Characterization of Factors Affecting Activity of Chitinase Produced by Mycoparasite Coniothyrium minitans

Coniothyrium minitans is an important mycoparasite of Sclerotinia sclerotiorum(Lib.) de Bary,the causal agent of Sclerotinia stem rot of oilseed rape.In order to elucidate the role of chitinase produced by C.minitans in mycoparasitism on S.sclerotiorum,the factors affecting the chitinase activity of the C.minitans chitinase were characterized in this study.Results showed that the activity of the C.minitans chitinase was highest at 50 ℃ and pH 8.0.The enzyme was stable when the ambient pH ranged from 5.0 to 9.0,whereas lost its activity when it was treated at 60 ℃ for 10 min.The activity of the chitinase was significantly improved by some ions including Mg2+,Fe2+,Ca2+,Ba2+ and Mn2+,while it was significantly suppressed by Zn2+ and Cu2+.The activity of the C.minitans chitinase was enhanced by boric acid at 50～100 mmol L-1 and oxalic acid at 2～8 mmol L-1.The importance of these factors in mycoparasitism of C.minitans on S.sclerotiorum and their potential applications in biological control of the pathogen were discussed in this paper.Fig 6,Tab 1,Ref 19