Isolation And Identification Of Antagonistic Fungus Against Ginger Bacterial Wilt And Investment On The Antagonistic Mechanism

In this research, pathogenic bacteria were isolated from the soils of ginger bacterial wilt areas in Jiang Yong, Hunan Province with the method of dilution plating procedure. Strain H1that classified to Pantoea agglomerans and strain Gl that classified to Ralstoniu spp. were identified as the pathogenic bacterium in Jiang Yong by integrating the analysis of the identification of etiological pathogenicity, morphological observation and molecular identification.The result of etiological pathogenicity showed that the strain G1had a more serious pathogenicity than strain H1. So Ralstonia was identified as the main pathogenic bacteria-marked strain G1in this research.Ten inhibitory strains were isolated from the rhizosphere microorganism by the method of planting antagonistic experiment of the two pathogenic bacterium:strainH1and strain G1.The ten isolated strains were identified as Trichoderma. Strain23had the largest antagonism.The result of morphological observation showed that the mycelium of strain23were white and the spores which shaped globular obovate were green.The result of molecular identification showed that its ITS sequence had a99%similarity to Trichoderma hamatum. The antagonistic strain23did not require a very demanding living environment.It was able to live in a high-temperature but low-alkaline environment as well as under high light intensity.It was suit for a antagonistic strain in agricultural production.In order to explore the mechanism of the antagonistic effects of antagonistic strain, this paper analysed the antagonistic chemical compositions of the metabolist fluid as well as the impact of temperature, acidity and basicity and appearance time by researching of the strain antagonism and the metabolist fluid antagonism. The result of this research showed that the antagonistic substance in this experiment was protein.The metabolic liquid environment in48h was the most suitable role environment.pH was acidic. When the saturation of ammonium sulfate reached50%, it will be sedimented.The comprehensive experiment results showed that the structural substance that can restrain the growth of pathogenic bacterium which produced by antagonistic strains is protein, that has a molecular weight of72kD.