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Cold Spring Harbor Symposium on Quantitative Biology: Effector Biology of Plant-Associated Organisms: Concepts and Perspectives (2012)

Cold Spring Harbor Symposium on Quantitative Biology: Effector Biology of Plant-Associated Organisms: Concepts and Perspectives (2012) | Effectors and Plant Immunity | Scoop.it

Every plant is closely associated with a variety of living organisms. Therefore, deciphering howplants interact with mutualistic and parasitic organisms is essential for a comprehensive understanding of the biology of plants. The field of plant–biotic interactions has recently coalesced around an integrated model. Major classes of molecular players both from plants and their associated organisms have been revealed. These include cell surface and intracellular immune receptors of plants, as well as apoplastic and host-cell translocated (cytoplasmic) effectors of the invading organism. This article focuses on effectors, molecules secreted by plant-associated organisms that alter plant processes. Effectors have emerged as a central class of molecules in our integrated view of plant–microbe interactions. Their study has significantly contributed to advancing our knowledge of plant hormones, plant development, plant receptors, and epigenetics. Many pathogen effectors are extraordinary examples of biological innovation; they include some of themost remarkable proteins knownto function inside plant cells. Here, we review some of the key concepts that have emerged from the study of the effectors of plant-associated organisms. In particular, we focus on how effectors function in plant tissues and discuss future perspectives in the field of effector biology.

 

http://kamounlab.dreamhosters.com/pdfs/CSHSQB_2012.pdf


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Storify: #MPMI2014 Day 5 of XVI IC-MPMI, Rhodes, Greece, 6-10 July


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Storify: #MPMI2014 Day 3 of XVI IC-MPMI, Rhodes, Greece, 6-10 July


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Jean-Michel Ané's curator insight, July 9, 8:27 AM

I am so disappointed to miss this conference...

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Curr. Op. Plant Biol.: Principles and applications of TAL effectors for plant physiology and metabolism (2014)

Recent advances in DNA targeting allow unprecedented control over gene function and expression. Targeting based on TAL effectors is arguably the most promising for systems biology and metabolic engineering. Multiple, orthogonal TAL-effector reagents of different types can be used in the same cell. Furthermore, variation in base preferences of the individual structural repeats that make up the TAL effector DNA recognition domain makes targeting stringency tunable. Realized applications range from genome editing to epigenome modification to targeted gene regulation to chromatin labeling and capture. The principles that govern TAL effector DNA recognition make TAL effectors well suited for applications relevant to plant physiology and metabolism. TAL effector targeting has merits that are distinct from those of the RNA-based DNA targeting CRISPR/Cas9 system.

 

Adam J Bogdanove

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New Phytol.: Engaging students with plant science: the Plant Science TREE (2014)

New Phytol.: Engaging students with plant science: the Plant Science TREE (2014) | Effectors and Plant Immunity | Scoop.it

In this paper, we show how a single web resource can engage a wide student audience with plant science. Developed by the University of Leeds, UK, the Plant Science TREE (Tool for Research Engaged Education (www.tree.leeds.ac.uk)) is an online teaching tool giving access to online research lectures, downloadable lecture slides, practicals, movies and other material on topical plant science to support lecturers in their teaching. The Plant Science TREE complements the annual Gatsby Plant Science Summer School, which has already succeeded in engaging undergraduates with plant science (Levesley et al., 2012). Both initiatives were instigated to address the decline in student numbers in plant science (Sundberg, 2004; Stagg et al., 2009; Jones, 2010; Drea, 2011) at a time when there is concern that future demand for plant scientists will not be met (The Royal Society, 2009). The causes of this decline are unproven but may be the result of a combination of factors including, greater preference by students for animal and medically-based degrees, disengagement from plant science at school, and narrowing of plant-based undergraduate curricula. Where the summer school aims, by face-to-face contact, to inspire relatively small numbers of high-achieving students to consider plant science as a career option, the Plant Science TREE aims to reach a much larger, more diverse global audience through the use of web technologies.

 

Aurora Levesley, Steve Paxton, Richard Collins, Alison Baker and Celia Knight

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A reference genome for common bean and genome-wide analysis of dual domestications : Nature Genetics : Nature Publishing Group

A reference genome for common bean and genome-wide analysis of dual domestications : Nature Genetics : Nature Publishing Group | Effectors and Plant Immunity | Scoop.it
Scott Jackson, Jeremy Schmutz, Phillip McClean and colleagues report the genome sequence of the common bean (Phaseolus vulgaris) and resequenced wild individuals and landraces from Mesoamerican and Andean gene pools, showing that common bean underwent two independent domestications.

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Mary Williams's curator insight, June 10, 4:59 AM

Quite an intersting study on the origin of Phaseolus vulgaris based on genome sequences. You can see one of the lead authors talking about this work at this link

http://phys.org/news/2014-06-hill-beans-phaseolus-genome-insights.html

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Front. Plant Sci.: Analysis of plant microbe interactions in the era of next generation sequencing technologies (2014)

Front. Plant Sci.: Analysis of plant microbe interactions in the era of next generation sequencing technologies (2014) | Effectors and Plant Immunity | Scoop.it

Next generation sequencing (NGS) technologies have impressively accelerated research in biological science during the last years by enabling the production of large volumes of sequence data to a drastically lower price per base, compared to traditional sequencing methods. The recent and ongoing developments in the field allow addressing research questions in plant-microbe biology that were not conceivable just a few years ago. The present review provides an overview of NGS technologies and their usefulness for the analysis of microorganisms that live in association with plants. Possible limitations of the different sequencing systems, in particular sources of errors and bias, are critically discussed and methods are disclosed that help to overcome these shortcomings. A focus will be on the application of NGS methods in metagenomic studies, including the analysis of microbial communities by amplicon sequencing, which can be considered as a targeted metagenomic approach. Different applications of NGS technologies are exemplified by selected research articles that address the biology of the plant associated microbiota to demonstrate the worth of the new methods.

 

Claudia Knief

 

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MPMI: P. syringae CC1557: a highly virulent strain with an unusually small type III effector repertoire that includes a novel effector (2014)

MPMI: P. syringae CC1557: a highly virulent strain with an unusually small type III effector repertoire that includes a novel effector (2014) | Effectors and Plant Immunity | Scoop.it

Both type III effector proteins and non-ribosomal peptide toxins play important roles for Pseudomonas syringae pathogenicity in host plants, but whether and how these pathways interact to promote infection remains unclear. Genomic evidence from one clade of P. syringae suggests a tradeoff between the total number of type III effector proteins and presence of syringomycin, syringopeptin, and syringolin A toxins. Here we report the complete genome sequence from P. syringae CC1557, which contains the lowest number of known type III effectors to date and has also acquired genes similar to sequences encoding syringomycin pathways from other strains. We demonstrate that this strain is pathogenic on Nicotiana benthamiana and that both the type III secretion system and a new type III effector family, hopBJ1, contribute to pathogenicity. We further demonstrate that activity of HopBJ1 is dependent on residues structurally similar to the catalytic site of E. coli CNF1 toxin. Taken together, our results provide additional support for a negative correlation between type III effector repertoires and the potential to produce syringomycin-like toxins while also highlighting how genomic synteny and bioinformatics can be used to identify and characterize novel virulence proteins.


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Repeat 1 of TAL effectors affects target specificity for the base at position zero - Nucl. Acids Res.

Repeat 1 of TAL effectors affects target specificity for the base at position zero - Nucl. Acids Res. | Effectors and Plant Immunity | Scoop.it

Schreiber & Bonas 2014

AvrBs3, the founding member of the Xanthomonas transcription-activator-like effectors (TALEs), is translocated into the plant cell where it localizes to the nucleus and acts as transcription factor. The DNA-binding domain of AvrBs3 consists of 17.5 nearly-identical 34 amino acid-repeats. Each repeat specifies binding to one base in the target DNA via amino acid residues 12 and 13 termed repeat variable diresidue (RVD). Natural target sequences of TALEs are generally preceded by a thymine (T0), which is coordinated by a tryptophan residue (W232) in a degenerated repeat upstream of the canonical repeats. To investigate the necessity of T0 and the conserved tryptophan for AvrBs3-mediated gene activation we tested TALE mutant derivatives on target sequences preceded by all possible four bases. In addition, we performed domain swaps with TalC from a rice pathogenic Xanthomonas because TalC lacks the tryptophan residue, and the TalC target sequence is preceded by cytosine. We show that T0 works best and that T0 specificity depends on the repeat number and overall RVD-composition. T0 and W232 appear to be particularly important if the RVD of the first repeat is HD (‘rep1 effect’). Our findings provide novel insights into the mechanism of T0 recognition by TALE proteins and are important for TALE-based biotechnological applications.


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Science: Paired Plant Immune Receptors (2014)

Science: Paired Plant Immune Receptors (2014) | Effectors and Plant Immunity | Scoop.it

Plants are constantly interpreting microbial signals from potential pathogens and potential commensals or mutualists. Because plants have no circulating cells dedicated to this task, every plant cell must, in principle, recognize any microbe as friend, foe, or irrelevant bystander. That tall order is mediated by an array of innate immune system receptors: pattern-recognition receptors outside the plant cell and nucleotide-binding oligomerization domain (NOD)–like receptors (NLRs) inside the cell. Despite their importance for plant health, how NLRs function mechanistically has remained obscure. On page 299 of this issue, Williams et al. (1) reveal a role for heterodimerization between NLRs and show how the rather limited NLR repertoire of any plant genome might be enhanced by combinatorial diversity.

 

Marc T. Nishimura, Jeffery L. Dangl

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PLoS ONE: Real Time Live Imaging of Phytopathogenic Bacteria Xanthomonas campestris pv. campestris MAFF106712 in ‘Plant Sweet Home’ (2014)

PLoS ONE: Real Time Live Imaging of Phytopathogenic Bacteria Xanthomonas campestris pv. campestris MAFF106712 in ‘Plant Sweet Home’ (2014) | Effectors and Plant Immunity | Scoop.it

Xanthomonas is one of the most widespread phytobacteria, causing diseases on a variety of agricultural plants. To develop novel control techniques, knowledge of bacterial behavior inside plant cells is essential. Xanthomonas campestris pv. campestris, a vascular pathogen, is the causal agent of black rot on leaves of Brassicaceae, including Arabidopsis thaliana. Among the X. campestris pv. campestris stocks in the MAFF collection, we selected XccMAFF106712 as a model compatible pathogen for the A. thaliana reference ecotype Columbia (Col-0). Using modified green fluorescent protein (AcGFP) as a reporter, we observed real time XccMAFF106712 colonization in planta with confocal microscopy. AcGFP-expressing bacteria colonized the inside of epidermal cells and the apoplast, as well as the xylem vessels of the vasculature. In the case of the type III mutant, bacteria colonization was never detected in the xylem vessel or apoplast, though they freely enter the xylem vessel through the wound. After 9 days post inoculation with XccMAFF106712, the xylem vessel became filled with bacterial aggregates. This suggests that Xcc colonization can be divided into main four steps, (1) movement in the xylem vessel, (2) movement to the next cell, (3) adhesion to the host plant cells, and (4) formation of bacterial aggregates. The type III mutant abolished at least steps (1) and (2). Better understanding of Xcc colonization is essential for development of novel control techniques for black rot.

 

Chiharu Akimoto-Tomiyama,  Ayako Furutani,  Hirokazu Ochiai

 

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Freddy Monteiro's comment, April 17, 9:21 AM
"Real-time imaging of showing release of bacteria from the xylem vessel is shown in Movies S8, S9. The bacteria seemed to be aggregated inside the xylem vessel 9 days post inoculation (Figures 7B, S2, Movie S9), with the size of the aggregates depending on each xylem vessel. Notably, the size of the aggregates within a single xylem vessel was relatively consistent. In contrast, bacteria from a xylem vessel only 6 days post inoculation (Figure 7A, Movie S8) seemed not to make such bacterial aggregates, but rather to remain as single cells. The size of bacterial aggregates was measured as pixels of the area showing AcGFP fluorescence, demonstrating the size of the aggregates dramatically increases between 6 and 9 days (Figure 7C). We also noted that the released bacterial aggregates did not move, while single bacteria moved vigorously (Movie S10). At 6 days post inoculation, the infected site in the xylem vessel appeared transversely extended (Movie S4) and most of the bacteria did not move (Movie S3). From these observations, we conclude that active single bacteria with high motility move freely inside the xylem vessel, and upon finding a suitable niche (such as one with a low abundance of other bacteria), they adhere to the plant cells and starts multiplying"
Freddy Monteiro's comment, April 17, 9:24 AM
I find that excerpt very interesting. A similar discussion was held in my PhD defense regarding R.solanacearum infection. This is a nice piece of work =)
Suayib Üstün's comment, April 18, 8:17 AM
interesting, however citation 46 is wrong. should be üstün et al., 2013. ;-)
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PLANT SCIENCE SUMMER SCHOOL ANGERS 1st Edition - 30th June – 12th July 2014 Faculty of sciences, University of Angers

PLANT SCIENCE SUMMER SCHOOL ANGERS 1st Edition -  30th June – 12th July 2014 Faculty of sciences, University of Angers | Effectors and Plant Immunity | Scoop.it

 

This program will provide the students with some insights into
new developments in plant science research. The purpose is to
give students the opportunity to be exposed to multidisciplinary
approaches in the field of sustainable management of plant
health and quality.

 

Workshops:
Visits of international research institutes
– GEVES lab (the French Group for the Study and Inspection of Varieties and Seeds)
– LSV-ANSES (Plant Health Laboratory)
– CIRM-CFBP (French Collection of Bacteria associated to Plants)
– ANAN (Nucleic acid analysis) Platform
– ITEPMAI (Institute for medicinal and aromatic plants)
– Visits of a botanical garden, a rose garden, and an organic vineyard

 

The program relies on interactive classes and hands-on ativities. Several workshops are organized, among them

"Experiments in chemical ecology and pest management"
"In Silico design of plant pathogen identification tests"
"Field observations of Black spot disease on rose genotypes"
"Extraction-identification and biological activity testing of plant polyphenols"
"Macroscopic and microscopic observations of medicinal plants"
"Rose phenotyping and genotyping"
"Analytical methods for assessing fruit quality"

 

Sessions:
Plenary conference by Prof Jean Weissenbach
Session 1: Chemical ecology and Pest management
Session 2: Genomic and Bacterial diagnostic
Session 3: Fungal foliar disease on ornamentals
Session 4: Weed control in intercropping systems
Session 5: Metabolomics and medicinal plants
Session 6: Ornamentals Interaction genotype X environment
Session 7: Fruit production, Fruit development and self-thinning
Session 8: Fruit production and quality

 

Invited speakers:
– J. Weissenbach
– P. Anderson, Alnarp, Sweden
– M M. López, Valencia, Spain
– T. Debener, Hannover, Germany
– JL. Wolfender, Genève, Switzerland
– MC. van Labeke, Gent, Belgium
– Al. Botton, Padova, Italy

 

Criteria:
The program is open to undergraduate students in the fields of agriculture, plant science and biological science who may be interested in pursuing Ph.D. programs and envision a career in plant science/agriculture.

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The Pepper SGT1 Interacts with the Receptor-Like Cytoplasmic Kinase 1 and AvrBsT and Promotes Hypersensitive Cell Death Response in a Phosphorylation-Dependent Manner

The Pepper SGT1 Interacts with the Receptor-Like Cytoplasmic Kinase 1 and AvrBsT and Promotes Hypersensitive Cell Death Response in a Phosphorylation-Dependent Manner | Effectors and Plant Immunity | Scoop.it

Xanthomonas campestris pv. vesicatoria type III effector protein, AvrBsT, triggers hypersensitive cell death in pepper (Capsicum annuum). Here, we have identified the pepper SGT1 (suppressor of the G2 allele of skp1) as a host interactor of AvrBsT and also the pepper PIK1 (receptor-like cytoplasmic kinase 1). PIK1 specifically phosphorylates SGT1 and AvrBsT in vitro. AvrBsT specifically binds to the CS domain of SGT1, resulting in the inhibition of PIK1-mediated SGT1 phosphorylation and subsequent nuclear transport of the SGT1-PIK1 complex. Liquid chromatography-tandom mass spectrometry (LC/MS/MS) of the proteolytic peptides of SGT1 identified the residues Serine 98 and Serine 279 of SGT1 as the major PIK1-mediated phosphorylation sites. Site directed mutagenesis of SGT1 revealed that the identified SGT1 phosphorylation sites are responsible for the activation of AvrBsT-triggered cell death in planta. SGT1 forms a heterotrimeric complex with both AvrBsT and PIK1 exclusively in the cytoplasm. Agrobacterium-mediated co-expression of SGT1 and PIK1 with avrBsT promotes avrBsT-triggered cell death in Nicotiana benthamiana, dependent on PIK1. Virus-induced silencing of SGT1 and/or PIK1 compromises avrBsT-triggered cell death, H2O2 production, defense gene induction and salicylic acid accumulation, leading to the enhanced bacterial pathogen growth in pepper. Together, these results suggest that SGT1 interacts with PIK1 and bacterial effector protein AvrBsT and promotes hypersensitive cell death associated with PIK1-mediated phosphorylation in plants.


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Science: A Bacterial Tyrosine Phosphatase Inhibits Plant Pattern Recognition Receptor Activation (2014)

Science: A Bacterial Tyrosine Phosphatase Inhibits Plant Pattern Recognition Receptor Activation (2014) | Effectors and Plant Immunity | Scoop.it

Innate immunity relies on the perception of pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptors (PRRs) located on the host cell’s surface. Many plant PRRs are kinases. Here, we report that the Arabidopsis receptor kinase EF-TU RECEPTOR EFR, which perceives the elf18 peptide derived from bacterial elongation factor Tu, is activated upon ligand binding by phosphorylation on its tyrosine residues. Phosphorylation of a single tyrosine residue, Y836, is required for activation of EFR and downstream immunity to the phytopathogenic bacterium Pseudomonas syringae. A tyrosine phosphatase, HopAO1, secreted by P. syringae, reduces EFR phosphorylation and derails subsequent immune responses. Thus host and pathogen battle to take control of PRR tyrosine phosphorylation used to initiate anti-bacterial immunity.

 

Alberto P. Macho, Benjamin Schwessinger, Vardis Ntoukakis, Alexandre Brutus, Cécile Segonzac, Sonali Roy, Yasuhiro Kadota, Man-Ho Oh, Jan Sklenar, Paul Derbyshire, Rosa Lozano-Durán, Frederikke Gro Malinovsky, Jacqueline Monaghan, Frank L. Menke, Steven C. Huber, Sheng Yang He, Cyril Zipfel

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Storify: #MPMI2014 Day 4 of XVI IC-MPMI, Rhodes, Greece, 6-10 July


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Storify Tweet Archive of #MPMI2014 Days 1 and 2 of XVI IC-MPMI, Rhodes, Greece, 6-10 July


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Découverte d’une stratégie commune de dégradation de composés végétaux chez les bactéries phytopathogènes et intestinales

Découverte d’une stratégie commune de dégradation de composés végétaux chez les bactéries phytopathogènes et intestinales | Effectors and Plant Immunity | Scoop.it

Les chercheurs du Laboratoire des Interactions Plantes-Microorganismes (LIPM) du centre INRA de Toulouse ont déterminé comment le xylane, un composé majeur de la paroi cellulaire végétale, était décomposé par la bactérie phytopathogène Xanthomonas campestris pv campestris (Xcc). Leurs résultats ont mis en évidence que cette dégradation dépendait d’un système spécifique composé de transporteurs et d’enzymes. Plus intéressant encore, ce même système de dégradation est utilisé par les bactéries symbiotiques de l’intestin humain ! Cette découverte a fait l’objet d’une publication dans la revue scientifique New Phytologist. (Déjean et al. 2013, 198(3):899-915).

 

 

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Curr. Op. Plant Biol.: Special issue on biotic interactions (2014)

From local to global: CDPKs in systemic defense signaling upon microbial and herbivore attack

    Tina Romeis, Marco Herde

 

Actinorhizal root nodule symbioses: what is signalling telling on the origins of nodulation?

    Sergio Svistoonoff, Valérie Hocher, Hassen Gherbi

 

Inside plant: biotrophic strategies to modulate host immunity and metabolism

    Bilal Ökmen, Gunther Doehlemann

 

Phytohormone signaling in arbuscular mycorhiza development

    Caroline Gutjahr

 

Transcriptional control of plant defence responses

    Pierre Buscaill, Susana Rivas

 

Immune receptor complexes at the plant cell surface

    Hannah Böhm, Isabell Albert, Li Fan, André Reinhard, Thorsten Nürnberger

 

Structural insight into the activation of plant receptor kinases

    Zhifu Han, Yadong Sun, Jijie Chai

 

Perception of the plant immune signal salicylic acid

    Shunping Yan, Xinnian Dong

 

The changing of the guard: the Pto/Prf receptor complex of tomato and pathogen recognition

    Vardis Ntoukakis, Isabel ML Saur, Brendon Conlan, John P Rathjen

 

Microbe–microbe interactions determine oomycete and fungal host colonization

    Eric Kemen

 

Extracellular ATP is a central signaling molecule in plant stress responses

    Yangrong Cao, Kiwamu Tanaka, Cuong T Nguyen, Gary Stacey

 

Interaction between viral RNA silencing suppressors and host factors in plant immunity

    Kenji S Nakahara, Chikara Masuta

 

Filamentous pathogen effector functions: of pathogens, hosts and microbiomes

    Hanna Rovenich, Jordi C Boshoven, Bart PHJ Thomma

 

Staying in touch: mechanical signals in plant–microbe interactions

    Dhileepkumar Jayaraman, Simon Gilroy, Jean-Michel Ané

 

Opening the Ralstonia solanacearum type III effector tool box: insights into host cell subversion mechanisms

    Laurent Deslandes, Stephane Genin

 

Cross-interference of plant development and plant–microbe interactions

    Edouard Evangelisti, Thomas Rey, Sebastian Schornack

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New Phytol.: ZRK atypical kinases: emerging signaling components of plant immunity (2014)

New Phytol.: ZRK atypical kinases: emerging signaling components of plant immunity (2014) | Effectors and Plant Immunity | Scoop.it

Plants sense invasion of potential microbial pathogens using various receptors and launch cascades of innate immune responses that are critical for survival and fecundity. Recognition of pathogens occurs through detection of pathogen-associated patterns (PAMPs) or pathogen effectors, setting off a cascade of signaling events that triggers early cellular and molecular responses. Plant innate immunity is constituted by an elaborate, multilayered system involving two intertwined lines of defense: a first level of immunity termed PAMP–triggered immunity (PTI) or basal resistance, and a second layer of plant defense, mediated by resistance (R) proteins, leading to a complete resistance response often accompanied by the hypersensitive cell death (HR), and called effector-triggered immunity (ETI; Jones & Dangl, 2006). Another form of resistance, that confers partial resistance to pathogens and usually referred as quantitative disease resistance (QDR), has been extensively observed in crops and natural plant populations (Kover & Cheverud, 2007; Poland et al., 2009; Roux et al., 2014). However, there is still very limited information about the molecular mechanisms underlying this form of immunity. More generally, protein kinases play critical roles during immunity in signaling through phosphorylation of target proteins and as modulators of cell metabolism and gene expression (Romeis, 2001; Meng & Zhang, 2013). Pseudokinases are topologically related to protein kinases but lack catalytic residue(s) classically required for phosphotransfer. Interestingly, recent reports identified two Arabidopsis pseudokinases, RKS1 and ZED1, that belong to a gene cluster within the receptor-like cytoplasmic kinase (RLCK)-XII-2 subfamily and confer different forms of immunity....

 

Fabrice Roux, Laurent Noël, Susana Rivas and Dominique Roby

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BMC Genomics: Secretome analysis reveals effector candidates associated with broad host range necrotrophy in the fungal plant pathogen Sclerotinia sclerotiorum (2014)

BMC Genomics: Secretome analysis reveals effector candidates associated with broad host range necrotrophy in the fungal plant pathogen Sclerotinia sclerotiorum (2014) | Effectors and Plant Immunity | Scoop.it

Background - The white mold fungus Sclerotinia sclerotiorum is a devastating necrotrophic plant pathogen with a remarkably broad host range. The interaction of necrotrophs with their hosts is more complex than initially thought, and still poorly understood.

Results - We combined bioinformatics approaches to determine the repertoire of S. sclerotiorum effector candidates and conducted detailed sequence and expression analyses on selected candidates. We identified 486 S. sclerotiorum secreted protein genes expressed in planta, many of which have no predicted enzymatic activity and may be involved in the interaction between the fungus and its hosts. We focused on those showing (i) protein domains and motifs found in known fungal effectors, (ii) signatures of positive selection, (iii) recent gene duplication, or (iv) being S. sclerotiorum-specific. We identified 78 effector candidates based on these properties. We analyzed the expression pattern of 16 representative effector candidate genes on four host plants and revealed diverse expression patterns.

Conclusions - These results reveal diverse predicted functions and expression patterns in the repertoire of S. sclerotiorum effector candidates. They will facilitate the functional analysis of fungal pathogenicity determinants and should prove useful in the search for plant quantitative disease resistance components active against the white mold.


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Bacterial spot detected on almonds in California (US)

Bacterial spot detected on almonds in California (US) | Effectors and Plant Immunity | Scoop.it

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Anne-Sophie Roy's curator insight, January 31, 3:17 AM

Bacterial spot caused by Xanthomonas arboricola pv. pruni is causing some damage on almond trees in the San Joaquin Valley in California (US).

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Programmable DNA-binding proteins from Burkholderia provide a fresh perspective on the TALE-like repeat domain - Nucl. Acids Res.

Programmable DNA-binding proteins from Burkholderia provide a fresh perspective on the TALE-like repeat domain - Nucl. Acids Res. | Effectors and Plant Immunity | Scoop.it

de Lange et al, 2014

The tandem repeats of transcription activator like effectors (TALEs) mediate sequence-specific DNA binding using a simple code. Naturally, TALEs are injected by Xanthomonas bacteria into plant cells to manipulate the host transcriptome. In the laboratory TALE DNA binding domains are reprogrammed and used to target a fused functional domain to a genomic locus of choice. Research into the natural diversity of TALE-like proteins may provide resources for the further improvement of current TALE technology. Here we describe TALE-like proteins from the endosymbiotic bacterium Burkholderia rhizoxinica, termed Bat proteins. Bat repeat domains mediate sequence-specific DNA binding with the same code as TALEs, despite less than 40% sequence identity. We show that Bat proteins can be adapted for use as transcription factors and nucleases and that sequence preferences can be reprogrammed. Unlike TALEs, the core repeats of each Bat protein are highly polymorphic. This feature allowed us to explore alternative strategies for the design of custom Bat repeat arrays, providing novel insights into the functional relevance of non-RVD residues. The Bat proteins offer fertile grounds for research into the creation of improved programmable DNA-binding proteins and comparative insights into TALE-like evolution.


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Science: Structural Basis for Assembly and Function of a Heterodimeric Plant Immune Receptor (2014)

Science: Structural Basis for Assembly and Function of a Heterodimeric Plant Immune Receptor (2014) | Effectors and Plant Immunity | Scoop.it

Cytoplasmic plant immune receptors recognize specific pathogen effector proteins and initiate effector-triggered immunity. In Arabidopsis, the immune receptors RPS4 and RRS1 are both required to activate defense to three different pathogens. We show that RPS4 and RRS1 physically associate. Crystal structures of the N-terminal Toll–interleukin-1 receptor/resistance (TIR) domains of RPS4 and RRS1, individually and as a heterodimeric complex (respectively at 2.05, 1.75, and 2.65 angstrom resolution), reveal a conserved TIR/TIR interaction interface. We show that TIR domain heterodimerization is required to form a functional RRS1/RPS4 effector recognition complex. The RPS4 TIR domain activates effector-independent defense, which is inhibited by the RRS1 TIR domain through the heterodimerization interface. Thus, RPS4 and RRS1 function as a receptor complex in which the two components play distinct roles in recognition and signaling.

 

Simon J. Williams, Kee Hoon Sohn, Li Wan, Maud Bernoux,  Panagiotis F. Sarris, Cecile Segonzac, Thomas Ve, Yan Ma, Simon B. Saucet, Daniel J. Ericsson, Lachlan W. Casey, Thierry Lonhienne, Donald J. Winzor, Xiaoxiao Zhang, Anne Coerdt, Jane E. Parker, Peter N. Dodds, Bostjan Kobe, Jonathan D. G. Jones

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3rd International Summer School “From genes to ecosystems” (12-18 July 2014). Labex TULIP, Toulouse

3rd International Summer School “From genes to ecosystems” (12-18 July 2014). Labex TULIP, Toulouse | Effectors and Plant Immunity | Scoop.it

This Summer School in Integrative Ecology and Biology in english is part of the TULIP Labex (Laboratory of Excellence) training program of the  and will take place in the French Pyrenees in a grandiose scenery at the foot of the well-known “Pic du Midi”, a 2800m-high mountain with one of the last functional astronomy observatories in Europe.

 

Some international researchers will participate to this event. Below the list of those who have already confirmed their participation:

Julio Salinas (Spain - Departamento de Biología Medioambiental)

Patricia Beldade (Portugal - Evolutionary Biology, Instituto Gulbenkian de Ciencia)

Uta Paszkowski (UK - Department of Plant Science)

Thierry Rigaud (France - Biogosciences Laboratory)

Mike Hochberg (France - Institute of Evolutionary Sciences, fellow in Berlin)

Janet Rankin (UK - Teaching & Learning Laboratory)

Eleanor Gilroy (UK, The James Hutton Institute)

 

 

Through plenary lectures and workshops, the program will cover many features of organism-organism interactions from both ecological and biological points of view. The programme will also include visit of unique place like the Experimental Ecology Center of CNRS in Moulis... At a glance :

Actively participate in elaborating research projects during workshops,Meet experts from Toulouse and other internationally renowned laboratories,Enjoy the inspiring Pyrenees location chosen for the Summer School.

 

Free accommodation is provided for all participants, limited in number to a total of 25 (undergraduate, graduate and post-docs)

 

 

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Scooped by Nicolas Denancé
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New Phytol.: Virtual issue on Phytopathogen effector proteins (2014)

Read also the introduction to this issue by Hannah Kuhn and Ralph Panstruga

http://onlinelibrary.wiley.com/doi/10.1111/nph.12804/pdf

 

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Rescooped by Nicolas Denancé from Publications
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Frontiers Plant Science: The genome sequence and effector complement of the flax rust pathogen Melampsora lini (2014)

Frontiers Plant Science: The genome sequence and effector complement of the flax rust pathogen Melampsora lini (2014) | Effectors and Plant Immunity | Scoop.it

Rust fungi cause serious yield reductions on crops, including wheat, barley, soybean, coffee, and represent real threats to global food security. Of these fungi, the flax rust pathogen Melampsora lini has been developed extensively over the past 80 years as a model to understand the molecular mechanisms that underpin pathogenesis. During infection, M. lini secretes virulence effectors to promote disease. The number of these effectors, their function and their degree of conservation across rust fungal species is unknown. To assess this, we sequenced and assembled de novo the genome of M. lini isolate CH5 into 21,130 scaffolds spanning 189 Mbp (scaffold N50 of 31 kbp). Global analysis of the DNA sequence revealed that repetitive elements, primarily retrotransposons, make up at least 45% of the genome. Using ab initio predictions, transcriptome data and homology searches, we identified 16,271 putative protein-coding genes. An analysis pipeline was then implemented to predict the effector complement of M. lini and compare it to that of the poplar rust, wheat stem rust and wheat stripe rust pathogens to identify conserved and species-specific effector candidates. Previous knowledge of four cloned M. lini avirulence effector proteins and two basidiomycete effectors was used to optimise parameters of the effector prediction pipeline. Markov clustering based on sequence similarity was performed to group effector candidates from all four rust pathogens. Clusters containing at least one member from M. lini were further analysed and prioritized based on features including expression in isolated haustoria and infected leaf tissue and conservation across rust species. Herein, we describe 200 of 940 clusters that ranked highest on our priority list, representing 725 flax rust candidate effectors. Our findings on this important model rust species provide insight into how effectors of rust fungi are conserved across species and how they may act to promote infection on their hosts.


Via Francis Martin, Kamoun Lab @ TSL
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Francis Martin's curator insight, March 4, 2:30 PM

A long awaited genome! More rust genomes needed.