Potential biocontrol efficacy of with cellulase expression regulator gene knock-out.

The biocontrol function of the repressor of cellulase expression I (ACE1) in was verified through constructing Δ mutant strain by -mediated transformation. The activities of cell wall-degrading enzymes (cellulase, xylanase, chitinase, β-1,3-glucanase, and protease) in the supernatant of Δ mutant strain were distinctly higher than those of control strain, followed with the elevation of related genes transcript levels. Besides, the Δ mutant resulted in an elevating transcript level of , but no obvious change in the expression of , which suggested that ACE1 was negative regulator of the transcription, but not involved in transcription. On core polyketide synthases of four biosynthesis gene clusters for antibiotic secondary metabolites, only the transcription levels of encoding genes Try83179/TryH and Aza79482/AzaJ in Δ mutant strain were significantly higher than that in wild-type during antagonizing with pathogenic fungi and (with the inhibition rate of 30.7 and 19.8%, respectively). The biocontrol function of Δ mutant strain was remarkably enhanced. The results indicated that ACE1, indeed, acted as a repressor for cell wall-degrading enzymes and PKSs expression in , and the Δ mutant strain effectively made related enzymes activities improved with potential enhancement of biocontrol potency.