Influence of Rhodococcus qingshengii VKM Ac-2784D biostimulator on bacterial isolates from potato endo- and rhizosphere

The potato microbiome has a significant impact on plant growth and development. In order to affect this microbiome, agriculture can use various biopreparations on the basis of soil microorganisms. Being vulnerable to pathogens and drought, potato plants are particularly useful in the development of biopreparations. Special attention is given to Rhodococcus bacteria due to their ability to clean contaminated soil and stimulate plant growth. The present study was aimed at examining the effect of Rhodococcus qingshengii VKM Ac-2784D on bacteria isolated from potato endo- and rhizosphere. It is known that only a small fraction of microorganisms within the plant microbiome can be obtained in pure culture. Given these limitations, it was possible to isolate over 70 endophytic strains without the use of selective media and show that many of them are sensitive to the presence of a biopreparation component on the basis of Rhodococcus qingshengii VKM Ac-2784D. The metagenomic study indicates a change in the composition of the microbial community following treatment with the biopreparation. The experiments also show that the bacteria remain sensitive to Rhodococcus even in the presence of other competing strains. In general, the study results indicate a modulating effect of the biopreparation on the potato microbiome without phytotoxicity. The findings are important for understanding the effect of the biopreparation on the microbial composition of soil and potato plants, as well as for developing effective strategies for the use of microorganisms in agriculture.

Rhodococcus, inoculation, secondary metabolites, endophytes, potato