Isolation and characterization of the antagonistic actinomycete 3-2 of rice blast disease as well as the preliminary study of its active products
[Objective]This study aims to screen effective biocontrol strains against Magnaporthe oryzae so as to provide a basis for biological control of this disease.[Method]The agar plate dual culture was used for initial screening and the fermentation filtrate-amended medium method for re-screening of actinomycetes strains with good inhibitory effect on Magnaporthe oryzae,and the culture characteristics,colony morphology,as well as physiological and biochemical properties of the strains were observed,and then a phylogenetic tree was constructed based on the 16S rDNA sequences of the strains,so as to identify the taxonomic status of the strains.In addition,this study determined the effects of conditions such as temperature and UV irradiation on the antibacterial activity of the fermentation broth of the strain 3-2,and so accomplished the determination of the antifungal spectrum of the strain 3-2.[Result]The indoor bioassay test showed that the 5-fold aseptic fermentation broth of the strain 3-2 inhibited the mycelial growth of Magnaporthe oryzae as high as 98.41%.The strain was identified as Streptomyces cellostaticus.The active substances in the fermentation broth were sensitive to UV irradiation but thermally stable.The strain 3-2 was more effective in inhibiting Nigrospora oryzae and Sclerotinia sclerotiorum,with the inhibition rate reaching 90.01%and 81.50%,respectively.[Conclusion]The strain 3-2 has a strong inhibitory effect on Magnaporthe oryzae,which can provide references for the research and development of blast biocontrol agents.
万方数据
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