Cloning and prokaryotic expression of the glucanase gene Glu1 from Trichoderma asperellum

A 984-bp glucanase gene (Glu1) was cloned from Trichoderma asperellum ACCC30536, and was found to encode a sequence of 327 amino acids. The Glu1 protein, which belongs to the Glyco-hydro-12 family, is predicted to be a β-1, 4-glucanase. The Glu1 amino acid sequence has 91% identity and the closest relationship with the Glyco-hydro-12 family protein XP_013940397.1 of T. atroviride IMI 206040. Using qRT-PCR analysis, Glu1 expression levels in T. asperellum were monitored under nine different induction conditions, which indicated that Glu1 may participate in the recognition between T. asperellum and poplar or poplar fungal phytopathogens. A prokaryotic expression vector was successfully constructed and a recombinant protein rGlu1 was obtained. Enzyme activity analysis indicated that the optimum pH and temperature for rGlu1 activity is 4.5 and 45 ℃, respectively, and that rGlu1 activity gradually increases with a prolongation of induction duration up to 5 h.