Inhibition And Control Effects Of The Extract Of Trichoderma Harzianum Fermented Broth Against Rhizoctonia Solani And Isolation Antifungal Components From Fermented Broth

In this study, we determined the inhibition and control effects of the ethylacetate extract of Trichoderma harzianum fermented broth against Rhizoctoniasolani.To develop a high-speed counter-current chromatography method and identifythe major antifungal components against Rhizoctonia solani isolated fromTrichoderma harzianum broth which was extracted with ethyl acetate. The HSCCCconditions were optimized and a two-phase solvent system containing n-hexane/ethylacetate/methanoL/water (7:3:5:5,v/v/v/v) was selected for a further investigation.Results described as follows:1. The antifungal activity of the ethyl acetate extract of T. harzianum fermentedbroth was evaluated against Rhizoctonia solani. It was found that the extract couldinhibit mycelial growth （EC50=3.3mg.L-1,EC90=14.4mg.L-1）of Rhizoctonia solani.Greenhouse pot experiments showed that the extract also had significant (P<0.05)protective （7d,79.8%）and therapeutic（7d,63.4%） effects at the concentration of272.1mg.L-1,and the effects can last a long period(21d,protective effects:65.0%,therapeutic effects:63.6%).Whats more, the research showed that the ethylacetate extract of T.harzianum fermented broth had better protective effects thantherapeutic effects. In conclusion, the results suggest that the ethyl acetate extract ofTrichoderma harzianum fermented broth has great potential to develope into biologicalpesticide.2.To develop a high-speed counter-current chromatography method and identify the majorantifungal components against Rhizoctonia solani isolated from Trichoderma harzianum brothwhich was extracted with ethyl acetate. The HSCCC conditions were optimized and a two-phasesolvent system containing n-hexane/ethyl acetate/methanoL/water (7:3:5:5,v/v/v/v) was selectedfor a further investigation. One pure and active compound was elucidated as trichodermin (4mgout of324.3mg of the ethyl acetate extract)using Nuclear Magnetic Resonance(NMR) andFTICR mass spectroscopy.Trichodermin exerted a potent activity in vitro against mycelial growthof Thanatephorus cucmeris (EC50=0.69μg.mL-1, EC90=3.02μg.mL-1). In conclusion,thepresent study suggested T. harzianum produced a number of antifungal compounds against R. solani, including trichodermin, which can be simply isolated usingHSCCC.