Bradyrhizobium Japonicum Research Articles

Inoculants associated with fertilizers: agronomic increases in bean, soybean and lettuce crops

The objective of the study was to prove the efficiency of inoculation associated with synthetic fertilizers in the agronomic potential of bean, soybean and lettuce. Experiments were carried out in a randomized block design to evaluate the efficiency of inoculation associated with synthetic fertilizers in bean, soybean and lettuce crops. The experimental design used was randomized blocks organized in a factorial scheme, with six replications. In beans, ten treatments were evaluated in four environments. In soybean cultivation, 13 treatments were evaluated in four environments. While in lettuce, six treatments were evaluated in five environments. In each crop, the agronomic and nutritional characteristics were evaluated. Inoculation associated with fertilizers enhances the agronomic and nutritional performance of beans, soybeans and lettuce. Rhodopseudomonas palustris combined with phosphorus and nitrogen fertilization improves bean grain yield. Bradyrhizobium japonicum, Azospirillum brasiliense and Pseudomonas fluorescensare crucial for soybean. Addition of the bacterium Rhodopseudomonas palustris maximized the lettuce biomass.

Fertilizer Management Strategies of Glycine max L. (Soybean) in Northcentral and North-Western North Dakota

Soybean (Glycine max L.) is a new cash crop grown in north central and northwestern North Dakota (ND). Soils and climate in these new soybean areas differ from current fertilizer guidelines. A three-year study to evaluate soybean fertility best management practices was initiated in the spring of 2016 and concluded in 2018. Each year had two sites and twelve treatments. One site was acidic (pH < 6.2) and the other was alkaline (pH > 7.2). Both site treatments were: untreated check, inoculated with rhizobia (Bradyrhizobium japonicum L.), broadcast urea (55 kg ha−1), broadcast MAP (110 kg ha−1), In-furrow 10-34-0 (28 L ha−1), in-furrow 6-24-6 (28 L ha−1), foliar 3-18-18 (28 L ha−1) at V5 and R2, and foliar 3-18-18 (28 L ha−1) with sulfate (1.1 kg ha−1) at V5 and R2. The acidic site had two treatments of sugar beet (Beta vulgaris L.) waste lime (4411 kg ha−1 and 8821 kg ha−1). The alkaline site received treatments of iron ortho-ortho-EDDHA (7.1 L ha−1), and naked ortho-ortho-EDDHA (7.1 L ha−1). An in-furrow treatment of cobalt (2.9 kg cobalt-sulfate ha−1) was added in 2018. Fertilizer treatments did not impact soybean yield, protein content and oil content at the 0.05 significance level.

The influence of metal nanocarboxylates on the nitrogen-fixing activity of symbiotic soybean systems grown under field conditions

Background. Numerous scientific and industrial studies have proven the high effectiveness of using micronutrients in nanoscale form in agricultural crop cultivation technologies. Among them, special attention is drawn to soybeans, which hold a leading position in terms of sown areas among other leguminous crops in the country. They can provide up to 70 % of their own nitrogen needs through the fixation of its molecular form from the atmosphere in symbiosis with Bradyrhizobium japonicum nodulating bacteria. New methods of molecular biology, biotechnology, and genetic engineering, along with classical methods of microbiology, plant physiology, genetics, and agrochemistry, allow for addressing both fundamental questions regarding the characteristics of formation and functioning of legume-rhizobial systems, and practical approaches to correcting the interactions between symbiotic partners with the aim of creating highly effective symbioses. Therefore, research aimed at significant increasing the current level of biological nitrogen fixation and adapting symbiotic systems to negative environmental factors is currently relevant. The use of nanotechnology, in particular, the study of the effect of iron, germanium, and cobalt nanocarboxylates on the formation and functioning of the soybean-rhizobial symbiosis under field conditions in combination with seed inoculation with rhizobial bacteria may be promising. Materials and Methods. The objects of the investigation were symbiotic systems created with the participation of the Almaz variety of soybean and the Bradyrhizobium japonicum B1-20 rhizobacteria, and with the introduction of nanocarboxylates of iron (Fe), germanium (Ge) and cobalt (Co) into their cultivation medium. Physiological, microbiological, biochemical, and statistical research methods were used. Results. It was found that under field conditions, before the pod formation stage, the vegetative mass of soybean plants inoculated with rhizobial bacteria with the introduction of nanoparticles of carboxylates of iron, germanium, or cobalt into their cultivation medium was at the level of control plants or slightly exceeded them. It has been shown that under the effects of chelated micronutrients, the number of root nodules increased compared to control plants during the flowering and pod formation stages, and their mass was greater from the three trifoliate leaf stage, which ensured efficient functioning of the legume-rhizobial symbiosis. It has been noted that the used metal nanocarboxylates promote active functioning of the symbiotic apparatus in soybean plants, as an increase in nitrogen-fixing activity was observed at the stages of three trifoliate leaf development and flowering, ranging from 26–70 % depending on the microelement used. Conclusions. During field cultivation of soybeans, the effectiveness of pre-sowing seed inoculation with Bradyrhizobium japonicum B1-20 rhizobia was demonstrated through the introduction of iron, germanium, or cobalt nanocarboxylates into their cultivation medium. This opens up opportunities for increasing the efficiency of symbiotic systems of soybeans.

Pyrolysis temperature affects biochar suitability as an alternative rhizobial carrier

Biochars produced from different feedstocks and at different pyrolysis temperatures may have various chemical and physical properties, affecting their potential use as alternative microbial carrier materials. In this study, biochars were produced from pine wood and oak feedstocks at various temperatures (400°C, 500°C, 600°C, 700°C and 800°C), characterized, and assessed for their potential as carriers for Bradyrhizobium japonicum (CB1809) strain. The biochars were then stored at two different storage temperatures (28°C and 38°C) for up to 90 days. Furthermore, the study also explored the role of potentially ideal carriers as inoculants in the growth of Glycine max L. (soybean) under different moisture levels i.e., 55% water holding capacity (WHC) (D0), 30% WHC (D1) and, 15% WHC (D2) using a mixture of 50% garden soil and 50% sand. The results were compared to a control group (without inoculants) and a peat inoculant. Among all the materials derived from pine wood and oak, pine wood biochar pyrolyzed at 400℃ (P-BC400) exhibited the highest CFU count, with values of 10.34 and 9.74 Log 10 CFU g− 1 after 90 days of storage at 28℃ and 38℃, respectively. This was notably higher compared to other biochars and peat carriers. Significant (p < 0.05) increases in plant properties: shoot and root dry biomass (174% and 367%), shoot and root length (89% and 85%), number of leaves (71%), membrane stability index (27%), relative water content (26%), and total chlorophyll (140%) were observed in plants treated with P-BC400 carrier inoculant compared to the control at D2; however, lower enrichment of δ13C (37%) and δ15N (108%) with highest number of root nodules (8.3 ± 1.26) and nitrogenase activity (0.869 ± 0.04) were observed under D2, as evident through PCA analysis, showing more nitrogen (N) fixation and photosynthetic activity. Overall, this experiment concluded that biochar pyrolyzed at lower temperatures, especially P-BC400, was the most suitable candidate for rhizobial inoculum and promoted soybean growth.

STUDY OF THE EFFECT OF BIOLOGICAL PREPARATIONS ON THE DEVELOPMENT OF SOYBEAN PLANTS

The article analyzes the peculiarities of the influence of biological preparations on the growth and development of soybean plants of various varieties. In particular, such varieties as mid-ripe Sensor and mid-early Onix were studied. The influence and features of the activation of vital processes of soybean plants when using Rehoplant (a balanced composition of biologically active compounds - low molecular weight organic substances, amino acids, fatty acids, oligosaccharides, chitosan and a complex of biogenic microelements in ionic form and aversectins) and bioinoculant Anderiz (includes 3 strains of nodular bacteria Bradyrhizobium japonicum). It was established that the average duration of the growing season over the years of research was 112-113 days for the medium-ripening variety Sensor and 117-118 days for the medium-early variety Onix. The duration of the vegetation period of the studied soybean varieties changed by 1-2 days for cultivation in variants with pre-sowing treatment of seeds with biostimulant and bioinoculant. According to the results of the research carried out in the experimental plots, the effect of seed treatment with biostimulant and bioinoculant on the field germination, density and survival of plants of the investigated soybean plants was revealed. It was established that, on average, in 2022-2023, depending on the action of intensification factors, the field germination of soybeans also changed, in the Sensor variety from 84.4 to 88.1% and in the Onix variety from 89.9 to 92.1%, which affected on the formation of the plant density index for the period of full emergence of the Sensor variety - 51.8-53.9 pcs/m2 and the Onix variety - 55.1-56.4 pcs/m2. Seed treatment to some extent reduces the negative impact of mineral fertilizers and ensures an increase in the field germination of soybean plants. This phenomenon is due to the activation of physiological and biochemical processes in soybean seeds and seedlings due to the inoculation of seeds with a strain of nodule bacteria in a bioinoculant and treatment with trace elements. As a result of the research, it was found that the maximum plant height in the experiment in soybean varieties was recorded in the phase of bean filling, practically until the end of the growing season, the growth of the main stem did not take place. The lowest plant height indicators were observed on the control variant.

Influence of Bradyrhizobium japonicum on the growth parameters and formation of the assimilation apparatus in E-gene isogenic lines of soybean

The study investigated the impact of the interaction between soybean and rhizobia on the assimilation apparatus functioning and biomass accumulation in different soybean lines with varying photoperiod sensitivity. Nearly isogenic lines (NILs) of soybean were used, with genes E1, E2, and E3 in different allelic states: Clark (e1E2E3), L80-5879 (E1e2e3), L63-3117 (e1e2E3), and L71-920 (e1e2e3). The experimental group for each line was treated with Bradyrhizobium japonicum 634b. Plants were grown under natural long-day conditions (16 hours). Growth indicators of the studied lines, such as relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), and specific leaf area (SLA), were analyzed, as well as the content of chlorophylls A and B in the V3 and V5 developmental stages. The results demonstrate that the influence of rhizobia on the functioning of the assimilation apparatus and biomass accumulation depends on the soybean line genotype. In the study, RGR, which characterizes the biomass accumulation rate, has similar trends to those observed with NAR, characterizing the assimilation apparatus's functioning. However, each line showed its own tendencies. For instance, in the short-day variety Clark, under bacterial influence, the value of RGR and NAR decreased. Additionally, LAR and SLA values indicated a reduction in the total photosynthetic surface area and leaf dry matter. Bacterial inoculation did not significantly affect the content of photosynthetic pigments in Clark leaves. Another short-day line, L80-5879, showed no significant impact of bacterial inoculation on biomass accumulation. However, soybean interaction with Bradyrhizobium japonicum 634b led to a decrease in leaf surface area and dry matter content. Probably, bacterial inoculation supported assimilation processes by increasing auxiliary chlorophyll b in photosystem I. A general trend of significant RGR reduction in neutral-day soybean lines, L63-3117 and L71-920, was identified under bacterial influence. The interaction with rhizobia differently affected LAR and SLA values, indicating distinct adaptive mechanisms to the interactions. In conditions of almost zero plant biomass accumulation, Bradyrhizobium japonicum 634b caused a decrease in the total photosynthetic surface area and chlorophyll a and b content in the L63-3117 line. In L71-920, bacterial inoculation had no effect on the total photosynthetic surface area, while leaf dry matter and photosynthetic pigment content decreased. The obtained results demonstrate that interaction with rhizobia can influence the functioning of the assimilation apparatus in soybeans with varying photoperiod sensitivity that is determined by genotype. It is important in improving soybean productivity and its application in agricultural practices.

The rainstorm influence on ecological restoration: A novel response ecological model for an urban shallow lake

AbstractEnvironmental processes in cities and suburbs are significantly impacted by climate change. The development of reliable ecological models may successfully direct agricultural activities. Numerous models have been put forth as of late; however, because to the complexity of environmental microorganisms, their use in complex systems is still restricted. For a better understanding of the ecological restoration of an urban lake system that had been disturbed by rainfall, an improved ecological dynamic model that took into account inundation plants, phytoplankton and microorganisms was proposed based on the field survey. Observed data from a shallow urban lake with a surface area of approximately 66 600 m2 in the heart of Shunde district, Foshan, in South China, was used to validate the model. In this model, five hypotheses—phytoplankton, microorganisms, NH3‐N, COD and TP in water—were selected as experimental variables. To assess the model's correctness and dependability, the correlation coefficients (R) and root mean square error‐observations standard deviation ratio (RSR) were computed. The results from the establish model (0.446 &lt; R &lt; 0.985, RSR &lt; 0.7) are very similar to those of actual observations. In addition, four microbe species (Aquabacium, Bradyrhizobium japonicum, Curvibacter and Cyanobacteria) multiplied when pollutant concentration dropped. Our model provides a useful tool for managing urban shallow water lakes by properly simulating the dynamic changes of aquatic species and microbes in urban shallow water lakes.

Impact of pre-inoculation of soybean seeds with Bradyrhizobium spp. applied 60 days before sowing

The pre-inoculation of soybean seeds optimizes sowing process, enhancing biological nitrogen fixation, seed quality, and overall crop yield. This study aimed to evaluate the efficacy of pre-inoculating soybean seeds with the commercial inoculant Biofix Premium (Bradyrhizobium diazoefficiens SEMIA 5080 and Bradyrhizobium japonicum SEMIA 5079, 5x10^9 CFU/mL), along with a cell protector and chemical treatment. Four soybean trials were performed in Paraná, São Paulo, Minas Gerais, and Goiás states during the 2021/2022 agricultural year, utilizing a randomized complete block design with four treatments and six replications. The treatments were: 1- Control (no inoculation); 2- Fertilization with 200 kg.ha-1 of nitrogen; 3- Commercial standard seed inoculation (50 mL/50 kg of seeds) on the sowing day; 4- Seed inoculation with Biofix Premium (125 mL/100 kg of seeds), Protetor Ultra (0.5 mL/kg), Potenzial TS (0.2 mL/kg), and CoMo Platinum (100 mL/ha), applied 60 days before planting. Results showed that Biofix Premium applied 60 days before sowing, formed nodules and nodule mass similar to the comercial inoculant applied at sowing day. This led to a similar nitrogen fixation, chlorophyll content, shoot dry mass accumulation, grain yield, and nitrogen content compared to the comercial inoculant applied at sowing day. Yield gains with Biofix Premium ranged from 5-8% compared to the control (without inoculation), with no significant differences from the commercial seed inoculation applied on the sowing day. The use of insecticides and fungicides together with Biofix Premium, Protector Ultra, and Potenzial TS is recommended in the pre-inoculation of soybean seeds up to 60 days before sowing, without compromising plant nodulation and crop yield

Harnessing the Biocontrol Potential of Bradyrhizobium japonicum FCBP-SB-406 to Manage Charcoal Rot of Soybean with Increased Yield Response for the Development of Sustainable Agriculture.

Plant growth-promoting bacteria (PGPRs) have the potential to act as biofertilizers and biopesticides. This study was planned to explore indigenously isolated PGPRs as a potential candidate to control charcoal rot that affects various crops including soybean. Among the four different tested species of PGPRs, Bradyrhizobium japonicum (FCBP-SB-406) showed significant potential to enhance growth and control soil borne pathogens such as Macrophomina phaseolina. Bacillus subtilis (FCBP-SB-324) followed next. Bradyrhizobium japonicum (FCBP-SB-406) reduced disease severity up to 81.25% in comparison to the control. The strain showed a strong fertilizing effect as a highly significant increase in biomass and other agronomic parameters was recorded in plants grown in its presence. The same was supported by the Pearson's correlation and principal component analysis. A decrease in disease incidence and severity may be due to the induced resistance imparted by the bacterium. This resulted in significant increments in quantities of defense enzymes, including catalase, peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and superoxide dismutase (SOD). A significant production of proteases, catalases and hydrogen cyanide by B. japonicum (FCBP-SB-406) can also be associated to mycoparasitism. The establishment of PGPRs in treated soils also showed positive effects on soil health. Total metabolite profiling of treated plants in comparison to the control showed the upregulation of many flavonoids, isoflavonoids and amino acids. Many of these compounds have been well reported with antimicrobial activities. Bradyrhizobium japonicum (FCBP-SB-406) can be employed for the production of a potential formulation to support sustainable agriculture by reducing the input of synthetic pesticides and fertilizers.

Response of Some Soybean Genotypes to Insect Infestation under Three Mineral Nitrogen Fertilizer Rates

Background: A two-year study was conducted at Giza Agricultural Research Station, Agricultural Research Center (ARC), Egypt, to evaluate the productivity of six genotypes of soybeans under three mineral nitrogen (N) fertilizer rates, as well as their resistance to insects, in comparison to four check varieties. Methods: The study took place during the 2021 and 2022 summer seasons. The treatments included three mineral N fertilizer rates (N1=67% of N fertilizer rate “71.4 kg N/ha”, N2=33% of N fertilizer rate “35.7 kg N/ha” with seed inoculation by Bradyrhizobium japonicum and N3=100% of N fertilizer rate of the recommended rate “107.1 kg N/ha”) and ten soybean genotypes (H4L4, H6L198, H18L54, H29L115, H129, Misr 10, along with Dr101 and Giza 111 “resistant” and Giza 82 and Crawford “susceptible”). The experiment used a split plot design with three replications. The main plots were assigned the mineral N fertilizer rates, while the subplots, were assigned the soybean genotypes. Result: Fewer cotton leaf worms, whiteflies and leaf miners were found after applying N1 or N2. In the 6th week from sowing, Misr 10 and Dr 101 had fewer cotton leaf worms and whiteflies. In contrast, throughout the 7th, 8th and 9th weeks from sowing, Misr 10 and H6L198 had fewer cotton leaf worms. Misr 10 had fewer leaf miners in every week and fewer whiteflies in the 7th, 8th and 9th weeks from sowing. In the 6th week of the first season, Misr 10, Dr101, H18L54 and Giza 111 that received N1 or N2 had fewer cotton leaf worms; in the 7th and 9th weeks from sowing, Misr 10, Dr101 and H6L198 harbored fewer whiteflies. The lowest pod weight/plant, seed yield/plant, 100-seed weight, seed yield/ha and HI were obtained by using N3. Higher biological yield/ha, seed yield/plant, 100-seed weight, seed yield/ha and HI were attained by Misr 10. In the second season, seed yield per plant and seed yield per hectare were significantly affected by the interaction between soybean genotypes and mineral N fertilizer rates. Growing Misr 10 with 67 per cent N of the recommended rate increased seed yield/plant and seed yield/ha, along with fewer cotton leaf worm, whiteflies and leaf miners compared to the commercial cultivar Giza 111 receiving the recommended mineral N fertilizer rate.

Bionanomaterial composed of Bradyrhizobium japonicum and graphene oxide for determination of mercury in water and fruit juice samples

Bionanomaterial composed of Bradyrhizobium japonicum and graphene oxide for determination of mercury in water and fruit juice samples

The Bradyrhizobium japonicum exporter ExsFGH is involved in efflux of ferric xenosiderophores from the periplasm.

The gram-negative bacterium Bradyrhizobium japonicum can take up structurally dissimilar ferric siderophores from the environment (xenosiderophores) to meet its nutritional iron requirements. Siderophore-bound iron transported into the periplasm is reduced to the ferrous form by FsrB, dissociated from the siderophore and the free ion is then transported into the cytoplasm by the ferrous iron transporter FeoAB. Here, we identified the RND family exporter genes exsFG and exsH in a selection for secondary site suppressor mutants that restore growth of an fsrB mutant on the siderophores ferrichrome or ferrioxamine. The low level of radiolabel accumulation from 55Fe-labeled ferrichrome or ferrioxamine observed in the fsrB mutant was restored to wild type levels in the fsrB exsG mutant. Moreover, the exsG mutant accumulated more radiolabel from the 55Fe-labeled siderophores than the wild type, but radiolabel accumulation from inorganic 55Fe was similar in the two strains. Thus, ExsFGH exports siderophore-bound iron, but not inorganic iron. The rescued fsrB exsG mutant required feoB for growth, indicating that ExsFGH acts on those siderophores in the periplasm. The exsG mutant was more sensitive to the siderophore antibiotic albomycin than the wild type, whereas the fsrB mutant was more resistant. This suggests ExsFGH normally exports ferrated albomycin. B. japonicum is naturally resistant to many antibiotics. The exsG strain was very sensitive to tetracycline, but not to six other antibiotics tested. We conclude that ExsFGH is a broad substrate exporter that is needed to maintain siderophore homeostasis in the periplasm.

Management of Inoculation with Bradyrhizobium japonicum and Application of Vitamins for Hydroponic Soybean Cultivation.

The exchange of technologies used in field cultivation for hydroponic systems can potentially increase plant development and grain production, requiring studies to verify the best management forms, such as growth-promoting bacteria and biostimulant compounds. With this in mind, the study aimed to evaluate the effect of the application of thiamine and niacin, alone and combined, to soybean plants in the absence and presence of inoculation with B. japonicum on the agronomic and physiological characteristics of the crop grown in an ebb and flow hydroponic system. Eight treatments were evaluated using t-test (LSD) and Tukey's test, both at 5% probability (P < 0.05), in addition to Pearson correlation and canonical variables. The treatments consist of inoculation with B. japonicum at 1 mL 500 g-1 seeds (with and without) and foliar application of four solutions (water, niacin (0.1 g·L-1), thiamine (0.1 g·L-1), and niacin + thiamine (0.05 g·L-1 + 0.05 g·L-1)). We found that inoculation significantly improved the parameters evaluated and resulted in a gain of approximately 84.8% in yield when compared by t-test (P < 0.05). In addition, the action of the vitamins was more significant when they were applied without the presence of B. japonicum, especially niacin, either alone or combined with thiamine, which increased yield parameters in this condition, identified when the Tukey's test (P < 0.05) was applied. We conclude that inoculation with Bradyrhizobium japonicum in soybean seeds grown in a hydroponic system significantly benefits the development and grain yield, mainly when combined with vitamin solutions. Niacin also has the potential to be used alone or combined with thiamine in noninoculated or inoculated hydroponic soybean crops, respectively.

Harnessing the catalytic plasticity of the ent-kaurene synthase from Bradyrhizobium japonicum to produce the ent-rosane and ent-pimarane scaffolds

The F72Y mutation of the ent-kaurene synthase from Bradyrhizobium japonicum leads to the formation of ent-rosa-5(10),15-diene and ent-pimara-8,15-diene, two common scaffolds of labdane diterpenoids.

Effect of rhizobial inoculation on the nodulation, growth and yield of Soybean in the Savannah regions of Nigeria

Rhizobial inoculation is the introduction of rhizobium bacteria in a high concentration into the soil before or during the planting of crops. Field experiments were conducted during the rainy seasons of 2020, 2021, and 2022 at the Research farm of the Department of Crop Sciences, Faculty of Agriculture, University of Abuja, Gwagwalada, the Southern Guinea Savanna of Nigeria. The study aimed to analyse the effect of Bradyrhizobium japonicum inoculation on the nodulation, growth and yield parameters in Soybean. The treatments consisted of three Soybean varieties, namely TGX 1485-1D (early maturing), TGX 1448–2E (medium maturing), and TGX1987–10F (medium maturing) and Two levels of inoculant (control, with inoculant), The experiment was laid out in a randomized complete block design (RCBD), with three replicates and 54 plots. Agronomic and cultural practices were duly observed, and data were collected for growth and yield parameters. Data were subjected to analysis of variance (ANOVA) using the ‘agricolae’ package in the R Statistical Programme (R version 4.2.2.), T-test was conducted using the SPSS statistical package (Version 23), and the Duncan Multiple Range Test (DMRT) and Standard error (SE) were used to separate significant means at (P ≤ 0.05). Results showed that for all varieties of Soybean observed, the inoculated had the best performance (2685kg/ha, 2842.3kg/ha, 3038.5Kg/ha for TGX 1485-1D, TGX 1448–2E and TGX1987–10F respectively best compared to the control.

Characterization, Selection and Evaluation of Temperature Tolerant Bradyrhizobium Japonicum Strains to Promote Soybean Cultivation in Tropical Soils Condition

Characterization, Selection and Evaluation of Temperature Tolerant Bradyrhizobium Japonicum Strains to Promote Soybean Cultivation in Tropical Soils Condition

Evaluation of different lines of vegetable soybean Glycine max L. Merr. under conditions of the Moscow region

Edamame is a special soybean ( Glycine max (L.) Merr .) harvested as a vegetable when the seeds are immature (R6 and R7 stage) and have expanded to fill 80 to 90 percent of the pod width. The study was conducted in the experimental field of Federal Scientific Vegetable Center in the Moscow Region in 2020-2022 and Agro-biotechnological department, Agrarian and Technological Institute, RUDN University. The object of research was 3 accessions of soybean ( Glycine max L.): accession A, accession F, Hidaka and Lira. Before sowing, soybean seeds were inoculated with Optimays 400 ( Bradyrhizobium japonicum ) and Biobesta ( Sinorhizobium fredii ). In the field experiment, 10 soybean samples were taken from each plot at the stage of biological ripeness to determine plant height (cm), number of pods per plant, number of stems per plant, stem width (mm), average number of seeds per plant, weight of 1000 seeds (g) and yield (t/ha). The experiment was designed in a complete random block with a factorial arrangement. Thus, we had 4 accessions and 3 treatments (C - control, V1 - Bradyrhizobium japonicum and V2 - Sinorhizobium fredii ) with 3 replacations. The study showed that accession A had the highest average yield per hectare (2.70 t/ha) and weight of 1000 seeds (159 g). Under conditions of the Moscow region, variant V2 ( Sinorhizobium fredii ) had the highest average yield (2.57 t/ha) and weight of 1000 seeds (100.25 g). Therefore, more than 90 % of the results obtained for these two indicators are associated with the use of V2 treatment. For the rest of the studied indicators, no significant differences were found, and they did not affect the efficiency indicators. The combination of accession A and treatment V2 led to the highest average yield (2.99 t/ha). The product based on Sinorhizobium fredii showed the best indicators for all the studied samples.

THE INFLUENCE OF PENICILLIUM FUNGI ISOLATED FROM SOYBEAN ROOTS ON THE SYMBIOTIC SYSTEM “GLYCINE MAX – BRADYRHIZOBIUM JAPONICUM” AND CROP PRODUCTIVITY

Objective. Identify new strains of Penicillium endophytic fungi by morphological and cultural properties, study their influence on the symbiotic system “Glycine max – Bradyrhizobium japonicum” and soybean productivity. Methods. Microbiological (cultivation of endophytic fungi, preparation of spore suspensions, determination of spore titre in suspensions, light microscopy), gas chromatographic (determination of nitrogenase activity of soybean nodules), vegetation and field small-plot experiments (study of the effect of endophytic fungi on symbiotic and morphometric parameters of soybean plants and crop yield when growing on sod-podzolic soil), statistical. Results. New strains of Penicillium endophytic fungi are attributed to the species P. funiculosum Thom, P. variabile Sopp, P. glauco-lanosum Chalabuda, and P. steckii Zaleski based on their morphological and cultural characteristics. Under the conditions of the vegetation experiment, the positive influence of the studied strains on the symbiotic parameters of soybeans was shown. A tendency towards an increase in the number of nodules versus the control in all variants, an increase in the mass of nodules in the variants when soybean seeds were treated with spores of P. variabile 20173 and P. funiculosum 20312 by 28.4 % and 36.4 %, respectively, an increase in the nitrogenase activity of nodules by 29.8–38.5 % in variants with the use of P. stekii 2204, P. glauco-lanosum 20401, P. variabile 20173 was registered. The results of the study of soybean symbiotic parameters under the conditions of the field experiment generally confirmed the corresponding data of the vegetation experiment. Inoculation of soybean seeds with spores of Penicillium endophytic fungi contributed to an increase of the morphometric parameters of plants, namely: height — by 4.6–6.2 cm in all variants of the experiment, above-ground mass of dried plants — by 11.1–19.0 % when treated with P. stekii 2204, P. glauco-lanosum 20401, P. variabile 20173, mass of dry roots — by 13.2 % and 18.4 % with P. funiculosum 20312 and P. variabile 20173. The results of the field experiment proved the positive influence of new strains of endophytic fungi on soybean yield: when soybean seeds were inoculated with P. variabile 20173, P. funiculosum 20312 and P. stekii 2204, the increase in grain productivity was on average from 11.8 % to 17.3 %. The weight of 1000 grains increased by 3.8–5.1 % in variants using P. variabile 20173, P. glauco-lanosum 20401, P. stekii 2204. Conclusion. Penicillium endophytic fungi, which belong to the species P. funiculosum, P. variabile, P. glauco-lanosum and P. stekii, were isolated from the tissues of soybean roots. It was found that Penicillium endophytic fungi have a positive influence on the functioning of the symbiotic system “Glycine max – Bradyrhizobium japonicum” and soybean yield.

COMPLEX INOCULATION OF SOYBEANS WITH NODULE BACTERIA BRADYRHIZOBIUM JAPONICUM AS A MEASURE TO OPTIMIZE SYMBIOTIC NITROGEN FIXATION

Objective. Establish effective mixed inoculants for soybeans based on new active strains of Bradyrhizobium japonicum with different intensity and dynamics of nitrogen-fixing activity to improve nodulation processes and functional activity of legume-rhizobia symbiosis. Methods. Microbiological, physiological, statistical, gas chromatography. Legume-rhizobia systems based on Glycine max L. (Merill) soybean, variety Samorodok, were studied using recombinant strains of B. japonicum: B199, B201, Д47, Д48, Д52, Д60, Д63. Monoinoculation of soybean with B. japonicum 634б served as the control. Results. Mixed inoculation of B. japonicum ensured positive ontogenetic dynamics of root nodule formation in soybean. The indicator of the number of root nodules in experimental plants was 1.2–1.9 times higher versus the control plants from Day 18 to 45 of soybean vegetation. When soybeans were inoculated with B. japonicum 634б + B201 and 634б + Д 52, the mass of nodules at Day 45 of vegetation increased by 30.0–35.3 % versus the control and was the highest (1.10–1.15 g/plant) among the studied variants, as a result of the strengthening effect of complex bacterization. A positive synergistic effect of the combined use of strains was obtained — intensification of the nitrogen-fixing activity of soybean root nodules. In the phase of budding/beginning of flowering and full flowering under combined inoculation with active strains of B. japonicum 634б + Д47, 634б + Д52 and 634б + В201, nitrogen fixation of soybean nodules increased by 10.7–25.5 % (at Day 32), by 13.2–30.9 % (at Day 38), and was also 2.3–2.8 times higher in the phase of full flowering (Day 45 of soybean vegetation) versus the similar indicator of control plants. In the phase of full flowering of plants (Day 45 of vegetation), under mixed inoculation with strains of B. japonicum 634б + Д47, 634б + В201, 634б + Д52 and В201 + Д52, the aboveground mass of plants exceeded that of control plants by 8.3–17.2 % variant, which was probably provided by improved conditions of their nitrogen nutrition, due to enhanced assimilation of N2 by root nodules. The most developed root system was in soybeans inoculated with strains B. japonicum 634б and B. japonicum 634б + Д52, B. japonicum 634б + В201 and B. japonicum Д48 + Д52. Conclusion. Symbiotic features of active recombinant strains of B. japonicum and their variability in functional activity at different stages of soybean ontogenesis should be taken into account when creating complex nitrogen-fixing bacterial preparations for soybeans with the effect of microbiological synergy.

Biopolymer as an additive for effective biochar-based rhizobial inoculant

Biochar is an efficient and inexpensive carrier for bacteria that stimulate plant development and growth. In this study, different biopolymer additives (cellulose, xanthan gum, chitin and tryptone) were tested with different addition ratios (1:0.1, 1:0.5 and 1:1) on further enhancing biochar capacity for supporting the growth and activity of Bradyrhizobium japonicum (CB1809). We utilized pine wood biochar (PWBC) pyrolyzed at 400 °C as the base inoculum carrier. The shelf life and survival rate of CB1809 were counted using the colony-forming unit (CFU) method for up to 120 days. Peat served as a standard reference material against which all treatments were compared. Subsequent experiments evaluated the ability of carrier inoculants to promote Glycine max L. (soybean) plant growth and nodulation under different watering regimes, i.e., 55 % water holding capacity (WHC) (D0), 30 % WHC (D1) and, 15 % WHC (D2) using sandy loam soil. Results revealed that among different additives; xanthan gum with 1:0.5 to PWBC [PWBC-xanthan gum(1:0.5)] was observed as a superior formulation in supporting rhizobial shelf life and survival rate of CB1809. In pot experiments, plants with PWBC-xanthan gum(1:0.5) formulation showed significant increase in various physiological characteristics (nitrogenase activity, chlorophyll pigments, membrane stability index, and relative water content), root architecture (root surface area, root average diameter, root volume, root tips, root forks and root crossings), and plant growth attributes (shoot/root dry biomass, shoot/root length, and number of nodules). Additionally, a reduced enrichment of isotopic signatures (δ13C, δ15N) was observed in plants treated with PWBC-xanthan gum(1:0.5), less enrichment of δ15N indicates an inverse link to nodulation and nitrogenase activity, while lower δ13C values indicates effective water use efficiency by plants during drought stress. These results suggest that biopolymers supplementation of the PWBC is useful in promoting shelf life or survival rate of CB1809.