The homology analysis of internal transcribed spacer sequence of ribosomal DNA in common dermatophytes

In order to analyze the sequences of the internal transcribed spacer (ITS) including the 5.8 S ribosomal DNA (rDNA) of common dermatophytes, so as to obtain a rapid and accurate method to identify the species of dermatophytes and to establish the phylogenetic tree of these species to understand their relationship,16 strains of dermatophytes were collected and preliminarily identified by morphological characteristics. General primers for fungi ITS1 and ITS4 were used to amplify the ITS rDNA of each strains with PCR. The PCR products after purification were sequenced directly and were analyzed through internet. In the results,11 strains were identified by means of morphological features, among which 5 strains were Trichophyton,5 strains were Microsporum and 1 was Epidermaphyton, which was consistent with the results by molecular biology. In the 5 unidentifiable strains, 1 strain was proved to be Chrysosporium by molecular biology. These strains studied could be divided into 3 different classes as indicated in the analysis of the phylogenetic tree of the sequences in ITS, which were quite different from those of morphological classification. It is evident from the above observations that the molecular method of analysis on the ITS sequences is a rapid, highly sensitive and accurate approach for the detection of dematophyte species, however, it still exhibits some limitations needing the supplementation with morphological identification.

Seasonal and Tissue Age Influences on Endophytic Fungi of Pinus tabulaeformis (Pinaceae) in the Dongling Mountains, Beijing

Endophytic fungi associated with Pinus tabulaeformis Carr. were investigated in the Dongling Mountains of Beijing. A total of 16200 tissue segments of P. tabulaeformis from four sample collections were processed, and 10659 fungal isolates were recovered. The overall colonization and isolation rates of endophytic fungi from high to low were spring〉winter〉autumn〉summer and in different tissues were bark〉needle〉xylem, irrespective of sampling seasons. The colonization rates of endophytic fungi of needles increased with age in the four sample collections. There were no significant differences of the colonization rates of endophytic fungi among 1-, 2-, and 3-year-old bark and xylem, except for significantly lower colonization rates in 1-year-old bark than in 2- and 3-year-old bark in summer. A similar trend of the isolation rates of endophytic fungi occurred. A total of 24 fungal taxa were recorded, of these five taxa Alternaria alternata, Leptostroma sp., Pestalotiopsis besseyi, Phoma lingam, and Phomopsis archeri, were consistently isolated as the common fungi in each sample collection. Our results suggest that some fungi show a certain degree of tissue recurrence or specificity, and the composition of endophytic assemblages is not conspicuously influenced by the seasonal factor.

Research Progress on Artificial Cultivation of Trhicoloma Matsutake and Theory of the Shiro in Changbai Mountains

Study on artificial cultivation of Tricholoma matsutake carried through by the present research group in Changbai Mountains in recent years was briefly reviewed in the paper, and then, the signify-cance of cultivation, mechanism of formation, hiberar-chy, growth cycle and suitable living environment, were summarized.