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Rhizobium is a Gram-negative bacterium, which dissolves minerals, produces growth hormones, promotes root growth, and protects plants from different soil-borne pathogens. In the present study, roots, stalks, and fresh weight of maize (Zea mays L.) were significantly increased after soaking in Bradyrhizobiumjaponicum compared with the control. Subsequently, transcriptome sequencing results of the whole maize plant soaked in B. japonicum showed that multiple growth and development-related genes were up-regulated more than 100-fold compared to the control. Furthermore, the abundance of plant growth promoting bacteria, such as Acidobacteria Subgroup_6 and Chloroflexi KD4-96, were increased significantly. On the contrary, the abundance of multiple pathogens, such as Curvularia, Fusarium and Mycocentrospora, were significantly decreased. Moreover, inoculation with B. japonicum could inhibit the infection of the pathogen Fusarium graminearum in maize. These results suggest that soaking seeds in B. japonicum may affect the expression of maize growth and development-related genes as the bacteria changes the soil microorganism community structure. These findings may help to expand the application of B. japonicum in crop production and provide new opportunities for food security.

s of the World Soybean Research Conference 11 (WSRC 11), 18-23 June 2023, Vienna, Austria. Published by: University of Natural Resources and Life Sciences, Vienna, Austria.

The objective of this work was to determine the effect of bioproducts on the growth and phytosanitary status of turnip plants, this with the main purpose of determining the viability in the use of ecological alternatives such as chitosan and inoculants made with strains of Bradyrhizobium japonicum, with a view to contribute to the implementation of more sustainable practices in turnip production. The present study took place at the “La Maria” campus of the Quevedo State Technical University, Los Rios province, Ecuador. The methodology that was used was a completely randomized design (dca), consisting of 6 treatments in triplicate; the treatments consisted of the application of: 1) Chitosan of high molecular weight, 2) Chitosan of low molecular weight; 3) B. japonicum; 4) B. japonicum + high molecular weight chitosan; 5) B. japonicum + Chitosan of low molecular weight and 6) control. The turnip seeds were soaked for 2 hours in each of the treatments before planting later, the treatments were applied at 10, 20 and 30 days. To see the differences between the treatments, the Tukey test was implemented (p≤ 0, 05). The results determined that the highest emergence rate of turnip seeds was those obtained embedded with the T5 treatment (Chitosan underweight + bacteria) with a record of 49, 45%. Regarding productive parameters such as: leaf length, plant height, root length and yield per hectare, the treatments that included the use of high molecular weight chitosan stood out, in the same way, it occurred during the evaluation of the state phytosanitary, demonstrating great efficiency in turnip production under the agroclimatic conditions present in the area.

Soybean is the most inoculant-consuming crop in the world, carrying strains belonging to the extremely related species Bradyrhizobium japonicum and Bradyrhizobium diazoefficiens. Currently, it is well known that B. japonicum has higher efficiency of soybean colonization than B. diazoefficiens, but the molecular mechanism underlying this differential symbiotic performance remains unclear. In the present study, genome resequencing of four spontaneous oxidative stress–resistant mutants derived from the commercial strain B. japonicum E109 combined with molecular and physiological studies allowed identifying an antioxidant cluster (BjAC) containing a transcriptional regulator (glxA) that controls the expression of a catalase (catA) and a phosphohydrolase (yfbR) related to the hydrolysis of hydrogen peroxide and oxidized nucleotides, respectively. Integrated synteny and phylogenetic analyses supported the fact that BjAC emergence in the B. japonicum lineage occurred after its divergence from the B. diazoefficiens lineage. The transformation of the model bacterium B. diazoefficiens USDA110 with BjAC from E109 significantly increased its ability to colonize soybean roots, experimentally recapitulating the beneficial effects of the occurrence of BjAC in B. japonicum. In addition, the glxA mutation significantly increased the nodulation competitiveness and plant growth–promoting efficiency of E109. Finally, the potential applications of these types of non-genetically modified mutant microbes in soybean production worldwide are discussed.

Insufficient water supply is one of the main factors that significantly reduce the activity of nitrogen fixation by legume-rhizobial symbiotic systems. That is why comprehensive research on aspects of their resistance to water stress and the search for scientifically substantiated ways to improve the existing ones and develop modern, competitive technologies of growing legumes in arid conditions are becoming especially relevant. The aim of the work was to investigate the processes of formation and functioning of soybean-rhizobial symbiotic systems developed under conditions of different water supply and influence of nanocarboxylates of cobalt, ferum, germanium, chromium, сuprum and molybdenum. The nanoparticles of specified metal nanocarboxylates were used as components of the inoculation suspension of rhizobia of Tn5 mutant B1-20 for soybean seed treatment. A model drought lasting 14 days was created by controlled irrigation. Microbiological and physiological research methods were used in the study. We determined that insufficient water supply caused a significant decrease in the nodulation potential of rhizobia and the intensity of molecular nitrogen fixation by symbiotic systems formed with the participation of soybean plants and nodule bacteria without adding these metal nanocarboxylates to the inoculation suspension. Application of most of the metal nanocarboxylates used as components of the inoculation suspension mitigated the negative impact of stress on the investigated parameters. The study revealed the stimulating effect of cobaltnanocarboxylate on the activity of molecular nitrogen fixation, which was more pronounced in the conditions of insufficient water supply. Symbiotic soybean systems formed with the participation of nodule bacteria containing germaniumcarboxylate nanoparticles were proved to be the least sensitive to the negative impact of insufficient water supply. This was indicated by high rates of nodulation and nitrogen-fixing activity compared with other studied symbiotic systems. We confirmed that the addition of chromium nanocarboxylate to the inoculation suspension of rhizobia provided the highest rates of nodulation and nitrogen-fixing activity of soybean root nodules under optimal growing conditions and, at the same time, had no noticeable positive effect under water stress. We determined that сuprum and molybdenum nanocarboxylates, as components of the inoculation suspension, regardless of the water supply level, had a less notable positive effect on the processes of nodule formation and nitrogen fixation, and in some cases even led to a decrease in the investigated values for control plants. Thus, the study demonstrated that the use of germanium, cobalt and ferum nanocarboxylates as components of the bacterial suspension helped to increase the adaptation of the formed legume-rhizobial symbiotic systems to water stress, as evidenced by the maximum indexes of nodulation and molecular nitrogen fixation in the context of insufficient water supply and recovery of their level to optimal after the stress influence had ended. Based on the results, it was concluded that inoculation of seeds by the complex bacterial preparations made on the basis of Bradyrhizobium japonicum B1-20 with a content of germanium, cobalt and ferum nanocarboxylates in the concentration of 1:1000 can become one of the important means in soybean growing technologies of increasing the nitrogen-fixing potential and resistance of plants to insufficient water supply.

Numerous studies reported the positive effect of soil amendment with biochar on plant development. However, little is known about biochar and its interrelation with nitrogen (N) and phosphorous (P) additions and their impact on plant growth. We carried out greenhouse experiments to understand the interactive effects of nitrogen and phosphorus supply, as well as biochar amendment, on the symbiotic performance of soybean (Glycine max L.) with Bradyrhizobium japonicum, and plant growth and nutrient uptake. The biochar was produced from maize by heating at 600 °C for 30 min and used for pot experiments at an application rate of 2%. Plants were fertilized with two different concentrations of P (KH2PO4) and N (NH4NO3). Biochar application significantly increased the dry weight of soybean root and shoot biomass, by 34% and 42%, under low nitrogen and low phosphorus supply, respectively. Bradyrhizobium japonicum inoculation enhanced the dry weight of shoot biomass significantly, by 41% and 67%, in soil without biochar and with biochar addition, respectively. The nodule number was 19% higher in plants grown under low N combined with low or high P, than in high N combinations, while biochar application increased nodule number in roots. Moreover, biochar application increased N uptake of plants in all soil treatments with N or P supply, compared with B. japonicum-inoculated and uninoculated plants. A statistical difference in P uptake of plants between biochar and nutrient levels was observed with low N and high P supply in the soil. Our results show that the interactions between nitrogen, phosphorus, and biochar affect soybean growth by improving the symbiotic performance of B. japonicum and the growth and nutrition of soybean. We observed strong positive correlations between plant shoot biomass, root biomass, and N and P uptake. These data indicated that the combined use of biochar and low N, P application can be an effective approach in improving soybean growth with minimum nutrient input.

Field experiments were conducted during the four crop seasons 2013 through 2015 on Bradyrhizobium japonicum inoculation of wheat, soybean or double inoculation of both crops under fertilization or not with NPK. Inoculation of wheat with B. japonicum gave 21 and 18% increase in grain yield and plant N uptake under fertilization regime. Pre-inoculation of wheat resulted in 23% higher nodule numbers in soybean; however, the soybean seed yield and plant N content increases were non-significant. Inoculation of only soybean increased the nodule numbers, seed yield and N content in fertilized soybean by 43, 11 and 16%, respectively; double inoculation increased it by 53, 17 and 22%. Averaged over inoculation treatments and fertilization regimes, the rhizobial numbers in soybean were 2.0× of those in wheat. The effects of chemical fertilization stimulated the rhizobial populations 2.1× over non-fertilized. Averaged over all 10-stages and both fertilization regimes, the rhizobial populations in soybean rhizosphere increased 1.8× by pre-inoculating wheat; 3.0× by inoculating only soybean and 4.3× by double inoculation over uninoculated. Overall, the symbiotic performance was: Double inoculation > Soybean inoculation > Wheat inoculation > Uninoculated. Application of Bradyhizobium inoculants to both soybean and wheat was beneficial to maximize rhizobial numbers, soybean nodulation, crop and N yield of soybean and wheat, and buildup soil organic matter and nitrogen. The additional N content in soybean and wheat by double inoculation over single soybean inoculation was ~ 40 kg N ha−1.

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.

Proline utilization A (PutA) from Bradyrhizobium japonicum (BjPutA) is a bifunctional avoenzyme that catalyzes the oxidation of proline to glutamate using fused proline dehydrogenase (PRODH) and ∆1-pyrroline-5-carboxylate dehydrogenase (P5CDH) domains. Recent crystal structures and kinetic data suggest an intramolecular channel connects the two active sites, promoting substrate channeling of the intermediate P5C from the PRODH domain to the P5CDH domain. In this work several mutations were made along the channel in an effort to block passage of P5C to the second active site. Analysis of several site-specic mutants in the substrate channel of BjPutA revealed an important role for D779 in the channeling path. BjPutA mutants D779Y and D779W signicantly decreased the overall PRODH-P5CDH channeling reaction indicating that bulky mutations at residue D779 impede travel of P5C through the channel. Interestingly, D779Y and D779W also exhibited lower P5CDH activity, suggesting that exogenous P5C must enter the channel upstream of D779. Replacing D779 with a smaller residue (D779A) had no effect on the catalytic and channeling properties of BjPutA showing that the carboxylate group of D779 is not essential for channeling. An identical mutation at D778 (D778Y) did not impact BjPutA channeling activity. Thus, D779 is optimally orientated so that replacement with the larger side chains of Tyr/Trp blocks P5C movment through the channel. The kinetic data reveal not only that bulky mutations at residue D779 hinder passage of P5C to the second active site, but also P5C must use the channel to efciently access the P5CDH domain. Moreover, these mutants may be used to learn more about the hydrolysis event that is thought to take place within the channel

The ability for a soybean plant to be efficiently nodulated when grown as a crop is dependent on the number of effective Bradyrhizobium japonicum that can be found in close proximity to the developing seedling shortly after planting. In Manitoba, the growing of soybean as a crop has increased from less than 500 000 acres in 2008 to over 2.3 million acres in 2017. Since the large increase in soybean production is relatively recent, populations of B. japonicum have not yet developed. In response to this, we developed a primer pair that can identify B. japonicum, and be used to determine the titre found in field soil. Their utility was demonstrated by being used to determine whether row spacing of soybean affects B. japonicum populations, as well as to follow B. japonicum populations in a soybean field over the course of a field season. The data show that plant density can affect B. japonicum populations. Moreover, evidence is presented that suggests plant development affects overall B. japonicum populations.

Objetivo desse trabalho foi avaliar o desempenho da soja em nodulação e crescimento radicular sob diferentes níveis de dosagem em inoculação e coinoculação. Foi conduzido em Delineamento em blocos casualizados, em esquema fatorial 4x16. As dosagens utilizadas foram 50-100-150ml (25kg de semente) com Azospirillum brasilense e 450-900-1350ml por ha de Bradyrhizobium japonicum. Os resultados das análises da parte aérea e radicular das plantas foram comparados pelo teste de Tukey (significância de 5%). A inoculação com Bradyrhizobium japonicum apresentou resultados superiores em todos os aspectos avaliados quando comparadas a o tratamento zero, já a inoculação com Azospirillum brasilense não demonstrou resultados significativos em nenhum aspecto isoladamente. Com a co-inoculação mostrou que a interação das duas estirpes apresentou resultado superior, na matéria verde raiz e matéria seca parte aérea, significando um melhor desenvolvimento vegetativo da planta

Resumen Las PGPB por sus siglas en inglés son bacterias benéficas para el crecimiento de plantas, por lo anterior se han desarrollado inoculantes con estas bacterias y han dado buenos resultados en plantas de interés agrícola como el maíz, arroz, soja entre otras [1, 2]. Sin embargo, el desempeño de éstas puede ser afectado por diferentes factores, cuando las PGPB son inoculadas en las semillas mueren rápidamente y aún más después de la plantación. El principal motivo por el que las especies bacterianas no sobreviven es la disponibilidad de agua, si ésta no es suficiente, las células entran al proceso de desecación; caracterizada como la perdida de agua intracelular, esto supone estrés para la bacteria y provoca daños, como el mal plegamiento y agregación de proteínas, así como daños en la membrana. En el trabajo que se discute en esta ponencia se propuso utilizar a la trehalosa para mejorar la tolerancia a desecación de Bradyrhizobium japonicum. La trehalosa es un disacárido no reductor, ésta se encuentra en altas concentraciones en organismos y microorganismos anhidrobiotes, es decir, aquellos altamente tolerantes a la desecación. La trehalosa previene la agregación de proteínas de membrana y citoplasmáticas preservando así la estructura global celular [3]. Se evaluó la concentración de trehalosa en la célula en diferentes condiciones de cultivo, así como la supervivencia de B. japonicum al ser inoculado en semillas de soja, y al enfrentarse al proceso de desecación, se obtuvo un incremento en las Unidades Formadoras de Colonia iniciales, la supervivencia fue aún mayor cuando se adicionó trehalosa al medio de cultivo. Por otro lado, se evaluó la concentración de trehalosa intracelular y ésta se correlacionó con la supervivencia, observando que la trehalosa citoplasmática estabiliza la membrana durante la desecación [4]. Para el medio al que se le adicionó extracto de levadura con una cantidad importante de trehalosa también se mejoró la supervivencia bacteriana, por lo tanto, la síntesis y acumulación de trehalosa intracelular es esencial para la supervivencia de B. japonicum durante la desecación [5]., {"references":["Danish S, Zafar-Ul-Hye M, Mohsin F, Hussain M. ACC-deaminase producing plant growth promoting rhizobacteria and biochar mitigate adverse effects of drought stress on maize growth. PLoS One. 2020 Apr 6;15(4):e0230615. doi: 10.1371/journal.pone.0230615. Erratum in: PLoS One. 2021 Apr 12;16(4):e0250286. PMID: 32251430; PMCID: PMC7135286.","Ngalimat MS, Mohd Hata E, Zulperi D, Ismail SI, Ismail MR, Mohd Zainudin NAI, Saidi NB, Yusof MT. Plant Growth-Promoting Bacteria as an Emerging Tool to Manage Bacterial Rice Pathogens. Microorganisms. 2021 Mar 26;9(4):682. doi: 10.3390/microorganisms9040682. PMID: 33810209; PMCID: PMC8065915.","Koshland D, Tapia H. Desiccation tolerance: an unusual window into stress biology. Mol Biol Cell. 2019 Mar 15;30(6):737-741. doi: 10.1091/mbc.E17-04-0257. PMID: 30870092; PMCID: PMC6589773.","Leslie SB, Israeli E, Lighthart B, Crowe JH, Crowe LM. Trehalose and sucrose protect both membranes and proteins in intact bacteria during drying. Appl Environ Microbiol. 1995 Oct;61(10):3592-7. doi: 10.1128/aem.61.10.3592-3597.1995. PMID: 7486995; PMCID: PMC167656.","Streeter JG. Effect of trehalose on survival of Bradyrhizobium japonicum during desiccation. J Appl Microbiol. 2003;95(3):484-91. doi: 10.1046/j.1365-2672.2003.02017.x. PMID: 12911696."]}

Background. Global soybean production is expected to double in the coming decades, driven by a request for animal feed to meet increasing meat consumption. Demand for locally produced food and feed is also increasing, making it interesting to explore the potential for soybean production in high-latitude regions. Scope. To present information on the potential for cultivating vegetable soybean, edamame, under cold-temperate conditions. Conclusions. For the successful establishment, sowing at low soil temperatures should be avoided. Commercial inoculants are effective, irrespective of soybean cultivar. There is no need to re-inoculate fields if the crop has been included in the crop rotation. Little nitrogen remains in the soil after harvest, resulting in a low risk of leaching but a need for nitrogen fertilisation of the following crop. Suitable vegetable soybean cultivars are available on the market and are preferred compared to cultivars intended for dry harvest. The cropping system needs to be improved, e.g. by moderating the microclimate by plastic tunnels, in order to secure harvest.

Nitrogen deficiency is a limiting factor in increasing efficiency of crop production in terrestrial ecosystems, and the transformation of inert nitrogen to forms that can be assimilated by plants is mediated by soil microorganisms. Symbiotic nitrogen-fixing bacteria and roots depend on each other and have developed various mechanisms for symbiotic coexistence. The aim of this work was to investigate the role of nitrogen deficiency on growth and development near isogenic by E genes lines of soybean (Glycine max (L.) Merr.): short-day (SD) line with genotype Е1е2е3(Е4е5Е7), and photoperiodic insensitive (PPI) line with genotype е1е2е3(Е4е5Е7) grown from seeds inoculated with active strains of Bradyrhizobium japonicum against the background of local populations of diazotrophs of the genus Azotobacter spp. and establish how the soybean – Bradyrhizobium symbiosis will develop as the genes of both microsymbionts and macrosymbionts are responsible for the formation of the symbiotic complex. Plants were grown in a vegetation chamber, in sand culture. To assess the quantitative composition of microorganisms in the rhizosphere and rhizoplanes, 6 plants were selected from each soybean line, then separation of the zones of the rhizosphere and rhizoplanes was performed using the method of washing and the resulting suspension was used for inoculation on dense nutrient media (mannitol-yeast agar medium and Ashby medium). The results of study showed that seed inoculation and co-inoculation provides faster formation of the symbiotic soybean – Bradyrhizobium complex. Differences in nodulation rates between the short-day line with genotype Е1е2е3(Е4е5Е7), and a photoperiodic insensitive line with genotype е1е2е3(Е4е5Е7) were identified. Determination of the amount of B. japonicum on the medium of mannitol-yeast agar in the rhizosphere and rhizoplane showed that inoculation by B. japonicum strain 634b caused a significant increase in the amount B. japonicum in the rhizosphere and rhizoplane in both soybean lines, comparison with non-inoculated seeds. Then, co-inoculation by B. japonicum strain 634b + Azotobacter chroococcum significantly increased the amount of B. japonicum only in the rhizoplane and decreased their number in the rhizosphere. Determination of the amount of A. chroococcum on the Ashby elective medium in the rhizosphere and rhizoplane showed that the inoculation by B. japonicum strain 634b caused a significant decrease in the amount of A. chroococcum both in the rhizosphere and in the rhizoplane of the PPI line of soybean, and in the rhizosphere the SD line, in comparison with non-inoculated seeds. That can testify to the competitive interaction of these microorganisms. However, the co-inoculation by B. japonicum strain 634b + A. chroococcum in the SD line significantly increased the number of A. chroococcum in the rhizoplane and decreased their number in the rhizosphere, in the PPI line their number decreased in the rhizoplane and increased in the rhizosphere, in comparison with non-inoculated seeds. Probably, the E genes (their dominant or recessive state) of soybean isogenic lines affect the regulation of the content and distribution of sugars. It was established that the nitrogen deficiency stimulated development of the root system of plants and the synthesized sugars were distributed predominantly to the root system growth. We suppose that the seeds’ inoculation had extended sugar consumption to the symbiont, due to which it compensates the lack of nitrogen, but leads to a slower growth of the root system.

N-phenyl-2-naphthylamine (N-PNA) and phthalates are classified as antibiotic substances. The appearance and accumulation of these substances in the biosphere is associated with their technogenic and biogenic origin (metabolites of plants and bacteria). In this article, we compare the degrading action of such soil bacteria as Rhizobium leguminosarum bv. viceae, Bradyrhizobium japonicum, Pseudomonas syringae pv. pisi, Clavibacter michiganensis sps. Sepedonicus and Azotobacter chroococcum against N-PNA. These bacteria differ in their interaction with pea plants (Pisum sativum L.) synthesising N-PNA. The degradation products were studied using gas chromatography-mass spectrometry in ethyl acetate extracts obtained from culture liquid media, in which N-PNA at a concentration of 10 μM and the bacteria under study were introduced. The decrease in the N-PNA concentration in the extracts obtained using ethyl acetate from culture media, in which N-PNA had been added to a concentration of 100 μM, was monitored following two days of bacterial growth using the methods of high-performance liquid chromatography. It was shown that all the studied bacterial species are capable of degrading N-PNA with the formation of phthalates. The Rhizobium bacteria, endosymbionts of pea plants synthesising N-PNA, and free-living nitrogen-fixing bacteria of the Azotobacter genus showed the highest degrading activity. It was found that N-PNA reduced the viability of all types of bacteria, although to a varying degree. N-PNA had the most negative effect on the viability of the Azotobacter genus, although these bacteria showed a high degrading action against N-PNA. The dependence between the negative effect of NPNA on bacterial viability and the N-PNA concentration was mildly pronounced for Rhizobium and Pseudomonas, although being significant for Bradyrhizobium and Clavibacter.

Background The present study aims to study the effects of biofertilizers potential of Arbuscular Mycorrhizal Fungi (AMF) and Bradyrhizobium japonicum (B. japonicum) strains on yield and growth of drought stressed soybean (Giza 111) plants at early pod stage (50 days from sowing, R3) and seed development stage (90 days from sowing, R5). Results Highest plant biomass, leaf chlorophyll content, nodulation, and grain yield were observed in the unstressed plants as compared with water stressed-plants at R3 and R5 stages. At soil rhizosphere level, AMF and B. japonicum treatments improved bacterial counts and the activities of the enzymes (dehydrogenase and phosphatase) under well-watered and drought stress conditions. Irrespective of the drought effects, AMF and B. japonicum treatments improved the growth and yield of soybean under both drought (restrained irrigation) and adequately-watered conditions as compared with untreated plants. The current study revealed that AMF and B. japonicum improved catalase (CAT) and peroxidase (POD) in the seeds, and a reverse trend was observed in case of malonaldehyde (MDA) and proline under drought stress. The relative expression of the CAT and POD genes was up-regulated by the application of biofertilizers treatments under drought stress condition. Interestingly a reverse trend was observed in the case of the relative expression of the genes involved in the proline metabolism such as P5CS, P5CR, PDH, and P5CDH under the same conditions. The present study suggests that biofertilizers diminished the inhibitory effect of drought stress on cell development and resulted in a shorter time for DNA accumulation and the cycle of cell division. There were notable changes in the activities of enzymes involved in the secondary metabolism and expression levels of GmSPS1, GmSuSy, and GmC-INV in the plants treated with biofertilizers and exposed to the drought stress at both R3 and R5 stages. These changes in the activities of secondary metabolism and their transcriptional levels caused by biofertilizers may contribute to increasing soybean tolerance to drought stress. Conclusions The results of this study suggest that application of biofertilizers to soybean plants is a promising approach to alleviate drought stress effects on growth performance of soybean plants. The integrated application of biofertilizers may help to obtain improved resilience of the agro ecosystems to adverse impacts of climate change and help to improve soil fertility and plant growth under drought stress.

The phenotypic and genotypic features of soybean nodule bacteria with different growth rates common in soils of Ukraine have been studied. The obtained results suggest high heterogeneity of soybean microsymbionts. It has been established that all studied strains are able to form active symbiotic relationships with soybean. When interacting with Chinese cowpea, intensive-growing strains form an ineffective symbiosis with a low nitrogen fixation level (phenotype Nod+Fix–), while slow-growing strains form complete nitrogen fixing systems (phenotype Nod+Fix+). Upon cultivation in the mannitol yeast medium, intensive-growing strain B. japonicum KC19 produces a significant amount of auxins and cytokinins, while the slow-growing strain B. japonicum KC23 is significantly superior by the amount of gibberellins. According to the organization of the genome defined in REP-PCR, studied strains of soybean rhizobia belong to two genetic groups, which corresponds to the division of strains into groups by the growth rate (slow- and intensive-growing). Based on the RFLP analysis of rpoB gene, using restriction enzymes MspI, HaeIII and NdeII, intensive-growing strains were combined into one rpoB type, while slow-growing strains belong to 2-3 rpoB types.

Soybean is one of the most profitable advanced crops in agricultural production in Ukraine and the world as a whole. Therefore, studies of means of regulation and increase in the adaptive capacity of soybeans in symbiosis with nodule bacteria under the action of unfavourable environmental factors are relevant and should be aimed at the use of complex bacterial compositions involving modern nanotechnological approaches. Nanocarboxylates of ferrum, molybdenum and germanium metals were used as components of rhizobia inoculation suspension for soybean seed treatment to study the effectiveness of their complex effect on the regulation of the activity of the key antioxidant enzyme superoxide dismutase in plants under drought. Various symbiotic systems were used, which included soybean plants and inoculation suspensions based on the active, virulent Tn5-mutant Bradyrhizobium japonicum B1-20 by adding nanoparticles of ferrum, germanium and molybdenum carboxylates to the culture medium in a ratio of 1: 1000. Citric acid was the chelator. A model drought lasting 14 days was created during the period of active fixation of atmospheric molecular nitrogen by root nodules of soybeans in the budding and flowering stages, by means of controlled watering of plants to 30% of the total moisture content. In the stage of bean formation, watering of plants was resumed to the optimal level – 60% of the total moisture content. The control was soybean plants, the seeds of which were inoculated with a suspension of rhizobia without the addition of chelated metals. The following research methods were used in the work – microbiological, physiological and biochemical. According to the results, it was found that when nanoparticles of carboxylates of ferrum, molybdenum and germanium were added to the inoculation suspension of rhizobia, there was an increase in superoxide dismutase activity in root nodules and a decrease in soybean leaves under optimal water supply conditions of plants. This indicates the initial changes in the activity of the antioxidant enzyme in these symbiotic systems, induced by the influence of chelated metals in combination with the rhizobia of the active Tn5-mutant B. japonicum B1-20. Prolonged drought induced an increase in the overall level of superoxide dismutase activity in soybean nodules and leaves, compared to plants grown under optimal watering conditions. The symbiotic system formed by soybeans and B. japonicum with molybdenum carboxylate nanoparticles was the most sensitive to long-term drought exposure, compared to two other soybean-rhizobial symbioses using ferrum and germanium nanocarboxylates. This was manifested in the unstable reaction of the enzyme to the action of drought – suppression or intensification of the level of its activity in the root nodules and leaves of soybeans inoculated with rhizobia containing molybdenum carboxylate nanoparticles. In symbiotic systems with the participation of germanium and ferrum nanocarboxylates, slight changes were revealed in superoxide dismutase activity in root nodules and leaves of plants during drought and restoration of enzyme activity to the level of plants with optimal watering after water stress. It is concluded that the addition to the culture medium of rhizobia Tn5-mutant B1-20 of nanocarboxylates of germanium or ferrum is an effective means of regulating the activity of the antioxidant enzyme superoxide dismutase in soybean root nodules and leaves, which can contribute to an increase in the protective properties and adaptation of plants to the action of dehydration.

O emprego de produtos biológicos no sistema de plantio direto constitui-se uma prática sustentável e com menor potencial poluente que o uso de produtos químicos. Nesta pesquisa objetivou-se avaliar o desempenho agronômico de três cultivares de soja após a inoculação pós emergente de biológicos no solo. O delineamento experimental utilizado foi o de blocos casualizados em esquema em parcelas subdivididas 3×5, com três repetições. Os tratamentos foram a combinação de três cultivares (BRASMAX-FOCO-IPRO, BRASMAX-DESAFIO-IPRO e BRASMAX-BÔNUS-IPRO) e quatro biológicos [Azospirillum brasilense + Bradyrhizobium japonicum (1), BioAx (2), Trichoderma asperrellum (3), 1+2+3 (4)], mais um Controle (ausência de biológicos) (5). Foi avaliado a altura das plantas (AP), inserção do primeiro legume (IPL), número de legume por planta (PNL), número de grãos por legumes (NGL), massa de mil grãos (MMG) e produtividade (PROD). Os grãos colhidos, foram classificados por tamanho em peneiras de diâmetros de 7.5, 7.0, 6.5, 6.0, 5.5, 5.0 e 4.5 mm. A porcentagem de grãos retidos (RP) e a produtividade relativa de grãos retidos nas peneiras (PRGRP) foi calculada. Os resultados apontaram interações significativas (p

A planta de soja tem a associação simbiôntica com micro-organismos que têm a capacidade de fixar nitrogênio (N) e liberá-lo para as plantas. Nas cultivares de soja de alto potencial produtivo, a demanda por N estaria sendo atendida através da fixação biológica de nutrientes (FBN) ou haveria a necessidade de complementação deste nutriente para a cultura. Este trabalho teve como objetivo verificar a resposta da cultivar de soja Desafio inoculada com bactérias Bradyrhizobium japonicum e Bradyrhizobium elkanii, e com adubação nitrogenada suplementar na fase reprodutiva, via solo e via foliar. Os tratamentos constituíram da testemunha (sem aplicação de N), 30 e 60 kg de N ha-1 via solo e solução a 2% de N aplicados nas fases R1 e R5.3. O delineamento foi de blocos casualizados com quatro repetições e as sementes foram inoculadas com bactérias das espécies Bradyrhizobium japonicum e Bradyrhizobium elkanii (estirpes Semia 587 e Semia 5019). A aplicação tardia de N em R1 e em R5.3 proporcionou aumento na produtividade de grãos de 478,6 kg ha-1 e 472,8 kg ha-1, respectivamente. A aplicação via solo de N em R1 apresenta melhor índice de colheita, quando comparada com a R5.3. A aplicação tardia de solução de 2% de N, via foliar, não proporciona aumento na produtividade da cultura da soja. Palavras-chave: Glycine max. Produtividade. Fixação Biológica. Adubação Nitrogenada. Abstract The soybean plant has the symbiotic association with microorganisms that has the ability to fix nitrogen (N) and release it to the plants. Soybean cultivars with high productive potential, N demand would be met through biological nutrient fixation (BNF) or there would be a need to complement this nutrient for the crop. The objective of this work was to verify the response of soybean inoculated with bacteria of the genus Rhizobium and Bradyrhizobium, the supplementary nitrogen fertilization in the reproductive phase, soil and leaf pathway. The treatments consisted of control (without application of N), 30 and 60 kg of N ha-1 via soil and 2 % N solution applied in phases R1 and R5.3. The design was randomized blocks with 4 replications and the seeds were inoculated with bacteria of the species Bradyrhizobium japonicum and Bradyrhizobium elkanii (strains Semia 587 and Semia 5019). The late application of N in R1 and R5.3 increased grain yield of 478.6 kg ha-1 and 472.8 kg ha-1, respectively. The application, via soil, of N in R1 presents a better harvest index, when compared to R5.3. The late application of 2% N solution, via leaf, did not increase the soybean crop yield Keywords: Glycine max. Productivity. Biological Fixation. Nitrogen Fertilization

Soil amendment with beneficial microorganisms is gaining popularity among farmers to alleviate the decline of soil fertility and to increase food production and maintain environmental quality. However, farm management greatly influence soil microbial abundance and function, which overly affects crop growth and development. In this work, greenhouse experiments involving soybeans were conducted to evaluate the effects of bradyrhizobia and arbuscular mycorrhizal fungi (AMF) dual inoculation on nodulation, AMF root colonization, growth and nutrient acquisition under contrasting farming systems. The experimental treatments were AMF and/or bradyrhizobia inoculation and dual inoculation on SC squire soybean variety. The exotic AMF inoculants used were Funneliformis mosseae (BEG 12) and Rhizophagus irregularis (BEG 44) while bacteria were commercial Bradyrhizobium japonicum (USDA110) and native bradyrhizobia isolates. Experiments with soil samples from organic and conventional farms were set out using a completely randomized design with three replicates. The results demonstrated that bradyrhizobia and AMF dual inoculation consistently and significantly enhanced soybean nodule dry weight (NDW), shoot dry weight (SDW) and AMF root colonization compared with individual bradyrhizobia , AMF and non-inoculated control. Moreover, organic soil significantly (p = 0.001) increased soybean SDW, NDW and AMF root colonization compared to conventional soil. Remarkably, shoot nutrients content differed in organic and conventional farming where, shoot nitrogen, phosphorus, potassium and organic carbon were higher in organic farming than the latter. Among individual inoculants, Rhizophagus irregularis out-performed Funneliformis mosseae, while commercial Bradyrhizobium japonicum showed higher performance than native bradyrhizobia. Our results demonstrated the importance of organic farming, AMF and bradyrhizobia dual inoculation in enhancing soybean growth and nutrient acquisition. However, field trials should be assessed to determine the good performance of bradyrhizobia and AMF dual inoculation in organic farming before being popularized and adopted by farmers as a sustainable agronomical management strategy to increase soil fertility and food productivity.

Introducao: O crescente rendimento agricola da soja exige adocao tecnologica em insumos, manejos, equipamentos e zoneamentos agricolas equilibrados aos fatores economicos de producao. Reduzir dependencia por insumos quimicos importados e promover uso adequado por adubacao de cama de aves, determina o fator de custo de producao, por demonstrar atributos de fertilidade do solo maiores que a mineral. Metodologia: A estrategia de pesquisa foi verificar os impactos das doses de cama de aves sobre rendimento da cultura da soja numa variedade super precoce. Experimento conduzido na safra 2018/2019 no municipio Chapeco. O delineamento de tratamentos e um arranjo em faixas com 9 tratamentos e 3 repeticoes sobre diferentes doses de cama de aves e inoculacao Bradyrhizobium japonicum em avaliacoes nas fases fenologicas V3 e R1, em analise de variância teste F e as medias comparadas pelo teste de Tukey (P≤0,05). Resultados e discussoes: Fator variavel resposta nao diferiu estatisticamente entre numero de nodulos ativos e totais. Nodulos inativos apresentam diferencas estatisticas entre tratamentos e sobre fases fenologicas. A apreciacao NDVI mostra diferencas estatisticas na fase fenologica V3. O tratamento com 60% da dose recomendada reduziu o rendimento por hectare consideravelmente comparado a 40% da dose de cama de aves. A utilizacao do inoculante como variavel resposta nao aferiu efeito quando comparado as diferentes doses de cama de aves. O peso de mil graos tem relacao direta ao indice de rendimento. Conclusao: Os resultados demonstram altos rendimentos e valores economicos lucrativos R$/ha, igualmente positiva na utilizacao de 40% mais a dose recomendada de cama de aves.

In the framework of the comprehensive research of Far Eastern natural populations of soybean nodule bacteria, laboratory experiments have been conducted at the All-Russia Scientific Research Institute of Soybean (Blagoveshchensk) with the purpose to identify distinctive features of rhizobia species Sinorhizobium fredii (Scholla and Elkan, 1984) and Bradyrhizobium japonicum (Jordan, 1982) whose pure cultures were isolated from soils of Far Eastern regions practicing soybean cultivation. It is established that B. japonicum strains start growing in Petri dishes on the seventh to tenth and even on the 20th day after the inoculation, assimilate a limited number of carbon nutrition sources, release mostly alkaline metabolic products, and feature a relatively low osmotic resistance. Representatives of this species are susceptible to extreme environmental conditions; their growth sharply slows down on acidic and alkaline nutrient media and stops at high (37–42°C) temperatures. However, under the optimal conditions, this rhizobia species dominates in the nodulation of soybean plants due to its high and persistent virulence. The restriction analysis of the studied B. japonicum strains confirmed their identity. S. fredii strains start growing in Petri dishes on the second to fourth day after the inoculation, assimilate well a broad spectrum of carbon nutrition sources, and release acidic metabolic products. Most strains of this species feature high osmotic resistance. Cultures retaining universal growth capacity under extreme environmental conditions (high temperatures and low and high pH values) have been identified in the group of S. fredii strains. This rhizobia species can predominate in the formation of symbiotic mechanisms in years featuring extreme weather conditions. Enzymatic fermentation of gene 16S rRNA in the studied S. fredii strains was performed using restriction enzyme HaeIII; the analysis of the fermentation results confirmed the identity of these strains. The RAPD-PCR analysis has demonstrated the intraspecific specificity of the studied B. japonicum and S. fredii strains: these species feature high degrees of polymorphism reflecting their population heterogeneity.

The cascading effects of microbe–plant symbioses on the second trophic level, such as phytophagous insects, have been most studied. However, few studies have examined the higher third trophic level, i.e., their natural enemies. We investigated the effects of the symbiotic associations between an arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis (Glomerales: Glomeraceae), a nitrogen-fixing bacterium, Bradyrhizobium japonicum (Rhizobiales: Bradyrhizobiaceae), and soybean, Glycine max (L.) Merr. (Fabaceae) on two natural enemies of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), the ladybird beetle Coleomegilla maculata (De Geer) (Coleoptera: Coccinellidae), and the parasitoid Aphelinus certus Yasnosh (Hymenoptera: Aphelinidae). We measured the growth and survival in the predator and parasitoid reared on aphids feeding on soybean inoculated seedlings. The rhizobium symbiosis alone was affected with a decreased rate of parasitoid emergence, presumably due to decreased host quality. However, number of mummies, sex-ratio, development time, and parasitoid size were all unaffected by inoculation. AM fungus alone or co-inoculated with the rhizobium was unaffected with any of the parameters of the parasitoid. For the predator, none of the measured parameters was affected with any inoculant. Here, it appears that whatever benefits the microbe–plant symbioses confer on the second trophic level are little transferred up to the third.

The inoculation of arbuscular mycorrhizal (AM) fungi and rhizobia in legumes has been proven to increase plant growth and yield. To date, studies of the effects of these interactions on phytophagous insects have shown them to be context-dependent depending on the inoculant strain, the plant, and the insect species. Here, we document how a symbiosis involving an AM fungus, Rhizophagus irregularis; a rhizobium, Bradyrhizobium japonicum; and soybean, Glycine max, influences the soybean aphid, Aphis glycines. Soybean co-inoculated with the AM fungus–rhizobium pair increased the plant’s biomass, nodulation, mycorrhizal colonization, nitrogen, and carbon concentrations, but decreased phosphorus concentration. Similar effects were observed with rhizobium alone, with the exception that root biomass was unaffected. With AM fungus alone, we only observed an increase in mycorrhizal colonization and phosphorus concentration. The aphids experienced an increased reproductive rate with the double inoculation, followed by rhizobium alone, whereas no effect was observed with the AM fungus. The size of individual aphids was not affected. Furthermore, we found positive correlation between nitrogen concentration and aphid population density. Our results confirm that co-inoculation of two symbionts can enhance both plant and phytophagous insect performance beyond what either symbiont can contribute alone.

The production of ethylene by soybeans symbiotic systems associated with different Bradyrhizobium strains during the treatment of seeds with fludioxanil (fungicide) and exposure to drought was studied. It was found that the intensity of ethylene release by soybean plants during pre-sowing fungicide seed treatment and insufficient water supply primarily depends on the genetic characteristics and symbiotic properties of the of Bradyrhizobium strain. It is shown that the treatment of soybean seeds with a fungicide does not significantly change the dynamics of ethylene production by soybean plants in symbiosis with different strains of Bradyrhizobium japonicum under drought conditions. This proves the possibility of using seed inoculation with active rhizobia strains in combination with fungicide treatment for soybean cultivation in arid conditions.

Improved seeds are increasingly being sown in agricultural practice. Such treatments play different roles depending on the substances used. They most often protect seeds and sprouts from abiotic and biotic stresses, but not only. Coating technology is one of the methods of seed improvement, requiring the selection of appropriate components. The purpose of the pot experiment was to test the efficacy of two coatings (C and D) and a commercial inoculant (B) applied to soybean seeds (cultivar Mavka). It was shown that the best option was the combined use of coating and inoculation (C + B or D + B). A significantly higher number of germinated seeds, nodulation, green fodder mass, green fodder protein content, and some physiological parameters of plants were obtained compared to control (A). Applying only the tested coatings (C or D) resulted in the lack of nodulation on roots and slight changes in plant physiological parameters. Sowing seeds with inoculant (B) or control seeds (A) accelerated plant emergence but reduced the number of properly formed sprouts compared to coated seeds. The results confirmed that the tested soybean seed coatings were effective, but in combination with inoculation.

In the future, drought are expected to increase, affecting the productivity of crops sensitive to water scarcity. Through N2-fixation process, soybean is capable of achieving its nitrogen demands, however, this process is inhibited under drought stress conditions. Therefore, it is vital to find suitable solutions for the agricultural sustainability of soybean. Under pot experiment, biocompatibility was studied between Bradyrhizobium japonicum and Trichoderma strains (Trichoderma viride, T. harzianum and T. kongii) for their ability to stimulate the growth, nodulation, N content and photosynthetic pigments of soybean plants under different irrigation intervals (every 2 days (I1), every 4 days (I2), and every 6 days (I3)). The experiment was conducted in summer 2020 with a split-plot randomized complete block design and six replicates. Among the Trichoderma strains, T. harzianum was the most tolerant to growth and auxin production in the maximum 25% PEG 6000 (poly ethylene glycol) concentration. Also, co-inoculation treatment (irrigation every 6 days and inoculation with B. japonicum + T. harzianum) recorded an increase rate reached to 69.4% for shoot length, 102.53% for root length, 79.06% for shoot dry weight, 103.44% for root dry weight and 178.57% for N content compared to control treatment. For physiological traits (chlorophyll a, b, carotenoids and total soluble sugar), there was a significant increase was observed when soybean plants inoculated with B. japonicum + T. harzianum treatment followed by B. japonicum + T. kongii treatment, under irrigation every 6 days condition. On the contrary, a decrease was observed in proline content for the same treatments. Thus, an adequate microbial consortium of Bradyrhizobium - Trichoderma, could represent a promising practical method for increasing the productivity of soybean especially when grown under drought conditions.

The effect of nodule bacteria strain Bradyrhizobium japonicum and the integrated use of the strain and retardant of the triazole class - tebuconazole on linear growth, anatomical structure of Glycine plants and their influence on crop productivity were studied in the field experiment. It was found that both the aplication of Bradyrhizobium japonicum M 8 strain solely and the complex use of the preparations (treatment of the plants with retardant at the beginning of reproductive organ formation, against presowing inoculation of soybean seeds) affected experimental plants’ height, histological parameters of the vegetative organs in comparison with those of untreated control. The use of growth regulators caused changes in the leaf surface area, mesostructural organization of the leaves and accumulation of photosynthetic pigments in them. There were also indicated observable changes in the size of the bark and mechanical tissues of the stem. The effect of the restrictive growth regulators was apparant in the following: the strain of nodule bacteria caused an increase in the linear size of the stem and leaf surface of plants against control. The mutual use of tebuconazole- retardant and strain Bradyrhizobium japonicum led to a decrease in apical dominance of plants, leaf thickness due to increased cell size of wall and spongy parenchymas and intensification of chlorophyll accumulation. Treated plants were characterized by changes in the size of their bark and structural tissues of the stem (collenchyma and sclerenchyma), which is a prerequisite for higher resistance to lodging of plants. The mutual effect of Bradyrhizobium japonicum strain and the triazole preparation proved to be most efficacious among the preparations used. Exogenous application of tebuconazole against the strain of nodule- forming bacteria contributes essentially to the strength of the stem, improves donor functions of Glycine hispida Max, which further secures growth and development of generative organs towards improving yield capasity.

Avoiding the toxicity effect of chemical fungicides on rhizobacteria is a sustainable alternative for agroecosystem management. Rhizobacteria, whose bioprotective and plant growth-promoter potential have been reported in the literature, lack studies on their performance in integrated management with pesticides. Thus, this study aimed to evaluate the effects of azoxystrobin + cyproconazole on the growth of Bacillus subtilis, Streptomyces seoulensis, and Bradyrhizobium japonicum. Three independent experiments were set up, i.e., one for each microorganism, and carried out in a completely randomized design in a factorial scheme (3 × 6), with three doses (recommended by the manufacturer, half, and twice) and six periods of evaluations (48, 96, 144, 192, 240, and 288 hours), with three replications. Growth inhibition rings were evaluated. Azoxystrobin + cyproconazole at all tested doses is compatible with B. subtilis. The use of azoxystrobin + cyproconazole affected the growth of B. japonicum and S. seoulensis, which were sensitive to all its doses until 288 hours after inoculation.

Two domain copper-nitrite reductases (NirK) contain two types of copper centers, one electron transfer (ET) center of type 1 (T1) and a catalytic site of type 2 (T2). NirK activity is pH-dependent, which has been suggested to be produced by structural modifications at high pH of some catalytically relevant residues. To characterize the pH-dependent kinetics of NirK and the relevance of T1 covalency in intraprotein ET, we studied the biochemical, electrochemical, and spectroscopic properties complemented with QM/MM calculations of Bradyrhizobium japonicum NirK (BjNirK) and of its electron donor cytochrome c550 (BjCycA). BjNirK presents absorption spectra determined mainly by a S(Cys)3pπ → Cu2+ ligand-to-metal charge-transfer (LMCT) transition. The enzyme shows low activity likely due to the higher flexibility of a protein loop associated with BjNirK/BjCycA interaction. Nitrite is reduced at high pH in a T1-decoupled way without T1 → T2 ET in which proton delivery for nitrite reduction at T2 is maintained. Our results are analyzed in comparison with previous results found by us in Sinorhizobium meliloti NirK, whose main UV-vis absorption features are determined by S(Cys)3pσ/π → Cu2+ LMCT transitions. Fil: Cristaldi, Julio César. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ferroni, Felix Martín. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Duré, Andrea Belén. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Ramirez, Cintia Soledad. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina Fil: Dalosto, Sergio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina Fil: Rizzi, Alberto Claudio. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina Fil: González, Pablo Javier. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Rivas, Maria Gabriela. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Brondino, Carlos Dante. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Background Soybean [Glycine max (L) Merr.] is an annual leguminous crop serving as a source of food and feed, green manure, biodiesel and fiber. It is nodulated by diverse slow growing and fast growing rhizobia belonging to the genus Bradyrhizobium and Sinorhizobium, respectively. In Ethiopia, it has been cultivated since 1950s with lower grain yield history. Yield improvement efforts have been more concentrated on agronomic studies, inoculation of exotic Bradyrhizobium japonicum including TAL379 and/or fertilizer application. The results have usually been unsatisfactory and inconsistent. This study was initiated to identify promising indigenous soybean rhizobial inoculant that can enhance yield of the crop in the country. Methods Native soybean rhizobia, designated GMR for Glycine max rhizobia, were trapped using soybean (cv. Ethio-Yugoslavia) from soils collected across agro-ecologies of Ethiopia. They were screened for in vitro tolerance against physico-chemical stresses, plant growth promoting (PGP) traits and symbiotic performances at greenhouse and field levels. A reference B. japonicum (TAL379) was included in all experiments. A soybean plant growth promoting Achromobacter sp. was also included in field trials for co-inoculation. Quantitative data were assessed by analysis of variance (ANOVA) employing SAS computer software package version 9.3. Mean separations were undertaken using Duncan’s Multiple Range Test at p ≤ 0.05. Phenotypic variability of the test bacteria was undertaken using PAST4.03 Computer Software. Result GMR that produced acid and grew faster with larger colonies were identified as Sinorhizobium spp. and those which produced alkali and grew slowly with smaller colonies were identified as Bradyrhizobium spp. though further genetic analysis should be performed for verification and identification of their genus and species, respectively. Two Sinorhizobium spp. (GMR120C and GMR125B) profoundly nodulated different soybean cultivars under greenhouse conditions and significantly improved grain yield (p ≤ 0.05; maximum 3.98 tons ha−1) compared to 2.41, 2.82 and 2.69 recorded as maximum grain yield (tons ha−1) for TAL379 inoculation, positive control and negative control, respectively in field trials. Higher yield was recorded when GMR125B was co-inoculated with Achromobacter sp., but when GMR120C was inoculated singly. These GMR also showed efficient utilization of numerous substrates, some PGP traits and potential adaptation to various ecological stresses. Conclusion The two Sinorhizobium spp. (GMR120C and GMR125B) are promising soybean inoculants that can be used to enhance the productivity of the crop in the country.

6S RNA, a conserved and abundant small non-coding RNA found in most bacteria, regulates gene expression by inhibiting RNA polymerase (RNAP) holoenzyme. 6S RNAs from α-proteobacteria have been studied poorly so far. Here, we present a first in-depth analysis of 6S RNAs from two α-proteobacteria species, Bradyrhizobium japonicum and Sinorhizobium meliloti. Although both belong to the order Rhizobiales and are typical nitrogen-fixing symbionts of legumes, their 6S RNA expression profiles were found to differ: B. japonicum 6S RNA accumulated in the stationary phase, thus being reminiscent of Escherichia coli 6S RNA, whereas S. meliloti 6S RNA level peaked at the transition to the stationary phase, similarly to Rhodobacter sphaeroides 6S RNA. We demonstrated in vitro that both RNAs have hallmarks of 6S RNAs: they bind to the σ70-type RNAP holoenzyme and serve as templates for de novo transcription of so-called product RNAs (pRNAs) ranging in length from ∼13 to 24 nucleotides, with further evidence of the synthesis of even longer pRNAs. Likewise, stably bound pRNAs were found to rearrange the 6S RNA structure to induce its dissociation from RNAP. Compared with B. japonicum 6S RNA, considerable conformational heterogeneity was observed for S. meliloti 6S RNA and its complexes with pRNAs, even though the two 6S RNAs share ∼75% sequence identity. Overall, our findings suggest that the two rhizobial 6S RNAs have diverged with respect to their regulatory impact on gene expression throughout the bacterial life cycle.

Introduction: The purpose of this study was to determine the dosage of inorganic fertilizers, soaking time of the inoculation of the legume bacteria strains which were suitable for the growth and yield of peanut in tidal lowland. Materials and Methods: This research was conducted at tidal lowland in Sei Ular Village, Secanggang sub-District, Langkat District, North Sumatra from September to December 2019. The research used randomized block design in factorial. The first factor is the dose of inorganic fertilizers consisting of P0 = un-fertilizer (control), P1= urea 50 kg.ha-1 + TSP 180 kg.ha-1 + KCl 50 kg.ha-1, P2= urea 75 kg.ha-1 + TSP 205 kg.ha-1 + KCl 75 kg.ha-1, P3= urea 100 kg.ha-1 + TSP 230 kg.ha-1 + KCl 100 kg.ha-1. The second factor was the soaking time of the Bradyrhizobium japonicum bacterial strain consisting of T0= un-soaking time, T1= soaking time for 3 minutes, T2= soaking time for 6 minutes, and T3= soaking time for 9 minutes. Parameters were analyzed using ANOVA and BNJ analysis 5%.· Results: The application of urea 50 kg.ha-1 + TSP 180 kg.ha-1 + KCl 50 kg.ha-1 significantly increased the plant height, number of leaves, and root volume and showed the highest number of active nodules, dry pods.plot-1 and seed weight.plot-1 compared to other doses. The seed soaking time with the Bradyrhizobium japonicum strain and their interactions showed insignificant differences in all parameters of peanut plants in tidal lowland.

Bradyrhizobium is a genus of plant growth-promoting rhizobacteria (PGPR) that have been studied for several decades mainly for the ability to fix diazotrophic nitrogen after having been established endosymbiotically inside root nodules of the legumes of Fabaceae. The aim of this work was to evaluate the capability of Bradyrhizobium to promote the growth of crops belonging to other families, in this case, rice (Oryza sativa), both in laboratory and in field trials. For laboratory test, surface-sterilized rice seeds were soaked with cultures of each strain and planted in pots. Plant length and dry weight were measured after 35 days. For the field test, rice seeds of varieties Yerua La Plata and Guri INTA were inoculated with the three best strains observed in the laboratory test and planted in plots. After 60 days of growth, plant length and dry weight were measured. At harvest time, we measured the dry weight of the aerial part, yield and thousand-grain weight. Inoculation with any of the three species described provoked significant increments compared to the uninoculated control at least in one of the parameters measured, both in the laboratory and in the field tests. Bradyrhizobium japonicum E109 was the strain that promoted rice growth the most in the lab while Bradyrhizobium elkanii SEMIA 587 was the strain that promoted rice growth the most in the field, with increments in yield of approximately 1000 kg/ha. Data obtained suggest that the Bradyrhizobium species promoted all rice growth and yield., Centro de Investigaciones en Fitopatología

A suplementação com nitrogênio (N) mineral com diferentes fontes pode incrementar a produtividade e o teor de proteínas dos grãos de soja. Objetivando-se determinar a resposta da soja a fontes e doses de N, associada à inoculação de Bradyrhizobium japonicum, dois experimentos foram conduzidos em Latossolo Vermelho no Cerrado brasileiro, durante a safra 2018/2019. O delineamento experimental utilizado foi o de blocos casualizados, disposto em esquema fatorial 2 × 2 × 5, com quatro repetições. Os tratamentos foram constituídos por dois ambientes (UFMS 1 e UFMS 2), duas fontes de nitrogênio (ureia: 45% de N e sulfato de amônio: 21% de N) e cinco doses de nitrogênio (0, 50, 100, 150 e 200 kg ha–1 de N) aplicados no pleno florescimento (estádio R2). Na formação do legume (estádio R3) foram avaliadas a altura das plantas, teor de clorofila, área foliar e matéria seca aérea. Na colheita foram determinados a inserção do primeiro legume, número de legume, número de grãos por legume, massa de mil grãos, produtividade e o teor de proteínas dos grãos. A adubação não incrementou os componentes de produção, produtividade e o teor de proteína dos grãos, independentemente das fontes e doses de N na aplicação. Por isso, conclui-se que as estirpes de B. japonicum são eficientes para a nutrição de soja cultivada em solo de média a alta fertilidade, não havendo necessidade de se aplicar nitrogênio durante o pleno florescimento.

Accumulation of heavy metals in soil is of concern to the agricultural production sector, because of the potential threat to food quality and quantity. Inoculation with plant growth-promoting bacteria (PGPR) has previously been shown to alleviate heavy metal stress but the mechanisms are unclear. Potential mechanisms by which inoculation with Bradyrhizobium japonicum CB1809 affected the legume soybean (Glycine max cv. Zeus) and the non-legume sunflower (Helianthus annus cv. Hyoleic 41) were investigated in solution culture under 5 μM As stress. Adding As resulted in As tissue concentrations of up to 5 mg kg−1 (shoots) and 250 mg kg−1 (roots) in both species but did not reduce shoot or root biomass. Inoculation increased root biomass but only in the legume (soybean) and only with As. Inoculation resulted in large (up to 100%) increases in siderophore concentration but relatively small changes (±10–15%) in auxin concentration in the rhizosphere. However, the increase in siderophore concentration in the rhizosphere did not result in the expected increases in tissue N or Fe, especially in soybean, suggesting that their function was different. In conclusion, siderophores and auxins may be some of the mechanisms by which both soybean and sunflower maintained plant growth in As-contaminated media.

The present study was conducted to explore the potential of Bradyrhizobium japonicum EI09 (EI09) and selenium (Se) alone or in combination to mitigate hexavalent chromium (Cr6+) stress in Capsicum ...

This study aimed to determine the molecular identities and genetic relatedness of rhizobia isolated from pigeon pea and pinto beans, and assess their remediation potential in the presence of 1 %, 3 % and 5 % (w/v) crude oil in minimal medium for 7 days incubation period. Standard microbiological and molecular methods which include amplification and purification of 16S rRNA, agarose gel electrophoresis, and sequencing. Results showed molecular identities of six rhizobia from pigeon peas as Bradyrhizobium diazoefficiens USDA122, Rhizobium leguminosarum WSM2304, Bradyrhizobium japonicum N61, Rhizobium leguminosarum N741, Rhizobium leguminosarum BIHIB1217, and Bradyrhizobium japonicum E109; and three rhizobia obtained from pinto beans were Rhizobium leguminosarum N871, Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium japonicum SEMIA5079. All tested rhizobia (9) showed petroleum degradation ability, as they all grew in the 1, 3 and 5 % (w/v) crude oil minimal medium under laboratory conditions. B. diazoefficiens USDA122 showed the highest optical density (OD) value of 1.184 ± 0.05 on 7th day at 1 % (w/v) crude oil contamination, while R. leguminosarum N741 has the lowest OD value of 0.372 ± 0.02 at 5 % (w/v) crude oil on 7th day. For all the rhizobia, increase occurred throughout incubation period at 1, 3 and 5 % (w/v) except Rhizobium leguminosarum N741 and R. leguminosarum BIHIB1217. In conclusion, the association of R. leguminosarum BIHIB1217 and R. leguminosarum N871 from pigeon pea and pinto beans respectively, were found most effective in crude oil degradation and thus they are recommended as a promising association for remediation of crude oil spilled soils.

The establishment of the nitrogen-fixing symbiosis between soybean and Bradyrhizobium japonicum is a complex process. To document the changes in plant metabolism as a result of symbiosis, we utilized laser ablation electrospray ionization-mass spectrometry (LAESI-MS) for in situ metabolic profiling of wild-type nodules, nodules infected with a B. japonicum nifH mutant unable to fix nitrogen, nodules doubly infected by both strains, and nodules formed on plants mutated in the stearoyl-acyl carrier protein desaturase (sacpd-c) gene, which were previously shown to have an altered nodule ultrastructure. The results showed that the relative abundance of fatty acids, purines, and lipids was significantly changed in response to the symbiosis. The nifH mutant nodules had elevated levels of jasmonic acid, correlating with signs of nitrogen deprivation. Nodules resulting from the mixed inoculant displayed similar, overlapping metabolic distributions within the sectors of effective (fix+ ) and ineffective (nifH mutant, fix- ) endosymbionts. These data are inconsistent with the notion that plant sanctioning is cell autonomous. Nodules lacking sacpd-c displayed an elevation of soyasaponins and organic acids in the central necrotic regions. The present study demonstrates the utility of LAESI-MS for high-throughput screening of plant phenotypes. Overall, nodules disrupted in the symbiosis were elevated in metabolites related to plant defense.

In Brazil, inoculation with Bradyrhizobium japonicum strains is the main form of N assimilation by soybeans, but there are reports of the use of mineral N as a complement to the demand of this nutrient by the plant. The objective of this work was to verify the effect of different forms and times of N application on vegetative growth and soybean crop yield in northern Mato Grosso. The experimental design was a randomized block design (DBC) with 10 treatments: control (no N application); and in all other treatments 10 kg ha-1 of N was applied, changing season and form of application as: the haul in cover at planting; in V2 at hedging; in V2 via leaf; in V4 at hedging; of N in leaf V4; from N in R1 to hedging; N in leaf R1; in R2 at cover and in R2 leaf. The cultivar used was Bonus from Brasmax®. Vegetative growth was evaluated by height, stem diameter, shoot dry mass, nodulation by number of nodules and yield by variables, number of pods, grains per pod, mass of 1000 grains, and weight. productivity. In practically all variables analyzed, no effects of nitrogen application on soybean crop were verified. The shoot dry mass was higher when nitrogen was applied to V2 via foliar spraying and to V4 in soil cover. In general, although there was no statistical difference between treatments, N application at the beginning of crop development increased soybean yield. The application treatment V2 was the most productive, produced 34% more than the control without N, or 17.34 more bags than the control.

The objective of this study was to evaluate the residual effects of nitrogen (N) fertilization liberation of mulching soybean crop in the yield corn of-season. The sowed was the corn hybrid Land® in date 01/26/2017, of mulching soybean crop experiment, in Sinop-MT, Brazil. The experimental design was a randomized complete block with four replications with teen treatments. The treatments were: control without N application (only inoculated with Bradyrhizobium japonicum e B. elkanii) and the other treatments was applied the dose of 10 kg ha-1 of N in different phenological stages and modes of application (the cover in the sowing; in V2 the haul in coverage; in V2 via leaf; in V4 the haul in coverage; in V4 via leaf; at R1 the coverage haul; in R1 via leaf; in R2 the cover and R2 in the leaf). The traits components of the yield analyzed were: number of rows of grain, number of grains per rows, the thousand-grain weight and yield grains. The mineralization of the nitrogen provenient of mulch the soybean crop is not sufficiency for corn off-season crop. The application of nitrogen in the stages V2 and R1 in coverage in the soybean predecessor crop provided the highest values to yield grains of the maize off-season crop.

Beneficial soil bacteria including Pseudomonas fluorescens, Burkholderia, cepacia, Azotobacter vinelandii, Rhizobium leguminosarum and Bradyrhizobium japonicum identified by 16S rRNA gene sequence analysis tolerated maximum concentrations of glyphosate (herbicide) and kitazin (fungicide). Pesticides declined the phytohormone-synthesizing ability of PGPR strains. As an example, the higher (3X) level of kitazin reduced maximally IAA synthesizing ability of PGPR strains PS3, PSBB1, AZ2, RP1 and RV9 by 51, 28, 82, 35 and 59%, respectively, than control. Impact of different concentrations of glyphosate and kitazin on bacterial proteins differed considerably (p

Soybean [Glycine max (L.) Merrill] is cultivated intensively in India. Rhizobium sp. associated with it derives nitrogen (N) by biological nitrogen fixation under field conditions. Out of total 25 isolated sp. from functional root nodules of soybean plants on congo-red yeast extract mannitol agar medium, 20 slow grower Bradyrhizobium sp. and 5 fast grower Rhizobium sp. were found on growing YEMA media supplemented with bromothymol blue. The purified strains were aerobic, gram negative, non-spore forming and motile rods. The optimum growth kinetics for both sp. was 35 °C at neutral pH (7.0). Both fast and slow growing rhizobia were found to be positive for oxidase, KOH, starch hydrolysis, nitrate reduction and catalase activity. Among all the 25 isolates tested, 23 isolates showed positive reaction to gelatin hydrolysis except Bj-11 and Bj-21 while, 21 isolates were reacted positive to H2S production whereas, the four isolates viz., Bj-1, Bj-2, Bj-8 and Bj-23 were negative in reaction. While all the samples were found negative for IAA production. Pot culture experiment revealed that seed inoculation with these isolates recorded significant improvement in nodule number and plant height ranged from 3.00 to 22.00 nodules per plant and 35.00 to 65.00 cm respectively at flowering stage over uninoculated control. Isolates viz., Bj-9, Bj-10, Bj-14, Bj-17, Bj-19, Bj-23, Bj-25 could produce large and pink nodules indicating their effective symbiosis with soybean.

The effect of pre-sowing treatment of soybean seeds with fungicides on the intensity of ethylene release, the processes of nodulation and nitrogen fixation in different symbiotic systems in the early stages of ontogenesis were investigated. The objects of the study were selected symbiotic systems formed with the participation of soybean (Glycine max (L.) Merr.) Diamond variety, strains Bradyrhizobium japonicum 634b (active, virulent) and 604k (inactive, highly virulent) and fungicides Maxim XL 035 PS (fludioxonil, 25 g/L, metalaxyl, 10 g/L), and Standak Top (fipronil, 250 g/L, thiophanate methyl, 225 g/L, piraclostrobin, 25 g/L). Before sowing, the seeds of soybean were treated with solutions of fungicides, calculated on the basis of one rate of expenditure of the active substance of each preparation indicated by the producer per ton of seed. One part of the seeds treated with fungicides was inoculated with rhizobium culture for 1 h (the titre of bacteria was 107 cells/mL). To conduct the research we used microbiological, physiological, biochemical methods, gas chromatography and spectrophotometry. It is found that, regardless of the effectiveness of soybean rhizobial symbiosis, the highest level of ethylene release by plants was observed in the stages of primordial leaf and first true leaf. This is due to the initial processes of nodulation – the laying of nodule primordia and the active formation of nodules on the roots of soybeans. The results show that with the participation of fungicides in different symbiotic systems, there are characteristic changes in phytohormone synthesis in the primordial leaf stage, when the nodule primordia are planted on the root system of plants. In particular, in the ineffective symbiotic system, the intensity of phytohormone release decreases, while in the effective symbiotic system it increases. At the same time, a decrease in the number of nodules on soybean roots inoculated with an inactive highly virulent rhizobia 604k strain due to the action of fungicides and an increase in their number in variants with co-treatment of fungicides and active virulent strain 634b into the stage of the second true leaf were revealed. It was shown that despite a decrease in the mass of root nodules, there is an increase in their nitrogen-fixing activity in an effective symbiotic system with the participation of fungicides in the stage of the second true leaf. The highest intensity of ethylene release in both symbiotic systems was recorded in the stage of the first true leaf, which decreased in the stage of the second true leaf and was independent of the nature of the action of the active substances of fungicides. The obtained data prove that the action of fungicides changes the synthesis of ethylene by soybean plants, as well as the processes of nodulation and nitrogen fixation, which depend on the efficiency of the formed soybean-rhizobial systems and their ability to realize their symbiotic potential under appropriate growing conditions.