Molecular Basis of Gene-for-Gene Specificity in Bacterial Speck Disease of Tomato

Scofield, Steven R.; Tobias, Christian M.; Rathjen, John P.; Chang, Jeff H.; Lavelle, Daniel T.; Michelmore, Richard W.; Staskawicz, Brian J.

doi:10.1126/science.274.5295.2063

Cited by 484 publications

(338 citation statements)

References 16 publications

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“…Effector proteins secreted via type III secretion systems are thought to get translocated inside the target host cell where they are expected to stimulate or modulate host cellular functions (23,(30)(31)(32)(33)(34)(35)(36). We therefore investigated the translocation of AvrA into cultured intestinal Henle-407 cells infected with wild-type S. typhimurium using two complementary approaches.…”

Section: Resultsmentioning

confidence: 99%

A secreted Salmonella protein with homology to an avirulence determinant of plant pathogenic bacteria

Hardt

Galán

1997

Proc. Natl. Acad. Sci. U.S.A.

205

170

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Bacterial pathogens have evolved sophisticated mechanisms to interact with their hosts. A specialized type III protein secretion system capable of translocating bacterial proteins into host cells has emerged as a central factor in the interaction between a variety of mammalian and plant pathogenic bacteria with their hosts. Here we describe AvrA, a novel target of the centisome 63 type III protein secretion system of Salmonella enterica. AvrA shares sequence similarity with YopJ of the animal pathogen Yersinia pseudotuberculosis and AvrRxv of the plant pathogen Xanthomonas campestris pv. vesicatoria. These proteins are the first examples of putative targets of type III secretion systems in animal and plant pathogenic bacteria that share sequence similarity. They may therefore constitute a novel family of effector proteins with related functions in the cross-talk of these pathogens with their hosts.

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Section: Resultsmentioning

confidence: 99%

A secreted Salmonella protein with homology to an avirulence determinant of plant pathogenic bacteria

Hardt

Galán

1997

Proc. Natl. Acad. Sci. U.S.A.

205

170

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“…A ligand-receptor model has been postulated to explain the molecular basis of gene-for-gene interactions (Keen, 1990;Gabriel & Rolfe, 1990). Molecular characterization of matched pairs of plant R proteins and pathogen Avr proteins has provided support for this model in different plant-pathogen systems (Scofield et al, 1996;Tang et al, 1996;Jia et al, 2000). Another model, the so-called guard hypothesis (van der Biezen & Jones, 1998;Nimchuk et al, 2003), postulates an indirect interaction between the Avr and the R proteins, in which other host factor(s) might be involved (Dangl & Jones, 2001;Schulze-Lefert, 2004).…”

Section: Introductionmentioning

confidence: 99%

The coat protein of tobamovirus acts as elicitor of both L 2 and L 4 gene-mediated resistance in Capsicum

Gilardi¹,

García-Luque²,

Serra³

2004

Journal of General Virology

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In Capsicum, the resistance conferred by the L 2 gene is effective against all of the pepper-infecting tobamoviruses except Pepper mild mottle virus (PMMoV), whereas that conferred by the L 4 gene is effective against them all. These resistances are expressed by a hypersensitive response, manifested through the formation of necrotic local lesions (NLLs) at the primary site of infection. The Capsicum L 2 gene confers resistance to Paprika mild mottle virus (PaMMV), while the L 4 gene is effective against both PaMMV and PMMoV. The PaMMV and PMMoV coat proteins (CPs) were expressed in Capsicum frutescens (L 2 L 2 ) and Capsicum chacoense (L 4 L 4 ) plants using the heterologous Potato virus X (PVX)-based expression system. In C. frutescens (L 2 L 2 ) plants, the chimeric PVX virus containing the PaMMV CP was localized in the inoculated leaves and produced NLLs, whereas the chimeric PVX containing the PMMoV CP infected the plants systemically. Thus, the data indicated that the PaMMV CP is the only tobamovirus factor required for the induction of the host response mediated by the Capsicum L 2 resistance gene. In C. chacoense (L 4 L 4 ) plants, both chimeric viruses were localized to the inoculated leaves and produced NLLs, indicating that either PaMMV or PMMoV CPs are required to elicit the L 4 gene-mediated host response. In addition, transient expression of PaMMV CP into C. frutescens (L 2 L 2 ) leaves and PMMoV CP into C. chacoense (L 4 L 4 ) leaves by biolistic co-bombardment with a b-glucuronidase reporter gene led to the induction of cell death and the expression of host defence genes in both hosts. Thus, the tobamovirus CP is the elicitor of the Capsicum L 2 and L 4 gene-mediated hypersensitive response.

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“…The HR involves rapid, but localized, programmed plant cell death and is believed to restrict pathogen spread (1, 37). There is mounting evidence that the elicitation of an HR is mediated by the specific interaction between the products of a plant resistance gene (R gene) and a pathogen avirulence (avr) gene (43,80,85). It appears likely that at least some avr genes encode pathogenicity-related factors (34,47,71,84) that are transported into plant cells via the hrp-encoded transport machinery (58,59,90).…”

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confidence: 99%

Virulence of the Phytopathogen Pseudomonas syringae pv. Maculicola Is rpoN Dependent

et al. 2000

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We cloned the rpoN (ntrA and glnF) gene encoding 54 from the phytopathogen Pseudomonas syringae pv. maculicola strain ES4326. The P. syringae ES4326 rpoN gene complemented Pseudomonas aeruginosa, Escherichia coli, and Klebsiella aerogenes rpoN mutants for a variety of rpoN mutant phenotypes, including the inability to utilize nitrate as sole nitrogen source. DNA sequence analysis of the P. syringae ES4326 rpoN gene revealed that the deduced amino acid sequence was most similar (86% identity; 95% similarity) to the 54 protein encoded by the Pseudomonas putida rpoN gene. A marker exchange protocol was used to construct an ES4326 rpoN insertional mutation, rpoN::Km r . In contrast to wild-type ES4326, ES4326 rpoN::Km r was nonmotile and could not utilize nitrate, urea, C 4 -dicarboxylic acids, several amino acids, or concentrations of ammonia below 2 mM as nitrogen sources. rpoN was essential for production of the phytotoxin coronatine and for expression of the structural genes encoding coronamic acid. In addition, ES4326 rpoN::Km r did not multiply or elicit disease symptoms when infiltrated into Arabidopsis thaliana leaves, did not elicit the accumulation of several Arabidopsis defense-related mRNAs, and did not elicit a hypersensitive response (HR) when infiltrated into tobacco (Nicotiana tabacum) leaves. Furthermore, whereas P. syringae ES4326 carrying the avirulence gene avrRpt2 elicited an HR when infiltrated into Arabidopsis ecotype Columbia leaves, ES4326 rpoN::Km r carrying avrRpt2 elicited no response. Constitutive expression of ES4326 hrpL in ES4326 rpoN::Km r partially restored defense-related mRNA accumulation, showing a direct role for the hrp cluster in host defense gene induction in a compatible host-pathogen interaction. However, constitutive expression of hrpL in ES4326 rpoN::Km r did not restore coronatine production, showing that coronatine biosynthesis requires factors other than hrpL.The rpoN gene encodes the alternate sigma factor 54 , which works in conjunction with the NtrC class of transcriptional activators to control the expression of many genes in response to nutritional and environmental conditions (2, 54). For example, genes involved in nitrogen, hydrogen, and catabolite utilization are frequently regulated by 54 (6, 35, 48, 95). In the case of pathogenic bacteria, rpoN mediates expression of virulence-related factors such as pilin in Pseudomonas aeruginosa and flagellin in Vibrio anguillarum (24,61,86).For some phytopathogenic bacteria, rpoN has been implicated indirectly as a regulator of pathogenicity-related genes known as the hrp gene cluster (17, 18). Pseudomonas syringae pv. syringae strain 61, for example, contains a 25-kb hrp cluster consisting of several complementation groups comprising at least 27 genes (8, 26). Several hrp genes encode proteins that have a high degree of homology to components of the type III secretory pathway of Yersinia species which are responsible for translocating Yersinia outer membrane proteins into mammalian cells (13,15,55,83). By analogy, it is ...

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Molecular Basis of Gene-for-Gene Specificity in Bacterial Speck Disease of Tomato

Cited by 484 publications

References 16 publications

A secreted Salmonella protein with homology to an avirulence determinant of plant pathogenic bacteria

A secreted Salmonella protein with homology to an avirulence determinant of plant pathogenic bacteria

The coat protein of tobamovirus acts as elicitor of both L 2 and L 4 gene-mediated resistance in Capsicum

Virulence of the Phytopathogen Pseudomonas syringae pv. Maculicola Is rpoN Dependent

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