Nematology
10 views | +0 today
Follow
Your new post is loading...
Your new post is loading...
Rescooped by Fenghui from Plant roots and rhizosphere
Scoop.it!

Root-knot nematodes induce pattern-triggered immunity in Arabidopsis thaliana roots - New Phytologist -

Root-knot nematodes induce pattern-triggered immunity in Arabidopsis thaliana roots -  New Phytologist - | Nematology | Scoop.it
Root-knot nematodes (RKNs; Meloidogyne spp.) are plant parasites with a broad host range causing great losses worldwide. To parasitize their hosts, RKNs establish feeding sites in roots known as giant cells. The majority of work studying plant–RKN interactions in susceptible hosts addresses establishment of the giant cells and there is limited information on the early defense responses.
Here we characterized early defense or pattern-triggered immunity (PTI) against RKNs in Arabidopsis thaliana. To address PTI, we evaluated known canonical PTI signaling mutants with RKNs and investigated the expression of PTI marker genes after RKN infection using both quantitative PCR and β-glucuronidase reporter transgenic lines.
We showed that PTI-compromised plants have enhanced susceptibility to RKNs, including the bak1-5 mutant. BAK1 is a common partner of distinct receptors of microbe- and damage-associated molecular patterns. Furthermore, our data indicated that nematode recognition leading to PTI responses involves camalexin and glucosinolate biosynthesis. While the RKN-induced glucosinolate biosynthetic pathway was BAK1-dependent, the camalexin biosynthetic pathway was only partially dependent on BAK1.
Combined, our results indicate the presence of BAK1-dependent and -independent PTI against RKNs in A. thaliana, suggesting the existence of diverse nematode recognition mechanisms.

Via Christophe Jacquet
more...
No comment yet.
Scooped by Fenghui
Scoop.it!

An Oomycete CRN Effector Reprograms Expression of Plant HSP Genes by Targeting their Promoters

An Oomycete CRN Effector Reprograms Expression of Plant  HSP  Genes by Targeting their Promoters | Nematology | Scoop.it
Author Summary Phytophthora is a genus of plant-damaging oomycetes and contains over 100 species, most of which can cause enormous economic losses on crops and environmental damage to natural ecosystems.
more...
No comment yet.
Rescooped by Fenghui from Plant roots and rhizosphere
Scoop.it!

The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes

The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes | Nematology | Scoop.it
To defend themselves against herbivores and pathogens, plants produce numerous secondary metabolites, either constitutively or de novo in response to attacks. An intriguing constitutive example is the exudate produced by certain root-cap cells that can induce a state of reversible quiescence in plant-parasitic nematodes, thereby providing protection against these antagonists. The effect of such root exudates on beneficial entomopathogenic nematodes (EPNs) remains unclear, but could potentially impair their use in pest management programmes. We therefore tested how the exudates secreted by green pea (Pisum sativum) root caps affect four commercial EPN species. The exudates induced reversible quiescence in all EPN species tested. Quiescence levels varied with the green pea cultivars tested. Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined. In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species. Our study suggests a finely tuned dual bioactivity of the exudate from green pea root caps. Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes.

Via Christophe Jacquet
more...
No comment yet.
Rescooped by Fenghui from Plant pathogens and pests
Scoop.it!

Broad Meloidogyne Resistance in Potato Based on RNA Interference of Effector Gene 16D10

Broad Meloidogyne Resistance in Potato Based on RNA Interference of Effector Gene 16D10 | Nematology | Scoop.it
Root-knot nematodes (Meloidogyne spp.) are a significant problem in potato (Solanum tuberosum) production. There is no potato cultivar with Meloidogyne resistance, even though resistance genes have been identified in wild potato species and were introgressed into breeding lines. The objectives of this study were to generate stable transgenic potato lines in a cv. Russet Burbank background that carry an RNA interference (RNAi) transgene capable of silencing the 16D10 Meloidogyne effector gene, and test for resistance against some of the most important root-knot nematode species affecting potato, i.e., M. arenaria, M. chitwoodi, M. hapla, M. incognita, and M. javanica. At 35 days after inoculation (DAI), the number of egg masses per plant was significantly reduced by 65% to 97% (P < 0.05) in the RNAi line compared to wild type and empty vector controls. The largest reduction was observed in M. hapla, whereas the smallest reduction occurred in M. javanica. Likewise, the number of eggs per plant was significantly reduced by 66% to 87% in M. arenaria and M. hapla, respectively, compared to wild type and empty vector controls (P < 0.05). Plant-mediated RNAi silencing of the 16D10 effector gene resulted in significant resistance against all of the root-knot nematode species tested, whereas RMc1(blb), the only known Meloidogyne resistance gene in potato, did not have a broad resistance effect. Silencing of 16D10 did not interfere with the attraction of M. incognita second-stage juveniles to roots, nor did it reduce root invasion.

Via Christophe Jacquet
more...
No comment yet.
Rescooped by Fenghui from Amazing Science
Scoop.it!

Researchers Discover Innate Virus-killing Power in Mammals

Researchers Discover Innate Virus-killing Power in Mammals | Nematology | Scoop.it

Findings by UC Riverside's Shou-Wei Ding could help create vaccines against deadly infections, including SARS, West Nile, dengue, Hepatitis C and influenza.

 

Viruses have been outwitting that innate protection in our cells by using proteins to suppress our virus-killing mechanism. Remove the suppressor protein from the virus, Ding’s research discovered, and the subject’s body will quickly eliminate the virus using the RNAi process, which sends out small interfering RNAs (siRNAs) to kill the disease.

 

In their research on young mice, for instance, all the subjects died when they were infected with the Nodamura virus, but when Ding’s researchers removed the suppressor protein called B2 from the virus, the infected mice began producing huge armies of the virus-attacking siRNAs and lived, unaffected by the otherwise lethal infection.

 

“Many have tried to do this, that is, find the viral siRNAs in mammals, but they could not find the key,” said Ding. “The key was our prior knowledge of the B2 protein in the Nodamura virus, a virus few people know about. Other scientists asked me, ‘What is the Nodamura virus?’ They have been studying the more well-known human viruses, but Nodamura virus infection of mice proves to be the best model.”

 

How did Ding know where to look? The China native was partly acting on a hunch that started when he was a graduate student at the Australia National University in the late 1980s. There, during a lecture, he learned that the genomes of viruses infecting plants and animals are actually very similar, even though plants and animals are very different.

 

That, and further discussions with his mentor Adrian Gibbs, an expert on molecular evolution of viruses and a fellow of the Australian Academy of Sciences, “made me think there must be a common anti-viral mechanism in plants and animals to keep their viruses similar,” he said.

 

Ding produced the first evidence for that hypothesis while working with Bob Symons in the Waite Institute in South Australia, studying cucumber mosaic virus, a devastating, aphid-carried disease that infects more than 1,000 plant species, including many important crops.

 

Using computational analytical skills learned from Gibbs, Ding discovered a small gene in the virus other scientists had overlooked. He named the gene 2b and showed that it plays an essential role in helping the virus spread within the host plant. Based on his results, and published studies on the B2 protein of Flock house virus, an insect pathogen, Ding proposed in a 1995 paper that 2b and B2 proteins act by suppressing the host’s antiviral defense.

 

Fueled by that idea, Ding moved to Singapore in 1996 to set up his own laboratory in the Institute of Molecular Agrobiology. There, in collaboration with a British group led by RNAi-expert David Baulcombe, Ding’s group discovered that the 2b protein did indeed suppress the RNAi virus-fighting properties in plants. Further, the group found that the 2b proteins of the related viruses all have the suppressor activity even though they share limited sequence similarities.

 

Ding joined the faculty at UCR in December of 2000 to test the other half of his hypothesis: does the B2 protein of Flock house virus suppress RNAi in its animal host? Although RNAi was known as a major antiviral mechanism in plants by that time, few believed it was also true in the animal kingdom, which was known to fight viral infections by many other well-defined mechanisms. Over the next five years, Ding used Flock house virus to discover that fruit flies and C. elegans nematodes have the same RNAi virus-killing properties as plants, but the B2 in the virus stop their RNAi defenses from working. Remove the B2, and the hosts produce massive amounts of siRNAs and rapidly destroy the virus.


Via Dr. Stefan Gruenwald
more...
No comment yet.
Rescooped by Fenghui from Plant pathogens and pests
Scoop.it!

The Cyst Nematode Effector Protein 10A07 Targets and Recruits Host Posttranslational Machinery to Mediate Its Nuclear Trafficking and to Promote Parasitism in Arabidopsis

The Cyst Nematode Effector Protein 10A07 Targets and Recruits Host Posttranslational Machinery to Mediate Its Nuclear Trafficking and to Promote Parasitism in Arabidopsis | Nematology | Scoop.it
Plant-parasitic cyst nematodes synthesize and secrete effector proteins that are essential for parasitism. One such protein is the 10A07 effector from the sugar beet cyst nematode, Heterodera schachtii, which is exclusively expressed in the nematode dorsal gland cell during all nematode parasitic stages. Overexpression of H. schachtii 10A07 in Arabidopsis thaliana produced a hypersusceptible phenotype in response to H. schachtii infection along with developmental changes reminiscent of auxin effects. The 10A07 protein physically associates with a plant kinase and the IAA16 transcription factor in the cytoplasm and nucleus, respectively. The interacting plant kinase (IPK) phosphorylates 10A07 at Ser-144 and Ser-231 and mediates its trafficking from the cytoplasm to the nucleus. Translocation to the nucleus is phosphorylation dependent since substitution of Ser-144 and Ser-231 by alanine resulted in exclusive cytoplasmic accumulation of 10A07. IPK and IAA16 are highly upregulated in the nematode-induced syncytium (feeding cells), and deliberate manipulations of their expression significantly alter plant susceptibility to H. schachtii in an additive fashion. An inactive variant of IPK functioned antagonistically to the wild-type IPK and caused a dominant-negative phenotype of reduced plant susceptibility. Thus, exploitation of host processes to the advantage of the parasites is one mechanism by which cyst nematodes promote parasitism of host plants.

Via Christophe Jacquet
more...
No comment yet.
Rescooped by Fenghui from Plant-Microbe Symbiosis
Scoop.it!

The application of Arabidopsis thaliana in studying tripartite interactions among plants, beneficial fungal endophytes and biotrophic plant-parasitic nematodes

The application of Arabidopsis thaliana in studying tripartite interactions among plants, beneficial fungal endophytes and biotrophic plant-parasitic nematodes | Nematology | Scoop.it
Main conclusion
The research demonstrated that Arabidopsis can be used as a model system for studying plant–nematode–endophyte tripartite interactions; thus, opening new possibilities for further characterizing the molecular mechanisms behind these interactions.
Arabidopsis has been established as an important model system for studying plant biology and plant–microbe interactions. We show that this plant can also be used for studying the tripartite interactions among plants, the root-knot nematode Meloidogyne incognita and a beneficial endophytic isolate of Fusarium oxysporum, strain Fo162. In various plant species, Fo162 can systemically reduce M. incognita infection development and fecundity. Here it is shown that Fo162 can also colonize A. thaliana roots without causing disease symptoms, thus behaving as a typical endophyte. As observed for other plants, this endophyte could not migrate from the roots into the shoots and leaves. Direct inoculation of the leaves also did not result in colonization of the plant. A significant increase in plant fresh weight, root length and average root diameter was observed, suggesting the promotion of plant growth by the endophyte. The inoculation of A. thaliana with F. oxysporum strain Fo162 also resulted in a significant reduction in the number of M. incognita juveniles infecting the roots and ultimately the number of galls produced. This was also observed in a split-root experiment, in which the endophyte and nematode were spatially separated. The usefulness of Arabidopsis opens new possibilities for further dissecting complex tripartite interactions at the molecular and biochemical level.

Via Jean-Michel Ané
more...
No comment yet.
Rescooped by Fenghui from Plant Biology Teaching Resources (Higher Education)
Scoop.it!

Molecular Mechanisms of Nematode-Nematophagous Microbe Interactions: Basis for Biological Control of Plant-Parasitic Nematodes - Annual Review of Phytopathology

Molecular Mechanisms of Nematode-Nematophagous Microbe Interactions: Basis for Biological Control of Plant-Parasitic Nematodes - Annual Review of Phytopathology | Nematology | Scoop.it

Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.


Via Steve Marek, Mary Williams
more...
Steve Marek's curator insight, May 8, 2015 11:21 AM

Nice review including summary of commercialized biocontrols.

Rescooped by Fenghui from Grain du Coteau : News ( corn maize ethanol DDG soybean soymeal wheat livestock beef pigs canadian dollar)
Scoop.it!

Are Soil Nematodes Beneficial Or Harmful?

Dec. 27, 2013 — Nematodes are often talked about in a quiet fearful voice. The image of the small microscopic worms can bring grown men to their knees. Unfortunately like many things in our world, a few “bad” apples have ruined the entire bushel. Attention has been given extensively to a small segment of the nematode population that negatively impacts crops but those nematodes are a very small percent of the nematode population. The larger percentage of the population benefit agriculture and the environment especially soil health.              

Nematodes enhance soil quality in four major areas: regulate the populations of other soil organisms, mineralize nutrients into plant-available forms, provide a food source for other soil organisms and consume disease-causing organisms.

Nematodes are considered grazers. They move through the soil profile devouring smaller organisms as well as distributing any bacteria or fungi that are on them as well as any that are in their digestive system. If the nematode population is low, they will stimulate the growth rate of prey populations. If the nematode population is high, they have the potential to have negative impact on soil health by devouring too much of their prey especially micorrhizal fungi. There are also predatory nematodes that balance the population of other nematodes

Nematodes are important nutrient mineralizers. When nematodes consume bacteria or fungi they release excess ammonium (NH4+). Bacteria and fungi both have more ammonium than what the nematode needs so the extra is released in a plant available form.

Nematodes are not the highest organism in the soil food web. Soil microarthropds and insects as well as bacteria and fungi feed on nematodes. As stated earlier, there are also predatory nematodes in the soil that consume nematodes.

A major function of soil nematodes is that they are biocontrol agents, meaning they can be used to eliminate disease causing nematodes and other organisms. This trait causes predatory nematodes to be a great resource in the battle against soil borne diseases.

For more information on nematodes and how they impact soil health, obtain a copy of the “Soil Biology Primer” published by the Soil and Water Conservation Society. For more information on how to build soil, download “Building Soil for Organic and Sustainable Farms” from Michigan State University Extension.


Via Stéphane Bisaillon
more...
No comment yet.
Scooped by Fenghui
Scoop.it!

CT scanners help researchers study wheat roots - FarmersWeekly

CT scanners help researchers study wheat roots - FarmersWeekly | Nematology | Scoop.it
CT scanners help researchers study wheat roots
FarmersWeekly
About 80% of plant problems start with the root and soil, making research into root health essential if the challenges of food security and sustainability are to be met.
more...
No comment yet.
Scooped by Fenghui
Scoop.it!

Identification of a Novel Nematotoxic Protein b...

Identification of a Novel Nematotoxic Protein b... | Nematology | Scoop.it
The dung of herbivores, the natural habitat of the model mushroom Coprinopsis cinerea, is a nutrient-rich but also very competitive environment for a saprophytic fungus. We showed previously that C.
more...
No comment yet.
Rescooped by Fenghui from Plant-parasitic nematodes
Scoop.it!

Nematode-resistant wheat can protect tomatoes — College of Agricultural and Environmental Sciences

Nematode-resistant wheat can protect tomatoes — College of Agricultural and Environmental Sciences | Nematology | Scoop.it
Nematode-resistant wheat can be a trap crop to reduce parasitic root-knot nematode numbers that damage the next rotation crop.

Via nematodes
more...
No comment yet.
Rescooped by Fenghui from Plant immunity and legume symbiosis
Scoop.it!

Two closely related members of Arabidopsis 13-lipoxygenases (13-LOXs), LOX3 and LOX4, reveal distinct functions in response to plant-parasitic nematode infection

Two closely related members of Arabidopsis 13-lipoxygenases (13-LOXs), LOX3 and LOX4, reveal distinct functions in response to plant-parasitic nematode infection | Nematology | Scoop.it

The responses of two closely related members of Arabidopsis 13-lipoxygenases (13-LOXs), LOX3 and LOX4, to infection by the sedentary nematodes root-knot nematode (Meloidogyne javanica) and cyst nematode (Heterodera schachtii) were analysed in transgenic Arabidopsis seedlings. The tissue localization of LOX3 and LOX4 gene expression using β-glucuronidase (GUS) reporter gene constructs showed local induction of LOX3 expression when second-stage juveniles reached the vascular bundle and during the early stages of plant–nematode interaction through gall and syncytia formation. Thin sections of nematode-infested knots indicated LOX3 expression in mature giant cells, and high expression in neighbouring cells and those surrounding the female body. LOX4 promoter was also activated by nematode infection, although the GUS signal weakened as infection and disease progressed. Homozygous insertion mutants lacking LOX3 were less susceptible than wild-type plants to root-knot nematode infection, as reflected by a decrease in female counts. Conversely, deficiency in LOX4 function led to a marked increase in females and egg mass number and in the female to male ratio of M. javanica and H. schachtii, respectively. The susceptibility of lox4 mutants was accompanied by increased expression of allene oxide synthase, allene oxide cyclase and ethylene-responsive transcription factor 4, and the accumulation of jasmonic acid, measured in the roots of lox4 mutants. This response was not found in lox3 mutants. Taken together, our results reveal that LOX4 and LOX3 interfere differentially with distinct metabolic and signalling pathways, and that LOX4 plays a major role in controlling plant defence against nematode infection.


Via Christophe Jacquet
more...
No comment yet.
Rescooped by Fenghui from Plants and Microbes
Scoop.it!

J Experimental Botany: Special Issue: Mechanisms of Plant–Insect Interactions (2015)

J Experimental Botany: Special Issue: Mechanisms of Plant–Insect Interactions (2015) | Nematology | Scoop.it

PREFACE

Robert D. Hancock, Saskia Hogenhout, and Christine H. Foyer
Mechanisms of plant–insect interaction


REVIEW ARTICLES

Select this article
Mark C. Mescher and Consuelo M. De Moraes
Role of plant sensory perception in plant–animal interactions

Simon A. Zebelo and Massimo E. Maffei
Role of early signalling events in plant–insect interactions

Joe Louis and Jyoti Shah
Plant defence against aphids: the PAD4 signalling nexus

Toby J. A. Bruce
Interplay between insects and plants: dynamic and complex interactions that have coevolved over millions of years but act in milliseconds

Akiko Sugio, Géraldine Dubreuil, David Giron, and Jean-Christophe Simon
Plant–insect interactions under bacterial influence: ecological implications and underlying mechanisms

Pankaj Barah and Atle M. Bones
Multidimensional approaches for studying plant defence against insects: from ecology to omics and synthetic biology

Christine H. Foyer, Susan R. Verrall, and Robert D. Hancock
Systematic analysis of phloem-feeding insect-induced transcriptional reprogramming in Arabidopsis highlights common features and reveals distinct responses to specialist and generalist insects

M. O. Harris, T. L. Friesen, S. S. Xu, M. S. Chen, D. Giron, and J. J. Stuart
Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress

Alexandra C. U. Furch, Aart J. E. van Bel, and Torsten Will
Aphid salivary proteases are capable of degrading sieve-tube proteins


RESEARCH PAPERS

A. D. Coleman, R. H. M. Wouters, S. T. Mugford, and S. A. Hogenhout
Persistence and transgenerational effect of plant-mediated RNAi in aphids

Godshen R. Pallipparambil, Ronald J. Sayler, Jeffrey P. Shapiro, Jean M. G. Thomas, Timothy J. Kring, and Fiona L. Goggin
Mi-1.2, an R gene for aphid resistance in tomato, has direct negative effects on a zoophytophagous biocontrol agent, Orius insidiosus

Chengjun Wu, Carlos A. Avila, and Fiona L. Goggin
The ethylene response factor Pti5 contributes to potato aphid resistance in tomato independent of ethylene signalling

Mariam Betsiashvili, Kevin R. Ahern, and Georg Jander
Additive effects of two quantitative trait loci that confer Rhopalosiphum maidis (corn leaf aphid) resistance in maize inbred line Mo17

Ishita Ahuja, Nicole Marie van Dam, Per Winge, Marianne Trælnes, Aysel Heydarova, Jens Rohloff, Mette Langaas, and Atle Magnar Bones
Plant defence responses in oilseed rape MINELESS plants after attack by the cabbage moth Mamestra brassicae

Jian Yan, Alexander E. Lipka, Eric A. Schmelz, Edward S. Buckler, and Georg Jander
Accumulation of 5-hydroxynorvaline in maize (Zea mays) leaves is induced by insect feeding and abiotic stress

Ivan Hiltpold, Geoffrey Jaffuel, and Ted C. J. Turlings
The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes

James M. W. Ryalls, Ben D. Moore, Markus Riegler, Andrew N. Gherlenda, and Scott N. Johnson
Amino acid-mediated impacts of elevated carbon dioxide and simulated root herbivory on aphids are neutralized by increased air temperatures


Via Kamoun Lab @ TSL
more...
No comment yet.
Rescooped by Fenghui from Plants and Microbes
Scoop.it!

Mol Plant Pathol: A Meloidogyne incognita effector is imported into the nucleus and exhibits transcriptional activation activity in planta (2014)

Mol Plant Pathol: A Meloidogyne incognita effector is imported into the nucleus and exhibits transcriptional activation activity in planta (2014) | Nematology | Scoop.it

Root-knot nematodes are sedentary biotrophic endoparasites that maintain a complex interaction with their host plants. Nematode effector proteins are synthesized in the oesophageal glands of nematodes and secreted into plant tissue through a needle-like stylet. Effectors characterized to date have been shown to mediate processes essential for nematode pathogenesis. To gain an insight into their site of action and putative function, the subcellular localization of 13 previously isolated Meloidogyne incognita effectors was determined. Translational fusions were created between effectors and EGFP-GUS (enhanced green fluorescent protein-β-glucuronidase) reporter genes, which were transiently expressed in tobacco leaf cells. The majority of effectors localized to the cytoplasm, with one effector, 7H08, imported into the nuclei of plant cells. Deletion analysis revealed that the nuclear localization of 7H08 was mediated by two novel independent nuclear localization domains. As a result of the nuclear localization of the effector, 7H08 was tested for the ability to activate gene transcription. 7H08 was found to activate the expression of reporter genes in both yeast and plant systems. This is the first report of a plant-parasitic nematode effector with transcriptional activation activity.


Via Kamoun Lab @ TSL
more...
No comment yet.
Rescooped by Fenghui from Plants and Microbes
Scoop.it!

Current Opinion in Plant Biology: Evolutionarily conserved CLE peptide signaling in plant development, symbiosis, and parasitism (2013)

Current Opinion in Plant Biology: Evolutionarily conserved CLE peptide signaling in plant development, symbiosis, and parasitism (2013) | Nematology | Scoop.it

Small polypeptides are widely used as signaling molecules in cell-to-cell communication in animals and plants. The CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) gene family is composed of numerous genes that contain conserved CLE domains in various plant species and plant-parasitic nematodes. Here, we review recent progress in our understanding of CLE signaling during stem cell maintenance in Arabidopsis and grasses. We also summarize the roles of CLE signaling in the legume-Rhizobium symbiosis and infection by plant-parasitic nematodes. CLE signaling is important for diverse aspects of cell-to-cell signaling and long-distance communication, which are critical for survival, and the basic components of the CLE signaling pathway are evolutionarily conserved in both plants and animals.


Via Kamoun Lab @ TSL
more...
No comment yet.
Rescooped by Fenghui from Plants and Microbes
Scoop.it!

PLOS Pathogens: Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors (2014)

PLOS Pathogens: Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors (2014) | Nematology | Scoop.it

Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize venom allergen-like proteins to suppress the activation of defenses by immunogenic breakdown products in damaged host tissue.


Via Kamoun Lab @ TSL
more...
No comment yet.
Rescooped by Fenghui from Plants and Microbes
Scoop.it!

A Plant Immune Receptor Detects Pathogen Effectors that Target WRKY Transcription Factors: Cell

A Plant Immune Receptor Detects Pathogen Effectors that Target WRKY Transcription Factors: Cell | Nematology | Scoop.it

Defense against pathogens in multicellular eukaryotes depends on intracellular immune receptors, yet surveillance by these receptors is poorly understood. Several plant nucleotide-binding, leucine-rich repeat (NB-LRR) immune receptors carry fusions with other protein domains. The Arabidopsis RRS1-R NB-LRR protein carries a C-terminal WRKY DNA binding domain and forms a receptor complex with RPS4, another NB-LRR protein. This complex detects the bacterial effectors AvrRps4 or PopP2 and then activates defense. Both bacterial proteins interact with the RRS1 WRKY domain, and PopP2 acetylates lysines to block DNA binding. PopP2 and AvrRps4 interact with other WRKY domain-containing proteins, suggesting these effectors interfere with WRKY transcription factor-dependent defense, and RPS4/RRS1 has integrated a “decoy” domain that enables detection of effectors that target WRKY proteins. We propose that NB-LRR receptor pairs, one member of which carries an additional protein domain, enable perception of pathogen effectors whose function is to target that domain.


Via Freddy Monteiro, Christophe Jacquet, DrDrPlant, Kamoun Lab @ TSL
more...
Freddy Monteiro's curator insight, May 21, 2015 12:50 PM

See also the back-to-back paper:

A Receptor Pair with an Integrated Decoy Converts Pathogen Disabling of Transcription Factors to Immunity http://www.cell.com/cell/abstract/S0092-8674%2815%2900442-0

 

See also the preview:

Treasure Your Exceptions: Unusual Domains in Immune Receptors Reveal Host Virulence Targets http://www.cell.com/cell/abstract/S0092-8674%2815%2900566-8

Rescooped by Fenghui from Amazing Science
Scoop.it!

Glowing Worms Illuminate Roots of Behavior in Animals

Glowing Worms Illuminate Roots of Behavior in Animals | Nematology | Scoop.it

Researchers develop novel method to image worm brain activity and screen early stage compounds aimed at treating autism and anxiety.

 

A research team at Worcester Polytechnic Institute (WPI) and The Rockefeller University in New York has developed a novel system to image brain activity in multiple awake and unconstrained worms. The technology, which makes it possible to study the genetics and neural circuitry associated with animal behavior, can also be used as a high-throughput screening tool for drug development targeting autism, anxiety, depression, schizophrenia, and other brain disorders.

 

The team details their technology and early results in the paper "High-throughput imaging of neuronal activity in Caenorhabditis elegans," published on-line in advance of print by the journal Proceedings of the National Academy of Sciences .

 

"One of our major objectives is to understand the neural signals that direct behavior—how sensory information is processed through a network of neurons leading to specific decisions and responses," said Dirk Albrecht, PhD, assistant professor of biomedical engineering at WPI and senior author of the paper. Albrecht led the research team both at WPI and at Rockefeller, where he served previously as a postdoctoral researcher in the lab of Cori Bargmann, PhD, a Howard Hughes Medical Institute Investigator and a co-author of the new paper.

 

To study neuronal activity, Albrecht’s lab uses the tiny worm Caenorhabditis elegans (C. elegans), a nematode found in many environments around the world. A typical adult C. elegans is just 1 millimeter long and has 969 cells, of which 302 are neurons. Despite its small size, the worm is a complex organism able to do all of the things animals must do to survive. It can move, eat, mate, and process environmental cues that help it forage for food or react to threats. As a bonus for researchers, C.elegans is transparent. By using various imaging technologies, including optical microscopes, one can literally see into the worm and watch physiological processes in real time.

 

In addition to watching the head neurons light up as they picked up odor cues, the new system can trace signaling through "interneurons." These are pathways that connect external sensors to the rest of the network (the "worm brain") and send signals to muscle cells that adjust the worm's movement based on the cues. Numerous brain disorders in people are believed to arise when neural networks malfunction. In some cases the malfunction is dramatic overreaction to a routine stimulus, while in others it is a lack of appropriate reactions to important cues. Since C. elegans and humans share many of the same genes, discovering genetic causes for differing neuronal responses in worms could be applicable to human physiology. Experimental compounds designed to modulate the action of nerve cells and neuronal networks could be tested first on worms using Albrecht’s new system. The compounds would be infused in the worm arena, along with other stimuli, and the reaction of the worms’ nervous systems could be imaged and analyzed.


Via Dr. Stefan Gruenwald
more...
No comment yet.