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The bacterial plant pathogen, Erwinia amylovora, causes the devastating disease known as fire blight in some Rosaceous plants like apple, pear, quince, raspberry and several ornamentals. Knowledge of the factors affecting the development of fire blight has mushroomed in the last quarter century. On the molecular level, genes encoding a Hrp type III(More)
Erwinia amylovora causes the economically important disease fire blight that affects rosaceous plants, especially pear and apple. Here we report the complete genome sequence and annotation of strain ATCC 49946. The analysis of the sequence and its comparison with sequenced genomes of closely related enterobacteria revealed signs of pathoadaptation to(More)
HrpN (harpin) protein is critical to the virulence of the fire blight pathogen Erwinia amylovora in host plants like apple (Malus x domestica). Moreover, exogenous treatment of Arabidopsis (Arabidopsis thaliana), a nonhost plant, with partially purified HrpN enhances growth. To address the bases of the effects of HrpN in disease, we sought a(More)
Ethylene (ET) signal transduction may regulate plant growth and defense, depending on which components are recruited into the pathway in response to different stimuli. We report here that the ET pathway controls both insect resistance (IR) and plant growth enhancement (PGE) in Arabidopsis (Arabidopsis thaliana) plants responding to harpin, a protein(More)
ABSTRACT The role of riboflavin as an elicitor of systemic resistance and an activator of a novel signaling process in plants was demonstrated. Following treatment with riboflavin, Arabidopsis thaliana developed systemic resistance to Peronospora parasitica and Pseudomonas syringae pv. Tomato, and tobacco developed systemic resistance to Tobacco mosaic(More)
A proteinaceous elicitor of the plant defense reaction known as the hypersensitive response was isolated from Erwinia amylovora, the bacterium that causes fire blight of pear, apple, and other rosaceous plants. The elicitor, named harpin, is an acidic, heat-stable, cell-envelope-associated protein with an apparent molecular weight of 44 kilodaltons. Harpin(More)
Harpin, the product of the hrpN gene of Erwinia amylovora, elicits the hypersensitive response and disease resistance in many plants. Harpin and known inducers of systemic acquired resistance (SAR) were tested on five genotypes of Arabidopsis thaliana to assess the role of SAR in harpin-induced resistance. In wild-type plants, harpin elicited systemic(More)
Unlike the bacterial pathogens that typically cause the hypersensitive response (HR) in plants, Erwinia chrysanthemi has a wide host range, rapidly kills and macerates host tissues, and secretes several isozymes of the macerating enzyme pectate lyase (Pel). PelABCE- and Out- (secretion-deficient) mutants were observed to produce a rapid necrosis in tobacco(More)
Harpin proteins from gram-negative plant-pathogenic bacteria can stimulate hypersensitive cell death (HCD) and pathogen defense as well as enhance growth in plants. Two of these diverse activities clearly are beneficial and may depend on particular functional regions of the proteins. Identification of beneficial and deleterious regions might facilitate the(More)
SUMMARY Sequence analysis of the region bordering the hrp/dsp gene cluster of Erwinia amylovora strain Ea321, which causes fire blight, revealed characteristics of pathogenicity islands (PAIs). Included are genes for a phage integrase, a tRNA(Phe), several orthologues of genes of YAPI, a PAI of Yersinia pseudotuberculosis, and several putative virulence(More)