Molecular analysis of the diversity of nitrifying bacteria in the soils of the forest and steppe zones of European Russia

Nitrifying bacteria play a key role in the global nitrogen cycle due to their ability to convert reduced nitrogen compounds (ammonium) to oxidized ones (nitrite and nitrate). Recent investigations based on the methods of molecular ecology revealed that bacteria are responsible for nitrification in natural ecosystems. At the same time, data on the species composition of the nitrifiers in soil microbial communities are scarce. Soil samples collected in the forest and steppe areas of European Russia and the enrichment cultures of nitrifying bacteria isolated from these samples were used for molecular studies of the diversity of the amoA gene encoding the synthesis of the key enzyme of autotrophic ammonium oxidation. The nitrifying bacteria of the genera Nitrosospira and Nitrosovibrio were found in all the studied soils from natural biocenoses and agrocenoses.