Inhibitory Action Of Endophytic Fungi On Cucumber Soil-borne Diseases

Endophytic fungus is a kind of widespread microorganism in plants. They can symbiotic with plants, without causing plant diseases. They have important economic significance on improving the resistance of plants, yield and product quality. First, screening good fungi strains which have inhibitory effect on soil-borne diseases. We study the inhibition of some endophytic fungi fermented liquid on three kinds of cucumber soil pathogenic fungus. Also extract the active material from one of the strains, study the inhibition of active substances on three kinds of cucumber soil pathogenic fungus. The main results of this study are as follows:1. From 88 strains screened five strains have inhibition effect on Fusarium root Wilt, ten strains have inhibition effect on Rhizoctonia root rot, and sixteen strains have inhibition effect on Sclerotinia root and stem rot, 25 strains in all. They belong to nine genus, they are Penicillium, Fusarium, Aspergillus, Trichoderma, Neocosmospora, Myrothecium, Colletotrichum, Epicoccum and Alternaria.2. Compared the inhibition of endophytic fungus stains in sterilizated substrate and non-sterilizated substrate pot experiment. The result indicated that some endophytic fungus strains had no different inhibition in two kinds of substrate. And the inhibition of some endophytic fungus strains was lower in non-sterilizated substrate than sterilizated substrate.3. By antimicrobial experiment of endophytic fungi fermented liquid on threekinds of cucumber soil-borne diseases, screened 4 stains had good inhibition onFusarium oxysporum f. sp. Cucumerinum, 2 stains had good inhibition onRhizoctonia solani, and 2 stains had good inhibition on Sclerotinia sclerotiorum.These stains also had inhibition on relevant pathogenic fungus with the 40%fermented liquid concentration.4. Use the stain F83 which had good inhibition on three kinds of cucumber soil-borne diseases as material, by extracting, separating and purificating, wo got 7componds which had antimicrobial activity to pathogenic fungus. These compondsalso had obvious inhibition on relevant pathogenic fungus with the concentration ofthese compounds between 0.05 mg/mL and 0.1 mg/mL.