Identification Of Endophtic Actinomycetes S-42 And Testing Its Antimicrobial Activity To Fusarium Oxysporum

Cucumber fusarium Wilt which caused by Fusarium oxysporumf.Sp.cucumerinum, is a common and destructive disease of cucumber in north of China, especially in greenhouse. Endophytic Actinomycetes as an impotant microbiolgy resource can produce biocontrol agents,which have antifungi anctivity. This research aimed at screening of antagonistic endophytic Actinomycetes with biocontrol effect on this disease.(1) Eleven Actinomycetes strains were firstly screened from eighty medicinal plants endophytic actinomycetes strains by primary screening of dual culture and ferment filtrate inhibitory ability.Strain S-42 had intense antifungal activity of all the candidate strains.(2)Antimicrobial spectrum of the candidate strain S-42showed that streptomyces strain S-42 had intense antifungal activity to 6 kinds of plant Pathogens,three kinds of bacteria (E. coli, S. aureus, B. subtilis) and S. cerevisiae. Strain S-42 have great biocontrol anctibity.(3) Screen optimal culture condition for strain S-42.The result showed the optimal carbon was glucose,the optimal nitrogen was yeast extract respectively, Fe2+ had bad effect for it produccing biocontrol agents.The optimal fermentation pH is 7.0.The optimalfermentation culture time is 6 days.(4)The greenhouse experiment showed that the number of infected plantlets reduced 35% by using strain S-42,at the same time strain S-42 can promote cucumber growing.(5)According to its culture morphological,physiological,biochemical characteristics and analysis of the 16S rDNA,strain S-42 was identified as Streptomyces rubrolavendulea, and it was clustered to Streptomyces rubrolavendulea in the Phylogenetic tree.