IDENTIFICATION AND QUANTIFICATION OF WHEAT ROOTS FLAVONOIDS INOCULATED WITH NATIVE RHIZOBACTERIA

In this study, we identified the presence and quantity of flavonoids produced in wheat roots inoculated with rhizobacteria. Our goal is to confirm the efficiency of standard isolates and show new strains with biotechnological potential to promote plant growth. The experiment was carried out with different isolates under inoculation in the following situations: T1-Azospirillum brasiliense; T2-Herbaspirillum seropedicae; T3-Azospirillum brasiliense and Herbaspirillum seropedicae co-inoculation; T4-native Enterobacter sp. nº 203; T5- native Enterobacter sp. nº 208; T6-native Enterobacter sp. nº 493; T7-Control only under nitrogen fertilization (N+); T8-Control without nitrogen (N-) and bacterial inoculation. Agronomic characteristics were assessed after 42 days of inoculation. Identification and quantification of flavonoids were carried out through HPLC, using an analytical curve with four standards based on Coumarin, Quercetin, Isoflavone and Rutin. Regarding the production of total flavonoids, two (203 and 493) out of the three native strains we tested were statistically significant, exceeding the values obtained from the inoculation of standard strains, which presented association with grasses (Azopirilum e Herbaspirillum). Standard bacteria, when inoculated in isolation, presented, along with those that received N+ treatment, the highest values for length and root and aerial part dry mass. New studies need to be carried out in order to confirm the technological use of these native strains as inoculant, as these bacteria may contribute to Biological Nitrogen Fixation (BNF) in wheat culture, either by competition or synergism.

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Examining the Effects of the Nitrogen Environment on Growth and N2-Fixation of Endophytic Herbaspirillum seropedicae in Maize Seedlings by Applying 11C Radiotracing

Microorganisms ◽

10.3390/microorganisms9081582 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1582

Author(s):

Spenser Waller ◽

Stacy L. Wilder ◽

Michael J. Schueller ◽

Alexandra B. Housh ◽

Stephanie Scott ◽

...

Keyword(s):

Plant Growth ◽

Root Colonization ◽

Growth Promotion ◽

Nitrogenase Activity ◽

Growth Conditions ◽

Significant Inhibition ◽

Cereal Crops ◽

Herbaspirillum Seropedicae ◽

Promote Plant Growth ◽

Biological Nitrogen

Herbaspirillum seropedicae, as an endophyte and prolific root colonizer of numerous cereal crops, occupies an important ecological niche in agriculture because of its ability to promote plant growth and potentially improve crop yield. More importantly, there exists the untapped potential to harness its ability, as a diazotroph, to fix atmospheric N2 as an alternative nitrogen resource to synthetic fertilizers. While mechanisms for plant growth promotion remain controversial, especially in cereal crops, one irrefutable fact is these microorganisms rely heavily on plant-borne carbon as their main energy source in support of their own growth and biological functions. Biological nitrogen fixation (BNF), a microbial function that is reliant on nitrogenase enzyme activity, is extremely sensitive to the localized nitrogen environment of the microorganism. However, whether internal root colonization can serve to shield the microorganisms and de-sensitize nitrogenase activity to changes in the soil nitrogen status remains unanswered. We used RAM10, a GFP-reporting strain of H. seropedicae, and administered radioactive 11CO2 tracer to intact 3-week-old maize leaves and followed 11C-photosynthates to sites within intact roots where actively fluorescing microbial colonies assimilated the tracer. We examined the influence of administering either 1 mM or 10 mM nitrate during plant growth on microbial demands for plant-borne 11C. Nitrogenase activity was also examined under the same growth conditions using the acetylene reduction assay. We found that plant growth under low nitrate resulted in higher nitrogenase activity as well as higher microbial demands for plant-borne carbon than plant growth under high nitrate. However, carbon availability was significantly diminished under low nitrate growth due to reduced host CO2 fixation and reduced allocation of carbon resources to the roots. This response of the host caused significant inhibition of microbial growth. In summary, internal root colonization did little to shield these endophytic microorganisms from the nitrogen environment.

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Nodulation and Development of Soybean Submitted to Inoculation With Bradyrhizobium japonicum and Phosphorus Doses

Journal of Agricultural Science ◽

10.5539/jas.v10n12p321 ◽

2018 ◽

Vol 10 (12) ◽

pp. 321 ◽

Cited By ~ 1

Author(s):

Erica Chaves ◽

Rubson da Costa Leite ◽

Thalita Rodrigues Silva ◽

Thayny Alves Viana ◽

Tatiane de Sousa Cruz ◽

...

Keyword(s):

Nitrogen Fixation ◽

Experimental Design ◽

Bradyrhizobium Japonicum ◽

Phosphate Fertilizer ◽

Dry Mass ◽

Root Number ◽

Phosphate Fertilization ◽

Soybean Plants ◽

Biological Nitrogen ◽

Plant Dry Mass

Among the several factors that may influence nodulation and the efficiency of biological nitrogen fixation for soybean plants, nutrient availability is among the most important. This study aimed to evaluate the inoculation with Bradyrhizobium japonicum and doses of phosphorus on the development of soybean in a Vertisol, in Tocantins. The experimental design was completely randomized in a 4 × 2 factorial scheme, with four replications. Four doses of phosphate fertilization (0, 100, 200, and 300 kg ha-1 P2O5) were studied, combined with two inoculation treatments with Bradyrhizobium japonicum (inoculated and not inoculated). The following variables were evaluated: plant height, stem diameter, nodules per plant, dry mass of nodules, dry mass of plant, dry mass of root, number of pods and number of grains per pod. Under greenhouse conditions and soil with good availability of phosphorus, there is no influence of the doses on the inoculation with Bradyrhizobium japonicum. Soils with good availability of phosphorus have low response to the application of phosphate fertilizer.

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Competition, Nodule Occupancy, and Persistence of Inoculant Strains: Key Factors in the Rhizobium-Legume Symbioses

Frontiers in Plant Science ◽

10.3389/fpls.2021.690567 ◽

2021 ◽

Vol 12 ◽

Author(s):

Marcela Mendoza-Suárez ◽

Stig U. Andersen ◽

Philip S. Poole ◽

Carmen Sánchez-Cañizares

Keyword(s):

Nitrogen Fixation ◽

Current Knowledge ◽

Local Environment ◽

Nitrogen Fertilizers ◽

Superior Performance ◽

Nodule Occupancy ◽

Inoculant Strain ◽

Native Strains ◽

Biological Nitrogen ◽

Rhizobial Inoculants

Biological nitrogen fixation by Rhizobium-legume symbioses represents an environmentally friendly and inexpensive alternative to the use of chemical nitrogen fertilizers in legume crops. Rhizobial inoculants, applied frequently as biofertilizers, play an important role in sustainable agriculture. However, inoculants often fail to compete for nodule occupancy against native rhizobia with inferior nitrogen-fixing abilities, resulting in low yields. Strains with excellent performance under controlled conditions are typically selected as inoculants, but the rates of nodule occupancy compared to native strains are rarely investigated. Lack of persistence in the field after agricultural cycles, usually due to the transfer of symbiotic genes from the inoculant strain to naturalized populations, also limits the suitability of commercial inoculants. When rhizobial inoculants are based on native strains with a high nitrogen fixation ability, they often have superior performance in the field due to their genetic adaptations to the local environment. Therefore, knowledge from laboratory studies assessing competition and understanding how diverse strains of rhizobia behave, together with assays done under field conditions, may allow us to exploit the effectiveness of native populations selected as elite strains and to breed specific host cultivar-rhizobial strain combinations. Here, we review current knowledge at the molecular level on competition for nodulation and the advances in molecular tools for assessing competitiveness. We then describe ongoing approaches for inoculant development based on native strains and emphasize future perspectives and applications using a multidisciplinary approach to ensure optimal performance of both symbiotic partners.

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Soil humidity as a productive conditioner of soybean culture through inoculation, co-inoculation and rooting

Australian Journal of Crop Science ◽

10.21475/ajcs.20.14.06.p2133 ◽

2020 ◽

pp. 932-939

Author(s):

Evandro Ademir Deak ◽

Thomas Newton Martin ◽

Glauber Monçon Fipke ◽

Jessica Deolinda Leivas Stecca ◽

Vinícius dos Santos Cunha

Keyword(s):

Azospirillum Brasilense ◽

Dry Mass ◽

Sowing Dates ◽

Soybean Plants ◽

The Times ◽

The Many ◽

High Yields ◽

Biological Nitrogen ◽

Measured Water ◽

Soybean Nodulation

In the soybean crop, the practice of inoculation is crucial for producing high yields. This is because biological nitrogen fixation (BNF) is the main supplier of the nutrient demand for this crop. However, a few environmental variables can also greatly influence the survival of the bacteria that control this process. In this context, the present work was performed to confirm the many ways in which soil moisture affects this process. In the field, we conducted two experiments at the times of the two sowing dates, 11/24/2015 and 12/17/2015, adopting the factorial 7 x 2 design, with four replications. The inoculation treatments included, non-inoculated (NI); not inoculated along with the nitrogen supplied at the 200 kg ha-1 (NI+N) dosage; inoculation with Bradyrhizobium [I (Brady)]; root enhancers (R); inoculation with Bradyrhizobium + root enhancers (I+R); co-inoculation with Bradyrhizobium + Azospirillum brasilense (I+Azo); co-inoculation with Bradyrhizobium + Azospirillum brasilense + root enhancers (I+Azo+R). The second factor included was the use or absence of a water jet (200 L ha-1) directed onto the seeds in the sowing furrow. Then estimations of the initial establishment of the plants, nodulation, and productivity components were measured. Water supplied to the sowing furrow had no effect on soybean nodulation and yield components. Co-inoculation promoted nodulation in soybean plants, particularly in dry mass of the nodules and number of nodules per plant.

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Does inoculation with Rhizobium tropici and nitrogen fertilization increase chickpea production?

Ciência e Agrotecnologia ◽

10.1590/1413-7054202044016520 ◽

2020 ◽

Vol 44 ◽

Author(s):

Maria Nilfa Almeida Neta ◽

Rodinei Facco Pegoraro ◽

Regynaldo Arruda Sampaio ◽

Cândido Alves da Costa ◽

Luiz Arnaldo Fernandes ◽

...

Keyword(s):

Nitrogen Fertilization ◽

Mass Number ◽

Dry Mass ◽

Control Treatment ◽

Rhizobium Tropici ◽

Agronomic Efficiency ◽

Tropical Regions ◽

Tropical Conditions ◽

Chlorophyll Index ◽

Biological Nitrogen

ABSTRACT Studies related to nitrogen fertilization and biological nitrogen fixation in the increase of chickpea production are considered scarce in tropical regions. This work aimed to evaluate the inoculation with Rhizobium tropici, and nitrogen fertilization, under irrigated tropical conditions, on the development of chickpea in low and high content of soil organic matter (SOM). The experimental design was in randomized blocks, with four replications, in a 2 x 6 factorial scheme. Treatments, consisted of the presence and absence of inoculation with R. tropici, and six N doses (0, 25, 50, 75, 100, and 125 kg ha-1) in the form of urea. The study was divided into two areas with distinct contents of SOM. In the area with the lowest content of SOM (3.55 dag kg-1), the inoculation with R. tropici or the fertilization with 125 kg ha-1 N increased the leaf content of nutrients (N, K, Mg, and P) and grain mass per plant, 100-grain mass, number of pods with two grains, dry mass of leaves, branches, chlorophyll index, and relative agronomic efficiency. Thus, the yield was increased in 65%, compared to the control treatment, recommending the application of 100 to 125 kg ha-1 of N with or without R. tropici. In the area with the highest content of SOM (7.37 dag kg-1), the inoculation with R. tropici provided a higher grain mass per plants, number of pods with one gain, dry mass of leaves, total dry mass, and chlorophyll index; nitrogen fertilization increased the leaf content of N and the chlorophyll index, although neither factor interfered with the yield, and are not recommended. Such results indicate the dependence of the nitrogen fertilization and inoculation with Rhizobium on the natural availability of N in the SOM.

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609 Effects of CO2 Concentration and Photoperiod on Growth of Lettuce under High Humidity Conditions

HortScience ◽

10.21273/hortsci.35.3.502b ◽

2000 ◽

Vol 35 (3) ◽

pp. 502B-502

Author(s):

Yoshiaki Kitaya ◽

Tsutomu Moriya ◽

Makoto Kiyota

Keyword(s):

Relative Humidity ◽

Co2 Concentration ◽

Dry Mass ◽

Plant Production ◽

Photon Flux ◽

High Humidity ◽

Commercial Plant ◽

Fluorescent Lamps ◽

Promote Plant Growth ◽

Supplemental Lighting

Supplemental lighting and CO2 enrichment have been employed to promote plant growth in commercial plant production in greenhouses. In a semi-closed plant production system with a large number of plants at a high density, the relative humidity in the air around growing plants could be in excess of 80%. This research was initiated to determine the effects of CO2 concentration and photoperiod on the growth of plants under relatively high humidity conditions. In the experiment, lettuce plants were grown for 13 days under eight combinations of two CO2 levels (CO2, 0.38 and 0.76 mmol·mol-1), two photoperiods (PP, 16 and 24 h/day), and two relative humidity levels (RH, 80% and 90%) in growth chambers. The air temperature was 25 °C. Plants were illuminated with fluorescent lamps at a photosynthetic photon flux of 0.23 mmol·m-2·s-1. The dry mass of lettuce shoots (leaves and stems) grown in 0.76 mmol·mol-1 CO2, 24 h/day PP, and 80% to 90% RH was greatest in all treatments and was five times the least value obtained in 0.38 mmol·mol-1 CO2, 16 h/day PP and 90% RH. The dry mass of lettuce shoots decreased to 40% as RH increased from 80% to 90 % under 0.38-0.76 mmol·mol-1 CO2 and 16 h/day PP. Growth suppression by excess humidity was less significant in longer PP and higher CO2. Supplemental lighting and CO2 enrichment would be more effective for promoting growth of plants grown under higher humidity conditions.

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Initial performance of maize in response to NPK fertilization combined with Herbaspirillum seropedicae

Revista CERES ◽

10.1590/s0034-737x2012000600015 ◽

2012 ◽

Vol 59 (6) ◽

pp. 841-849 ◽

Cited By ~ 6

Author(s):

Marihus Altoé Baldotto ◽

Lílian Estrela Borges Baldotto ◽

Rogério Batista Santana ◽

Cláudio Roberto Marciano

Keyword(s):

Dry Mass ◽

Plant Growth Promoting Bacteria ◽

Initial Growth ◽

Herbaspirillum Seropedicae ◽

Biotechnological Approach ◽

Plant Growth Promoting ◽

Maize Plants ◽

Growth Promoting ◽

Treatment Application ◽

Npk Fertilization

The inoculation with plant growth-promoting bacteria can be a technological approach useful for increasing the production of maize. The objective of this study was to evaluate the initial performance of maize in response to application of doses of NPK combined with the inoculation of the diazotrophic bacteria Herbaspirillum seropedicae in an greenhouse experiment. The experiment consisted of six fertilizer levels: 0, 25, 50, 75, 100 and 200% of the recommended dose of NPK applied to maize inoculated and non-inoculated with H. seropedicae. At 30 days after the treatment application, the growth characteristics and nutritional status of the plants were evaluated. Plant development was influenced by fertilization, but it was enhanced by combination with the bacteria, which resulted in significant increases in the dry mass of shoots (7%) and leaf area (9%) when compared with non-inoculated plants. The results showed increases in the concentration of N (11%), P (30%) and K (17%) of maize plants in response to bacterial inoculation together with NPK compared with plants that were applied fertilize only. The greater consistency and stability response of the host plant to bacterization in the presence of chemical fertilizer indicate a promissory biotechnological approach for improving the initial growth and adaptation of maize to the cultivation environment.

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Growth rate and nutritional status of an organic coffee cropping system

Scientia Agricola ◽

10.1590/s0103-90162005000200008 ◽

2005 ◽

Vol 62 (2) ◽

pp. 138-144 ◽

Cited By ~ 10

Author(s):

Marta dos Santos Freire Ricci ◽

Bruno José Rodrigues Alves ◽

Simone Cordeiro de Miranda ◽

Fabio Freire de Oliveira

Keyword(s):

Nitrogen Fixation ◽

Nutritional Status ◽

Biological Nitrogen Fixation ◽

Plant Biomass ◽

Dry Mass ◽

Organic Fertilizers ◽

Total N ◽

Sunn Hemp ◽

Biological Nitrogen ◽

Organic Coffee

In view of the low N concentration in organic fertilizers, it is necessary to use high rates of such fertilizers to attend coffee crop requirements. Hence, N is the most limiting nutrient for organic coffee production. The objective of this work was to evaluate the influence of sunn hemp (Crotalaria juncea) organic fertilization on the growth and nutritional status of coffee cultivars, as well as to quantify plant biomass and N input derived from biological nitrogen fixation, and their effect on soil chemical characteristics. The experiment consisted of six coffee (Coffea arabica) cultivars intercropped with and without sunn hemp sown in November 2001 and pruned at mid-height 76 days later. At 175 days, the standing biomass of the legume was cut, measuring dry mass, total N, P, K, Ca, Mg, and 15N natural abundance, resulting 16 t ha-1 of dry mass and the recycling of 444, 21, 241, 191, and 44 kg ha-1 of N, P, K, Ca, and Mg, respectively. Cultivars 'Obatã' and 'Catuaí Vermelho' presented the highest growth rates in terms of plant height, while cultivars 'Icatu' and 'Oeiras' presented the lowest rates. Biological nitrogen fixation associated to the legume introduced more than 200 kg ha-1 of N, which is a demonstration that N fertilization in organic cropping systems is a valuable alternative. Intercropping lead to a constant coffee leaf N content during the entire cropping cycle, contrary to what was observed in plots grown without sunn hemp.

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Evaluation of Trichoderma spp. Isolates in Cocoa Seed Treatment and Seedling Production

Plants ◽

10.3390/plants10091964 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1964

Author(s):

Willian Nogueira de Sousa ◽

Nayane Fonseca Brito ◽

Cristina Aledi Felsemburgh ◽

Thiago Almeida Vieira ◽

Denise Castro Lustosa

Keyword(s):

Plant Growth ◽

Seed Treatment ◽

Plant Root ◽

Soil Fungus ◽

Dry Mass ◽

Seedling Production ◽

Trichoderma Spp ◽

Germination Speed ◽

Promote Plant Growth ◽

Number Of Leaves

Isolates of Trichoderma spp., a soil fungus, has been used to control diseases and promote plant growth, reducing the use of chemicals in the production of seedlings of different plant species. We evaluated the effect of some Trichoderma spp. isolates on seed treatment and seedling production of Theobromacacao. Five isolates from the Amazon region were tested. In laboratory, the following variables were evaluated for seed treatments: germination, germination speed index, radicle and hypocotyl lengths, and fungi incidence. In nursery, the following forms of application were tested: via seeds; in the substrate at pre-planting; monthly in post-planting substrate, and also their combination. The following was evaluated: height, diameter, number of leaves, root length, leaf area, and shoot dry mass and root system. Inoculation with Trichoderma increased the length of the radicle and hypocotyl and showed no fungi in the seeds. In seedlings, some treatments increased height and plant root dry mass. The use of Trichoderma was beneficial for seeds and appeared favorable for T. cacao production.

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Can inoculation with diazotrophic bacteria decrease the productivity loss of defoliated Vigna unguiculata (L.) Walp?

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v25n3p189-196 ◽

2021 ◽

Vol 25 (3) ◽

pp. 189-196

Author(s):

Caliane da S. Braulio ◽

Leonardo F. L. da Silva ◽

Claudemir S. da Silva ◽

Andreza de J. Correia ◽

Juan M. A. Rocabado ◽

...

Keyword(s):

Nutrient Concentration ◽

Productivity Loss ◽

Dry Mass ◽

N Fertilization ◽

Vegetative Stage ◽

Plant Tolerance ◽

Diazotrophic Bacteria ◽

Bacterial Inoculation ◽

N Sources ◽

The Mean

ABSTRACT The objective of this study was to evaluate the effect of artificial defoliation on vegetative and productive stages of cowpea inoculated with diazotrophic bacteria, in two experiments. The first experiment was performed in a greenhouse with 5 × 5 factorial (five defoliation percentages and five N sources), with four repetitions. N sources consisted of bacterial inoculation with strains INPA 03-11B, UFLA 03-84, UFRB FA34C2-2, and two control treatments: i - with N fertilization and ii - blank control, without N fertilization and without inoculation. The second experiment was performed in the field, in a 3 × 5 factorial scheme, with three repetitions. Treatments consisted of three N sources: with N fertilization, with bacterial strain INPA 03-11B that was selected in the first experiment, and five percentages of artificial defoliation. Defoliation percentages for both experiments were 0, 25, 50, 75, and 100%. Artificial defoliation during the vegetative stage caused reduction in the dry mass of bacterial nodules. Inoculation increased plant tolerance to defoliation and enhanced grain nutrient concentration (N and P). Inoculation with the strain INPA 03-11B allowed cowpea plants to tolerate 50% defoliation in the vegetative stage. The mean productivity of cowpea was reduced under > 50% defoliation during the productive stage; therefore, control of defoliating pests until the productive stage is not necessary under field conditions.

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