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The nitrogen (N) requirement for barley cultivation can vary from 90 to 130 kg ha−1 cycle−1, representing 30% of production costs. Furthermore, obtaining mineral N is difficult due to constant conflicts involving producing countries. Excess N will increase the cost of production and contaminate the soil and groundwater, unbalancing the fauna, flora, and microbiology of the environment. The objective of this research was to evaluate the management of inoculation and N fertilization with A. brasilense on the development and productivity of barley. Field experiment was carried out for two years. A randomized block design was used in a 5 (Factor A) × 2 (Factor D) factorial arrangement with four replications. In which the "factor A" included five doses of A. brasilense, whereas the "factor D" was evaluated N management (with or without N management). The inoculant used had approximately of 2.0 × 108 viable cells mL−1 (Ab-V5 and Ab-V6 strains). Innoculation was carried out on the seeds 1 hour before sowing, in order to homogenize the inoculant in the seeds, to guarantee homogeneity of the distribution of microorganisms on the seeds. The best dose of A. brasilense was 12.5 mL kg−1 of seed, which provided an increase in plant height, number of ears, mass and grain productivity. The use of A. brasilense showed significant improvements in management with or without the use of mineral N. However, better results are obtained when the association between N management and the use of inoculant is made. Thus, when using up to 22.5 kg of N, the best results were observed. [ABSTRACT FROM AUTHOR]

The yield gain of soybean inoculated with Bradyrhizobium spp. or co-inoculated with Bradyrhizobium spp. and Azospirillum brasilense is variable. Inoculants can be applied in the sowing furrow or via seed treatment. There is a gap in our understanding of the efficacy of different inoculation methods. This study aimed to assess the agronomic efficiency of soybean inoculated and co-inoculated with Bradyrhizobium spp. and A. brasilense by different methods. The study was conducted in Paraná State, Brazil, in two seasons. Five treatments were tested: control; seed treatment with Bradyrhizobium spp. (SBr), seed treatment with Bradyrhizobium spp. + A. brasilense (SBr+Az), in-furrow treatment with Bradyrhizobium spp. (FBr), and in-furrow treatment with Bradyrhizobium spp. + A. brasilense (FBr+Az). Shoot dry weight, grain nitrogen content and grain yield were lower in 2018/19. In 2017/18, FBr+Az increased nodule number and dry weight compared with SBr. FBr+Az promoted a 47% increase in pods per plant compared with the control in both seasons. Regardless of season, grain nitrogen content was higher with FBr+Az (mean relative increase of 27%). FBr+Az was superior to SBr+Az in 2017/18, with a 12% increase in yield. Inoculation and co-inoculation improve morphological traits and soybean yield. In-furrow inoculation is more efficient than seed treatment. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate sorghum hybrids associated or not associated with Azospirillum brasilense and nitrogen fertilization (N) during planting on the yield, fermentative profile, and nutritional value of the respective silages. Five sorghum hybrids (Volumax, 201813B, 201814B, 201709B, BRS716) were evaluated with three nitrogen fertilization strategies using urea (100 kg ha-1 of N) and Azospirillum brasilense, and urea (100 kg ha-1 of N)/A. brasilense in association. A randomized block design was used in a 5 x 3 factorial scheme, with five hybrids, three fertilization strategies and three replications (blocks). The useful area of each experimental unit was 3 m x 3 m. The biomass sorghum hybrids showed a dry matter (DM) production (P = 0.01) 48.31% higher than the DM production of the Volumax forage (mean of 17.49 t ha-1 of dry matter). There was no difference between the sorghum hybrid silages in the pH values (mean of 4.11; P = 0.68), gas losses (mean of 3.74% of DM; P = 0.19). The sorghum hybrids biomass 201709B and BRS 716 showed better digestible and DM productivity. Azospirillum brasilense can be used as a nitrogen fertilization strategy in partial or total replacement of urea. [ABSTRACT FROM AUTHOR]

Soilless crops have become an important alternative for large-scale vegetable production because of the quality of their products and optimization of resources. Brassinosteroids (Brs) and Plant Growth-Promoting Bacteria (PGPB), has been reported to promote growth and physiological parameters in soil crops, but there are few reports on the application of these compounds in soilless crops. The effects of Brs ((25R)-3β 5α-dihydroxy-spirostan-6-one) and three strains of PGPB (Bacillus velezensis, Pseudomona sp., and Azospirillum brasilense) on the growth and yield of lettuce under hydroponic conditions were evaluated. Two separate experiments were carried out: one using a substrate in pots under greenhouse conditions and the other using a deep-flow hydroponic system in a growth room with artificial LED lighting. Plant physiological parameters (yield, dry weight, root surface area, and leaf area) and PGPB attributes under in vitro tests (phosphate solubilization and indole-3-acetic acid (IAA) synthesis) were determined using in vitro tests. A completely randomized design was used in all experiments. The results showed that in in vitro tests Azospirillum brasilense and Pseudomonas sp. were the strains that synthesized the highest amounts of IAA (36 mg mL−1 and 34 mg mL−1, respectively). Phosphorus solubilization was significantly higher in the Pseudomonas sp. strain (110.35 µg mL−1). Regarding physiological and quality parameters, the application of Brs (0.5 ppm), Bacillus velezensis, and Azospirillum brasilense (1 × 106 CFU mL−1) caused an increase between 20% and 40% on variables such as plant yield, leaf area, root surface area, and colorimetry of lettuce for substrate or hydroponic conditions, respectively. [ABSTRACT FROM AUTHOR]

This study was developed to investigate the interactive effect of silicon (Si) application and the inoculation of plant growth promoting bacteria (PGPB) Azospirillum brasilense on wheat nutrient uptake and accumulation on biomass and grains when combined with nitrogen (N) application rates. The study was set up in a Rhodic Hapludox under no-till system, located in Selvíria, state of Mato Grosso do Sul, Brazil (tropical Savannah region). Treatments were tested in a randomized complete block design with four replicates, arranged in a full factorial design 2 × 2 × 5 and included: i) two soil amendment sources (Ca and Mg silicate as Si source and dolomitic limestone); ii) two seed inoculation (with and without A. brasilense) and iii) five N application rates applied as side-dress (0, 50, 100, 150 and 200 kg ha−1). Increasing N application rates positively influenced wheat nutrition with increased nutrient and Si uptake in shoot. Calcium and Mg silicate positively influenced wheat nutrition with greater shoot Si and grain N, P, K, B, Cu, Fe, Mn, Zn and Si uptake. In addition, Si was the third and sixth element most absorbed in wheat shoot and grain respectively. Inoculation with A. brasilense was found to increase nutrient uptake with greater shoot K and S and grain N, P, K, Mg, S, B, Cu, Mn, Zn and Si uptake. Azospirillum brasilense inoculation provided greater N uptake, with an increase of 5.8 and 8.9% on shoot and grain uptake. [ABSTRACT FROM AUTHOR]

We investigated how plant inoculation with two diazotrophic bacteria would influence the modulation of root architecture and parameters associated with N uptake rate under high and low NO3− availability. The treatments were arranged in a 2 × 3 factorial design, the first factor being N dose (0.3 and 3.0 mM, or low and high N, respectively) and the second being inoculation with Herbaspirillum seropedicae strain ZAE94 (Hs-ZAE94), Azospirillum brasilense strain Sp245 (Ab-Sp245) and an uninoculated control. The parameters evaluated were: root architecture, mineral N in the growth solution, soluble metabolites, and activities of two N enzymes, dry mass, N accumulation, and the ratio of plant dry mass to N accumulation (NUE). Plant parameters improved with higher N availability. Only under high N, the inoculation with Ab-Sp245 brought about a change in root architecture with an improvement in root surface area, which was in agreement with an increased plant dry matter, N accumulation, and NUE, which was not always observed on either sampling date, 24 and 32 days after transfer to the hydroponic system. The shift in root architecture and the maintenance of N uptake per unit of root area by inoculation with Ab-Sp245 was likely the main effect. [ABSTRACT FROM AUTHOR]

The increase in the world population creates the need for sustainable food production and the use of synthetic fertilizers with growth-promoting bacteria. The objective of this research was to evaluate the acidity on the physiological and productive variables of wheat inoculated with Azospirillum brasilense and treated with osmoprotective additives. Combinations of A. brasilense, osmoprotectant and chemical treatment were evaluated in wheat seeds planted in contrasting acidity soil (pHs: 4.8 and 6.5). Evaluations of the physiological parameters were carried out in the foliar tissue (hydrogen peroxide content, superoxide dismutase activity, lipid peroxidation, content of chlorophyll a, b, and total and carotenoid and nitrate reductase enzyme activity) during the vegetative period and flowering. The grain yield components were evaluated after the physiological maturation. Plants grown in uncorrected soil acidity (pH: 4.8) showed higher lipid peroxidation. The other plants (pH: 6.5) have higher levels of nitrate reductase. Higher nitrate reductase activity was also observed in plants inoculated with A. brasilense. Therefore, in soil acidity 6.5, both A. brasilense isolate or combined with osmoprotective additive increased the grain yield. Nevertheless, the osmoprotectant application did not attenuate the effects of the chemical treatment of seeds and exerted a negative effect to inoculation with A. brasilense. [ABSTRACT FROM AUTHOR]

Rainfall variations can occur with crops in field condition which can result in soil water restrictions and impair crop development. Inoculation with Azospirillum genus bacteria can be presented as an alternative, as it has the ability to fix N2, promote root growth and produce beneficial metabolites to plants under water stress conditions. Thus, the objective was to co-inoculate A. brasilense and Bradyrhizobium sp. in cowpea and verify the potential to minimizing the effects caused due to water availability on root growth and nodulation. The study was carried out in a greenhouse with completely randomized block design and 4 replications in 4 × 4 factorial arrangement, the treatments being: (i) non-inoculated, (ii) N-fertilizer, (iii) inoculated with Bradyrhizobium sp. and (iv) co-inoculated with Bradyrhizobium sp. + A. brasilense. All treatments were associated with soil water tension of 15, 30, 45 and 60 kPa. Co-inoculation increased dry mass and nodules number. The root surface area and dry mass of cowpea roots showed an increase from the 50.55 kPa tension with co-inoculation. [ABSTRACT FROM AUTHOR]

The interactive effect of Azospirillum brasilense inoculation and nitrogen (N) rates on Ora-pro-nobis (Pereskia aculeata Mill.) is poorly understood. Ora-pro-nobis (OPN) could be an important horticultural plant to promote a diverse and healthy diet to combat macronutrients and micronutrients deficiencies, particularly in developing countries. The objectives of this research were to assess the effect of inoculation with A. brasilense combined with N rates on OPN development, yield and leaf nutrients content under greenhouse conditions. Treatments were tested in a randomized completely block design with four replicates, arranged in a full factorial design 2 × 5 and included: i) two inoculations (with and without A. brasilense) and iii) five N application rates (0, 50, 100, 150 and 200 kg ha−1 applied in two split application as ammonium sulfate source). Inoculation with A. brasilense benefited OPN growth and development, leading to a greater leaf biomass, even combined or not with N application rates. In addition, A. brasilense inoculation increased OPN nutrition with increased leaf N, P, K, Ca, Mg, S, Fe and Zn concentrations. Azospirillum brasilense combined with 150 kg N ha−1 increased leaf biomass by 40% in sampling 1, and in sampling 2, A. brasilense inoculation increased leaf biomass by 8.8% regardless N application rates. Therefore, A. brasilense inoculation could be an important practice to increase OPN cultivation, development, nutrition and yield. Ora-pro-nobis showed high nutrient content in leaf tissue, therefore, OPN plant can be an interesting source of nutrients to human consumption. Nitrogen application rates benefited OPN growth and development leading to a greater leaf biomass. In addition, N application rates increased OPN nutrition with increased leaf N, P, Ca, Mg, S, Cu, Mn and Zn concentrations. However, increasing N rates decreased leaf K concentration. Therefore, long-term studies are required to better understand the role of A. brasilense under different N management and their effects on OPN development and nutritional properties, aiming to reduce N application rates and improve N management in OPN cultivation. [ABSTRACT FROM AUTHOR]

This study was developed to investigate if Ca and Mg silicate application as Si source combined with inoculation with Azospirillum brasilense and N rates can affect corn nutrient uptake. The study was set up in a Rhodic Hapludox under no-till system, located in Selvíria, state of Mato Grosso do Sul, Brazil. Treatments included: (i) two seed inoculation (with and without A. brasilense); (ii) two soil amendment sources (Ca and Mg silicate as Si source and dolomitic limestone); and (iii) five N application rates applied as side-dress (0 to 200 kg ha−1). Increasing N rates positively influenced corn nutrition with increased nutrient and Si uptake in shoot and grain. The average nutrient uptake in descending order was K > N > Ca > Si > Mg > S > P >Fe > Mn > Zn > Cu > B for shoot and N > K > P > S > Mg > Ca > Si> Fe > Zn > Mn > B > Cu for grain. Calcium and Mg silicate application positively influenced corn nutrition with greater shoot P, K, Ca, S, and B uptake and grain Ca uptake. Inoculation with A. brasilense was found to increase nutrient uptake with greater shoot N, K, Ca, B, and Si and grain Cu uptake. Grain N and S increased by 22.5 and 26.8% when plants were inoculated and 200 kg N ha−1 was applied and grain Zn increased by 88.6, 65.7, and 99% when plants were inoculated and 50, 150, and 200 kg N ha−1 were applied, respectively. Therefore, studies conducted under tropical conditions are needed to better understand the role of Si combined with PGPB inoculation under different N management and their effects on plant nutrition and cereal development aiming at improving nutrient replenishment. [ABSTRACT FROM AUTHOR]

Field experiments were conducted for two successive seasons July 2018 to November 2018 and July 2019 to November 2019 at the Fruit Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry, Jhalawar district under Rajasthan state of India. The experiment consisted of different treatments of Azospirillum brasilense (AZS) and Vermicompost (V.C.). It was laid out in a Randomized Block Design with three replications. The 16 different treatment combinations of AZS and Vermicompost were applied to soil canopy of custard apple cv. Balanagar plants during first week of July 2018 and July 2019 in canopy rhizosphere of black vertisols in custard apple plants. Among different treatment combinations, T10 treatment consisting of AZS @ 50 g + V.C. @10 kg/plant was found relatively better over all other treatments with respect to most of the plant growth characteristics, including soil health properties and microbial population density in soil availability in canopy of custard apple cv. Balanagar plants. The pooled results of two years revealed comparative better plant growth parameters viz. rootstock girth (74.20 mm), scion girth (61.52 mm), plant height attribute (3.46 m), number of nodes per shoot (13.00), number of nodes per branch (86.17), number of shoots per branch (26.00), number of shoots per plant (151.00) have shown augmenting response in improvement of plant growth parameters under T10 treatment (AZS @ 50 g + V.C. @ 10 kg /plant) in custard apple cv. Balanagar plants. However, key soil parameters concerning bulk density (1.32 g/cm3), soil pH (7.39), and electrical conductivity (0.46 dS m−1) reduced significantly under T10 treatment over other treatments. The soil physico-chemical properties especially change in porosity (55.04%), organic carbon (0.55%), available nitrogen content (350.55 kg/ha), available phosphorous content (46.51 kg ha−1) and available potassium content (322.34 kg ha−1), bacterial population (26.67 cfu g−1), fungi population (15.00 cfu g−1) and actinomycetes population (10.00 cfu g−1) have shown tremendous response in improvement of soil parameters under T10 treatment (AZS @ 50 g + V.C. @ 10 kg /plant) with respect to overall soil health. [ABSTRACT FROM AUTHOR]

The massive use of inputs is often applied in common bean for nitrogen (N) supply, better plant development, and to prevent plant disease. Instead, the co-inoculation of Rhizobium, Azospirillum and Trichoderma may play the same role; however, its effects are unknown in common bean. This work aimed to evaluate the effects of co-inoculating three microorganisms on the development, nodulation and grain yield (GY) of a common bean. The experiments were carried out on a randomized block design with four replicates. The treatments were NI: not inoculated; Rt: inoculated with Rhizobium tropici; Rt+Ab: inoculated with Rt and Azospirillum brasilense; Rt+Ab+Ta: inoculated with Rt, Ab and Trichoderma asperellum; Nf120: 120 kg ha−1 of N. In the inoculated treatments, the seeds were treated with Rt inoculant and with Ta inoculant before sowing, using a dose of 10 g of each inoculant kg−1 of seed. The inoculant containing the Ab was sprayed out in a dose of 300 mL ha−1 at the V2/V3 phenological stage. Evaluations were performed for the number of nodules (NN), nodule dry weight (NDW), root dry weight (RDW), shoot dry weight (SDW), pod number (PN), grain number (GN) and GY. NN and NDW were higher in NI and Rt treatments. The Rt+Ab treatment resulted in higher SDW, whereas the same treatment and Rt+Ab+Ta provided higher RDW and SDW, resulting in values similar to those of the Nf120 treatment. Innoculation with rhizobia (Rt) provided PN and GN equivalent to those of the Nf120 treatment. The inoculation (Rt) and co-iconulation (Rt+Ab) resulted on GY of 2946.27 and 2892.42 kg ha−1, respectively, surpassing the Nf120 treatment, which was 2741.91 kg ha−1. These results indicate that Rt inoculation and Rt+Ab co-inoculation can be alternatives to the substitution of nitrogen fertilizers, guaranteeing high GY levels in common bean. [ABSTRACT FROM AUTHOR]

In Egypt, the total area of agricultural land is 3.36 million acres, which is 3.8% of the country entire territory. One of the main obstacles to agricultural production in Egypt is soil salinization and degradation. Therefore, saline-sodic soil reclamation in arid regions is highly relevant. This study aimed to use Azospirillum inoculation with eco-friendly organic wastes for free remediation of saline-sodic soils. In this work, nine treatments included two levels of spent grain (S1 and S2), two levels of compost (C1 and C2), a mix of both sources (C1S1), Azospirillum (A1), a mix of both sources with Azospirillum (A1S1 and A1C1) and untreated control. The treatments were previously incubated with soil at field capacity for five months under laboratory conditions at 28°C. The most relevant chemical and biological parameters were analyzed every month for five months. Results indicate that Azospirillum inoculation with spent grain increased soil organic carbon (TOC), dehydrogenase and urease enzymes, micro-nutrients iron (Fe2+), zinc (Zn2+), manganese (Mn2+), copper (Cu2+), and boron (B+), and macro-nutrients nitrogen (N), phosphorus (P) and potassium (K); while decreased exchangeable sodium percentage (ESP), pH and EC, by 75%, 12%, and 43% respectively, compared to initial conditions. A significant variation was observed in chemical and biological properties among all treatments in the order of S2 ≥ A1S1> A1 > C2 > C1S1 > A1C1 > C1 > control > initial. In conclusion, the addition of Azospirillum with the spent grain is highly recommended for the saline-sodic soil amelioration. It is more effective than compost to remediate and enhance saline-sodic soils fertility. [ABSTRACT FROM AUTHOR]

Field trials in two sowing dates were conducted to assess the possibility of applying bioagents as wheat grain dressing for suppressing severity of foliage diseases, i.e. powdery mildew, septoria leaf blotch and stem rust under field conditions. Bioagents, such as Bacillus subtilis, Azospirillum brasilense, Pseudomonas fluorescens, Trichoderma harzianum and Plant Guard as well as the fungicide Topsin M70, were evaluated. All treatments reduced diseases severity compared with control. Generally, Giza 171 cv. represented the lowest diseases severity followed by Misr 1 and Gemmiza 12. Moreover, early sown cultivars (10th November) showed lower disease severity than those sown late (10th December). Wheat grains treated with B. subtilis and T. harzianum revealed the highest effect on all diseases severity followed by the other applied treatments. Overall, such applied treatments have the possibility to suppress wheat foliar diseases as a safe alternative to chemical fungicides and avoid harmful effect for human health and polluting the environment. [ABSTRACT FROM AUTHOR]

Using sustainable management to maximize crop yield without increasing production costs is one of the great challenges of modern agriculture. This study aimed to evaluate the effect of nitrogen (N) supply management, associating inoculation with Rhizobium tropici, co-inoculation schemes with Azospirillum brasilense and mineral top-dressing fertilization, on the agronomic and qualitative performance of early-cycle common bean cultivars. The experiment was installed in a randomized block design, in a 2 x 12 factorial scheme (2 cultivars and 12 N supply management), with four repetitions. The N supply management consisted of the association of mineral fertilization with N (45 and 90 kg ha−1 of N in top-dressing), inoculation of seeds with Rhizobium tropici and co-inoculation of seeds and leaves with Azospirillum brasilense. The agronomic and qualitative performance of common bean was affected by the nitrogen supply management and by the cultivars, and the response was independent of the interaction between cultivars and N supply management. Except for plant dry mass, all variables analyzed showed maximum response in the treatment of seed inoculation with Rhizobium tropici, leaf-spray of Azospirillum brasilense and mineral top-dressing fertilization with 90 kg ha−1 of N, which led to a 27% increase in yield compared to the control. The cultivar IAC Imperador has a superior agronomic performance (grain yield = 2,840 kg ha−1) compared to IPR Curió (2,484 kg ha−1). The results demonstrated the feasibility of using co-inoculation with Azospirillum brasilense as a tool to increase yield, grain quality and sustainability in common bean production systems. [ABSTRACT FROM AUTHOR]

This work intended to evaluate the contribution of single inoculation of diazotrophic bacteria Herbaspirillum seropedicae or Azospirillum brasilense on growth and yield of maize crop at different levels of N fertilization. Two field experiments were carried out in the summer and winter seasons. Factorial design combined four fertilization levels (0, 50, 100 and 150 kg N ha−1) and three seed inoculations (non-inoculation, strains Hs-ZAE94 or Ab-Sp245), with four replications. Shoot dry matter, leaf area index, and N accumulation were evaluated in weekly samplings, and grain yield measured at maturity. Most expressive responses of inoculation were observed in the summer crop, with minor effects in the winter crop when growth and yield were lower. In the summer, inoculation increased shoot dry matter and leaf area of maize plants, enhancing crop growth rate, and increased N accumulated by shoots, particularly at low levels of N supply. In the summer, Hs-ZAE94 increased grain yield at the levels of 0, 50 and 100 kg N ha−1, and Ab-Sp245 at 100 kg N ha−1, as compared to non-inoculation. Inoculation with Hs-ZAE94 associated with 50 kg N ha−1 provided similar grain yield than the non-inoculation with 150 kg N ha−1, improving N use efficiency. [ABSTRACT FROM AUTHOR]

New studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2 × 5 × 2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200 kg ha−1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140 kg ha−1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization. [ABSTRACT FROM AUTHOR]

Climate change is imposing high temperature resulting in prolonged drought episodes and shrinking of fresh water resources across the globe. In this scenario, even drought tolerant crops like quinoa are also losing significant yield. However, this study was planned to investigate the impact of drought on quinoa at critical growth stages and bacterial inoculation to improve drought tolerance. Drought was imposed by maintaining 25% pot water holding capacity (PWC) at multiple leaf, flowering, and seed filling stage (DSFS), while 80% PWC was considered as control. Three strains of plant growth promoting rhizobacteria (PGPR) named as: Bacillus licheniformis, Pseudomonas fluorescens, and Azospirillum brasilense were inoculated with quinoa seeds before sowing with respect to drought treatments. PGPR inoculation mitigated the drastic effects of drought by improving crop growth, net assimilation rate, water use efficiency, leaf chlorophyll, and phenolic contents, all of these ultimately contributed to improvement in grain yield and its contributing attributes. Moreover, PGPR markedly improves the grain quality attributes including protein, phosphorus, and potassium contents. Principal component analysis linked the different scales of study and demonstrated the potential of physio-biochemical traits to explain the quinoa yield variations under drought condition with response to PGPR inoculation. Among different PGPR, A. brasilense was found most effective both under normal and drought conditions. Overall, DSFS has more detrimental effects among critical growth stages of quinoa and A. brasilense can be used as a shotgun tactic to ameliorate drought stress in quinoa. [ABSTRACT FROM AUTHOR]

Biochar has been used as an amendment for disturbed soils. However, the changes of the rhizobacterial community after the biochar addition in mine soils, has not yet been elucidated. The aim of this study was to evaluate the response in the rhizobacterial communities of Brachiaria decumbens during different reclamation processes of coal mining using biochar. Five treatments were carried out: control, mine soil + biochar, mine soil + biochar + Azospirillum brasilense, mine soil + biochar + arbuscular mycorrhizal fungal + Mortierella sp. DNA from the rhizospheric soil was sequenced by Ion Torrent. The relative abundance in each sample was calculated. The Proteobacteria (70%) and Actinobacteria (23%) phyla dominated the rhizobacterial community composition during the establishment time. Seven months after seeding, Actinobacteria decreased significantly, while Proteobacteria increased. The Acidobacteria phylum was higher in the control. There was a higher abundance of Proteobacteria with the biochar treatments than for the control, thus the baseline for the rhizobacterial community changes induced by biochar was provided. The alpha diversity index showed the effect of biochar on the diversity and dominance of the rhizobacterial communities. The hierarchical clustering tree showed a correlation between the treatments with biochar, and a significant differentiation between these and the control treatment. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of plant growth promoting bacteria (PGPB) inoculation in Zuri guinea grass [Megathyrsus (syn. Panicum) maximus] on shoot dry weight (SDW) and root dry weight (RDW) yield, morphological compositions, number of tillers, and nutrients concentrations in SDW. The experiment was carried out under greenhouse conditions in a randomized block design consisting of eight treatments with five replicates. The inoculation with the Ab-V5 and Ab-V6 strains of Azospirillum brasilense and Pseudomonas fluorescens or co-inoculation with Rhizobium tropici and Ab-V6, with nitrogen (N) fertilization, as well as re-inoculations of the plants after cuttings were taken were evaluated. The plant growth-promoting bacteria and N fertilization promoted increases in SDW and RDW yield, tillers dry weight, relative chlorophyll index (RCI) and nutrients uptake in shoots of Zuri guinea grass. There were effects of re-inoculation the PGPB by P. fluorescens in shoots, N, magnesium (Mg) and boron (B) concentration in SDW. [ABSTRACT FROM AUTHOR]

Alternative options to feed an ever-growing global population requires to be developed to supplement chemical fertilizer use. Nitrogen (N) is the chemical fertilizer most used for non-legume crops. Research showing the potential for management practices which supplement the use of N fertilizer is utmost important. This research was developed to investigate the potential use of Azospirillum brasilense to enhance micronutrient accumulation in wheat cropping systems; and, to assess the potential interactions between biological nitrogen fixation (BNF) and urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT). The objective was to evaluate the effect of N sources and doses associated with inoculation with A. brasilense, regarding micronutrients accumulation, and its influence on wheat grain yield in Savannah conditions. The study was carried out in a Rhodic Hapludox under no-tillage. The experimental design was a randomized complete block design with four replications arranged in a 2 × 5 x 2 factorial scheme: two N sources (urea and urea with NBPT), five N rates (0, 50, 100, 150 and 200 kg ha−1), with and without A. brasilense inoculation. N rates increased the uptake and removal of micronutrients. Urea with NBPT was not efficient in optimizing nitrogen fertilization. Inoculation with A. brasilense provided a higher accumulation of Cu, Fe, Mn and Zn in the straw and Mn and Zn in grains. The inoculation with A. brasilense associated with 140 kg ha−1 of N provided increased wheat grain yield. [ABSTRACT FROM AUTHOR]

The nitrogen fertilisation management should focus on increasing fertilisation efficiency in favour of a more sustainable and productive agriculture. Thus, this study aimed to evaluate the effect of inoculation with Azospirillum brasilense, associated to N doses and sources, in Savannah conditions, on agronomic efficiency (AE), recovery of applied nitrogen (RAN), physiological efficiency (PE), agrophysiological efficiency (AGREC), nitrogen use efficiency (NUE), nitrogen harvest index (NHI) and wheat grain yield. The experiment was developed in a Rhodic Hapludox soil under no-tillage system. The experimental design was a randomised complete block design with four replicates arranged in a 2 × 5×2 factorial scheme: Two N sources [(urea and urea with inhibitor of the enzyme NBPT (N – (n – butyl thiophosphoric) Triamide))], five N doses applied in top-dressing (0, 50, 100, 150 and 200 kg ha−1), with and without inoculation with A. brasilense. The increase in N doses reduced the nitrogen fertilisation efficiency. No significant differences were observed among the N sources. Inoculation increased the AE of nitrogen sources and can increase RAN. The increase in N dose up to 140 kg ha−1 associated with inoculation increased wheat grain yield. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T0 – no-inoculation (control), T1 – Azospirillum brasilense inoculation, T2 – Rhizobium pisi inoculation and T3 – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T3 were about 9% and 14% higher than values for sole inoculations in T1 and T2. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of strains of Azospirillum brasilense, Pseudomonas fluorescens and Rhizobium tropici on the shoot dry weight (SDW) and root dry weight (RDW) yield, N uptake and nutritive value of 'Mavuno' grass inoculated with plant growth-promoting bacteria. We evaluated the effects of inoculation with the Ab-V5 and Ab-V6 strains of Azospirillum brasilense and Pseudomonas fluorescens or co-inoculation with Rhizobium tropici and Ab-V6, with and without nitrogen (N) application, as well as re-inoculations. The growth promoting bacteria + N promoted increases in SDW and RDW yield, tillers dry weight, relative chlorophyll index and N uptake. There were no effects of re-inoculation by Azospirillum brasilense, Pseudomonas fluorescens and Rhizobium tropici on nutrition, nutritive value and SDW and RDW yield, demonstrating that this technique still needs further studies with 'Mavuno' grass in the form and the correct period to be performed. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) containing more than three rings are mainly less biodegradable. Therefore, the isolation of PAHs-degrading bacteria is of great importance to be augmented for bioremediation of polluted sites with PAHs. PAHs-degrading bacteria were isolated from contaminated sites of an oil refinery. The strains were confirmed by biochemical tests and 16S rRNA, which were Stenotrophomonas maltophilia (two strains), Thermomonas koreensis (three strains), Achromobacter (two strains), Pseudomonas stutzeri (one strain), Azospirillum brasilense (one strain) and Brevibacillus brevis (one strain). The isolate strains can be applied as a bacterial consortium for purification of polluted soil with high levels of PAHs. [ABSTRACT FROM AUTHOR]

In 2017, we conducted a field experiment to test the influence of a mixture of two plant growth-promoting bacteria (Pseudomonas fluorescens and Azospirillum brasilense) on the yield of three potato varieties. In addition, the influence of the mixture on potato susceptibility to infection by the pseudofungus Phytophthora infestans and fungus Alternaria solani and to attacks by the Colorado potato beetle (Leptinotarsa decemlineata) was investigated. It was the first experiment of its kind in Europe. In the unusually hot and dry year, a positive influence on the yield (17%-31%) was found in all three varieties when the tubers were soaked in the bacterial mixture prior to sowing. We observed no significant differences in potato resilience/susceptibility to harmful organisms among the different treatments (soaked tubers, sprayed tubers, untreated tubers); however, there were significant differences in the productivity between the tuber varieties. The results of our research indicate the bacterial mixture used in this study has a high potential to support satisfactory potato yields under dry conditions and under low levels of infection by foliar fungal diseases and attacks by foliar insects. [ABSTRACT FROM AUTHOR]

The field experiment was conducted to study the effect of conventional chemical fertilizer (urea),conventional biofertilizers (charcoal based) and organic matrix entrapped biofertilizer; (OMEB: a consortium ofAzotobacter chroococcum, Azospirillum brasilenseandPseudomnas putidaentrapped with clay soil, neem leaves, and cow dung in ratio of 1:1:1 and 15% saresh (plant gum of Acacia sp.) in various doses on growth parameters ofRauwolfia serpentinain terms of root length, shoot length, number of leaves, number of roots and fresh and dry weight of roots and shoots. Replacement of conventional chemical fertilizer by the consortium of biofertilizers (un-entrapped) increased plant growth in a dose dependent manner up to triple dose of the recommended dose (RD) of biofertilizers (1.80 kg ha-1). This increase in plant growth was not up to the level which appeared in the application of RD of urea. Entrapment of the same biofertilizers in an organic matrix mentioned above enhanced the plant growth similar to that observed for urea. The percentage increase of 9.57 and 7.54 in fresh weight (FW) and 11.93 and 11.12% in dry weight (DW) of shoot and 17.94 and 37.87% in FW of roots and 31.90 and 50.08% in DW of roots were recorded in 75 days old plant by the application of OMEB- triple dose over the conventional biofertilizers triple dose and recommended dose of urea. Conventional biofertilizers enhanced the availability of nitrate, nitrite and phosphate in the roots and leaves of the plant over application of urea as well as conventional biofertilizers. This formulation also increased alkaloid contents of in the roots of this plant. Microbial population of soil was also improved indicating enhanced soil fertility with application of OMEB. The results indicate that replacement of chemical fertilizers with microbial biofertilizers is possible with application of higher dose of biofertilizers entrapped into the organic matrix for the cultivation of medicinal plants like R. serpentina. [ABSTRACT FROM AUTHOR]

Zea maysL. ssp.mexicana(teosinte) is a naturally occurring grass related to maize. The two plants have developed foliar fungal diseases that can be controlled with beneficial bacterial antagonists. While the beneficial effects on stem and root development of the application of bacteria of the genusAzospirillumis widely known, the effects of the bacteria on the control of the phytopathogenic fungi associated with teosinte leaves and seeds are unknown. Bacterium of the speciesA. brasilensethat present acetylene reducing activity, siderophore production and the ability to antagonise pathogenic fungiin vitroandin vivoin teosinte plants were selected for this study, in which the incidence of fungal diseases caused byAlternaria, BipolarisandFusariumwere reduced in plants. Furthermore, biomass (root and stem) production increased, improving teosinte plant health in greenhouse and field conditions. [ABSTRACT FROM PUBLISHER]

The purposes of this study were evaluate the effects of biofertilizers inoculation on growth indices, yield and radiation use efficiency (RUE) in black cumin under Mashhad climatic conditions. This field experiment was carried out based on a randomized complete block design with three replications. This experiment was performed at Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during two growing seasons 2007–2008 and 2008–2009. Treatments were (A) Azotobacter paspali, (B)Azospirillum brasilense, (C)Rhizophagus irregularis, A + C, B + C, A + B, A + B + C and control. In all treatments, except control, 100 g of seeds were inoculated with15 mg of each biofertilizer. Results indicated that leaf area index (LAI) and accumulative dry matter (DM) showed an increasing trend up to 1863°Cd and a short declining trend afterwards. The relation between accumulative DM and absorbed photosynthesis active radiation (PARa) was linear. Radiation use efficiency (RUE) fluctuated from 0.55 gMJ−1(control) to 0.89 gMJ−1(B+C). Inoculation with biofertilizers enhanced root development and hence availability of moisture and nutrients, particularly nitrogen and phosphorus. Since these ecological fertilizers produce many growth regulators for the plant which promote LAI and accumulative DM and therefore yield, PARa and RUE enhanced. [ABSTRACT FROM AUTHOR]

Plant growth–promoting bacteria may play an important role on rice development; however, its interaction with different genotypes is still uncertain. This work aimed to assess the effect of inoculation ofAzospirillum brasilenseAbV5 strain on the agronomical performance of different rice cultivars under field conditions during two consecutive years and to determine the response of rice cultivars to indole-acetic acid (IAA) rates under in vitro conditions using for both conditions a randomized block design. Field experiments evaluated the productivity components and grain yield of inoculated and noninoculated cultivars and in vitro assays monitored the plantlet growth under different IAA rates. Field experiments showed that the general average grain yield of rice cultivars inoculated withA. brasilenseAbV5 strain was significantly greater. Fifty percent of the evaluated cultivars had statistically significant increase in yield varying from 40 to 108 percent upon inoculation withA. brasilenseAbV5 strain, while 35 percent showed no significant change in yield (−6 to −28 percent). In vitro assays showed rate- and cultivar-dependent responses of upland rice to exogenous IAA. These results show a cultivar-dependent response of rice to inoculation withA. brasilenseAbV5 strain, which can be related with IAA production by AbV5 strain. [ABSTRACT FROM PUBLISHER]

The exposure ofAzospirillum brasilensecarbohydrate epitopes was investigated by electro-optical analysis of bacterial cell suspensions. To study changes in the electro-optical (EO) properties of the suspensions, we used antibodies generated to the complete lipopolysaccharide ofA. brasilensetype strain Sp7 and also antibodies to the smooth and rough O polysaccharides of Sp7. After 18 hr of culture growth, the EO signal of the suspension treated with antibodies to smooth O polysaccharide was approximately 20% lower than that of the suspension treated with antibodies to complete lipopolysaccharide (control). After 72 hr of culture growth, the strongest EO signal was observed for the cells treated with antibodies to rough O polysaccharide (approximately 46% greater than the control), whereas for the cells treated with antibodies to smooth O polysaccharide, it was much lower (approximately 23% of the control). These data were confirmed by electron microscopy. The results of the study may have importance for the rapid evaluation of changes in lipopolysaccharide form in microbial biotechnology, when the antigenic composition of the bacterial surface requires close control. [ABSTRACT FROM PUBLISHER]

Inoculation of wheat and corn grains with formulations of Azospirillum brasilense significantly increased seedling growth parameters of wheat and corn compared to untreated controls. Inoculation with Azospirillum and supplemental Trichoderma harzianum free or coimmobilized in calcium alginate resulted in significant increase in all plant growth parameters in addition to improving plant nutrient-content [phosphorus (P), potassium (K), and calcium (Ca)]. Grain treatments with T. harzianum alone or in a combination with A. brasilense were protected from invasion by Fusarium in a pot experiment. Nitrogen (N) fixation was investigated by A. brasilense free or double inoculated with T. harzianum in soil amended with different C-sources; also, phosphate solubilization was tested by these two organisms. Single and double inoculation with A. brasilense and/or T. harzianum improved wheat yield growth parameters in addition to seed protein; therefore, immobilized and coimmobilized formulations could be used as biofertilizer and biopesticide, and might be recommended to avoid the extensive use of the agrochemicals. [ABSTRACT FROM AUTHOR]

This article reports the first preparation of miniantibodies to Azospirillum brasilense Sp245 surface antigens by using a combinatorial phage library of sheep antibodies. The prepared phage antibodies were used for the first time for lipopolysaccharide and flagellin detection by dot assay, electro-optical analysis of cell suspensions, and transmission electron microscopy. Interaction of A. brasilense Sp245 with antilipopolysaccharide and antiflagellin phage-displayed miniantibodies caused the magnitude of the electro-optical signal to change considerably. The electro-optical results were in good agreement with the electron microscopic data. This is the first reported possibility of employing phage-displayed miniantibodies in bacterial detection aided by electro-optical analysis of cell suspensions. [ABSTRACT FROM PUBLISHER]

Soybean is widely cultivated in Argentina, and there are areas where a significant degree of nodulation by soil indigenous rhizobia prevents improved nitrogen nutrition. The aim of this study was to determine the effect of inoculation with selected strains of Azospirillum brasilense on the production of different varieties of soybean cultivated in Tucumán, Argentina. Azospirillum was selected on the basis of the extent of colonization of soybean roots, nitrogenase activity, and auxin production. We found that wild strains of rhizobia were not affected by inoculation with Azospirillum and increased grain yield and nodulation, and nitrogen fixation was largest. This research provides an alternative for soybean production. [ABSTRACT FROM PUBLISHER]

The effect of Azospirillum brasilense Sp245 on the micropropagation of three fruit rootstocks: Mr.S 2/5 plum (Prunus cerasifera×P. spinosa), GF 677 hybrid (Prunus persica×P. amigdalus), and MM 106 apple (Northen Spy×M1) was assessed. Rooted shoots were treated with 3×107 of Sp245 cells during transplantation from in vitro cultures to the acclimatization phase. After 60 days, growth parameters were positively affected by Sp245 inoculum. In the case of Mr.S 2/5, an increase in rootstock stem length and node number by 37% and 42%, respectively, compared to the control was noted. In the case of GF 677, the bacterial inoculum increased stem length and node number by up to the 75% and 65%, respectively, compared to the control. The inoculum did not exert on MM 106 for both parameters suggesting that the effects of Sp245 could depend on a specific clone-microbe association. In all cases, however, a higher vigor, consistent with a wider leaf area, was present in the inoculated plantlets demonstrating that the use of Azospirillum can significantly contribute to optimize plant performance during the phase of adaptation of plants to post-vitrum conditions. [ABSTRACT FROM AUTHOR]

A modified approach was adopted to develop co-flocs consisting of Azospirillum brasilense MTCC-125 and Pseudomonas fluorescens MTCC-4828. The results of our study revealed that both Azospirillum and Pseudomonas strains exhibited a higher survivability when embedded in the flocs. The survivability of the strains in co-floc was found to be higher when compared to the log phase vegetative cells in different inoculant carriers, spermosphere rhizoplane and rhizosphere. The co-floc treatment has also significantly increased the germination percentage and vigour index of rice. In the present study flocculation was found to play a major role in enhancing adhesion of both the strains to rice roots. The co-flocs were studied for their efficiency to induce resistance in rice crop against rice blast. The relative role of Azospirillum and Pseudomonas co-flocs in the induction of resistance against the phytopathogen was evaluated. It was found that when the activities of polyphenol oxidase, peroxidase and phenol were high and when the relative amounts of the sugars were low, the disease infestation was less and vice versa. The association of these compounds strongly implies their role as casual agents of induced resistance against Pyricularia oryzae. [ABSTRACT FROM AUTHOR]

An investigation was conducted to study the effect of biofertilisers (Glomus fasciculatum, Azospirillum brasilense, Azotobacter chroococcum and Micro Phos) and pesticides (carbofuran and bavistin) on the management of root-rot and root-knot disease complex of balsam. The individual application of biofertilisers (G. fasciculatum, A. brasilense and A. chroococcum) significantly improved the plant growth parameters viz., length, dry weight and number of flowers compared to untreated-uninoculated plants. The simultaneous inoculation of plant with Meloidogyne javanica and Macrophomina phaseolina in the pots treated with either of the biofertilisers (G. fasciculatum, A. brasilense and A. chroococcum) and pesticides (carbofuran/bavistin) significantly improved the plant growth parameters and reduced the reproduction factor, number of galls and intensity of root-rot compared to untreated-inoculated plants. On the other hand, the plants treated with Micro Phos neither significantly improved the plant growth parameters nor reduced the reproduction factor, number of galls and intensity of root-rot. Among the biofertilisers and pesticides, carbofuran was found to be the most effective in the management of disease complex of balsam followed by bavistin, G. fasciculatum, A. brasilense and A. chroococcum. [ABSTRACT FROM AUTHOR]

Evolution of symbiotic plant-microbe interactions has provided mankind a powerful and environment-friendly means to increase yield of agricultural crops. Here, we report that some azide resistant mutants of two microbial strains can significantly enhance the productivity of cotton varieties, as an attractive and cheap biological substitute of chemical fertilizers, for improved yield of an important cash crop, without any untoward impacts. Sodium azide resistant mutants were isolated from each strain of Azospirillum brasilense and Acetobacter diazotrophicus on different concentrations of sodium azide ranging from 5–60µg/ml. These azide resistant mutants were assessed for their performance on cotton (varieties H-117, HD-123) for various parameters. Inoculation of cottonseeds with mutants obtained better results than inoculation with their respective parental strains. Azide resistant mutants, when used as biofertilizers, showed increased plant height, early flowering, more yield, and high biomass and total nitrogen content. They also increased, in cotton genotypes, the indole acetic acid production and ammonia excretion due to high nitrogenase activity. [ABSTRACT FROM AUTHOR]