Phosphate solubilizing microorganisms (PSMs) in soil have been shown to reduce mineral phosphate fertilizer supplementation and promote plant growth. Nevertheless, only several P-solubilizing microorganisms capable of solubilizing both organic and mineral sources of soil phosphorus have been identified up to now. The aim of this study was to evaluate the inorganic soil phosphate solubilizing activity of phytate-hydrolyzing Pantoea brenneri soil isolates. We showed that the strains efficiently solubilize a variety of inorganic phosphates. We optimized the media composition and culturing conditions to improve the solubilization efficiency of the strains and investigated the mechanisms of their phosphate solubilization. Through HPLC analysis, it was determined that P. brenneri produce oxalic, malic, formic, malonic, lactic, maleic, acetic, and citric acids as well as acid and alkaline phosphatases while growing on insoluble phosphate sources. Finally, we analyzed the influence of P. brenneri strains with multiple PGP-treats on plant growth in greenhouse experiments and showed their ability to promote growth of potato.

The objective of this study was to screen Kazakhstan-developed potato varieties for DNA markers linked to genes conferring extreme resistance to potato virus Y (PVY) and to evaluate their resistance to PVY infection. The object of the study was the biomaterial from 36 potato varieties provided by Kazakh Scientific Research Institute of Fruit and Vegetable Growing Limited Liability Partnership and Kostanay Scientific Research Institute of Agriculture Limited Liability Partnership. To determine the level of resistance to potato virus Y in the samples, plants were artificially infected with the virus in open ground and under controlled phytotron conditions. The assessment was carried out by visual observation of symptoms on inoculated potato plants, as by enzyme-linked immunosorbent assay. 38% of the varieties have shown extreme resistance to potato virus Y, 16% - Medium resistance (MR), 8% - Susceptible (S) and 41 % - High sensitivity (HS). The results obtained can be used in breeding programs to create virus-resistant potato varieties, as well as in fundamental research on the mechanisms of potato resistance to potato virus Y.