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New Phytologist: The dispensable chromosome of Leptosphaeria maculans shelters an effector gene conferring avirulence towards Brassica rapa (2013)

New Phytologist: The dispensable chromosome of Leptosphaeria maculans shelters an effector gene conferring avirulence towards Brassica rapa (2013) | Plant-Microbe Interaction | Scoop.it

Phytopathogenic fungi frequently contain dispensable chromosomes, some of which contribute to host range or pathogenicity. In Leptosphaeria maculans, the stem canker agent of oilseed rape (Brassica napus), the minichromosome was previously suggested to be dispensable, without evidence for any role in pathogenicity.

Using genetic and genomic approaches, we investigated the inheritance and molecular determinant of an L. maculans–Brassica rapa incompatible interaction.

Single gene control of the resistance was found, while all markers located on the L. maculans minichromosome, absent in the virulent parental isolate, co-segregated with the avirulent phenotype. Only one candidate avirulence gene was identified on the minichromosome, validated by complementation experiments and termed AvrLm11. The minichromosome was frequently lost following meiosis, but the frequency of isolates lacking it remained stable in field populations sampled at a 10-yr time interval, despite a yearly sexual stage in the L. maculans life cycle.

This work led to the cloning of a new ‘lost in the middle of nowhere’ avirulence gene of L. maculans, interacting with a B. rapa resistance gene termed Rlm11 and introgressed into B. napus. It demonstrated the dispensability of the L. maculans minichromosome and suggested that its loss generates a fitness deficit.


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An improved high throughput sequencing method for studying oomycete communities

An improved high throughput sequencing method for studying oomycete communities | Plant-Microbe Interaction | Scoop.it

Oomycete community pyrosequencing improved by increasing PCR annealing temperature.

High proportion of oomycete reads from soil DNA and from symptomatic carrot tissue

A wide diversity of oomycetes in soil and symptomatic carrot tissues was observed.


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DNA sequencing using polymerase substrate-binding kinetics

DNA sequencing using polymerase substrate-binding kinetics | Plant-Microbe Interaction | Scoop.it
Article
Next-generation sequencing technologies vary in performance, which is often measured by metrics such as sequencing speed, accuracy and read length.

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A Truncated NLR Protein, TIR-NBS2, Is Required for Activated Defense Responses in the exo70B1 Mutant

A Truncated NLR Protein, TIR-NBS2, Is Required for Activated Defense Responses in the exo70B1 Mutant | Plant-Microbe Interaction | Scoop.it

Abstract

 

During exocytosis, the evolutionarily conserved exocyst complex tethers Golgi-derived vesicles to the target plasma membrane, a critical function for secretory pathways. Here we show that exo70B1 loss-of-function mutants express activated defense responses upon infection and express enhanced resistance to fungal, oomycete and bacterial pathogens. In a screen for mutants that suppress exo70B1 resistance, we identified nine alleles of TIR-NBS2 (TN2), suggesting that loss-of-function of EXO70B1 leads to activation of this nucleotide binding domain and leucine-rich repeat-containing (NLR)-like disease resistance protein. This NLR-like protein is atypical because it lacks the LRR domain common in typical NLR receptors. In addition, we show that TN2 interacts with EXO70B1 in yeast and in planta. Our study thus provides a link between the exocyst complex and the function of a ‘TIR-NBS only’ immune receptor like protein. Our data are consistent with a speculative model wherein pathogen effectors could evolve to target EXO70B1 to manipulate plant secretion machinery. TN2 could monitor EXO70B1 integrity as part of an immune receptor complex.

Author Summary

Secretory pathways play an important role in the plant immune response by delivering antimicrobial compounds and metabolites to the site of infection. The evolutionarily conserved exocyst complex is involved in exocytosis, the final step in the secretory pathway. We showed that loss of the function of EXO70B1, a subunit of exocyst complex, results in activated defense responses, and enhanced resistance to a range of pathogens. We found that EXO70B1 associates with the SNARE complex protein SNAP33, which is involved in focal secretion of defense-related proteins. Enhanced disease resistance and cell death in the exo70B1 mutant are dependent on TIR-NBS2 (TN2), an atypical intracellular immune receptor-like protein that lacks leucine-rich repeats. TN2 physically associates with EXO70B1, and TN2 transcripts accumulate at much higher levels in the exo70B1 mutant. These data are consistent with a model where activation of a receptor pathway containing TIR-NBS2 is responsible for activated defense responses and cell death in exo70B1. Our data further suggest that this, and possibly other, exocyst components could be targets of effectors that are guarded by immune receptors.

 

 


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Rescooped by Guogen Yang from Plant Biology Teaching Resources (Higher Education)
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Secrets Of Nature - Peas And Cues (1930-1939) - YouTube

Pro Patria films presentation. Produced by British Instructional Films Ltd. Seed of a pea plant shown growing through time lapse photography. 

Wow, amazing for its time, and still pretty fascinating.

Watch out for heartbreak at 8:30!

(Thanks to International Society for Seed Science  http://seedscisoc.org/ ; for sharing)


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Single and combined colonization of Sclerotinia sclerotiorum sclerotia by the fungal mycoparasites Coniothyrium minitans and Microsphaeropsis ochracea

Single and combined colonization of Sclerotinia sclerotiorum sclerotia by the fungal mycoparasites Coniothyrium minitans and Microsphaeropsis ochracea | Plant-Microbe Interaction | Scoop.it

The potential enhancement of mycoparasitic efficacy of C. minitans and M. ochracea through concomitant colonization of S. sclerotiorum sclerotia was investigated, encouraged by the observation that the two mycoparasites did not exhibit any mutual antagonism in dual culture assays. Simultaneous application of both mycoparasites increased sclerotia mortality in a temperature range from 16 to 26°C compared to single application, indicating a predominantly additive interaction. With increasing temperature the efficacy of M. ochracea decreased while this was not observed for C. minitans. Degradation of sclerotia by C. minitans proceeded slightly faster than with M. ochracea. Simultaneous colonization of sclerotia was studied on the histopathological level with mycoparasite strains transformed via Agrobacterium tumefaciens mediated transformation (ATMT) with reporter genes encoding for DsRed and GFP fluorescing proteins. Sclerotia colonization followed by fluorescence microscopy revealed effective penetration of the sclerotial rind, growth and formation of pycnidia in the cortex and medulla by both antagonists, resulting in complete degradation of sclerotia within 25 days after single inoculation. Upon simultaneous inoculation, both antagonists concomitantly colonized the sclerotial tissue and independently formed pycnidia in the sclerotial medulla and on the sclerotial rind, demonstrating their ability to co-colonize the same host fungus. Although the individual growth of the two mycoparasites in dual inoculations was slightly delayed, the sclerotia degrading effects were additive, suggesting a complementary antagonistic interaction. The combined application of two different species of mycoparasites cooperating on the same host fungus and differing in temperature requirements may be advantageous for making biocontrol applications in the field less sensitive to varying environmental and host conditions.

 

 


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Rescooped by Guogen Yang from Rice Blast
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APIP10 Is a Novel E3 Ligase That Functionally Connects the Fungal Effector AvrPiz-t to Its NLR Receptor Piz-t in Rice

We previously isolated the avirulence effector AvrPiz-t from the fungal pathogen Magnaporthe oryzae and its cognate NLR receptor Piz-t in Oryza sativa (rice). Here, we report that AvrPiz-t targets the rice E3 ligase APIP10 (AvrPiz-t Interacting Proteins 10) for degradation but in return APIP10 ubiquitinates AvrPiz-t that causes its degradation in planta. Silencing ofAPIP10 in the non-Piz-t background leads to a significant reduction of flg22-induced ROS generation, suppression of defense-related gene expression and enhanced susceptibility against M. oryzae. Interestingly, silencing of APIP10 in the Piz-t background causes severe cell death, significant accumulation of Piz-t and enhanced resistance to M. oryzae, suggesting that APIP10 is a negative regulator of Piz-t.  In addition, we show that APIP10 promotes degradation of Piz-t via the 26S proteasome system. Furthermore, we demonstrate that AvrPi-z-t stabilizes Piz-t during M. oryzae infection. Together our results show that APIP10 is a novel host E3 ligase that functionally connects the fungal effector AvrPiz-t to its NLR receptor Piz-t in rice.


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Cell wall traits as potential resources to improve resistance of durum wheat against Fusarium graminearum

Cell wall traits as potential resources to improve resistance of durum wheat against Fusarium graminearum | Plant-Microbe Interaction | Scoop.it
Background

Fusarium graminearum, one of the causal agents of Fusarium Head Blight (FHB, scab), leads to severe losses in grain yield and quality due to the production of mycotoxins which are harmful to human and livestock. Different traits for FHB resistance in wheat were identified for common wheat (Triticum aestivum L.) while the sources of FHB resistance in durum wheat (Triticum turgidum ssp. Durum), one of the cereals most susceptible to F. graminearum infection, have not been found. New lines of evidence indicate that content and composition of cell wall polymers affect the susceptibility of the wall to degrading enzymes produced by pathogens during infection and can play a role in the outcome of host-pathogen interactions. The objective of our research is to identify potential cell wall biochemical traits linked to Fusariosis resistance to be transferred from a resistant common wheat to a susceptible durum wheat line.
Results

A detailed analysis of cell wall composition in spikes isolated from a highly resistant common wheat accession “02-5B-318”, a breeding line derived from the FHB-resistant Chinese cv. Sumai-3 and a high susceptible durum wheat cv. Saragolla was performed. Significant differences in lignin monolignols composition, arabinoxylan (AX) substitutions and pectin methylesterification were found between resistant and susceptible plants. We isolated and characterized a pectin methylesterase gene WheatPME1, which we found being down regulated in the FHB-resistant line and induced by fungal infection in the susceptible wheat.
Conclusions

Our results indicate cell wall traits differing between the FHB sensitive and resistant wheat genotypes, possibly related to FHB-resistance, and identify the line 02-5B-318R as a potential resource of such traits. Evidence suggests that WheatPME1 is involved in wheat response to F. graminearum.

Via Christophe Jacquet
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Understanding and managing soil biodiversity: a major challenge in agroecology

Understanding and managing soil biodiversity: a major challenge in agroecology | Plant-Microbe Interaction | Scoop.it
Soils are living environments in which particularly abundant and diverse microbiome and fauna are evolving. The resulting biological functioning has a direct impact not only on soil fertility but also on a series of ecosystems services. Thus, microbial communities are involved in geochemical cycles in which microbial enzymes catalyse the different steps. Modulation of the corresponding activities is essential as these affect plant growth and environmental quality. In general, biodiversity affects both the productivity and stability of agroecosystems. It is therefore of paramount importance to take soil biodiversity and biological functioning into account when designing cropping systems and evaluating their impacts. The progress achieved in soil microbiology in recent years now makes it possible to propose analyses of soil biology, as has been feasible for many years for soil physicochemistry. These analyses obviously require the use of standardized procedures for soil sampling, measuring the abundance and diversity of the microbial communities, as well as the identification of bioindicators. Similarly, referential systems need to be established to interpret these analyses and diagnose the biological status of soils, and, more especially, to determine whether the obtained values are within the range of variations normal for a given soil type and land use. Great progress to standardize such procedures and establish referential systems has been achieved during large-scale research programmes carried out to characterize biodiversity on national and European scales. These diagnostic elements need to be accompanied by recommendations. The aim of ongoing research is thus to propose aids for decision-making, based on the results of biological analyses, so attempts can be made to monitor and manage biodiversity to satisfy soil fertility requirements and ensure the ecosystem services expected of soils.

Via Jean-Michel Ané
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The Plant Cell Reviews Dynamic Aspects of Plant Hormone Signaling and Crosstalk

The Plant Cell Reviews Dynamic Aspects of Plant Hormone Signaling and Crosstalk | Plant-Microbe Interaction | Scoop.it

The Roles of ROS and ABA in Systemic Acquired Acclimation

Ron Mittler and Eduardo Blumwald

Plant Cell 2015 tpc.114.133090; First Published on January 20, 2015; doi:10.1105/tpc.114.133090 OPEN

http://www.plantcell.org/content/early/2015/01/20/tpc.114.133090.abstract

 

SCFTIR1/AFB-Based Auxin Perception: Mechanism and Role in Plant Growth and Development

Mohammad Salehin, Rammyani Bagchi, and Mark Estelle

Plant Cell 2015 tpc.114.133744; First Published on January 20, 2015; doi:10.1105/tpc.114.133744

http://www.plantcell.org/content/early/2015/01/20/tpc.114.133744.abstract

 

The PB1 Domain in Auxin Response Factor and Aux/IAA Proteins: A Versatile Protein Interaction Module in the Auxin Response

Tom J. Guilfoyle

Plant Cell 2015 tpc.114.132753; First Published on January 20, 2015; doi:10.1105/tpc.114.132753 OPEN

http://www.plantcell.org/content/early/2015/01/20/tpc.114.132753.abstract

 

PIN-Dependent Auxin Transport: Action, Regulation, and Evolution

Maciek Adamowski and Jiří Friml

Plant Cell 2015 tpc.114.134874; First Published on January 20, 2015; doi:10.1105/tpc.114.134874

http://www.plantcell.org/content/early/2015/01/20/tpc.114.134874.abstract

 

The Yin-Yang of Hormones: Cytokinin and Auxin Interactions in Plant Development

G. Eric Schaller, Anthony Bishopp, and Joseph J. Kieber

Plant Cell 2015 tpc.114.133595; First Published on January 20, 2015; doi:10.1105/tpc.114.133595

http://www.plantcell.org/content/early/2015/01/20/tpc.114.133595.abstract


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Rescooped by Guogen Yang from Virology and Bioinformatics from Virology.ca
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Antiviral immunity Dual attack by RIG-I - Nature.com

Antiviral immunity Dual attack by RIG-I
Nature.com
A recent study in Immunity describes a novel antiviral role for the cytosolic sensor RIG-I. Sato et al.

Via Gilbert Faure au nom de l'ASSIM, Kenzibit
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Gilbert Faure au nom de l'ASSIM's curator insight, January 19, 2:13 PM

A recent study in Immunity describes a novel antiviral role for the cytosolic sensor RIG-I. Sato et al. show that RIG-I not only induces an interferon (IFN) response during hepatitis B virus (HBV) infection, but also directly suppresses viral replication by blocking the binding of the HBV polymerase to the pre-genomic RNA (pgRNA) of the virus…

 http://www.scoop.it/t/immunology?q=rig

 

from WIKIPEDIA

RIG-I (retinoic acid-inducible gene 1) is a RIG-I-like receptor dsRNA helicase enzyme that is encoded (in humans) by the DDX58 gene. RIG-I is part of the RIG-I-like receptor family, which also includes MDA5 and LGP2, and functions as a pattern recognition receptor that is a sensor for viruses such as influenza A, Sendai virus, and flavivirus, however RIG-I provides no immunity to DNA viruses or retroviruses. RIG-I typically recognizes short (< 4000nt) 5′ triphosphate uncapped double stranded or single stranded RNA.[1][2][3] RIG-I and MDA5 are involved in activating MAVS and triggering an antiviral response.[4] RIG-I is also able to detect non-self 5′-triphosphorylated dsRNA transcribed from AT-rich dsDNA by DNA-dependent RNA polymerase III (Pol III). For many viruses, effective RIG-I-mediated antiviral responses are dependent on functionally active LGP2.[5]

 







Rescooped by Guogen Yang from Plant Immunity And Microbial Effectors
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The focus on bibliometrics makes papers less useful

Forcing research to fit the mould of high-impact journals weakens it. Hiring decisions should be based on merit, not impact factor, says Reinhard Werner.

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Fast and sensitive protein alignment using DIAMOND : Nature Methods : Nature Publishing Group

Fast and sensitive protein alignment using DIAMOND : Nature Methods : Nature Publishing Group | Plant-Microbe Interaction | Scoop.it
The open-source DIAMOND software provides protein alignment that is 20,000 times faster on short reads than BLASTX at similar sensitivity, for rapid analysis of large metagenomics data sets on a desktop computer.

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The Arabidopsis Transcription Factor BES1 Is a Direct Substrate of MPK6 and Regulates Immunity

Pathogen-associated molecular patterns (PAMPs) are recognized by plant pattern-recognition receptors (PRRs) to activate PAMP-triggered immunity (PTI). Mitogen-activated protein kinases (MAPKs), as well as other cytoplasmic kinases, integrate upstream immune signals, and in turn dissect PTI signaling via different substrates to regulate defense responses. However, only a few direct substrates of these signaling kinases have been identified. Here we show that PAMP perception enhances phosphorylation of BES1 (BRI1-EMS suppressor 1), a transcription factor involved in brassinosteroid (BR) signaling pathway, through pathogen-induced MAPKs in Arabidopsis. BES1 interacts with MPK6 (MAP kinase 6), and is phosphorylated by MPK6. bes1 loss-of-function mutants display compromised resistance to bacterial pathogen Pseudomonas syringae pv. tomato DC3000. BES1SSAA (BES1 S286A/S137A double mutation) impairs PAMP-induced phosphorylation and fails to restore bacterial resistance in bes1 mutant, indicating a positive role of BES1 phosphorylation in plant immunity. BES1 is phosphorylated by glycogen synthase kinase-3 (GSK3)-like kinase BIN2 (BR insensitive 2), a negative regulator of BR signaling. BR perception inhibits BIN2 activity, allowing dephosphorylation of BES1 to regulate plant development. However, BES1SSAA does not affect BR-mediated plant growth, suggesting differential residue requirements for the modulation of BES1 phosphorylation in PTI and BR signaling. Our study identifies BES1 as a novel direct substrate of MPK6 in PTI signaling. This finding reveals MAPK-mediated BES1 phosphorylation as another BES1 modulation mechanism in plant cell signaling, in addition to GSK3-like kinase-mediated BES1 phosphorylation and F box protein-mediated BES1 degradation.

Via Suayib Üstün
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Building the interaction interfaces: host responses upon infection with microorganisms

Building the interaction interfaces: host responses upon infection with microorganisms | Plant-Microbe Interaction | Scoop.it

Highlights•

Pathogens and symbionts trigger common host responses.

These biotic interactions affect plant developmental and physiological processes.

Interactions between plants and microorganisms may shape plant community.

Research fields of plant symbiosis and plant immunity were relatively ignorant with each other until a little while ago. Recently, however, increasing intercommunications between those two fields have begun to provide novel aspects and knowledge for understanding relationships between plants and microorganisms. Here, we review recent reports on plant–microbe interactions, focusing on the infection processes, in order to elucidate plant cellular responses that are triggered by both symbionts and pathogens. Highlighting the core elements of host responses over biotic interactions will provide insights into general mechanisms of plant–microbe interactions.


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Rescooped by Guogen Yang from How microbes emerge
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Population genetic structure of the ectomycorrhizal fungus Laccaria sp. A resembles that of its host tree Nothofagus cunninghamii

Population genetic structure of the ectomycorrhizal fungus Laccaria sp. A resembles that of its host tree Nothofagus cunninghamii | Plant-Microbe Interaction | Scoop.it
The ectomycorrhizal fungus Laccaria sp. A is restricted to temperate rainforest of southeast Australia, associated with its host tree Nothofagus cunninghamii. Eight mitochondrial microsatellite markers were used to investigate the population genetic structure of L. sp. A across its distribution in Tasmania and Victoria. The highest allelic diversity was found in Tasmania, which appeared to contain a panmictic population, whereas the more fragmented Victorian populations were characterized by low allelic diversity and differentiation between east and west. There is evidence of glacial refugia in the west and the northeast of Tasmania, and in Victoria in the Otway Ranges and Central Highlands, with postglacial migration into the Strzelecki Ranges. Narrow host-specificity may have contributed to the presence of population structure in this fungus. Allelic diversity patterns in L. sp. A are largely congruent with diversity patterns already established in populations of its host, N. cunninghamii.

Via Francis Martin, Niklaus Grunwald
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Rescooped by Guogen Yang from MycorWeb Plant-Microbe Interactions
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New world-class scientific collaboration to use genomics to combat devastating crop rusts

New world-class scientific collaboration to use genomics to combat devastating crop rusts | Plant-Microbe Interaction | Scoop.it

The newly formed Norwich Rust Group aims to develop durable resistance in crops. Exploiting advances in genomics, scientists will investigate how parasitic rust fungi invade and feed off plants. They will also use these new techniques to locate genes in some varieties of crops which are able to resist invasion. There are more than 7,000 species of rust fungi, some of which are among agriculture’s most devastating pathogens, causing diseases such as Wheat Stem Rust, Wheat Yellow (Stripe) Rust, Asian Soybean Rust and Coffee Rust.


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Mechanisms by which the infection of sclerotinia sclerotiorum (lib) de bary affects the photosynthetic performance in tobacco leaves

Mechanisms by which the infection of sclerotinia sclerotiorum (lib) de bary affects the photosynthetic performance in tobacco leaves | Plant-Microbe Interaction | Scoop.it

Background Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen which causes disease in a wide range of plants. An observed decrease in photosynthetic performance is the primary reason for the reduction of crop yield induced by S. sclerotiorum. The H2C2O4 is the main pathogenic material secreted by S. sclerotiorum, but the effects of H2C2O4 acidity and the C2O4 2? ion on photosynthetic performance remain unknown.Results S. sclerotiorum infection significantly decreased photosynthetic O2 evolution and the maximum quantum yield of photosystem II (Fv/Fm) in tobacco leaves under high-light. H2C2O4 (the main pathogenic material secreted by S. sclerotiorum) with pH?4.0 also significantly decreased photosynthetic performance. However, treatment with H3PO4 and HCl at the same pH as H2C2O4 caused much less decrease in photosynthetic performance than H2C2O4 did. These results verify that the acidity of the H2C2O4 secreted by S. sclerotiorum was only partially responsible for the observed decreases in photosynthesis. Treatment with 40?mM K2C2O4 decreased Fv/Fm by about 70% of the levels observed under 40?mM H2C2O4, which further demonstrates that C2O4 2? was the primary factor that impaired photosynthetic performance during S. sclerotiorum infection. K2C2O4 treatment did not further decrease photosynthetic performance when D1 protein synthesis was fully inhibited, indicating that C2O4 2? inhibited PSII by repressing D1 protein synthesis. It was observed that K2C2O4 treatment inhibited the rate of RuBP regeneration and carboxylation efficiency. In the presence of a carbon assimilation inhibitor, K2C2O4 2 treatment did not further decrease photosynthetic performance, which infers that C2O4 2? inhibited PSII activity partly by repressing the carbon assimilation. In addition, it was showed that C2O4 2? treatment inhibited the PSII activity but not the PSI activity.ConclusionsThis study demonstrated that the damage to the photosynthetic apparatus induced by S. sclerotiorum is not only caused by the acidity of H2C2O4, but also by C2O4 2? which plays a much more important role in damaging the photosynthetic apparatus. C2O4 2? inhibits PSII activity, as well as the rate of RuBP regeneration and carboxylation efficiency, leading to the over production of reactive oxygen species (ROS). By inhibiting the synthesis of D1, ROS may further accelerate PSII photoinhibition.


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Nuclear trafficking, histone cleavage and induction of apoptosis by the meningococcal App and MspA autotransporters

Nuclear trafficking, histone cleavage and induction of apoptosis by the meningococcal App and MspA autotransporters | Plant-Microbe Interaction | Scoop.it
Summary
Neisseria meningitidis, a major cause of bacterial meningitis and septicemia, secretes multiple virulence factors including the adhesion and penetration protein (App) and meningococcal serine protease A (MspA).

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Frontiers | Optimizing experimental procedures for quantitative evaluation of crop plant performance in high throughput phenotyping systems | Crop Science and Horticulture

Frontiers | Optimizing experimental procedures for quantitative evaluation of crop plant performance in high throughput phenotyping systems | Crop Science and Horticulture | Plant-Microbe Interaction | Scoop.it
Detailed and standardized protocols for plant cultivation in environmentally controlled conditions are an essential prerequisite to conduct reproducible experiments with precisely defined treatments. Setting up appropriate and well defined experimental procedures is thus crucial for the generation of solid evidence and indispensable for successful plant research. Non-invasive and high throughput (HT) phenotyping technologies offer the opportunity to monitor and quantify performance dynamics of several hundreds of plants at a time. Compared to small scale plant cultivations, HT systems have much higher demands, from a conceptual and a logistic point of view, on experimental design, as well as the actual plant cultivation conditions, and the image analysis and statistical methods for data evaluation. Furthermore, cultivation conditions need to be designed that elicit plant performance characteristics corresponding to those under natural conditions. This manuscript describes critical steps in the optimization of procedures for HT plant phenotyping systems. Starting with the model plant Arabidopsis, HT-compatible methods were tested, and optimized with regard to growth substrate, soil coverage, watering regime, experimental design (considering environmental inhomogeneities) in automated plant cultivation and imaging systems. As revealed by metabolite profiling, plant movement did not affect the plants' physiological status. Based on these results, procedures for maize HT cultivation and monitoring were established. Variation of maize vegetative growth in the HT phenotyping system did match well with that observed in the field. The presented results outline important issues to be considered in the design of HT phenotyping experiments for model and crop plants. It thereby provides guidelines for the setup of HT experimental procedures, which are required for the generation of reliable and reproducible data of phenotypic variation for a broad range of applications.

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Rescooped by Guogen Yang from Plant-Microbe Symbioses
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AHL-priming functions via oxylipin and salicylic acid

AHL-priming functions via oxylipin and salicylic acid | Plant-Microbe Interaction | Scoop.it
Collaborative action between the host plant and associated bacteria is crucial for the establishment of an efficient interaction. In bacteria, the synchronized behavior of a population is often achieved by a density-dependent communication called quorum sensing. This behavior is based on signaling molecules, which influence bacterial gene expression. N-acyl homoserine lactones (AHLs) are such molecules in many Gram-negative bacteria. Moreover, some AHLs are responsible for the beneficial effect of bacteria on plants, for example the long chain N-3-oxo-tetradecanoyl-L-homoserine lactone (oxo-C14-HSL) can prime Arabidopsis and barley plants for an enhanced defense. This AHL-induced resistance phenomenon, named AHL-priming, was observed in several independent laboratories during the last two decades. Very recently, the mechanism of priming with oxo-C14-HSL was shown to depend on an oxylipin and salicylic acid (SA). SA is a key element in plant defense, it accumulates during different plant resistance responses and is the base of systemic acquired resistance. In addition, SA itself can prime plants for an enhanced resistance against pathogen attack. On the other side, oxylipins, including jasmonic acid (JA) and related metabolites, are lipid-derived signaling compounds. Especially the oxidized fatty acid derivative cis-OPDA, which is the precursor of JA, is a newly described player in plant defense. Unlike the antagonistic effect of SA and JA in plant–microbe interactions, the recently described pathway functions through a synergistic effect of oxylipins and SA, and is independent of the JA signaling cascade. Interestingly, the oxo-C14-HSL-induced oxylipin/SA signaling pathway induces stomata defense responses and cell wall strengthening thus prevents pathogen invasion. In this review, we summarize the findings on AHL-priming and the related signaling cascade. In addition, we discuss the potential of AHL-induced resistance in new strategies of plant protection.

Via Jean-Michel Ané
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Unexpectedly low nitrogen acquisition and absence of root architecture adaptation to nitrate supply in a Medicago truncatula highly branched root mutant

Unexpectedly low nitrogen acquisition and absence of root architecture adaptation to nitrate supply in a Medicago truncatula highly branched root mutant | Plant-Microbe Interaction | Scoop.it
To complement N2 fixation through symbiosis, legumes can efficiently acquire soil mineral N through adapted root architecture. However, root architecture adaptation to mineral N availability has been little studied in legumes. Therefore, this study investigated the effect of nitrate availability on root architecture in Medicago truncatula and assessed the N-uptake potential of a new highly branched root mutant, TR185. The effects of varying nitrate supply on both root architecture and N uptake were characterized in the mutant and in the wild type. Surprisingly, the root architecture of the mutant was not modified by variation in nitrate supply. Moreover, despite its highly branched root architecture, TR185 had a permanently N-starved phenotype. A transcriptome analysis was performed to identify genes differentially expressed between the two genotypes. This analysis revealed differential responses related to the nitrate acquisition pathway and confirmed that N starvation occurred in TR185. Changes in amino acid content and expression of genes involved in the phenylpropanoid pathway were associated with differences in root architecture between the mutant and the wild type.

Via Christophe Jacquet, Jean-Michel Ané
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Rescooped by Guogen Yang from Plant Biology Teaching Resources (Higher Education)
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ISME J: Exploring functional contexts of symbiotic sustain within lichen-associated bacteria by comparative omics

ISME J: Exploring functional contexts of symbiotic sustain within lichen-associated bacteria by comparative omics | Plant-Microbe Interaction | Scoop.it

Symbioses represent a frequent and successful lifestyle on earth and lichens are one of their classic examples. Recently, bacterial communities were identified as stable, specific and structurally integrated partners of the lichen symbiosis, but their role has remained largely elusive in comparison to the well-known functions of the fungal and algal partners. We have explored the metabolic potentials of the microbiome using the lung lichen Lobaria pulmonaria as the model. Metagenomic and proteomic data were comparatively assessed and visualized by Voronoi treemaps. The study was complemented with molecular, microscopic and physiological assays. We have found that more than 800 bacterial species have the ability to contribute multiple aspects to the symbiotic system, including essential functions such as (i) nutrient supply, especially nitrogen, phosphorous and sulfur, (ii) resistance against biotic stress factors (that is, pathogen defense), (iii) resistance against abiotic factors, (iv) support of photosynthesis by provision of vitamin B12, (v) fungal and algal growth support by provision of hormones, (vi) detoxification of metabolites, and (vii) degradation of older parts of the lichen thallus. Our findings showed the potential of lichen-associated bacteria to interact with the fungal as well as algal partner to support health, growth and fitness of their hosts. We developed a model of the symbiosis depicting the functional multi-player network of the participants, and argue that the strategy of functional diversification in lichens supports the longevity and persistence of lichens under extreme and changing ecological conditions.


Via Stéphane Hacquard, Mary Williams
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Rescooped by Guogen Yang from Plant Immunity And Microbial Effectors
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Phytomonas : Trypanosomatids Adapted to Plant Environments

Phytomonas : Trypanosomatids Adapted to Plant Environments | Plant-Microbe Interaction | Scoop.it
Over 100 years after trypanosomatids were first discovered in plant tissues, Phytomonas parasites have now been isolated across the globe from members of 24 different plant families. Most identified species have not been associated with any plant pathology and to date only two species are definitively known to cause plant disease. These diseases (wilt of palm and coffee phloem necrosis) are problematic in areas of South America where they threaten the economies of developing countries. In con

Via IPM Lab
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Rescooped by Guogen Yang from TAL effector science
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TALEN-mediated genome engineering to generate targeted mice - Chromosome Res.

TALEN-mediated genome engineering to generate targeted mice - Chromosome Res. | Plant-Microbe Interaction | Scoop.it

Sommer et al, 2015

Genetic mouse models are critical for biomedical research to understand gene function and pathophysiology. In the last years, the generation of genetic mouse models has been revolutionized by the emergence of transcription activator-like effector nucleases (TALENs). TALENs are programmable, sequence-specific DNA-binding proteins fused to a non-specific endonuclease domain used as powerful tools for site-specific induction of DNA double-strand breaks. These result in disruption of the gene product of the targeted locus by mutations induced during repair by error-prone non-homologous end-joining. Alternatively, these DNA double-strand breaks can be exploited to integrate a user-defined sequence by homologous recombination if an appropriate repair plasmid is provided. In this review, we highlight the major technological improvements for genome editing in murine oocytes which have been achieved using TALENs, discuss current limitations of the technology, suggest strategies to broadly apply TALENs, and describe possible future directions to facilitate gene editing in murine oocytes.


Via dromius
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Rescooped by Guogen Yang from Plant immunity and legume symbiosis
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Jasmonates Induce Both Defense Responses and Communication in Monocotyledonous and Dicotyledonous Plants

Jasmonates Induce Both Defense Responses and Communication in Monocotyledonous and Dicotyledonous Plants | Plant-Microbe Interaction | Scoop.it
Jasmonic acid (JA) and its derivatives (jasmonates, JAs) are phytohormones with essential roles in plant defense against pathogenesis and herbivorous arthropods. Both the up- and down-regulation of defense responses are dependent on signaling pathways mediated by JAs as well as other stress hormones (e.g. salicylic acid), generally those involving the transcriptional and post-transcriptional regulation of transcription factors via protein modification and epigenetic regulation. In addition to the typical model plant Arabidopsis (a dicotyledon), advances in genetics research have made rice a model monocot in which innovative pest control traits can be introduced and whose JA signaling pathway can be studied. In this review, we introduce the dynamic functions of JAs in plant defense strategy using defensive substances (e.g. indole alkaloids and terpenoid phytoalexins) and airborne signals (e.g. green leaf volatiles and volatile terpenes) in response to biotrophic and necrotrophic pathogens as well as above-ground and below-ground herbivores. We then discuss the important issue of how the mutualism of herbivorous arthropods with viruses or bacteria can cause cross-talk between JA and other phytohormones to counter the defense systems.

Via Christophe Jacquet
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