LOW TEMPERATURE AND VEGETATION EFFECTS ON THE SOIL BACTERIAL COMMUNITIES STRUCTURE IN HIGH MOUNTAINOUS AND COLD BIOTOPES IN KYRGYZSTAN

It is well known that soil microorganisms play essential roles in the biogeochemical cycling of biogenic elements and soil-forming processes. However, little is known about the effect of the vegetation type on the bacterial community structures in soils from cold regions. For these reasons, we have analysed the bacterial communities of eight biotopes covered with different plants and two biotopes without vegetation in the Son-Kull Valley as the coldest corner in Kyrgyzstan. Using the culture-depended and culture-independent (16S rRNA gene sequencing) methods, we found 4 phylum (Actinobacteria-55.0, Proteobacteria- 30, Firmicutes- 13, and Bacteroides-2) and 5 classes of the bacterial community, with dominant classes of Actinomycetia (60.03), Gammaproteobacteria (25.0), Bacilli (10.0), Bacteroidia (3.0) and Alphaproteobacteria (2.0). The dominant generalist genera were Arthrobacter, Pseudomonas, Actinobacter, Dermacoccus, Brevibacterium, and Micrococcus. The results have confirmed that bacterial community structures were significantly affected by the vegetation type and environment factor, such as temperature. The diversity of the bacterial community was higher in the rhizosphere of succulent vegetation with a short lifespan, that is, in ephemerals, and with a high content of organic matter, like manure, in soil. The soil under the snow harboured the highest proportion of uncultured bacteria, representing Actinobacteria phylum.

Keyword: environmentfactor; soil-forming bacteria; 16S rRNA gene ofbacterial diversity; dominant soil bacterial phylotypes and classes