scholarly journals Induction of resistance to fire blight in apple (Erwinia amylovora)

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. S126-S127
Author(s):  
J.P. Paulin ◽  
R. Chartier ◽  
M. Tharaud ◽  
C. Heintz ◽  
V. Karniewicz ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Defense Responses ◽  
Infection Process ◽  
Induction Of Resistance ◽  
Abiotic And Biotic Elicitors ◽  
Different Levels

Apple genotypes show different levels of resistance to fire blight caused by the bacterium E. amylovora. This resistance is considered to be polygenic, thus relying on a number of defense mechanisms. On the assumption that in susceptible genotypes these defenses may be present but not activated during the infection process, we attempted their induction by various abiotic and biotic elicitors. Two kinds of experiments were performed in the greenhouse and in the orchard: i) evaluation after controlled inoculation of the level of protection conferred to the plant by each elicitor and ii) investigation of various defense responses potentially involved in the protection. Results showed that some elicitors provided a level of overall protection of about 50% in the orchard while higher levels may be obtained on seedlings in the greenhouse. The comparison of some defense responses in protected and unprotected treated plants showed that i) elicitation of defense is not necessarily associated with control of fire blight and that ii) some responses at least may be associated with the observed protection.

scholarly journals Modulation of Defense Responses of Malus spp. During Compatible and Incompatible Interactions with Erwinia amylovora

2002 ◽  
Vol 15 (12) ◽  
pp. 1204-1212 ◽  
Author(s):  
Jean-Stéphane Venisse ◽  
Mickaël Malnoy ◽  
Mohamed Faize ◽  
Jean-Pierre Paulin ◽  
Marie-Noëlle Brisset
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Mechanisms ◽  
Time Course ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Defense Responses ◽  
Hypersensitive Reaction ◽  
Phenylpropanoid Metabolism ◽  
Molecular Events ◽  
Incompatible Interactions

Erwinia amylovora is the causal agent of fire blight, a disease affecting members of subfamily Maloideae. In order to analyze mechanisms leading to compatible or incompatible interactions, early plant molecular events were investigated in two genotypes of Malus with contrasting susceptibility to fire blight, after confrontation with either E. amylovora or the incompatible tobacco pathogen Pseudomonas syringae pv. tabaci. Many defense mechanisms, including generation of an oxidative burst and accumulation of pathogenesis-related proteins, were elicited in both resistant and susceptible genotypes by the two pathogens at similar rates and according to an equivalent time course. This elicitation was linked with the functional hypersensitive reaction and pathogenicity (hrp) cluster of E. amylovora, because an hrp secretion mutant did not induce such responses. However, a delayed induction of several genes of various branch pathways of the phenylpropanoid metabolism was recorded in tissues of the susceptible genotype challenged with the wild-type strain of E. amylovora, whereas these genes were quickly induced in every other plant-bacteria interaction, including interactions with the hrp secretion mutant. This suggests the existence of hrp-independent elicitors of defense in the fire blight pathogen as well as hrp-dependant mechanisms of suppression of these nonspecific inductions.

Erwinia amylovora-induced defense mechanisms of two apple species that differ in susceptibility to fire blight

Plant Science ◽  
2010 ◽  
Vol 179 (1-2) ◽  
pp. 60-67 ◽  
Author(s):  
Renata Milčevičová ◽  
Christian Gosch ◽  
Heidrun Halbwirth ◽  
Karl Stich ◽  
Magda-Viola Hanke ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Induced Defense

DEFENSE MECHANISMS OF ROSACEOUS PLANTS AGAINST FIRE BLIGHT PATHOGEN ERWINIA AMYLOVORA

2014 ◽  
pp. 195-197 ◽  
Author(s):  
K. Vrancken ◽  
M. Holtappels ◽  
R. Valcke ◽  
H. Schoofs ◽  
T. Deckers ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Fire Blight ◽  
Erwinia Amylovora

scholarly journals Molecular defense responses of apple genotypes in compatible and incompatible interactions with Erwinia amylovora

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. S139-S140
Author(s):  
M.N. Brisset ◽  
J.S. Venisse ◽  
J.P. Paulin
Keyword(s):  
Pseudomonas Syringae ◽  
Type Strain ◽  
Fire Blight ◽  
Molecular Mechanisms ◽  
Erwinia Amylovora ◽  
Wild Type Strain ◽  
Defense Responses ◽  
Bacterial Disease ◽  
Wild Type ◽  
Susceptible Host

Erwinia amylovora is the causal agent of fire blight, a bacterial disease of apple and pear. Pathogenicity determinants of the bacteria are identified (hrp-dsp cluster, capsule, siderophore) but molecular mechanisms leading to susceptibility or resistance of the plant are not yet understood. To address this question, we challenged two genotypes of apple, known for their contrasting susceptibility to fire blight, with a wild-type strain of E. amylovora (Ea wt), an avirulent hrp mutant of this bacteria (Ea hrp) or a wild-type strain of the incompatible pathogen Pseudomonas syringae pv. tabaci (Pst wt). Mechanisms usually related to resistance responses were investigated i.e. oxidative stress, accumulation of PR-proteins and induction of genes encoding various enzymes of the phenylpropanoid pathway. Results showed two kinds of responses (i) some mechanisms were elicited in both susceptible and resistant genotypes by Ea wt and Pst wt with similar kinetics and not induced by Ea hrp, (ii) others were specifically repressed by Ea wt in its susceptible host, when induced by Pst wt and Ea hrp. These results suggest several hypothesis about the cross-talk between E. amylovora and its host plants.

scholarly journals Testing of Czech cultivars and advanced selections of apples for fire blight (Erwinia amylovora) resistance

2011 ◽  
Vol 31 (No. 1) ◽  
pp. 7-11
Author(s):  
C. Fischer ◽  
K. Richter ◽  
J. Blažek
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Scab Resistance ◽  
Blight Resistance ◽  
The Czech Republic ◽  
Malus Floribunda ◽  
Apple Cultivars ◽  
High Level ◽  
Very High ◽  
Different Levels

Five apple cultivars from the Czech Republic and 26 selections from the same country (a majority of them were resistant to scab) were included in the present study. M. robusta strain (Nr. 5) was used as a control with the highest level of resistance to fire blight. Another 7 cultivars with different levels of resistance or susceptibility to the disease were also evaluated. Selena and Nabella were found to be resistant, whereas Angold, Resista and Topaz were susceptible. Two HL selections were previously identified as highly resistant, 3 selections as medium resistant and 7 others as moderately susceptible. The rest of the 14 selections ranged from very high susceptible to medium susceptible. A high level of resistance was confirmed in 3 cultivars from Dresden-Pillnitz: Reanda, Remo and Rewena. Comparison of the parentage of the tested cultivars or selections with their level of resistance to fire blight suggests that most of the resistance comes from Malus floribunda, which was used in the course of their breeding as a donor of scab resistance. In one case, the source of the fire blight resistance was Starking Delicious cv.  

scholarly journals An Erwinia amylovora inducible promoter for intragenic improvement of apple fire blight resistance

2019 ◽  
Author(s):  
Gaucher Matthieu ◽  
Righetti Laura ◽  
Aubourg Sébastien ◽  
Dugé de Bernonville Thomas ◽  
Brisset Marie-Noëlle ◽  
...  
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Inducible Promoter ◽  
Infection Process ◽  
Oxidative Enzymes ◽  
Regulatory Sequences ◽  
Dependent Manner ◽  
Gene Promoters ◽  
Variable Activity ◽  
Type 3

AbstractIntragenesis is an important alternative to transgenesis to produce modified plants containing native DNA only. A key point to develop such a strategy is the availability of regulatory sequences controlling the expression of the gene of interest. With the aim of finding apple gene promoters either inducible by the fire blight pathogen Erwinia amylovora (Ea) or moderately constitutive, we focused on polyphenoloxidase genes (PPO). These genes encode oxidative enzymes involved in many physiological processes and have been previously shown to be up-regulated during the Ea infection process. We found ten PPO and two PPO-like sequences in the apple genome and characterized the promoters of MdPPO16 (pPPO16) and MdKFDV02 PPO-like (pKFDV02) for their potential as Ea-inducible and low-constitutive regulatory sequences respectively. Expression levels of reporter genes fused to these promoters and transiently or stably expressed in apple were quantified after various treatments. Unlike pKFDV02 which displayed a variable activity, pPPO16 allowed a fast and strong expression of transgenes in apple following Ea infection in a Type 3 Secretion System dependent manner. Altogether our results indicate that pKFDV02 did not keep its promises as a constitutive and weak promoter whereas pPPO16, the first Ea-inducible promoter cloned from apple, can be a useful component of intragenic strategies to create fire blight resistant apple genotypes.

scholarly journals Functional characterization of the adenine transporter EaAdeP from the fire blight pathogen Erwinia amylovora and its effect on disease establishment in apples and pears

2020 ◽  
Vol 367 (20) ◽  
Author(s):  
Candace R Alexander ◽  
Regan B Huntley ◽  
Neil P Schultes ◽  
George S Mourad
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Functional Characterization ◽  
Biochemical Properties ◽  
Apple Fruit ◽  
Infection Process ◽  
Disease Symptoms ◽  
Uptake Studies ◽  
Important Disease

ABSTRACT Erwinia amylovora is the causal agent of fire blight, an economically important disease of apples and pears. As part of the infection process, Er. amylovora propagates on different plant tissues each with distinct nutrient environments. Here, the biochemical properties of the Er. amylovora adenine permease (EaAdeP) are investigated. Heterologous expression of EaAdeP in nucleobase transporter-deficient Escherichia coli strains, coupled with radiolabel uptake studies, revealed that EaAdeP is a high affinity adenine transporter with a Km of 0.43 ± 0.09 μM. Both Es. coli and Er. amylovora carrying extra copies of EaAdeP are sensitive to growth on the toxic analog 8-azaadenine. EaAdeP is expressed during immature pear fruit infection. Immature pear and apple fruit virulence assays reveal that an E. amylovora ΔadeP::Camr mutant is still able to cause disease symptoms, however, with growth at a lower level, indicating that external adenine is utilized in disease establishment.

scholarly journals 523 Prohexadione-Ca: Induction of Resistance against Bacterial and Fungal Pathogens in Apple

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 535F-536
Author(s):  
W. Rademacher ◽  
J.B. Speakman ◽  
G. Krack ◽  
M. Scholtissek ◽  
R. Wolf ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Fungal Pathogens ◽  
Fire Blight ◽  
Shoot Growth ◽  
Higher Plants ◽  
Venturia Inaequalis ◽  
Pathogen Resistance ◽  
Bactericidal Effect ◽  
Apple Tissue ◽  
Induction Of Resistance

Prohexadione-Ca (BAS 125 W) is currently developed as an inhibitor of excessive vegetative growth in apple. In addition to the control of shoot growth, pronounced effects on the incidence of scab (Venturia inaequalis) and fire blight (Erwinia amylovora) are observed that are not due to any fungicidal or bactericidal effect of the compound. Prohexadione-Ca induces marked changes in the metabolism of phenylpropanoids most likely by inhibiting distinct dioxygenases, such as flavanone 3-hydroxylase, which require 2-oxoglutarate as a co-substrate. The content of flavonoids such as luteoliflavan (which does not normally occur in apple tissue) and eriodyctiol is drastically increased reaching levels in the range of 50 mg per gram of dried young shoot tissue. Simple phenols, the identity of which is still unknown, also undergo intense changes. Since phenylpropanoids have often been found to be involved in defense mechanisms of higher plants, further studies on their role in pathogen resistance in apple are justified from these results.

Fire Blight Susceptibility in Pyrus Germplasm from Eastern Europe

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 566-568 ◽  
Author(s):  
T. van der Zwet ◽  
R.L. Bell
Keyword(s):  
Eastern Europe ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Breeding Program ◽  
Plant Germplasm ◽  
Plant Exploration ◽  
Moderately Resistant

During 1976-1980, three plant exploration trips were made throughout eastern Europe in search of native Pyrus germplasm. A total of 384 accessions (231 from Yugoslavia, 86 from Romania, 43 from Poland, and 12 each from Hungary and Czechoslovakia) were collected as budwood and propagated at the National Plant Germplasm Quarantine Center in Glenn Dale, Md. Following 8 years of exposure to the fire blight bacterium [Erwinia amylovora (Burr.) Winsl. et al.], 17.49” of the accessions remained uninfected, 11.2% rated resistant, 6.8% moderately resistant, and 64.6% blighted severely (26% to 100% of tree blighted). Some of the superior accessions have been released for use in the pear breeding program.

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