A Novel Class of Elicitin-like Genes from <i>Phytophthora infestans</i>

Kamoun, Sophien; Lindqvist, Hannele; Govers, F.

doi:10.1094/mpmi.1997.10.8.1028

Cited by 78 publications

(77 citation statements)

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“…This suggests that the interaction of Nicotiana species with P. infestans follows the classic model of pathogen elicitor recognition by a plant receptor and the subsequent activation of signal transduction pathways leading to an HR. A candidate elicitor is the INF1 elicitin protein (Kamoun et al, 1997a), which induces an HR on all of the examined Nicotiana species but not on the host plants potato and tomato and which supposedly interacts specifically with a high-affinity binding site in the tobacco plasma membrane, as was shown for the P. cryptogea elicitin, cryptogein (Wendehenne et al, 1995).…”

Section: Discussionmentioning

confidence: 92%

“…Possibly, before recognition of INF1, tobacco responds to additional host-specific elicitors that are not detected by N. benthamiana. Putative candidates are the products of the inf2A and inf2B genes, both members of the P. infestans elicitin gene family (Kamoun et al, 1997a). These two genes are expressed in the plant during infection of potato and N. benthamiana, and their products induce an HR on tobacco (S. Kamoun, P. van West, and F. Govers, unpublished data).…”

Section: Discussionmentioning

confidence: 99%

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Resistance of Nicotiana benthamiana to Phytophthora infestans Is Mediated by the Recognition of the Elicitor Protein INF1

et al. 1998

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Phytophthora infestans , the agent of potato and tomato late blight disease, produces a 10-kD extracellular protein, INF1 elicitin. INF1 induces a hypersensitive response in a restricted number of plants, particularly those of the genus Nicotiana. In virulence assays with different P. infestans isolates, five Nicotiana species displayed resistance responses. In all of the interactions, after inoculation with P. infestans zoospores, penetration of an epidermal cell was observed, followed by localized necrosis typical of a hypersensitive response. To determine whether INF1 functions as an avirulence factor in these interactions, we adopted a gene-silencing strategy to inhibit INF1 production. Several transformants deficient in inf1 mRNA and INF1 protein were obtained. These strains remained pathogenic on host plants. However, in contrast to the wild-type and control transformant strains, INF1-deficient strains induced disease lesions when inoculated on N. benthamiana . These results demonstrate that the elicitin INF1 functions as an avirulence factor in the interaction between N. benthamiana and P. infestans . INTRODUCTIONMicrobial plant pathogens often exhibit high degrees of specialization and can only infect a limited number of plant species (Agrios, 1988). Pathogen specialization results when a complex set of preformed and induced mechanisms is put into motion to defend a plant against invading pathogens. In some interactions, preformed physical barriers and antimicrobial compounds in the plant help to ward off pathogens (Osbourn, 1996a(Osbourn, , 1996b. In other interactions, perception by the plant of signal molecules, namely, elicitors, produced by the avirulent pathogen leads to the induction of effective defense responses, including a programmed cell death response termed the hypersensitive response (HR) (Lamb et al., 1989; Dixon and Harrison, 1990; Ebel and Scheel, 1992; Baker et al., 1997;Morel and Dangl, 1997). This model has been genetically defined by Flor's gene-for-gene hypothesis (Flor, 1956(Flor, , 1971. According to this hypothesis, a resistance reaction is determined by the simultaneous expression of a pathogen avirulence ( Avr ) gene with the corresponding plant resistance ( R ) gene (Staskawicz et al., 1995).In recent years, the gene-for-gene hypothesis has received tremendous experimental support through the identification and functional characterization of both Avr and R genes. A number of Avr genes from fungi, bacteria, and viruses were shown to encode specific elicitor proteins. This was demonstrated directly by infiltration of Avr proteins into plant leaves or indirectly by expression of Avr genes in plant cells containing the corresponding R gene (Culver and Dawson, 1991; de Wit, 1995; Alfano and Collmer, 1996;Knogge, 1996; Bonas and van den Ackerveken, 1997; van den Ackerveken and Bonas, 1997). Elicitor treatment or Avr gene expression triggers the HR and related defense responses in plants that mimic the response induced by avirulent pathogens (Hahlbrock et al., 1995; Hammond-Kosa...

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Resistance of Nicotiana benthamiana to Phytophthora infestans Is Mediated by the Recognition of the Elicitor Protein INF1

et al. 1998

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“…In addition, an Agrobacterium strain carrying the PAMPinducing Inf1 (35S:Inf1; Kamoun et al, 1997) was also infiltrated. HR symptoms were visually scored at 4 DAI, and samples were taken at 5 DAI for quantification.…”

Section: Hr Assays In N Benthamianamentioning

confidence: 99%

Glycolate Oxidase Modulates Reactive Oxygen Species–Mediated Signal Transduction during Nonhost Resistance in Nicotiana benthamiana and Arabidopsis

et al. 2012

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In contrast to gene-for-gene disease resistance, nonhost resistance governs defense responses to a broad range of potential pathogen species. To identify specific genes involved in the signal transduction cascade associated with nonhost disease resistance, we used a virus-induced gene-silencing screen in Nicotiana benthamiana, and identified the peroxisomal enzyme glycolate oxidase (GOX) as an essential component of nonhost resistance. GOX-silenced N. benthamiana and Arabidopsis thaliana GOX T-DNA insertion mutants are compromised for nonhost resistance. Moreover, Arabidopsis gox mutants have lower H 2 O 2 accumulation, reduced callose deposition, and reduced electrolyte leakage upon inoculation with hypersensitive response-causing nonhost pathogens. Arabidopsis gox mutants were not affected in NADPH oxidase activity, and silencing of a gene encoding NADPH oxidase (Respiratory burst oxidase homolog) in the gox mutants did not further increase susceptibility to nonhost pathogens, suggesting that GOX functions independently from NADPH oxidase. In the two gox mutants examined (haox2 and gox3), the expression of several defense-related genes upon nonhost pathogen inoculation was decreased compared with wild-type plants. Here we show that GOX is an alternative source for the production of H 2 O 2 during both gene-for-gene and nonhost resistance responses.

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“…Molecular characterization of the crn genes suggests that they are widely distributed and form a complex gene family in Phytophthora similar to the ubiquitous INF elicitin family (Kamoun et al 1997;Kamoun 2000). However, the predicted CRN proteins are structurally unrelated to INF elicitins.…”

Section: Figurementioning

confidence: 99%

EST Mining and Functional Expression Assays Identify Extracellular Effector Proteins From the Plant PathogenPhytophthora

Torto

Li²,

Styer³

et al. 2003

Genome Res.

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Plant pathogenic microbes have the remarkable ability to manipulate biochemical, physiological, and morphological processes in their host plants. These manipulations are achieved through a diverse array of effector molecules that can either promote infection or trigger defense responses. We describe a general functional genomics approach aimed at identifying extracellular effector proteins from plant pathogenic microorganisms by combining data mining of expressed sequence tags (ESTs) with virus-based high-throughput functional expression assays in plants. PexFinder, an algorithm for automated identification of extracellular proteins from EST data sets, was developed and applied to 2147 ESTs from the oomycete plant pathogen Phytophthora infestans. The program identified 261 ESTs (12.2%) corresponding to a set of 142 nonredundant Pex (Phytophthora extracellular protein) cDNAs. Of these, 78 (55%) Pex cDNAs were novel with no significant matches in public databases. Validation of PexFinder was performed using proteomic analysis of secreted protein of P. infestans. To identify which of the Pex cDNAs encode effector proteins that manipulate plant processes, high-throughput functional expression assays in plants were performed on 63 of the identified cDNAs using an Agrobacterium tumefaciens binary vector carrying the potato virus X (PVX) genome. This led to the discovery of two novel necrosis-inducing cDNAs, crn1 and crn2, encoding extracellular proteins that belong to a large and complex protein family in Phytophthora. Further characterization of the crn genes indicated that they are both expressed in P. infestans during colonization of the host plant tomato and that crn2 induced defense-response genes in tomato. Our results indicate that combining data mining using PexFinder with PVX-based functional assays can facilitate the discovery of novel pathogen effector proteins. In principle, this strategy can be applied to a variety of eukaryotic plant pathogens, including oomycetes, fungi, and nematodes.

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A Novel Class of Elicitin-like Genes from Phytophthora infestans

Cited by 78 publications

References 15 publications

Resistance of Nicotiana benthamiana to Phytophthora infestans Is Mediated by the Recognition of the Elicitor Protein INF1

Resistance of Nicotiana benthamiana to Phytophthora infestans Is Mediated by the Recognition of the Elicitor Protein INF1

Glycolate Oxidase Modulates Reactive Oxygen Species–Mediated Signal Transduction during Nonhost Resistance in Nicotiana benthamiana and Arabidopsis

EST Mining and Functional Expression Assays Identify Extracellular Effector Proteins From the Plant PathogenPhytophthora

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