Harpin, An Elicitor of the Hypersensitive Response in Tobacco Caused by Erwinia amylovora, Elicits Active Oxygen Production in Suspension Cells

Baker, C. Jacyn; Orlandi, Elizabeth W.; Mock, Norton M.

doi:10.1104/pp.102.4.1341

Cited by 188 publications

(116 citation statements)

References 8 publications

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“…The OGA preparation used in these studies contained 0.5 mg/ml galacturonic equivalents as determined by the method of Blumenkrantz and Asboe-Hansen (41). Harpin, a potent inducer of both the oxidative burst (11,12) and the hypersensitive response (42), was a kind gift of Dr. Steven Beer (Cornell University). Mas-7, an active analog of mastoparan, and Mas-17, its inactive counterpart, were purchased from Calbiochem.…”

Section: Methodsmentioning

confidence: 99%

“…a pathway commonly inaugurated by Ca 2ϩ channels (47). Finally, harpin, a heat stable protein from the bacteria E. amylovora was chosen, because it induces the oxidative burst (11,12) and may promote the hypersensitive response (42,48) in tobacco. Importantly, in addition to serving as potent inducers of the oxidative burst, all of the above elicitors are available in relatively pure form, confirming that any Ca 2ϩ transients observed will have been induced by the same component in the preparation that is responsible for stimulating the oxidative burst.…”

Section: Some Elicitors Of the Oxidative Burst Induce A Ca 2ϩmentioning

confidence: 99%

“…Within minutes of pathogen recognition, reactive oxygen species are generated that may promote cross-linking and lignification of the cell wall (2,3), transcription of defense-related genes (4,5), secondary metabolite biosynthesis (6), the hypersensitive response (4,7,8), and direct pathogen cytotoxicity (9,10), depending on the plant species examined. In cultured cell systems, the oxidative burst can be promoted by isolated elicitors including harpin (11,12), oligouronides (13), elicitins (14), purified fungal peptides (15), and other molecules from the extracts of pathogens (7,16). Abiotic stimuli such as mechanical stress (17), the pesticide fenthion (18), cold shock (19), phosphatase inhibitors (4,20), and hypo-osmotic stress (17) can also induce biosynthesis of reactive oxygen species in plant cells.…”

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confidence: 99%

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Measurement of Ca2+ Fluxes during Elicitation of the Oxidative Burst in Aequorin-transformed Tobacco Cells

Chandra

Low

1997

Journal of Biological Chemistry

148

117

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We have employed suspension cultured aequorintransformed tobacco cells to examine the involvement of Ca 2؉ in signal transduction of the oxidative burst. Use of cultured cells for this purpose was validated by demonstrating that the cells responded to cold shock quantitatively and qualitatively similarly to the intact transgenic plants from which they were derived. Stimulation of the oxidative burst in the cell suspension was achieved by administration of oligogalacturonic acid, Mas-7 (a peptide known to activate G proteins and Ca 2؉ fluxes), hypo-osmotic stress, or harpin (a protein from the pathogenic bacterium Erwinia amylovora). The latter failed to promote any detectable increase in cytoplasmic Ca 2؉ concentration, whereas each of the former three triggered a rapid rise in cytosolic Ca 2؉ followed by a return within seconds to basal Ca 2؉ levels. Peak Ca 2؉ concentrations induced by the former three elicitors were ϳ0.7, 1.4, and 1.3 M, respectively. Three lines of evidence suggest that the observed Ca 2؉ pulses are essential to transduction of the oxidative burst signals by their respective elicitors: (i) inhibition of the Ca 2؉ transients with Ca 2؉ chelators or Ca 2؉ channel blockers prevented expression of the oxidative burst, (ii) introduction of exogenous Ca 2؉ into the same cells initiated the burst even in the absence of other inducers of the response, and (iii) the observed Ca 2؉ transients often returned to near basal levels well before any H 2 O 2 synthesis could be detected, suggesting that the Ca 2؉ influx is required to communicate the burst signal but not maintain the defense response. These data suggest that Ca 2؉ pulses serve frequently, but not invariably, to transduce an oxidative burst signal.The oxidative burst constitutes one of the more rapid responses of a plant cell to pathogen attack (1). Within minutes of pathogen recognition, reactive oxygen species are generated that may promote cross-linking and lignification of the cell wall (2, 3), transcription of defense-related genes (4, 5), secondary metabolite biosynthesis (6), the hypersensitive response (4,7,8), and direct pathogen cytotoxicity (9, 10), depending on the plant species examined. In cultured cell systems, the oxidative burst can be promoted by isolated elicitors including harpin (11, 12), oligouronides (13), elicitins (14), purified fungal peptides (15), and other molecules from the extracts of pathogens (7,16). Abiotic stimuli such as mechanical stress (17), the pesticide fenthion (18), cold shock (19), phosphatase inhibitors (4, 20), and hypo-osmotic stress (17) can also induce biosynthesis of reactive oxygen species in plant cells.Because of its rapid expression, ease of assay, and similarity to the analogous defense response in human neutrophils (21), the oxidative burst has recently served as a model for exploring signal transduction pathways in plants. As the numbers of elicitors examined have risen, it has become increasingly clear that different elicitors may inaugurate independent signal transduction pathways that...

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Section: Methodsmentioning

confidence: 99%

Section: Some Elicitors Of the Oxidative Burst Induce A Ca 2ϩmentioning

confidence: 99%

mentioning

confidence: 99%

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Measurement of Ca2+ Fluxes during Elicitation of the Oxidative Burst in Aequorin-transformed Tobacco Cells

Chandra

Low

1997

Journal of Biological Chemistry

148

117

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“…Although identified several years ago, the roles of these proteins during colonization of host plants and their site of action have remained unclear. However, when infiltrated into nonhost plants, harpins trigger disease resistance-associated responses, such as HR, transcript accumulation of pathogenesis-related ( PR ) genes, and systemic acquired resistance (Baker et al, 1993;He et al, 1993;Gopalan et al, 1996;Strobel et al, 1996;Dong et al, 1999;Galan and Collmer, 1999). Physiological target sites for harpin action, therefore, were suggested to reside at the plant cell surface.…”

Section: Introductionmentioning

confidence: 99%

A Harpin Binding Site in Tobacco Plasma Membranes Mediates Activation of the Pathogenesis-Related Gene HIN1 Independent of Extracellular Calcium but Dependent on Mitogen-Activated Protein Kinase Activity

Lee¹,

Klessig²,

Nürnberger³

2001

The Plant Cell

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Harpin from the bean halo-blight pathogen Pseudomonas syringae pv phaseolicola (harpin Psph ) elicits the hypersensitive response and the accumulation of pathogenesis-related gene transcripts in the nonhost plant tobacco. Here, we report the characterization of a nonproteinaceous binding site for harpin Psph in tobacco plasma membranes, which is assumed to mediate the activation of plant defense responses in a receptor-like manner. Binding of 125 I-harpin Psph to tobacco microsomal membranes (dissociation constant ‫؍‬ 425 nM) and protoplasts (dissociation constant ‫؍‬ 380 nM) was specific, reversible, and saturable. A close correlation was found between the abilities of harpin Psph fragments to elicit the transcript accumulation of the pathogenesis-related tobacco gene HIN1 and to compete for binding of 125 Iharpin Psph to its binding site. Another elicitor of the hypersensitive response and HIN1 induction in tobacco, the Phytophthora megasperma -derived ␤ -elicitin ␤ -megaspermin, failed to bind to the putative harpin Psph receptor. In contrast to activation by ␤ -megaspermin, harpin Psph -induced activation of the 48-kD salicylic acid-responsive mitogen-activated protein kinase (MAPK) and HIN1 transcript accumulation were independent of extracellular calcium. Moreover, use of the MAPK kinase inhibitor U0126 revealed that MAPK activity was essential for pathogenesis-related gene expression in harpin Psph -treated tobacco cells. Thus, a receptor-mediated MAPK-dependent signaling pathway may mediate the activation of plant defense responses induced by harpin Psph .

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“…The elicitors induced the production of reactive oxygen species, including H 2 O 2 , and caused increases in glutathione levels and lipoxygenase enzyme activity. Kieffer et al [54] demonstrated the possible involve- shown to induce AOS production and K + /H + exchange in a tobacco cell-suspension system [55]. Harpin has been shown to elicit the hypersensitive response in tobacco and other non-host species [56,57].…”

Section: Cell Culture Experimentsmentioning

confidence: 99%

Induction of defense responses in tobacco by the protein Nep1 from Fusarium oxysporum

et al. 2001

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Harpin, An Elicitor of the Hypersensitive Response in Tobacco Caused by Erwinia amylovora, Elicits Active Oxygen Production in Suspension Cells

Cited by 188 publications

References 8 publications

Measurement of Ca2+ Fluxes during Elicitation of the Oxidative Burst in Aequorin-transformed Tobacco Cells

Measurement of Ca2+ Fluxes during Elicitation of the Oxidative Burst in Aequorin-transformed Tobacco Cells

A Harpin Binding Site in Tobacco Plasma Membranes Mediates Activation of the Pathogenesis-Related Gene HIN1 Independent of Extracellular Calcium but Dependent on Mitogen-Activated Protein Kinase Activity

Induction of defense responses in tobacco by the protein Nep1 from Fusarium oxysporum

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