Studies on the action of the dichlorocyclopropanes on the host-parasite relationship in the rice blast disease

Langcake, P.; Wickins, Susan G. A.

doi:10.1016/0048-4059(75)90002-8

Cited by 44 publications

(13 citation statements)

References 29 publications

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“…Serotonin feeding partially inhibited the extension of B. oryzae hyphae in plant tissues, indicating that accumulation of serotonin and deposition of brown material at the infection site are part of an effective defense mechanism. The involvement of the deposition of brown material in the defense responses of rice has been suggested in the interactions with M. grisea and X. oryzae (Kaku and Hori, 1977; Langcake and Wickins, 1975). However, serotonin feeding did not result in the complete restoration of resistance in the sl mutant despite the marked recovery of deposition of brown material.…”

Section: Discussionmentioning

confidence: 99%

“…, 1978), which has been known for almost half a century. In the interaction between rice and Magnaporthe grisea , a good correlation has been observed between the rate of accumulation of brown material and the resistance against the pathogen (Langcake and Wickins, 1975). The browning reaction was also induced by infection of X. oryzae , in which the pathogen was observed to be confined to the brown necrotic area (Kaku and Hori, 1977).…”

Section: Introductionmentioning

confidence: 99%

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The tryptophan pathway is involved in the defense responses of rice against pathogenic infection via serotonin production

et al. 2008

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SummaryThe upregulation of the tryptophan (Trp) pathway in rice leaves infected by Bipolaris oryzae was indicated by: (i) enhanced enzyme activity of anthranilate synthase (AS), which regulates metabolic flux in the Trp pathway; (ii) elevated levels of the AS (OASA2, OASB1, and OASB2) transcripts; and (iii) increases in the contents of anthranilate, indole, and Trp. The measurement of the contents of Trp-derived metabolites by highperformance liquid chromatography coupled with tandem mass spectrometry revealed that serotonin and its hydroxycinnamic acid amides were accumulated in infected leaves. Serotonin accumulation was preceded by a transient increase in the tryptamine content and by marked activation of Trp decarboxylase, indicating that enhanced Trp production is linked to the formation of serotonin from Trp via tryptamine. Feeding of radiolabeled serotonin to inoculated leaves demonstrated that serotonin is incorporated into the cell walls of lesion tissue. The leaves of a propagating-type lesion mimic mutant (sl, Sekiguchi lesion) lacked both serotonin production and deposition of unextractable brown material at the infection sites, and showed increased susceptibility to B. oryzae infection. Treating the mutant with serotonin restored deposition of brown material at the lesion site. In addition, the serotonin treatment suppressed the growth of fungal hyphae in the leaf tissues of the sl mutant. These findings indicated that the activation of the Trp pathway is involved in the establishment of effective physical defenses by producing serotonin in rice leaves.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The tryptophan pathway is involved in the defense responses of rice against pathogenic infection via serotonin production

et al. 2008

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“…Although some studies have indicated that these changes are a consequence and not the cause of resistance (Király et al, 1972), others have suggested that these changes directly mediate the action of fungicides and that therefore the plant participates as a component of fungicide effectiveness (Cartwright et al, 1977;Ward, 1984). In support of the latter hypothesis, some fungicides (e.g., fosetyl and copper) that are inactive in vitro against certain pathogen isolates can control them in the plant (Langcake and Wickins, 1975;Guest, 1984;Adaskaveg and Hine, 1985). (F test) showed that the synergistic and additive effects were significant (P Ͼ 0.95).…”

Section: Discussionmentioning

confidence: 99%

Impaired Fungicide Activity in Plants Blocked in Disease Resistance Signal Transduction

Molina¹,

Hunt²,

Ryals³

1998

The Plant Cell

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Fungicide action is generally assumed to be dependent on an antibiotic effect on a target pathogen, although a role for plant defense mechanisms as mediators of fungicide action has not been excluded. Here, we demonstrate that in Arabidopsis, the innate plant defense mechanism contributes to the effectiveness of fungicides. In NahG and nim1 (for noninducible immunity) Arabidopsis plants, which normally exhibit increased susceptibility to pathogens, the fungicides metalaxyl, fosetyl, and Cu(OH)2 are much less active and fail to control Peronospora parasitica. In contrast, the effectiveness of these fungicides is not altered in Arabidopsis mutants defective in the ethylene or jasmonic acid signal transduction pathways. Application of the systemic acquired resistance activator benzothiadiazole (BTH) in combination with these fungicides results in a synergistic effect on pathogen resistance in wild-type plants and an additive effect in NahG and BTH-unresponsive nim1 plants. Interestingly, BTH treatment normally induces long-lasting pathogen protection; however, in NahG plants, the protection is transient. These observations suggest that BTH treatment can compensate only partially for an impaired signal transduction pathway and support the idea that pathogen defense mechanisms are under positive feedback control. These observations are strikingly reminiscent of the reduced efficacy of antifungal agents in immunocompromised animals.

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“…Since the first conclusive demonstration that pre-inoculation of Xanthi-nc tobacco plants with tobacco mosaic virus (TMV) conferred enhanced protection against an array of viral pathogens (Ross, 1961), the concept of 'plant immunity' has expanded to include induced resistance against fungal pathogens causing major losses in field and greenhouse crop productions (Kú c, 1987;Uknes et al, 1992). The past few years have witnessed the discovery of a number of synthetic chemicals that act as strong elicitors of plant defense reactions, whilst being devoid of antimicrobial activity (Chen et al, 1993;Cohen et al, 1994;Langcake and Wickins, 1975;Mé traux et al, 1991). Probably the best studied of these compounds has been the 2,6-dichloroisonicotinic acid (INA, CGA 41396), identified by Ciba-Geigy as a potential inducer of systemic acquired resistance (SAR).…”

Section: Introductionmentioning

confidence: 99%

Induction of systemic resistance to Pythium damping‐off in cucumber plants by benzothiadiazole: ultrastructure and cytochemistry of the host response

1998

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SummaryBenzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH, CGA 245704), a non-toxic, synthetic chemical, was applied as a foliar spray to cucumber plants and evaluated for its potential to induce defense mechanisms in root tissues infected by the soilborne pathogen, Pythium ultimum Trow. In non-treated cucumber plants, fungal colonization was intense and paralleled marked host tissue damage, whereas in BTH-treated plants, pathogen ingress towards the vascular stele was apparently halted by the massive deposition of a phenolic-enriched material which occluded a large number of cortical and vascular parenchyma cells. This considerable increase in the accumulation of phenolics was accompanied by cytological disorders of the invading pathogen at a time when the wall-bound cellulose component was preserved. In addition to phenolic compounds, the occluding material contained large amounts of β-glucoside residues. These residues gradually decreased in the areas neighboring fungal cells whereas phenolic deposition appeared to be more uniformly distributed throughout the occluded host cells. Pathogen penetration in non-occluded cucumber root cells coincided with other changes, mainly characterized by both the deposition onto the inner surface of the cell walls of some heterogeneous wall appositions and the coating of some intercellular spaces with an electronopaque material. Evidence is provided in this study that BTH has the ability to induce SAR in cucumber. Exogenous, foliar applications of the chemical sensitize susceptible cucumber plants to react more rapidly and more efficiently to P. ultimum attack, mainly through the massive accumulation of phenolic compounds at sites of attempted pathogen penetration.

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Studies on the action of the dichlorocyclopropanes on the host-parasite relationship in the rice blast disease

Cited by 44 publications

References 29 publications

The tryptophan pathway is involved in the defense responses of rice against pathogenic infection via serotonin production

The tryptophan pathway is involved in the defense responses of rice against pathogenic infection via serotonin production

Impaired Fungicide Activity in Plants Blocked in Disease Resistance Signal Transduction

Induction of systemic resistance to Pythium damping‐off in cucumber plants by benzothiadiazole: ultrastructure and cytochemistry of the host response

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