Plant-Growth-Promoting Rhizobacteria: Potential Candidates for Gibberellins Production and Crop Growth Promotion

2013 ◽  
pp. 1-19 ◽  
Author(s):  
Sang-Mo Kang ◽  
Muhammad Waqas ◽  
Abdul Latif Khan ◽  
In-Jung Lee
Keyword(s):  
Plant Growth ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Crop Growth ◽  
Plant Growth Promoting ◽  
Growth Promoting

Rhizobium leguminosarum as a plant growth-promoting rhizobacterium: direct growth promotion of canola and lettuce

1996 ◽  
Vol 42 (3) ◽  
pp. 279-283 ◽  
Author(s):  
T. C. Noel ◽  
C. Sheng ◽  
C. K. Yost ◽  
R. P. Pharis ◽  
M. F. Hynes
Keyword(s):  
Acetic Acid ◽  
Plant Growth ◽  
Rhizobium Leguminosarum ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Growth Promoting ◽  
Direct Growth ◽  
Early Seedling ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid

Early seedling root growth of the nonlegumes canola (Brassica campestris cv. Tobin, Brassica napus cv. Westar) and lettuce (Lactuca saliva cv. Grand Rapids) was significantly promoted by inoculation of seeds with certain strains of Rhizobium leguminosarum, including nitrogen- and nonnitrogen-fixing derivatives under gnotobiotic conditions. The growfh-promotive effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. Auxotrophic Rhizobium mutants requiring tryptophan or adenosine (precursors for indole-3-acetic acid and cytokinin synthesis, respectively) did not promote growth to the extent of the parent strain. The findings of this study demonstrate a new facet of the Rhizobium–plant relationship and that Rhizobium leguminosarum can be considered a plant growth-promoting rhizobacterium (PGPR).Key words: Rhizobium, plant growth-promoting rhizobacteria, PGPR, indole-3-acetic acid, cytokinin, roots, auxotrophic mutants.

Colonization and growth promotion of outplanted spruce seedlings pre-inoculated with plant growth-promoting rhizobacteria in the greenhouse

2000 ◽  
Vol 30 (6) ◽  
pp. 845-854 ◽  
Author(s):  
Masahiro Shishido ◽  
Christopher P Chanway
Keyword(s):  
Plant Growth ◽  
Seedling Growth ◽  
Picea Glauca ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Population Declines ◽  
Growth Responses ◽  
Relative Growth Rates ◽  
Plant Growth Promoting ◽  
Growth Promoting

Seeds of two hybrid spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) ecotypes were inoculated with one of six plant growth-promoting rhizobacteria (PGPR) strains previously shown to be able to stimulate spruce growth in controlled environments. The resulting seedlings were grown in the greenhouse for 17 weeks before outplanting at four reforestation sites. Inoculation with five of the six strains caused significant seedling growth promotion in the greenhouse, which necessitated analysis of relative growth rates (RGR) to evaluate seedling performance in the field. Four months after outplanting, most strains enhanced spruce shoot or root RGRs in the field, but seedling growth responses were strain specific. For example, Pseudomonas strain Ss2-RN significantly increased both shoot and root RGRs by 10-234% at all sites, but increases of 28-70% were most common. In contrast, Bacillus strain S20-R was ineffective at all outplanting sites. In addition, seedlings inoculated with four of the six strains had significantly less shoot injury than control seedlings at all sites. Evaluation of root colonization by PGPR indicated that bacterial population declines were not related to spruce growth response variability in the field. Our results indicate that once plant growth promotion is induced in the greenhouse, seedling RGR can increase by more than 100% during the first growing season in the field. However RGR increases of 21-47% were more common and may be more representative of the magnitude of biomass increases that can result from PGPR inoculation.

scholarly journals Characterization of Selected Plant Growth-Promoting Rhizobacteria and Their Non-Host Growth Promotion Effects

2021 ◽  
Author(s):  
Di Fan ◽  
Donald L. Smith
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Content Type ◽  
Host Growth ◽  
Plant Growth Promoting ◽  
Growth Promoting

There are pressing needs to reduce the use of agrochemicals, and PGPR are receiving increasing interest in plant growth promotion and disease protection. This study follows up our previous report that the four newly isolated rhizobacteria promote the growth of Arabidopsis thaliana .

scholarly journals Impact of Plant Growth Promoting Rhizobacteria in Sustainable Agriculture: An Important Natural Resource for Crop Improvement

2019 ◽  
Vol 5 (03) ◽  
pp. 210-214
Author(s):  
Debnirmalya Gangopadhyay ◽  
Ashmita Ghosh
Keyword(s):  
Plant Growth ◽  
Sustainable Agriculture ◽  
Crop Yields ◽  
Growth Promotion ◽  
Crop Improvement ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Increasing Demand ◽  
Environmentally Sound

It is usually admitted that the chemical fertilizers and pesticides used in modern agriculture create a real environmental and public health problems. The increasing demand for production with a significant reduction of synthetic fertilizers and pesticides use is a big challenge nowadays. The use of plant growth promoting rhizobacteria or PGPR has been proven to be an environmentally sound way of increasing crop yields by facilitating plant growth through either a direct or indirect mechanism. They play an important role to increase in soil fertility, plant growth promotion and suppression of phytopathogens for development of ecofriendly sustainable agriculture. In view of the latest advances in PGPR biotechnology, this paper proposes to do the review on PGPR in rhizosphere and describes the different mechanisms used by PGPR to promote the plants growth and health. In prospect to a healthy and sustainable agriculture, the PGPR approach revealed as one of the best ecofriendly alternatives.

scholarly journals A Framework for the Selection of Plant Growth-Promoting Rhizobacteria Based on Bacterial Competence Mechanisms

2020 ◽  
Vol 86 (14) ◽  
Author(s):  
Carol V. Amaya-Gómez ◽  
Mario Porcel ◽  
Leyanis Mesa-Garriga ◽  
Martha I. Gómez-Álvarez
Keyword(s):  
Hydrogen Peroxide ◽  
Plant Growth ◽  
Decision Analysis ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Plant Growth Promoting Rhizobacteria ◽  
Screening Strategy ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Selection Of

ABSTRACT The use of plant growth-promoting rhizobacteria (PGPR) is increasingly meaningful for the development of more environmentally friendly agricultural practices. However, often the PGPR strains selected in the laboratory fail to confer the expected beneficial effects when evaluated in plant experiments. Insufficient rhizosphere colonization is pointed out as one of the causes. With the aim of minimizing this inconsistency, we propose that besides studying plant growth promotion traits (PGP), the screening strategy should include evaluation of the microbial phenotypes required for colonization and persistence. As a model, we carried out this strategy in three Rhizobium sp. strains that showed phosphorus solubilization ability and production of siderophores. All strains displayed colonization phenotypes like surface spreading, resistance to hydrogen peroxide, and formed biofilms. Regarding their ability to persist, biofilm formation was observed to be influenced by pH and the phosphorus nutrient provided in the growth media. Differences in the competence of the strains to use several carbon substrates were also detected. As part of our framework, we compared the phenotypic characteristics of the strains in a quantitative manner. The data analysis was integrated using a multicriteria decision analysis (MCDA). All our results were scored, weighted, and grouped as relevant for PGP, colonization, or persistence. MCDA demonstrated that, when the phenotypes related to PGP and colonization are weighted over those for persistence, strain B02 performs better than the other two Rhizobium sp. strains. The use of our framework could assist the selection of more competent strains to be tested in greenhouse and field trials. IMPORTANCE Numerous plant growth-promoting rhizobacteria (PGPR) have been inoculated into the soil with the aim of improving the supply of nutrients to crop plants and decreasing the requirement of chemical fertilizers. However, sometimes these microbes fail to competitively colonize the plant roots and rhizosphere. Hence, the plant growth promotion effect is not observed. Here, we describe a new screening strategy aiming at the selection of more competent PGPR. We evaluated bacterial phenotypes related to plant growth promotion, colonization, and persistence. Our results demonstrated that despite the fact that our Rhizobium sp. strains successfully solubilized phosphorus and produced siderophores, their abilities to spread over surfaces, resist hydrogen peroxide, and form biofilms varied. Additionally, a multicriteria decision analysis was used to analyze the data that originated from bacterial physiological characterizations. This analysis allowed us to innovatively evaluate each strain as a whole and compare the performances of the strains under hypothetical scenarios of bacterial-trait requirements.

The growth-promoting effects of a bacterial endophyte on lodgepole pine are partially inhibited by the presence of other rhizobacteria

1998 ◽  
Vol 44 (10) ◽  
pp. 980-988 ◽  
Author(s):  
Elizabeth Bent ◽  
Christopher P Chanway
Keyword(s):  
Plant Growth ◽  
Growth Promotion ◽  
Lodgepole Pine ◽  
Primary Root ◽  
Biomass Accumulation ◽  
Plant Growth Promoting Rhizobacteria ◽  
Shoot Biomass ◽  
Bacillus Polymyxa ◽  
Plant Growth Promoting ◽  
Growth Promoting

To test the hypothesis that rhizobacteria naturally present in soils may interfere with the extent of root colonization and plant growth promotion by plant growth-promoting rhizobacteria (PGPR), we studied two lodgepole pine PGPR (Bacillus polymyxa strains L6 and Pw-2) when inoculated singly and when coinoculated with a non-PGPR competitor (Curtobacterium flaccumfaciens PF322). Bacillus polymyxa Pw-2 and Curtobacterium flaccumfaciens PF322 were consistently found as endophytes, while Bacillus polymyxa L6 was never found within the root interior. Strains Pw-2 and L6 differed in the rate and type of growth promotion. Strain Pw-2 increased root growth (branching and elongation) and shoot biomass accumulation 6 and 9 weeks, respectively, after inoculation, while strain L6 increased primary root elongation and root biomass accumulation after 12 weeks. Seedlings coinoculated with Pw-2 and PF322 had decreased shoot biomass and primary root lengths when compared with seedlings inoculated only with Pw-2. This effect was not linked to a decrease in the population size of Pw-2 in the rhizosphere or in the root interior of coinoculated treatments. In contrast, strain L6-mediated growth promotion was not impaired by coinoculation with PF322. Strain L6 did interfere to some degree with the growth-promoting capability of strain Pw-2. These results indicate that endophytic PGPR may be less adapted to microbial competition than external root-colonizing PGPR, and that the efficacy of endophytic PGPR may be reduced by the presence of other bacteria on external or internal root tissues.Key words: PGPR, endophytes, colonization, coinoculation, competition.

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