scholarly journals Indole-3-Acetic Acid Biosynthesis Is Deficient in Gluconacetobacter diazotrophicus Strains with Mutations in Cytochrome c Biogenesis Genes

2004 ◽  
Vol 186 (16) ◽  
pp. 5384-5391 ◽  
Author(s):  
Sunhee Lee ◽  
M. Flores-Encarnación ◽  
M. Contreras-Zentella ◽  
L. Garcia-Flores ◽  
J. E. Escamilla ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Acetic Acid ◽  
Gene Products ◽  
Gluconacetobacter Diazotrophicus ◽  
Beneficial Effects ◽  
Cytochrome C Biogenesis ◽  
Plant Growth Promoting ◽  
The Individual ◽  
Mutant Phenotypes ◽  
Indole 3 Acetic Acid

ABSTRACT Gluconacetobacter diazotrophicus is an endophyte of sugarcane frequently found in plants grown in agricultural areas where nitrogen fertilizer input is low. Recent results from this laboratory, using mutant strains of G. diazotrophicus unable to fix nitrogen, suggested that there are two beneficial effects of G. diazotrophicus on sugarcane growth: one dependent and one not dependent on nitrogen fixation. A plant growth-promoting substance, such as indole-3-acetic acid (IAA), known to be produced by G. diazotrophicus, could be a nitrogen fixation-independent factor. One strain, MAd10, isolated by screening a library of Tn5 mutants, released only ∼6% of the amount of IAA excreted by the parent strain in liquid culture. The mutation causing the IAA− phenotype was not linked to Tn5. A pLAFR3 cosmid clone that complemented the IAA deficiency was isolated. Sequence analysis of a complementing subclone indicated the presence of genes involved in cytochrome c biogenesis (ccm, for cytochrome c maturation). The G. diazotrophicus ccm operon was sequenced; the individual ccm gene products were 37 to 52% identical to ccm gene products of Escherichia coli and equivalent cyc genes of Bradyrhizobium japonicum. Although several ccm mutant phenotypes have been described in the literature, there are no reports of ccm gene products being involved in IAA production. Spectral analysis, heme-associated peroxidase activities, and respiratory activities of the cell membranes revealed that the ccm genes of G. diazotrophicus are involved in cytochrome c biogenesis.

scholarly journals Isolation and characterization of antagonistic bacteria with the potential for biocontrol of soil-borne wheat diseases

2018 ◽  
Author(s):  
Xiaohui Wang ◽  
Changdong Wang ◽  
Chao Ji ◽  
Qian Li ◽  
Jiamiao Zhang ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Acetic Acid ◽  
Plant Growth ◽  
Plant Diseases ◽  
Control Group ◽  
Growth Promoter ◽  
Isolation And Characterization ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid

AbstractBacillus amyloliquefaciens subsp. plantarum XH-9 is a plant-beneficial rhizobacterium that shows good antagonistic potential against phytopathogens by releasing diffusible and volatile antibiotics, and secreting hydrolytic enzymes. Furthermore, the XH-9 strain possesses important plant growth-promoting characteristics, including nitrogen fixation (7.92 ± 1.05 mg/g), phosphate solubilization (58.67 ± 4.20 μg/L), potassium solubilization (10.07 ± 1.26 μg/mL), and the presence of siderophores (4.92 ± 0.46 μg/mL), indole-3-acetic acid (IAA) (7.76 ± 0.51 μg/mL) and 1-aminocyclopropane-1-carboxylic acid deaminase (ACC-deaminase) (4.67 ± 1.21 nmol/[mg•h]). Moreover, the XH-9 strain showed good capacities for wheat, corn, and chili root colonization, which are critical prerequisites for controlling soil-borne diseases as a bio-control agent. Real-time quantitative polymerase chain reaction experiments showed that the amount of Fusarium oxysporum DNA associated with the XH-9 strain after treatment significantly decreased compared with control group. Accordingly, wheat plants inoculated with the XH-9 strain showed significant increases in the plant shoot heights (14.20%), root lengths (32.25%), dry biomass levels (11.93%), and fresh biomass levels (16.28%) relative to the un-inoculated plants. The results obtained in this study suggest that the XH-9 strain has potential as plant-growth promoter and biocontrol agent when applied in local arable land to prevent damage caused by F. oxysporum and other phytopathogens.ImportancePlant diseases, particularly soilborne pathogens, play a significant role in the destruction of agricultural resources. Although these diseases can be controlled to some extent with crop and fungicides, while these measures increase the cost of production, promote resistance, and lead to environmental contamination, so they are being phased out. Plant growth-promoting rhizobacteria are an alternative to chemical pesticides that can play a key role in crop production by means of siderophore and indole-3-acetic acid production, antagonism to soilborne root pathogens, phosphate and potassium solubilization, and nitrogen fixation. These rhizobacteria can also promote a beneficial change in the microorganism community by significantly reducing its pathogenic fungi component. Their use is fully in accord with the principles of sustainability.

scholarly journals Biochemical and Genetic Bases of Indole-3-Acetic Acid (Auxin Phytohormone) Degradation by the Plant-Growth-Promoting Rhizobacterium Paraburkholderia phytofirmans PsJN

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Raúl Donoso ◽  
Pablo Leiva-Novoa ◽  
Ana Zúñiga ◽  
Tania Timmermann ◽  
Gonzalo Recabarren-Gajardo ◽  
...  
Keyword(s):  
Energy Source ◽  
Gene Regulation ◽  
Acetic Acid ◽  
Plant Growth ◽  
Plant Hormone ◽  
Content Type ◽  
Gene Functions ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid

ABSTRACT Several bacteria use the plant hormone indole-3-acetic acid (IAA) as a sole carbon and energy source. A cluster of genes (named iac) encoding IAA degradation has been reported in Pseudomonas putida 1290, but the functions of these genes are not completely understood. The plant-growth-promoting rhizobacterium Paraburkholderia phytofirmans PsJN harbors iac gene homologues in its genome, but with a different gene organization and context than those of P. putida 1290. The iac gene functions enable P. phytofirmans to use IAA as a sole carbon and energy source. Employing a heterologous expression system approach, P. phytofirmans iac genes with previously undescribed functions were associated with specific biochemical steps. In addition, two uncharacterized genes, previously unreported in P. putida and found to be related to major facilitator and tautomerase superfamilies, are involved in removal of an IAA metabolite called dioxindole-3-acetate. Similar to the case in strain 1290, IAA degradation proceeds through catechol as intermediate, which is subsequently degraded by ortho-ring cleavage. A putative two-component regulatory system and a LysR-type regulator, which apparently respond to IAA and dioxindole-3-acetate, respectively, are involved in iac gene regulation in P. phytofirmans. These results provide new insights about unknown gene functions and complex regulatory mechanisms in IAA bacterial catabolism. IMPORTANCE This study describes indole-3-acetic acid (auxin phytohormone) degradation in the well-known betaproteobacterium P. phytofirmans PsJN and comprises a complete description of genes, some of them with previously unreported functions, and the general basis of their gene regulation. This work contributes to the understanding of how beneficial bacteria interact with plants, helping them to grow and/or to resist environmental stresses, through a complex set of molecular signals, in this case through degradation of a highly relevant plant hormone.

scholarly journals Identification of Genes Involved in Indole-3-Acetic Acid Biosynthesis by Gluconacetobacter diazotrophicus PAL5 Strain Using Transposon Mutagenesis

2016 ◽  
Vol 7 ◽  
Author(s):  
Elisete P. Rodrigues ◽  
Cleiton de Paula Soares ◽  
Patrícia G. Galvão ◽  
Eddie L. Imada ◽  
Jean L. Simões-Araújo ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Transposon Mutagenesis ◽  
Gluconacetobacter Diazotrophicus ◽  
Acid Biosynthesis ◽  
Indole 3 Acetic Acid

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.

scholarly journals Quorum Sensing and Indole-3-Acetic Acid Degradation Play a Role in Colonization and Plant Growth Promotion of Arabidopsis thaliana by Burkholderia phytofirmans PsJN

2013 ◽  
Vol 26 (5) ◽  
pp. 546-553 ◽  
Author(s):  
Ana Zúñiga ◽  
María Josefina Poupin ◽  
Raúl Donoso ◽  
Thomas Ledger ◽  
Nicolás Guiliani ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Quorum Sensing ◽  
Plant Growth ◽  
Growth Promotion ◽  
Auxin Signaling ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid ◽  
Burkholderia Phytofirmans Psjn

Although not fully understood, molecular communication in the rhizosphere plays an important role regulating traits involved in plant–bacteria association. Burkholderia phytofirmans PsJN is a well-known plant-growth-promoting bacterium, which establishes rhizospheric and endophytic colonization in different plants. A competent colonization is essential for plant-growth-promoting effects produced by bacteria. Using appropriate mutant strains of B. phytofirmans, we obtained evidence for the importance of N-acyl homoserine lactone-mediated (quorum sensing) cell-to-cell communication in efficient colonization of Arabidopsis thaliana plants and the establishment of a beneficial interaction. We also observed that bacterial degradation of the auxin indole-3-acetic acid (IAA) plays a key role in plant-growth-promoting traits and is necessary for efficient rhizosphere colonization. Wildtype B. phytofirmans but not the iacC mutant in IAA mineralization is able to restore promotion effects in roots of A. thaliana in the presence of exogenously added IAA, indicating the importance of this trait for promoting primary root length. Using a transgenic A. thaliana line with suppressed auxin signaling (miR393) and analyzing the expression of auxin receptors in wild-type inoculated plants, we provide evidence that auxin signaling in plants is necessary for the growth promotion effects produced by B. phytofirmans. The interplay between ethylene and auxin signaling was also confirmed by the response of the plant to a 1-aminocyclopropane-1-carboxylate deaminase bacterial mutant strain.

Effect of Pseudomonas aeruginosa ZGKD2 on the Growth of Amorpha fruticosa L in Coal Gangue

2013 ◽  
Vol 807-809 ◽  
pp. 2023-2026
Author(s):  
Yu Xiu Zhang ◽  
Pei Li Shi ◽  
Qian Zhang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Acetic Acid ◽  
Plant Growth ◽  
Root Length ◽  
Phosphate Solubilization ◽  
Fresh Weight ◽  
Amorpha Fruticosa ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid

The cadmium-resistant Pseudomonas aeruginosa strain ZGKD2 was isolated from gangue pile of coal area. Production of siderophores, indole-3-acetic acid (IAA) and the solubilization of phosphate were observed in the strain. Two types of siderophores were identified by UV spectrophotometer. The highest production of IAA and phosphate solubilization were 2.0 ug/mL and 7.2 ug/mL. The root length, plant height and fresh weight of Amorpha fruticosa L in the substrates of Coal gannue and losses were promoted after inoculation with ZGKD2. These data indicated that Pseudomonas aeruginosa strain ZGKD2 was a plant growth-promoting bacterial (PGPB).

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