| In this paper , we took tremella as research object around GuTian ,Fujian province. We used the T-RFLP technology as the main method , combinning the traditional method of plate culture.The results revealed phenotypic polymorphism and genetic diversity of mycelial infected fungus comprehensively and systematicaly, providing a scientific basis for the integrated control of mycelial disease.For T-RFLP, the study used the method of proteinase K-CTAB- liquid nitrogen freeze-thaw extraction to extract the total DNA, and the total DNA were used for PCR amplification. Using the 16S rDNA of bacteria and the ITS sequences of fungus as target genes, we got the target band. PCR products were digested by HaeⅢand MspI.T-RFs were processed by GeneMarker software.We identified 37 species of bacteria by the RDP database comparation , and also proved the existence of fungi. According to the results of the T-RFs analyzing and comparation,we could be considered that there were complex microbial systems which included the bacteria and fungi as main communities. T-RFLP could provide us more comprehensive information on the composition of microbial flora , but the taxonomic status and functional information of species were restrainted by the storage capacity. The results of this study showed that for the study object of this article, T -RFLP was a more powerful tool that provided a large number of information on non-dominant bacteria.So it could provide the theoretical and practical basis for the identification and screening of mycelial pathogen associated microbiology.This paper used the traditional plate culture method to separate and purificate the pathogenic fungus, getting a total of 22 species by cloning and sequencing.We researched for their biological characteristics. The study of biological characteristics included the observation and comparison of the morphological characteristics of the colony characteristics, mycelial morphology and the methods of conidiophore grow. We compared the appropriate living conditions of different strains, including the effect of temperature, pH to the growth of mycelium. The results showed that: there were 6 types of colony morphology of the test strains, The difference of colony color and conidiophore was big. There was a little difference in the optimum growth temperature of each strains, the optimum growth temperature was between 25 and 35℃, the difference of the optimum pH was between 5and 6.ITS sequencing was also used for distincting the species of those strains. ITS sequencing results showed that the first group of the strains was neurospora sitophila,containing 5 stains; typeⅡstrains was cunninghamella elegans lendn, containing 2 stains; typeⅢstrains was trichoderma, containing 7 stains; typeⅣstrains was trichoderma, containing 3 stains; typeⅤstrains was penicillium, containing 3 stains; typeⅥstrains was aspergillus, containing 2 stains.However,the homology of ITS sequences of typeⅢstrains and typeⅣstrains was 98%,these two groups could be determined as different subspecies of one specie.This is the first time to use the T-RFLP technique in the fungus microbial diversity research, making a quick identification to the species of microbial community in the susceptible mycelial. We provides a new approach on the research of mycelial diseases and fungus diseases. And we found out a new mold - Cunninghamella elegans Lendn in the susceptible tremella, making a major breakthrough in the research of mycelial cultivation related pathogen diversity.
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