Study on antifungal mechanism of endophytic actinomyce Lj20 extracts.

【Objective】 The study was to realize antifungal mechanism of endophytic actinomyces Lj20 extracts.【Method】 The effect of Lj20 extracts(100 mg/L) on mycelia of Botrytis cinerea Pers.was observed.The effects of Lj20 extracts which concentration contained 0.02,0.2,2,20 and 200 mg/L on mycelia growth,spore formation and germination of Botrytis cinerea Pers.,Pestalotiopsis spp.,Curvularia spp and Alternaria solani(Ell.et Mart) Jones et Grout.were measured,and the influence of Lj20 extracts on cell membrane of Botrytis cinerea Pers.was determined.【Result】 After treated with Lj20 extracts(100 mg/L),the mycelia were reduced,crenate and broken.The tuberculate malformation appeared,and the protoplast exosmosed.There was obvious inhibition effect of Lj20 extracts against mycelia growth,spore formation and spore germination of four pathogens,the effect of which was most obvious against Botrytis cinerea Pers.EC50 of inhibiting mycelia growth was 0.96 mg/L,and EC50 of spore germination was 8.33 mg/L.Inhibition rate of 200 mg/L Lj20 extracts against spore formation was 89.4%.Botrytis cinerea Pers.culture fluid treated with 200 mg/L Lj20 extracts had absorption maxima at 260 nm,but the control didn't have.【Conclusion】 Lj20 extracts had inhibition on mycelia morphology and growth,spore formation and germination of four pathogens and had obvious effects on cell membrane permeability.