scholarly journals Chrysoviruses in Magnaporthe oryzae

Viruses ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 697 ◽  
Author(s):  
Hiromitsu Moriyama ◽  
Syun-ichi Urayama ◽  
Tomoya Higashiura ◽  
Tuong Le ◽  
Ken Komatsu
Keyword(s):  
Magnaporthe Oryzae ◽  
Driving Force ◽  
Rice Blast ◽  
Plant Viruses ◽  
Phytopathogenic Fungi ◽  
Epigenetic Factors ◽  
Physiological Diversity ◽  
The Family ◽  
Host Fungus ◽  
Pathogenic Races

Magnaporthe oryzae, the fungus that causes rice blast, is the most destructive pathogen of rice worldwide. A number of M. oryzae mycoviruses have been identified. These include Magnaporthe oryzae. viruses 1, 2, and 3 (MoV1, MoV2, and MoV3) belonging to the genus, Victorivirus, in the family, Totiviridae; Magnaporthe oryzae. partitivirus 1 (MoPV1) in the family, Partitiviridae; Magnaporthe oryzae. chrysovirus 1 strains A and B (MoCV1-A and MoCV1-B) belonging to cluster II of the family, Chrysoviridae; a mycovirus related to plant viruses of the family, Tombusviridae (Magnaporthe oryzae. virus A); and a (+)ssRNA mycovirus closely related to the ourmia-like viruses (Magnaporthe oryzae. ourmia-like virus 1). Among these, MoCV1-A and MoCV1-B were the first reported mycoviruses that cause hypovirulence traits in their host fungus, such as impaired growth, altered colony morphology, and reduced pigmentation. Recently we reported that, although MoCV1-A infection generally confers hypovirulence to fungi, it is also a driving force behind the development of physiological diversity, including pathogenic races. Another example of modulated pathogenicity caused by mycovirus infection is that of Alternaria alternata chrysovirus 1 (AaCV1), which is closely related to MoCV1-A. AaCV1 exhibits two contrasting effects: Impaired growth of the host fungus while rendering the host hypervirulent to the plant, through increased production of the host-specific AK-toxin. It is inferred that these mycoviruses might be epigenetic factors that cause changes in the pathogenicity of phytopathogenic fungi.

scholarly journals Discovery and Characterization of a Novel Bipartite Botrexvirus From the Phytopathogenic Fungus Botryosphaeria dothidea

2021 ◽  
Vol 12 ◽  
Author(s):  
Mengmeng Yang ◽  
Wenxing Xu ◽  
Xiaoqi Zhou ◽  
Zuokun Yang ◽  
Yanxiang Wang ◽  
...  
Keyword(s):  
Biological Effects ◽  
Plant Viruses ◽  
Open Reading Frames ◽  
Phytopathogenic Fungus ◽  
Botryosphaeria Dothidea ◽  
Bipartite Genome ◽  
The Family ◽  
Host Fungus

In this study, we describe a novel positive, single-stranded (+ss) RNA mycovirus, named Botryosphaeria dothidea botrexvirus 1 (BdBV1), from a phytopathogenic fungus Botryosphaeria dothidea showing abnormal morphology and attenuated virulence. BdBV1 is phylogenetically related to Botrytis virus X (BotVX) and is the second potential member of the proposed genus Botrexvirus in the family Alphaflexiviridae. However, it differs from the monopartite BotVX in that BdBV1 possesses a bipartite genome comprised of two ssRNA segments (RNA1 and RNA2 with lengths of 5,035 and 1,063 nt, respectively). BdBV1 RNA1 and RNA2 encode putative RNA-dependent RNA polymerase (RdRp) and coat protein (CP) genes, which share significant identity with corresponding genes in both fungal and plant viruses. Moreover, open reading frames (ORFs) 2–4 of BdBV1 RNA1 shared no detectable identity with any known viral proteins. Immunosorbent electron microscopy (ISEM) analysis using an antibody against the virus CP generated in vitro revealed that BdBV1 is encapsidated in filamentous particles. A comparison of the biological effects of BdBV1 infection on symptoms and growth in isogenic lines of virus-free and virus-infected B. dothidea revealed that BdBV1 is probably involved in reduced growth and virulence of the host fungus. This study describes and characterizes a novel bipartite botrexvirus, which is closely related to uni- and multi-partite fungal and plant viruses and contributes useful information to a better understanding of virus evolution.

scholarly journals Four Novel Botourmiaviruses Co-Infecting an Isolate of the Rice Blast Fungus Magnaporthe oryzae

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1383
Author(s):  
Yang Liu ◽  
Liyan Zhang ◽  
Ahmed Esmael ◽  
Jie Duan ◽  
Xuefeng Bian ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Untranslated Region ◽  
Sequence Similarity ◽  
Rice Blast Fungus ◽  
Rna Dependent Rna Polymerase ◽  
Stem Loop ◽  
Single Strain ◽  
The Family ◽  
Gdd Motif

Via virome sequencing, six viruses were detected from Magnaporthe oryzae strains YC81-2, including one virus in the family Tombusviridae, one virus in the family Narnaviridae and four viruses in the family Botourmiaviridae. Since the RNA-dependent RNA polymerase (RdRp) of one botourmiavirus show the highest identity (79%) with Magnaporthe oryzae ourmia-like virus 1 (MOLV1), the virus that was grouped into the genus Magoulivirus was designated as Magnaporthe oryzae botourmiavirus 2 (MOBV2). The three other novel botourmiaviruses were selected for further study. The complete nucleotide sequences of the three botourmiaviruses were determined. Sequence analysis showed that virus 1, virus 2, and virus 3 were 2598, 2385, and 2326 nts in length, respectively. The variable 3′ untranslated region (3′-UTR) and 5′-UTR of each virus could be folded into a stable stem-loop secondary structure. Each virus consisted of a unique ORF encoding a putative RdRp. The putative proteins with a conserved GDD motif of RdRp showed the highest sequence similarity to RdRps of viruses in the family Botourmiaviridae. Phylogenetic analysis demonstrated that these viruses were three distinct novel botourmiaviruses, clustered into the Botourmiaviridae family but not belonging to any known genera of this family. Thus, virus 1, virus 2, and virus 3 were designated as Magnaporthe oryzae botourmiavirus 5, 6, and 7 (MOBV5, MOBV6, and MOBV7), respectively. Our results suggest that four distinct botourmiaviruses, MOBV2, MOBV5, MOBV6, and MOBV7, co-infect a single strain of Magnaporthe oryzae, and MOBV5, MOBV6, and MOBV7 are members of three unclassified genera in the family Botourmiaviridae.

scholarly journals Complete nucleotide sequence of a novle botourmiavirus from the rice blast fungus, Magnaporthe oryzae isolate SH05

2021 ◽  
Author(s):  
Qingchao Deng ◽  
Xuan Zhou ◽  
Simnin Shuai ◽  
Hong Zheng ◽  
Hang Ding ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Plasmopara Viticola ◽  
Open Reading Frame ◽  
Genome Comparison ◽  
Rna Dependent Rna Polymerase ◽  
Reading Frame ◽  
Blast Fungus ◽  
The Family

Abstract A novel mycovirus, proposed name Magnaporthe oryzae botourmiavirus 9 (MoBV9), was described in the rice blast fungus, Magnaporthe oryzae isolate SH05. The virus has a positive single-stranded (+) ss RNA genome of 2,812 nucleotides and contains a single open reading frame predicted to encode an RNA-dependent RNA polymerase closely related to some unclassified viruses of the family Botourmiaviridae, such as Plasmopara viticola lesion associated ourmia-like virus 44, Plasmopara viticola lesion associated ourmia-like virus 47and Cladosporium uredinicola ourmiavirus 1. Genome comparison and phylogenetic analysis supported the notion that MoBV9 is a new member of the family Botourmiaviridae.

scholarly journals Investigating the cell and developmental biology of plant infection by the rice blast fungus Magnaporthe oryzae

2021 ◽  
pp. 103562
Author(s):  
Alice Bisola Eseola ◽  
Lauren S. Ryder ◽  
Míriam Osés-Ruiz ◽  
Kim Findlay ◽  
Xia Yan ◽  
...  
Keyword(s):  
Developmental Biology ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Plant Infection ◽  
Blast Fungus

scholarly journals Understanding Rice-Magnaporthe Oryzae Interaction in Resistant and Susceptible Cultivars of Rice under Panicle Blast Infection Using a Time-Course Transcriptome Analysis

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 301
Author(s):  
Vishesh Kumar ◽  
Priyanka Jain ◽  
Sureshkumar Venkadesan ◽  
Suhas Gorakh Karkute ◽  
Jyotika Bhati ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Magnaporthe Oryzae ◽  
Transcriptome Analysis ◽  
Hormonal Regulation ◽  
Rice Blast ◽  
Blast Resistance ◽  
Differentially Expressed ◽  
Specific Response ◽  
Panicle Blast

Rice blast is a global threat to food security with up to 50% yield losses. Panicle blast is a more severe form of rice blast and the response of rice plant to leaf and panicle blast is distinct in different genotypes. To understand the specific response of rice in panicle blast, transcriptome analysis of blast resistant cultivar Tetep, and susceptible cultivar HP2216 was carried out using RNA-Seq approach after 48, 72 and 96 h of infection with Magnaporthe oryzae along with mock inoculation. Transcriptome data analysis of infected panicle tissues revealed that 3553 genes differentially expressed in HP2216 and 2491 genes in Tetep, which must be the responsible factor behind the differential disease response. The defense responsive genes are involved mainly in defense pathways namely, hormonal regulation, synthesis of reactive oxygen species, secondary metabolites and cell wall modification. The common differentially expressed genes in both the cultivars were defense responsive transcription factors, NBS-LRR genes, kinases, pathogenesis related genes and peroxidases. In Tetep, cell wall strengthening pathway represented by PMR5, dirigent, tubulin, cell wall proteins, chitinases, and proteases was found to be specifically enriched. Additionally, many novel genes having DOMON, VWF, and PCaP1 domains which are specific to cell membrane were highly expressed only in Tetep post infection, suggesting their role in panicle blast resistance. Thus, our study shows that panicle blast resistance is a complex phenomenon contributed by early defense response through ROS production and detoxification, MAPK and LRR signaling, accumulation of antimicrobial compounds and secondary metabolites, and cell wall strengthening to prevent the entry and spread of the fungi. The present investigation provided valuable candidate genes that can unravel the mechanisms of panicle blast resistance and help in the rice blast breeding program.

scholarly journals Norovirus recombination

2007 ◽  
Vol 88 (12) ◽  
pp. 3347-3359 ◽  
Author(s):  
Rowena A. Bull ◽  
Mark M. Tanaka ◽  
Peter A. White
Keyword(s):  
High Frequency ◽  
Driving Force ◽  
Recombination Event ◽  
Viral Evolution ◽  
Rna Recombination ◽  
Recombination Point ◽  
The Family ◽  
Double Recombination ◽  
Double Recombination Event ◽  
Recombination Breakpoints

RNA recombination is a significant driving force in viral evolution. Increased awareness of recombination within the genus Norovirus of the family Calicivirus has led to a rise in the identification of norovirus (NoV) recombinants and they are now reported at high frequency. Currently, there is no classification system for recombinant NoVs and a widely accepted recombinant genotyping system is still needed. Consequently, there is duplication in reporting of novel recombinants. This has led to difficulties in defining the number and types of recombinants in circulation. In this study, 120 NoV nucleotide sequences were compiled from the current GenBank database and published literature. NoV recombinants and their recombination breakpoints were identified using three methods: phylogenetic analysis, SimPlot analysis and the maximum χ 2 method. A total of 20 NoV recombinant types were identified in circulation worldwide. The recombination point is the ORF1/2 overlap in all isolates except one, which demonstrated a double recombination event within the polymerase region.

scholarly journals A novel, multipartite, negative-strand RNA virus is associated with the ringspot disease of European mountain ash (Sorbus aucuparia L.)

2007 ◽  
Vol 88 (4) ◽  
pp. 1337-1346 ◽  
Author(s):  
Nicole Mielke ◽  
Hans-Peter Muehlbach
Keyword(s):  
Rna Virus ◽  
Plant Viruses ◽  
Glycoprotein Precursor ◽  
Structure Comparison ◽  
Viral Rnas ◽  
Pathogenic Virus ◽  
Mountain Ash ◽  
The Family ◽  
European Mountain ◽  
Novel Virus

Four RNAs from a new plant-pathogenic virus, which we have tentatively named European mountain ash ringspot-associated virus (EMARAV), were identified and sequenced completely. All four viral RNAs could be detected in previous double-stranded RNA preparations. RNA 1 (7040 nt) encodes a protein with similarity to the RNA-dependent RNA polymerase of different members of the Bunyaviridae, a family containing five genera with viruses infecting invertebrates, vertebrates and plants. RNA 2 (2335 nt) encodes a 75 kDa protein containing a conserved motif of the glycoprotein precursor of the genus Phlebovirus. Immunological detection indicated the presence of proteins with the expected size of the precursor and one of its processing products. The amino acid sequence of protein p3 (35 kDa) encoded by RNA 3 shows similarities to a putative nucleocapsid protein of two still unclassified plant viruses. The fourth viral RNA encodes a 27 kDa protein that has no significant homology to any known protein. As is typical for members of the family Bunyaviridae, the 5′ and 3′ ends of all viral RNAs are complementary, which allows the RNA to form a panhandle structure. Comparison of these sequences demonstrates a conserved terminal part of 13 nt, similar to that of the bunyaviral genus Orthobunyavirus. Despite the high agreement of the EMARAV genome with several characteristics of the family Bunyaviridae, there are a few features that make it difficult to allocate the virus to this group. It is therefore more likely that this plant pathogen belongs to a novel virus genus.

scholarly journals Tanzawaic acids I–L: Four new polyketides from Penicillium sp. IBWF104-06

2014 ◽  
Vol 10 ◽  
pp. 251-258 ◽  
Author(s):  
Louis P Sandjo ◽  
Eckhard Thines ◽  
Till Opatz ◽  
Anja Schüffler
Keyword(s):  
Soil Sample ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Fungal Strain ◽  
Conidial Germination ◽  
Penicillium Sp ◽  
Culture Filtrates ◽  
Blast Fungus ◽  
New Compounds

Four new polyketides have been identified in culture filtrates of the fungal strain Penicillium sp. IBWF104-06 isolated from a soil sample. They are structurally based on the same trans-decalinpentanoic acid skeleton as tanzawaic acids A–H. One of the new compounds was found to inhibit the conidial germination in the rice blast fungus Magnaporthe oryzae at concentrations of 25 μg/mL.

scholarly journals A Homeobox Gene Is Essential for Conidiogenesis of the Rice Blast Fungus Magnaporthe oryzae

2010 ◽  
Vol 23 (4) ◽  
pp. 366-375 ◽  
Author(s):  
Wende Liu ◽  
Shiyong Xie ◽  
Xinhua Zhao ◽  
Xin Chen ◽  
Wenhui Zheng ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Homeobox Gene ◽  
Gene Replacement ◽  
Fungal Genome ◽  
Protein Signaling ◽  
Homeodomain Proteins ◽  
Conidial Production ◽  
Targeted Gene Replacement ◽  
Severity Of The Disease

Magnaporthe oryzae starts its infection by the attachment of pyriform conidia on rice tissues, and severity of the disease epidemic is proportional to the quantity of conidia produced in the rice blast lesions. However, the mechanism of conidial production is not well understood. Homeodomain proteins play critical roles in regulating various growth and developmental processes in fungi and other eukaryotes. Through targeted gene replacement, we find that deletion of HTF1, one of seven homeobox genes in the fungal genome, does not affect mycelial growth but causes total defect of conidial production. Further observation revealed that the Δhtf1 mutant produces significantly more conidiophores, which curve slightly near the tip but could not develop sterigmata-like structures. Although the Δhtf1 mutant fails to form conidia, it could still develop melanized appressoria from hyphal tips and infect plants. The expression level of HTF1 is significantly reduced in the Δmgb1 G-β and ΔcpkA deletion mutant, and the ACR1 but not CON7 gene that encodes transcription factor required for normal conidiogenesis is significantly downregulated in the Δhtf1 mutant. These data suggest that the HTF1 gene is essential for conidiogenesis, and may be functionally related to the trimeric G-protein signaling and other transcriptional regulators that are known to be important for conidiation in M. oryzae.

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