scholarly journals Salicylic Acid Produced by Serratia marcescens 90-166 Is Not the Primary Determinant of Induced Systemic Resistance in Cucumber or Tobacco

1997 ◽  
Vol 10 (6) ◽  
pp. 761-768 ◽  
Author(s):  
C. M. Press ◽  
M. Wilson ◽  
S. Tuzun ◽  
J. W. Kloepper
Keyword(s):  
Salicylic Acid ◽  
Serratia Marcescens ◽  
Pseudomonas Syringae ◽  
Ferric Iron ◽  
Induced Systemic Resistance ◽  
Iron Concentration ◽  
Systemic Resistance ◽  
Broth Culture ◽  
In Planta

The rhizobacterial strain Serratia marcescens 90–66 mediates induced systemic resistance (ISR) to fungal, bacterial, and viral pathogens. It was determined that strain 90–166 produced salicylic acid (SA), using the salicylateresponsive reporter plasmid pUTK21. High-pressure liquid chromatography analysis of culture extracts confirmedthe production of SA in broth culture. Mini-Tn5phoA mutants, which did not produce detectable amounts of SA, retained ISR activity in cucumber against the fungal pathogen Colletotrichum orbiculare. Strain 90–166 induced disease resistance to Pseudomonas syringae pv. tabaci in wild-type Xanthi-nc and transgenic NahG-10 tobacco expressing salicylate hydroxylase. Increasing ferric iron concentrations in vitro reduced SA production below detectable limits, and increasing ferric iron concentration in planta, applied as a root drench, significantly reduced the level of ISR observed in cucumber to C. orbiculare. An ISR¯ mutant (90-166-2882) still produced SA. The results of this study indicate that SA produced by 90–166 is not the primary bacterial determinant of ISR and that this bacterial-mediated ISR system is affected by iron concentration.

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.

scholarly journals No Role for Bacterially Produced Salicylic Acid in Rhizobacterial Induction of Systemic Resistance in Arabidopsis

2005 ◽  
Vol 95 (11) ◽  
pp. 1349-1355 ◽  
Author(s):  
L. X. Ran ◽  
L. C. van Loon ◽  
P. A. H. M. Bakker
Keyword(s):  
Salicylic Acid ◽  
Induced Systemic Resistance ◽  
Incubation Temperature ◽  
Growth Conditions ◽  
Systemic Resistance ◽  
Bacterial Speck ◽  
Fluorescent Pseudomonas ◽  
Pathogenesis Related Protein ◽  
Induction Of Resistance

The role of bacterially produced salicylic acid (SA) in the induction of systemic resistance in plants by rhizobacteria is far from clear. The strong SA producer Pseudomonas fluorescens WCS374r induces resistance in radish but not in Arabidopsis thaliana, whereas application of SA leads to induction of resistance in both plant species. In this study, we compared P. fluorescens WCS374r with three other SA-producing fluorescent Pseudomonas strains, P. fluorescens WCS417r and CHA0r, and P. aeruginosa 7NSK2 for their abilities to produce SA under different growth conditions and to induce systemic resistance in A. thaliana against bacterial speck, caused by P. syringae pv. tomato. All strains produced SA in vitro, varying from 5 fg cell-1 for WCS417r to >25 fg cell-1 for WCS374r. Addition of 200 μM FeCl3 to standard succinate medium abolished SA production in all strains. Whereas the incubation temperature did not affect SA production by WCS417r and 7NSK2, strains WCS374r and CHA0r produced more SA when grown at 33 instead of 28°C. WCS417r, CHA0r, and 7NSK2 induced systemic resistance apparently associated with their ability to produce SA, but WCS374r did not. Conversely, a mutant of 7NSK2 unable to produce SA still triggered induced systemic resistance (ISR). The possible involvement of SA in the induction of resistance was evaluated using SA-nonaccumulating transgenic NahG plants. Strains WCS417r, CHA0r, and 7NSK2 induced resistance in NahG Arabidopsis. Also, WCS374r, when grown at 33 or 36°C, triggered ISR in these plants, but not in ethylene-insensitive ein2 or in non-plant pathogenesis- related protein-expressing npr1 mutant plants, irrespective of the growth temperature of the bacteria. These results demonstrate that, whereas WCS374r can be manipulated to trigger ISR in Arabidopsis, SA is not the primary determinant for the induction of systemic resistance against bacterial speck disease by this bacterium. Also, for the other SAproducing strains used in this study, bacterial determinants other than SA must be responsible for inducing resistance.

scholarly journals Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

2021 ◽  
Author(s):  
Mara Quaglia ◽  
Marika Bocchini ◽  
Benedetta Orfei ◽  
Roberto D’Amato ◽  
Franco Famiani ◽  
...  
Keyword(s):  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Zinc Phosphate ◽  
Plant Defence ◽  
In Planta ◽  
Tomato Plants ◽  
Pathogenesis Related Protein ◽  
Defence Responses ◽  
Plant Defence Responses

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses.

scholarly journals HopA1 Effector from Pseudomonas syringae pv syringae Strain 61 Affects NMD Processes and Elicits Effector-Triggered Immunity

2021 ◽  
Vol 22 (14) ◽  
pp. 7440
Author(s):  
Shraddha K. Dahale ◽  
Daipayan Ghosh ◽  
Kishor D. Ingole ◽  
Anup Chugani ◽  
Sang Hee Kim ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Disease Susceptibility ◽  
Null Mutant ◽  
In Planta ◽  
Host Range Expansion ◽  
Unique System ◽  
Effector Triggered Immunity ◽  
Transcriptomic Changes ◽  
Immune Detection

Pseudomonas syringae-secreted HopA1 effectors are important determinants in host range expansion and increased pathogenicity. Their recent acquisitions via horizontal gene transfer in several non-pathogenic Pseudomonas strains worldwide have caused alarming increase in their virulence capabilities. In Arabidopsis thaliana, RESISTANCE TO PSEUDOMONAS SYRINGAE 6 (RPS6) gene confers effector-triggered immunity (ETI) against HopA1pss derived from P. syringae pv. syringae strain 61. Surprisingly, a closely related HopA1pst from the tomato pathovar evades immune detection. These responsive differences in planta between the two HopA1s represents a unique system to study pathogen adaptation skills and host-jumps. However, molecular understanding of HopA1′s contribution to overall virulence remain undeciphered. Here, we show that immune-suppressive functions of HopA1pst are more potent than HopA1pss. In the resistance-compromised ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) null-mutant, transcriptomic changes associated with HopA1pss-elicited ETI are still induced and carry resemblance to PAMP-triggered immunity (PTI) signatures. Enrichment of HopA1pss interactome identifies proteins with regulatory roles in post-transcriptional and translational processes. With our demonstration here that both HopA1 suppress reporter-gene translations in vitro imply that the above effector-associations with plant target carry inhibitory consequences. Overall, with our results here we unravel possible virulence role(s) of HopA1 in suppressing PTI and provide newer insights into its detection in resistant plants.

scholarly journals The algT Gene of Pseudomonas syringae pv. glycinea andNew Insights into the Transcriptional Organization of thealgT-muc Gene Cluster

2006 ◽  
Vol 188 (23) ◽  
pp. 8013-8021 ◽  
Author(s):  
Alexander Schenk ◽  
Michael Berger ◽  
Lisa M. Keith ◽  
Carol L. Bender ◽  
Georgi Muskhelishvili ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Pseudomonas Syringae ◽  
Azotobacter Vinelandii ◽  
Regulatory Gene ◽  
In Planta ◽  
Phytopathogenic Bacterium ◽  
Reverse Transcription Pcr ◽  
Alginate Production ◽  
Alginate Biosynthesis

ABSTRACT The phytopathogenic bacterium Pseudomonas syringae pv. glycinea infects soybean plants and causes bacterial blight. In addition to P. syringae, the human pathogen Pseudomonas aeruginosa and the soil bacterium Azotobacter vinelandii produce the exopolysaccharide alginate, a copolymer of d-mannuronic and l-guluronic acids. Alginate production in P. syringae has been associated with increased fitness and virulence in planta. Alginate biosynthesis is tightly controlled by proteins encoded by the algT-muc regulatory gene cluster in P. aeruginosa and A. vinelandii. These genes encode the alternative sigma factor AlgT (σ22), its anti-sigma factors MucA and MucB, MucC, a protein with a controversial function that is absent in P. syringae, and MucD, a periplasmic serine protease and homolog of HtrA in Escherichia coli. We compared an alginate-deficient algT mutant of P. syringae pv. glycinea with an alginate-producing derivative in which algT is intact. The alginate-producing derivative grew significantly slower in vitro growth but showed increased epiphytic fitness and better symptom development in planta. Evaluation of expression levels for algT, mucA, mucB, mucD, and algD, which encodes an alginate biosynthesis gene, showed that mucD transcription is not dependent on AlgT in P. syringae in vitro. Promoter mapping using primer extension experiments confirmed this finding. Results of reverse transcription-PCR demonstrated that algT, mucA, and mucB are cotranscribed as an operon in P. syringae. Northern blot analysis revealed that mucD was expressed as a 1.75-kb monocistronic mRNA in P. syringae.

scholarly journals Transcript and metabolite analysis of the Trichoderma-induced systemic resistance response to Pseudomonas syringae in Arabidopsis thaliana

Microbiology ◽  
2012 ◽  
Vol 158 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Yariv Brotman ◽  
Jan Lisec ◽  
Michaël Méret ◽  
Ilan Chet ◽  
Lothar Willmitzer ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Induced Systemic Resistance ◽  
Systemic Resistance ◽  
Metabolite Analysis ◽  
Resistance Response

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.

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