Abstract: The republic of Tajikistan,located in Southeast Central Asian and next to Xinjiang,China on the east, is an inland alpine country. The harsh natural climate has produced a variety of complex ecosystems,and possessed unique rich biodiversity. In recent years,the effects of human activities greatly changed the ecological environment in Central Asia region,leading to a degradation growth of vegetation. The soil degradation and desertification made biodiversity strongly interfered in some areas. By using the technique of culture-dependent,amplified ribosomal DNA restriction fragment analysis(16S rDNA PCR-RFLP),Rep-PCR,16S rDNA sequencing and phylogenetic analysis,this paper firstly surveyed the soil microbial resources situation in Tajikistan to study the community structure and population diversity of soil culture bacteria in Hartlon,Tajikistan. One hundred and ten stains were isolated from farmland,natural grassland,forestland and desert in Hartlon. Using four restriction enzymes Hae Ⅲ,HinfⅠ,MspⅠ and HhaⅠto digest 16S rDNA gene to analyze the Enzyme fingerprinting,results showed that the 110 stains clustered into 23 OTUS(Operational Taxonomic Units). Phylogenetic analysis revealed that 110 stains soil cultivable bacteria in Hartlon could be distributed into three sorts: Firmicutes (80.9%),Proteobacteria(17.2%)and Actinobacteria(1.85%),which belonged to 12 genus—Bacillus,stenotrophomonas, Brevibacterium,Arthrobacter,Clavibacter,Brevundimonas,Variovorax,Lysinibacillus,Sporosarcina, Pseudomonas,Achromobacter,and Rheinheimera. Therein,Bacillus which accounted for 71.8% was the dominate population in cultivable bacteria,followed by Pseudomonas which accounted for 10.9%. The Rep-PCR ge-nomic fingerprinting analysis of Bacillus showed that there were 17 different poly-morphism fingerprints in 63 strains and had richer diversity. Population distribution and structural composition of soil cultivable bacteria had obvious differences in different sample plots. The species diversity trend showed: natural forestland > natural grassland > farmland > desert,and natural grassland had the highest Shannon Index(2.538),Simpson Dominance Index(0.890)and Pielou Evenness Index(0.906);In farmland,cherry and cotton intercropping had the highest soil bacteria Shannon Index(1.619),Simpson Dominance Index(0.751)and Pielou Evenness Index(0.676). Correlation analysis showed that,the soil physical and chemical properties were closely related to the cultivable bacteria; soil organic matter,total nitrogen,available phosphorus,available potassium and moisture content were the key physical and chemical factors that affected the diversity index significantly(P<0.05). This research not only studied the community structure and species diversity of soil cultivable bacteria in Tajikistan,analyzed its soil microbial properties,but also enriched microbial species and gene library. It laid the foundation to promote the protection of microbial resources,also provided scientific basis for studying the influence of microbiology and functional diversity on environmental changes,and monitoring early warning of soil health quality.

Key words: Tajikistan, culture-dependent, 16S rDNA, RFLP, Rep-PCR