Screening Research Of Antagonism Actinomyces Which Isolated From Saline-alkali Soil In Hexi Corridor On Four Plant Pathogenic Fungi

50strains of actinomycetes were isolated from the saline-alkali soils of HexiCorridor in Gansu Province which were used as experiment ones on resistanceresearch.The main results are as follows:1.Oxford cup method and Pair culture method were used to screen antagonisticbacteria. The results of antagonism activity showed that4strains have the antibaterialproperty to three different bacteria.Ⅰ22-5-1has antagonism to E.coli, Ⅰ22-5-3hasantagonism to Bacillus subtitles, Ⅳ16-3-1,Ⅹ8-5-2both have antagonism to S.aureus.In which Ⅰ22-5-3and Ⅳ16-3-1have higher antagonism diameters ofinhibiting bacteria circle were both beyond15mm.There are6strains have the antibaterial property to four different fungus.Ⅰ18-5-2has antagonism to Rhizoctoniz solani and Botrytis cinerea, Ⅲ22-3-3hasantagonism to Botrytis cinerea, Ⅲ22-3-12has antagonism to Rhizoctoniz solani andAlternaria solani, Ⅲ23-4-3has antagonism to Botrytis cinerea, Ⅳ16-3-2,DC009-1-23both have antagonism to all four different fungus. In which Ⅲ22-3-12has a higherantagonism diameter to Alternaria solani, Ⅲ23-4-3has a higher antagonism diameterto Botrytis cinerea,Ⅳ16-3-2has higher antagonism diameters to Rhizoctoniz solani,Alternaria solani and Botrytis cinerea, DC009-1-23has a higher antagonism diameterto Rhizoctoniz solani, Alternaria solani and Fusarium verticillioides. The inhibitingbacteria circle were all beyond15mm.2.Growth rate method was used to rescreen the strains which have higher antagonismdiameter(beyond15mm).The result showed:The mycelial growth of DC009-1-23toRhizoctoniz solani, Alternaria solani and Fusarium verticillioides, Ⅲ23-4-3toBotrytis cinerea, Ⅲ22-3-12to Alternaria solani, Ⅳ16-3-2to Rhizoctoniz solani,Botrytis cinerea are all beyond80%. the inhibition effect of DC009-1-23to Alternariasolani was up to88.88%.3.In order to increase the production of the fungicidal substance,the liquid mediacompositiom was optimized and the fermentation condition was primarily studied.Theoptimum fermentation medium of the Ⅳ16-3-2Strain was composed of millet10g, soluble starch10g,NaCl2g,peptone3g, CaCO32g.The optimum fermentation conditionwas the initial pH of medium6.5,fermentation temperature28℃, shaking speed160r／min,liquide volume60mL(in250mL flask).4.Tissue culture method was used to determine the antagonistic efficacy ofⅣ16-3-2,DC009-1-23to Rhizoctoniz solani and Ⅲ22-3-12,Ⅳ16-3-2,DC009-1-23toAlternaria solani.Biopsy tests showed,the control effects of Ⅳ16-3-2to Rhizoctoniasolani and Ⅲ22-3-12,Ⅳ16-3-2,DC009-1-23to Alternaria solani reached beyond50%.5.Morphological characteristic and phylogenetic analysis based on16S rRNA genesequence supported the strain Ⅳ16-3-2to be Streptomyces variabilis,and the strainDC009-1-23to be Streptomyces lilaceus. Morphological characteristic supportedstrains Ⅰ18-5-2,Ⅳ22-3-3和Ⅳ22-3-12to be Streptomyces,and strain Ⅲ23-4-3to beNocardiopsis.