The antifungal proteins of antagonistic strains NCD-2,B-101,DHT-13,BDT-25,JJ-134,JJ-102 and 80b-2 isolated from the soil infected with Verticillium dahliae were obtained from their fermentation filtrates through precipitation with 75% ammonium sulfate salting out.Antagonistic activities of the proteins were determined via cylinder-plate method.Results indicated that antifungal proteins from 80b-2,NCD-2,DHT-13 and B-101 had higher specific activity,of which B-101 and NCD-2 could produce clear inhibition zone.Antifungal protein of B-101 strain was obtained by using the salt fractionation.It was found that protein precipitated with 20%-30% saturation ammonium sulfate could produce transparent and bigger inhibition zone,thus it had obvious antifungal activity.Furthermore the antifungal protein was separated by DEAE-cellulose chromatography.An antifungal protein fraction named RFP-6 was obtained,which showed definite inhibition activity against Verticillium dahliae.Its molecular weight was approximately 14.4 kD as determined with SDS-PAGE.
