A BACTERIAL ISOLATE FROM THE RHIZOSPHERE OF POTATO (Solanum tuberosum L.) IDENTIFIED AS Ochrobactrum lupini IPA7.2

Abstract

The authors declare no conflict of interests Acknowledgements: We thank S.N. Dedysh for assistance in molecular genetic analysis and Yu.M. Serekbaeva for her help in 16S rRNA gene sequencing. We are also sincerely grateful to Prof. Dr Frank Oliver Glöckner for his valuable comments on the use of the resource https://www.arb-silva.de. Immunofluorescence microscopy was performed at the Symbiosis Center for collective use of scientific equipment (Institute of Biochemistry and Physiology of Plants and Microorganisms RAS, Saratov). DNA preparation, sequencing and assembly of the fragments were made in the Laboratory of microbiology of wetland ecosystems (Institute of Microbiology RAS, Moscow) and ZAO «Evrogen» (Moscow). Received November 14, 2016 A b s t r a c tWe 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.

Improving the efficacy of potato clonal micropropagation by inoculation with the rhizosphere bacteria <i>Azospirillum baldaniorum</i> Sp245 and <i>Ochrobactrum cytisi</i> IPA7.2

“…Our data show that this strain has a high ability to produce the plant hormone indole-3-acetic acid, which explains its promotion of the growth of microplant roots (Kargapolova et al, 2020). O. cytisi IPA7.2, which we isolated directly from potato roots and which is native to the soils of Saratov Region, is more resistant to stress than Azospirillum (Burygin et al, 2017(Burygin et al, , 2019. This strain withstands large fluctuations in temperature and high salt and herbicide, which explains its ability to protect plants from stress, including osmotic stress (Evseeva et al, 2019).…”

“…Inoculation of microcuttings. We used two rhizospheric bacterial strains -A. baldaniorum Sp245 (Baldani et al, 1983) and O. cytisi IPA7.2 (Burygin et al, 2017(Burygin et al, , 2019. Both strains were from the IBPPM RAS Collection of Rhizosphere Microorganisms (Saratov; http://collection.ibppm.ru/).…”

Rhizobacteria Inoculation Effects on Phytohormone Status of Potato Microclones Cultivated In Vitro under Osmotic Stress

“…Ochrobactrum cytisi IPA7.2 (IBPPM 544, RCAM04481) is a natural potato associate isolated from the rhizosphere of potato cv. Nevsky [ 24 ]. O. cytisi IPA7.2 promotes potato growth and is promising for association with plants.…”