Expression and Functional Characterization of Chitinase Gene, CHI58 Related to Biocontrol in Chaetomium cupreum

A novel chitinase (chi58) was cloned from Chaetomium cupreum, an important biocontrol fungus. The temporal expression of chi58, in response to the treatments of cell walls of three pathogens, was measured in C. cupreum using RT- PCR. The expression of chi58 can be highly induced by exposure to the cell walls of plant pathogens, suggesting a role in plant disease resistance. The chi58 gene was inserted into the vector pPIC9K for extracellular expression in the methylotrophic yeast GS115. To improve the efficiency of expression of the recombinant pPIC9K-chi58 in P. pastoris, we performed the mutation at five positions, and expression levels of the chI58Alte have been shown to be enhanced 3-fold. The inhibition variance of the P. pastoris that expressed the chi58Alte was between 28% and 48%. The chitin-binding domain is important for chitinase binding to the colloidal chitin.