ACE3 as a master transcriptional factor regulates cellulase and xylanase production in Trichoderma orientalis EU7-22

Abstract

As an efficient fungus in secreting cellulase, Trichoderma orientalis EU7-22 has an important value in the degradation of biomass. Compared with other filamentous fungi, it has an important, unique nature, and it deserves intensive study. Therefore, the function of positive transcriptional regulator ACE3 was investigated for cellulase and hemicellulase production in the strain. As the ace3 knockout strain, the Δace3 mutant was constructed by homologous recombination, so that the enzyme activities (FPA, CMC, CBH, BG, XYN) and the extracellular protein concentration in the mutant strain decreased to 17.8%, 8.3%, 0.14%, 1.8%, 6.8%, and 19.2% of the parent strain, respectively. The transcription level of cellulase and hemicellulase genes also decreased significantly. The result of SDS-PAGE demonstrated that the Δace3 mutant only clearly showed a protein band, which was characterized by protein profiling with LC-MS/MS and identified as the GH10 family of xylanases. It was proposed that ACE3 is a main up-regulation transcriptional factor of T. orientalis EU7-22 and expected to be applicable to further genetic modification.