Solid State Fermentation Of The Biocontrol Fungus Coniothyrium Minitans Against Sclerotiniose And The Biological Characterization Of Several Strains

The wheat, rice and wheat bran were firstly treated as the solid state fermentation media of biological control fungus Coniothyrium minitans. On the present study, strain Cm-02 of Coniothyrium minitans introduced from Germen was fermented under various conditions to determine the best single fermentation factor, and then they were subjected to orthogonal experiment to determine the best cross fermentation conditions, aiming to provide theoretical base for the industrial production of biological agents originated from Coniothyrium minitans. In addition, the biological characters of two Coniothyrium minitans strains (Cm-c1 and Cm-b2) from Sichuan eco-region were compared with two Germanic strains, Cm-02 and Cm-315. The results were provided in the following sections.The strain Cm-02 was fermented under 20℃on solid wheat fermentation medium in which concentration was 50% (g/ml), and nutritional materials were added before fermentation. The results showed that pH 6.0 was the best for all of the single factors when strain Cm-02 was fermented. The sporulation of each treatment reached the peak in 20 d after fermentation. The orthogonal experiment was conducted with three treatments of each of the three conditions (desirable fraction of water added in the solid medium, time for adding nutrition and pH value). PH 6.0 was the best fermentation condition for srtain Cm-02, and its sporulation reached to the peak in 20 d after fermentation (18.43×10~9 cfu/ml).The biological characteristics of the four strains were significantly different, and the morphological character of strain Cm-c1 was apparently differ from the others. All of the four strains could grown between 5 to 30℃under the pH value range of 2-12, but the best one was pH 6.0 except for strain Cm-c1 for which desirable pH value was 4.0. They were grown best under full lighting while they sporulated best in complete darkness. PDA medium was desirable for the growth and sporulation of Coniothyrium minitans. Strain Cm-c1 of all treatments grown best but its sporulation was the smallest. In addition, the germination capability of Coniothyrium minitans spores reduced with longer fermentation time while promoted with additional nutrition. The inhibition rate of the four fungal strains against Sclerotinia sclerotiorum strain Ya was over 50% on dual culture. The sclerotic parasitism rotting capability of three fungi (Cm-02, Cm-315, Cm-b2) was around 90% and the last one was over 80%, revealing apparent inhibition on the formation of sclerotia. In short, the inhibition capability of the four fungi exhibited nearly the same level. The four fungi could not exhibit the enlargement of oil-rape leaf spots of sclerotinia sclerotiorum M08 strain in vitro.