MicroRNAs in plant-pathogen interactions: Small RNAs big impact
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MicroRNAs in plant-pathogen interactions: Small RNAs big impact
MicroRNAs are non-coding small RNAs that regulate the post-transcriptional gene expression by binding or cleaving the complementary sequences on target messenger RNA, usually resulting in inhibition of the translation of target gene or gene silencing. MicroRNA-mediated gene silencing is a conserved regulatory mechanism in almost all eukaryotic organisms and has been reported to control plant-pathogen interaction. However, little is known about the microRNA-regulated gene(s) expression during plant-pathogen interaction. This blog has been created with the aim of keeping a database of papers and up to date information on microRNAs and their role in plant diseases. Readers are encouraged to post their brilliant comments on the papers or topics of their interest. I hope their valuable comments and exchange of ideas will help keep this blog live!
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Rescooped by Lalit Kharbikar from Plants and Microbes
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Current Opinion in Microbiology: Of guards, decoys, baits and traps: pathogen perception in plants by type III effector sensors (2015)

Current Opinion in Microbiology: Of guards, decoys, baits and traps: pathogen perception in plants by type III effector sensors (2015) | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

• Type III effectors perturb host cellular components to promote pathogen virulence.

• Perturbations of type III effector sensors induce effector-triggered immunity.

• We provide a current, characteristic overview of plant type III effector sensors.

 

Effector-triggered immunity (ETI) is conferred by dominant plant resistance (R) genes, which encode predominantly nucleotide-binding and leucine-rich repeat domain proteins (NLRs), against cognate microbial avirulence (Avr) genes, which include bacterial type III secreted effectors (T3Es). The ‘guard model’ describes the mechanism of T3E perception by plants, whereby NLRs monitor host proteins (‘sensors’) for T3E-induced perturbations. This model has provided a molecular framework to understand T3E perception and has rationalized how plants can use a limited number of NLRs (∼160 in Arabidopsis) to contend with a potentially limitless number of evolving effectors. In this review we provide a characteristic overview of plant T3E sensors and discuss how these sensors convey the presence of T3Es to NLR proteins to activate ETI.


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Rakesh Yashroy's curator insight, November 28, 2015 8:09 AM

Type 3 secretion system of gram negative microbes affects both plants and animals. How proteins are threaded through a  rather narrow injectisome and with what efficiency remains a riddle. T3SS proteins are also known to be secreted via outer membrane vesicles. A fusion of these two systems may provide answer to efficiency of bacteria-host interactions @ http://www.labome.org/research/Membrane-vesicle-trafficking-in-prokaryotes-molecular-biomechanics-of-biogenesis-of-outer-membrane-v.html

Rescooped by Lalit Kharbikar from Publications
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Cellular Microbiology: Rust fungal effectors mimic host transit peptides to translocate into chloroplasts (2015)

Cellular Microbiology: Rust fungal effectors mimic host transit peptides to translocate into chloroplasts (2015) | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

Parasite effector proteins target various host cell compartments to alter host processes and promote infection. How effectors cross membrane-rich interfaces to reach these compartments is a major question in effector biology. Growing evidence suggests that effectors use molecular mimicry to subvert host cell machinery for protein sorting. We recently identified CTP1 (chloroplast-targeted protein 1), a candidate effector from the poplar leaf rust fungus Melampsora larici-populina that carries a predicted transit peptide and accumulates in chloroplasts and mitochondria. Here, we show that the CTP1 transit peptide is necessary and sufficient for accumulation in the stroma of chloroplasts. CTP1 is part of a Melampsora-specific family of polymorphic secreted proteins. Two members of that family, CTP2 and CTP3, also translocate in chloroplasts in a N-terminal signal-dependent manner. CTP1, CTP2 and CTP3 are cleaved when they accumulate in chloroplasts, while they remain intact when they do not translocate into chloroplasts. Our findings reveal that fungi have evolved effector proteins that mimic plant-specific sorting signals to traffic within plant cells.


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miR-23a, miR-24 and miR-27a protect differentiating ESCs from BMP4-... - PubMed - NCBI

Cell Death Differ. 2014 Dec 5. doi: 10.1038/cdd.2014.198. [Epub ahead of print]
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MicroRNAs Still Do Not Support an Evolutionary "Tree of Life"

MicroRNAs Still Do Not Support an Evolutionary "Tree of Life" | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
kevin.j.peterson.preferred_0.jpeg As we reported here and here in 2012, biologist Kevin Peterson at Dartmouth (pictured at right) sent shock waves through the Darwin community when he studied microRNAs and found they ...
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Molecular Profiling of the Phytophthora plurivora Secretome: A Step towards Understanding the Cross-Talk between Plant Pathogenic Oomycetes and Their Hosts

Molecular Profiling of the Phytophthora plurivora Secretome: A Step towards Understanding the Cross-Talk between Plant Pathogenic Oomycetes and Their Hosts | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
PLOS ONE: an inclusive, peer-reviewed, open-access resource from the PUBLIC LIBRARY OF SCIENCE. Reports of well-performed scientific studies from all disciplines freely available to the whole world.

Via Christophe Jacquet
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Soil Temperature Determines the Reaction of Olive Cultivars to Verticillium dahliae Pathotypes

Soil Temperature Determines the Reaction of Olive Cultivars to Verticillium dahliae Pathotypes | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
PLOS ONE: an inclusive, peer-reviewed, open-access resource from the PUBLIC LIBRARY OF SCIENCE. Reports of well-performed scientific studies from all disciplines freely available to the whole world.

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The Xanthomonas campestris effector protein XopDXcc8004 triggers plant disease tolerance by targeting DELLA proteins - Tan - 2014 - New Phytologist - Wiley Online Library

The Xanthomonas campestris effector protein XopDXcc8004 triggers plant disease tolerance by targeting DELLA proteins - Tan - 2014 - New Phytologist - Wiley Online Library | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
Plants protect themselves from the harmful effects of pathogens by resistance and tolerance. Disease resistance, which eliminates pathogens, can be modulated by bacterial type III effectors. Little is known about whether disease tolerance, which sustains host fitness with a given pathogen burden, is regulated by effectors.
Here, we examined the effects of the Xanthomonas effector protein XopDXcc8004 on plant disease defenses by constructing knockout and complemented Xanthomonas strains, and performing inoculation studies in radish (Raphanus sativus L. var. radiculus XiaoJinZhong) and Arabidopsis plants.
XopDXcc8004 suppresses disease symptoms without changing bacterial titers in infected leaves. In Arabidopsis, XopDXcc8004 delays the hormone gibberellin (GA)-mediated degradation of RGA (repressor of ga1-3), one of five DELLA proteins that repress GA signaling and promote plant tolerance under biotic and abiotic stresses. The ERF-associated amphiphilic repression (EAR) motif-containing region of XopDXcc8004 interacts with the DELLA domain of RGA and might interfere with the GA-induced binding of GID1, a GA receptor, to RGA.
The EAR motif was found to be present in a number of plant transcriptional regulators. Thus, our data suggest that bacterial pathogens might have evolved effectors, which probably mimic host components, to initiate disease tolerance and enhance their survival.

Via Christophe Jacquet
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Reduced susceptibility to Fusarium head blight in Brachypodium distachyon through priming with the Fusarium mycotoxin deoxynivalenol - Blümke - 2014 - Molecular Plant Pathology - Wiley Online Library

Reduced susceptibility to Fusarium head blight in Brachypodium distachyon through priming with the Fusarium mycotoxin deoxynivalenol - Blümke - 2014 - Molecular Plant Pathology - Wiley Online Library | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

The fungal cereal pathogen Fusarium graminearum produces deoxynivalenol (DON) during infection. The mycotoxin DON is associated with Fusarium head blight (FHB), a disease that can cause vast grain losses. Whilst investigating the suitability of Brachypodium distachyon as a model for spreading resistance to F. graminearum, we unexpectedly discovered that DON pretreatment of spikelets could reduce susceptibility to FHB in this model grass. We started to analyse the cell wall changes in spikelets after infection with F. graminearum wild-type and defined mutants: the DON-deficient Δtri5 mutant and the DON-producing lipase disruption mutant Δfgl1, both infecting only directly inoculated florets, and the mitogen-activated protein (MAP) kinase disruption mutant Δgpmk1, with strongly decreased virulence but intact DON production. At 14 days post-inoculation, the glucose amounts in the non-cellulosic cell wall fraction were only increased in spikelets infected with the DON-producing strains wild-type, Δfgl1 and Δgpmk1. Hence, we tested for DON-induced cell wall changes in B. distachyon, which were most prominent at DON concentrations ranging from 1 to 100 ppb. To test the involvement of DON in defence priming, we pretreated spikelets with DON at a concentration of 1 ppm prior to F. graminearum wild-type infection, which significantly reduced FHB disease symptoms. The analysis of cell wall composition and plant defence-related gene expression after DON pretreatment and fungal infection suggested that DON-induced priming of the spikelet tissue contributed to the reduced susceptibility to FHB.


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Perturbation of host ubiquitin systems by plant pathogen/pest effector proteins - Banfield - Cellular Microbiology - Wiley Online Library

Perturbation of host ubiquitin systems by plant pathogen/pest effector proteins - Banfield - Cellular Microbiology - Wiley Online Library | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
Microbial pathogens and pests of animals and plants secrete effector proteins into host cells, altering cellular physiology to the benefit of the invading parasite. Research in the past decade has delivered significant new insights into the molecular mechanisms of how these effector proteins function, with a particular focus on modulation of host immunity-related pathways. One host system that has emerged as a common target of effectors is the ubiquitination system in which substrate proteins are post-translationally modified by covalent conjugation with the small protein ubiquitin. This modification, typically via isopeptide bond formation through a lysine side-chain of ubiquitin, can result in target degradation, re-localisation, altered activity or affect protein-protein interactions. In this review I focus primarily on how effector proteins from bacterial and filamentous pathogens of plants and pests perturb host ubiquitination pathways that ultimately include the 26S proteasome. The activities of these effectors, in how they affect ubiquitin pathways in plants, reveals how pathogens have evolved to identify and exploit weaknesses in this system that deliver increased pathogen fitness.

Via Suayib Üstün, Christophe Jacquet
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Silicon-mediated resistance of Arabidopsis against powdery mildew involves mechanisms other than the SA-dependent defense pathway - Vivancos - Molecular Plant Pathology - Wiley Online Library

Silicon-mediated resistance of Arabidopsis against powdery mildew involves mechanisms other than the SA-dependent defense pathway - Vivancos - Molecular Plant Pathology - Wiley Online Library | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

Upon absorption by plants, silicon (Si) will offer protection against many fungal pathogens including powdery mildews. The mechanisms by which Si exerts its prophylactic role remain enigmatic although a prevailing hypothesis suggests that Si positively influences priming. Attempts to decipher Si properties have been limited to plants able to absorb Si, which excludes the model plant Arabidopsis because it lacks Si influx transporters. In this work, we were able to engineer Arabidopsis plants with a Si transporter from wheat (TaLsi1) and exploit mutants (pad4 and sid2) deficient in salicylic acid (SA)-dependent defense responses to study their phenotypic response and changes in defense expression against Golovinomyces cichoracearum (Gc) following a Si treatment. Our results showed that TaLsi1 plants contained significantly more Si and were significantly more resistant to Gc infection than control plants when treated with Si, the first such demonstration in a plant transformed with a heterologous Si transporter. The resistant plants accumulated higher levels of SA and expressed higher levels of transcripts encoding defense genes, thus suggesting a role for Si in the process. However, TaLsi1 pad4 and TaLsi1 sid2 plants were also more resistant to Gc than pad4 and sid2 plants following Si treatment. Analysis of the resistant phenotypes revealed a significantly reduced production of SA and expression of defense genes comparable to susceptible controls. These results indicate that Si contributes to Arabidopsis-defense priming following pathogen infection but highlight that Si will confer protection even when priming is altered. We conclude that Si-mediated protection involves mechanisms other than SA-dependent defense responses.


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Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker - Shi - 2014 ...

Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker - Shi - 2014 ... | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, ‘Nagami’ kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6 h and up to 72 h after Xflg22 treatment. At the other end of the spectrum, highly susceptible ‘Duncan’ grapefruit showed no induction of the same defence genes, even 120 h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (XccΔfliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker.


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Biotic Interactions Overrule Plant Responses to Climate, Depending on the Species' Biogeography

Biotic Interactions Overrule Plant Responses to Climate, Depending on the Species' Biogeography | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
PLOS ONE: an inclusive, peer-reviewed, open-access resource from the PUBLIC LIBRARY OF SCIENCE. Reports of well-performed scientific studies from all disciplines freely available to the whole world.

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Auxin-mediated relationships between apple plants and root inhabiting fungi: impact on root pathogens and potentialities of growth-promoting populations - Manici - 2014 - Plant Pathology - Wiley On...

Auxin-mediated relationships between apple plants and root inhabiting fungi: impact on root pathogens and potentialities of growth-promoting populations - Manici - 2014 - Plant Pathology - Wiley On... | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

This study aimed to elucidate the relationship between plant hosts and root-colonizing fungi recovered from apple orchard soils that had been replanted over multiple generations. Functional relationships of three groups of filamentous fungi (Ceratobasidium sp., Cylindrocarpon-like group and Fusarium acuminatum) with apple rootstocks were evaluated in plant growth bioassays. The Cylindrocarpon-like group and Ceratobasidium sp. showed a relationship with the host plant varying from pathogenic to commensal through to mutualistic for the latter group, while that of F. acuminatum tended to be mutualistic. Seven fungal isolates of each group, which induced the highest plant growth in bioassays, were evaluated for auxin (IAA) and gibberellin (GA3 and GA4) production in culture filtrate. All isolates of F. acuminatum as well as most of those of the Ceratobasidium sp. and Cylindrocarpon-like groups produced IAA in culture filtrate. IAA production was evaluated for additional isolates of endophytic fungal species from fruit tree orchards and the functionality of IAA was confirmed by growing in vitro micropropagated plantlets of apple rootstock on MS medium supplemented with fungal culture filtrate. Findings from this study may explain the difficulty in defining the precise role of diverse root-colonizing fungal populations in replant disease aetiology of fruit tree orchards. However, the results demonstrate the presence of a positive and widely available biotic component of the orchard soil biology that may be exploited for the benefit of tree growth and production.


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Rescooped by Lalit Kharbikar from Publications from The Sainsbury Laboratory
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Cell Host & Microbe: Fungal Sex Receptors Recalibrated to Detect Host Plants (2015)

Cell Host & Microbe: Fungal Sex Receptors Recalibrated to Detect Host Plants (2015) | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

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The Sainsbury Lab's curator insight, December 10, 2015 9:47 AM

Secreted peroxidases are well-known components of damage-induced defense responses in plants. A recent study in Nature ( Turrà et al., 2015) has revealed that these enzymes can inadvertently serve as reporters of wounded sites and constitute an “Achilles heel,” allowing adapted pathogens to track and enter host tissue.

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Small regulatory RNAs and the fine-tuning of plant–bacteria interactions - Harfouche - 2014 - New Phytologist - Wiley Online Library

Small regulatory RNAs and the fine-tuning of plant–bacteria interactions - Harfouche - 2014 - New Phytologist - Wiley Online Library | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
Small regulatory RNAs (sRNAs) play a key role in many physiological and adaptive responses in bacteria. Faced with rapidly changing environments, it is more advantageous for bacteria to use sRNA-mediated responses than regulation by protein transcriptional factors, as sRNAs act at the post-transcriptional level and require less energy and time for their synthesis and turnover. The use of RNA deep sequencing has provided hundreds of sRNA candidates in different bacterial species that interact with plants. Here, we review the most recent results for the involvement of bacterial sRNAs in beneficial as well as deleterious plant–bacteria interactions. We describe the current view for the role of sRNAs, which are suggested to improve competition for both niches and resources in plant-interacting bacteria. These sRNAs also help plant-associated bacteria individually adapt to the rapidly changing conditions to which they are exposed, during different stages of this interaction.

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BMC Genomics | Abstract | RNA-Seq profile of flavescence doree phytoplasma in grapevine

The phytoplasma-borne disease flavescence doree is still a threat to European viticulture, despite mandatory control measures and prophylaxis against the leafhopper vector.

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Dissection of miRNA pathways using Arabidopsis mesophyll protoplasts

Dissection of miRNA pathways using Arabidopsis mesophyll protoplasts | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
microRNAs (miRNAs) control gene expression mostly post-transcriptionally by guiding transcript cleavage and/or translational repression of complementary mRNA targets, thereby regulating developmental processes and stress responses. Despite the remarkable expansion of the field, the mechanisms underlying miRNA activity are not fully understood. In this paper, we describe a transient expression system in Arabidopsis mesophyll protoplasts that is highly amenable for the dissection of miRNA pathways. We show that by transiently overexpressing primary miRNAs and target mimics, we can manipulate miRNA levels and consequently impact on their targets. Furthermore, we developed a set of luciferase-based sensors for quantifying miRNA activity that respond specifically to both endogenous and overexpressed miRNAs and target mimics. We demonstrate that these miRNA sensors can be used to test the impact of putative components of the miRNA pathway on miRNA activity, as well as the impact of specific mutations, either by overexpression or by the use of protoplasts from the corresponding mutants. We further show that our miRNA sensors can be used for investigating the effect of chemicals on miRNA activity. Our cell-based transient expression system is fast and easy to set up and generates quantitative results, being a powerful tool for assaying miRNA activity in vivo.

Via Biswapriya Biswavas Misra
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Biswapriya Biswavas Misra's curator insight, November 5, 2014 10:24 PM

microRNAs (miRNAs) control gene expression mostly post-transcriptionally by guiding transcript cleavage and/or translational repression of complementary mRNA targets, thereby regulating developmental processes and stress responses. Despite the remarkable expansion of the field, the mechanisms underlying miRNA activity are not fully understood. In this paper, we describe a transient expression system in Arabidopsis mesophyll protoplasts that is highly amenable for the dissection of miRNA pathways. We show that by transiently overexpressing primary miRNAs and target mimics, we can manipulate miRNA levels and consequently impact on their targets. Furthermore, we developed a set of luciferase-based sensors for quantifying miRNA activity that respond specifically to both endogenous and overexpressed miRNAs and target mimics. We demonstrate that these miRNA sensors can be used to test the impact of putative components of the miRNA pathway on miRNA activity, as well as the impact of specific mutations, either by overexpression or by the use of protoplasts from the corresponding mutants. We further show that our miRNA sensors can be used for investigating the effect of chemicals on miRNA activity. Our cell-based transient expression system is fast and easy to set up and generates quantitative results, being a powerful tool for assaying miRNA activity in vivo.

Rescooped by Lalit Kharbikar from Plant roots and rhizosphere
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Auxin-mediated relationships between apple plants and root inhabiting fungi: Impact on root pathogens and potentialities of growth-promoting populations - Manici - Plant Pathology - Wiley Online Li...

Auxin-mediated relationships between apple plants and root inhabiting fungi: Impact on root pathogens and potentialities of growth-promoting populations - Manici - Plant Pathology - Wiley Online Li... | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

Keywords:binucleate Rhizoctonia sp;Cylindrocarpon-like fungi;Fusarium acuminatum ;Fusarium spp;rooting induction;Indole-3-acetic acid (IAA);replant disease

Abstract

Studies were aimed at elucidating the relationship between plant hosts and root-colonizing fungi recovered in multi-generation replanted apple orchard soils. Functional relationships of three groups of filamentous fungi (Ceratobasidium sp., Cylindrocaropon-like group and Fusarium acuminatum) with apple rootstocks were evaluated in plant growth bioassays. Cylindrocaropon-like group and Ceratobasidium sp. showed a relationship with the host plant varying from pathogenic to commensal through to mutualistic for the latter group, while that of F. acuminatum tended to be mutualistic. Seven fungal isolates of each group which induced the highest plant growth in bioassays were evaluated for auxin (IAA) and gibberellins (GA3 and GA4) produced in culture filtrate. All isolates of F. acuminatum as well as most of those of the Ceratobasidium sp. and Cylindrocarpon like groups produced IAA in culture filtrate. IAA production was evaluated on additional isolates of endophytic fungal species isolated in fruit tree orchards and IAA-based functionality was confirmed by growing in vitro micropropagated plantlets of apple rootstock on MS medium supplemented with fungal culture filtrate. Findings from this study may explain the difficulty in defining the precise role of diverse root-colonizing fungal populations in replant disease etiology of fruit tree orchards. Alternatively, the results demonstrate the presence of a positive and widely available biotic component of the orchard soil biology which may be exploited for the benefit of tree growth and production.

 

 


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Expression Profiling during Arabidopsis/Downy Mildew Interaction Reveals a Highly-Expressed Effector That Attenuates Responses to Salicylic Acid

Expression Profiling during Arabidopsis/Downy Mildew Interaction Reveals a Highly-Expressed Effector That Attenuates Responses to Salicylic Acid | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
From molecules to physiology

Via Kamoun Lab @ TSL, Christophe Jacquet
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Elicitation of hypersensitive responses in Nicotiana glutinosa by the suppressor of RNA silencing protein P0 from poleroviruses - Wang - 2014 - Molecular Plant Pathology - Wiley Online Library

Elicitation of hypersensitive responses in Nicotiana glutinosa by the suppressor of RNA silencing protein P0 from poleroviruses - Wang - 2014 - Molecular Plant Pathology - Wiley Online Library | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
Plant disease resistance (R) proteins that confer resistance to viruses recognize viral gene products with diverse functions, including viral suppressors of RNA silencing (VSRs). The P0 protein from poleroviruses is a VSR that targets the ARGONAUTE1 (AGO1) protein for degradation, thereby disrupting RNA silencing and antiviral defences. Here, we report resistance against poleroviruses in Nicotiana glutinosa directed against Turnip yellows virus (TuYV) and Potato leafroll virus (PLRV). The P0 proteins from TuYV (P0Tu), PLRV (P0PL) and Cucurbit aphid-borne yellows virus (P0CA) were found to elicit a hypersensitive response (HR) in N. glutinosa accession TW59, whereas other accessions recognized P0PL only. Genetic analysis showed that recognition of P0Tu by a resistance gene designated RPO1 (Resistance to POleroviruses 1) is inherited as a dominant allele. Expression of P0 from a Potato virus X (PVX) expression vector transferred recognition to the recombinant virus on plants expressing RPO1, supporting P0 as the unique Polerovirus factor eliciting resistance. The induction of HR required a functional P0 protein, as P0Tu mutants with substitutions in the F-box motif that abolished VSR activity were unable to elicit HR. We surmised that the broad P0 recognition seen in TW59 and the requirement for the F-box protein motif could indicate detection of P0-induced AGO1 degradation and disruption of RNA silencing; however, other viral silencing suppressors, including the PVX P25 that also causes AGO1 degradation, failed to elicit HR in N. glutinosa. Investigation of P0 elicitation of RPO1 could provide insight into P0 activities within the cell that trigger resistance.

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BMC Genomics | Full text | Transposable element-assisted evolution and adaptation to host plant within the Leptosphaeria maculans-Leptosphaeria biglobosa species complex of fungal pathogens

Many plant-pathogenic fungi have a tendency towards genome size expansion, mostly driven by increasing content of transposable elements (TEs).
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Molecular Inversion Probe: A New Tool for Highly Specific Detection of Plant Pathogens

Molecular Inversion Probe: A New Tool for Highly Specific Detection of Plant Pathogens | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
PLOS ONE: an inclusive, peer-reviewed, open-access resource from the PUBLIC LIBRARY OF SCIENCE. Reports of well-performed scientific studies from all disciplines freely available to the whole world.

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The Xylanase Inhibitor Taxi-Iii Counteracts The Necrotic Activity of A Fusarium Graminearum Xylanase in Vitro and in Durum Wheat Transgenic Plants - Moscetti - Molecular Plant Pathology - Wiley Onl...

The Xylanase Inhibitor Taxi-Iii Counteracts The Necrotic Activity of A Fusarium Graminearum Xylanase in Vitro and in Durum Wheat Transgenic Plants - Moscetti - Molecular Plant Pathology - Wiley Onl... | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it

The xylanase inhibitor TAXI-III has been proved to delay Fusarium head blight (FHB) symptoms caused by Fusarium graminearum in transgenic durum wheat plants. To elucidate the molecular mechanism underlying the capacity of the TAXI-III transgenic plants to limit FHB symptoms, we treated wheat tissues with the xylanase FGSG_03624 hitherto shown to induce cell death and hydrogen peroxide accumulation. Experiments performed on lemmas of flowering wheat spikes and wheat cell suspension cultures demonstrated that pre-incubation of xylanase FGSG_03624 with TAXI-III significantly decreased cell death. Most interestingly, a reduced cell death was also obtained by treating, with the same xylanase, lemmas of TAXI-III transgenic plants as compared to control non transgenic plants. Molecular modelling studies predicted an interaction between the TAXI-III residue H395 and residues E122 and E214 belonging to the active site of xylanase FGSG_03624. These results provide, for the first time, clear indications in vitro and in planta that a xylanase inhibitor can prevent the necrotic activity of a xylanase and suggest that the reduced FHB symptoms on transgenic TAXI-III plants can be due not only to the direct inhibition of xylanase activity secreted by the pathogen but also to the capacity of TAXI-III to avoid host cell death.


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The Transcription Factor Ste12 Mediates the Regulatory Role of the Tmk1 MAP Kinase in Mycoparasitism and Vegetative Hyphal Fusion in the Filamentous Fungus Trichoderma atroviride

The Transcription Factor Ste12 Mediates the Regulatory Role of the Tmk1 MAP Kinase in Mycoparasitism and Vegetative Hyphal Fusion in the Filamentous Fungus Trichoderma atroviride | MicroRNAs in plant-pathogen interactions: Small RNAs big impact | Scoop.it
PLOS ONE: an inclusive, peer-reviewed, open-access resource from the PUBLIC LIBRARY OF SCIENCE. Reports of well-performed scientific studies from all disciplines freely available to the whole world.

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Frontiers | Epigenetic control of effectors in plant pathogens | Plant Genetics and Genomics

Plant pathogens display impressive versatility in adapting to host immune systems. Pathogen effector proteins facilitate disease but can become avirulence (Avr) factors when the host acquires discr...

Via Kamoun Lab @ TSL, Christophe Jacquet
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