Effects of potential signal transduction antagonists on phytoalexin accumulation in tobacco

Preisig, Carol L.; Moreau, Robert A.

doi:10.1016/s0031-9422(00)90451-5

Cited by 25 publications

(14 citation statements)

References 32 publications

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“…Indeed, several groups have reported that extracellular EGTA can inhibit the mobilization of selected disease resistance mechanisms (52,53). Other workers have shown that introduction of exogenous Ca 2ϩ into resting cells can initiate a defense response in the absence of the usually required elicitors (16,54).…”

Section: Fig 2 Effect Of Plant Defense Elicitors On Intracellular Cmentioning

confidence: 99%

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

Chandra

Low

1997

Journal of Biological Chemistry

147

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: Fig 2 Effect Of Plant Defense Elicitors On Intracellular Cmentioning

confidence: 99%

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

Chandra

Low

1997

Journal of Biological Chemistry

147

117

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“…Alternatively, ABA may play a role via cADP-Rib, an intracellular calcium mobilizer (Wu et al, 1997). Consistent with this hypothesis, the synthesis of sesquiterpenoid phytoalexin rishitin in potato (Zook et al, 1987) and capsidiol in tobacco (Vogeli et al, 1992;Preisig and Moreau, 1994;Tavernier et al, 1995) and in pepper (Ma, 2008) is dependent upon Ca…”

Section: Role Of Aba In Phytoalexin Productionmentioning

confidence: 74%

“…Reactive oxygen species have been implicated in the expression of EAS in tobacco (Rusterucci et al, 1996;Yin et al, 1997) and in pepper (Maldonado-Bonilla et al, 2008) and in the accumulation of capsidiol in tobacco (Perrone et al, 2003) and in pepper (Arreola-Cortés et al, 2007). In addition, it has been suggested that Ca 2+ , calmodulin, Ca 2+ -dependent protein kinases, and phosphoinositide signaling are involved in the regulation of capsidiol synthesis in tobacco (Vogeli et al, 1992;Preisig and Moreau, 1994;Tavernier et al, 1995) and in pepper (Ma, 2008).…”

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confidence: 99%

Abscisic Acid Negatively Regulates Elicitor-Induced Synthesis of Capsidiol in Wild Tobacco

et al. 2009

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In the Solanaceae, biotic and abiotic elicitors induce de novo synthesis of sesquiterpenoid stress metabolites known as phytoalexins. Because plant hormones play critical roles in the induction of defense-responsive genes, we have explored the effect of abscisic acid (ABA) on the synthesis of capsidiol, the major wild tobacco (Nicotiana plumbaginifolia) sesquiterpenoid phytoalexin, using wild-type plants versus nonallelic mutants Npaba2 and Npaba1 that are deficient in ABA synthesis. Npaba2 and Npaba1 mutants exhibited a 2-fold higher synthesis of capsidiol than wild-type plants when elicited with either cellulase or arachidonic acid or when infected by Botrytis cinerea. The same trend was observed for the expression of the capsidiol biosynthetic genes 5-epi-aristolochene synthase and 5-epi-aristolochene hydroxylase. Treatment of wild-type plants with fluridone, an inhibitor of the upstream ABA pathway, recapitulated the behavior of Npaba2 and Npaba1 mutants, while the application of exogenous ABA reversed the enhanced synthesis of capsidiol in Npaba2 and Npaba1 mutants. Concomitant with the production of capsidiol, we observed the induction of ABA 8#-hydroxylase in elicited plants. In wild-type plants, the induction of ABA 8#-hydroxylase coincided with a decrease in ABA content and with the accumulation of ABA catabolic products such as phaseic acid and dihydrophaseic acid, suggesting a negative regulation exerted by ABA on capsidiol synthesis. Collectively, our data indicate that ABA is not required per se for the induction of capsidiol synthesis but is essentially implicated in a stressresponse checkpoint to fine-tune the amplification of capsidiol synthesis in challenged plants.

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“…The rapid influx of calcium, as well as the intracellular mobilisation of calcium pools by inositol phospholipids, is of decisive significance for the induction of the defence systems. The studies by Raz and Fluhr (36) support the hypothesis that enhanced calcium levels in tobacco cells, together with a calmodulin-like factor, activate protein kinases (33). The protein phosphorylation resulting from this seems to trigger the defence mechanisms.…”

Section: Induction and Regulation Of The Intra· And Intercellular Sigmentioning

confidence: 83%

“…The phosphorylation status of proteins involved in signal transduction and resistance development rises at the same time. In addition, calcium ion influxes across the plasma membrane have been established (33). The rapid influx of calcium, as well as the intracellular mobilisation of calcium pools by inositol phospholipids, is of decisive significance for the induction of the defence systems.…”

Section: Induction and Regulation Of The Intra· And Intercellular Sigmentioning

confidence: 99%

The Regulation and Biochemical Action of Natural Fungicides in Tobacco

Eberhardt¹

1995

Beiträge Zur Tabakforschung International/Contributions to Tobacco Research

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SUMMARYThe biochemical interactions between the tobacco plant and a fungal pathogen are complex and poorly understood. Upon infection, the fungus overcomes the natural defence mechanism of the host by the lytic activity of enzymes and by suppressing the hypersensitive reaction of N. tabacum. The ability of the tobacco plant to resist a fungal attack is based on macroscopic properties and the biosynthesis of natural fungicides. The physical and biochemical character of the leaf surface (e.g. trichome exudates, cuticular components) may prevent the fungus from entering the organism. Constitutive natural fungicides such as phenolics and terpenes operate as enzyme inhibitors, or impair the germination of the fungal spores. Newly synthesized polysaccharides of the cell wall of leaf cells may delay the penetration of the fungus. Lignification of the surrounding cells occurs to protect the healthy tissue against attack. Toxic substances created during the melanization process of the tobacco plant can destroy the fungal cells. Biosynthesis of natural fungicides, such as phytoalexins, pathogenesis-related proteins and proteinase inhibitors is induced by exogenous or endogenous elicitors. These active protection systems may interfere with the fungal metabolism. Phytoalexins and patho-""Received: 22th March 1995 ·accepted: 18th September 1995 genesis-related proteins are highly effective defence responses which offer a broad spectrum of variability and resistance against a fungal infection. New strategies for engineering crop protection are based on these defence systems. ZUSAMMENFASSUNG

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Effects of potential signal transduction antagonists on phytoalexin accumulation in tobacco

Cited by 25 publications

References 32 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

Abscisic Acid Negatively Regulates Elicitor-Induced Synthesis of Capsidiol in Wild Tobacco

The Regulation and Biochemical Action of Natural Fungicides in Tobacco

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