Microbial Diversity Of Tricholoma Matsutake Growth Soils In Yajiang, Sichuan, China

Eight soil samples were collected from Yajiang County, where is the growth area of Tricholoma matsutake in the southwestern plateau in Sichuan province, the soil microbial biomass C and N, and phosphatase, urease, catalase activity, the amount of soil bacterium, fungus, and actinomycetes was determined. Using BOXAIR-PCR,16S rDNA PCR-RFLP and 16S rDNA sequencing, the genetic diversity and phylogeny of 40 bacterial isolates were analyzed. Furthermore, PCR-DGGE technique was employed to evaluate the soil microbial molecular aspects. The resuts showed as follows:1. The microbial biomass C of tested soils ranged from 132.07 to 371.95 mg·kg-1 and the microbial biomass N ranged from 14.15 to 53.88 mg·kg-1.2. The acid phosphatase activities of tested soils ranged from 0.0938mg·g-1·h-1 to 0.3052 mg·g-1·h-1, the urease activities ranged from 0.0586 mg·g-1·h-1 to 0.2252 mg·g-1·h-1, and the catalase activities ranged from 0.0229 mg·g-1·h-1 to 0.0355 mg·g-1·h-1. The enzyme activity decreased obviously along with soil layer depth increasing.3. The number of bacteria ranged from 3.13×105 to 3.76×107 cfu·g-1, that of actinomycetes ranged from 0 to 3.00×106 cfu·g-1, and that fungi ranged from 4.6×104 to 1.40×106 cfu·g-1 in the tested soil, respectively.40 bacterial strains were isolated and purified, Gram staining and microscopic observation revealed that 19 strains were G+, the other 21 strains were G-.4. BOXAIR-PCR analysis indicated the tested strains were clustered into 6 geno-groups at the similarity of 74%. However, at the level of 65% similarity, these strains were divided into 2 groups (G+and G-), and further formed 7 genotypes at the boundary of 74% similarity by analysis of 16S rDNA PCR-RFLP.5. Eleven stains were selected for 16S rRNA gene sequences analysis based on the results of 16S rDNA PCR-RFLP and BOXAIR-PCR. The phylogenic tree was constructed, the results suggested that these bacteria mainly distributed in the 11 phylogenetic branches. They were genus Bacillus, Lysinibacillus, Paenibacillus, Janibacter, Mycoplana, Collimonas, Variovorax, Stenotrophomonas, Pseudomonas, Psychrobacter, and Pedobacter.6. Total bacterial genomic DNA was extracted for PCR-DGGE profile. The analysis of the profiles showed various types of bacterial communities, which indicated that the soil bacteria were very diversy. The DNA sequences of 10 main bands were analyzed and the most representative bacterium was belonged to actinobacteria, acidobacteria, betaproteobacteria and uncultured bacteria.7. For the Fungal DGGE profile, there were many bands with high brightness, which showed great variation among different sampling points and different soil layers. The DNA sequences of 11 main bands were analyzed and the phylogenic tree was constructed, the results suggested that these fungi mainly distributed in the 8 phylogenetic branches, most of them were belonged to Pezizomycotina.