Abstract: By using dual culture technique, a strain of endophytic actinomycete named SCF-18 was screened out and isolated from Perinereis aibuhitensis collected from the Huanghai and Bohai Sea, and the bioactivities of the actinomycete against pathogenic fungi were determined. The strain SCF18 showed significantly antagonistic activities to both Rhizoctonia solani and Bipolaris sorokiniana, particularly more potent to R. solani with the maximum inhibition rate of 89.78%. The fermentation filtrate of SCF-18 could inhibit the growth of R. solani in a dosedepended manner. Furthermore, the fermentation filtrate of SCF-18 in 50% concentration showed the maximum growth inhibitory effects to R. solani and H. sativum with inhibition rates of 89.78% and 80.26%, respectively. The optimum growth condition for SCF-18 was at 30 ℃ with pH 7. The highest tolerance of salinity of SCF-18 was 5%. Based on the analysis of morphology, cultural characteristics, physiological and iochemical properties, and 16S rDNA sequencing, the SCF-18 was identified as Streptomyces lavendula. Our results suggest that the strain SCF-18 could be valuable in the biocontrol of R. solani.

Key words: environmental temperature, seed vigor, wheat., seed development