Plant-microbe associations of the non-traditional sugar plants and the producers of natural sweeteners

Soil microbial succession in chernozem under the influence of rhizodeposites of different groups of plants-sweeteners was investigated. It is found out that non-traditional sugar plants (Helianthus tuberosus, Smallanthus sonchifolius, Cyperus esculentus) enhance mineralization processes and reduce nitrogen immobilization, while producers of sweet glycosides (Stevia rebaudiana, Glycyrrhiza glаbra) do not change the trophic structure of soil microbial society. The species structure of microbial society was studied by the example of a complex of micromycetes. The general trend is decline in fungi species diversity as compared with virgin chernozem. In the root zone of sugar plants a portion of copiotrophic fungi and species of the genus Aspergillus increased. Producers of sweet glycosides stimulated accumulation of toxigenic micromycete species. It is concluded that rhizodeposites cause the increase not only in trophic, but also in «metabolite» interaction of plants with soil microbial society. Accumulation of toxigenic fungi species increases phytotoxic activity of soil that is the reverse «metabolite» impact of microbial society to plants. Indicator species of fungi are suggested to microbial monitoring of chernozem at growing different groups of plants-sweeteners.