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BMC Genomics: The unique architecture and function of cellulose-interacting proteins in oomycetes revealed by genomic and structural analyses (2012)

BMC Genomics: The unique architecture and function of cellulose-interacting proteins in oomycetes revealed by genomic and structural analyses (2012) | Plant-Microbe Interaction | Scoop.it

Background - Oomycetes are fungal-like microorganisms evolutionary distinct from true fungi, belonging to the Stramenopile lineage and comprising major plant pathogens. Both oomycetes and fungi express proteins able to interact with cellulose, a major component of plant and oomycete cell walls, through the presence of carbohydrate-binding module belonging to the family 1 (CBM1). Fungal CBM1-containing proteins were implicated in cellulose degradation whereas in oomycetes, the Cellulose Binding Elicitor Lectin (CBEL), a well-characterized CBM1-protein from Phytophthora parasitica, was implicated in cell wall integrity, adhesion to cellulosic substrates and induction of plant immunity.

 

Results - To extend our knowledge on CBM1-containing proteins in oomycetes, we have conducted a comprehensive analysis on 60 fungi and 7 oomycetes genomes leading to the identification of 518 CBM1-containing proteins. In plant-interacting microorganisms, the larger number of CBM1-protein coding genes is expressed by necrotroph and hemibiotrophic pathogens, whereas a strong reduction of these genes is observed in symbionts and biotrophs. In fungi, more than 70% of CBM1-containing proteins correspond to enzymatic proteins in which CBM1 is associated with a catalytic unit involved in cellulose degradation. In oomycetes more than 90% of proteins are similar to CBEL in which CBM1 is associated with a non-catalytic PAN/Apple domain, known to interact with specific carbohydrates or proteins. Distinct Stramenopile genomes like diatoms and brown algae are devoid of CBM1 coding genes. A CBM1-PAN/Apple association 3D structural modeling was built allowing the identification of amino acid residues interacting with cellulose and suggesting the putative interaction of the PAN/Apple domain with another type of glucan. By Surface Plasmon Resonance experiments, we showed that CBEL binds to glycoproteins through galactose or N-acetyl-galactosamine motifs.

 

Conclusions - This study provides insight into the evolution and biological roles of CBM1-containing proteins from oomycetes. We show that while CBM1s from fungi and oomycetes are similar, they team up with different protein domains, either in proteins implicated in the degradation of plant cell wall components in the case of fungi or in proteins involved in adhesion to polysaccharidic substrates in the case of oomycetes. This work highlighted the unique role and evolution of CBM1 proteins in oomycete among the Stramenopile lineage.


Via Kamoun Lab @ TSL
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Rescooped by Guogen Yang from Plant Immunity And Microbial Effectors
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Elicitin-like proteins Oli-D1 and Oli-D2 from Pythium oligandrum trigger hypersensitive response in Nicotiana benthamiana and induce resistance against Botrytis cinerea in tomato

Elicitin-like proteins Oli-D1 and Oli-D2 from Pythium oligandrum trigger hypersensitive response in Nicotiana benthamiana and induce resistance against Botrytis cinerea in tomato | Plant-Microbe Interaction | Scoop.it
Summary
The biocontrol agent Pythium oligandrum and its elicitin-like proteins oligandrins have been shown to induce disease resistance in a range of plants.

Via IPM Lab
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Mashable: Chinese Researchers Create Disease-Resistant Wheat by Deleting Genes (2014)

Mashable: Chinese Researchers Create Disease-Resistant Wheat by Deleting Genes (2014) | Plant-Microbe Interaction | Scoop.it

Advanced genome-editing techniques have been used to create a strain of wheat resistant to a destructive fungal pathogen — called powdery mildew — that is a major bane to the world's top food source, according to scientists at one of China's leading centers for agricultural research.

 

To stop the mildew, researchers at the Chinese Academy of Sciences deleted genes that encode proteins that repress defenses against the mildew. The work promises to someday make wheat more resistant to the disease, which is typically controlled through the heavy use of fungicides. It also represents an important achievement in using genome editing tools to engineer food crops without inserting foreign genes — a flashpoint for opposition to genetically modified crops.

 

The gene-deletion trick is particularly tough to do in wheat because the plant has three genomes — with largely similar copies of the same genes — meaning all three must be deleted or the trait will not be changed. Using gene-editing tools known as TALENs and CRISPR, the researchers were able to do that without changing anything else or adding genes from other organisms.

 

"We now caught all three copies, and only by knocking out all three copies can we get this [mildew]-resistant phenotype," says Caixia Gao, who heads a gene-editing research group at the State Key Laboratory of Plant Cell and Chromosome Engineering at the Institute of Microbiology in Beijing.

 

A paper describing the results appears in Nature Biotechnology http://dx.doi.org/10.1038/nbt.2969.


Via Kamoun Lab @ TSL
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Interaction of the Arabidopsis GTPase RabA4c with Its Effector PMR4 Results in Complete Penetration Resistance to Powdery Mildew

Interaction of the Arabidopsis GTPase RabA4c with Its Effector PMR4 Results in Complete Penetration Resistance to Powdery Mildew | Plant-Microbe Interaction | Scoop.it

The (1,3)-β-glucan callose is a major component of cell wall thickenings in response to pathogen attack in plants. GTPases have been suggested to regulate pathogen-induced callose biosynthesis. To elucidate the regulation of callose biosynthesis in Arabidopsis thaliana, we screened microarray data and identified transcriptional upregulation of the GTPase RabA4c after biotic stress. We studied the function of RabA4c in its native and dominant negative (dn) isoform in RabA4c overexpression lines. RabA4c overexpression caused complete penetration resistance to the virulent powdery mildew Golovinomyces cichoracearum due to enhanced callose deposition at early time points of infection, which prevented fungal ingress into epidermal cells. By contrast, RabA4c(dn) overexpression did not increase callose deposition or penetration resistance. A cross of the resistant line with the pmr4 disruption mutant lacking the stress-induced callose synthase PMR4 revealed that enhanced callose deposition and penetration resistance were PMR4-dependent. In live-cell imaging, tagged RabA4c was shown to localize at the plasma membrane prior to infection, which was broken in the pmr4 disruption mutant background, with callose deposits at the site of attempted fungal penetration. Together with our interactions studies including yeast two-hybrid, pull-down, and in planta fluorescence resonance energy transfer assays, we concluded that RabA4c directly interacts with PMR4, which can be seen as an effector of this GTPase.


Via Suayib Üstün
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Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew : Nature Biotechnology : Nature Publishing Group

Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew : Nature Biotechnology : Nature Publishing Group | Plant-Microbe Interaction | Scoop.it

Sequence-specific nucleases have been applied to engineer targeted modifications in polyploid genomes1, but simultaneous modification of multiple homoeoalleles has not been reported. Here we use transcription activator–like effector nuclease (TALEN)2, 3 and clustered, regularly interspaced, short palindromic repeats (CRISPR)-Cas9 (refs. 4,5) technologies in hexaploid bread wheat to introduce targeted mutations in the three homoeoalleles that encode MILDEW-RESISTANCE LOCUS (MLO) proteins6. Genetic redundancy has prevented evaluation of whether mutation of all three MLO alleles in bread wheat might confer resistance to powdery mildew, a trait not found in natural populations7. We show that TALEN-induced mutation of all three TaMLO homoeologs in the same plant confers heritable broad-spectrum resistance to powdery mildew. We further use CRISPR-Cas9 technology to generate transgenic wheat plants that carry mutations in the TaMLO-A1 allele. We also demonstrate the feasibility of engineering targeted DNA insertion in bread wheat through nonhomologous end joining of the double-strand breaks caused by TALENs. Our findings provide a methodological framework to improve polyploid crops.


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New Phytol.: Gate control: guard cell regulation by microbial stress

New Phytol.: Gate control: guard cell regulation by microbial stress | Plant-Microbe Interaction | Scoop.it

Terrestrial plants rely on stomata, small pores in the leaf surface, for photosynthetic gas exchange and transpiration of water. The stomata, formed by a pair of guard cells, dynamically increase and decrease their volume to control the pore size in response to environmental cues. Stresses can trigger similar or opposing movements: for example, drought induces closure of stomata, whereas many pathogens exploit stomata and cause them to open to facilitate entry into plant tissues. The latter is an active process as stomatal closure is part of the plant's immune response. Stomatal research has contributed much to clarify the signalling pathways of abiotic stress, but guard cell signalling in response to microbes is a relatively new area of research. In this article, we discuss present knowledge of stomatal regulation in response to microbes and highlight common points of convergence, and differences, compared to stomatal regulation by abiotic stresses. We also expand on the mechanisms by which pathogens manipulate these processes to promote disease, for example by delivering effectors to inhibit closure or trigger opening of stomata. The study of pathogen effectors in stomatal manipulation will aid our understanding of guard cell signalling.

 

Deirdre H. McLachlan, Michaela Kopischke and Silke Robatzek

 


Via Nicolas Denancé, Jim Alfano, Francis Martin
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EMBO J: The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance (2014)

EMBO J: The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance (2014) | Plant-Microbe Interaction | Scoop.it

Plant resistance proteins of the class of nucleotide-binding and leucine-rich repeat domain proteins (NB-LRRs) are immune sensors which recognize pathogen-derived molecules termed avirulence (AVR) proteins. We show that RGA4 and RGA5, two NB-LRRs from rice, interact functionally and physically to mediate resistance to the fungal pathogen Magnaporthe oryzae and accomplish different functions in AVR recognition. RGA4 triggers an AVR-independent cell death that is repressed in the presence of RGA5 in both rice protoplasts and Nicotiana benthamiana. Upon recognition of the pathogen effector AVR-Pia by direct binding to RGA5, repression is relieved and cell death occurs. RGA4 and RGA5 form homo- and hetero-complexes and interact through their coiled-coil domains. Localization studies in rice protoplast suggest that RGA4 and RGA5 localize to the cytosol. Upon recognition of AVR-Pia, neither RGA4 nor RGA5 is re-localized to the nucleus. These results establish a model for the interaction of hetero-pairs of NB-LRRs in plants: RGA4 mediates cell death activation, while RGA5 acts as a repressor of RGA4 and as an AVR receptor.


Via Kamoun Lab @ TSL
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The interplay between central metabolism and innate immune responses -

A growing body of recent studies bring into light an important cross-talk between immune response and metabolism not only at the level of the organism as a whole, but also at the level of the individual cells. Cellular bioenergetics functions not only as a power plant to fuel up the cells, but the intermediate metabolites are shown to play an important role to modulate cellular responses. It is especially the pathways through which a cell metabolizes glucose that have been recently shown to influence both innate and adaptive immune responses, with oxidative phosphorylation used by resting or tolerant cells, while aerobic glycolysis (also termed ‘Warburg effect’) fueling activated cells. In this review we will address how the center metabolism shifts upon activation in the innate immune cells and how the intermediate metabolites modulate the function of immune cells.


Via Christophe Jacquet
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Genome Biology | Abstract | IVT-seq reveals extreme bias in RNA-sequencing

RNA-seq is a powerful technique for identifying and quantifying transcription and splicing events, both known and novel. However, given its recent development and the proliferation of library construction methods, understanding the bias it introduces is incomplete but critical to realizing its value.
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The potential for give and take in plant–microbiome relationships

The potential for give and take in plant–microbiome relationships | Plant-Microbe Interaction | Scoop.it
Mutualistic microbes present in plant-associate microbial communities provide a variety of benefits for their host, including reciprocal exchange of nutrients and/or protection from biotic and abiotic environmental stresses. Plant microbiomes have remarkably robust composition in comparison to the complex and dynamic microbial environments from which they form, suggesting finely-tuned discrimination by the plant host. Here the intersection between the plant immune system and microbiomes will be explored, both as a possible means of shaping community membership and as a consequence elicited by certain colonizing microbes. Notably, the advent of massive parallel sequencing technologies allows the investigation of these beneficial microbial functions within whole community settings, so we can now ask how engagement of the immune response influences subsequent microbial interactions. Thus, we are currently poised for future work defining how the plant immune system impacts microbiomes and consequently host health, allowing us to better understand the potential of plant productivity optimization within complex microbial surroundings.

Via Jean-Michel Ané
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Milestones in Plant Science - add your suggestions to the developing timeline hosted by ASPB

Milestones in Plant Science - add your suggestions to the developing timeline hosted by ASPB | Plant-Microbe Interaction | Scoop.it

What are the big events that shaped our understanding of plants? This site is starting to collect major milestones in the discipline, but needs your help. Send in your suggestion!


Via Mary Williams
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Activation of the Arabidopsis thaliana Immune System by Combinations of Common ACD6 Alleles

Activation of the Arabidopsis thaliana Immune System by Combinations of Common ACD6 Alleles | Plant-Microbe Interaction | Scoop.it

A fundamental question in biology is how multicellular organisms distinguish self and non-self. The ability to make this distinction allows animals and plants to detect and respond to pathogens without triggering immune reactions directed against their own cells. In plants, inappropriate self-recognition results in the autonomous activation of the immune system, causing affected individuals to grow less well. These plants also suffer from spontaneous cell death, but are at the same time more resistant to pathogens. Known causes for such autonomous activation of the immune system are hyperactive alleles of immune regulators, or epistatic interactions between immune regulators and unlinked genes. We have discovered a third class, in which the Arabidopsis thaliana immune system is activated by interactions between natural alleles at a single locus, ACCELERATED CELL DEATH 6 (ACD6). There are two main types of these interacting alleles, one of which has evolved recently by partial resurrection of a pseudogene, and each type includes multiple functional variants. Most previously studies hybrid necrosis cases involve rare alleles found in geographically unrelated populations. These two types of ACD6 alleles instead occur at low frequency throughout the range of the species, and have risen to high frequency in the Northeast of Spain, suggesting a role in local adaptation. In addition, such hybrids occur in these populations in the wild. The extensive functional variation among ACD6 alleles points to a central role of this locus in fine-tuning pathogen defenses in natural populations.


Via Christophe Jacquet
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Rescooped by Guogen Yang from Virology and Bioinformatics from Virology.ca
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Google Genomics — Google Developers

Google Genomics — Google Developers | Plant-Microbe Interaction | Scoop.it
Gives access to Google Genomics.

Explore genetic variation interactively.Compare entire cohorts in seconds with SQL-like queries. Compute transition/transversion ratios, genome-wide association, allelic frequency and more.


Via Chris Upton + helpers
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Chris Upton + helpers's curator insight, July 4, 9:42 AM

Generally...   I hate Google...

Rescooped by Guogen Yang from Plant Immunity And Microbial Effectors
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Characterization of the Largest Effector Gene Cluster of Ustilago maydis

Characterization of the Largest Effector Gene Cluster of Ustilago maydis | Plant-Microbe Interaction | Scoop.it
by Thomas Brefort, Shigeyuki Tanaka, Nina Neidig, Gunther Doehlemann, Volker Vincon, Regine Kahmann In the genome of the biotrophic plant pathogen Ustilago maydis, many of the genes coding for secreted protein effectors modulating virulence are...

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Prevalence of transcription factors in ascomycete and basidiomycete fungi

Prevalence of transcription factors in ascomycete and basidiomycete fungi | Plant-Microbe Interaction | Scoop.it
Gene regulation underlies fungal physiology and therefore is a major factor in fungal biodiversity. Analysis of genome sequences has revealed a large number of putative transcription factors in most fungal genomes. The presence of fungal orthologs for individual regulators has been analysed and appears to be highly variable with some regulators widely conserved and others showing narrow distribution. Although genome-scale transcription factor surveys have been performed before, no global study into the prevalence of specific regulators across the fungal kingdom has been presented.

Via Francis Martin
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Nature: The long-term maintenance of a resistance polymorphism through diffuse interactions (2014)

Nature: The long-term maintenance of a resistance polymorphism through diffuse interactions (2014) | Plant-Microbe Interaction | Scoop.it

Plant resistance (R) genes are a crucial component in plant defence against pathogens1. Although R genes often fail to provide durable resistance in an agricultural context, they frequently persist as long-lived balanced polymorphisms in nature2, 3, 4. Standard theory explains the maintenance of such polymorphisms through a balance of the costs and benefits of resistance and virulence in a tightly coevolving host–pathogen pair5, 6. However, many plant–pathogen interactions lack such specificity7. Whether, and how, balanced polymorphisms are maintained in diffusely interacting species8 is unknown. Here we identify a naturally interacting R gene and effector pair in Arabidopsis thaliana and its facultative plant pathogen, Pseudomonas syringae. The protein encoded by the R gene RPS5 recognizes an AvrPphB homologue (AvrPphB2) and exhibits a balanced polymorphism that has been maintained for over 2 million years (ref. 3). Consistent with the presence of an ancient balanced polymorphism, the R gene confers a benefit when plants are infected with P. syringae carrying avrPphB2 but also incurs a large cost in the absence of infection. RPS5alleles are maintained at intermediate frequencies in populations globally, suggesting ubiquitous selection for resistance. However, the presence of P. syringae carrying avrPphB is probably insufficient to explain the RPS5 polymorphism. First, avrPphB homologues occur at very low frequencies in P. syringae populations on A. thaliana. Second, AvrPphB only rarely confers a virulence benefit to P. syringae on A. thaliana. Instead, we find evidence that selection for RPS5 involves multiple non-homologous effectors and multiple pathogen species. These results and an associated model suggest that the R gene polymorphism in A. thaliana may not be maintained through a tightly coupled interaction involving a single coevolved R gene and effector pair. More likely, the stable polymorphism is maintained through complex and diffuse community-wide interactions.


Via Kamoun Lab @ TSL, Niklaus Grunwald
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Contrasting soil fungal community responses to experimental nitrogen addition using the large subunit rRNA taxonomic marker and cellobiohydrolase I functional marker

Human activities have resulted in increased nitrogen inputs into terrestrial ecosystems, but the impact of nitrogen on ecosystem function, such as nutrient cycling, will depend at least in part on the response of soil fungal communities. We examined the response of soil fungi to experimental nitrogen addition in a loblolly pine forest (North Carolina, USA) using a taxonomic marker (large subunit rDNA, LSU) and a functional marker involved in a critical step of cellulose degradation (cellobiohydrolase, cbhI) at five time points that spanned fourteen months. Sampling date had no impact on fungal community richness or composition for either gene. Based on the LSU, nitrogen addition led to increased fungal community richness, reduced relative abundance of fungi in the phylum Basidiomycota, and altered community composition; however, similar shifts were not observed with cbhI. Fungal community dissimilarity of the LSU and cbhI genes was significantly correlated in the ambient plots, but not in nitrogen-amended plots, suggesting either functional redundancy of fungi with the cbhI gene, or shifts in other functional groups in response to nitrogen addition. To determine if sequence similarity of cbhI could be predicted based on taxonomic relatedness of fungi, we conducted a phylogenetic analysis of publically-available cbhI sequences from known isolates, and found that for a subset of isolates, similar cbhI genes were found within distantly related fungal taxa. Together, these findings suggest that taxonomic shifts in the total fungal community do not necessarily result in changes in the functional diversity of fungi.


Via Francis Martin
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Arabidopsis LIP5, a Positive Regulator of Multivesicular Body Biogenesis, Is a Critical Target of Pathogen-Responsive MAPK Cascade in Plant Basal Defense

Arabidopsis LIP5, a Positive Regulator of Multivesicular Body Biogenesis, Is a Critical Target of Pathogen-Responsive MAPK Cascade in Plant Basal Defense | Plant-Microbe Interaction | Scoop.it

Multivesicular bodies (MVBs) play essential roles in many cellular processes. The MVB pathway requires reversible membrane association of the endosomal sorting complexes required for transports (ESCRTs) for sustained protein trafficking. Membrane dissociation of ESCRTs is catalyzed by the AAA ATPase SKD1, which is stimulated by LYST-INTERACTING PROTEIN 5 (LIP5). We report here that LIP5 is a target of pathogen-responsive mitogen-activated protein kinases (MPKs) and plays a critical role in plant basal resistance. Arabidopsis LIP5 interacts with MPK6 and MPK3 and is phosphorylated in vitro by activated MPK3 and MPK6 and in vivo upon expression of MPK3/6-activating NtMEK2DD and pathogen infection. Disruption of LIP5 has little effects on flg22-, salicylic acid-induced defense responses but compromises basal resistance to Pseudomonas syringae. The critical role of LIP5 in plant basal resistance is dependent on its ability to interact with SKD1. Mutation of MPK phosphorylation sites in LIP5 does not affect interaction with SKD1 but reduces the stability and compromises the ability to complement the lip5 mutant phenotypes. Using the membrane-selective FM1–43 dye and transmission electron microscopy, we demonstrated that pathogen infection increases formation of both intracellular MVBs and exosome-like paramural vesicles situated between the plasma membrane and the cell wall in a largely LIP5-dependent manner. These results indicate that the MVB pathway is positively regulated by pathogen-responsive MPK3/6 through LIP5 phosphorylation and plays a critical role in plant immune system likely through relocalization of defense-related molecules.

 

 


Via Christophe Jacquet
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Annual Review of Phytopathology: Susceptibility Genes 101: How to Be a Good Host (2014)

Annual Review of Phytopathology: Susceptibility Genes 101: How to Be a Good Host (2014) | Plant-Microbe Interaction | Scoop.it

To confer resistance against pathogens and pests in plants, typically dominant resistance genes are deployed. However, because resistance is based on recognition of a single pathogen-derived molecular pattern these narrowspectrum genes are usually readily overcome. Disease arises from a compatible interaction between plant and pathogen. Hence, altering a plant gene that critically facilitates compatibility could provide a more broad-spectrum and durable type of resistance. Here, such susceptibility (S) genes are reviewed with a focus on the mechanisms underlying loss of compatibility. We distinguish three groups of S genes acting during different stages of infection: early pathogen establishment, modulation of host defenses, and pathogen sustenance. The many examples reviewed here show that S genes have the potential to be used in resistance breeding. However, because S genes have a function other than being a compatibility factor for the pathogen, the side effects caused by their mutation demands a one-by-one assessment of their usefulness for application.


Via Kamoun Lab @ TSL
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Agrobacterium tumefaciens Deploys a Superfamily of Type VI Secretion DNase Effectors as Weapons for Interbacterial Competition In Planta: Cell Host & Microbe

Agrobacterium tumefaciens Deploys a Superfamily of Type VI Secretion DNase Effectors as Weapons for Interbacterial Competition In Planta: Cell Host & Microbe | Plant-Microbe Interaction | Scoop.it

The type VI secretion system (T6SS) is a widespread molecular weapon deployed by many Proteobacteria to target effectors/toxins into both eukaryotic and prokaryotic cells. We report that Agrobacterium tumefaciens, a soil bacterium that triggers tumorigenesis in plants, produces a family of type VI DNase effectors (Tde) that are distinct from previously known polymorphic toxins and nucleases. Tde exhibits an antibacterial DNase activity that relies on a conserved HxxD motif and can be counteracted by a cognate immunity protein, Tdi. In vitro, A. tumefaciens T6SS could kill Escherichia coli but triggered a lethal counterattack by Pseudomonas aeruginosa upon injection of the Tde toxins. However, in an in planta coinfection assay, A. tumefaciens used Tde effectors to attack both siblings cells and P. aeruginosa to ultimately gain a competitive advantage. Such acquired T6SS-dependent fitness in vivo and conservation of Tde-Tdi couples in bacteria highlights a widespread antibacterial weapon beneficial for niche colonization


Via Suayib Üstün
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Kelps feature systemic defense responses: insights into the evolution of innate immunity in multicellular eukaryotes -

Kelps feature systemic defense responses: insights into the evolution of innate immunity in multicellular eukaryotes - | Plant-Microbe Interaction | Scoop.it

Brown algae are one of the few eukaryotic lineages that have evolved complex multicellularity, together with Opisthokonts (animals, fungi) and Plantae (land plants, green and red algae). In these three lineages, biotic stresses induce similar local defense reactions. Animals and land plants also feature a systemic immune response, protecting the whole organism after an attack on one of its parts. However, the occurrence of systemic defenses has never been investigated in brown algae.We elicited selected parts of the kelp Laminaria digitata and monitored distant, nonchallenged areas of the same individual for subsequent defense reactions.A systemic reaction was detected following elicitation on a distant area, including an oxidative response, an increase in haloperoxidase activities and a stronger resistance against herbivory. Based on experiments with pharmacological inhibitors, the liberation of free fatty acids is proposed to play a key role in systemic signaling, reminiscent of what is known in land plants.This study is the first report, outside the phyla of Opisthokonts and Plantae, of an intraorganism communication leading to defense reactions. These findings indicate that systemic immunity emerged independently at least three times, as a consequence of convergent evolution in multicellular eukaryotic lineages.


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Enhanced disease resistance caused by BRI1 mutation is conserved between Brachypodium distachyon and barley (Hordeum vulgare).

Enhanced disease resistance caused by BRI1 mutation is conserved between Brachypodium distachyon and barley (Hordeum vulgare). | Plant-Microbe Interaction | Scoop.it

This study investigated the impact of brassinosteroid-insensitive 1(BRI1) mutation, the main receptor of brassinosteroids in bothBrachypodium distachyon (Bd) and barley, on disease resistance against a range of fungal pathogens of cereals exhibiting different trophic lifestyles. Results presented here show that: i) disruption ofBRI1 has pleiotropic effects on disease resistance in addition to affecting plant development. BR-signalling functions antagonistically with mechanisms of disease resistance that are effective against a broad range of cereal pathogens, ii) disruption of BRI1 results in increased disease resistance against necrotrophic and hemibiotropic pathogens that exhibit only a marginal asymptomatic phase but has no effect on biotrophic pathogens or those with a prolonged asymptomatic phase, and iii) disruption of BRI1 has a similar effect on disease resistance in Bd and barley indicating that defence mechanisms are conserved between these species. This work presents the first evidence for conservation of disease resistance mechanisms between the model species Bd and the cereal crop barley and validates Bd for undertaking model-to-crop translation studies of disease resistance.


Via Elsa Ballini, Christophe Jacquet
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Getting to the edge: protein dynamical networks as a new frontier in plant–microbe interactions

Getting to the edge: protein dynamical networks as a new frontier in plant–microbe interactions | Plant-Microbe Interaction | Scoop.it
A systems perspective on diverse phenotypes, mechanisms of infection, and responses to environmental stresses can lead to considerable advances in agriculture and medicine. A significant promise of systems biology within plants is the development of disease-resistant crop varieties, which would maximize yield output for food, clothing, building materials and biofuel production. A systems or “-omics” perspective frames the next frontier in the search for enhanced knowledge of plant network biology. The functional understanding of network structure and dynamics s is vital to expanding our knowledge of how the intercellular communication processes are executed. . This review article will systematically discuss various levels of organization of systems biology beginning with the building blocks termed “–omes” and ending with complex transcriptional and protein-protein interaction networks. We will also highlight the prevailing computational modeling approaches of biological regulatory network dynamics. The latest developments in the “-omics” approach will be reviewed and discussed to underline and highlight novel technologies and research directions in plant network biology.

Via Jean-Michel Ané
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Jean-Michel Ané's curator insight, July 10, 8:19 AM

A  bit pathogen-centric... too bad

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Tomato NAC Transcription Factor SlSRN1 Positively Regulates Defense Response against Biotic Stress but Negatively Regulates Abiotic Stress Response

Tomato NAC Transcription Factor SlSRN1 Positively Regulates Defense Response against Biotic Stress but Negatively Regulates Abiotic Stress Response | Plant-Microbe Interaction | Scoop.it

Biotic and abiotic stresses are major unfavorable factors that affect crop productivity worldwide. NAC proteins comprise a large family of transcription factors that play important roles in plant growth and development as well as in responses to biotic and abiotic stresses. In a virus-induced gene silencing-based screening to identify genes that are involved in defense response against Botrytis cinerea, we identified a tomato NAC gene SlSRN1 (Solanum lycopersicumStress-related NAC1). SlSRN1 is a plasma membrane-localized protein with transactivation activity in yeast. Expression of SlSRN1 was significantly induced by infection with B. cinerea orPseudomonas syringae pv. tomato (Pst) DC3000, leading to 6–8 folds higher than that in the mock-inoculated plants. Expression of SlSRN1 was also induced by salicylic acid, jasmonic acid and 1-amino cyclopropane-1-carboxylic acid and by drought stress. Silencing of SlSRN1resulted in increased severity of diseases caused by B. cinerea and Pst DC3000. However, silencing of SlSRN1 resulted in increased tolerance against oxidative and drought stresses. Furthermore, silencing of SlSRN1 accelerated accumulation of reactive oxygen species but attenuated expression of defense genes after infection by B. cinerea. Our results demonstrate that SlSRN1 is a positive regulator of defense response against B. cinerea and Pst DC3000 but is a negative regulator for oxidative and drought stress response in tomato.


Via Christophe Jacquet
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Rescooped by Guogen Yang from Plant Immunity And Microbial Effectors
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Arabidopsis LIP5, a Positive Regulator of Multivesicular Body Biogenesis, Is a Critical Target of Pathogen-Responsive MAPK Cascade in Plant Basal Defense

Arabidopsis LIP5, a Positive Regulator of Multivesicular Body Biogenesis, Is a Critical Target of Pathogen-Responsive MAPK Cascade in Plant Basal Defense | Plant-Microbe Interaction | Scoop.it
by Fei Wang, Yifen Shang, Baofang Fan, Jing-Quan Yu, Zhixiang Chen
Multivesicular bodies (MVBs) play essential roles in many cellular processes.

Via IPM Lab
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Rescooped by Guogen Yang from Plant Biology Teaching Resources (Higher Education)
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Robert Hooke's Micrographia (audio-annotated flipbook)

Robert Hooke's Micrographia (audio-annotated flipbook) | Plant-Microbe Interaction | Scoop.it

Here's a nice way to display a 500 year old book!


Via Mary Williams
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