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OpenAshDieBack: A hub for crowdsourcing information and genomic resources for Ash Dieback

OpenAshDieBack: A hub for crowdsourcing information and genomic resources for Ash Dieback | Plant-Microbe Interaction | Scoop.it
Welcome to Open Access Data and Crowdsourced analyses!

On this website you'll be able to get data to do your own analyses on ash and ash dieback. You can see the results of other peoples work as soon as it is available and share your own discoveries in the same way.

You will always get full credit for your work and in doing so contribute to a real community effort.

Via Kamoun Lab @ TSL
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Rescooped by Guogen Yang from Plant-microbe interaction
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J. Exp. Bot.: Greasy tactics in the plant–pathogen molecular arms race (2015)

J. Exp. Bot.: Greasy tactics in the plant–pathogen molecular arms race (2015) | Plant-Microbe Interaction | Scoop.it

The modification of proteins by the attachment of fatty acids is a targeting tactic involved in mechanisms of both plant immunity and bacterial pathogenesis. The plant plasma membrane (PM) is a key battleground in the war against disease-causing microbes. This membrane is armed with an array of sensor proteins that function as a surveillance system to detect invading pathogens. Several of these sensor proteins are directed to the plasma membrane through the covalent addition of fatty acids, a process termed fatty acylation. Phytopathogens secrete effector proteins into the plant cell to subvert these surveillance mechanisms, rendering the host susceptible to infection. The targeting of effectors to specific locales within plant cells, particularly the internal face of the host PM, is critical for their virulence function. Several bacterial effectors hijack the host fatty acylation machinery to be modified and directed to this contested locale. To find and fight these fatty acylated effectors the plant leverages lipid-modified intracellular sensors. This review provides examples featuring how fatty acylation is a battle tactic used by both combatants in the molecular arms race between plants and pathogens. Also highlighted is the exploitation of a specific form of host-mediated fatty acid modification, which appears to be exclusively employed by phytopathogenic effector proteins.

 

 


Via Nicolas Denancé, Suayib Üstün
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PLOS Pathogens: Dimorphism in Fungal Pathogens of Mammals, Plants, and Insects

PLOS Pathogens: Dimorphism in Fungal Pathogens of Mammals, Plants, and Insects | Plant-Microbe Interaction | Scoop.it

Phytopathogenic dimorphic fungi have had a major impact on urban landscapes and agriculture.Ophiostoma ulmi, which caused the first Dutch elm disease epidemic, has been replaced by a more virulent species, Ophiostoma novo-ulmi, which has destroyed millions of elm trees in the US and Europe [5]. Taphrina deformans, the etiologic agent of peach leaf curl, results in economic losses of $2.5–3 million in the US [6]. Although Ustilago maydis, which causes corn smut, is not a major agricultural threat, the galls (i.e., huitlacoche) caused by infection are eaten as a delicacy [7]. Entomopathogenic fungi have been utilized to control insects harmful to agriculture and to study how pathogens control host behavior [8,9].

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GMOs in lockdown

Genetically modified organisms (GMOs) are becoming widely used in agriculture and bioremediation, and for the production of pharmaceuticals and biofuels. However, alongside their increased use, there are growing concerns about the potential risk that these organisms could escape into the environment. Now, two studies report the design of novel GMOs that are dependent on synthetic amino acids (sAAs) and therefore cannot grow in natural ecosystems.

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The oak gene expression atlas: insights into Fagaceae genome evolution and the discovery of genes regulated during bud dormancy release

Many northern-hemisphere forests are dominated by oaks. These species extend over diverse environmental conditions and are thus interesting models for studies of plant adaptation and speciation. The genomic toolbox is an important asset for exploring the functional variation associated with natural selection. Results The assembly of previously available and newly developed long and short sequence reads for two sympatric oak species, Quercus robur and Quercus petraea, generated a comprehensive catalog of transcripts for oak. The functional annotation of 91 k contigs demonstrated the presence of a large proportion of plant genes in this unigene set. Comparisons with SwissProt accessions and five plant gene models revealed orthologous relationships, making it possible to decipher the evolution of the oak genome. In particular, it was possible to align 9.5 thousand oak coding sequences with the equivalent sequences on peach chromosomes. Finally, RNA-seq data shed new light on the gene networks underlying vegetative bud dormancy release, a key stage in development allowing plants to adapt their phenology to the environment. Conclusion In addition to providing a vast array of expressed genes, this study generated essential information about oak genome evolution and the regulation of genes associated with vegetative bud phenology, an important adaptive traits in trees. This resource contributes to the annotation of the oak genome sequence and will provide support for forward genetics approaches aiming to link genotypes with adaptive phenotypes.

Via Francis Martin
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Deep RNA sequencing reveals a high frequency of alternative splicing events in the fungus Trichoderma longibrachiatum

Background
Alternative splicing is crucial for proteome diversity and functional complexity in higher organisms. However, the alternative splicing landscape in fungi is still elusive.

Results
The transcriptome of the filamentous fungus Trichoderma longibrachiatum was deep sequenced using Illumina Solexa technology. A total of 14305 splice junctions were discovered. Analyses of alternative splicing events revealed that the number of all alternative splicing events (10034), intron retentions (IR, 9369), alternative 5’ splice sites (A5SS, 167), and alternative 3’ splice sites (A3SS, 302) is 7.3, 7.4, 5.1, and 5.9-fold higher, respectively, than those observed in the fungus Aspergillus oryzae using Illumina Solexa technology. This unexpectedly high ratio of alternative splicing suggests that alternative splicing is important to the transcriptome diversity of T. longibrachiatum. Alternatively spliced introns had longer lengths, higher GC contents, and lower splice site scores than constitutive introns. Further analysis demonstrated that the isoform relative frequencies were correlated with the splice site scores of the isoforms. Moreover, comparative transcriptomics determined that most enzymes related to glycolysis and the citrate cycle and glyoxylate cycle as well as a few carbohydrate-active enzymes are transcriptionally regulated.

Conclusions
This study, consisting of a comprehensive analysis of the alternative splicing landscape in the filamentous fungus T. longibrachiatum, revealed an unexpectedly high ratio of alternative splicing events and provided new insights into transcriptome diversity in fungi.

Via Francis Martin
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eLife: Evidence for suppression of immunity as a driver for genomic introgressions and host range expansion in races of Albugo candida, a generalist parasite (2015)

eLife: Evidence for suppression of immunity as a driver for genomic introgressions and host range expansion in races of Albugo candida, a generalist parasite (2015) | Plant-Microbe Interaction | Scoop.it

How generalist parasites with wide host ranges can evolve is a central question in parasite evolution. Albugo candida is an obligate biotrophic parasite that consists of many physiological races that each specialize on distinct Brassicaceae host species. By analyzing genome sequence assemblies of five isolates, we show they represent three races that are genetically diverged by ~1%. Despite this divergence, their genomes are mosaic-like, with ~25% being introgressed from other races. Sequential infection experiments show that infection by adapted races enables subsequent infection of hosts by normally non-infecting races. This facilitates introgression and the exchange of effector repertoires, and may enable the evolution of novel races that can undergo clonal population expansion on new hosts. We discuss recent studies on hybridization in other eukaryotes such as yeast, Heliconius butterflies, Darwin's finches, sunflowers and cichlid fishes, and the implications of introgression for pathogen evolution in an agro-ecological environment.


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NLRs in plants

Intracellular immune receptors with nucleotide-binding, leucine-rich domains (NLRs) are found in both plants and animals. Compared to animals, NLR-encoding gene families are expanded, more prevalent and have enriched diversity in higher plants. Strong host defense triggered by the recognition of specific pathogen effectors constitutes a major part of the plant immune response that has long been exploited to breed crops for enhanced resistance. Although the first plant NLR genes were cloned about 20 years ago, their signaling mechanisms remain obscure. Here we review recent progress in plant NLR studies, focusing on their pathogen recognition, homeostasis control and potential signaling activation mechanisms.

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

Vitis vinifera berries are sensitive towards infection by the necrotrophic pathogen Botrytis cinerea, leading to important economic losses worldwide. The combined analysis of the transcriptome and metabolome associated with fungal infection has not been performed previously in grapes or in another fleshy fruit. In an attempt to identify the molecular and metabolic mechanisms associated with the infection, peppercorn-sized fruits were infected in the field. Green and veraison berries were collected following infection for microarray analysis complemented with metabolic profiling of primary and other soluble metabolites and of volatile emissions. The results provided evidence of a reprogramming of carbohydrate and lipid metabolisms towards increased synthesis of secondary metabolites involved in plant defence, such as trans-resveratrol and gallic acid. This response was already activated in infected green berries with the putative involvement of jasmonic acid, ethylene, polyamines, and auxins, whereas salicylic acid did not seem to be involved. Genes encoding WRKY transcription factors, pathogenesis-related proteins, glutathione S-transferase, stilbene synthase, and phenylalanine ammonia-lyase were upregulated in infected berries. However, salicylic acid signalling was activated in healthy ripening berries along with the expression of proteins of the NBS-LRR superfamily and protein kinases, suggesting that the pathogen is able to shut down defences existing in healthy ripening berries. Furthermore, this study provided metabolic biomarkers of infection such as azelaic acid, a substance known to prime plant defence responses, arabitol, ribitol, 4-amino butanoic acid, 1-O-methyl- glucopyranoside, and several fatty acids that alone or in combination can be used to monitor Botrytisinfection early in the vineyard.

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Proteome and transcript analysis of Vitis vinifera cell cultures subjected to Botrytis cinerea infection

Gray mold caused by Botrytis cinerea is one of the most important diseases of grapevine resulting in significant reductions in yield and fruit quality. In order to examine the molecular mechanisms that characterize the interaction between B. cinerea and the host plant, the grapevine cytoplasmic proteome was analyzed by two-dimensional polyacrylamide gel electrophoresis. The interaction between Vitis vinifera cv. Gamay cells and B. cinerea was characterized by the increase in spot abundance of 30 proteins, of which 21 were successfully identified. The majority of these proteins were related to defence and stress responses and to cell wall modifications. Some of the modulated proteins have been previously found to be affected by other pathogens when they infect V. vinifera but interestingly, the proteins related to cell wall modification that were influenced by B. cinerea have not been shown to be modulated by any other pathogen studied to date. Transcript analysis using the quantitative real time polymerase chain reaction additionally revealed the up-regulation of several acidic, probably extracellular, chitinases. The results indicate that cell wall strengthening, accumulation of PR proteins and excretion of lytic enzymes are likely to be important mechanisms in the defence of grapevine against B. cinerea.

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BMC Genomics | Abstract | Comparative transcriptome profiling of a rice line carrying Xa39 and its parents triggered by Xanthomonas oryzae pv. oryzae provides novel insights into the broad-spectrum...

Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is a devastating rice disease worldwide. Xa39 is a resistance (R) gene with a broad-spectrum hypersensitive response (BSHR) to Xoo. Nevertheless, the molecular mechanisms of resistance mediated by Xa39 remain unclear. In this study, the transcriptome profiling of a rice line carrying Xa39 and its parents at the early stage of Xoo infection were investigated.
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A Recently Evolved Isoform of the Transcription Factor BES1 Promotes Brassinosteroid Signaling and Development in Arabidopsis thaliana

Brassinosteroids (BRs) are essential steroid hormones that regulate plant growth and development. The transcription factor BRI1-EMS-SUPPRESSOR1 (BES1) regulates the expression of thousands of target genes in response to BRs. Here, we report an Arabidopsis thaliana-specific long isoform of BES1, BES1-L, which has stronger activity in promoting BR signaling than the canonical and widely used short BES1-S. The BES1-L isoform contains an additional N-terminal bipartite nuclear localization signal, which strongly promotes its nuclear localization. BES1-L also promotes the nuclear localization of BES1-S and BRASSINAZOLE-RESISTANT1 via dimerization. The transcription of BES1-L andBES1-S is differentially regulated by BRs due to the presence of G-box element in the BES1-S promoter. Moreover, BES1-L uniquely exists in the majority of A. thaliana ecotypes, but not in other species, even its Brassicaceae relatives, including Arabidopsis lyrata. The phenotypes of the BES1-L overexpression lines and plants with truncated BES1-L indicate that BES1-L is a more important isoform of BES1 in Arabidopsis and may have contributed to the evolution and expansion of A. thaliana.

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Retromer Contributes to Immunity-Associated Cell Death in Arabidopsis

Retromer Contributes to Immunity-Associated Cell Death in Arabidopsis | Plant-Microbe Interaction | Scoop.it
Membrane trafficking is required during plant immune responses, but its contribution to the hypersensitive response (HR), a form of programmed cell death (PCD) associated with effector-triggered immunity, is not well understood. HR is induced by nucleotide binding-leucine-rich repeat (NB-LRR) immune receptors and can involve vacuole-mediated processes, including autophagy. We previously isolated lazarus (laz) suppressors of autoimmunity-triggered PCD in the Arabidopsis thaliana mutant accelerated cell death11 (acd11) and demonstrated that the cell death phenotype is due to ectopic activation of the LAZ5 NB-LRR. We report here that laz4 is mutated in one of three VACUOLAR PROTEIN SORTING35 (VPS35) genes. We verify that LAZ4/VPS35B is part of the retromer complex, which functions in endosomal protein sorting and vacuolar trafficking. We show that VPS35B acts in an endosomal trafficking pathway and plays a role in LAZ5-dependent acd11 cell death. Furthermore, we find that VPS35 homologs contribute to certain forms of NB-LRR protein-mediated autoimmunity as well as pathogen-triggered HR. Finally, we demonstrate that retromer deficiency causes defects in late endocytic/lytic compartments and impairs autophagy-associated vacuolar processes. Our findings indicate important roles of retromer-mediated trafficking during the HR; these may include endosomal sorting of immune components and targeting of vacuolar cargo.

Via Suayib Üstün
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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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Signal Transduction by a Fungal NOD-Like Receptor Based on Propagation of a Prion Amyloid Fold

Signal Transduction by a Fungal NOD-Like Receptor Based on Propagation of a Prion Amyloid Fold | Plant-Microbe Interaction | Scoop.it

In the fungus Podospora anserina, the [Het-s] prion induces programmed cell death by activating the HET-S pore-forming protein. The HET-s β-solenoid prion fold serves as a template for converting the HET-S prion-forming domain into the same fold. This conversion, in turn, activates the HET-S pore-forming domain. The gene immediately adjacent to het-S encodes NWD2, a Nod-like receptor (NLR) with an N-terminal motif similar to the elementary repeat unit of the β-solenoid fold. NLRs are immune receptors controlling cell death and host defense processes in animals, plants and fungi. We have proposed that, analogously to [Het-s], NWD2 can activate the HET-S pore-forming protein by converting its prion-forming region into the β-solenoid fold. Here, we analyze the ability of NWD2 to induce formation of the β-solenoid prion fold. We show that artificial NWD2 variants induce formation of the [Het-s] prion, specifically in presence of their cognate ligands. The N-terminal motif is responsible for this prion induction, and mutations predicted to affect the β-solenoid fold abolish templating activity. In vitro, the N-terminal motif assembles into infectious prion amyloids that display a structure resembling the β-solenoid fold. In vivo, the assembled form of the NWD2 N-terminal region activates the HET-S pore-forming protein. This study documenting the role of the β-solenoid fold in fungal NLR function further highlights the general importance of amyloid and prion-like signaling in immunity-related cell fate pathways.

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The Potato ERF Transcription Factor StERF3 Negatively Regulates Resistance to Phytophthora infestans and Salt Tolerance in Potato

Ethylene response factors (ERFs) are unique to the plant kingdom that plays crucial roles in plant response to various biotic and abiotic stresses. We show here that a potato StERF3, which contains ERF-associated amphiphilic repression (EAR) motif in C-terminal region, negatively regulates resistance to Phytophthora infestans and salt tolerance in potato. Promoter of the StERF3 responses to induction of salicylic acid (SA), abscisic acid (ABA), ethylene (ET) and NaCl, as well as P. infestans, the causal agent of potato late blight disease. StERF3 could bind to the GCC box element of the HIS3 promoter and activate transcription of HIS3in yeast cells. Importantly, silencing StERF3 in potato showed an enhanced foliage resistance to P. infestans and elevated plant tolerance to NaCl stress accompanied by the activation of defense related genes (PR1, NPR1and WRKY1), In contrast, StERF3-overexpressing plants showed reduced expression of these defense related genes and enhanced susceptibility toP. infestans, suggesting that StERF3 functions as a negative regulator of downstream defense- and/or stress-related genes in potato. StERF3 is localised to the nucleus. Interestingly, Yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC) test clarified that the StERF3 could interact with other proteins in cytoplasm which may lead to its re-localization between the nucleus and cytoplasm, revealing a novel means of StERF3 regulation. Taken together, these data provide new insights into the mechanism underlying how StERF3 negatively regulates late blight resistance and abiotic tolerance in potato and may have a potential in engineering late blight resistance in potato.

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Rising to the challenge: accelerated pace of discovery transforms marine virology

Marine viruses have important roles in microbial mortality, gene transfer, metabolic reprogramming and biogeochemical cycling. In this Review, we discuss recent technological advances in marine virology including the use of near-quantitative, reproducible metagenomics for large-scale investigation of viral communities and the emergence of gene-based viral ecology. We also describe the reprogramming of microbially driven processes by viral metabolic genes, the identification of novel viruses using cultivation-dependent and cultivation-independent tools, and the potential for modelling studies to provide a framework for studying virus–host interactions. These transformative advances have set a rapid pace in exploring and predicting how marine viruses manipulate and respond to their environment.

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Transcriptome sequencing and analysis of the entomopathogenic fungus Hirsutella sinensis isolated from Ophiocordyceps sinensis

Background
Ophiocordyceps sinensis, a worm and fungus combined mixture which Hirsutella sinensis is parasitic on the caterpillar body, has been used as a traditional medicine or healthy food in China for thousands of years. H. sinensis is reported as the only correct anamorph of O. sinensis and its main active ingredients are similar to the natural O. sinensis.

Results
H. sinensis L0106, asexual strain of O. sinensis, was isolated and identified in this study. Three transcriptomes of H. sinensis at different cultivation periods (growth period 3d, pre-stable period 6d and stable period 9d) were sequenced for the first time by RNA-Seq method, and 25,511 unigenes (3d), 25,214 unigenes (6d) and 16,245 unigenes (9d) were assembled and obtained, respectively. These unigenes of the three samples were further assembled into 20,822 unigenes (All), and 62.3 percent of unigenes (All) could be annotated based on protein databases. Subsequently, the genes and enzymes involved in the biosynthesis of the active ingredients according to the sequencing and annotation results were predicted. Based on the predictions, we further investigated the interaction of different pathway networks and the corresponding enzymes. Furthermore, the differentially expressed genes (DEGs) of H. sinensis grown during different developmental stages (3d-VS-6d, 3d-VS-9d and 6d-VS-9d) were globally detected and analyzed based on the data from RNA-Seq, and 764 DEGs between 3d and 6d, 1,869 DEGs between 3d and 9d, and 770 DEGs between 6d and 9d were found, respectively.

Conclusions
This work presented here would aid in understanding and carrying out future studies on the genetic basis of H. sinensis and contribute to the further artificial production and application of this organism. This study provided a substantial contribution and basis to further characterize the gene expression profiles of H. sinensis in the metabolic pathways of active ingredients.


Via Francis Martin
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J. Exp. Bot.: Greasy tactics in the plant–pathogen molecular arms race (2015)

J. Exp. Bot.: Greasy tactics in the plant–pathogen molecular arms race (2015) | Plant-Microbe Interaction | Scoop.it

The modification of proteins by the attachment of fatty acids is a targeting tactic involved in mechanisms of both plant immunity and bacterial pathogenesis. The plant plasma membrane (PM) is a key battleground in the war against disease-causing microbes. This membrane is armed with an array of sensor proteins that function as a surveillance system to detect invading pathogens. Several of these sensor proteins are directed to the plasma membrane through the covalent addition of fatty acids, a process termed fatty acylation. Phytopathogens secrete effector proteins into the plant cell to subvert these surveillance mechanisms, rendering the host susceptible to infection. The targeting of effectors to specific locales within plant cells, particularly the internal face of the host PM, is critical for their virulence function. Several bacterial effectors hijack the host fatty acylation machinery to be modified and directed to this contested locale. To find and fight these fatty acylated effectors the plant leverages lipid-modified intracellular sensors. This review provides examples featuring how fatty acylation is a battle tactic used by both combatants in the molecular arms race between plants and pathogens. Also highlighted is the exploitation of a specific form of host-mediated fatty acid modification, which appears to be exclusively employed by phytopathogenic effector proteins.

 

 


Via Nicolas Denancé, Suayib Üstün
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Post-translational protein modifications in malaria parasites

Post-translational modifications play crucial parts in regulating protein function and thereby control several fundamental aspects of eukaryotic biology, including cell signalling, protein trafficking, epigenetic control of gene expression, cell–cell interactions, and cell proliferation and differentiation. In this Review, we discuss protein modifications that have been shown to have a key role in malaria parasite biology and pathogenesis. We focus on phosphorylation, acetylation, methylation and lipidation. We provide an overview of the biological significance of these modifications and discuss prospects and progress in antimalarial drug discovery based on the inhibition of the enzymes that mediate these modifications.

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Transfection of Sclerotinia sclerotiorum with in vitro transcripts of a naturally occurring interspecific recombinant of Sclerotinia sclerotiorum hypovirus 2 significantly reduces virulence of the ...

A recombinant strain of Sclerotinia sclerotiorum hypovirus 2 (SsHV2) was identified from a North American Sclerotinia sclerotiorum isolate (#328) from lettuce (Lactuca sativa L.) by high-throughput sequencing of total RNA. The 5’ and 3’ terminal regions of the genome were determined by rapid amplification of cDNA ends. The assembled nucleotide sequence was up to 92% identical to two recently reported SsHV2 strains, but contained a deletion near its 5’ terminus of more than 1.2 kb relative to the other SsHV2 strains and an insertion of 524 nt that was distantly related to Valsa ceratosperma hypovirus 1. This suggests that the new isolate is a heterologous recombinant of SsHV2 with a yet uncharacterized hypovirus. We named the new strain Sclerotinia sclerotiorum hypovirus 2 Lactuca (SsHV2L) and deposited the sequence in Genbank with accession number KF898354. Sclerotinia sclerotiorum isolate #328 was coinfected with a strain of Sclerotinia sclerotiorum endornavirus 1 and debilitated compared to cultures of the same isolate that had been cured of virus infection by cycloheximide treatment and hyphal tipping. To determine whether SsHV2L alone could induce hypovirulence in S. sclerotiorum, a full-length cDNA of the 14,538-nt viral genome was cloned. Transcripts corresponding to the viral RNA were synthesized in vitro and transfected into a virus-free isolate of S. sclerotiorum, DK3. Isolate DK3 transfected with SsHV2L was hypovirulent on soybean and lettuce and exhibited delayed maturation of sclerotia relative to virus-free DK3, completing Koch's postulates for the association of hypovirulence with SsHV2L.

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bcpmr1 encodes a P-type Ca2+/Mn2+-ATPase mediating cell-wall integrity and virulence in the phytopathogen Botrytis cinerea

The cell wall of fungi is generally composed of an inner skeletal layer consisting of various polysaccharides surrounded by a layer of glycoproteins. These usually contain both N- and O-linked oligosaccharides, coupled to the proteins by stepwise addition of mannose residues by mannosyltransferases in the endoplasmic reticulum and the Golgi apparatus. In yeast, an essential luminal cofactor for these mannosyltransferases is Mn2+ provided by the Ca2+/Mn2+-ATPase known as Pmr1. In this study, we have identified and characterized the Botrytiscinerea pmr1 gene, the closest homolog of yeast PMR1. We hypothesized that bcpmr1 also encodes a Ca2+/Mn2+-ATPase that plays an important role in the protein glycosylation pathway. Phenotypic analysis showed that bcpmr1 null mutants displayed a significant reduction in conidial production, radial growth and diameter of sclerotia. Significant alterations in hyphal cell wall composition were observed including a 83% decrease of mannan levels and an increase in the amount of chitin and glucan. These changes were accompanied by a hypersensitivity to cell wall-perturbing agents such as Calcofluor white, Congo red and zymolyase. Importantly, the Δbcpmr1 mutant showed reduced virulence in tomato (leafs and fruits) and apple (fruits) and reduced biofilm formation. Together, our results highlight the importance of bcpmr1 for protein glycosylation, cell wall structure and virulence of B. cinerea.

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RNA degradation in antiviral immunity and autoimmunity

Post-transcriptional control determines the fate of cellular RNA molecules. Nonsense-mediated decay (NMD) provides quality control of mRNA, targeting faulty cellular transcripts for degradation by multiple nucleases including the RNA exosome. Recent findings have revealed a role for NMD in targeting viral RNA molecules, thereby restricting virus infection. Interestingly, NMD is also linked to immune responses at another level: mutations affecting the NMD or RNA exosome machineries cause chronic activation of defence programmes, resulting in autoimmune phenotypes. Here we place these observations in the context of other links between innate antiviral immunity and type I interferon mediated disease and examine two models: one in which expression or function of pathogen sensors is perturbed and one wherein host-derived RNA molecules with a propensity to activate such sensors accumulate.

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Molecular Plant-Microbe Interactions Journal - 0(ja): - Abstract

Molecular Plant-Microbe Interactions Journal - 0(ja): - Abstract | Plant-Microbe Interaction | Scoop.it

During host-pathogen interactions, pattern recognition receptors form complexes with proteins such as receptor-like kinases to elicit pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), an evolutionarily conserved plant defense program. However, little is known about the components of the receptor complex, as are the molecular events leading to PTI induced by oomycete Phytophthora pathogen. Here, we demonstrate that tomato (Solanum lycopersicum) SlSOBIR1 and SlSOBIR1-like are involved in defense responses to Phytophthora parasitica. Silencing of SlSOBIR1 and SlSOBIR1-like enhanced susceptibility to P. parasitica in tomato. Callose deposition, reactive oxygen species production, and PTI marker gene expression were compromised in SlSOBIR1- and SlSOBIR1-like–silenced plants. Interestingly, P. parasitica infection and elicitin (ParA1) treatment induced the re-localization of SlSOBIR1 from the plasma membrane to endosomal compartments, and silencing of NbSOBIR1 compromised ParA1-mediated cell death on N. benthamiana. Moreover, the SlSOBIR1 kinase domain is indispensable for ParA1 to trigger SlSOBIR1 internalization and plant cell death. Taken together, these results support the participation of solanaceous SOBIR1/EVR homologs in the perception of elicitins, and indicate their important roles in plant basal defense against oomycete pathogens.

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A new versatile microarray-based method for high-throughput screening of carbohydrate-active enzymes

A new versatile microarray-based method for high-throughput screening of carbohydrate-active enzymes | Plant-Microbe Interaction | Scoop.it
Carbohydrate-active enzymes have multiple biological roles and industrial applications. Advances in genome and transcriptome sequencing, together with associated bioinformatic tools have identified vast numbers of putative carbohydrate degrading and modifying enzymes including glycoside hydrolases and lytic polysaccharide monooxygenases. However, there is a paucity of methods for rapidly screening the activities of these enzymes. By combining the multiplexing capacity of carbohydrate microarrays with the specificity of molecular probes, we have developed a sensitive, high-throughput and versatile semi-quantitative enzyme-screening technique which requires low amounts of enzyme and substrate. The method can be used to assess the activities of single enzymes, enzyme cocktails and crude culture broths against single substrates, substrate mixtures and biomass samples. Moreover, we show that the technique can be used to analyse both endo-acting and exo-acting glycoside hydrolases, polysaccharide lyases, carbohydrate esterases and lytic polysaccharide monooxygenases. We demonstrate the potential of the technique by identifying the substrate specificities of purified un-characterised enzymes and by screening enzyme activities from fungal culture broths.

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PLOS Pathogens: Fifty Shades of Immune Defense

PLOS Pathogens: Fifty Shades of Immune Defense | Plant-Microbe Interaction | Scoop.it
Overview

In their struggle to survive and thrive, all living things must defend themselves from predatory attack. Microbes, in the form of parasites, bacteria, fungi, and viruses, are life's most accomplished predators. Therefore, all living things have evolved mechanisms to defend against them. Historically, biological defense systems have been classified into two broad categories—innate systems that provide nonspecific defense against invading pathogens and adaptive systems that provide long-lasting defense against attack by specific pathogens. Recently, a growing body of literature in comparative immunology has indicated that these categories may not be as distinct as was originally believed. Instead, a variety of immune mechanisms that share properties of both innate and adaptive systems have been recently elucidated. Here, we summarize five key facts about the newly appreciated shades of grey between innate and adaptive defense systems.

Via Christophe Jacquet
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