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Rescooped by Ronaldo Dalio from Plants and Microbes
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New Phytologist: Convergent evolution of filamentous microbes towards evasion of glycan-triggered immunity (2016)

New Phytologist: Convergent evolution of filamentous microbes towards evasion of glycan-triggered immunity (2016) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

All filamentous microbes produce and release a wide range of glycans, which are essential determinants of microbe–microbe and microbe–host interactions. Major cell wall constituents, such as chitin and β-glucans, are elicitors of host immune responses. The widespread capacity for glycan perception in plants has driven the evolution of various strategies that help filamentous microbes to evade detection. Common strategies include structural and chemical modifications of cell wall components as well as the secretion of effector proteins that suppress chitin- and β-glucan-triggered immune responses. Thus, the necessity to avoid glycan-triggered immunity represents a driving force in the convergent evolution of filamentous microbes towards its suppression.


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Rescooped by Ronaldo Dalio from Plants and Microbes
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Plant Cell: Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors (2015)

Plant Cell: Plants Release Precursors of Histone Deacetylase Inhibitors to Suppress Growth of Competitors (2015) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

To secure their access to water, light, and nutrients, many plant species have developed allelopathic strategies to suppress competitors. To this end, they release into the rhizosphere phytotoxic substances that inhibit the germination and growth of neighbors. Despite the importance of allelopathy in shaping natural plant communities and for agricultural production, the underlying molecular mechanisms are largely unknown. Here, we report that allelochemicals derived from the common class of cyclic hydroxamic acid root exudates directly affect the chromatin-modifying machinery in Arabidopsis thaliana. These allelochemicals inhibit histone deacetylases both in vitro and in vivo and exert their activity through locus-specific alterations of histone acetylation and associated gene expression. Our multilevel analysis collectively shows how plant-plant interactions interfere with a fundamental cellular process, histone acetylation, by targeting an evolutionarily highly conserved class of enzymes.


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PLOS ONE: Heterologous Expression Screens in Nicotiana benthamiana Identify a Candidate Effector of the Wheat Yellow Rust Pathogen that Associates with Processing Bodies (2016)

PLOS ONE: Heterologous Expression Screens in  Nicotiana benthamiana  Identify a Candidate Effector of the Wheat Yellow Rust Pathogen that Associates with Processing Bodies (2016) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

Rust fungal pathogens of wheat (Triticum spp.) affect crop yields worldwide. The molecular mechanisms underlying the virulence of these pathogens remain elusive, due to the limited availability of suitable molecular genetic research tools. Notably, the inability to perform high-throughput analyses of candidate virulence proteins (also known as effectors) impairs progress. We previously established a pipeline for the fast-forward screens of rust fungal candidate effectors in the model plant Nicotiana benthamiana. This pipeline involves selecting candidate effectors in silico and performing cell biology and protein-protein interaction assays in planta to gain insight into the putative functions of candidate effectors. In this study, we used this pipeline to identify and characterize sixteen candidate effectors from the wheat yellow rust fungal pathogen Puccinia striiformis f sp tritici. Nine candidate effectors targeted a specific plant subcellular compartment or protein complex, providing valuable information on their putative functions in plant cells. One candidate effector, PST02549, accumulated in processing bodies (P-bodies), protein complexes involved in mRNA decapping, degradation, and storage. PST02549 also associates with the P-body-resident ENHANCER OF mRNA DECAPPING PROTEIN 4 (EDC4) from N. benthamiana and wheat. We propose that P-bodies are a novel plant cell compartment targeted by pathogen effectors.


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Mol Cell Proteomics: Comparative Secretome Analysis of Ralstonia solanacearum Type 3 Secretion-Associated Mutants Reveals a Fine Control of Effector Delivery, Essential for Bacterial Pathogenicity ...

Mol Cell Proteomics: Comparative Secretome Analysis of Ralstonia solanacearum Type 3 Secretion-Associated Mutants Reveals a Fine Control of Effector Delivery, Essential for Bacterial Pathogenicity ... | Hot topics on Science, biotechnology and plant pathology | Scoop.it

Ralstonia solanacearum, the causal agent of bacterial wilt, exerts its pathogenicity through more than a hundred secreted proteins, many of them depending directly on the functionality of a type 3 secretion system (T3SS). To date, only few type 3 effectors (T3Es) have been identified as required for bacterial pathogenicity, notably due to redundancy among the large R. solanacearum effector repertoire. In order to identify groups of effectors collectively promoting disease on susceptible hosts, we investigated the role of putative post-translational regulators in the control of type 3 secretion. A shotgun secretome analysis with label-free quantification using tandem mass spectrometry was performed on the R. solanacearum GMI1000 strain. 228 proteins were identified, among which a large proportion of T3Es, called Rip (Ralstonia injected proteins). Thanks to this proteomic approach, RipBJ was identified as a new effector specifically secreted through T3SS and translocated into plant cells. A focused Rip secretome analysis using hpa (hypersensitive response and pathogenicity associated) mutants revealed a fine secretion regulation and specific subsets of Rips with different secretion patterns. We showed that a set of Rips (RipF1, RipW, RipX, RipAB and RipAM) are secreted in an Hpa-independent manner. We hypothesize that these Rips could be preferentially involved in the first stages of type 3 secretion. In addition, the secretion of about thirty other Rips is controlled by HpaB and HpaG. HpaB, a candidate chaperone was demonstrated to positively control secretion of numerous Rips, while HpaG was shown to act as a negative regulator of secretion. To evaluate the impact of altered T3E secretion on plant pathogenesis, the hpa mutants were assayed on several host plants. HpaB was required for bacterial pathogenicity on multiple hosts whereas HpaG was found to be specifically required for full R. solanacearum pathogenicity on the legume plant Medicago truncatula.


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Rescooped by Ronaldo Dalio from Publications from The Sainsbury Laboratory
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Curr Opin Plant Biol: Should I stay or should I go? Traffic control for plant pattern recognition receptors (2015)

Curr Opin Plant Biol: Should I stay or should I go? Traffic control for plant pattern recognition receptors (2015) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

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The Sainsbury Lab's curator insight, September 8, 2015 4:10 AM

Plants employ cell surface-localised receptors to recognise potential invaders via perception of microbe-derived molecules. This is mediated by pattern recognition receptors (PRRs) that bind microbe-associated or damage-associated molecular patterns or perceive apoplastic effector proteins secreted by microorganisms. In either case, effective recognition and initiation of appropriate defence responses rely on a signalling competent pool of receptors at the cell surface. Maintenance of this pool of receptors at the plasma membrane is guaranteed by sorting of properly folded ligand-unbound and ligand-bound receptors via the secretory-endosomal network in an activation-dependent manner. Recent findings highlight that ligand-induced endocytosis is found across members of distinct PRR families suggesting a conserved mechanism by which PRRs and immunity is regulated.

Rescooped by Ronaldo Dalio from Plant Immunity And Microbial Effectors
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Crosstalk between nitric oxide and glutathione is required for NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1)-dependent defense signaling in Arabidopsis thaliana

Crosstalk between nitric oxide and glutathione is required for NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1)-dependent defense signaling in Arabidopsis thaliana | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Summary
Nitric oxide (NO) is a ubiquitous signaling molecule involved in a wide range of physiological and pathophysiological processes in animals and plants.

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Rescooped by Ronaldo Dalio from Plant immunity and legume symbiosis
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Nuclear processes associated with plant immunity and pathogen susceptibility

Nuclear processes associated with plant immunity and pathogen susceptibility | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Plants are sessile organisms that have evolved exquisite and sophisticated mechanisms to adapt to their biotic and abiotic environment. Plants deploy receptors and vast signalling networks to detect, transmit and respond to a given biotic threat by inducing properly dosed defence responses. Genetic analyses and, more recently, next-generation -omics approaches have allowed unprecedented insights into the mechanisms that drive immunity. Similarly, functional genomics and the emergence of pathogen genomes have allowed reciprocal studies on the mechanisms governing pathogen virulence and host susceptibility, collectively allowing more comprehensive views on the processes that govern disease and resistance. Among others, the identification of secreted pathogen molecules (effectors) that modify immunity-associated processes has changed the plant–microbe interactions conceptual landscape. Effectors are now considered both important factors facilitating disease and novel probes, suited to study immunity in plants. In this review, we will describe the various mechanisms and processes that take place in the nucleus and help regulate immune responses in plants. Based on the premise that any process required for immunity could be targeted by pathogen effectors, we highlight and describe a number of functional assays that should help determine effector functions and their impact on immune-related processes. The identification of new effector functions that modify nuclear processes will help dissect nuclear signalling further and assist us in our bid to bolster immunity in crop plants.

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Jennifer Mach's curator insight, April 13, 2015 8:34 AM

The abstract opens with the classic "plants are sessile organisms" gambit...

Rescooped by Ronaldo Dalio from Plant immunity and legume symbiosis
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Transcriptional networks in plant immunity

Transcriptional networks in plant immunity | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Next to numerous abiotic stresses, plants are constantly exposed to a variety of pathogens within their environment. Thus, their ability to survive and prosper during the course of evolution was strongly dependent on adapting efficient strategies to perceive and to respond to such potential threats. It is therefore not surprising that modern plants have a highly sophisticated immune repertoire consisting of diverse signal perception and intracellular signaling pathways. This signaling network is intricate and deeply interconnected, probably reflecting the diverse lifestyles and infection strategies used by the multitude of invading phytopathogens. Moreover it allows signal communication between developmental and defense programs thereby ensuring that plant growth and fitness are not significantly retarded. How plants integrate and prioritize the incoming signals and how this information is transduced to enable appropriate immune responses is currently a major research area. An important finding has been that pathogen-triggered cellular responses involve massive transcriptional reprogramming within the host. Additional key observations emerging from such studies are that transcription factors (TFs) are often sites of signal convergence and that signal-regulated TFs act in concert with other context-specific TFs and transcriptional co-regulators to establish sensory transcription regulatory networks required for plant immunity.

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Nature Plants: Elicitin recognition confers enhanced resistance to Phytophthora infestans in potato (2015)

Nature Plants: Elicitin recognition confers enhanced resistance to Phytophthora infestans in potato (2015) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

Potato late blight, caused by the destructive Irish famine pathogen Phytophthora infestans, is a major threat to global food security1,2. All late blight resistance genes identified to date belong to the coiled-coil, nucleotide-binding, leucine-rich repeat class of intracellular immune receptors3. However, virulent races of the pathogen quickly evolved to evade recognition by these cytoplasmic immune receptors4. Here we demonstrate that the receptor-like protein ELR (elicitin response) from the wild potato Solanum microdontum mediates extracellular recognition of the elicitin domain, a molecular pattern that is conserved in Phytophthora species. ELR associates with the immune co-receptor BAK1/SERK3 and mediates broad-spectrum recognition of elicitin proteins from several Phytophthora species, including four diverse elicitins from P. infestans. Transfer of ELR into cultivated potato resulted in enhanced resistance to P. infestans. Pyramiding cell surface pattern recognition receptors with intracellular immune receptors could maximize the potential of generating a broader and potentially more durable resistance to this devastating plant pathogen.


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Rescooped by Ronaldo Dalio from Plant Immunity And Microbial Effectors
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Recognition and Activation Domains Contribute to Allele-Specific Responses of an Arabidopsis NLR Receptor to an Oomycete Effector Protein

Recognition and Activation Domains Contribute to Allele-Specific Responses of an Arabidopsis NLR Receptor to an Oomycete Effector Protein | Hot topics on Science, biotechnology and plant pathology | Scoop.it
by Adam D. Steinbrenner, Sandra Goritschnig, Brian J. Staskawicz
In plants, specific recognition of pathogen effector proteins by nucleotide-binding leucine-rich repeat (NLR) receptors leads to activation of immune responses.

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Effector discovery in the fungal wheat pathogen Zymoseptoria tritici

Effector discovery in the fungal wheat pathogen Zymoseptoria tritici | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Summary
Fungal plant pathogens such as Zymoseptoria tritici (formerly known as Mycosphaerella graminicola) secrete repertoires of effectors facilitating infection or triggering host defence mechanisms.

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Transcriptome and metabolome reprogramming in Vitis vinifera cv. Trincadeira berries upon infection with Botrytis cinerea

Transcriptome and metabolome reprogramming in Vitis vinifera cv. Trincadeira berries upon infection with Botrytis cinerea | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Highlight Botrytis-infected grapes are able to initiate a basal defence response by reprogramming the transcriptome and metabolome but lack important defences that are naturally established in healthy ripening berries.

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Rescooped by Ronaldo Dalio from Plants and Microbes
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5th Xanthomonas Genomics Conference, July 8 - 11, 2015, Bogotá, Colombia

5th Xanthomonas Genomics Conference, July 8 - 11, 2015, Bogotá, Colombia | Hot topics on Science, biotechnology and plant pathology | Scoop.it

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Rescooped by Ronaldo Dalio from Plants and Microbes
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bioRxiv: NLR signaling network mediates immunity to diverse plant pathogens (2016)

bioRxiv: NLR signaling network mediates immunity to diverse plant pathogens (2016) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

Plant and animal nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins often function in pairs to mediate innate immunity to pathogens. However, the degree to which NLR proteins form signaling networks beyond genetically linked pairs is poorly understood. In this study, we discovered that a large NLR immune signaling network with a complex genetic architecture confers immunity to oomycetes, bacteria, viruses, nematodes, and insects. The network emerged over 100 million years ago from a linked NLR pair that diversified into up to one half of the NLR of asterid plants. We propose that this NLR network increases robustness of immune signaling to counteract rapidly evolving plant pathogens.


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Science: Intracellular innate immune surveillance devices in plants and animals (2016)

Science: Intracellular innate immune surveillance devices in plants and animals (2016) | Hot topics on Science, biotechnology and plant pathology | Scoop.it
The innate immune systems of both plants and animals depend on the ability to recognize pathogen-derived molecules and stimulate a defense response. Jones et al. review how that common function is achieved in such diverse kingdoms by similar molecules. The recognition system is built for hair-trigger sensitivity and constructed in a modular manner. Understanding such features could be useful in building new pathways through synthetic biology, whether for broadening disease defenses or constructing new signal-response circuits.Empty description

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The Sainsbury Lab's curator insight, December 2, 4:06 AM
The innate immune systems of both plants and animals depend on the ability to recognize pathogen-derived molecules and stimulate a defense response. Jones et al. review how that common function is achieved in such diverse kingdoms by similar molecules. The recognition system is built for hair-trigger sensitivity and constructed in a modular manner. Understanding such features could be useful in building new pathways through synthetic biology, whether for broadening disease defenses or constructing new signal-response circuits.
Rescooped by Ronaldo Dalio from Plants and Microbes
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Frontiers: Avirulence genes in cereal powdery mildews: the gene-for-gene hypothesis 2.0 (2016)

Frontiers: Avirulence genes in cereal powdery mildews: the gene-for-gene hypothesis 2.0 (2016) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

The gene-for-gene hypothesis states that for each gene controlling resistance in the host, there is a corresponding, specific gene controlling avirulence in the pathogen. Allelic series of the cereal mildew resistance genes Pm3 and Mla provide an excellent system for genetic and molecular analysis of resistance specificity. Despite this opportunity for molecular research, avirulence genes in mildews remain underexplored. Earlier work in barley powdery mildew (B.g. hordei) has shown that the reaction to some Mla resistance alleles is controlled by multiple genes. Similarly, several genes are involved in the specific interaction of wheat mildew (B.g. tritici) with the Pm3 allelic series. We found that two mildew genes control avirulence on Pm3f: one gene is involved in recognition by the resistance protein as demonstrated by functional studies in wheat and the heterologous host Nicotiana benthamiana. A second gene is a suppressor, and resistance is only observed in mildew genotypes combining the inactive suppressor and the recognized Avr. We propose that such suppressor/avirulence gene combinations provide the basis of specificity in mildews. Depending on the particular gene combinations in a mildew race, different genes will be genetically identified as the “avirulence” gene. Additionally, the observation of two LINE retrotransposon-encoded avirulence genes in B.g. hordei further suggests that the control of avirulence in mildew is more complex than a canonical gene-for-gene interaction. To fully understand the mildew-cereal interactions, more knowledge on avirulence determinants is needed and we propose ways how this can be achieved based on recent advances in the field.


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Rescooped by Ronaldo Dalio from Plants and Microbes
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BMC Biology: Integrated decoys and effector traps: how to catch a plant pathogen (2016)

BMC Biology: Integrated decoys and effector traps: how to catch a plant pathogen (2016) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

Plant immune receptors involved in disease resistance and crop protection are related to the animal Nod-like receptor (NLR) class, and recognise the virulence effectors of plant pathogens, whereby they arm the plant’s defensive response. Although plant NLRs mainly contain three protein domains, about 10 % of these receptors identified by extensive cross-plant species data base searches have now been shown to include novel and highly variable integrated domains, some of which have been shown to detect pathogen effectors by direct interaction. Sarris et al. have identified a large number of integrated domains that can be used to detect effector targets in host plant proteomes and identify unknown pathogen effectors.

 

Please see related Research article: Comparative analysis of plant immune receptor architectures uncovers host proteins likely targeted by pathogens, http://dx.doi.org/10.1186/s12915-016-0228-7

 

Since the time of writing, a closely related paper has been released: Kroj T, Chanclud E, Michel-Romiti C, Grand X, Morel J-B. Integration of decoy domains derived from protein targets of pathogen effectors into plant immune receptors is widespread. New Phytol. 2016 


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Microbiology and Molecular Biology Reviews: Oomycete Interactions with Plants: Infection Strategies and Resistance Principles

Microbiology and Molecular Biology Reviews: Oomycete Interactions with Plants: Infection Strategies and Resistance Principles | Hot topics on Science, biotechnology and plant pathology | Scoop.it

The Oomycota include many economically significant microbial pathogens of crop species. Understanding the mechanisms by which oomycetes infect plants and identifying methods to provide durable resistance are major research goals. Over the last few years, many elicitors that trigger plant immunity have been identified, as well as host genes that mediate susceptibility to oomycete pathogens. The mechanisms behind these processes have subsequently been investigated and many new discoveries made, marking a period of exciting research in the oomycete pathology field. This review provides an introduction to our current knowledge of the pathogenic mechanisms used by oomycetes, including elicitors and effectors, plus an overview of the major principles of host resistance: the established R gene hypothesis and the more recently defined susceptibility (S) gene model. Future directions for development of oomycete-resistant plants are discussed, along with ways that recent discoveries in the field of oomycete-plant interactions are generating novel means of studying how pathogen and symbiont colonizations overlap.


Via Kamoun Lab @ TSL, Francis Martin, IPM Lab
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Salicylic acid biosynthesis is enhanced and contributes to increased biotrophic pathogen resistance in Arabidopsis hybrids

Salicylic acid biosynthesis is enhanced and contributes to increased biotrophic pathogen resistance in Arabidopsis hybrids | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Article
The molecular basis for heterosis, the phenomenon whereby hybrid plants show phenotypic superiority to their parents, remains poorly understood. Here, Yang et al .

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Frontiers | Signal regulators of systemic acquired resistance | Plant-Microbe Interaction

Frontiers | Signal regulators of systemic acquired resistance | Plant-Microbe Interaction | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Salicylic acid (SA) is an important phytohormone that plays a vital role in a number of physiological responses, including plant defense. The last two decades have witnessed a number of breakthroughs related to biosynthesis, transport, perception and signaling mediated by SA. These findings demonstrate that SA plays a crictical role in both local and systemic defense responses. Systemic acquired resistance (SAR) is one such SA-dependent response. SAR is a long distance signaling mechanism that provides broad spectrum and long-lasting resistance to secondary infections throughout the plant. This unique feature makes SAR a highly desirable trait in crop production. This review summarizes the recent advances in the role of SA in SAR and discusses its relationship to other SAR inducers.

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Secondary metabolites in plant innate immunity

Secondary metabolites in plant innate immunity | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Plant secondary metabolites carry out numerous functions in interactions between plants and a broad range of other organisms. Experimental evidence strongly supports the indispensable contribution of many constitutive and pathogen-inducible phytochemicals to plant innate immunity. Extensive studies on model plant species, particularly Arabidopsis thaliana, have brought significant advances in our understanding of the molecular mechanisms underpinning pathogen-triggered biosynthesis and activation of defensive secondary metabolites. However, despite the proven significance of secondary metabolites in plant response to pathogenic microorganisms, little is known about the precise mechanisms underlying their contribution to plant immunity. This insufficiency concerns information on the dynamics of cellular and subcellular localization of defensive phytochemicals during the encounters with microbial pathogens and precise knowledge on their mode of action. As many secondary metabolites are characterized by their in vitro antimicrobial activity, these compounds were commonly considered to function in plant defense as in planta antibiotics. Strikingly, recent experimental evidence suggests that at least some of these compounds alternatively may be involved in controlling several immune responses that are evolutionarily conserved in the plant kingdom, including callose deposition and programmed cell death.

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Rescooped by Ronaldo Dalio from TAL effector science
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Gene targeting by the TAL effector PthXo2 reveals cryptic resistance gene for bacterial blight of rice - Plant J.

Gene targeting by the TAL effector PthXo2 reveals cryptic resistance gene for bacterial blight of rice - Plant J. | Hot topics on Science, biotechnology and plant pathology | Scoop.it

(via T. Schreiber, thx)

Bacterial blight of rice is caused by the γ-proteobacterium Xanthomonas oryzae pv. oryzae, which utilizes a group of type III TAL (transcription activator-like) effectors to induce host gene expression and condition host susceptibility. Five SWEET genes are functionally redundant to support bacterial disease, but only two were experimentally proven targets of natural TAL effectors. Here, we report the identification of the sucrose transporter gene OsSWEET13 as the disease susceptibility gene for PthXo2 and the existence of cryptic recessive resistance to PthXo2-dependent X. oryzae pv. oryzae due to promoter variations of OsSWEET13 in japonica rice. PthXo2-containing strains induce OsSWEET13 in indica rice IR24 due to the presence of an unpredicted and undescribed effector binding site not present in the alleles in japonica rice Nipponbare and Kitaake. The specificity of effector-associated gene induction and disease susceptibility is attributable to a single nucleotide polymorphism (SNP), which is also found in a polymorphic allele of OsSWEET13 known as the recessive resistance gene xa25 from the rice cultivar Minghui 63. The mutation of OsSWEET13 with CRISPR/Cas9 technology further corroborates the requirement of OsSWEET13 expression for the state of PthXo2-dependent disease susceptibility to X. oryzae pv. oryzae. Gene profiling of a collection of 104 strains revealed OsSWEET13 induction by 42 isolates of X. oryzae pv. oryzae. Heterologous expression of OsSWEET13 in Nicotiana benthamiana leaf cells elevates sucrose concentrations in the apoplasm. The results corroborate a model whereby X. oryzae pv. oryzae enhances the release of sucrose from host cells in order to exploit the host resources.

 


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Transcriptome and metabolome reprogramming in Vitis vinifera cv. Trincadeira berries upon infection with Botrytis cinerea

Transcriptome and metabolome reprogramming in Vitis vinifera cv. Trincadeira berries upon infection with Botrytis cinerea | Hot topics on Science, biotechnology and plant pathology | Scoop.it
Highlight Botrytis-infected grapes are able to initiate a basal defence response by reprogramming the transcriptome and metabolome but lack important defences that are naturally established in healthy ripening berries.

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MPMI: Candidate Effector Proteins of the Rust Pathogen Melampsora Larici-Populina Target Diverse Plant Cell Compartments (2015)

MPMI: Candidate Effector Proteins of the Rust Pathogen Melampsora Larici-Populina Target Diverse Plant Cell Compartments (2015) | Hot topics on Science, biotechnology and plant pathology | Scoop.it

Rust fungi are devastating crop pathogens that deliver effector proteins into infected tissues to modulate plant functions and promote parasitic growth. The genome of the poplar leaf rust fungus Melampsora larici-populina revealed a large catalogue of secreted proteins, some of which have been considered candidate effectors. Unravelling how these proteins function in host cells is key to understanding pathogenicity mechanisms and developing resistant plants. In this study, we used an effectoromics pipeline to select, clone, and express 20 candidate effectors in Nicotiana benthamiana leaf cells to determine their subcellular localisation and identify the plant proteins they interact with. Confocal microscopy revealed that six candidate effectors target the nucleus, nucleoli, chloroplasts, mitochondria and discrete cellular bodies. We also used coimmunoprecipitation and mass spectrometry to identify 606 N. benthamiana proteins that associate with the candidate effectors. Five candidate effectors specifically associated with a small set of plant proteins that may represent biologically relevant interactors. We confirmed the interaction between the candidate effector MLP124017 and the TOPLESS-Related Protein 4 from poplar by in planta coimmunoprecipitation. Altogether, our data enable us to validate effector proteins from M. larici-populina and reveal that these proteins may target multiple compartments and processes in plant cells. It also shows that N. benthamiana can be a powerful heterologous system to study effectors of obligate biotrophic pathogens.


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The Sainsbury Lab's curator insight, February 5, 2015 7:23 AM

Rust fungi are devastating crop pathogens that deliver effector proteins into infected tissues to modulate plant functions and promote parasitic growth. The genome of the poplar leaf rust fungus Melampsora larici-populina revealed a large catalogue of secreted proteins, some of which have been considered candidate effectors. Unravelling how these proteins function in host cells is key to understanding pathogenicity mechanisms and developing resistant plants. In this study, we used an effectoromics pipeline to select, clone, and express 20 candidate effectors in Nicotiana benthamiana leaf cells to determine their subcellular localisation and identify the plant proteins they interact with. Confocal microscopy revealed that six candidate effectors target the nucleus, nucleoli, chloroplasts, mitochondria and discrete cellular bodies. We also used coimmunoprecipitation and mass spectrometry to identify 606 N. benthamiana proteins that associate with the candidate effectors. Five candidate effectors specifically associated with a small set of plant proteins that may represent biologically relevant interactors. We confirmed the interaction between the candidate effector MLP124017 and the TOPLESS-Related Protein 4 from poplar by in planta coimmunoprecipitation. Altogether, our data enable us to validate effector proteins from M. larici-populina and reveal that these proteins may target multiple compartments and processes in plant cells. It also shows that N. benthamiana can be a powerful heterologous system to study effectors of obligate biotrophic pathogens.

Rescooped by Ronaldo Dalio from Plant Immunity And Microbial Effectors
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How the necrotrophic fungus Alternaria brassicicola kills plant cells remains an enigma [PublishAheadOfPrint]

Alternaria species are mainly saprophytic fungi but some are plant pathogens. Seven pathotypes of Alternaria alternata use secondary metabolites of host-specific toxins as pathogenicity factors. These toxins kill host cells prior to colonization.

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