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Identification of rice ALLENE OXIDE CYCLASE mutants and the function of jasmonate for defence against Magnaporthe oryzae - Riemann - The Plant Journal - Wiley Online Library

Identification of rice ALLENE OXIDE CYCLASE mutants and the function of jasmonate for defence against Magnaporthe oryzae - Riemann - The Plant Journal - Wiley Online Library | Rice Blast | Scoop.it

The level of JA-isoleucine (JA-Ile), a bioactive form of jasmonate, increased in response to blast infection. Furthermore, blast-induced accumulation of phytoalexins, especially that of the flavonoid sakuranetin, was found to be severely impaired in cpm2 and hebiba. Together, the present study demonstrates that in rice jasmonate mediates the defence response against blast fungus.

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Rice Blast
Scientific articles on rice blast and wheat blast 20 new articles each month !
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Colloque SFP 2015

Colloque SFP 2015 | Rice Blast | Scoop.it
Sessions thématiques

1. Taxonomie, diagnostic et détection des agents phytopathogènes

2. Interactions plante-pathogène et plante-symbiote : mécanismes, vection, génomique et réponse de la plante

3. Épidémiologie aux différentes échelles, génétique des populations et écologie évolutive du parasitisme et de la symbiose

4. Protection des plantes, résistance durable, nouvelles technologies et gestion des risques

Les sessions seront introduites par un conférencier invité.  Ont déjà donné leur accord :

    Dr Olivier LE GALL,

    Pr Saskia HOGENHOUT,

    Dr Dominique BLANCARD,

    Dr Pascal SIMONET,

    Pr Philippe LEPOIVRE,

Des sessions "posters" seront aussi organisées.

Enfin, le colloque propose également une session ouverte au grand public consacré aux métiers de la phytopathologie (enseignement, recherche privée, épidémio-surveillance, phytodiagnostic, conseil agricole, journalisme agricole).

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Magnaporthe Rab5 homologs show distinctfunctions in NGF-mediated neurite outgrowth and cell differentiation

Magnaporthe Rab5 homologs show distinctfunctions in NGF-mediated neurite outgrowth and cell differentiation | Rice Blast | Scoop.it
Nerve growth factor (NGF) binds to TrkA and forms a NGF/TrkA complex at the cell surface, which is then internalized into signaling endosomes and promotes neuronal survival and neurite outgrowth. The small GTPase Rab5 is reported to localize on the plasma membrane and early endosomes, regulating endosome fusion. It was reported that endogenous Rab5 function may need to be suppressed during NGF-induced neurite outgrowth and cell differentiation. Two Rab5 homologs (MoRab5A:MGG_06241 and MoRab5B:MGG_01185) were identified and characterized from the rice blast fungus Magnapothe oryzae, and MoRab5B was identified as the Rab5 ortholog promoting early endosomal fusion, while MoRab5A specialized to perform a non-redundant function in endosomal sorting. In this study, we examined whether MoRab5A and MoRab5B play different roles in NGF-induced neurite outgrowth and cell differentiation in PC12 cells (a rat pheochromocytoma cell line). Our data showed that MoRab5B is a negative regulator of NGF signaling and neurite outgrowth in PC12 cells, similar to human Rab5 (hRab5). MoRab5B:WT inhibits NGF signaling-dependent neurite outgrowth while the dominant-negative MoRab5B mutant (MoRab5B:DN) enhances NGF signaling and neurite outgrowth. In contrast, MoRab5A:WT and MoRab5A:DN both significantly promote NGF-induced neurite outgrowth, indicating that MoRab5B is more similar to hRab5 than MoRab5A in the regulation of NGF signal transduction.
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Nucleotide variation and identification of novel blast resistance alleles of Pib by allele mining strategy

Pib is one of significant rice blast resistant genes, which provides resistance to wide range of isolates of rice blast pathogen, Magnaporthe oryzae. Identification and isolation of novel and beneficial alleles help in crop enhancement. Allele mining is one of the best strategies for dissecting the allelic variations at candidate gene and identification of novel alleles. Hence, in the present study, Pib was analyzed by allele mining strategy, and coding and non-coding (upstream and intron) regions were examined to identify novel Pib alleles. Allelic sequences comparison revealed that nucleotide polymorphisms at coding regions affected the amino acid sequences, while the polymorphism at upstream (non-coding) region affected the motifs arrangements. Pib alleles from resistant landraces, Sercher and Krengosa showed better resistance than Pib donor variety, might be due to acquired mutations, especially at LRR region. The evolutionary distance, Ka/Ks and phylogenetic analyzes also supported these results. Transcription factor binding motif analysis revealed that Pib Sr had a unique motif (DPBFCOREDCDC3), while five different motifs differentiated the resistance and susceptible Pib alleles. As the Pib is an inducible gene, the identified differential motifs helps to understand the Pib expression mechanism. The identified novel Pib resistant alleles, which showed high resistance to the rice blast, can be used directly in blast resistance breeding program as alternative Pib resistant sources.
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Identification and characterization of a novel gene encoding the NBS1 protein in Pyricularia oryzae

The ascomycete Pyricularia oryzae (teleomorph: Magnaporthe oryzae) causes one of the most serious diseases known as rice blast. The Nijmegen breakage syndrome protein (NBS1) is essential for DNA repair; thus, we studied the P. oryzae NBS1 homolog (PoNBS1). A PoNBS1 null mutant exhibited high sensitivity to DNA damage-inducing agents. The mutant also exhibited the retarded hyphal growth, and induced abnormal conidial germination and shape, but showed normal appressorium formation. The phenotypes of the null mutant were complemented by introducing the cDNA of PoNBS1 driven by a TrpC promoter of Aspergillus nidulans. In addition, the null mutant similarly complemented with the PoNBS1 cDNA lacking the FHA domain that had a normal phenotype except for hyphal growth. These results suggest that PoNBS1 is involved in DNA repair and normal development in P. oryzae. Moreover, the FHA domain of PoNBS1 participates in normal hyphal growth.
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QTLs Analysis for Resistance to Blast Disease in US Weedy Rice

Understanding the genetic architecture of adaptation is of great importance in evolutionary biology. US weedy rice is well-adapted to the local conditions in US rice fields. Rice blast disease is one of the most destructive diseases of cultivated rice worldwide. However, information about resistance to blast in weedy rice is limited. Here, we evaluated the disease reactions of 60 US weedy rice accessions with 14 blast races, and investigated the QTLs associated with blast resistance in two major ecotypes of US weedy rice. Our results revealed that US weedy rice exhibited a broad resistance spectrum. Using genotyping by sequencing (GBS), we identified 28 resistance quantitative trait loci (QTLs) in two US weedy rice ecotypes. The resistance QTLs with relatively large and small effects suggests that US weedy rice groups have adapted to blast disease using two ways, both major resistance genes and QTLs. Three genomic loci shared by some of the resistance QTLs indicated that these loci may contribute to no-race-specific resistance in weedy rice. Comparing with known blast disease resistance (R) genes, we found that the R genes at these resistance QTLs are novel, suggesting that US weedy rice is a potential source of novel blast R genes for resistant breeding.
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Naturally produced citral can significantly inhibit normal physiology and induce cytotoxicity on Magnaporthe grisea

Naturally produced citral can significantly inhibit normal physiology and induce cytotoxicity on Magnaporthe grisea | Rice Blast | Scoop.it

Citral is a natural product, which is extracted from the Litsea cubeba fruits.
Bioassay results showed that citral possesses a broad spectrum of bioactivity.
Citral may result in physiology changes in Magnaporthe grisea, thus causing cytotoxicity.
Naturally produced citral could be a potential fungicide.

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Substitution of tryptophan 89 with tyrosine switches the DNA binding mode of PC4

Substitution of tryptophan 89 with tyrosine switches the DNA binding mode of PC4 | Rice Blast | Scoop.it
PC4, a well-known general transcription cofactor, has multiple functions in transcription and DNA repair. Residue W89, is engaged in stacking interactions with DNA in PC4, but substituted by tyrosine in some PC4 orthologous proteins. In order to understand the consequences and reveal the molecular details of this substitution we have determined the crystal structures of the PC4 orthologue MoSub1 and a PC4 W89Y mutant in complex with DNA. In the structure of MoSub1-DNA complex, Y74 interacts directly with a single nucleotide of oligo DNA. By comparison, the equivalent residue, W89 in wild type PC4 interacts with two nucleotides and the base of the second nucleotide has distinct orientation relative to that of the first one. A hydrophobic patch around W89 that favours interaction with two nucleotides is not formed in the PC4 W89Y mutant. Therefore, the change of the surface hydrophobicity around residue 89 results in a difference between the modes of DNA interaction. These results indicate that the conserved Y74 in MoSub1 or W89 in PC4, are not only key residues in making specific interactions with DNA but also required to determine the DNA binding mode of PC4 proteins.
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Characterization of resistance genes to rice blast fungus Magnaporthe oryzae in a “Green Revolution” rice variety

The indica rice variety Dee Geo Woo Gen (DGWG) was the source of the semidwarf gene (SD1) which played an important role in the Green Revolution. In the present study, resistance (R) genes to the US race (isolate) IB54 of Magnaporthe oryzae, causal agent of rice blast disease, was investigated. Two recombinant inbred line mapping populations, consisting of 175 and 224 individuals derived from crosses of DGWG with the straw hull weedy rice type PI653435 (AR-2001-1135; S population) and the black hull type PI653419 (MS-1996-9; B population), respectively, were used for mapping blast R genes and quantitative trait loci (QTLs). Two high-resolution linkage maps with 6,513 (S population) and 14,382 (B population) single nucleotide polymorphic markers derived from genotyping-by-sequencing data were used to map R genes. Two partial resistance QTLs, qBR1.1 and qBR6.1, and one major resistance QTL, qBR11.1, were identified in the B population. One partial resistance QTL, qBR6.1, and one major resistance QTL, qBR11.1, were confirmed with the S population. The total phenotypic variation of three resistance QTLs was 51 %, ranging from 1.12 to 47.62 %, in the B population. All three resistance QTLs were localized to relatively small genomic regions. The major resistance QTL, qBR11.1, was mapped to a 129-kb region on chromosome 11 near nine known blast R genes. Within this 129-kb region, three genes encoding putative nucleotide-binding site and leucine-rich repeat (LRR) disease resistance proteins and three genes encoding WRKY transcription factors WRKY61, WRKY63, and WRKY41 were identified as candidate genes of qBR11.1 and tentatively designated as Pi66(t). Identification of blast R genes in DGWG should help continued deployment of useful genes for improving crop productivity and resistance to rice blast disease.
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Toward monophyletic generic concepts in Magnaporthales: species with Harpophora asexual states

We investigated the phylogenetic relationships among Magnaporthales fungi with harpophora-like asexual states based on DNA sequences of ITS, MCM7, RPB1 and TEF1 genes. The results indicated that these species are polyphyletic. Based on the four-gene phylogeny, the type species of Harpophora, H. radicicola, belongs to Gaeumannomyces and thus Harpophora is treated as a synonym of Gaeumannomyces. In addition a monotypic new genus, Falciphora, is established based on F. oryzae, previous referred as Harpophora oryzae.
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Upstream regulatory architecture of rice genes: summarizing the baseline towards genus-wide comparative analysis of regulatory networks and allele mining

Upstream regulatory architecture of rice genes: summarizing the baseline towards genus-wide comparative analysis of regulatory networks and allele mining | Rice Blast | Scoop.it
Dissecting the upstream regulatory architecture of rice genes and their cognate regulator proteins is at the core of network biology and its applications to comparative functional genomics. With the rapidly advancing comparative genomics resources in the genus Oryza, a reference genome annotation that defines the various cis-elements and trans-acting factors that interface each gene locus with various intrinsic and extrinsic signals for growth, development, reproduction and adaptation must be established to facilitate the understanding of phenotypic variation in the context of regulatory networks. Such information is also important to establish the foundation for mining non-coding sequence variation that defines novel alleles and epialleles across the enormous phenotypic diversity represented in rice germplasm. This review presents a synthesis of the state of knowledge and consensus trends regarding the various cis-acting and trans-acting components that define spatio-temporal regulation of rice genes based on representative examples from both foundational studies in other model and non-model plants, and more recent studies in rice. The goal is to summarize the baseline for systematic upstream sequence annotation of the rapidly advancing genome sequence resources in Oryza in preparation for genus-wide functional genomics. Perspectives on the potential applications of such information for gene discovery, network engineering and genomics-enabled rice breeding are also discussed.
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Chloroplast-Expressed MSI-99 in Tobacco Improves Disease Resistance and Displays Inhibitory Effect against Rice Blast Fungus

Chloroplast-Expressed MSI-99 in Tobacco Improves  Disease Resistance and Displays Inhibitory Effect against  Rice Blast Fungus | Rice Blast | Scoop.it

The antimicrobial peptide MSI-99 has been suggested as an antimicrobial peptide conferring resistance to bacterial and fungal diseases. Here, a vector harboring the MSI-99 gene was constructed and introduced into the tobacco chloroplast genome via particle bombardment. The MSI-99-containing protein extracts were firstly proved in vitro and in vivo to display significant suppressive effects on two rice blast isolates. These findings provide a strong basis for the development of new biopesticides to combat rice blast.

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Natural variation of rice blast gene Pi-d2

In the present study, the protein coding regions of the rice R gene Pi-d2 in 35 rice accessions, including Oryza sativa L. subsp. indica Kato (Aus),indica (IND), temperate japonica (TEJ), tropical japonica (TRJ), aromatic (ARO); subgroups ofOryza sativa; 6 accessions of wild rice varieties; O. nivara; and O. rufipogon were analyzed. A total of 13 nucleotide differences were found in the open reading frames (ORFs) of Pi-d2.Translation of these ORFs revealed 9 variants; 3 were novel Pi-d2 variants. Variants H2 and H5 were identified in accessions of cultivated rice and O. nivara, H1, H3, H4, H6, and H8 were only identified in cultivated rice. H2 and H5 were the common types of IND and O. nivara, H8 was the common type of TRJ and AUS, H6 was the specific type of AUS, and H3 was the specific type of ARO. H7 and H9 were specific haplotypes of O. nivara and O. rufipogon, respectively. These findings demonstrate that Pi-d2 variants are useful indicators for each subgroup, and Pi-d2 is an ancient gene that predates speciation of rice subgroups.

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Bio-efficacy of different fungicides in managing blast of rice caused by Pyricularia grisea

In vitro evaluation of different fungicides indicated that tebuconazole proved most effective as it completely inhibited the colony growth of P.grisea at 10 μg/ml whereas azoxystrobin + difenconazole, propiconazole and difenconazole completely inhibited the colony growth of the pathogen at 25 μg/ml. rest of fungicides viz. zineb, tricyclazole, kasugamycin and azoxystrobin proved least effective even at a concentration of 200 μg/. under pot culture conditions, tebuconazole at 0.1 per cent was found to be highly effective in reducing leaf blast severity followed by propiconazole at 0.1 per cent. Under field conditions, the efficacy of propiconazole, tricyclazole, tebuconazole and azoxystrobin + difenconazole was at par and proved to be effective fungicides in reducing the leaf and neck blast severity and increasing the yield.

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Efficacy of Selected Plant Extracts against Pyricularia grisea, Causal Agent of Rice Blast Disease

Efficacy of Selected Plant Extracts against Pyricularia grisea, Causal Agent of Rice Blast Disease | Rice Blast | Scoop.it
Rice blast disease, caused by a seed-borne fungus Pyricularia grisea, is an important and serious disease of rice (Oryza sativa L.) worldwide. The disease has been reported to cause yield losses of up to 40% in Tanzania. Studies were conducted to determine the effect of aqueous extracts of Aloe vera, Allium sativum, Annona muricata, Azadirachta indica, Bidens pilosa, Camellia sinensis, Chrysanthemum coccineum, processed Coffee arabica, Datura stramonium, Nicotiana tabacum and Zingiber officinalis for control of rice blast disease (Pyricularia grisea) in-vitro and in-vivo. The results indicate that processed C. arabica at 10% and 25% (v/v) had the highest (81.12%) and (89.40%) inhibitory effect, respectively, against P. grisea. Aqueous extract from N. tabacum at 10% concentration ranked third (80.35%) in inhibiting P. grisea. These were followed by extracts from 25% A. vera (79.45%) and 25% C. coccineum flower (78.83%). The results also indicate that, extracts from A. indica, A. vera, A. sativum, C. arabica, D. stramonium, C. sinensis, Z. officinalis and N. tabacum did not have any phytotoxic effect on seed germination, shoot height, root length, dry weight, seedling growth and seedling vigour index. These plant extracts can thus be used for rice seed treatment to manage rice blast disease.
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High osmolarity glycerol (HOG) signaling in Magnaporthe oryzae: Identification of MoYPD1 and its role in osmoregulation, fungicide action and pathogenicity

High osmolarity glycerol (HOG) signaling in Magnaporthe oryzae: Identification of MoYPD1 and its role in osmoregulation, fungicide action and pathogenicity | Rice Blast | Scoop.it

The first functional characterization of an YPD1-homologue in filamentous phytopathogenic fungi.
We investigated a yeast YPD1-homologue and its role concerning signal transfer within the phosphorelay system of the HOG pathway.
We provide a Y2H analysis of the signaling proteins in the phosphorelaysystem of the HOG pathway in Magnaporthe oryzae.
MoYpd1 is involved in the fungicide action of fludioxonil.
ΔMoypd1 has a white and fluffy phenotype and is not able to form spores and colonise rice plants.

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Molecular Screening of Blast Resistance Genes in Rice using SSR Markers

Molecular Screening of Blast Resistance Genes in Rice using SSR Markers | Rice Blast | Scoop.it
Rice Blast is the most devastating disease causing major yield losses in every year worldwide. It had been proved that using resistant rice varieties would be the most effective way to control this disease. Molecular screening and genetic diversities of major rice blast resistance genes were determined in 192 rice germplasm accessions using simple sequence repeat (SSR) markers. The genetic frequencies of the 10 major rice blast resistance genes varied from 19.79% to 54.69%. Seven accessions IC337593, IC346002, IC346004, IC346813, IC356117, IC356422 and IC383441 had maximum eight blast resistance gene, while FR13B, Hourakani, Kala Rata 1–24, Lemont, Brown Gora, IR87756-20-2-2-3, IC282418, IC356419, PKSLGR-1 and PKSLGR-39 had seven blast resistance genes. Twenty accessions possessed six genes, 36 accessions had five genes, 41 accessions had four genes, 38 accessions had three genes, 26 accessions had two genes, 13 accessions had single R gene and only one accession IC438644 does not possess any one blast resistant gene. Out of 192 accessions only 17 accessions harboured 7 to 8 blast resistance genes.
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Plant-PrAS: A Database of Physicochemical and Structural Properties and Novel Functional Regions in Plant Proteomes

Plant-PrAS: A Database of Physicochemical and Structural Properties and Novel Functional Regions in Plant Proteomes | Rice Blast | Scoop.it

Via Biswapriya Biswavas Misra
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Biswapriya Biswavas Misra's curator insight, March 15, 10:13 PM

Arabidopsis thaliana is an important model species for studies of plant gene functions. Research on Arabidopsis has resulted in the generation of high-quality genome sequences, annotations and related post-genomic studies. The amount of annotation, such as gene-coding regions and structures, is steadily growing in the field of plant research. In contrast to the genomics resource of animals and microorganisms, there are still some difficulties with characterization of some gene functions in plant genomics studies. The acquisition of information on protein structure can help elucidate the corresponding gene function because proteins encoded in the genome possess highly specific structures and functions. In this study, we calculated multiple physicochemical and secondary structural parameters of protein sequences, including length, hydrophobicity, the amount of secondary structure, the number of intrinsically disordered regions (IDRs) and the predicted presence of transmembrane helices and signal peptides, using a total of 208,333 protein sequences from the genomes of six representative plant species, Arabidopsis thaliana, Glycine max (soybean), Populus trichocarpa (poplar), Oryza sativa (rice),Physcomitrella patens (moss) and Cyanidioschyzon merolae (alga). Using the PASS tool and the Rosetta Stone method, we annotated the presence of novel functional regions in 1,732 protein sequences that included unannotated sequences from the Arabidopsis and rice proteomes. These results were organized into the Plant Protein Annotation Suite database (Plant-PrAS), which can be freely accessed online at http://plant-pras.riken.jp/.

 
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NLR Biology in Plants and Animals - Interactions, Bavaria, Germany from May 3–6, 2015

NLR Biology in Plants and Animals - Interactions, Bavaria, Germany from May 3–6, 2015 | Rice Blast | Scoop.it

This workshop aims to draw together researchers in plant and animal NLR biology to discuss recent conceptual advances and future directions for the field. The workshop will take place at Schloss Ringberg in Bavaria, Germany from May 3–6, 2015. View the workshop poster for more information on how to register and submit an abstract.


Via Kamoun Lab @ TSL
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Identification of three major R genes responsible for broad-spectrum blast resistance in an indica rice accession

Identification of three major R genes responsible for broad-spectrum blast resistance in an indica rice accession | Rice Blast | Scoop.it
An indica rice accession HR4 was found to exhibit good resistance to rice blast in previous research. Inoculation with 116 different M. oryzae isolates revealed that HR4 has the broadest resistance spectrum of the six rice cultivars used in this study, which included two well characterized broad-spectrum resistance sources. To uncover the genetic mechanism of the broad-spectrum resistance in HR4, genetic analysis was carried out with three stable isolates. The results showed that a single dominant gene controlled its resistance to isolates GD93286 and GD00193, whereas two independent dominant genes were responsible for its resistance to isolate GD08T4. The resistance (R) gene in HR4 corresponding to isolate GD93286, named Pi-h1(t), was found to reside in a region of ~235.9 kb on the long arm of chromosome 11, while the other two R genes identified with isolate GD08T4, named Pi-h2(t) and Pi-h3(t), were linked to markers on chromosomes 1 and 12, respectively. The results indicated that the broad-spectrum resistance to rice blast in HR4 could be ascribed to multiple R genes. Identification of such multiple R genes will allow us to use markers more effectively for resistance improvement in rice breeding programs.
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Plant Omics - Identification and network construction of zinc finger protein (ZFP) genes involved in the rice-'Magnaporthe oryzae' interaction

Plant Omics - Identification and network construction of zinc finger protein (ZFP) genes involved in the rice-'Magnaporthe oryzae' interaction | Rice Blast | Scoop.it
Previous studies have shown that some rice ZFP genes from the WRKY, RIN C2H2 and LSD1 families are associated with defense against Magnaporthe oyzae (M ozae). However, it remains miluioi whether other ZFP families are involved in the rice-M oyzae interaction. Here, we reported the global characterization of rice ZFP genes involved in the rice-M oryzae interaction based on bioinfromatics analysis of important rice databases. By analyzing the data obtained from the microarray database, we found that 241 ZFP genes belonging to 27 thmiies were expression-responsive toM oyzae. Among these ZFP thmiies, a total of 23 ZFP families were newly identified to be involved into the rice-M oyzae interaction. The expression patterns of the ZFP genes with expression responsiveness to M oyzae in each thmily were similar, suggesting that each family might play similar roles in the rice-M oyzae interaction. The result of co- expression gene network analysis revealed that the M oIae-responsive ZFP genes were able to be co-expressed with those genes regulating some biological processes. These biological processes mainly included methylation modification, protein kinase activity, transcription activity, posttranscriptional modification and protein transfer. The result suggested that the regulated network of the rice-M oyzae interaction was well organized, although it was complicated. Moreover, we identified four ZFP genes that might play important roles for regulating blast disease resistance.
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Whole genome comparative analysis of transposable elements provides new insight into mechanisms of their inactivation in fungal genomes

Background Transposable Elements (TEs) are key components that shape the organization and evolution of genomes. Fungi have developed defense mechanisms against TE invasion such as RIP (Repeat-Induced Point mutation), MIP (Methylation Induced Premeiotically) and Quelling (RNA interference). RIP inactivates repeated sequences by promoting Cytosine to Thymine mutations, whereas MIP only methylates TEs at C residues. Both mechanisms require specific cytosine DNA Methyltransferases (RID1/Masc1) of the Dnmt1 superfamily. Results We annotated TE sequences from 10 fungal genomes with different TE content (1-70%). We then used these TE sequences to carry out a genome-wide analysis of C to T mutations biases. Genomes from either Ascomycota or Basidiomycota that were massively invaded by TEs (Blumeria, Melampsora, Puccinia) were characterized by a low frequency of C to T mutation bias (10-20%), whereas other genomes displayed intermediate to high frequencies (25-75%). We identified several dinucleotide signatures at these C to T mutation sites (CpA, CpT, and CpG). Phylogenomic analysis of fungal Dnmt1 MTases revealed a previously unreported association between these dinucleotide signatures and the presence/absence of sub-classes of Dnmt1. Conclusions We identified fungal genomes containing large numbers of TEs with many C to T mutations associated with species-specific dinucleotide signatures. This bias suggests that a basic defense mechanism against TE invasion similar to RIP is widespread in fungi, although the efficiency and specificity of this mechanism differs between species. Our analysis revealed that dinucleotide signatures are associated with the presence/absence of specific Dnmt1 subfamilies. In particular, an RID1-dependent RIP mechanism was found only in Ascomycota.

Via Francis Martin
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Silicon induced systemic defense responses in perennial ryegrass against infection by Magnaporthe oryzae

Silicon induced systemic defense responses in perennial ryegrass against infection by Magnaporthe oryzae | Rice Blast | Scoop.it
Sustainable integrated disease management for gray leaf spot of perennial ryegrass may involve use of plant defense elicitors with compatible traditional fungicides to reduce disease incidence and severity. Silicon (Si) has previously been identified as a potential inducer or modulator of plant defenses against different fungal pathogens. To this end, perennial ryegrass was inoculated with the causal agent of gray leaf spot, Magnaporthe oryzae, when grown in soil that was non-amended or amended with three different levels of calcium silicate (1, 5, or 10 metric ton/ha). When applied at a rate of 5 metric ton/ha, calcium silicate was found to significantly suppress gray leaf spot in perennial ryegrass including a significant reduction of disease incidence (39.5%) and disease severity (47.3%). Additional studies observed non-penetrated papillae or cell-wall appositions harboring callose, phenolic autofluorogens, and lignin-associated polyphenolic compounds in grass grown in the Si-amended soil. Regarding defense-associated enzyme levels, only following infection did grass grown in Si-amended soil exhibit greater activities of peroxidase (PRX) and polyphenol oxidase (PPO) than equivalent inoculated control plants. Also following infection with M. oryzae, grass levels of several phenolic acids, including chlorogenic acid and flavonoids, and relative expression levels of genes encoding phenylalanine ammonia lyase (PALa and PALb) and lipoxygenase (LOXa) significantly increased in Si-amended plants compared to that of non-amended control plants. These results suggest that Si-mediated increase of host defense responses to fungal pathogens in perennial ryegrass has a great potential to be part of an effective integrated disease management strategy against gray leaf spot development.
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36th New Phytologist Symposium: Cell biology at the plant–microbe interface

36th New Phytologist Symposium: Cell biology at the plant–microbe interface | Rice Blast | Scoop.it
Welcome and invitation

On behalf of the New Phytologist Trust and symposium organisers I am pleased to invite you to participate in a symposium entitled ‘Cell biology at the plant–microbe interface’ to be held at  the Eden Hotel Wolff, Munich, Germany, 29 November – 1 December 2015. 

Registration and key dates

Registration is now open. Grant application deadline - 4 September 2015. 

Poster abstract submission deadline - 2 October 2015.

 

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