Studies On Screening Agricultral Antifugal Metabolitis Of Endophytic Fungus Form Celastrus Angulatus

Endophytic fungi are the microbiology associated with living tissues of plants without causing any noticeable symptoms of disease.They constitute a large,special fungal group,and they are to be found in all or almost all plants. Moreover,the secondary metabolites of endophytic fungi are abundant.Studies on endophytic fungi will promote the development of microbial medicine and help the protection of the valuable and rare plants. The aims of this study are to isolate endophytic fungus from Celastrus angulatus and screen the strains that produce agricultural antibiotics, then work about the isolation and identification of active components have been carried out. The main results are as follows:Taking different separating culture medium and isolating methods, 56 strains of endophytic fungi were separated from the bark of Celastrus angulatus.The results indicated that the fermentation products of 5 strains, which numbered 2K3, 2KR6, 2KR7, 1KM8 and 1KR8, had fungicidial activity against Gibberella zeae, Exserohilum turcicum, Botrytis cirerea, Glomerella cingulata, Alternaria longipes and Fusarium coeruleum.he antifungal activities of fermentation products of strain 2K3 were tested. The results showed that the methanol extracts of mycelium had evident fungicidal activity . At the concentration of 1000μg·mL-1, the extracts had more than 85% inhibition rate against Bipolaris sorokiniana, Exserohilum turcicum, Botrytis cirerea, Colletotrichum gloeosporioides, Alternaria longipes and Fusarium coeruleum. The results of pot test indicated that the methanol extracts of mycelium exhibited more than 70% for both protective efficacy and therapeutic efficacy against Erysiphe graminis disease at the 2000 concentration ofμg·mL-1. The optimum composition of culture medium and fermentation conditions of the strain 2K3 were demonstrated respectively. The optimum culture medium original is about pH 7.0. Inoculum volume was 15 entries per 100mL medium. A 250mL flask containing 100mL medium was cultivated at 26℃for 240h and the rotatory velocity was 180 rpm. Under this culture conditions, the product and activity against Bacillus cereus were high than any conditions.By means of observation on aerial mycelium, macroconidia, microconidia and colony morphology characteristics and comprised with related classify system, strain 2K3 was identified as Fusarium.