scholarly journals Rhizosphere Colonization Determinants by Plant Growth-Promoting Rhizobacteria (PGPR)

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 475
Author(s):  
Gustavo Santoyo ◽  
Carlos Alberto Urtis-Flores ◽  
Pedro Damián Loeza-Lara ◽  
Ma. del Carmen Orozco-Mosqueda ◽  
Bernard R. Glick
Keyword(s):  
Plant Growth ◽  
Antioxidant Activities ◽  
Plant Growth Promoting Rhizobacteria ◽  
Bacterial Strains ◽  
Secretion Systems ◽  
Lytic Enzymes ◽  
Volatile Organic ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Phytopathogenic Microorganisms

The application of plant growth-promoting rhizobacteria (PGPR) in the field has been hampered by a number of gaps in the knowledge of the mechanisms that improve plant growth, health, and production. These gaps include (i) the ability of PGPR to colonize the rhizosphere of plants and (ii) the ability of bacterial strains to thrive under different environmental conditions. In this review, different strategies of PGPR to colonize the rhizosphere of host plants are summarized and the advantages of having highly competitive strains are discussed. Some mechanisms exhibited by PGPR to colonize the rhizosphere include recognition of chemical signals and nutrients from root exudates, antioxidant activities, biofilm production, bacterial motility, as well as efficient evasion and suppression of the plant immune system. Moreover, many PGPR contain secretion systems and produce antimicrobial compounds, such as antibiotics, volatile organic compounds, and lytic enzymes that enable them to restrict the growth of potentially phytopathogenic microorganisms. Finally, the ability of PGPR to compete and successfully colonize the rhizosphere should be considered in the development and application of bioinoculants.

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.

scholarly journals Volatile Organic Compounds of the Plant Growth-Promoting Rhizobacteria JZ-GX1 Enhanced the Tolerance of Robinia pseudoacacia to Salt Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Pu-Sheng Li ◽  
Wei-Liang Kong ◽  
Xiao-Qin Wu ◽  
Yu Zhang
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Plant Growth ◽  
Lateral Root ◽  
Robinia Pseudoacacia ◽  
Plant Growth Promoting Rhizobacteria ◽  
Stress Conditions ◽  
Volatile Organic ◽  
Plant Growth Promoting ◽  
Growth Promoting

Salt stress is one of the major abiotic stresses that affects plant growth and development. The use of plant growth-promoting rhizobacteria to mitigcate salt stress damage in plants is an important way to promote crop growth under salt stress conditions. Rahnella aquatilis JZ-GX1 is a plant growth-promoting rhizobacterial strain, but it is not clear whether it can improve the salt tolerance of plants, and in particular, the role of volatile substances in plant salt tolerance is unknown. We investigated the effects of volatile organic compounds (VOCs) from JZ-GX1 on the growth performance, osmotic substances, ionic balance and antioxidant enzyme activities of acacia seedlings treated with 0 and 100mm NaCl and explored the VOCs associated with the JZ-GX1 strain. The results showed that compared to untreated seedlings, seedlings exposed to plant growth-promoting rhizobacterium JZ-GX1 via direct contact with plant roots under salt stress conditions exhibited increases in fresh weight, lateral root number and primary root length equal to approximately 155.1, 95.4, and 71.3%, respectively. Robinia pseudoacacia seedlings exposed to VOCs of the JZ-GX1 strain showed increases in biomass, soil and plant analyser development values and lateral root numbers equal to 132.1, 101.6, and 166.7%, respectively. Additionally, decreases in malondialdehyde, superoxide anion (O2−) and hydrogen peroxide (H2O2) contents and increases in proline contents and superoxide dismutase, peroxidase and glutathione reductase activities were observed in acacia leaves. Importantly, the sodium-potassium ratios in the roots, stems, and leaves of acacia exposed to VOCs of the JZ-GX1 strain were significantly lower than those in the control samples, and this change in ion homeostasis was consistent with the upregulated expression of the (Na+, K+)/H+ reverse cotransporter RpNHX1 in plant roots. Through GC-MS and creatine chromatography, we also found that 2,3-butanediol in the volatile gases of the JZ-GX1 strain was one of the important signaling substances for improving the salt tolerance of plants. The results showed that R. aquatilis JZ-GX1 can promote the growth and yield of R. pseudoacacia under normal and salt stress conditions. JZ-GX1 VOCs have good potential as protectants for improving the salt tolerance of plants, opening a window of opportunity for their application in salinized soils.

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.

scholarly journals Plant Growth-Promoting Rhizobacteria Modulate the Concentration of Bioactive Compounds in Tomato Fruits

Separations ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 223
Author(s):  
Clara de la Osa ◽  
Miguel Ángel Rodríguez-Carvajal ◽  
Jacinto Gandullo ◽  
Clara Aranda ◽  
Manuel Megías ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Plant Growth ◽  
Agricultural Soils ◽  
Antioxidant Activities ◽  
Plant Growth Promoting Rhizobacteria ◽  
Rice Paddy ◽  
Bioactive Molecules ◽  
Cultivated Rice ◽  
Plant Growth Promoting ◽  
Growth Promoting

Background: The application of microorganisms as bioestimulants in order to increase the yield and/or quality of agricultural products is becoming a widely used practice in many countries. In this work, five plant growth-promoting rhizobacteria (PGPR), isolated from cultivated rice paddy soils, were selected for their plant growth-promoting capacities (e.g., auxin synthesis, chitinase activity, phosphate solubilisation and siderophores production). Two different tomato cultivars were inoculated, Tres Cantos and cherry. Plants were grown under greenhouse conditions and different phenotypic characteristics were analysed at the time of harvesting. Results: Tres Cantos plants inoculated with PGPR produced less biomass but larger fruits. However, the photosynthetic rate was barely affected. Several antioxidant activities were upregulated in these plants, and no oxidative damage in terms of lipid peroxidation was observed. Finally, ripe fruits accumulated less sugar but, interestingly, more lycopene. By contrast, inoculation of cherry plants with PGPR had no effect on biomass, although photosynthesis was slightly affected, and the productivity was similar to the control plants. In addition, antioxidant activities were downregulated and a higher lipid peroxidation was detected. However, neither sugar nor lycopene accumulation was altered. Conclusion: These results support the use of microorganisms isolated from agricultural soils as interesting tools to manipulate the level of important bioactive molecules in plants. However, this effect seems to be very specific, even at the variety level, and deeper analyses are necessary to assess their use for specific applications.

Sign in / Sign up

Export Citation Format

Share Document