Isolation, Identification And Primary Study Of An Antagonistic Bacterium Strain S-16 Of Sclerotinia Sclerotiorum Of Sunflower

Sclerotinia sclerotiorum (Lib.) de Bary caused a serious disease on Sunflower. In this study, Rhizosphere soilsoil samples from Hohhot, Baotou, Ulanqab, Bayannur, Chifeng, Tongliao and Shanxi Province, Hebei Province, 170 cities and counties and others regions were researched for Antagonistic Bacterium Strains. There are antagonistic effects of various strains of 1 406, accounting for 34.07% total number of strains, including fungi, 1; actinomycetes, 109; Bacillus type bacteria, 867; other types of bacteria, 429 strain. And obtain a culture of confrontation to some extent in the culture medium so that bacteria can not form sclerotia Sclerotinia biocontrol bacteria S-16. Experiments show that the S-16 antagonistic strains of antimicrobial Sunflower width to 8 mm above the fermentation broth at 1% concentration can be effective and sustained inhibition of sunflower Sclerotinia sclerotiorum sclerotia formation, so that in 40 d sclerotia were not formed within. The following research will be to strain S-16 as the material, its ability to conduct a preliminary evaluation of biological control, the determination of antibacterial spectrum, the system identification to determine their taxonomic status, and explore the optimal fermentation conditions and the determination of the growth and colonization ability of its antibacterial active substances.By detached leaves, seedling plants, seed treatment and other biometric methods showed that strain S-16 strain of nuclear disks can show effects of different levels of biological control, which in detached leaves and control effect on seedling plants are more than 90%.Determination of the antibacterial spectrum found that strain S-16 on Measured 16 other pathogens have some inhibitory effect.Bacteria by conventional morphological and physiological and biochemical reactions, combined with Biolog identification and 16S rDNA sequence analysis, the strain S-16 was identified as a Bacillus subtilis.Strain S-16 on antifungal preliminary study showed that strain S-16 antimicrobial active substance, there is a volatile material, the strain level and may be the performance of one of the main effects of biological control.The pH, temperature, fermentation conditions and determination of the different culture time, strain S-16 6~7 in the pH value of the weak acid environment of 25℃, 48 h culture to play the best antibacterial effect.