| The Republic of Tajikistan is a inland and alpine country, which has a complex ecosystem with a unique, rich biodiversity and numerous rare species, and has important research and development value. In this paper, pure culture, 16 S rDNA PCR-RFLP analysis, Rep-PCR, sequencing and phylogenetic analysis of 16 S rDNA,transparent ring hydrolytic method, DNS method, Folin- phenol reagent method and agar block method were adopted for the first time to analyze the community structure and population diversity of the soil culturable bacteria and actinomycetes and screen strains which had functional enzyme and antagonistic activity. The study aimed at clearing the diversity and distribution of microbial populations in different ecological environments and enriched the repository of microbial species and gene banks, as well as soil microbial new resources mining and the development of new active substances to lay the scientific foundation. The major findings were as follows:1. 110 bacterial strains were isolated from the farmland, natural grassland, woodland and desert soil.They were Firmicutes(80.9%), Proteobacteria(17.2%) and Actinobacteria(1.85%) and belong to Bacillus,Stenotrophomonas, Brevibacterium, Arthrobacter, Clavibacter, Brevundimonas, Variovorax, Pseudomonas,Sporosarcina, Lysinibacillus, Achromobacter and Rheinheimera.The Bacillus(71.8%) was the absolutely dominant population including 63 isolates and Rep-PCR gene polymorphisms p-resented 17 different fingerprints. The population distribution,composition and diversity of soil culturable bacteria were significantly different and closely related to the soil environment. Shannon di-versity index, Simpson dominance and Pielou index were significantly positively correlated(p<0.05)with soil organic matter, total and available nitrogen and water content.Soil potassium content also significantly affected the bacterial Shannon diversity and Simpson dominance.2. 53 actinomycetes were isolated from farmland,natural grassland, woodland and desert soil in Tajikistan,and were attributed to the genus of Streptomyces, Nocardiopsis, Arthrobacter, Nocardia,Actinomyces, and Actinomycetales bacterium. Streptomyces was dominant populations; Nocardiopsis,Actinomycetales bacterium, Nocardia was the second dominant populations; while Actinomyces,Arthrobacter which each contain only one strain belong to rare populations. The diversity index of soil culturable actinomycetes showed that Simpson dominance index was 0.87; Shannon-Wiener diversity index was 2.6 and Pielou evenness index was 0.82.3. 110 strains bacteria which contained 70 strains producing amylase, 56 strains producing protease,37 strains producing cellulase, 16 strains producing lipase were isolated from the soil. The highest producing amylase enzyme strain was T-17 which belonged to Bacillus malacitensis, and the enzyme activity was 18.067 U / mL; H2-2 was the highest producing protease strain and the enzyme activity was411.43 U / mL. Coarse enzymology properties determination of T-17 strain for producing high amylase activity showed that the amylase had the characteristics of high temperature, neutral, salt tolerance, the optimal catalytic temperature was 70 ℃, and still had higher enzyme activity at 30~70℃. the optimal catalytic pH was 7.0, a relatively stable in pH 6.0 ~ 8.0. having stronger salt-tolerant characteristics,concentration of NaCl in 4 mol·L- 1 could still keep high enzyme activity. Ca2+ and K+ had apparent activation to the enzyme. The strain of T-17 was identified as Bacillus malacitensis through morphological observation and molecular method.4. Among them, 13 strains had antagonistic effect on the Fusarium oxysporum f. sp. pathogen;11 strains had antagonistic effect on Rhizoctonia solani pathogens; 2 strains had antagonistic effect on Verticillium dahliae Kleb and Aspergillus niger; 7 strains had antagonistic effect on Alternaria solani pathogenic; 5 strains had antagonistic effect on Penicillium digitatum; 9 strains had antagonistic effect on Magnaporthe oryzae; 28 strains had inhibited effect on Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923; 36 strains had antagonistic effect on Bacillus subtilis ATCC6633; 10 strains had antagonistic effect on the northern Pseudomonas fulva SW32. |
