Tpdc-R, and xyr-F and xyr-R (Table 1), respectively. Amplified Ppdc, xyr1, and Tpdc fragments were fused by overlap extension PCR using primers Ppdc-F and Tpdc-R, generating a xyr1 expression cassette. This expression cassette was cloned into a pMD 18-T Vector (Takara, Dalian, China), yielding the plasmid pPDC-XYR (Fig. 1a). This plasmid was inserted into the genome of T. reesei RUT C30 for constitutive expression of the xyr1 gene.