The Quality and Productivity of Strawberry (Fragaria × ananassa Duch.) Improved by the Inoculation of PGPR Bacillus velezensis BS89 in Field Experiments

Efficient plant-growth-promoting rhizobacteria (PGPR) used as biofertilizers and biological control agents are promising substitutes for minimizing the application of synthetic agrochemicals in crop production. We studied the effect of PGPR strain Bacillus velezensis BS89 alone and in combination with three forms of nitrogen fertilizers (ammonium nitrate, carbamide, and ammonium sulfate) on the productivity of two strawberry varieties in three-year field experiments. We first showed that the application of PGPR Bacillus velezensis BS89 on strawberries demonstrated the same effect as the application of nitrogen fertilizers. Use of the strain BS89 increased the chlorophyll content in plant leaves by 2.7–6.8%, and also increased the yield of berries by 6.7–36.4% for cv. Rusich and 7.5–19.3% for cv. Troitskaya depending on the form of nitrogen fertilizer. The best results in the yield of strawberry plants of the cv. Rusich were achieved in the variant BS89 + ammonium nitrate (41.9–57.4%), and the cv. Troitskaya—in the BS89 + carbamide variant (8.1–38.8%). Three-year use of strain BS89 for cv. Rusich resulted in an increase of runner’s weight by 212.1%, and also the weight of the roots by 120%, thereby significantly improving the mineral nutrition of plants. This is mainly associated with the plant growth-promoting activity of Bacillus velezensis BS89, which was able to produce a high amount of IAA—494.1 µg/mL. We believe that the PGPR strain BS89 can be successfully used for growing strawberries. However, each variety requires careful selection of the composition of nitrogen fertilizers and analysis of the compatibility of fertilizers and the PGPR strain

Plant Development of Early-Maturing Spring Wheat (Triticum aestivum L.) under Inoculation with Bacillus sp. V2026

The effect of a plant growth-promoting bacterium (PGPB) Bacillus sp. V2026, a producer of indolyl-3-acetic acid (IAA) and gibberellic acid (GA), on the ontogenesis and productivity of four genotypes of early-maturing spring wheat was studied under controlled conditions. The inoculation of wheat plants with Bacillus sp. V2026 increased the levels of endogenous IAA and GA in wheat of all genotypes and the level of trans-Zeatin in Sonora 64 and Leningradskaya rannyaya cvs but decreased it in AFI177 and AFI91 ultra-early lines. Interactions between the factors “genotype” and “inoculation” were significant for IAA, GA, and trans-Zeatin concentrations in wheat shoots and roots. The inoculation increased the levels of chlorophylls and carotenoids and reduced lipid peroxidation in leaves of all genotypes. The inoculation resulted in a significant increase in grain yield (by 33–62%), a reduction in the time for passing the stages of ontogenesis (by 2–3 days), and an increase in the content of macro- and microelements and protein in the grain. Early-maturing wheat genotypes showed a different response to inoculation with the bacterium Bacillus sp. V2026. Cv. Leningradskaya rannyaya was most responsive to inoculation with Bacillus sp. V2026

Endophytes from Halotolerant Plants Aimed to Overcome Salinity and Draught

The aim of our research was to study the endosphere of four halophytic plants: Salicornia europaea L., Salsola australis (R.Br.), Bassia sedoides (Pall.) and Kochia prostrata (L.) Schrad. from arid and saline areas of the Stavropol Territory, Russia. In total, 28 endophyte strains were isolated from the roots and stems of these halophytic plants. Most of the isolates (23 out of 28) were identified as Bacillus sp. while others belonged to the genera Oceanobacillus, Paenibacillus, Pantoea, Alcaligenes and Myroides. Three strains of Bacillus sp. (Se5R, Se1-1R, and Se1-3S), isolated from the S. europaea were capable of growth at 55 °C and in 10% of NaCl. Strains Se1-4S, Kp20-2S, and Bs11-2S Bacillus sp. (isolated from the S. australis, K. prostrata and B. sedoides, respectively) demonstrated strong plant growth promoting activity: 85–265% over control lettuce plants and a high degree of growth suppression (59.1–81.2%) of pathogenic fungi Fusarium oxysporum, Bipolaris sorokiniana and Rhizoctonia solani. Selected strains can be promising candidates for the development of bioinoculants to facilitate salt soil phytoremediation and be beneficial for mitigating the salt stress to the plants growing in salt-affected habitats

Bosea vaviloviae sp. nov., a new species of slow-growing rhizobia isolated from nodules of the relict species Vavilovia formosa (Stev.) Fed.

The Gram-negative, rod-shaped slow-growing strains Vaf-17, Vaf-18(T) and Vaf-43 were isolated from the nodules of Vavilovia formosa plants growing in the hard-to-reach mountainous region of the North Ossetian State Natural Reserve (north Caucasus, Russian Federation). The sequencing of 16S rDNA (rrs), ITS region and five housekeeping genes (atpD, dnaK, recA, gyrB and rpoB) showed that the isolated strains were most closely related to the species Bosea lathyri (class Alphaproteobacteria, family Bradyrhizobiaceae) which was described for isolates from root nodules of Lathyrus latifolius. However the sequence similarity between the isolated strains and the type strain B. lathyri LMG 26379(T) for the ITS region was 90 % and for the housekeeping genes it was ranged from 92 to 95 %. All phylogenetic trees, except for the rrs-dendrogram showed that the isolates from V. formosa formed well-separated clusters within the Bosea group. Differences in phenotypic properties of the B. lathyri type strain and the isolates from V. formosa were studied using the microassay system GENIII MicroPlate BioLog. Whole-cell fatty acid analysis showed that the strains Vaf-17, Vaf-18(T) and Vaf-43 had notable amounts of C-16:0 (4.8-6.0 %), C-16:0 3-OH (6.4-6.6 %), C-16:1 omega 5c (8.8-9.0 %), C-17:0 cyclo (13.5-13.9 %), C-18:1 omega 7c (43.4-45.4 %), C-19:0 cyclo omega 8c (10.5-12.6 %) and Summed Feature (SF) 3 (6.4-8.0 %). The DNA-DNA relatedness between the strains Vaf-18(T) and B. lathyri LMG 26379(T) was 24.0 %. On the basis of genotypic and phenotypic analysis a new species Bosea vaviloviae sp. nov. (type strain RCAM 02129(T) = LMG 28367(T) = Vaf-18(T)) is proposed