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A serine/threonine-protein phosphatase PP2A catalytic subunit is essential for asexual development and plant infection in Magnaporthe oryzae - Online First - Springer

A serine/threonine-protein phosphatase PP2A catalytic subunit is essential for asexual development and plant infection in Magnaporthe oryzae - Online First - Springer | Rice Blast | Scoop.it

Protein phosphatase 2A is a subgroup of widely conserved serine/threonine phosphatases and plays diverse roles in transcription, translation, differentiation, cell cycle, and signal transduction in many organisms. Taken together, our results indicated that PP2Ac plays vital roles in asexual development and plant infection by regulating Rho GTPases in the rice blast fungus and perhaps other plant pathogenic fungi.

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Rice Blast
Scientific articles on rice blast and wheat blast 20 new articles each month !
Curated by Elsa Ballini
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Pex14/17, a filamentous fungi specific peroxin, is required for import of peroxisomal matrix proteins and full virulence of Magnaporthe oryzae

Pex14/17, a filamentous fungi specific peroxin, is required for import of peroxisomal matrix proteins and full virulence of Magnaporthe oryzae | Rice Blast | Scoop.it
Peroxisomes are ubiquitous organelles in eukaryotic cells that fulfill a variety of biochemical functions. The biogenesis of peroxisomes requires a variety of proteins named peroxins, which are encoded by PEX genes. Pex14/17 is a putative peroxin recently identified, specifically present in filamentous fungal species. Its function in peroxisomal biogenesis is still obscure and its roles in fungal pathogenicity are yet undocumented. Here, we demonstrated the contributions of Pex14/17 in the rice blast fungus Magnaporthe oryzae (Mopex14/17) to peroxisomal biogenesis and fungal pathogenicity by targeting gene replacement strategies. Mopex14/17 has properties of both Pex14 and Pex17 in protein sequence. Mopex14/17 is distributed at the peroxisomal membrane and is essential for efficient peroxisomal targeting of proteins containing peroxisomal targeting signal 1. The MoPEX19 deletion led to the cytoplasmic distribution of Mopex14/17, indicating the peroxisomal import of Pex14/17 depends on Pex19. The knockout mutants of MoPEX14/17 were reduced in fatty acids utilization, reactive oxygen species (ROS) degradation and cell wall integrity. Moreover, the Δmopex14/17 mutants were delayed in conidial generation and appressorial formation, and reduced in appressorial turgor accumulation and penetration ability into host plants. These defects resulted in a significant reduction of the virulence of the mutant. These data indicated that MoPEX14/17 plays crucial roles in peroxisome biogenesis and contributes to fungal development and pathogenicity. This article is protected by copyright. All rights reserved.
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The non-host pathogen Puccinia triticina elicits an active transcriptional response in rice

The non-host pathogen Puccinia triticina elicits an active transcriptional response in rice | Rice Blast | Scoop.it
Rice (Oryza sativa L.) is not susceptible to rust fungi, including the wheat leaf rust fungus Puccinia triticina. Upon inoculation with P. triticina spores, infection hyphae and appressoria were observed on the leaf surfaces of the rice cultivar Nipponbare. The cultivar responded to the inoculation with brown discoloration of the local tissue and fragmentation of rust infection hyphae and appressoria. A microarray gene-expression analysis of the host transcriptional response was performed 24 h after inoculation, revealing rice genes that were up- or down-regulated following the interaction. In particular, the loci represented by five probe sets (Os.55776.1. S1_x_at, Os.55647.1. A1_at, Os.55776.1. S1_at, OsAffx.10944.1. S1_x_at, and OsAffx.10944.1. S1_at) displayed the highest increase in gene expression compared to the control inoculation. The probe sets included members of the receptor-like kinase family (RLK) that occurs within a cluster of RLK genes on chromosome 1. Other RLK genes, within the RLK gene cluster and at another location, also showed increases in gene expression after P. triticina inoculation. The RLK genes varied in response to challenges with different rust strains or when challenged with several non-rust wheat pathogens that are also non-pathogenic to rice. The results indicate that rice has an active transcriptional and possible defense priming reaction in response to P. triticina and other non-host fungal pathogens.
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Financial Comparison of Disease Management Methods of Rice Blast Disease in Langerood County, Iran

Financial Comparison of Disease Management Methods of Rice Blast Disease in Langerood County, Iran | Rice Blast | Scoop.it
The objective of the present study was to financially compare chemical and agricultural management methods of rice blast disease, as a prevalent disease in paddy fields of Langerood in Guilan Province, Iran. Thirty-three rice experts and 373 paddy farmers were selected by random sampling procedures. Data were collected by a research made questionnaire and were analyzed by SPSS. Benefit Cost Ratio (BCR) was utilized for analysis to recognize the most efficient disease management method. Given the costs in 2012 and the evaluation of economic variables of chemical disease management procedures in paddy fields per acre, it became evident that agricultural disease management methods can replace the chemical ones financially. Furthermore, the comparison of farmers’ demographic, economic and agricultural characteristics by Chi-squared test among agronomic method and chemical method users showed no significant relationship between paddy farmers’ gender, age and farming experience, but there was a significant relationship between cultivation area and management method at the 0.05 significant level. However, there was a significant correlation between disease management methods and the size of the area under cultivation. Furthermore, there were significant differences between experts and farmers’ professional viewpoints in their preferences of disease management methods. While experts insist on an integrated application of chemical and agricultural procedures, most farmers apply chemical disease management methods
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International Exploratory Workshop 2017: Ecological genomics of coevolutionary interactions

Theoretical models suggest that coevolution promotes reciprocal adaptation at the phenotypic and molecular levels. However, to date there are few conclusive empirical examples of sustained coevolution demonstrating recurrent reciprocal changes driven by natural selection at the phenotypic and genotypic levels. Over the past 10 years, the development of next-generation sequencing (NGS) technologies has unlocked new frontiers for research on the genomics of coevolutionary interactions. Nevertheless, a conceptual bridge between these novel genomics approaches and latest theoretical developments are still sorely lacking to tackle phenotypic and genetic changes associated with coevolution and its response to global environmental change. The focus of our workshop is to fill this gap by bringing together young and senior researchers working on the ecological genomics of coevolutionary interactions at both theoretical and empirical levels.
Aims and Objectives

The goal of our 5-days workshop is to bring together an outstanding group of experts that develop conceptual, theoretical and experimental approaches to study the ecological genomics of coevolutionary interactions. These instructors will introduce workshop participants to modern concepts, models and methods that are widely being used or are currently being developed. The first four days of the workshop will consist of lectures and practical demonstrations given by the instructors, followed by hands-on exercises performed by the participants under guided supervision. The lectures will focus on current topics and latest developments relevant for investigating ecogenomics of coevolutionary interactions (see program: inferring co-demographic histories and testing for co-adaptation). Participants will focus on datasets provided by the instructors in the light of new developments. On the fifth day, thematic talk sessions with presentations from invited speakers and selected participants will illustrate current research on the ecological genomics of coevolution. In order to enhance discussions during the five-day workshop, we will also ask participants to present a poster of their own work on the first day (see “Speed talk and introductory poster session“ in the program) to introduce themselves and their research topic.

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Pyricularia pennisetigena and P. zingibericola from invasive grasses infect signal grass, barley and wheat

Pyricularia pennisetigena and P. zingibericola from invasive grasses infect signal grass, barley and wheat | Rice Blast | Scoop.it
Fungal species from the Pyricularia genus are associated with blast disease in plants from the Poaceae family, causing losses in economically important crops such as rice, oat, rye, barley, wheat and triticale. This study aimed at characterizing the pathogenicity spectrum of P. pennisetigena and P. zingibericola to signal grass, barley and wheat, as well as comparing them with those from the species P. grisea and P. oryzae pathotype Triticum, which occur widely in the Brazilian agroecosystem. Twenty isolates of Pyricularia spp. were obtained from infected leaf samples of invasive plant species from wheat fields. The isolates classification into distinct Pyricularia species was done using molecular phylogeny based on actin and calmodulin genes. Pyricularia pennisetigena and P. zingibericola inoculated on plant leaves, at a concentration adjusted to 105 conidia mL-1, were pathogenic to signal grass, barley and wheat, with varying levels of aggressiveness.
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Plant Genomics. Chapter 8: Genomic Approaches to Developing Molecular Markers Linked to Grey Leaf Spot Resistance Loci in Ryegrasses

Plant Genomics. Chapter 8: Genomic Approaches to Developing Molecular Markers Linked to Grey Leaf Spot Resistance Loci in Ryegrasses | Rice Blast | Scoop.it
Ryegrass grey leaf spot (GLS), which is also called ryegrass blast, is caused by Magnaporthe oryzae (anamorph Pyricularia oryzae). It is a serious disease in ryegrasses including perennial ryegrass (Lolium perenne L.) and Italian ryegrass (L. multiflorum Lam.). Heavily infected young seedlings die within days, and grass stands can be seriously damaged by the disease. Thus, the development of GLS-resistant cultivars has become one of the most important objectives in ryegrass breeding. This chapter provides an overview of the current information regarding molecular marker development in the breeding of GLS-resistant ryegrass cultivars. It focuses on the pathology of GLS, heritability and breeding of GLS resistance, and development of molecular markers linked to a major ryegrass GLS resistance gene.
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Development of a novel strategy for fungal transformation based on a mutant locus conferring carboxin-resistance in Magnaporthe oryzae

Development of a novel strategy for fungal transformation based on a mutant locus conferring carboxin-resistance in Magnaporthe oryzae | Rice Blast | Scoop.it
The accurate manipulation of genomic integration of mutant alleles or fluorescent fusion-protein constructs is necessary for understanding of pathogenic mechanism of Magnaporthe oryzae. Recently, this can be achieved by integrating of exogenous DNA randomly into genome of this pathogen, but ectopic integration may result in alteration of gene expression or gene disruption due to unpredictable position effects and/or disruption of protein-coding regions. In this study, we establish a novel strategy for locus-specific integration of exogenous DNA via carboxin-resistance reconstitution by a point-mutation (H245L) on succinate dehydrogenase subunit Mosdi1. Independent transformants derived from the same reconstitution construct showed consistent fluorescent signal and undiversified phenotypes, including hyphae growth, conidiation and pathogenicity, in M. oryzae. Meanwhile, 96 % of all transformants integrate correctly into the Mosdi1 locus as a single copy. Furthermore, we provide a vector carrying yeast recombination cassette and thus allow assembly of multiple overlapping DNA fragments by yeast in vivo recombination for gene complementation and protein localization assay.
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Role of phenazines and cyclic lipopeptides produced by Pseudomonas sp. CMR12a in induced systemic resistance on rice and bean

Role of phenazines and cyclic lipopeptides produced by Pseudomonas sp. CMR12a in induced systemic resistance on rice and bean | Rice Blast | Scoop.it

Pseudomonas sp. CMR12a produces two different classes of cyclic lipopeptides (CLPs) (orfamides and sessilins), which all play a role in direct antagonism against soilborne pathogens. Here we show that Pseudomonas sp. CMR12a is also able to induce systemic resistance to Magnaporthe oryzae on rice and to the web blight pathogen Rhizoctonia solani AG2-2 on bean. Plant assays with biosynthesis mutants of Pseudomonas sp. CMR12a impaired in the production of phenazines and/or CLPs and purified metabolites revealed that distinct bacterial determinants are responsible for inducing systemic resistance in these two pathosystems. In rice, mutants impaired in phenazine production completely lost their ability to induce systemic resistance, while a soil drench with pure phenazine-1-carboxamide (PCN) at a concentration of 0.1 or 1 µM was active in inducing resistance against M. oryzae. In bean, mutants that only produced phenazines, sessilins or orfamides were still able to induce systemic resistance against Rhizoctonia web blight, but a balanced production of these metabolites was needed. This study not only shows that Pseudomonas sp. CMR12a can protect rice to blast disease and bean to web blight disease, but also displays that the determinants involved in induced systemic resistance are plant, pathogen and concentration dependent. 

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The thioredoxin MoTrx2 protein mediates ROS balance and controls pathogenicity as a target of the transcription factor MoAP1 in Magnaporthe oryzae

The thioredoxin MoTrx2 protein mediates ROS balance and controls pathogenicity as a target of the transcription factor MoAP1 in Magnaporthe oryzae | Rice Blast | Scoop.it
We have previously shown that the transcription factor MoAP1 governs the oxidative response and is important for pathogenicity in the rice blast fungus Magnaporthe oryzae. To explore the underlying mechanism we have identified thioredoxin MoTrx2 as a target of MoAP1 in M. oryzae. Thioredoxins are highly conserved 12-KD oxidoreductase enzymes containing a dithiol-disulfide active site and they function as antioxidants against free radicals such as reactive oxygen species (ROS). In yeast and fungi, thioredoxins are important for oxidative stress tolerance and growth. To study functions of MoTrx2, we generated ΔMotrx2 mutants that exhibit various defects ranging from sulfite assimilation, asexual and sexual differentiation, infectious hyphal growth, and pathogenicity. We found that ΔMotrx2 mutants have a defect in scavenging ROS during host cell invasion and in active suppression of rice defense response. We also found that ΔMotrx2 mutants display higher intracellular ROS levels during conidial germination but lower peroxidase and laccase activities that contribute to its attenuation in virulence. Given the function of MoTrx2 overlaps that of MoAP1 in the stress response and pathogenicity, our findings further support that MoTrx2 is a key thioredoxin protein whose function is subjected to transcriptional regulation by MoAP1 in M. oryzae. This article is protected by copyright. All rights reserved.
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MoDnm1 Dynamin Mediating Peroxisomal and Mitochondrial Fission in Complex with MoFis1 and MoMdv1 Is Important for Development of Functional Appressorium in Magnaporthe oryzae

MoDnm1 Dynamin Mediating Peroxisomal and Mitochondrial Fission in Complex with MoFis1 and MoMdv1 Is Important for Development of Functional Appressorium in  Magnaporthe oryzae | Rice Blast | Scoop.it
Dynamin superfamily members are involved in budding of transport vesicles and division of organelles in eukaryotic cells. To further understand how dynamins function in phytopathogenic fungi, we characterized several dynamin-related proteins from the rice blast fungus M. oryzae. In addition to revealing major conserved dynamin functions, we described how MoDnm1 interacts with mitochondrial fission protein MoFis1 and WD repeat adaptor protein MoMdv1 to mediate peroxisomal and mitochondrial fission, pexophagy and mitophagy. Importantly, we provided evidence to demonstrate that MoDnm1-, MoFis1- and MoMdv1-dependent peroxisomal and mitochondrial functions are linked to differentiation and pathogenicity of the rice blast fungus.
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Analysis of the diversity and function of the alleles of the rice blast resistance genes Piz-t, Pita and Pik in 24 rice cultivars

Analysis of the diversity and function of the alleles of the rice blast resistance genes Piz-t, Pita and Pik in 24 rice cultivars | Rice Blast | Scoop.it
Understanding the sequence diversity of rice blast resistance genes is important for breeding new resistant rice cultivars against the rice blast fungus Magnaporthe oryzae. In this study, we selected 24 rice cultivars with different genetic backgrounds to study the allelic diversity of rice blast resistance genes Piz-t, Pita and Pik. For Piz-t, a total of 17 allelic types were found within the 24 cultivars. Blast inoculations showed that most of the mutations can affect the function of the resistance gene. For Pita, except for the difference at the 918th amino acid, a majority of the 21 mutations were detected among the cultivars. Inoculations with blast isolates carrying Avr-Pita revealed that cultivars with mutations in other sites except for the 918th amino acid did not affect the function of the Pita gene. For Pik, a total of six allelic types were found within the 24 cultivars, but five of them lost the function of the resistance gene. In addition, we found that Piz-t, Pita and Pik were expressed constitutively in the 24 rice cultivars and the expression level was not related to resistance. Our results have provided the sequence diversity information of the resistance genes Piz-t, Pita and Pik among the popular rice cultivars grown in the northeast region of China.
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4th Annual and Final Conference of the Sustain COST Action - Pathogen-informed strategies for sustainable broad-spectrum crop resistance

4th Annual and Final Conference of the Sustain COST Action - Pathogen-informed strategies for sustainable broad-spectrum crop resistance | Rice Blast | Scoop.it
The 4th Annual and Final Conference of the Sustain COST Action (FA1208) on "Pathogen-informed strategies for sustainable broad-spectrum crop resistance" will take place from 1/03/2017 to 3/03/2017 in Bled, Slovenia.

The conference will be held in the Hotel Kompas in Bled, a town on Lake Bled in the North-Western Slovenia, a popular tourist destination in Slovenia. Bled is one hour from the Ljubljana International Airport by public transport.

It will welcome around 120 participants and is organized by Dr. Barbara Gerič Stare (Agricultural Institute of Slovenia) and Dr. Saša Širca (Agricultural Institute of Slovenia).

The pre-registration for the conference closes September 15th.
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Roles of Peroxisomes in the Rice Blast Fungus

Roles of Peroxisomes in the Rice Blast Fungus | Rice Blast | Scoop.it

The rice blast fungus, Magnaporthe oryzae, is a model plant pathogenic fungus and is a severe threat to global rice production. Over the past two decades, it has been found that the peroxisomes play indispensable roles during M. oryzae infection. Given the importance of the peroxisomes for virulence, we review recent advances of the peroxisomes roles during M. oryzae infection processes. We firstly introduce the molecular mechanisms and life cycles of the peroxisomes. And then, metabolic functions related to the peroxisomes are also discussed. Finally, we provide an overview of the relationship between peroxisomes and pathogenicity.

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The 9th Effectome meeting will be held from the 16th to the 18th of November 2016 at the Auberge du Cedre in Lauret, France.

The 9th Effectome meeting will be held from the 16th to the 18th of November 2016 at the Auberge du Cedre in Lauret, France. | Rice Blast | Scoop.it
The Auberge du Cèdre (follow the link for more details) is close to Montpellier that has an international Airport with flights to many destinations in France and Europe and is well connected by train (high speed to Paris, 3 1/2h). For transfer from Montpellier to Lauret and back, shuttles will be organized the 16th and 18th. Participants who wish to book additional nights at the Auberge du Cèdre should contact them directly.
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Evaluation of designated hybrid seed parents of pearl millet for blast resistance

One hundred sixty designated B-lines (maintainers of male sterile lines) of pearl millet were screened for blast resistance under greenhouse conditions along with a resistant (ICMR 06444) and a susceptible (ICMB 95444) check against five pathotype-isolates (Pg 45, Pg 53, Pg 56, Pg 118 and Pg 119) of Magnaporthe grisea. Twenty three lines exhibited seedling stage resistance to 3–5 pathotypes. Of the 23 lines, nine (81B, ICMB 88004, ICMB 92444, ICMB 97222-P1, ICMB 02111, ICMB 06444, ICMB 07111, ICMB 09333 and ICMB 09999) were found resistant to all the five pathotypes. The identified blast resistant lines are agronomically superior breeding lines being hybrid parents designated at ICRISAT. Thus, these lines could be either used in the crossing programs to develop blast resistant hybrid parents or as one of the parents for the development of blast resistant hybrids to diversify the genetic base of blast resistance in future pearl millet hybrids.
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The β-1,3-glucanosyltransferases (Gels) affect the structure of the rice blast fungal cell wall during appressorium-mediated plant infection

The fungal wall is pivotal for cell shape and function and in interfacial protection during host infection and environmental challenge. Here, we provide the first description of the carbohydrate composition and structure of the cell wall of the rice blast fungus Magnaporthe oryzae. We focus on the family of glucan elongation proteins (Gels) and characterise five putative β-1,3-glucan glucanosyltransferases, that each carry the Glycoside Hydrolase 72 signature. We generated targeted deletion mutants of all Gel isoforms, that is the GH72+, which carry a putative carbohydrate-binding module, and the GH72- Gels, without this motif We reveal that M. oryzae GH72+ GELs are expressed in spores and during both infective and vegetative growth, but each individual Gel enzymes is dispensable for pathogenicity. Further, we demonstrated that a ∆gel1∆gel3∆gel4 null mutant has a modified cell wall in which 1,3-glucans have a higher degree of polymerization and are less branched than the wild-type strain. The mutant showed significant differences in global patterns of gene expression, a hyper-branching phenotype and no sporulation, and thus was unable to cause rice blast lesions (except via wounded tissues). We conclude that Gel proteins play significant roles in structural modification of the fungal cell wall during appressorium-mediated plant infection.
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Focused Meeting 2016: The Dynamic Fungus

Focused Meeting 2016: The Dynamic Fungus | Rice Blast | Scoop.it
The Dynamic Fungus event will take place at The Mercure Hotel, Exeter, UK. It is part of the 2016 Focused Meeting series.
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The Mycota - A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research (Titles in this series)

The Mycota - A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research (Titles in this series) | Rice Blast | Scoop.it
Titles in this series - The fungi represent a heterogenous assemblage of eukaryotic microorganisms and have become favored organisms for research at the cellular and molecular level. Such research involvement has been stimulated b
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Examining ubiquitinated peptide enrichment efficiency through an epitope labeled protein

Examining ubiquitinated peptide enrichment efficiency through an epitope labeled protein | Rice Blast | Scoop.it
Ubiquitination is a dynamic process that is responsible for regulation of cellular responses to stimuli in a number of biological systems. Previous efforts to study this post-translational modification have focused on protein enrichment; however, recent research utilizes the presence of the di-glycine (Gly-Gly) remnants following trypsin digestion to immuno-enrich ubiquitinated peptides. Monoclonal antibodies developed to the cleaved ubiquitin modification epitope, (tert-butoxycarbonyl) glycylglycine (Boc-Gly-Gly-NHS)1, are used to identify the Gly-Gly signature. Here, we have successfully generated the Boc-Gly-Gly-NHS modification and showed that when conjugated to a lysine containing protein, such as lysozyme, it can be applied as a standard protein to examine ubiquitinated peptide enrichment within a complex background.
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The protein standard mixture was spiked in at 0.1%, 1%, and 5% (mg lysozymel/mg Magnaporthe oryzae proteins) using total proteins extracted from the fungus Magnaporthe oryzae (M.oryzae) as the complex protein background.
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Complete nucleotide sequence of Magnaporthe oryzae partitivirus 1

A novel double-stranded RNA (dsRNA) mycovirus, designated Magnaporthe oryzae partitivirus 1 (MoPV1), was isolated from a strain of the plant pathogenic fungus Magnaporthe oryzae. The MoPV1 genome has two dsRNA genome segments. The larger segment (1763 bp) has a single open reading frame (ORF) with a conserved RNA-dependent RNA polymerase (RdRp) domain. The smaller segment (1491 bp) contains a single ORF encoding a putative coat protein (CP). Homology searches and phylogenetic analysis indicated that MoPV1 is a new member of the genus Gammapartitivirus. This is the first report of a mycovirus of the family Partitiviridae identified in Magnaporthe oryzae.
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Validation of Reference Genes for Robust qRT-PCR Gene Expression Analysis in the Rice Blast Fungus Magnaporthe oryzae

Validation of Reference Genes for Robust qRT-PCR Gene Expression Analysis in the Rice Blast Fungus  Magnaporthe oryzae | Rice Blast | Scoop.it

We recommend the combinatorial use of two reference genes, belonging to the cytoskeleton and ribosomal synthesis functional groups, MGG_Actin, MGG_40s, MGG_S8 (Ribosomal subunit 40S S8) or MGG_Ef1, which demonstrated low M values across heterogeneous tissues. By contrast, metabolic pathway genes MGG_Fad (FAD binding domain-containing protein) and MGG_Gapdh (Glyceraldehyde-3-phosphate dehydroge

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Development of Gene-Pyramid Lines of the Elite Restorer Line, RPHR-1005 Possessing Durable Bacterial Blight and Blast Resistance

Development of Gene-Pyramid Lines of the Elite Restorer Line, RPHR-1005 Possessing Durable Bacterial Blight and Blast Resistance | Rice Blast | Scoop.it
RPHR-1005, the stable restorer line of the popular medium slender (MS) grain type rice hybrid, DRRH-3 was improved in this study for resistance against bacterial blight (BB) and blast diseases through marker-assisted backcross breeding (MABB). In this study, four major resistance genes (i.e., Xa21 and Xa33 for BB resistance and Pi2 and Pi54 for blast resistance) have been transferred to RPHR-1005 using RPBio Patho-1 (possessing Xa21 + Pi2), RPBio Patho-2 (possessing Xa21 + Pi54) and FBR1-15EM (possessing Xa33) as the donors. Foreground selection was carried out using PCR-based molecular markers specific for the target resistance genes and the major fertility restorer genes, Rf3 and Rf4, while background selection was carried out using a set of parental polymorphic rice SSR markers and backcrossing was continued uptoBC2 generation. At BC2F2, plants possessing the gene combination- Xa21 + Pi2, Xa21 + Pi54 and Xa33 in homozygous condition and with >92% recovery of the recurrent parent genome (RPG) were identified and intercrossed to combine all the four resistance genes. Twenty-two homozygous, pyramid lines of RPHR-1005 comprising of three single-gene containing lines, six 2-gene containing lines, eight 3-gene containing lines, and five 4-gene containing lines were identified among the double intercross lines at F3 generation (DICF3). They were then evaluated for their resistance against BB and blast, fertility restoration ability and for key agro-morphological traits. While single gene containing lines were resistant to either BB or blast, the 2-gene, 3-gene, and 4-gene pyramid lines showed good level of resistance against both and/or either of the two diseases. Most of the 2-gene, 3-gene, and 4-gene containing pyramid lines showed yield levels and other key agro-morphological and grain quality traits comparable to the original recurrent parent and showed complete fertility restoration ability, with a few showing higher yield as compared to RPHR-1005. Further, the experimental hybrids derived by crossing the gene-pyramid lines of RPHR-1005 with APMS6A (the female parent of DRRH-3), showed heterosis levels equivalent to or higher than DRRH-3. The results of present study exemplify the utility of MABB for targeted improvement of multiple traits in hybrid rice.
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The Nipponbare genome and the next-generation of rice genomics research in Japan

The Nipponbare genome and the next-generation of rice genomics research in Japan | Rice Blast | Scoop.it
The map-based genome sequence of the japonica rice cultivar Nipponbare remains to date as the only monocot genome that has been sequenced to a high-quality level. It has become the reference sequence for understanding the diversity among thousands of rice cultivars and its wild relatives as well as the major cereal crops that comprised the food source for the entire human race. This review focuses on the accomplishments in rice genomics in Japan encompassing the last 10 years which have led into deeper understanding of the genome, characterization of many agronomic traits, comprehensive analysis of the transcriptome, and the map-based cloning of many genes associated with agronomic traits.
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Regulatory cross-talks and cascades in rice hormone biosynthesis pathways contribute to stress signaling

Crosstalk among different hormone signaling pathways play an important role in modulating plant response to both biotic and abiotic stress. Hormone activity is controlled by its bio-availability, which is again influenced by its biosynthesis. Thus independent hormone biosynthesis pathways must be regulated and co-ordinated to mount an integrated response. One of the possibilities is to use cis-regulatory elements to orchestrate expression of hormone biosynthesis genes. Analysis of CREs, associated with differentially expressed hormone biosynthesis related genes in rice leaf under Magnaporthe oryzae attack and drought stress enabled us to obtain insights about cross-talk among hormone biosynthesis pathways at the transcriptional level. We identified some master transcription regulators that co-ordinate different hormone biosynthesis pathways under stress. We found that Abscisic acid and Brassinosteroid regulate Cytokinin conjugation; conversely Brassinosteroid biosynthesis is affected by both Abscisic acid and Cytokinin. Jasmonic acid and Ethylene biosynthesis may be modulated by Abscisic acid through DREB transcription factors. Jasmonic acid or Salicylic acid biosynthesis pathways are co-regulated but they are unlikely to influence each other’s production directly. Thus multiple hormones may modulate hormone biosynthesis pathways through a complex regulatory network, where biosynthesis of one hormone is affected by several other contributing hormones.
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Linker Flexibility Facilitates Module Exchange in Fungal Hybrid PKS-NRPS Engineering

Polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs) each give rise to a vast array of complex bioactive molecules with further complexity added by the existence of natural PKS-NRPS fusions. Rational genetic engineering for the production of natural product derivatives is desirable for the purpose of incorporating new functionalities into pre-existing molecules, or for optimization of known bioactivities. We sought to expand the range of natural product diversity by combining modules of PKS-NRPS hybrids from different hosts, hereby producing novel synthetic natural products. We succeeded in the construction of a functional cross-species chimeric PKS-NRPS expressed in Aspergillus nidulans. Module swapping of the two PKS-NRPS natural hybrids CcsA from Aspergillus clavatus involved in the biosynthesis of cytochalasin E and related Syn2 from rice plant pathogen Magnaporthe oryzae lead to production of novel hybrid products, demonstrating that the rational re-design of these fungal natural product enzymes is feasible. We also report the structure of four novel pseudo pre-cytochalasin intermediates, niduclavin and niduporthin along with the chimeric compounds niduchimaeralin A and B, all indicating that PKS-NRPS activity alone is insufficient for proper assembly of the cytochalasin core structure. Future success in the field of biocombinatorial synthesis of hybrid polyketide-nonribosomal peptides relies on the understanding of the fundamental mechanisms of inter-modular polyketide chain transfer. Therefore, we expressed several PKS-NRPS linker-modified variants. Intriguingly, the linker anatomy is less complex than expected, as these variants displayed great tolerance with regards to content and length, showing a hitherto unreported flexibility in PKS-NRPS hybrids, with great potential for synthetic biology-driven biocombinatorial chemistry.
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