scholarly journals Valorization of Lignin as an Immobilizing Agent for Bioinoculant Production using Azospirillum brasilense as a Model Bacteria

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4613
Author(s):  
Victor Rogelio Tapia-Olivares ◽  
Eimy Alejandra Vazquez-Bello ◽  
Efrén Aguilar-Garnica ◽  
Froylán M.E. Escalante
Keyword(s):  
Azospirillum Brasilense ◽  
Low Cost ◽  
Fluorescent Microscopy ◽  
Plant Stress ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Cells ◽  
Practical Applications ◽  
Agricultural Applications ◽  
Plant Growth Promoting ◽  
The Stability

Plant growth-promoting bacteria (PGPB) have been largely considered as beneficial in harsh and limiting environments given their effects on alleviating plant stress. For practical applications, most of the PGPB are prepared in immobilization matrices to improve the stability and benefits of bacteria. Despite the long list of immobilizing agents/carriers tested to date, a long list of desired requirements is yet to be achieved. Here, lignin stands as a scarcely tested immobilizer for bioinoculants with great potential for this purpose. The aim of this work was to demonstrate the feasibility of lignin as a carrier of the nitrogen-fixing Azospirillum brasilense. These bacteria were cultured in liquid media with recovered organosolv lignin added for bacterial immobilization. Then, lignin was recovered and the immobilized biomass was quantified gravimetrically by DNA extraction and serial dilution plating. Fluorescent microscopy as well as Congo red agar plating showed the immobilization of the bacterial cells in the lignin matrix and crystal violet dyeing showed the biofilms formation in lignin particles. A high number of cells were counted per gram of dried lignin. Lignin can be readily used as low-cost, health-safe bioinoculant carrier to be used in soil and agricultural applications.

Co-inoculation of maize with Azospirillum brasilense and Rhizobium tropici as a strategy to mitigate salinity stress

2018 ◽  
Vol 45 (3) ◽  
pp. 328 ◽  
Author(s):  
Josiane Fukami ◽  
Clara de la Osa ◽  
Francisco Javier Ollero ◽  
Manuel Megías ◽  
Mariangela Hungria
Keyword(s):  
Salinity Stress ◽  
Azospirillum Brasilense ◽  
Plant Stress ◽  
Saline Stress ◽  
Plant Growth Promoting Bacteria ◽  
Rhizobium Tropici ◽  
Negative Effects ◽  
Expression Of Genes ◽  
Plant Growth Promoting ◽  
Leaves And Roots

Plants are highly affected by salinity, but some plant growth-promoting bacteria (PGPB) may trigger induced systemic tolerance (IST), conferring protection against abiotic stresses. We investigated plant mechanisms under saline stress (170 mM NaCl) when maize was singly or co-inoculated with Azospirillum brasilense strains Ab-V5 and Ab-V6 and Rhizobium tropici strain CIAT 899. Under greenhouse conditions, plants responded positively to inoculation and co-inoculation, but with differences between strains. Inoculation affected antioxidant enzymes that detoxify reactive oxygen species (ROS) – ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD) – mainly in leaves. Proline contents in leaves and roots and malondialdehyde (MDA) in leaves – plant-stress-marker molecules – were significantly reduced due to the inoculation, indicating reduced need for the synthesis of these molecules. Significant differences were attributed to inoculation in the expression of genes related to antioxidant activity, in general with upregulation of APX1, CAT1, SOD2 and SOD4 in leaves, and APX2 in roots. Pathogenesis-related genes PR1, prp2, prp4 and heat-shock protein hsp70 were downregulated in leaves and roots, indicating that inoculation with PGPB might reduce the need for this protection. Together the results indicate that inoculation with PGPB might provide protection from the negative effects of saline stress. However, differences were observed between strains, as A. brasilense Ab-V5 did not show salt tolerance, while the best inoculation treatments to mitigate saline stress were with Ab-V6 and co-inoculation with Ab-V6+CIAT 899. Inoculation with these strains may represent an effective strategy to mitigate salinity stress.

scholarly journals Development of low-cost formulations of plant growth-promoting bacteria to be used as inoculants in beneficial agricultural technologies

2019 ◽  
Vol 219 ◽  
pp. 12-25 ◽  
Author(s):  
Constanza Belén Lobo ◽  
María Silvina Juárez Tomás ◽  
Emilce Viruel ◽  
Marcela Alejandra Ferrero ◽  
María Ester Lucca
Keyword(s):  
Plant Growth ◽  
Low Cost ◽  
Plant Growth Promoting Bacteria ◽  
Agricultural Technologies ◽  
Plant Growth Promoting ◽  
Growth Promoting

scholarly journals Association of Indolebutyric Acid with Azospirillum brasilense in the Rooting of Herbaceous Blueberry Cuttings

Horticulturae ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 68 ◽  
Author(s):  
Koyama ◽  
Aparecido Ribeiro Júnior ◽  
Mariani Zeffa ◽  
Tadeu Faria ◽  
Mitsuharu Saito ◽  
...  
Keyword(s):  
Root Length ◽  
Azospirillum Brasilense ◽  
Dry Mass ◽  
Plant Growth Promoting Bacteria ◽  
Indolebutyric Acid ◽  
Rooted Cuttings ◽  
Plant Growth Promoting ◽  
Rooting Of Cuttings ◽  
Mist Chamber ◽  
Root Growth And Development

Association between auxins and plant growth-promoting bacteria can stimulate root growth and development of fruit crop nursery plants, and can be a promising biological alternative to increase the rooting of cuttings. The objective of this study was to assess the viability of producing ‘Powderblue’ blueberry nursery plants from cuttings using different doses of indolebutyric acid (IBA) in association with Azospirillum brasilense. The following treatments were tested: 0 (control); 500 mg L−1 of IBA; 1000 mg L−1 of IBA; A. brasilense; 500 mg L−1 of IBA + A. brasilense; and 1000 mg L−1 of IBA + A. brasilense. The experimental design was completely randomized, with six treatments and four replicates, and each plot (box) consisted of 10 cuttings. The boxes were arranged in a mist chamber with an intermittent regimen controlled by a timer and solenoid valve. After 90 days, the following variables were assessed: rooted cuttings; survival of cuttings; foliar retention; sprouting; cuttings with callus; root dry mass per cutting; number of roots per cutting; and root length. It was observed that the application of IBA with the A. brasilense rhizobacteria increased the number of roots of ‘Powderblue’ blueberry cuttings, while the treatments with IBA alone and IBA 1000 mg L−1 + A. brasilense increased the root length of cuttings. However, treatments with IBA and A. brasilense had no impact on % rooted cuttings and % survival of cuttings.

A novel, green, low-cost chitosan-starch hydrogel as potential delivery system for plant growth-promoting bacteria

2018 ◽  
Vol 202 ◽  
pp. 409-417 ◽  
Author(s):  
J.J. Perez ◽  
N.J. Francois ◽  
G.A. Maroniche ◽  
M.P. Borrajo ◽  
M.A. Pereyra ◽  
...  
Keyword(s):  
Plant Growth ◽  
Delivery System ◽  
Low Cost ◽  
Plant Growth Promoting Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting

scholarly journals Mycorrhizal-Bacterial Amelioration of Plant Abiotic and Biotic Stress

2021 ◽  
Vol 5 ◽  
Author(s):  
Gustavo Santoyo ◽  
Elisa Gamalero ◽  
Bernard R. Glick
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Synergistic Effects ◽  
Plant Stress ◽  
Plant Growth Promoting Bacteria ◽  
Abiotic And Biotic Stress ◽  
Different Types ◽  
Plant Growth Promoting ◽  
Plant Microbiota ◽  
Growth Promoting

Soil microbiota plays an important role in the sustainable production of the different types of agrosystems. Among the members of the plant microbiota, mycorrhizal fungi (MF) and plant growth-promoting bacteria (PGPB) interact in rhizospheric environments leading to additive and/or synergistic effects on plant growth and heath. In this manuscript, the main mechanisms used by MF and PGPB to facilitate plant growth are reviewed, including the improvement of nutrient uptake, and the reduction of ethylene levels or biocontrol of potential pathogens, under both normal and stressful conditions due to abiotic or biotic factors. Finally, it is necessary to expand both research and field use of bioinoculants based on these components and take advantage of their beneficial interactions with plants to alleviate plant stress and improve plant growth and production to satisfy the demand for food for an ever-increasing human population.

scholarly journals Compatibility of Azospirillum brasilense with Pesticides Used for Treatment of Maize Seeds

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Mariana S. Santos ◽  
Artur B. L. Rondina ◽  
Marco A. Nogueira ◽  
Mariangela Hungria
Keyword(s):  
Plant Growth ◽  
Root Hair ◽  
Azospirillum Brasilense ◽  
Plant Protection ◽  
Plant Growth Promoting Bacteria ◽  
Root Volume ◽  
Maize Seeds ◽  
Plant Growth Promoting ◽  
Growth Promoting

Seed treatment with chemical pesticides is commonly used as an initial plant protection procedure against pests and diseases. However, the use of such chemicals may impair the survival and performance of beneficial microorganisms introduced via inoculants, such as the plant growth-promoting bacterium Azospirillum brasilense. We assessed the compatibility between the most common pesticide used in Brazil for the treatment of maize seeds, composed of two fungicides, and one insecticide, with the commercial strains Ab-V5 and Ab-V6 of A. brasilense, and evaluated the impacts on initial plant development. The toxicity of the pesticide to A. brasilense was confirmed, with an increase in cell mortality after only 24 hours of exposure in vitro. Seed germination and seedling growth were not affected neither by the A. brasilense nor by the pesticide. However, under greenhouse conditions, the pesticide affected root volume and dry weight and root-hair incidence, but the toxicity was alleviated by the inoculation with A. brasilense for the root volume and root-hair incidence parameters. In maize seeds inoculated with A. brasilense, the pesticide negatively affected the number of branches, root-hair incidence, and root-hair length. Therefore, new inoculant formulations with cell protectors and the development of compatible pesticides should be searched to guarantee the benefits of inoculation with plant growth-promoting bacteria.

scholarly journals Growth promotion of pineapple 'vitória' by humic acids and burkholderia spp. during acclimatization

2010 ◽  
Vol 34 (5) ◽  
pp. 1593-1600 ◽  
Author(s):  
Lílian Estrela Borges Baldotto ◽  
Marihus Altoé Baldotto ◽  
Luciano Pasqualoto Canellas ◽  
Ricardo Bressan-Smith ◽  
Fábio Lopes Olivares
Keyword(s):  
Humic Acids ◽  
Growth Promotion ◽  
Combined Treatment ◽  
Plant Growth Promoting Bacteria ◽  
Ex Vitro ◽  
Nutrient Contents ◽  
Planting Material ◽  
Plant Growth Promoting ◽  
The Stability

In vitro propagation of pineapple produces uniform and disease-free plantlets, but requires a long period of acclimatization before transplanting to the field. Quicker adaptation to the ex vitro environment and growth acceleration of pineapple plantlets are prerequisites for the production of a greater amount of vigorous, well-rooted planting material. The combination of humic acids and endophytic bacteria could be a useful technological approach to reduce the critical period of acclimatization. The aim of this study was to evaluate the initial performance of tissue-cultured pineapple variety Vitória in response to application of humic acids isolated from vermicompost and plant growth-promoting bacteria (Burkholderia spp.) during greenhouse acclimatization. The basal leaf axils were treated with humic acids while roots were immersed in bacterial medium. Humic acids and bacteria application improved shoot growth (14 and 102 %, respectively), compared with the control; the effect of the combined treatment was most pronounced (147 %). Likewise, humic acids increased root growth by 50 %, bacteria by 81 % and the combined treatment by 105 %. Inoculation was found to significantly increase the accumulation of N (115 %), P (112 %) and K (69 %) in pineapple leaves. Pineapple growth was influenced by inoculation with Burkholderia spp., and further improved in combination with humic acids, resulting in higher shoot and root biomass as well as nutrient contents (N 132 %, P 131 %, K 80 %) than in uninoculated plantlets. The stability and increased consistency of the host plant response to bacterization in the presence of humic substances indicate a promising biotechnological tool to improve growth and adaptation of pineapple plantlets to the ex vitro environment.

scholarly journals Quantification of Azospirillum brasilense FP2 Bacteria in Wheat Roots by Strain-Specific Quantitative PCR

2015 ◽  
Vol 81 (19) ◽  
pp. 6700-6709 ◽  
Author(s):  
Maria Isabel Stets ◽  
Sylvia Maria Campbell Alqueres ◽  
Emanuel Maltempi Souza ◽  
Fábio de Oliveira Pedrosa ◽  
Michael Schmid ◽  
...  
Keyword(s):  
Plant Growth ◽  
Quantitative Pcr ◽  
Dna Sequences ◽  
Azospirillum Brasilense ◽  
Plant Growth Promoting Bacteria ◽  
Genome Sequences ◽  
Wheat Roots ◽  
Content Type ◽  
Plant Growth Promoting ◽  
Growth Promoting

ABSTRACTAzospirillumis a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide.Azospirillum brasilensestrains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of the inoculant in the rhizosphere, which is not always achieved. The objective of this study was to develop quantitative PCR protocols for the strain-specific quantification ofA. brasilenseFP2. A novel approach was applied to identify strain-specific DNA sequences based on a comparison of the genomic sequences within the same species. The draft genome sequences ofA. brasilenseFP2 and Sp245 were aligned, and FP2-specific regions were filtered and checked for other possible matches in public databases. Strain-specific regions were then selected to design and evaluate strain-specific primer pairs. The primer pairs AzoR2.1, AzoR2.2, AzoR5.1, AzoR5.2, and AzoR5.3 were specific for theA. brasilenseFP2 strain. These primer pairs were used to monitor quantitatively the population ofA. brasilensein wheat roots under sterile and nonsterile growth conditions. In addition, coinoculations with other plant growth-promoting bacteria in wheat were performed under nonsterile conditions. The results showed thatA. brasilenseFP2 inoculated into wheat roots is highly competitive and achieves high cell numbers (∼107CFU/g [fresh weight] of root) in the rhizosphere even under nonsterile conditions and when coinoculated with other rhizobacteria, maintaining the population at rather stable levels for at least up to 13 days after inoculation. The strategy used here can be applied to other organisms whose genome sequences are available.

scholarly journals Potential of Algae–Bacteria Synergistic Effects on Vegetable Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Yeeun Kang ◽  
Minjeong Kim ◽  
Changki Shim ◽  
Suyea Bae ◽  
Seonghoe Jang
Keyword(s):  
Soil Fertility ◽  
Plant Pathogens ◽  
Synergistic Effects ◽  
Single Species ◽  
Vegetable Production ◽  
Plant Growth Promoting Bacteria ◽  
Chemical Fertilizers ◽  
Modern Agriculture ◽  
Agricultural Applications ◽  
Plant Growth Promoting

Modern agriculture has become heavily dependent on chemical fertilizers, which have caused environmental pollution and the loss of soil fertility and sustainability. Microalgae and plant growth-promoting bacteria (PGPB) have been identified as alternatives to chemical fertilizers for improving soil fertility. This is because of their biofertilizing properties, through the production of bioactive compounds (e.g., phytohormones, amino acids, and carotenoids) and their ability to inhibit plant pathogens. Although treatment based on a single species of microalgae or bacteria is commonly used in agriculture, there is growing experimental evidence suggesting that a symbiotic relationship between microalgae and bacteria synergistically affects each other’s physiological and metabolomic processes. Moreover, the co-culture/combination treatment of microalgae and bacteria is considered a promising approach in biotechnology for wastewater treatment and efficient biomass production, based on the advantage of the resulting synergistic effects. However, much remains unexplored regarding the microalgal–bacterial interactions for agricultural applications. In this review, we summarize the effects of microalgae and PGPB as biofertilizing agents on vegetable cultivation. Furthermore, we present the potential of the microalgae–PGPB co-culture/combination system for the environmentally compatible production of vegetables with improved quality.

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