Antagonism Against Plant Diseases Of Secondary Metabolites And The HPLC Detection Condition Optimization Of Active Components From Chaetomium Globosum ND35

Endophytic fungi is existed in the various tissues and organs of pyphae plants inside at a certain stage of its life history or all of the stages, which does’t cause significant symptom of plant diseases. Because it is able to produce secondary metabolites to control plant diseases, now it is serving as an important biological control agent.In this study, the endophytic fungus Chaetomium globosum ND35was isolated from healthy plants Populus tomentosa. The crude extracts of secondary metabolites were obtained by liquid fermentation after the organic solvent extraction. Then preliminary separation of active components were gotten by TLC. Antifungal activities and the spore germination were investigated with the crude extracts and fractions on pathogenic Bipolaris maydis, Botrytis cinerea, Phytophthora capsici. The result showed that:1. both the crude extracts and fractions had good antifungal activity, and the inhibitory effect was gradually increased with increasing concentrations. Inhibition rate of the crude extracts which concentration is4.0mg/ml on the Bipolaris maydis is40.4%, on Botrytis cinerea is32.8%, on Phytophthora capsici is28.5%. Inhibition rates of the fraction A、B which concentration is4.0mg/ml on Bipolaris maydis are37.8%%、42.2%, on Botrytis cinerea are42.8%、51.6%, on Phytophthora capsici are34.8%、25.0%.2.Under the microscopic observation, the pathogenics’ vegetative hyphae in the medium were obviouly swelling, deformity, and bifurcation increased compared with the control treatment. The vegetative mycelium of Control group phytophthora capsici was also changed because of the acetone.3.Spore germination tests on Bipolaris maydis, Botrytis cinerea, Phytophthora capsici showed that crude extracts and fractions inhibit the germination of spores. After germination, Bipolaris maydis’germ tubes were expand and deformed. With different concentration of treatment solutions, germ tubes had different lengths. Part of the spores of Botrytis cinerea germinated. When the concentration of crude extracts and fractions’were4.0mg/ml, spore germination rate was100%. Zoospore of Phytophthora capsici is sensitive to the metabolites. Some zoospore is dissolved.4.Control disease experiment in greenhouse was conducted with fermentation and crude extracts of Chaetomium globosum ND35on corn leaf blight, cucumber gray mold, pepper phytophthora blight. The result showed that the control effect on corn leaf blight is75.8%, on cucumber gray mold is49.1%. on pepper phytophthora blight is43.6%with the fermentation of Chaetomium globosum ND35. Crude extracts at different concentrations indicated different control effects. Prevention effects are gradually increased with the increased concentration. when the treatment solution concentration is2.5mg/ml, the control effect on corn leaf blight is35.5%, on cucumber gray mold is56.0%, on pepper phytophthora blight is42.2%.5.Optimized the detection condition on the antifungal component of secondary metabolites by HPLC, we found that the best condition:injection volume was20μl, velocity was2ml/min, The mobile phase ratio of acetonitrile and water is65:35. And in accordance with the HPLC chromatogram of crude extracts C and fractions A, B, Speculated the peak time of A, B. B may be a mixture, which contain two peaks. Separated the peaks A, B contained, then verified their antimicrobial activities. The result prove their active. Lay the foundation for the isolation and identification of each peaks.