scholarly journals The biocontrol endophytic bacterium Pseudomonas fluorescens PICF7 induces systemic defense responses in aerial tissues upon colonization of olive roots

2014 ◽  
Vol 5 ◽  
Author(s):  
Carmen Gómez-Lama Cabanás ◽  
Elisabetta Schilirò ◽  
Antonio Valverde-Corredor ◽  
Jesús Mercado-Blanco
Keyword(s):  
Pseudomonas Fluorescens ◽  
Endophytic Bacterium ◽  
Defense Responses

scholarly journals Defense Responses of Fusarium oxysporum to 2,4-Diacetylphloroglucinol, a Broad-Spectrum Antibiotic Produced by Pseudomonas fluorescens

2004 ◽  
Vol 17 (11) ◽  
pp. 1201-1211 ◽  
Author(s):  
Alexander Schouten ◽  
Grardy van den Berg ◽  
Véronique Edel-Hermann ◽  
Christian Steinberg ◽  
Nadine Gautheron ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Pseudomonas Fluorescens ◽  
Broad Spectrum ◽  
Acid Production ◽  
Fusaric Acid ◽  
Geographic Origin ◽  
Intergenic Spacer ◽  
Pathogenic Fungi ◽  
Defense Responses ◽  
Broad Spectrum Antibiotic

A collection of 76 plant-pathogenic and 41 saprophytic Fusarium oxysporum strains was screened for sensitivity to 2,4-diacetylphloroglucinol (2,4-DAPG), a broad-spectrum antibiotic produced by multiple strains of antagonistic Pseudomonas fluorescens. Approximately 17% of the F. oxysporum strains were relatively tolerant to high 2,4-DAPG concentrations. Tolerance to 2,4-DAPG did not correlate with the geographic origin of the strains, formae speciales, intergenic spacer (IGS) group, or fusaric acid production levels. Biochemical analysis showed that 18 of 20 tolerant F. oxysporum strains were capable of metabolizing 2,4-DAPG. For two tolerant strains, analysis by mass spectrometry indicated that deacetylation of 2,4-DAPG to the less fungitoxic derivatives monoacetylphloroglucinol and phloroglucinol is among the initial mechanisms of 2,4-DAPG degradation. Production of fusaric acid, a known inhibitor of 2,4-DAPG biosynthesis in P. fluorescens, differed considerably among both 2,4-DAPG-sensitive and -tolerant F. oxysporum strains, indicating that fusaric acid production may be as important for 2,4-DAPG-sensitive as for -tolerant F. oxysporum strains. Whether 2,4-DAPG triggers fusaric acid production was studied for six F. oxysporum strains; 2,4-DAPG had no significant effect on fusaric acid production in four strains. In two strains, however, sublethal concentrations of 2,4-DAPG either enhanced or significantly decreased fusaric acid production. The implications of 2,4-DAPG degradation, the distribution of this trait within F. oxysporum and other plant-pathogenic fungi, and the consequences for the efficacy of biological control are discussed.

scholarly journals Pseudomonas fluorescens MZ05 Enhances Resistance against Setosphaeria turcica by Mediating Benzoxazinoid Metabolism in the Maize Inbred Line Anke35

Agriculture ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 32 ◽  
Author(s):  
Cheng Zhou ◽  
Zhongyou Ma ◽  
Xiaoming Lu ◽  
Lin Zhu ◽  
Congsheng Yan
Keyword(s):  
Pseudomonas Fluorescens ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Defense Responses ◽  
Setosphaeria Turcica ◽  
Disease Occurrence ◽  
Induced Disease Resistance ◽  
Foliar Pathogen ◽  
Maize Plants ◽  
Leaf Pathogen

Beneficial rhizobacteria can inhibit foliar pathogen infection by activation of defense responses, yet it the mechanisms of rhizobacteria-induced disease resistance remain largely unknown. Here, inoculation of susceptible maize plants with Pseudomonas fluorescens MZ05 significantly reduced disease occurrence caused by the leaf pathogen Setosphaeria turcica. Gene expression profiles of MZ05-inoculated plants were investigated by RNA-sequencing analyses, showing that several differentially expressed genes were positively associated with the metabolic processes of benzoxazinoids. Accordantly, the inoculation with P. fluorescens MZ05 resulted in a significant increase in the levels of 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) in the maize leaves. Furthermore, pre-inoculation with P. fluorescens MZ05 enhanced the transcription of two defense-related marked genes PAL and PR2a, as well as BX2 and GLU2, which are involved in DIMBOA biosynthesis, in pathogen-infected leaves. Defense responses in the inoculated plants were also greatly stronger and quicker than that in non-inoculated plants after pathogen attacks. However, virus-mediated silencing of BX2 or GLU2 remarkably attenuated the MZ05-induced effects, as evidenced by more disease occurrence and lower transcription of PAL and PR2a. Collectively, these findings indicated that the MZ05-induced increases of DIMBOA levels participated in the mediation of priming, which was the key mechanism in the rhizobacteria-induced host resistance.

scholarly journals Genetic Responses Induced in Olive Roots upon Colonization by the Biocontrol Endophytic Bacterium Pseudomonas fluorescens PICF7

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e48646 ◽  
Author(s):  
Elisabetta Schilirò ◽  
Massimo Ferrara ◽  
Franco Nigro ◽  
Jesús Mercado-Blanco
Keyword(s):  
Pseudomonas Fluorescens ◽  
Endophytic Bacterium ◽  
Genetic Responses

Bacterial endophytes in cotton: location and interaction with other plant-associated bacteria

1997 ◽  
Vol 43 (3) ◽  
pp. 254-259 ◽  
Author(s):  
A. Quadt-Hallmann ◽  
J. Hallmann ◽  
J. W. Kloepper
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Plant Pathogens ◽  
Biological Control Agent ◽  
Leaf Tissue ◽  
Endophytic Bacterium ◽  
Epidermal Cells ◽  
Control Activity ◽  
Associated Bacteria ◽  
Internal Colonization

Investigations were conducted to determine if biological control agent Pseudomonas fluorescens 89B-61 could colonize cotton tissues systemically and if internal colonization by a known endophytic bacterium, Enterobacter asburiae JM22, was influenced by the presence of other plant-associated bacteria. Following seed treatment, Pseudomonas fluorescens 89B-61 colonized cotton roots both externally and internally at mean population densities of 8.7 × 105 CFU/g and 1.1 × 103 CFU/g, respectively. However, bacteria were not detected in cotyledons, leaves, or stems. After inoculation onto leaves, Pseudomonas fluorescens 89B-61 established a mean internal population density of 1.6 × 104 CFU/g leaf tissue. Following stem injection, Pseudomonas fluorescens 89B-61 did not colonize roots or leaves. Pseudomonas fluorescens 89B-61 was localized on the root surface concentrated in grooves between epidermal cells, below collapsed epidermal cells, and in intercellular spaces close to the root epidermis, as identified by immunogold labeling of the bacterial membrane. Combined application of E. asburiae JM22 with another endophyte, Paenibacillus macerans Tri2-10, resulted in significantly lower internal populations of E. asburiae JM22 compared with treatment with E. asburiae JM22 alone. However, when coinoculated with a rhizosphere colonist, Micrococcus agilis strain 2RD-11, the colonization density of E. asburiae JM22 was not negatively affected. The results suggest that the internal colonization of cotton by bacteria with biological control activity may be an important aspect in their capacity to protect host plants against plant pathogens. The extent of internal colonization was shown to be influenced by other bacterial colonists.Key words: endophytic bacteria, location, interaction, cotton.

scholarly journals Pseudomonas fluorescens PTA-CT2 Triggers Local and Systemic Immune Response Against Botrytis cinerea in Grapevine

2015 ◽  
Vol 28 (10) ◽  
pp. 1117-1129 ◽  
Author(s):  
Charlotte Gruau ◽  
Patricia Trotel-Aziz ◽  
Sandra Villaume ◽  
Fanja Rabenoelina ◽  
Christophe Clément ◽  
...  
Keyword(s):  
Immune Response ◽  
Cell Death ◽  
Pseudomonas Fluorescens ◽  
Botrytis Cinerea ◽  
Defense Responses ◽  
Systemic Resistance ◽  
Related Gene ◽  
Plant Parts ◽  
Defense Related Gene ◽  
Below Ground

Although induced systemic resistance (ISR) is well-documented in the context of plant–beneficial bacteria interactions, knowledge about the local and systemic molecular and biochemical defense responses before or upon pathogen infection in grapevine is very scarce. In this study, we first investigated the capacity of grapevine plants to express immune responses at both above- and below-ground levels upon interaction with a beneficial bacterium, Pseudomonas fluorescens PTA-CT2. We then explored whether the extent of priming state could contribute to the PTA-CT2-induced ISR in Botrytis cinerea–infected leaves. Our data provide evidence that this bacterium colonized grapevine roots but not the above-ground plant parts and altered the plant phenotype that displayed multiple defense responses both locally and systemically. The grapevine roots and leaves exhibited distinct patterns of defense-related gene expression during root colonization by PTA-CT2. Roots responded faster than leaves and some responses were more strongly upregulated in roots than in leaves and vice versa for other genes. These responses appear to be associated with some induction of cell death in roots and a transient expression of HSR, a hypersensitive response-related gene in both local (roots) and systemic (leaves) tissues. However, stilbenic phytoalexin patterns followed opposite trends in roots compared with leaves but no phytoalexin was exuded during plant-bacterium interaction, suggesting that roots could play an important role in the transfer of metabolites contributing to immune response at the systemic level. Unexpectedly, in B. cinerea–infected leaves PTA-CT2-mediated ISR was accompanied in large part by a downregulation of different defense-related genes, including HSR. Only phytoalexins and glutathion-S-transferase 1 transcripts were upregulated, while the expression of anthocyanin biosynthetic genes was maintained at a higher level than the control. This suggests that decreased expression of HSR, as a marker of cell death, and activation of secondary metabolism pathways could be responsible for a reduced B. cinerea colonization capacity in bacterized plants.

scholarly journals Pseudomonas fluorescens DN16 Enhances Cucumber Defense Responses Against the Necrotrophic Pathogen Botrytis cinerea by Regulating Thermospermine Catabolism

2021 ◽  
Vol 12 ◽  
Author(s):  
Lin Zhu ◽  
Nana Qian ◽  
Yujun Sun ◽  
Xiaoming Lu ◽  
Haiming Duan ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Botrytis Cinerea ◽  
Defense Responses ◽  
Pathogen Infection ◽  
Necrotrophic Pathogen ◽  
Catabolic Enzymes ◽  
Catabolic Genes ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related

Plants can naturally interact with beneficial rhizobacteria to mediate defense responses against foliar pathogen infection. However, the mechanisms of rhizobacteria-mediated defense enhancement remain rarely clear. In this study, beneficial rhizobacterial strain Pseudomonas fluorescens DN16 greatly increased the resistance of cucumber plants against Botrytis cinerea infection. RNA-sequencing analyses showed that several polyamine-associated genes including a thermospermine (TSpm) synthase gene (CsACL5) and polyamine catabolic genes (CsPAO1, CsPAO5, and CsCuAO1) were notably induced by DN16. The associations of TSpm metabolic pathways with the DN16-mediated cucumber defense responses were further investigated. The inoculated plants exhibited the increased leaf TSpm levels compared with the controls. Accordantly, overexpression of CsACL5 in cucumber plants markedly increased leaf TSpm levels and enhanced defense against B. cinerea infection. The functions of TSpm catabolism in the DN16-mediated defense responses of cucumber plants to B. cinerea were further investigated by pharmacological approaches. Upon exposure to pathogen infection, the changes of leaf TSpm levels were positively related to the enhanced activities of polyamine catabolic enzymes including polyamine oxidases (PAOs) and copper amine oxidases (CuAOs), which paralleled the transcription of several defense-related genes such as pathogenesis-related protein 1 (CsPR1) and defensin-like protein 1 (CsDLP1). However, the inhibited activities of polyamine catabolic enzymes abolished the DN16-induced cucumber defense against B. cinerea infection. This was in line with the impaired expression of defense-related genes in the inoculated plants challenged by B. cinerea. Collectively, our findings unraveled a pivotal role of TSpm catabolism in the regulation of the rhizobacteria-primed defense states by mediating the immune responses in cucumber plants after B. cinerea infection.

scholarly journals Synergistic Effect of Plant Defense Elicitors and Biocontrol Agents on Induction of Defense Enzymes in Pea against Downy Mildew

2021 ◽  
Author(s):  
Puja Pandey ◽  
K.P.S. Kushwaha ◽  
Vinod Upadhyay ◽  
Jyotika Purohit
Keyword(s):  
Enzyme Activity ◽  
Synergistic Effect ◽  
Oxalic Acid ◽  
Plant Defense ◽  
Pseudomonas Fluorescens ◽  
Trichoderma Harzianum ◽  
Isonicotinic Acid ◽  
Defense Responses ◽  
Fresh Weight ◽  
Challenge Inoculation

Background: Plant defense against the pathogens can be induced by using different defense inducers. Plants can be treated with elicitors for fast and more intense mobilization of defense responses which can enhance the resistance against biotic or abiotic stresses. Methods: The present study has been undertaken to evaluate the synergistic effect of different plant defense inducing chemical (Salicylic acid, Isonicotinic acid, Oxalic acid and Chitosan) and biological (Trichoderma harzianum and Pseudomonas fluorescens) elicitors. Enzyme activity was expressed as the increase in absorbance using spectrophotometer. Result: Among all the treatments the maximum PAL activity (35.58 mg/g of fresh weight) was found in case of oxalic acid but after 48 hrs its activity reduced drastically. Next to oxalic acid Pseudomonas fluorescens (31.38 mg/g of fresh weight), chitosan + Trichoderma harzianum (29.38 mg/g of fresh weight) and chitosan + Pseudomonas fluorescens (27.89 mg/g of fresh weight) showed the maximum enzyme activity. The PPO activity reached the highest at 96 hr after challenge inoculation in case of chitosan + Trichoderma harzianum (9.74 µmol/min/mg/protein) treated plants followed by Trichoderma harzianum (3.53 µmol/min/mg/protein) alone. the maximum PO activity (49.12 µmol/min/mg/protein) was found in case of chitosan + Pseudomonas fluorescens treated plants followed by chitosan (42.48 µmol/min/mg/protein) after 72 hrs. the maximum phenolics (27.53 mg/gm of fresh weight) was found in case of chitosan + Pseudomonas fluorescens after 48 hrs of treatment.

scholarly journals Heat-killed endophytic bacterium induces robust plant defense responses against important pathogens

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Roxana Portieles ◽  
Hongli Xu ◽  
Qiulin Yue ◽  
Lin Zhao ◽  
Dening Zhang ◽  
...  
Keyword(s):  
Plant Defense ◽  
Plant Disease ◽  
Control Plant ◽  
Endophytic Bacterium ◽  
Defense Responses ◽  
Plant Diseases ◽  
Plant Defense Responses ◽  
Gentisic Acid ◽  
Important Challenge ◽  
First Time

AbstractStress caused by pathogens strongly damages plants. Developing products to control plant disease is an important challenge in sustainable agriculture. In this study, a heat-killed endophytic bacterium (HKEB), Bacillus aryabhattai, is used to induce plant defense against fungal and bacterial pathogens, and the main defense pathways used by the HKEB to activate plant defense are revealed. The HKEB induced high protection against different pathogens through the salicylic and jasmonic acid pathways. We report the presence of gentisic acid in the HKEB for the first time. These results show that HKEBs may be a useful tool for the management of plant diseases.

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