scholarly journals Biodegradation of naphthalene mediated by the plant growth promoting rhizobacteria

2021 ◽  
Author(s):  
Salme Timmusk ◽  
Tiiu Teder ◽  
Lawrence Behers
Keyword(s):  
Carbon Sources ◽  
Paenibacillus Polymyxa ◽  
Extracellular Polysaccharide ◽  
Plant Growth Promoting Rhizobacteria ◽  
Minimal Salt Medium ◽  
Bacterial Strains ◽  
Surface Tension Reduction ◽  
Polycyclic Aromatic ◽  
Luminescence Inhibition ◽  
Plant Growth Promoting

We compared the ability of two bacterial strains, Paenibacillus polymyxa A26 and P. polymyxa A26Sfp, for biodegradation of naphthalene (NAP). The studies were performed under simulated laboratory conditions, in liquid medium and soil with different carbon sources, pH and salt contents. Changes in the luminescence inhibition of Aliivibrio fischeri, as an indicator of the baseline toxicity, were observed in degradation mixtures during 7 days of incubation. While both strains expressed the best growth and NAP degradation ability in the minimal salt medium containing sucrose and 5% NaCl at pH 8, the mutant strain remained effective even under extreme conditions. A26Sfp was found to be an efficient and potentially industrially important polycyclic aromatic hydrocarbon degradation strain. Its extracellular polysaccharide production is 30% and glucan production twice that of the wild type A 26. The surface tension reduction ability was ascertained as 25 to 30% increased emulsification ability.

scholarly journals Paenibacillus polymyxa A26 and Its Surfactant-Deficient Mutant Degradation of Polycyclic Aromatic Hydrocarbons

Stresses ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 266-276
Author(s):  
Salme Timmusk ◽  
Tiiu Teder ◽  
Lawrence Behers
Keyword(s):  
Carbon Sources ◽  
Paenibacillus Polymyxa ◽  
Extracellular Polysaccharide ◽  
Minimal Salt Medium ◽  
Bacterial Strains ◽  
Surface Tension Reduction ◽  
Polycyclic Aromatic ◽  
Luminescence Inhibition ◽  
Aliivibrio Fischeri ◽  
Degradation Ability

We compared the ability of two bacterial strains, Paenibacillus polymyxa A26 and P. polymyxa A26Sfp, for biodegradation of naphthalene (NAP). The studies were performed under simulated laboratory conditions, in liquid medium and soil with different carbon sources, pH and salt contents. Changes in the luminescence inhibition of Aliivibrio fischeri, as an indicator of the baseline toxicity, were observed in degradation mixtures during 7 days of incubation. While both strains expressed the best growth and NAP degradation ability in the minimal salt medium containing sucrose and 5% NaCl at pH 7 and 8, the mutant strain remained effective even under extreme conditions. A26Sfp was found to be an efficient and potentially industrially important polycyclic aromatic hydrocarbon degradation strain. Its extracellular polysaccharide production is 30%, and glucan production is twice that of the wild type A 26. The surface tension reduction ability was ascertained as 25–30% increased emulsification ability.

scholarly journals PGPR Characteristics of Rhizospheric Bacteria to Understand the Mechanisms of Faba Bean Growth

Proceedings ◽  
2021 ◽  
Vol 66 (1) ◽  
pp. 27
Author(s):  
Rim Tinhinen Maougal ◽  
Maya Kechid ◽  
Chaima Ladjabi ◽  
Abdelhamid Djekoun
Keyword(s):  
Plant Growth ◽  
Faba Bean ◽  
Biochemical Characterization ◽  
Plant Growth Promoting Rhizobacteria ◽  
Bacterial Strains ◽  
Rhizospheric Bacteria ◽  
Plant Growth Promoting ◽  
Pgpr Traits ◽  
Taxonomic Groups ◽  
High Degree

Rhizobacteria play an important role in maintaining soil balance. Among these bacteria, there are those taht have shown their ability to promote the growth of plants, known as Plant Growth Promoting Rhizobacteria (PGPR). In our work, we are interested in characterizing 110 bacterial strains isolated in the field in the region of Ben Badis (Constantine Algeria) from 5 varieties of faba bean. Phenotypic and biochemical characterization showed that most of the isolates are cream-colored, slightly raised, flat and opaque, Gram−, catalase+ and oxidase−, and Bacillus form. PCA analysis allowed us to select 40 isolates with a high degree of variability to continue our work. The results obtained have directed us towards different taxonomic groups (rhizobium, Pseudomonas, Bacillus etc.). The evaluation of the PGPR potential of bacteria (phytostimulation, biofertilization and biocontrol), showed that 100% of bacteria are able to produce auxin at different concentrations, with the highest concentration (177.77 µg/mL) for the isolate 6, and that more than 50% of isolates are capable of producing nitrogen, ammonia and phytate mineralization. These PGPR traits have a direct effect on plant growth of five varieties of the faba bean and can be used to select the best performing bacteria for inoculation tests.

scholarly journals Selection of Saccharum spp. rhizobacteria with growth-promoting properties using PCA analysis

2020 ◽  
pp. 1186-1194
Author(s):  
Roberta Mendes dos Santos ◽  
Everlon Cid Rigobelo
Keyword(s):  
Plant Growth ◽  
Principal Component ◽  
Plant Growth Promoting Rhizobacteria ◽  
Cellulolytic Activity ◽  
Bacterial Strains ◽  
Saccharum Spp ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Enterobacter Asburiae ◽  
Selection Of

The search for plant growth-promoting rhizobacteria is an ongoing need for the development of new bioinoculants for use in various crops, including sugarcane. Bacterial strains with various plant growth-promoting properties can contribute to sustainable agricultural production. The present study aimed to isolate, characterize and select sugarcane rhizobacteria from six different varieties through principal components analysis. This study selected 167 bacterial strains with the ability to fix nitrogen, produce indolacetic acid, exhibit cellulolytic activity, and solubilize phosphate and potassium were isolated. Of these 167 bacterial strains, seven were selected by principal component analysis and identified as belonging to the genera Staphylococcus, Enterobacter, Bacillus and Achromobacter. Bacillus thuringiensis IP21 presented higher potential for nitrogen fixation and CaPO4 and AlPO4 solubilization and a lower potential for K solubilization in sugarcane. Enterobacter asburiae IP24 was efficient in indolacetic acid production and CaPO4 and FePO4 solubilization and inefficient for Araxá apatite solubilization.

A review of issues related to measuring colonization of plant roots by bacteria

1992 ◽  
Vol 38 (12) ◽  
pp. 1219-1232 ◽  
Author(s):  
Joseph W. Kloepper ◽  
Chantal J. Beauchamp
Keyword(s):  
Dna Sequences ◽  
Root Colonization ◽  
Dry Weight ◽  
Plant Growth Promoting Rhizobacteria ◽  
Bacterial Strains ◽  
Advantages And Disadvantages ◽  
Plant Growth Promoting ◽  
Statistical Issues ◽  
Definition Of ◽  
Rhizosphere Community

Root colonization by introduced bacteria is an important step in the interaction of beneficial bacteria with the host plant. Investigators attempting to measure root colonization by bacteria must face several issues. A clear concept or definition of root colonization should be stated in each research summary, as several different definitions have been proposed. We consider true root colonists to be those bacteria that colonize roots in competitive conditions, i.e., natural field soils. Different methods of processing root samples are required if one is measuring external root colonization alone, internal colonization alone, or both. Given that most beneficial bacterial strains currently under investigation as root colonists are members of taxa naturally found in soils, a marking system is required to differentiate the introduced strain from members of the indigenous rhizosphere community. Spontaneous antibiotic resistance, immunological approaches, and foreign DNA sequences are among the marking systems that have been used and each has some possible advantages and disadvantages. More research is needed in the development and comparison of marking systems. The design of experiments to measure root colonization should take into account several statistical issues. One must decide what constitutes the sample unit for each replication of a given treatment, e.g., whole root systems or root segments. Consideration should also be given to how best to express the estimated population of root colonists (e.g., cfu/g fresh or dry weight root, cfu/cm root, or cfu/surface area root). Statistical analysis by standard analysis of variance tests should be used whenever possible to separate treatment means of colonization levels; however, one must determine that the underlying assumptions of these tests are correct for each experiment. Finally, in quantification of populations on roots, one will almost certainly encounter replications with no bacteria, i.e., zeros. There are several options for how to calculate treatment means when one or more replications is a zero, and the implications of these options are discussed. Key words: bioluminescence, genetic markers, plant growth-promoting rhizobacteria, rhizosphere bacteria, root, colonization.

scholarly journals Selection of Mercury-Resistant PGPR Strains Using the BMRSI for Bioremediation Purposes

2021 ◽  
Vol 18 (18) ◽  
pp. 9867
Author(s):  
Daniel González ◽  
Marina Robas ◽  
Agustín Probanza ◽  
Pedro A. Jiménez
Keyword(s):  
Contaminated Soils ◽  
Plant Growth Promoting Rhizobacteria ◽  
Mining District ◽  
Bacterial Strains ◽  
Ciudad Real ◽  
Agriculture Industry ◽  
Suitability Index ◽  
Plant Growth Promoting ◽  
Potential Use

Heavy metal pollution of soil, particularly by mercury (Hg), is a problem that can seriously affect the environment and human health. For this reason, it is necessary to take steps to remediate these environments, prevent potential adverse effects, and restore these areas for subsequent use in agriculture, industry, ranching, and forestry. The present study has selected 40 bacterial strains from rhizosphere and bulk soil that grow naturally in high Hg-contaminated soils from the Almadén mining district in Ciudad Real, Spain. With the objective of evaluating the potential use of these strains in phyto-rhizoremediation, an evaluation and statistical analysis of their PGPR (Plant-Growth-Promoting Rhizobacteria) activity at different levels of Hg was carried out as the first condition of selection for their potential use in bioremediation. In addition, a Hg MBC (Maximum Bactericidal Concentration) was performed with the aim of selecting the strains with high Hg tolerance. Finally, strains with potential biotechnological use have been proposed according to the Bio-Mercury Remediation Suitability Index (BMRSI) criteria, which consider indole-3-acetic acid (IAA) production, acid 1- aminocyclopropane-1-carboxylic deaminase (ACCd) activity, phosphates solubilization, and siderophore production measured in the presence of Hg, as well as its MBC to Hg. The strains selected for further in vivo and in situ processes must reach at least an MBC (Hg) > 100 μg/mL and BMRSI ≥ 6.5.

scholarly journals A Critical Review on Plant Growth-Promoting Rhizobacteria (PGPR) as a Drought Stress Management Tool

2021 ◽  
pp. 44-66
Author(s):  
Shamal S. Kumar ◽  
Ananta G. Mahale ◽  
Md. Mifta Faizullah ◽  
J. Radha Krishna ◽  
Tharun K. Channa
Keyword(s):  
Drought Stress ◽  
Plant Growth ◽  
Plant Root ◽  
Acc Deaminase ◽  
Plant Growth Promoting Rhizobacteria ◽  
Management Tool ◽  
Abiotic Factor ◽  
Bacterial Strains ◽  
Plant Growth Promoting ◽  
Growth Promoting

Water scarcity is known as a major stumbling block towards crop development and its output all over the world. Certain free-living bacterial strains have been found near the plant root zones which have shown to improve resistance of plants towards water stress. Despite availability of basic nutrients, drought an abiotic factor substantially inhibits growth, development and yield of crops by causing an increase in ethylene levels. It is a good idea to incorporate the use of a management tool which is the utilization of plant growth-promoting rhizobacteria to help several crops manage drought conditions. Drought stress in crops can be alleviated by reducing ethylene synthesis, exopolysaccharide, osmoregulation, Indole-3-acetic acid and aggregation with the ACC deaminase-containing plant growth-promoting rhizobacteria. Inoculating pathogens like root rot (Macrophomina phaseolina) affected plant with Pseudomonas fluorescens strain TDK1 with ACC deaminase function improves drought stress. Using plant growth-promoting rhizobacteria to mitigate the negative imbibes of drought in most crops is a good idea. Several studies have been carried out on plant growth-promoting rhizobacteria, as its inoculation not only manages drought related conditions but increases root hair growth and lateral root, which assist in increased water and nutrient uptake. It limits ethylene supply, alternatively increases plant root growth by hydrolyzing 1-aminocyclopropane-1-carboxylic acid (ACC). This review will give us a perspective on the importance of plant growth-promoting rhizobacteria, as it is one of the efficient tools that helps manage drought stress on several crops.

scholarly journals Microbial IAA: Spectral Analysis and Application to Modulate Growth of Triticum aestivum

2018 ◽  
Vol 9 (2) ◽  
pp. 53-63
Author(s):  
Ammara Abid ◽  
Ambreen Ahmed
Keyword(s):  
Triticum Aestivum ◽  
Spectral Analysis ◽  
Plant Growth ◽  
Plant Growth Promoting Rhizobacteria ◽  
Structural Similarity ◽  
Bacterial Strains ◽  
Plant Microbe Interaction ◽  
Plant Growth Promoting ◽  
Microbial Strains ◽  
Growth Promoting

Plant growth promoting rhizobacteria (PGPR) play an essential part in transformation, solubilization, and mobilization of nutrients procured from the soil. Plant-microbe interaction can be termed as an eco-friendly approach which not only improves plant growth but helps in sustaining the soil and prevents environmental degradation from agrochemicals. PGPR improve plant growth through various mechanisms. One of the mechanisms involved is phytohormone production by the bacterial strains. In the current study, spectral analysis of thirteen already isolated and identified auxin-producing microbial strains (AAL1, AB8, A7B, A5C, A3E, A11E, AL2, A9G, A12G, A13G, AM10, P4, and S6) was carried out. Fourier transform infrared spectroscopy (FTIR) of the bacterial IAA exhibited close structural similarity between bacterial IAA and standard IAA. The growth-enhancing capability of strains was verified through the application of these strains on Triticum aestivum seedlings and enhancement of growth was statistically analyzed which indicated remarkable improvement in growth and metabolism both under laboratory and field conditions. Several bacterial isolates also proved to be very effective in improving biochemical parameters of plants. The current study suggested that the application of IAA-producing PGPR as biofertilizer is effective in enhancing plant growth as well as plant yield.

Sign in / Sign up

Export Citation Format

Share Document