Studies On Screening, Identification And Fermentation Conditions Of Actinomycete Antagonistic Against Coniella Diplodiella

For grape white rot disease, this experiment mainly conducted five parts, including the isolation and screening, identification, fermentation optimization, physicochemical property and the extraction of the material.Test results are as follows,1. Seventy actinomycetes strains were isolated from different soil samples by the dilution-plate method. By screening and rescreening,3strains were obtained and they behaved stronger inhibition activities to Coniella diplodiella. Srain G4expressed the best effect, with inhibition zone of26.5mm.The strain G4had inhibited some other pathogenic fungi such as F. graminearum, C. lunata and F. moniliforme and C. diplodiella etc.2. For G4strains, this experiment studied it from these aspects of morphological characteristics, cultural characteristics, physiological and biochemical characteristics, and it showed great similarity with Streptomyces lavendulae. The phylogenetic tree which was builed with16S rDNA sequences analysis showed that the strain G4was very similar with S.lavendulae (AB184415), sharing16S rDNA homology value of100%. Based on the polyphase taxonomical data, strain G4was primarily identified as S. lavendulae.3. The optimal fermentation conditions were determined, which included corn flour6%, glucose5%, soybean powder6%, KNO30.7%, KH2PO40.1%, CaCO30.3%, NaCl0.1%, the strain G4had strongest inhibition activity in the condition of22h seed age,4%inoculation volume (v/v), the medium volume in the flask was50mL/250mL, fermentation period was48hour,200r/min,28℃fermentation temperature and pH was natural.4. Stability, polarity and pH test results of fermentation liquid of strain G4showed that the fermentation liquid under100℃can maintain activity, but can not maintain activity above100℃, it was stable to UV and sunlight and low pH, but not stable on the high pH. By paper chromatography, the active substances has strong polarity, it was weak acidic.5. Based on the physical and chemical properties of fermentation liquid of strains G4, fermentation liquid was pretreated with acetone, ratio of1:1and most of impurities were removed from fermented liquid using column chromatography. Fermentation liquid was changed from liquid into soild using freeze-drying method.