Japonicum Strains Research Articles

Transgenic Arabidopsis thaliana plants expressing bacterial γ-hexachlorocyclohexane dehydrochlorinase LinA

Backgroundγ-Hexachlorocyclohexane (γ-HCH), an organochlorine insecticide of anthropogenic origin, is a persistent organic pollutant (POP) that causes environmental pollution concerns worldwide. Although many γ-HCH-degrading bacterial strains are available, inoculating them directly into γ-HCH-contaminated soil is ineffective because of the low survival rate of the exogenous bacteria. Another strategy for the bioremediation of γ-HCH involves the use of transgenic plants expressing bacterial enzyme for γ-HCH degradation through phytoremediation.ResultsWe generated transgenic Arabidopsis thaliana expressing γ-HCH dehydrochlroninase LinA from bacterium Sphingobium japonicum strain UT26. Among the transgenic Arabidopsis T2 lines, we obtained one line (A5) that expressed and accumulated LinA well. The A5-derived T3 plants showed higher tolerance to γ-HCH than the non-transformant control plants, indicating that γ-HCH is toxic for Arabidopsis thaliana and that this effect is relieved by LinA expression. The crude extract of the A5 plants showed γ-HCH degradation activity, and metabolites of γ-HCH produced by the LinA reaction were detected in the assay solution, indicating that the A5 plants accumulated the active LinA protein. In some A5 lines, the whole plant absorbed and degraded more than 99% of γ-HCH (10 ppm) in the liquid medium within 36 h.ConclusionThe transgenic Arabidopsis expressing active LinA absorbed and degraded γ-HCH in the liquid medium, indicating the high potential of LinA-expressing transgenic plants for the phytoremediation of environmental γ-HCH. This study marks a crucial step toward the practical use of transgenic plants for the phytoremediation of POPs.

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.

Viability of Nodule Bacteria Bradyrhizobium japonicummon Soybean Seeds by Treatment With Fungicides During Extended Storage

Background. With the increase in soybean cultivation areas, inoculants are becoming increasingly sought after. They are not only compatible with the original preparations for seed treatment of soybean but also offer the possibility of applying them for several days or even months before sowing into the soil. Objective. The viability of new strains of nodule bacteria Bradyrhizobium japonicum (strain PC07 and strain B78) was investigated on the surface of soybean seeds treated with fungicides Fever and Maxim XL during the extended storage of inoculated seeds. Additionally, their ability for nitrogen fixation under symbiotic conditions was evaluated. Methods. Сultivation, serial dilution method, determination of bacterial titer of inoculants, quantification of colony forming units (CFU), gas chromatography. Results. In laboratory conditions, on the soybean seeds of Almaz and Vasylkivska varieties, the viability of the nodule bacteria B. japonicum PC07 and B78, which are more resistant to the active substances of these fungicides in pure culture, decreased. This reduction was dependent on the storage period, the fungicide used, and the strain of inoculant. One day after inoculation on the seeds without the use of fungicide, 68.6–75.4% CFU of the initial number was retained. Seeds treated with the fungicide Fever contained 36.5–38.3% CFU, and those treated with Maxim XL contained 26.2–27.0% CFU. The use of inoculants based on fungicide-resistant strains of B. japonicum PC07 and B78 also provided high cell viability – 2.41–2.8×106 (on the seeds without treatment), 1.40–1.70×106 (with Fever) and 0.8–1.17×106 (with Maxim XL) CFU/seed after 5 days of storage. The nitrogen-fixing activity of root nodules in soybean plants of Almaz and Vasylkivska varieties, whose seeds were treated with Fever, decreased on both varieties by 18.4–22.4% and 32.1–39.5%, respectively and for treatment with Maxim XL, the reduction was 24.5–33.7% and 47.7–75.2%, respectively, during the storage of seeds for 5 and 7 days before sowing, compared to control variants (seeds without fungicide treatment). Conclusions. The utilization of fungicide-resistant strains of B. japonicum PC07 and B78 for bacterization of soybean seeds treated with fungicides Fever and Maxim XL provides a high inoculation titer during 5 days of storage. Viability of microbial cells on seeds treated with fungicides significantly diminishes during storage for more than 7–14 days. Insufficient titer of CFU of B. japonicum strains PC07 and B78 on the seed surface after 14 days of storage can considerably impede the efficacy of biopreparations. Therefore, it is crucial to seek substances that can enhance the resistance of rhizobia on seeds to the adverse effects of fungicide seed treatment, ensuring a longer period of their viability.

Isolation and Diagnosis of the Root Nodule Bacteria Associated with Mung Bean Plant in Gypsiferous Soil and Testing the Promotional Criterion of Isolates

The root nodule bacteria are utilized in the production of natural biological fertilizers to achieve clean agriculture by reducing chemical fertilizers. In this study, 35 samples of the root nodules associated with mung bean plants were collected from various agricultural areas of Iraq, Salah Al-Din Governorate on 4\\7\\2022, ten samples isolated by growing them on yeast extract mannitol agar (YEMA) and the phenotypically pure isolates were diagnosed based on the culture, microscopic and biochemical characteristics., The phenotypic diagnosis results showed that The color of the colonies was between white, creamy and yellow, Spherical, convex and smooth, gram-negative, was able to move and pink and light pink on Congo red stain medium and 9 isolates it was fast growing as it gave yellow color on YEMA-BTB bromothymol blue medium except for one isolate it was slow growing as it gave blue color and all isolates unable to grow on Hofer alkaline medium except for one isolate, The efficient isolate was selected in the production of indole acetic acid, chelating compounds and phosphate solubilization,. The results showed that isolates (M3, M4, M5, M6, M7) have a high ability for iron chelation. It was found that the (M6) isolate gave the highest phosphate solubilization and indole production, which showed a phosphorus solubilization of 39.504 mg P.L-1 and an indole production rate of 21.5 μg.ml-1. This was followed by the isolate (M3), which showed a phosphorus solubilization of 23.723 mg P.L-1 and an indole production rate of 17.2 μ.g.ml-1. Molecular diagnosis was performed for five competent isolates in the production of Indole acetic acid, production of chelating compounds, and phosphate solubilization. The isolates were molecularly diagnosed by PCR, the 16SrRNA gene was amplified, then the sequence of nitrogenous bases was analyzed and when matching with the global strains included in the NCBI Genetic Bank website, The results of molecular diagnosis showed that two isolates belong to Rhizobium bacteria. the results showed that (M3) isolate is %99.50 similar to the Rhizobium leguminosarum isolate OTU21_I. and the results showed that (M6) isolate is 99.48% similar to the Bradyrhizobium japonicum strain A3 and 99.96% to the Bradyrhizobium japonicum, strain:NK5 and therefore the isolates is genetically close to Rhizobium leguminosarum strain AE15 and Bradyrhizobium japonicum strain AE14 bacteria and has been recorded in the Global genome bank under accession number OP975690 and version number OP975690.1 for Rhizobium leguminosarum and accession number OP975688 and version number OP975688.1 for Bradyrhizobium japonicum and this record is the first for this bacteria which associated with mung bean in gypsiferous soils in Iraq.

Integrated use of Consortia-based Microbial Inoculants and Nutrient Complex Stimulates the Rhizosphere Microbiome and Soybean Productivity

Background: The effectiveness of soybean inoculants in field conditions may be improved through the joint application of rhizobia and plant growth-promoting bacteria (PGPB). Plant nutrients may also contribute to the higher efficacy of microbial inoculants as well as the growth and development of plants. Methods: A field experiment was performed to evaluate the responses of the rhizomicrobiome and soybean to seed treatments with multiple bacterial strains (Bradyrhizobium japonicum, Bacillus subtilis, Bacillus megaterium and Azotobacter chroococcum), applied individually or in consortia, with and without nutrient complex (S, Mg, Mn, Fe, Zn, Cu, B and Mo). Result: Seed treatments with microbial consortia of Br. japonicum, B. subtilis/B. megaterium, A. chroococcum strains and nutrients had the highest effect on the abundance of total bacteria, nitrogen-fixing bacteria, actinomycetes and activity of dehidrogenase in the soybean rhizosphere. The highest effect on plant height, plant weight, pod number, pod weight, seed number and seed weight was obtained from treatment with Br. japonicum strains with nutrients, followed by co-inoculation with B. megaterium and A. chroococcum. In comparison with the control and Bradyrhizobium single inoculation, a statistically significant increase in the seed yield was recorded in treatment with Br. japonicum, B. megaterium, A. chroococcum and nutrients, reflecting the highest increase in protein and oil yield. The interactive effects of microbial consortia and nutrients could be used as promising seed technology for sustainable soybean cropping.

Impact of nitrogen-fixation bacteria on nitrogen-fixation efficiency of Bambara groundnut [Vigna subterranea (L) Verdc] genotypes.

Nitrogen fixation by bacteria is essential for sustaining the growth, development, and yield of legumes. Pot experiments were carried out at the International Institute of Tropical Agriculture (IITA) in the glasshouse between August to December 2018/2019 cropping season in Ibadan, Nigeria. Field studies were also performed in two different agroecological zones, "Ibadan and Ikenne" between August and December of 2019/2020 cropping season. The studies were set up to determine the potential of nitrogen-fixation bacteria strain inoculation on the nitrogen-fixation potential of 10 Bambara groundnut (BGN) genotypes, namely, TVSu-378, TVSu-506, TVSu-787, TVSu-1,606, TVSu-1,698, TVSu-1739, TVSu-710, TVSu-365, TVSu-475, and TVSu-305. The strains were inoculated as a broth to seedlings of each BGN genotype in the pot experiment. While six seeds from each BGN genotype were coated with each of the following nitrogen-fixation bacteria (Bradyrhizobium japonicum strains), FA3, USDA110, IRJ2180A, and RACA6, nitrogen fertilizer (urea, 20 kg/ha) was applied as a check to the nitrogen-fixation bacteria to seedlings of BGN genotypes 2 weeks after planting in both glasshouses and fields. Uninoculated plants served as controls (zero inoculation and zero fertilization). The field experiments were arranged in Randomized Complete Block Design (RCBD), while the glasshouse experiments were arranged in Complete Randomized Design (CRD) in triplicate. The result gotten showed that higher nodule numbers and weight were recorded in TVSu-1739 and TVSu-475 in both locations and seasons compared to other genotypes; the highest nitrogen fixed values were recorded among BGN genotypes TVSu-1739, TVSu-1,698, TVSu-787, TVSu-365, TVSu-305, TVSu-710, and TVSu-1,606, with a range of (62-67 kg ha-1), and were mostly enhanced by RACA6 and USDA110 strains compared to other strains that were used.

Construction and characterization of microsatellite markers for the Schistosoma japonicum isolate from a hilly area of China based on whole genome sequencing.

Schistosoma japonicum had once caused the greatest disease burden in China and has still been transmitted in some hilly areas, for example, in Shitai of Anhui province, where rodents are projected to be the main reservoir. This may lead to a critical need of molecular tools with high efficiency in monitoring the dynamic of the rodent-associated S. japonicum, as an appropriate amount of schistosome input can re-establish its life cycle in a place with snails and then result in the re-emergence of schistosomiasis. Therefore, the goal of this study was to develop high polymorphic microsatellites from the whole genome of rodent-associated S. japonicum strain to monitor its transmission dynamic. We sampled the hilly schistosome isolate from Shitai of Anhui in China and sequenced the parasite with the next-generation sequencing technology. The whole genome was assembled with four different approaches. We then developed 71 microsatellite markers at a genome-wide scale throughout two best assembled genomes. Based on their chromosome mapping and the expected length of targeted sequences, we selected 24 markers for the development of multiplex reactions. Two multiplexes composed of 10 loci were finally developed, and their potential was revealed by their successful application on and capturing the genetic diversity of three schistosome populations. The selected 10 markers, each with clear chromosome location and characteristics, will be greatly useful in tracing the dispersal pathways or/and dynamics of the rodent-associated S. japonicum or others in the hilly area of China or elsewhere.

Genetic variation and genetic complexity of nodule occupancy in soybean inoculated with USDA110 and USDA123 rhizobium strains

BackgroundSymbiotic nitrogen fixation differs among Bradyrhizobium japonicum strains. Soybean inoculated with USDA123 has a lower yield than strains known to have high nitrogen fixation efficiency, such as USDA110. In the main soybean-producing area in the Midwest of the United States, USDA123 has a high nodule incidence in field-grown soybean and is competitive but inefficient in nitrogen fixation. In this study, a high-throughput system was developed to characterize nodule number among 1,321 Glycine max and 69 Glycine soja accessions single inoculated with USDA110 and USDA123.ResultsSeventy-three G. max accessions with significantly different nodule number of USDA110 and USDA123 were identified. After double inoculating 35 of the 73 accessions, it was observed that PI189939, PI317335, PI324187B, PI548461, PI562373, and PI628961 were occupied by USDA110 and double-strain nodules but not by USDA123 nodules alone. PI567624 was only occupied by USDA110 nodules, and PI507429 restricted all strains. Analysis showed that 35 loci were associated with nodule number in G. max when inoculated with strain USDA110 and 35 loci with USDA123. Twenty-three loci were identified in G. soja when inoculated with strain USDA110 and 34 with USDA123. Only four loci were common across two treatments, and each locus could only explain 0.8 to 1.5% of phenotypic variation.ConclusionsHigh-throughput phenotyping systems to characterize nodule number and occupancy were developed, and soybean germplasm restricting rhizobium strain USDA123 but preferring USDA110 was identified. The larger number of minor effects and a small few common loci controlling the nodule number indicated trait genetic complexity and strain-dependent nodulation restriction. The information from the present study will add to the development of cultivars that limit USDA123, thereby increasing nitrogen fixation efficiency and productivity.

Gas exchange and carbon assimilation of Bambara groundnut landraces co-inoculated with Bradyrhizobium japonicum and Bacillus subtilis under simulated drought stress

Currently, the world experiences unpredictable and severe climatic events that have led to a decline in the yield of especially crops grown in low-nutrients soils under rainfed conditions. Studies have shown that the growth, photosynthetic performance and yield of crops established in unfavourable conditions can be enhanced by inoculation with plant growth-promoting rhizobacteria. In particular, some authors have reported that the inoculation of crops with PGPR strains under drought conditions enhance their growth, yield and photosynthetic performance.This study assessed the effect of co-inoculation with Bradyrhizobium japonicum and Bacillus subtilis on the gas exchange measurements, shoot biomass and carbon assimilation of two Bambara groundnut (Vigna subterranea (L.) Verdc) landraces grown under simulated drought stress. The experiment was laid out in a 5 × 3 × 2 factorial arrangement of completely randomized design (CRD) with four replicates. Treatments included Bacillus subtilis BD234 strain (BA), Bradyrhizobium japonicum (BR), co-inoculation of B. subtilis BD234 and B. japonicum strain, ammonium nitrate (NH4-NO3) (positive control), and no inoculation (negative control). The simulated drought stress was divided into three levels namely 100% pot capacity (well-watered), 50% pot capacity (moderate stress), and 25% pot capacity (severe stress). Two landraces of Bambara groundnut, characterized by different seed colour (red and cream), were used. Significant variations were observed between the landraces and across the inoculation treatments. When grown under the drought stress levels and co-inoculated with B. japonicum and B. subtilis, the landraces of Bambara groundnut exhibited enhanced photosynthetic rate, transpiration rate, and intercellular CO2. Also, dual inoculation of the food crop grown under drought increased carbon accumulation. The red landrace revealed markedly improved growth and photosynthetic performance compared to its cream counterpart. Overall, co-inoculation of Bambara groundnut with B. japonicum and B. subtilis alleviated adverse effects under moderate and severe drought through improving the growth, photosynthetic performance, and carbon assimilation. Therefore, co-inoculation with B. japonicum and B. subtilis has a potential to combat negative effects of drought in Bambara groundnut.

Symbiotic interaction between a mixture of Bradyrhizobium japonicum strains and different soybean cultivars

Aim. To study the mutual relations between different soybean cultivars and two Bradyrhizobium japonicum strains after mixed inoculation, to evaluate the impact of the introduced microorganisms on the local rhizobial communities in soil, the formation and functioning symbiotic systems, and productivity of soybean. Methods. Microbiological and serological methods; field experiment, gas chromatography and mathematical-statistical methods. Results. A small- plot field experiment demonstrated that the use of a mixture of B. japonicum 46 and B. japonicum КВ11 strains pro- moted a more even distribution of the local and introduced rhizobia in the nodule populations of 12 soybean cultivars of different geographic origin. There was no domination of particular strains in the nodules, and the symbiotic systems formed were more balanced than the control without inoculation. After inoculation of the above-mentioned mixture, in most cultivars there was a considerable increase in the number of nodules (10–45 % more) and their mass (11–86 % increase). There was also an increase in the level of symbiotic nitrogen fixation with 1.2–4.2 times and an increase in the weight of grain per plant by 6–29 % (depending on the cultivar). The efficiency of a mixture of B. japonicum 46 and КВ11 strains in a preparation Rizogumin was confirmed in extensive field trials with soybean on an area of about 60 thousand ha in different regions of Ukraine. In the background of the local populations of the soybean nodulating bacteria in the areas, the application of the formulated mixture of the two rhizobia strains ensured a stable increase by 15–33 % in the soybean yield as compared with the control without the inoculation. Conclusions. A novel approach was investigated, which lies in the application of a mixture of B. japonicum 46 (genetic group USDA 6) and B. japoni- cum КВ11 (genetic group USDA 123) strains for different soybean cultivars inoculation. Combining these two strains and their introduction into agrocenoses ensured the formation of a balanced symbiotic systems (without clear domina- tion of some strains in the nodules). This was expressed in an intensified nodulation, symbiotic nitrogen fixation, and increased yield of different cultivars of soybeans by 15–33 % as compared to the control (without inoculation).

Yield response of accessions of Bambara groundnut (Vigna subterranea (L) Verdc) inoculated with Bradyrhizobium japonicum strains

Field experiments were conducted in two different agroecological locations of Ibadan and Ikenne in Nigeria from August through December during the 2019 and 2020 cropping seasons. The studies were set up to reduce reliance on inorganic nitrogen fertilizer and to embrace the use of nitrogen-fixing bacteria to improve legume production to increase farmers' output and profitability. Ten accessions of the Bambara groundnut (BGN) were used in the trials. Seeds of each BGN accession were coated with each of the following Bradyrhizobium japonicum strains (B. japonicum): FA3, RACA6, USDA110, and IRJ2180A before planting. Furthermore, Nitrogen (N) fertilizer (20 kg/ha, urea) was applied to seedlings without inoculation, and uninoculated seedlings (without inoculation and without fertilization) served as control. The experiment was, therefore, a factorial arrangement (10 BGN accessions, 4 B. japonicum strains, N fertilizer application, and an uninoculated control). The yield and yield components of the inoculated BGN accessions were significantly enhanced at both agroecological locations and seasons. Among the B. japonicum strains used for inoculation, RACA6 strains significantly enhanced the yield and yield component of TVSu-1698 than other inoculated BGN accessions with a mean value of 6,234 ± 87 kg ha−1 recorded in both locations and seasons, compared to the result obtained in the combination of TVSu-1698 with N fertilizer with a mean value of 3,264 ± 943 kg ha−1. By using TVSu-1698 with RACA6 strain, farmers can get 85% more yield than on average with other genotypes/strains combination, while an average yield of 60% could be obtained by farmers using N fertilizer application.

Symbiotic effectiveness of Bradyrhizobium strains on soybean growth and productivity in Northern Mozambique

Inoculation of soybean [Glycine max(L.) Merr.] with rhizobia strains is a low-cost investment which can increase yields of smallholder farmers in Mozambique. The performance of fourBradyrhizobiumstrains was evaluated to identify the best strain to inoculate soybean grown in different agro-ecologies. Field experiments were conducted in three ecological zones in 2018 and 2019 using soybean variety Zamboane inoculated withBradyrhizobium diazoefficiensstrain USDA 110,B. japonicumstrains USDA 136, USDA 442 and WB74, and a non-inoculated control in a randomized complete block design with four replications. Indigenous rhizobia populations at the sites ranged from 9.0 x 101to 2.2 x 103cells g−1soil. All four strains increased nodulation, but USDA 110 was superior at two sites with low native rhizobia population, whereas USDA 442 and WB74 were the best at the site with relatively high native rhizobia population. On an average, the strains doubled the number of nodules and increased the dry weight up to 5.8-fold. Inoculation increased shoot dry weight and N content at podding, plant biomass, and number of pods plant−1across sites but the effects of the strains on seeds per pod, and 100-seed weight were inconsistent. Shoot N content did not differ among inoculant strains and ranged from 15.70 g kg−1in the control to 38.53 g kg−1across inoculation. All four strains increased soybean grain yield across sites in 2018 but USDA 110 outperformed the other strains and was also the best at one of the two sites in 2019. Grain yield responses associated with USDA 110 ranged from 552 kg ha−1(56%) to 1,255 kg ha−1(76%). Positive correlations between nodule dry weight plant−1and seed yield, and number of pods plant−1and grain yield were observed. The gross margin ranged from $343.50–$606.80 ha−1for the control, but it increased to $688.34–$789.36 when inoculants were applied. On an average, inoculation increased gross margin by $182.57-$395.35 ha−1over that of non-inoculated control in 2018 but drought stress in 2019 reduced the benefit. The results demonstrate that USDA 110 was the best inoculant strain and has the potential of increasing smallholder productivity and net returns.

The Role of Trehalose-producing Bradyrhizobium japonicum and Azotobacter chroococcum in Enhancing Salinity Tolerance of Zea mays Plants

Salinity is one of the most potent abiotic elements in nature and is damaging to both plants and microbes. Osmostress response in bacteria involves the accumulation of small organic compounds called compatible solutes as trehalose. In this work the synthesis and accumulation of trehalose by Bradyrhizobium japonicum strain (ARC 517) were investigated. Different sources of carbon, nitrogen, initial pH, and inoculum level were studied in order to increase trehalose productivity. An optimal production medium containing glucose and yeast extract was found suitable for trehalose production. The results showed that keeping the pH of the culture broth at 6.0 is important for trehalose production. Moreover the optimal level of inoculum was 4.0%. The optimized parameters gave a maximum trehalose production of 22.65 mg ml-1. Scanning electron microscope showed that cells of B. japonicum that enhanced for trehalose was aggregated and became the longest with length about 3 times higher than that of control. The results of field experiment revealed that, the Zea mays plants treated with B. japonicum strain (ARC 517) that enhanced for trehalose + Azotobacter chroococcum retained higher relative water content (RWC), chlorophyll content, K+/Na+ ratio as compared to other treatments. Positive correlation between trehalose overproduction and high-yield parameters were observed under saline conditions. These findings suggest that trehalose overproduction could be a beneficial characteristic for biofertilizers.

Soybean growing under inoculation by Bradyrhizobium japonicum strains in the Forest-steppe and Steppe zones of Ukraine

Soybean growing under inoculation by Bradyrhizobium japonicum strains in the Forest-steppe and Steppe zones of Ukraine

Symbiotic and physiological indicators of soybean inoculated of Bradyrhizobium japonicum single-strain in 7 days before sowing

Results of investigation of soybean of the Almaz variety in inoculation with preparations based on nodule bacteria Bradyrhizobium japonicum (Kirchner, 1896), Jordan, 1982 B78, B157, D37, D87 are presented. Different periods of the soybean seeds inoculation were used - on the sowing day (control) and in 7 days before sowing (experimental variants). The differences between control and experimental plants in the formation and functioning of the symbiotic apparatus and its functional activity, depending on the period between from seed inoculation to sowing were analysed. It was determined that the number of root nodules in the control plants was higher. The mass of nodules at the stage of 3 true leaves exceeded the control by 1.5–2.0 times in plants inoculated in 7 days before sowing, and the intensity of nitrogen fixation by 1.7–6.6 times. At the budding-beginning of flowering stage, the mass and intensity of N2 fixation by the nodules of control plants increased. As a result, the difference between the nitrogen fixing activity of control and experimental plants decreased significantly. Stimulating effect on aboveground mass of Bradyrhizobium japonicum strains with increased nitrogen fixing activity was noted. Optimal conditions for the formation and functioning of bean-rhizobial symbiosis were provided at the use of both of these terms of soybean inoculation. This reveals the possibility of effective application of early inoculation of soybean seeds with preparations based on nodule bacteria Bradyrhizobium japonicum active strains.

Effect of Bradyrhizobium japonicum Strains and Inorganic Nitrogen Fertilizer on the Growth and Yield of Bambara Groundnut (Vigna subterranea (L.) Verdc) Accessions

This study was set up to compare the inoculation of Bradyrhizobium japonicum strains and the application of nitrogen (N) fertilizers (urea with 46% nitrogen) on the growth and yield of Bambara groundnut accessions. The study results suggest that the benefits of Bradyrhizobium japonicum (B. japonicum) strain inoculation are greater and that the strain could reduce reliance and the excess amount spent by farmers to procure inorganic fertilizers and avoid the negative effect of N fertilizer on the environment after its use. Field studies were conducted in two different geographical locations, in Ibadan (Ib) and Ikenne (Ik), Nigeria, during the rainy season between August and December in 2019 and 2020. The experiment was arranged in a randomized complete block design (RCBD) in both locations and seasons and was replicated three times, with each block representing each replicate. It had a 10 × 6 factorial arrangement with one block holding the 10 accessions of Bambara groundnut inoculated with four B. japonicum strains. The second block had N fertilizer application and the third control block was without inoculation or fertilizer application. The 10 accessions of Bambara groundnut used in the study were as follows: TVSu-378, TVSu-506, TVSu-787, TVSu-1606, TVSu-1698, TVSu-1739, TVSu-710, TVSu-365, TVSu-475, and TVSu-305. Six seeds of each accession were coated with each of the four B. japonicum strains, namely, FA3, USDA110, IRJ2180A, and RACA6, before planting them in the field in both locations during the rainy season. In the next block, urea as N fertilizer (46% nitrogen) was applied to the uninoculated seedlings of accessions of Bambara groundnut 2 weeks after planting (WAP). The third block was the control with zero inoculation and zero fertilizer application. Data collected were subjected to an analysis of variance and mean and were separated using Duncan's Multiple Range Test (DMRT) at a p &amp;gt; 0.05 level of probability. It was found that FA3 inoculation significantly enhanced the growth traits of the accessions than other strains and N fertilizer application. In both locations and seasons, at 7 weeks after planting (WAP) and 12 WAP, plant height (19.54 and 22.71 cm), number of branches (33.63 and 62.77), number of leaves (116.54 and 209.25), terminal leaf length (5.62 and 6.00 cm), and width (2.09 and 2.56 cm) were recorded. The yield and yield components recorded at harvest were as follows: pod length (13.27 cm), pod width (9.08 mm), seed length (9.39 mm), seed width (6.92 mm), weight of 100 seeds (56.85 g), and yield/ha (750.72 kg). The yield and yield components were also significantly influenced by the inoculation of FA3 and RACA6 than other inoculated strains and N fertilizer application in both locations and seasons.

Revealing potential functions of hypothetical proteins induced by genistein in the symbiosis island of Bradyrhizobium japonicum commercial strain SEMIA 5079 (= CPAC 15).

BackgroundBradyrhizobium japonicum strain SEMIA 5079 (= CPAC 15) is a nitrogen-fixing symbiont of soybean broadly used in commercial inoculants in Brazil. Its genome has about 50% of hypothetical (HP) protein-coding genes, many in the symbiosis island, raising questions about their putative role on the biological nitrogen fixation (BNF) process. This study aimed to infer functional roles to 15 HP genes localized in the symbiosis island of SEMIA 5079, and to analyze their expression in the presence of a nod-gene inducer.ResultsA workflow of bioinformatics tools/databases was established and allowed the functional annotation of the HP genes. Most were enzymes, including transferases in the biosynthetic pathways of cobalamin, amino acids and secondary metabolites that may help in saprophytic ability and stress tolerance, and hydrolases, that may be important for competitiveness, plant infection, and stress tolerance. Putative roles for other enzymes and transporters identified are discussed. Some HP proteins were specific to the genus Bradyrhizobium, others to specific host legumes, and the analysis of orthologues helped to predict roles in BNF.ConclusionsAll 15 HP genes were induced by genistein and high induction was confirmed in five of them, suggesting major roles in the BNF process.Supplementary informationThe online version contains supplementary material available at 10.1186/s12866-022-02527-9.

Physiological characteristics of pure cultures of a white-colored truffle Tuber japonicum.

A white-colored truffle Tuber japonicum, indigenous to Japan, is an ascomycetous ectomycorrhizal fungus. To clarify the physiological characteristics of this fungus, we investigated the influence of culture medium, temperature, and sources of nitrogen (N) and carbon (C) on the growth of five strains. Tuber japonicum strains grew better on malt extract and modified Melin-Norkrans medium, and showed peak growth at 20 °C or 25 °C. This fungus utilized inorganic (NH4 + and NO3 -) and organic N sources (casamino acids, glutamine, peptone, urea, and yeast extract). Additionally, this fungus utilized various C sources, such as monosaccharide (arabinose, fructose, galactose, glucose, and mannose), disaccharide (maltose, sucrose, and trehalose), polysaccharide (dextrin and soluble starch), and sugar alcohol (mannitol). However, nutrient sources that promote growth and their effects on growth promotion widely varied among strains. This can result from the strain difference in enzyme activities involved in the assimilation and metabolism of these sources.

The Effect of Mineral N Fertilization and Bradyrhizobium japonicum Seed Inoculation on Productivity of Soybean (Glycine max (L.) Merrill)

Soybean yields can be considerably improved by inoculation with selected Bradyrhizobium japonicum strains and fertilization. The aim of this study was to assess the productivity of two soybean cultivars depending on the applied N mineral fertilizers and seed inoculation with B. japonicum. The study showed that on average, for both cultivars, the soybean yield was most favorably affected by the combined use of inoculation and nitrogen fertilization (increase in seed yield by 42%, protein yield by about 28%). The application of mineral nitrogen at the dose of 30 or 60 kg·ha−1 allowed the increase in the seed yield by about 17% and protein content by about 14% compared to the control. Inoculation of soybean seeds with B. japonicum increased the yield of soybeans by about 20%, proteins by about 10% compared to the control, and inoculation of Hi®Stick Soy favored a better yield than Nitragina. Inoculation of seeds with Nitragina or Hi®Stick Soy and fertilization with mineral nitrogen increased the content of protein and fiber in seeds of both soybean cultivars, as well as reduced the amount of ash and fat. The seeds of cv. Aldana had a higher amount of protein and ash than cv. Annushka, but a similar amount of fat and fiber.

Phenylalanine Ammonia-Lyase Enzyme Activity in the Symbiotic System Glycine max – Bradyrhizobium japonicum by Seed Inoculation Different in Activity and Virulation Strain and Treatment with Fungicides

Phenylalanine ammonia-lyase (PAL) is a key enzyme of the phenylpropanoid pathway and provides precursors for the synthesis of many secondary metabolites, which are necessary for the development and protection of plants from external factors of various natures, in particular plays an important role in the formation and development of their symbiosis with microorganisms. Aim. To study the activity of PAL in soybean plants in the early stages of legume-rhizobial symbiosis under the influence of seed inoculation with Bradyrhizobium japonicum strains with different symbiotic properties on the background of fungicide treatment. Methods. Microbiology (bacterial culture growing, seeds inoculation), physiological (pot experiment), biochemical (determining the PAL enzyme activity). Results. Inoculation of soybean seeds with active virulent rhizobia induces a significant decrease in PAL activity in the roots at the primordial leaf stage and a significant increase in its activity level at the first true leaf stage, compared to inactive symbiosis. At the stage of third true leaf, the activity of PAL increased more significantly in soybean root nodules formed by inactive rhizobia, compared to active symbiosis. However, at the stage of third true leaves, the activity of PAL in soybean root nodules formed by inactive rhizobia increased significantly compared to active symbiosis. The use of fungicides for pre-sowing treatment of soybean seeds induces changes in the level of PAL activity in roots and nodules, which do not affect the overall dynamics of enzyme activity in different effective symbiotic systems Glycine max - Bradyrhizobium japonicum. Conclusions. The activity of PAL in the roots and especially in the root nodules of soybeans in the early stage of plant development in the case of fungicides using and bacterization is primarily due to the action of the inoculation factor, and is determined by the symbiotic properties of rhizobia strains, in particular, their virulence and nitrogen fixation activity.