scholarly journals Galactinol Is a Signaling Component of the Induced Systemic Resistance Caused by Pseudomonas chlororaphis O6 Root Colonization

2008 ◽  
Vol 21 (12) ◽  
pp. 1643-1653 ◽  
Author(s):  
Mi Seong Kim ◽  
Song Mi Cho ◽  
Eun Young Kang ◽  
Yang Ju Im ◽  
Hoon Hwangbo ◽  
...  
Keyword(s):  
Root Colonization ◽  
Induced Systemic Resistance ◽  
Systemic Resistance ◽  
Suppressive Subtractive Hybridization ◽  
Transcriptional Level ◽  
Hybridization Technique ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Water Control ◽  
Tobacco Plants

Root colonization by Pseudomonas chlororaphis O6 in cucumber elicited an induced systemic resistance (ISR) against Corynespora cassiicola. In order to gain insight into O6-mediated ISR, a suppressive subtractive hybridization technique was applied and resulted in the isolation of a cucumber galactinol synthase (CsGolS1) gene. The transcriptional level of CsGolS1 and the resultant galactinol content showed an increase several hours earlier under O6 treatment than in the water control plants following C. cassiicola challenge, whereas no difference was detected in the plants without a pathogen challenge. The CsGolS1-overexpressing transgenic tobacco plants demonstrated constitutive resistance against the pathogens Botrytis cinerea and Erwinia carotovora, and they also showed an increased accumulation in galactinol content. Pharmaceutical application of galactinol enhanced the resistance against pathogen infection and stimulated the accumulation of defense-related gene transcripts such as PR1a, PR1b, and NtACS1 in wild-type tobacco plants. Both the CsGolS1-overexpressing transgenic plants and the galactinol-treated wild-type tobacco plants also demonstrated an increased tolerance to drought and high salinity stresses.

Multiple determinants influence root colonization and induction of induced systemic resistance by Pseudomonas chlororaphis O6

2006 ◽  
Vol 7 (6) ◽  
pp. 463-472 ◽  
Author(s):  
SONG HEE HAN ◽  
ANNE J. ANDERSON ◽  
KWANG YEOL YANG ◽  
BAIK HO CHO ◽  
KIL YONG KIM ◽  
...  
Keyword(s):  
Root Colonization ◽  
Induced Systemic Resistance ◽  
Systemic Resistance ◽  
Pseudomonas Chlororaphis

scholarly journals Induced Systemic Resistance in Arabidopsis thaliana Against Pseudomonas syringae pv. tomato by 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens

2012 ◽  
Vol 102 (4) ◽  
pp. 403-412 ◽  
Author(s):  
David M. Weller ◽  
Dmitri V. Mavrodi ◽  
Johan A. van Pelt ◽  
Corné M. J. Pieterse ◽  
Leendert C. van Loon ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Fluorescens ◽  
Induced Resistance ◽  
Pseudomonas Syringae ◽  
Induced Systemic Resistance ◽  
Signal Transduction Pathway ◽  
Systemic Resistance ◽  
Wild Type ◽  
Challenge Inoculation ◽  
Dependent Signal

Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are among the most effective rhizobacteria that suppress root and crown rots, wilts, and damping-off diseases of a variety of crops, and they play a key role in the natural suppressiveness of some soils to certain soilborne pathogens. Root colonization by 2,4-DAPG-producing P. fluorescens strains Pf-5 (genotype A), Q2-87 (genotype B), Q8r1-96 (genotype D), and HT5-1 (genotype N) produced induced systemic resistance (ISR) in Arabidopsis thaliana accession Col-0 against bacterial speck caused by P. syringae pv. tomato. The ISR-eliciting activity of the four bacterial genotypes was similar, and all genotypes were equivalent in activity to the well-characterized strain P. fluorescens WCS417r. The 2,4-DAPG biosynthetic locus consists of the genes phlHGF and phlACBDE. phlD or phlBC mutants of Q2-87 (2,4-DAPG minus) were significantly reduced in ISR activity, and genetic complementation of the mutants restored ISR activity back to wild-type levels. A phlF regulatory mutant (overproducer of 2,4-DAPG) had ISR activity equivalent to the wild-type Q2-87. Introduction of DAPG into soil at concentrations of 10 to 250 μM 4 days before challenge inoculation induced resistance equivalent to or better than the bacteria. Strain Q2-87 induced resistance on transgenic NahG plants but not on npr1-1, jar1, and etr1 Arabidopsis mutants. These results indicate that the antibiotic 2,4-DAPG is a major determinant of ISR in 2,4-DAPG-producing P. fluorescens, that the genotype of the strain does not affect its ISR activity, and that the activity induced by these bacteria operates through the ethylene- and jasmonic acid-dependent signal transduction pathway.

scholarly journals Root Colonization by Phenazine-1-Carboxamide-Producing Bacterium Pseudomonas chlororaphis PCL1391 Is Essential for Biocontrol of Tomato Foot and Root Rot

2000 ◽  
Vol 13 (12) ◽  
pp. 1340-1345 ◽  
Author(s):  
Thomas F. C. Chin-A-Woeng ◽  
Guido V. Bloemberg ◽  
Ine H. M. Mulders ◽  
Linda C. Dekkers ◽  
Ben J. J. Lugtenberg
Keyword(s):  
Root Rot ◽  
Root Colonization ◽  
Root Tip ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Animal Tissues ◽  
Tomato Seedling ◽  
Antifungal Metabolites ◽  
Seedling Inoculation ◽  
First Time

The phenazine-1-carboxamide-producing bacterium Pseudomonas chlororaphis PCL1391 controls tomato foot and root rot caused by Fusarium oxysporum f. sp. radicis-lycopersici. To test whether root colonization is required for biocontrol, mutants impaired in the known colonization traits motility, prototrophy for amino acids, or production of the site-specific recombinase, Sss/XerC were tested for their root tip colonization and biocontrol abilities. Upon tomato seedling inoculation, colonization mutants of strain PCL1391 were impaired in root tip colonization in a gnotobiotic sand system and in potting soil. In addition, all mutants were impaired in their ability to control tomato foot and root rot, despite the fact that they produce wild-type levels of phenazine-1-carboxamide, the antifungal metabolite previously shown to be required for biocontrol. These results show, for what we believe to be the first time, that root colonization plays a crucial role in biocontrol, presumably by providing a delivery system for antifungal metabolites. The ability to colonize and produce phenazine-1-carboxamide is essential for control of F. oxysporum f. sp. radicis-lycopersici. Furthermore, there is a notable overlap of traits identified as being important for colonization of the rhizosphere and animal tissues.

scholarly journals IDENTIFICATION AND QUANTIFICATION OF DIFFERENTIALLY EXPRESSED GENES ASSOCIATED WITH CITRUS BLIGHT (Citrus spp.)

2015 ◽  
Vol 39 (1) ◽  
pp. 32-38
Author(s):  
José Renato de Abreu ◽  
Luciano Vilela Paiva ◽  
Miguel Angel Dita Rodríguez ◽  
Anderson Tadeu Silva ◽  
Ariadne Ribeiro Henriques ◽  
...  
Keyword(s):  
Stress Responses ◽  
Plant Stress ◽  
Control Measures ◽  
Differentially Expressed ◽  
Cdna Libraries ◽  
Suppressive Subtractive Hybridization ◽  
Transcriptional Level ◽  
Hybridization Technique ◽  
Tree Roots ◽  
Citrus Blight

Brazil is the largest citrus producer in the world, being responsible for more than 20% of its production, which is, however still low due to phytosanitary issues such as citrus blight. Citrus blight is an anomaly whose causes still have not yet been determined, therefore there are no efficient control measures to minimize the production losses with the use of resistant varieties being considered the most appropriate method. However, little is known about the genes involved in the defense response of the plants to this anomaly. Considering that many physiological alterations associated with plant stress responses are controlled at a transcriptional level, in this study we sought the identification and characterization of the gene expression products differentially expressed in the response to the citrus blight. Through the suppressive subtractive hybridization technique, expressed cDNA libraries were built using mRNAs isolated from "Cravo" lemon tree roots (Citrus limonia L. Osbeck) under "Pera" orange (Citrus sinensis L. Osbeck) of healthy and sick plants. 129 clones were obtained by subtraction and their sequences were compared in databases. 34 of them linked to proteins associated to stress processes, while the others were similar to sequences of unknown functions or did not present similarity with sequences deposited in the databases. 3 genes were selected and their expressions were studied by RT - qPCR in real-time. Plants with citrus blight presented an increase of the expression level in two of those genes, suggesting that these can be directly involved with this anomaly.

The global regulator GacS regulates biofilm formation in Pseudomonas chlororaphis O6 differently with carbon source

2014 ◽  
Vol 60 (3) ◽  
pp. 133-138 ◽  
Author(s):  
Ji Soo Kim ◽  
Yong Hwan Kim ◽  
Ju Yeon Park ◽  
Anne J. Anderson ◽  
Young Cheol Kim
Keyword(s):  
Carbon Source ◽  
Biofilm Formation ◽  
Defined Medium ◽  
Root Surface ◽  
Gray Mold ◽  
Systemic Resistance ◽  
Pseudomonas Chlororaphis ◽  
Wild Type ◽  
Tomato Leaf Mold ◽  
Phenazine Production

An aggressive root colonizer, Pseudomonas chlororaphis O6 produces various secondary metabolites that impact plant health. The sensor kinase GacS is a key regulator of the expression of biocontrol-related traits. Biofilm formation is one such trait because of its role in root surface colonization. This paper focuses on the effects of carbon source on biofilm formation. In comparison with the wild type, a gacS mutant formed biofilms at a reduced level with sucrose as the major carbon source but at much higher level with mannitol in the defined medium. Biofilm formation by the gacS mutant occurred without phenazine production and in the absence of normal levels of acyl homoserine lactones, which promote biofilms with other pseudomonads. Colonization of tomato roots was similar for the wild type and gacS mutant, showing that any differences in biofilm formation in the rhizosphere were not of consequence under the tested conditions. The reduced ability of the gacS mutant to induce systemic resistance against tomato leaf mold and tomato gray mold was consistent with a lack of production of effectors, such as phenazines. These results demonstrated plasticity in biofilm formation and root colonization in the rhizosphere by a beneficial pseudomonad.

scholarly journals Role of Iron in Rhizobacteria-Mediated Induced Systemic Resistance of Cucumber

2001 ◽  
Vol 91 (6) ◽  
pp. 593-598 ◽  
Author(s):  
C. M. Press ◽  
J. E. Loper ◽  
J. W. Kloepper
Keyword(s):  
Serratia Marcescens ◽  
Induced Systemic Resistance ◽  
Iron Concentration ◽  
Iron Chelator ◽  
Disease Suppression ◽  
Systemic Resistance ◽  
Wild Type ◽  
Rhizosphere Bacterium ◽  
Population Sizes ◽  
External Population

Seed treatment with the rhizosphere bacterium Serratia marcescens strain 90-166 suppressed anthracnose of cucumber, caused by Colleto-trichum orbiculare, through induced systemic resistance (ISR). When the iron concentration of a planting mix was decreased by addition of an iron chelator, suppression of cucumber anthracnose by strain 90-166 was significantly improved. Strain 90-166 produced 465 ± 70 mg/liter of catechol siderophore, as determined by the Rioux assay in deferrated King's medium B. The hypothesis that a catechol siderophore produced by strain 90-166 may be responsible for induction of systemic resistance by this strain was tested by evaluating disease suppression by a mini-Tn5-phoA mutant deficient in siderophore production. Sequence analysis of genomic DNA flanking the mini-Tn5-phoA insertion identified the target gene as entA, which encodes an enzyme in the catechol siderophore biosynthetic pathways of several bacteria. Severity of anthracnose of cucumbers treated with the entA mutant was not significantly different (P = 0.05) from the control, whereas plants treated with wild-type 90-166 had significantly less disease (P = 0.05) than the control. Total (internal and external) population sizes of 90-166 and the entA mutant on roots did not differ significantly (P = 0.05) at any sample time, whereas internal population sizes of the entA mutant were significantly lower (P = 0.05) than those of the wild-type strain at two sampling times. These data suggest that catechol siderophore biosynthesis genes in Serratia marcescens 90-166 are associated with ISR but that this role may be indirect via a reduction in internal root populations.

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