Long-term survival of the plant-growth-promoting bacteria Azospirillum brasilense and Pseudomonas fluorescens in dry alginate inoculant

1999 ◽  
Vol 51 (2) ◽  
pp. 262-266 ◽  
Author(s):  
Y. Bashan ◽  
L. E. Gonzalez
Keyword(s):  
Plant Growth ◽  
Pseudomonas Fluorescens ◽  
Azospirillum Brasilense ◽  
Plant Growth Promoting Bacteria ◽  
Term Survival ◽  
Long Term Survival ◽  
Plant Growth Promoting ◽  
Growth Promoting

Involvement ofgacSandrpoSin enhancement of the plant growth-promoting capabilities ofEnterobacter cloacaeCAL2 and UW4

2001 ◽  
Vol 47 (8) ◽  
pp. 698-705 ◽  
Author(s):  
Saleema S Saleh ◽  
Bernard R Glick
Keyword(s):  
Plant Growth ◽  
Pseudomonas Fluorescens ◽  
Indoleacetic Acid ◽  
Acc Deaminase ◽  
Enterobacter Cloacae ◽  
Lag Phase ◽  
Plant Growth Promoting Bacteria ◽  
Multicopy Plasmid ◽  
Plant Growth Promoting ◽  
Growth Promoting

The plant growth-promoting bacteria Enterobacter cloacae CAL2 and UW4 were genetically transformed with a multicopy plasmid containing an rpoS or gacS gene from Pseudomonas fluorescens. The transformed strains were compared with the nontransformed strains for growth, indoleacetic acid (IAA) production, antibiotic production, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, siderophore production, cell morphology, and the ability to promote canola root elongation. All transformed strains had a longer lag phase, were slower in reaching stationary phase, and attained a higher cell density than the nontransformed strains. Transformation resulted in cells that were significantly shorter than the nontransformed cells. The transformed strains also produced significantly more IAA than the nontransformed strains. Introduction of rpoS or gacS from Pseudomonas fluorescens was associated with a reduction in the production of both antibiotics, 2,4-diacetylphloroglucinol and mono-acetylphloroglucinol, produced by Enterobacter cloacae CAL2. With Enterobacter cloacae CAL2, plasmid-borne rpoS, but not gacS, increased the level of ACC deaminase activity, while introduction of rpoS in Enterobacter cloacae UW4 caused a decrease in ACC deaminase activity. Neither gacS nor rpoS significantly affected the level of siderophores synthesized by either bacterial strain. Overproduction of either GacA or RpoS in Enterobacter cloacae CAL2 resulted in a significant increase in the root lengths of canola seedlings when seeds were treated with the bacteria, and overproduction of RpoS caused an increase in canola shoot as well as root lengths.Key words: plant growth-promoting bacteria, canola, ethylene, ACC deaminase, GacS, RpoS, indoleacetic acid, siderophores, antibiotics.

Colonization and persistence of a plant growth-promoting bacterium Pseudomonas fluorescens strain CS85, on roots of cotton seedlings

2004 ◽  
Vol 50 (7) ◽  
pp. 475-481 ◽  
Author(s):  
Chunxia Wang ◽  
Daoben Wang ◽  
Qi Zhou
Keyword(s):  
Plant Growth ◽  
Pseudomonas Fluorescens ◽  
Growth Promotion ◽  
Lateral Roots ◽  
Marker Genes ◽  
Original Strain ◽  
Plant Growth Promoting Bacteria ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Root Surfaces

Pseudomonas fluorescens CS85, which was previously isolated from the rhizosphere of cotton seedlings, acts as both a plant growth-promoting bacterium and a biocontrol agent against cotton pathogens, including Rhizoctonia solani, Colletotrichum gossypii, Fusarium oxysporum f sp. vasinfectum, and Verticillium dahliae. Strain CS85 was labeled separately with luxAB and gusA. The labeled strains were stably maintained and had high levels of expression of the marker genes, luxAB and gusA, after successive transfers on nonselective medium, long-term preservation, and after recovery from soil. The labeled strains displayed similar biocontrol characteristics (e.g., antibiosis, effects of growth -promotion and disease -control) to the original strain. The labeled strains colonized all surfaces of the young plant root zones, such as roots hairs and lateral roots, although the distribution of the labeled strains on the root surfaces was not uniform. Moreover, the population densities of the labeled strains on the root surface were stably maintained at high levels during the first 2 weeks of plant growth in the native soil, so that about 107–108 CFU/g root were detected, then decreased gradually. Nevertheless, approximately 106 CFU/g root of the labeled strains were observed on the root surfaces 35 d after planting.Key words: plant growth-promoting bacteria, luxAB, gusA, root colonization.

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 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.

Improved establishment and development of three cactus species inoculated withAzospirillum brasilensetransplanted into disturbed urban desert soil

1999 ◽  
Vol 45 (6) ◽  
pp. 441-451 ◽  
Author(s):  
Yoav Bashan ◽  
Adriana Rojas ◽  
M Esther Puente
Keyword(s):  
Soil Erosion ◽  
Plant Growth ◽  
Azospirillum Brasilense ◽  
Soil Reclamation ◽  
High Survival ◽  
Plant Growth Promoting Bacteria ◽  
Disturbed Areas ◽  
Small Roots ◽  
Plant Growth Promoting ◽  
Growth Promoting

Survival and development of cactus transplants in urban, disturbed areas of the desert near La Paz, Baja California Sur, Mexico, was monitored. Young plants of three species of pachycereid cacti (Pachycereus pringlei, Stenocereus thurberi, and Lophocereus schottii) inoculated with the plant growth promoting bacterium Azospirillum brasilense in an eroded area (a dirt road) had a high survival rate and developed more rapidly compared with uninoculated control plants during a 3.5-year period after transplantation. Soil erosion in the inoculated experimental area diminished. Small, but significant soil accumulated in association with the growth of cactus roots into the wind-deposited dust. One demonstrated mechanism for stabilizing dust was by the upward growth of small roots during the rainy season into the deposited dust. Azospirillum brasilense survived well in the rhizospheres of these cacti for 2 years, but not in root-free soil. This study demonstrated the feasibility of using bacterial inoculation of cacti to enhance their establishment in disturbed areas, with the potential to stabilize soil.Key words: Azospirillum, beneficial bacteria, cactus, plant inoculation, plant growth promoting bacteria, PGPR, soil erosion, soil reclamation.

The effect of native and ACC deaminase-containing Azospirillum brasilense Cd1843 on the rooting of carnation cuttings

2005 ◽  
Vol 51 (6) ◽  
pp. 511-514 ◽  
Author(s):  
Qiaosi Li ◽  
Saleema Saleh-Lakha ◽  
Bernard R Glick
Keyword(s):  
Plant Growth ◽  
Azospirillum Brasilense ◽  
Indoleacetic Acid ◽  
Acc Deaminase ◽  
Plant Growth Promoting Bacteria ◽  
Indolebutyric Acid ◽  
Proposed Model ◽  
Plant Growth Promoting ◽  
Growth Promoting

Carnation cuttings treated with non-transformed and 1-aminocyclopropane (ACC) deaminase-containing Azospirillum brasilense Cd1843 produced significantly more roots than untreated controls and fewer roots than cuttings treated with 0.1% indolebutyric acid (IBA). The roots produced by cuttings treated with ACC deaminase-containing Azospirillum brasilense Cd1843 were the longest roots resulting from any of the treatments, followed by non-transformed Azospirillum brasilense Cd1843, 0.1% IBA, and treatment with water. The results are interpreted in terms of a previously proposed model of bacterial promotion of plant growth by ACC deaminase and indoleacetic acid, and may have implications for the use of plant growth-promoting bacteria in the flower industry.Key words: ACC deaminase, carnation, cuttings, rooting, Azospirillum brasilense.

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