Identified For The Plant Pathogenic Fungus Trichoderma Strains Screened And Pepper Antimicrobial Composition

Overusing chemical pesticides not only had caused environment pollution, but also had threaten human health. Research and development of biological pesticides is an important approach to resolve the dilemma of chemical pesticides. China has rich resources of microorganisms and medicinal plants, from which the microorganisms and plants possessing high fungicidal activities can be screened, ingredient which has antifungal activities can be isolated, purified and identified. That can provide lead compounds for the development of biological pesticides. The antifungal activities of several Trichoderma strains were screened, and antifungal mechanism was studied. In addition, the main antifungal ingredient of Zanthoxylum bungeanum Maxim was isolated by activity direction, and the structure of the ingredient was identified. The results are as follows:Through dual culture test, twenty-three strains of Trichoderma's antifungal activity against eight kinds of phytopathogenic fungi, which had been isolated from different regions of Shandong province, has been determined. Trichoderma 09-07 was found best of antifungal activity, A. solani 71.32%, R. solani 69.89%, B. cinerea 58.51% and P. capsici 59.42%, respectively. Phytopathogenic fungi were inhibited through competition and hyperparasitism.Trichoderma 09-05,09-09 and 09-22 have good antifungal substances, their nonvolatile metabolites and volatile metabolites'antifungal activity had been determined by deduction method and disc filter method. Trichoderma 09-09's metabolites has the best of antifungal activity. Its'nonvolatile and volatile metabolites had all antifungal activity on eight kinds of phytopathogenic fungi, the inhibition rate of nonvolatile metabolites against B. cinerea, A. solani, F. graminearum and R. solani was all more than 70%,90.98%,87.85%,82.74% and 74.90%, respectively. Trichoderma 09-05 inhibited phytopathogenic fungi mainly through volatile metabolites, and Trichoderma 09-22 didn't inhibit some phytopathogenic fungi. Therefore, Trichoderma 09-09 had the value of further study.Two strains of Trichoderma were identified using the morphology and molecular biology method. The results showed that all the two strains were Hypocrea lixli(Trichoderma harzianum).Fungicidal activities of ethanol extract from Zanthoxylum bungeanum Maxim had been determined. When crude extract's concentration was 1 g/L, the fungicidal activity extract against eight kinds of phytopathogenic fungi was all more than 40%. The highest inhibition rate was 65.49% against B. cinerea, The EC50 values was 212.0 mg/L, secondly was 460.5 mg/L against F. graminearum. Liquid-liquid extract was performed to the ethanol extract, and the petroleum ether extract possesed the highest fungicidal activity against 8 phytopathogenic fungi among petroleum ether, ethyl acetate and butyl alcohol extracts, which indicated that main antifungal ingredients were extracted by petroleum ether.The antifungal ingredient from Zanthoxylum bungeanum was isolated and purified under activity direction. Silical gel column chromatography and thin layer chromatography were used to isolate and purify the ingredient, and all the partition's fungicidal activity was tested. Finally, the structure of antifungal ingredient from Zanthoxylum bungeanum was elucidated as 2-Hydroxy-4,6-dimetboxyacetopbenone on the basis of UV, IR, EI-MS,1H-NMR and 13C-NMR data.