scholarly journals Cellular Dynamics and Genomic Identity of Centromeres in Cereal Blast Fungus

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Vikas Yadav ◽  
Fan Yang ◽  
Md. Hashim Reza ◽  
Sanzhen Liu ◽  
Barbara Valent ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Chromosome Segregation ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Metaphase Plate ◽  
Blast Disease ◽  
Sequence Motifs ◽  
Content Type ◽  
Kinetochore Assembly ◽  
Blast Fungus

ABSTRACT Precise kinetochore-microtubule interactions ensure faithful chromosome segregation in eukaryotes. Centromeres, identified as scaffolding sites for kinetochore assembly, are among the most rapidly evolving chromosomal loci in terms of the DNA sequence and length and organization of intrinsic elements. Neither the centromere structure nor the kinetochore dynamics is well studied in plant-pathogenic fungi. Here, we sought to understand the process of chromosome segregation in the rice blast fungus Magnaporthe oryzae. High-resolution imaging of green fluorescent protein (GFP)-tagged inner kinetochore proteins CenpA and CenpC revealed unusual albeit transient declustering of centromeres just before anaphase separation of chromosomes in M. oryzae. Strikingly, the declustered centromeres positioned randomly at the spindle midzone without an apparent metaphase plate per se. Using CenpA chromatin immunoprecipitation followed by deep sequencing, all seven centromeres in M. oryzae were found to be regional, spanning 57-kb to 109-kb transcriptionally poor regions. Highly AT-rich and heavily methylated DNA sequences were the only common defining features of all the centromeres in rice blast. Lack of centromere-specific DNA sequence motifs or repetitive elements suggests an epigenetic specification of centromere function in M. oryzae. PacBio genome assemblies and synteny analyses facilitated comparison of the centromeric/pericentromeric regions in distinct isolates of rice blast and wheat blast and in Magnaporthiopsis poae. Overall, this study revealed unusual centromere dynamics and precisely identified the centromere loci in the top model fungal pathogens that belong to Magnaporthales and cause severe losses in the global production of food crops and turf grasses. IMPORTANCE Magnaporthe oryzae is an important fungal pathogen that causes a loss of 10% to 30% of the annual rice crop due to the devastating blast disease. In most organisms, kinetochores are clustered together or arranged at the metaphase plate to facilitate synchronized anaphase separation of sister chromatids in mitosis. In this study, we showed that the initially clustered kinetochores separate and position randomly prior to anaphase in M. oryzae. Centromeres in M. oryzae occupy large genomic regions and form on AT-rich DNA without any common sequence motifs. Overall, this study identified atypical kinetochore dynamics and mapped functional centromeres in M. oryzae to define the roles of centromeric and pericentric boundaries in kinetochore assembly on epigenetically specified centromere loci. This study should pave the way for further understanding of the contribution of heterochromatin in genome stability and virulence of the blast fungus and its related species of high economic importance.

scholarly journals Cellular Dynamics and Genomic Identity of Centromeres in the Cereal Blast Fungus

2018 ◽  
Author(s):  
Vikas Yadav ◽  
Fan Yang ◽  
Md. Hashim Reza ◽  
Sanzhen Liu ◽  
Barbara Valent ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Chromosome Segregation ◽  
Magnaporthe Oryzae ◽  
Dna Sequences ◽  
Rice Blast ◽  
Metaphase Plate ◽  
Rice Blast Fungus ◽  
Kinetochore Assembly ◽  
Blast Fungus ◽  
The Way

AbstractA series of well-synchronized events mediated by kinetochore-microtubule interactions ensure faithful chromosome segregation in eukaryotes. Centromeres scaffold kinetochore assembly and are among the fastest evolving chromosomal loci in terms of the DNA sequence, length, and organization of intrinsic elements. Neither the centromere structure nor the kinetochore dynamics is well studied in plant pathogenic fungi. Here, we sought to understand the process of chromosome segregation in the rice blast fungus, Magnaporthe oryzae. High-resolution confocal imaging of GFP-tagged inner kinetochore proteins, CenpA and CenpC, revealed an unusual albeit transient declustering of centromeres just before anaphase separation in M. oryzae. Strikingly, the declustered centromeres positioned randomly at the spindle midzone without an apparent metaphase plate per se. Using chromatin immunoprecipitation followed by deep sequencing, all seven centromeres were identified as CenpA-rich regions in the wild-type Guy11 strain of M. oryzae. The centromeres in M. oryzae are regional and span 57 to 109 kb transcriptionally poor regions. No centromere-specific DNA sequence motif or repetitive elements could be identified in these regions suggesting an epigenetic specification of centromere function in M. oryzae. Highly AT-rich and heavily methylated DNA sequences were the only common defining features of all the centromeres in rice blast fungus. PacBio genome assemblies and synteny analyses facilitated comparison of the centromere regions in distinct isolate(s) of rice blast, wheat blast, and in M. poae. Overall, this study identified unusual centromere dynamics and precisely mapped the centromere DNA sequences in the top model fungal pathogens that belong to the Magnaporthales and cause severe losses to global production of food crops and turf grasses.Author summaryMagnaporthe oryzae is an important fungal pathogen that causes an annual loss of 10-30% of the rice crop due to the devastating blast disease. In most organisms, kinetochores are arranged either in the metaphase plate or are clustered together to facilitate synchronized anaphase separation of chromosomes. In this study, we show that the initially clustered kinetochores separate and position randomly prior to anaphase in M. oryzae. Centromeres, identified as the site of kinetochore assembly, are regional type without any shared sequence motifs in M. oryzae. Together, this study reveals atypical kinetochore dynamics and identifies functional centromeres in M. oryzae, thus paving the way to define heterochromatin boundaries and understand the process of kinetochore assembly on epigenetically specified centromere loci in the economically important cereal blast and summer patch pathogens. This study paves the way for understanding the contribution of heterochromatin in genome stability and virulence of the blast fungus.

scholarly journals The mitotic spindle mediates nuclear migration through an extremely narrow infection structure of the rice blast fungus Magnaporthe oryzae

2021 ◽  
Author(s):  
Mariel A. Pfeifer ◽  
Chang Hyun Khang
Keyword(s):  
Magnaporthe Oryzae ◽  
Mitotic Spindle ◽  
Rice Blast ◽  
Mechanistic Model ◽  
Nuclear Migration ◽  
Blast Disease ◽  
Cellular Structures ◽  
Blast Fungus ◽  
Single Nucleus ◽  
Migration Event

The blast fungus, Magnaporthe oryzae, causes severe destruction to rice and other crops worldwide. As the fungus infects rice, it develops unique cellular structures, such as an appressorium and a narrow penetration peg, to permit successful invasion of host rice cells. Fundamental knowledge about these cellular structures and how organelles, such as the nucleus, are positioned within them is still emerging. Previous studies show that a single nucleus becomes highly stretched during movement through the narrow penetration peg in an extreme nuclear migration event. Yet, the mechanism permitting this nuclear migration event remains elusive. Here, we investigate the role of the mitotic spindle in mediating nuclear migration through the penetration peg. We find that disruption of spindle function during nuclear migration through the penetration peg prevents development of invasive hyphae and virulence on rice. Furthermore, regulated expression of conserved kinesin motor proteins, MoKin5 and MoKin14, is essential to form and maintain the spindle, as well as, properly nucleate the primary hypha. Overexpression of MoKin5 leads to formation of aberrant microtubule protrusions, which contributes to formation of nuclear fragments within the appressorium and primary hypha. Conversely, overexpression of MoKin14 causes the spindle to collapse leading to the formation of monopolar spindles. These results establish a mechanistic model towards understanding the intricate subcellular dynamics of extreme nuclear migration through the penetration peg, a critical step in the development of rice blast disease.

scholarly journals Role of Two Metacaspases in Development and Pathogenicity of the Rice Blast Fungus Magnaporthe oryzae

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jessie Fernandez ◽  
Victor Lopez ◽  
Lisa Kinch ◽  
Mariel A. Pfeifer ◽  
Hillery Gray ◽  
...  
Keyword(s):  
Cell Death ◽  
Food Security ◽  
Life Cycle ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Complex Life Cycle ◽  
Content Type

ABSTRACT Rice blast disease caused by Magnaporthe oryzae is a devastating disease of cultivated rice worldwide. Infections by this fungus lead to a significant reduction in rice yields and threats to food security. To gain better insight into growth and cell death in M. oryzae during infection, we characterized two predicted M. oryzae metacaspase proteins, MoMca1 and MoMca2. These proteins appear to be functionally redundant and can complement the yeast Yca1 homologue. Biochemical analysis revealed that M. oryzae metacaspases exhibited Ca2+-dependent caspase activity in vitro. Deletion of both MoMca1 and MoMca2 in M. oryzae resulted in reduced sporulation, delay in conidial germination, and attenuation of disease severity. In addition, the double ΔMomca1mca2 mutant strain showed increased radial growth in the presence of oxidative stress. Interestingly, the ΔMomca1mca2 strain showed an increased accumulation of insoluble aggregates compared to the wild-type strain during vegetative growth. Our findings suggest that MoMca1 and MoMca2 promote the clearance of insoluble aggregates in M. oryzae, demonstrating the important role these metacaspases have in fungal protein homeostasis. Furthermore, these metacaspase proteins may play additional roles, like in regulating stress responses, that would help maintain the fitness of fungal cells required for host infection. IMPORTANCE Magnaporthe oryzae causes rice blast disease that threatens global food security by resulting in the severe loss of rice production every year. A tightly regulated life cycle allows M. oryzae to disarm the host plant immune system during its biotrophic stage before triggering plant cell death in its necrotrophic stage. The ways M. oryzae navigates its complex life cycle remain unclear. This work characterizes two metacaspase proteins with peptidase activity in M. oryzae that are shown to be involved in the regulation of fungal growth and development prior to infection by potentially helping maintain fungal fitness. This study provides new insights into the role of metacaspase proteins in filamentous fungi by illustrating the delays in M. oryzae morphogenesis in the absence of these proteins. Understanding the mechanisms by which M. oryzae morphology and development promote its devastating pathogenicity may lead to the emergence of proper methods for disease control.

scholarly journals System-Wide Characterization of MoArf GTPase Family Proteins and Adaptor Protein MoGga1 Involved in the Development and Pathogenicity of Magnaporthe oryzae

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Shengpei Zhang ◽  
Lina Yang ◽  
Lianwei Li ◽  
Kaili Zhong ◽  
Wenhao Wang ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Vesicle Trafficking ◽  
Family Members ◽  
Adaptor Protein ◽  
Small Gtpase ◽  
Content Type ◽  
Blast Fungus ◽  
Adp Ribosylation Factor

ABSTRACT ADP ribosylation factor (Arf) small GTPase family members are involved in vesicle trafficking and organelle maintenance in organisms ranging from Saccharomyces cerevisiae to humans. A previous study identified Magnaporthe oryzae Arf6 (MoArf6) as one of the Arf proteins that regulates growth and conidiation in the rice blast fungus M. oryzae, but the remaining family proteins remain unknown. Here, we identified six additional Arf proteins, including MoArf1, MoArl1, MoArl3, MoArl8, MoCin4, and MoSar1, as well as their sole adaptor protein, MoGga1, and determined their shared and specific functions. We showed that the majority of these proteins exhibit positive regulatory functions, most notably, in growth. Importantly, MoArl1, MoCin4, and MoGga1 are involved in pathogenicity through the regulation of host penetration and invasive hyphal growth. MoArl1 and MoCin4 also regulate normal vesicle trafficking, and MoCin4 further controls the formation of the biotrophic interfacial complex (BIC). Moreover, we showed that Golgi-cytoplasm cycling of MoArl1 is required for its function. Finally, we demonstrated that interactions between MoArf1 and MoArl1 with MoGga1 are important for Golgi localization and pathogenicity. Collectively, our findings revealed the shared and specific functions of Arf family members in M. oryzae and shed light on how these proteins function through conserved mechanisms to govern growth, transport, and virulence of the blast fungus. IMPORTANCE Magnaporthe oryzae is the causal agent of rice blast, representing the most devastating diseases of rice worldwide, which results in losses of amounts of rice that could feed more than 60 million people each year. Arf (ADP ribosylation factor) small GTPase family proteins are involved in vesicle trafficking and organelle maintenance in eukaryotic cells. To investigate the function of Arf family proteins in M. oryzae, we systematically characterized all seven Arf proteins and found that they have shared and specific functions in governing the growth, development, and pathogenicity of the blast fungus. We have also identified the pathogenicity-related protein MoGga1 as the common adaptor of MoArf1 and MoArl1. Our findings are important because they provide the first comprehensive characterization of the Arf GTPase family proteins and their adaptor protein MoGga1 functioning in a plant-pathogenic fungus, which could help to reveal new fungicide targets to control this devastating disease.

scholarly journals The Histone Deacetylases MoRpd3 and MoHst4 Regulate Growth, Conidiation, and Pathogenicity in the Rice Blast Fungus Magnaporthe oryzae

mSphere ◽  
2021 ◽  
Author(s):  
Chaoxiang Lin ◽  
Xue Cao ◽  
Ziwei Qu ◽  
Shulin Zhang ◽  
Naweed I. Naqvi ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Histone Deacetylases ◽  
Rice Blast ◽  
Pathogenic Fungi ◽  
Rice Blast Fungus ◽  
Plant Pathogenic Fungi ◽  
Content Type ◽  
Blast Fungus ◽  
Growth Development

HDACs (histone deacetylases) regulate various aspects of growth, development, and pathogenesis in plant-pathogenic fungi. Most members of HDAC classes I to III have been functionally characterized, except for orthologous Rpd3 and Hst4, in the rice blast fungus Magnaporthe oryzae .

scholarly journals Genetic Variation Bias toward Noncoding Regions and Secreted Proteins in the Rice Blast Fungus Magnaporthe oryzae

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Zhenhui Zhong ◽  
Meilian Chen ◽  
Lianyu Lin ◽  
Ruiqi Chen ◽  
Dan Liu ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Magnaporthe Oryzae ◽  
Experimental Evolution ◽  
Rice Blast ◽  
Plant Pathogens ◽  
Rice Blast Fungus ◽  
Content Type ◽  
Noncoding Regions ◽  
Blast Fungus ◽  
Pathogen Populations

ABSTRACT The genomes of plant pathogens are highly variable and plastic. Pathogen gene repertoires change quickly with the plant environment, which results in a rapid loss of plant resistance shortly after the pathogen emerges in the field. Extensive studies have evaluated natural pathogen populations to understand their evolutionary effects; however, the number of studies that have examined the dynamic processes of the mutation and adaptation of plant pathogens to host plants remains limited. Here, we applied experimental evolution and high-throughput pool sequencing to Magnaporthe oryzae, a fungal pathogen that causes massive losses in rice production, to observe the evolution of genome variation. We found that mutations, including single-nucleotide variants (SNVs), insertions and deletions (indels), and transposable element (TE) insertions, accumulated very rapidly throughout the genome of M. oryzae during sequential plant inoculation and preferentially in noncoding regions, while such mutations were not frequently found in coding regions. However, we also observed that new TE insertions accumulated with time and preferentially accumulated at the proximal region of secreted protein (SP) coding genes in M. oryzae populations. Taken together, these results revealed a bias in genetic variation toward noncoding regions and SP genes in M. oryzae and may contribute to the rapid adaptive evolution of the blast fungal effectors under host selection. IMPORTANCE Plants “lose” resistance toward pathogens shortly after their widespread emergence in the field because plant pathogens mutate and adapt rapidly under resistance selection. Thus, the rapid evolution of pathogens is a serious threat to plant health. Extensive studies have evaluated natural pathogen populations to understand their evolutionary effects; however, the study of the dynamic processes of the mutation and adaptation of plant pathogens to host plants remains limited. Here, by performing an experimental evolution study, we found a bias in genetic variation toward noncoding regions and SPs in the rice blast fungus Magnaporthe oryzae, which explains the ability of the rice blast fungus to maintain high virulence variation to overcome rice resistance in the field.

scholarly journals A Histone Deacetylase, Magnaporthe oryzae RPD3, Regulates Reproduction and Pathogenic Development in the Rice Blast Fungus

mBio ◽  
2021 ◽  
Author(s):  
Song Hee Lee ◽  
Mohamed El-Agamy Farh ◽  
Jaejoon Lee ◽  
Young Taek Oh ◽  
Eunbyeol Cho ◽  
...  
Keyword(s):  
Histone Deacetylase ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Fungal Pathogens ◽  
Blast Disease ◽  
Gene Encoding ◽  
Content Type ◽  
Cellular Processes ◽  
Evolutionarily Conserved ◽  
Severe Growth

RPD3 is an evolutionarily conserved class I histone deacetylase (HDAC) that plays a pivotal role in diverse cellular processes. In filamentous fungal pathogens, abrogation of the gene encoding RPD3 results in either lethality or severe growth impairment, making subsequent genetic analyses challenging. Magnaporthe oryzae is a causal agent of rice blast disease, which is responsible for significant annual yield losses in rice production.

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 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 Long Non-coding RNAs Responsive to Blast Fungus Infection in Rice

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Lan-Lan Wang ◽  
Jing-Jing Jin ◽  
Li-Hua Li ◽  
Shao-Hong Qu
Keyword(s):  
Rice Blast ◽  
Blast Resistance ◽  
Enrichment Analysis ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Blast Disease ◽  
Fungus Infection ◽  
Blast Fungus ◽  
Gene Transcription Level ◽  
Non Coding Rnas

Abstract Background Long non-coding RNAs (LncRNAs) have emerged as important regulators in many physiological processes in plant. By high-throughput RNA-sequencing, many pathogen-associated LncRNAs were mapped in various plants, and some of them were proved to be involved in plant defense responses. The rice blast disease caused by Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases in rice. However, M. oryzae-induced LncRNAs in rice is yet to be studied. Findings We investigated rice LncRNAs that were associated with the rice blast fungus. Totally 83 LncRNAs were up-regulated after blast fungus infection and 78 were down-regulated. Of them, the natural antisense transcripts (NATs) were the most abundant. The expression of some LncRNAs has similar pattern with their host genes or neighboring genes, suggesting a cis function of them in regulating gene transcription level. The deferentially expressed (DE) LncRNAs and genes co-expression analysis revealed some LncRNAs were associated with genes known to be involved in pathogen resistance, and these genes were enriched in terpenoid biosynthesis and defense response by Gene Ontology (GO) enrichment analysis. Interestingly, one of up-regulated DE-intronic RNA was derived from a jasmonate (JA) biosynthetic gene, lipoxygenase RLL (LOX-RLL). Levels of JAs were significantly increased after blast fungus infection. Given that JA is known to regulate blast resistance in rice, we suggested that LncRNA may be involved in JA-mediated rice resistance to blast fungus. Conclusions This study identified blast fungus-responsive LncRNAs in rice, which provides another layer of candidates that regulate rice and blast fungus interactions.

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