A bacterial isolate from the rhizosphere of potato (Solanum tuberosum L.) identified as Ochrobactrum lupini IPA7.2

We present the results of molecular, genetic, physiological and biochemical investigations of a bacterial isolate from the rhizosphere of potato ( Solanum tuberosum L.) as an object to study plant-microbial associativity, used in particular to improve the existing technologies for the production of high-quality planting material by the method of plant culture micropropagation in vitro. To correctly identify the isolate at the species level, we took into account the results of analysis of the current status of prokaryote identification and systematics, reflected in a number of recent reviews. Phylogenetic constructs with strains of the genera Ochrobactrum, Brucella, Ensifer, Mesorhizobium, Rhizobium, and more (closely related to the isolate under study), which were generated by using DNA sequences of 16S rRNA genes, revealed the isolate in the immediate surroundings of members of the genus Ochrobactrum. The isolate turned out to be part of the taxonomic group Ochrobactrum anthropi - one of the 1912 taxonomic groups recorded to date, which comprise 6193 prokaryotic species and each include species with coinciding (or almost coinciding) sequences of 16S rRNA genes (http://www.ezbiocloud.net/identify). In accordance with the conceptual propositions formulated in the above-mentioned publications, the species differences within these groups are determined at the level of other molecular genetic (and biochemical and physiological) properties and, with a high probability, by horizontal gene transfer. With account taken of the resulting set of elements of the polyphasic approach, the strain isolated by us was found to be closest to the known type strain O. lupini LUP21, which is capable of reinfecting leguminous plants of the genus Lupinus and which carries nodulation and nitrogen fixation genes ( nodD and nifH ), transferred horizontally into it from rhizobial species. This gave us grounds to identify the isolate being examined as Ochrobactrum lupini IPA7.2.