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ABSTRACT: Filamentous phytopathogens form sophisticated intracellular feeding structures called haustoria in plant cells. Pathogen effectors are likely to play a role in the establishment and maintenance of haustoria additional to their more characterized role of suppressing plant defense. Recent studies suggest that effectors may manipulate host transcription or other nuclear regulatory components for the benefit of pathogen development. However, the specific mechanisms by which these effectors promote susceptibility remain unclear. Of two recent screenings, we identified 15 nuclear-localized Hpa effectors (HaRxLs) that interact directly or indirectly with host nuclear components. When stably expressed in planta, nuclear HaRxLs cause diverse developmental phenotypes highlighting that nuclear effectors might interfere with fundamental plant regulatory mechanisms. Here, we report recent advances in understanding how a pathogen can manipulate nuclear processes in order to cause disease.
Cold Spring Harbor Symposia on Quantitative Biology 12/2012;
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ABSTRACT: The obligate biotrophic lineages of the white blister rusts (Albuginales, Oomycota) are of ancient origin compared to the rather recently evolved downy mildews, and sophisticated mechanisms of biotrophy and a high degree of adaptation diversity are to be expected in these organisms. Speciation in the biotrophic Oomycetes is usually thought to be the consequence of host adaptation or geographic isolation. Here we report the presence of two distinct species of Albugo on the model plant Arabidopsis thaliana, Albugo candida and Albugo laibachii, the latter being formally described in this manuscript. Both species may occupy the same host within the same environment, but are nevertheless phylogenetically distinct, as inferred from analyses of both mitochondrial and nuclear DNA sequences. Different ways of adapting to their host physiology might constitute an important factor of their different niches. Evidence for this can be gained from the completely different host range of the two pathogens. While Albugo candida is a generalist species, consisting of several physiological varieties, which is able to parasitize a great variety of Brassicaceae, Albugo laibachii has not been found on any host other than Arabidopsis thaliana. Therefore, Albugo laibachii belongs to a group of highly specialised species, like the other known specialist species in Albugo s.s., Albugo koreana, Albugo lepidii and Albugo voglmayrii. The comparative investigation of the effector genes and host targets in the generalist and the specialist species may constitute a model system for elucidating the fundamental processes involved in plant pathogen co-adaptation and speciation.
Persoonia - Molecular Phylogeny and Evolution of Fungi 06/2009; 22:123-8. · 4.14 Impact Factor
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J.D.G. Jones,
S. Rivas,
A. Heese-Peck,
O. Rowland,
A. Rujon,
A. Ludwig,
A. Sadanandom,
R. Gonzalez-Lamothe,
Burg,
H.A,
van den,
L. Fritz-Laylin,
L. Navarro,
K. Sjolander,
M. Tor,
E. Holub,
Wit,
P.J.G.M
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7th International Congress of Plant Pathology, Edinburgh, UK (1998).
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ABSTRACT: How plants recognize pathogens and activate defense is still mysterious. Direct interaction between pathogen avirulence (Avr) proteins and plant disease resistance proteins is the exception rather than the rule. During infection, Cladosporium fulvum secretes Avr2 protein into the apoplast of tomato leaves and, in the presence of the extracellular leucine-rich repeat receptor-like Cf-2 protein, triggers a hypersensitive response (HR) that also requires the extracellular tomato cysteine protease Rcr3. We show here that Avr2 binds and inhibits Rcr3 and propose that the Rcr3-Avr2 complex enables the Cf-2 protein to activate an HR
Science 308 (2005) 5729.
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V. Nekrasov,
J. Li,
M. Roux,
M. Batoux,
S. Lacombe,
A. Rougon,
Z. Chu,
M. Kisspapp,
D. Chinchilla,
Esse,
H.P,
L. Jorda,
B. Schwessinger,
V. Nicaise,
B.P.H.J. Thomma,
A Molina, J.D.G. Jones,
C. Zipfel
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Tomato Genet. Coop. Report 46 (1996) 9-10.
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The Plant Journal 35 (2003).
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Plant Cell 11 (1999) 11.
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Plant Journal 20 (1999) 3.
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ABSTRACT: In the past, numerous Cf genes have been reported in tomato (Lycopersicon esculentum Mill.) that confer resistance against leaf mould (Cladosporium fulvum Cke.). We are interested in genetic variation at Cf loci. Therefore, previously uncharacterized Cf genes were further analysed. Recognition of the AVR4 elicitor, DNA gel blot analysis, PCR analysis and sequencing of part of the Cf-4 locus showed that a large proportion of the accessions tested harboured the Cf-4 resistance gene. We concluded that despite differences in nomenclature, all these accessions harbour the same Cf-4 locus, probably introgressed from the same donor. The origin of the Cf-4 locus and the reasons for discrepancies with earlier reports are discussed
Heredity 85 (2000).
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Wit,
P.J.G.M,
B.F. Brandwagt,
M.D. Bolton,
Burg,
H.A,
van den,
Esse,
H.P,
E.F. Fradin, [......],
Kock,
M.J.D,
M. Kruijt,
P. Lindhout,
H.C.E. Rooney,
I. Stergiopoulos,
I.J.E. Stulemeijer,
J.J.M. Vervoort,
J.H. Vossen,
B.P.H.J. Thomma
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Abstract 8th Int. Congr. on Molecular Plant-Microbe Interactions, Knoxville, USA (1996) X-31.
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G. Fabro, J.D.G. Jones,
M. Coates,
L Baxter,
J. Steinbrenner,
J Beynon,
S. Katou,
J. Bautor,
J. Parker,
A. Cabral,
A.F.J.M. van den Ackerveken
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Guodong Wang,
U. Ellendorff,
B. Kemp,
J.W. Mansfield,
A. Forsyth,
K. Mitchell,
K. Bastas,
C.M. Liu,
A. Woods-Tör,
C. Zipfel,
Wit,
P.J.G.M, J.D.G. Jones,
M. Tör,
B.P.H.J. Thomma
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ABSTRACT: Receptor-like proteins (RLPs) are cell surface receptors that typically consist of an extracellular leucine-rich repeat domain, a transmembrane domain, and a short cytoplasmatic tail. In several plant species, RLPs have been found to play a role in disease resistance, such as the tomato (Solanum lycopersicum) Cf and Ve proteins and the apple (Malus domestica) HcrVf2 protein that mediate resistance against the fungal pathogens Cladosporium fulvum, Verticillium spp., and Venturia inaequalis, respectively. In addition, RLPs play a role in plant development; Arabidopsis (Arabidopsis thaliana) TOO MANY MOUTHS (TMM) regulates stomatal distribution, while Arabidopsis CLAVATA2 (CLV2) and its functional maize (Zea mays) ortholog FASCINATED EAR2 regulate meristem maintenance. In total, 57 RLP genes have been identified in the Arabidopsis genome and a genome-wide collection of T-DNA insertion lines was assembled. This collection was functionally analyzed with respect to plant growth and development and sensitivity to various stress responses, including susceptibility toward pathogens. A number of novel developmental phenotypes were revealed for our CLV2 and TMM insertion mutants. In addition, one AtRLP gene was found to mediate abscisic acid sensitivity and another AtRLP gene was found to influence nonhost resistance toward Pseudomonas syringae pv phaseolicola. This genome-wide collection of Arabidopsis RLP gene T-DNA insertion mutants provides a tool for future investigations into the biological roles of RLPs
Plant Physiology 147 (2008).
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ABSTRACT: The tomato (Lycopersicon pimpinellifolium) resistance protein Cf-9 belongs to a large class of plant proteins with extracytoplasmic Leu-rich repeats (eLRRs). eLRR proteins play key roles in plant defense and development, mainly as receptor-like proteins or receptor-like kinases, conferring recognition of various pathogen molecules and plant hormones. We report here a large-scale structure¿function analysis of an eLRR protein. A total of 66 site-directed mutants of Cf-9 were analyzed for activity in Avr9 recognition and for protein stability and the results interpreted with the help of a homology model of the Cf-9 structure. Conserved Trp and Cys pairs in the N-terminal LRR-flanking domain appear to be important for Cf-9 activity and are probably exposed at the putative concave inner surface of the Cf-9 protein, where recognition specificity also resides. Removal of each of the 22 putative N-linked glycosylation sites (PGS) revealed that many PGSs contribute to Cf-9 activity and that the PGSs in the putative -helices of the LRR modules are essential. Immunoblot analysis and mass spectrometry showed that all but one of the PGSs are N-glycosylated. Introduction of glycosylation at the putative concave ß-sheet surface blocks Cf-9 activity, in some cases probably by disturbing specific recognition, and in another case by steric hindrance with existing N-glycans. The glycosylation pattern and several other features are conserved in other eLRR proteins, where similar mutations show similar phenotypes.
The Plant Cell 17 (2005) 3.
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ABSTRACT: Tomato Cf genes encode membrane-bound proteins with extracellular leucine-rich repeats, and confer resistance to the fungal tomato pathogen Cladosporium fulvum, and a hypersensitive response (HR) to C. fulvum-derived race-specific elicitors. Several Cf genes, including Cf-4 and Cf-9, are members of the highly homologous Hcr9 (homologues of C. fulvumresistance gene Cf-9) gene family. Hcr9s evolve mainly by sequence exchange between paralogues, by which novel Cf genes may be generated. To mimic this aspect of natural evolution, we generated chimeras between multiple Hcr9s in vitro by gene shuffling. The shufflants were tested for novel specificities by transient expression in Nicotiana benthamiana. Many shufflants induced an HR in the absence of fungal elicitors and were designated auto-activators. We also identified two natural Hcr9 auto-activators in the wild tomato species Lycopersicon peruvianum, which induced an HR upon expression in N. benthamiana. The Hcr9 auto-activators exhibit different auto-necrosis-inducing specificities in five selected species of the Nicotiana genus, and they were shown to function in the same signalling pathway as Cf-9. Auto-activating alleles of nucleotide binding siteleucine-rich repeat genes and the protein kinase Pto were previously described. The auto-activators described here, belonging to the Cf-like structural class of resistance genes, shed light on this important phenotype and may be used as tools to unravel the mechanisms by which this class of resistance proteins function.
The Plant Journal 40 (2004) 6.
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ABSTRACT: The diverse roles of plant proteases in defence responses that are triggered by pathogens or pests are becoming clearer. Some proteases, such as papain in latex, execute the attack on the invading organism. Other proteases seem to be part of a signalling cascade, as indicated by protease inhibitor studies. Such a role has also been suggested for the recently discovered metacaspases and CDR1. Some proteases, such as RCR3, even act in perceiving the invader. These exciting recent reports are probably just the first examples of what lies beneath. More roles for plant proteases in defence, as well as the regulation and substrates of these enzymes, are waiting to be discovered. AEBSF, p-aminoethylbenzenesulphonyl fluoride; Avr, avirulence gene; CDR1, CONSTITUTIVE DISEASE RESISTANCE-1; E-64d, trans-epoxysuccinyl-leucylamido-3-methylbutane ester; ER, endoplasmic reticulum; HR, hypersensitive response; LapA, acidic leucine aminopeptidase; MCP, metacaspase; Mir1, maize inbred resistant-1; NO, nitric oxide; P69, 69-kDa PR protein; PCD, programmed cell death; PR, pathogenesis-related; RCR3, REQUIRED FOR Cladosporium RESISTANCE-3; RD21, RESPONSIVE TO DESICCATION-21; TMV, tobacco mosaic virus; VPE, vacuolar processing enzyme; YCA1, yeast caspase-1
Current Opinion in Plant Biology 7 (2004) 4.
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R. Luderer,
S. Rivas,
T. Nurnberger,
B Mattei,
Hooven,
H.W,
van den,
Hoorn,
R.A.L,
T Romeis,
J.M. Wehrfritz,
B Blume,
D Nennstiel,
D. Zuidema,
J.J.M. Vervoort,
Lorenzo, J.D.G. Jones,
Wit,
P.J.G.M,
M.H.A.J. Joosten
[show abstract]
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ABSTRACT: The gene-for-gene model postulates that for every gene determining resistance in the host plant, there is a corresponding gene conditioning avirulence in the pathogen. On the basis of this relationship, products of resistance (R) genes and matching avirulence (Avr) genes are predicted to interact. Here, we report on binding studies between the R gene product Cf-9 of tomato and the Avr gene product AVR9 of the pathogenic fungus Cladosporium fulvum. Because a high-affinity binding site (HABS) for AVR9 is present in tomato lines, with or without the Cf-9 resistance gene, as well as in other solanaceous plants, the Cf-9 protein was produced in COS and insect cells in order to perform binding studies in the absence of the HABS. Binding studies with radio-labeled AVR9 were performed with Cf-9-producing COS and insect cells and with membrane preparations of such cells. Furthermore, the Cf-9 gene was introduced in tobacco, which is known to be able to produce a functional Cf-9 protein. Binding of AVR9 to Cf-9 protein produced in tobacco was studied employing surface plasmon resonance and surface-enhanced laser desorption and ionization. Specific binding between Cf-9 and AVR9 was not detected with any of the procedures. The implications of this observation are discussed.
Molecular Plant-Microbe Interactions 14 (2001) 7. - ISSN 0894-0282.
