Identification Of Species And Effect Of Six Rhizosphere Microorganisms Involved In Peach Replant Diseases

At present, with the development of peach industry and regularization of production, replant disease of peach is more severe. The six rhizosphere microorganisms was studied on its classification and interaction in this paper to provide the theory for the mechanisms and the biological of replant disease. Three rhizosphere bacteria strains (CN-X4, CN-X9, CN-X17) and three rhizosphere actinomyces strains (CN-G2, CN-G3, CN-G5) were identified by 16S rDNA sequences and biological characteristics. The three bacteria strains could utilize amygdalin as carbon source and produce hydrocyanic acid and the three rhizosphere actinomyces strains show different antagonism effect to the three bacteria strains by plate bacteriostasis assays. Pot trials were designed to monitor the effect of the bacteria strains and the actinomyces strains. The result showed that strain CN-X4 and strain CN-X17 were identified as Agrobacterium tumefaciens, but they were different subspecies. Strains CN-X9, CN-G2 and CN-G5 were proved to belong to Pseudomonas sp, Streptomyces microflavus, Streptomyces lavendulae respectively, Strain CN-G3 may be close or similar to a species of Streptomyces griseus; The peach trees were forwarded to grow by three rhizosphere bacteria strains or by six rhizosphere microorganisms in sterilization oil. The biocontrol effect is significant in pot trials and the treatment of strain CN-G5 is best in all. The unbalance of the rhizosphere microorgznisms is considered as a crucial factor for peach replant diseases occurring.