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 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 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.

scholarly journals Septin-Mediated Plant Cell Invasion by the Rice Blast Fungus, Magnaporthe oryzae

Science ◽  
2012 ◽  
Vol 336 (6088) ◽  
pp. 1590-1595 ◽  
Author(s):  
Y. F. Dagdas ◽  
K. Yoshino ◽  
G. Dagdas ◽  
L. S. Ryder ◽  
E. Bielska ◽  
...  
Keyword(s):  
Plant Cell ◽  
Cell Invasion ◽  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Blast Fungus

scholarly journals Osa-miR162a balances rice yield and resistance to Magnaporthe oryzae

2020 ◽  
Author(s):  
Xu-Pu Li ◽  
Xiao-Chun Ma ◽  
He Wang ◽  
Yong Zhu ◽  
Xin-Xian Liu ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Yield ◽  
Blast Resistance ◽  
Blast Disease ◽  
Mirna Biogenesis ◽  
Trade Off ◽  
Rice Blast Resistance ◽  
Defense Related Gene ◽  
Transgenic Lines

Abstract MicroRNAs (miRNAs) play essential roles in rice immunity against Magnaporthe oryzae, the causative agent of rice blast disease. Osa-miR162a targets Dicer-like 1 (DCL1) genes, which play vital roles in miRNA biogenesis and act as negative regulators in rice immunity. Here we demonstrate that Osa-miR162a improves rice immunity against M. oryzae and balances the trade-off between rice yield and resistance. Overexpression of Osa-miR162a compromises rice susceptibility to M. oryzae accompanying enhanced induction of defense-related genes and accumulation of hydrogen peroxide (H2O2). In contrast, blocking miR162 by overexpressing a target mimic of miR162 enhances susceptibility to blast fungus associating with compromised induction of defense-related gene expression and H2O2 accumulation. Moreover, the transgenic lines overexpressing Osa-miR162a display decreased seed setting rate resulting in reduced yield per plant, whereas blocking miR162 leads to an increased number of grains per panicle, resulting in increased yield per plant. Altered accumulation of miR162 had limited impact on the expression of OsDCL1. Together, our results indicate that Osa-miR162a improves rice blast resistance and plays a role in the balance of trade-off between resistance and yield.

scholarly journals Genome-wide polyadenylation site mapping datasets in the rice blast fungus Magnaporthe oryzae

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Marco Marconi ◽  
Ane Sesma ◽  
Julio Luis Rodríguez-Romero ◽  
María Lourdes Rosano González ◽  
Mark D. Wilkinson
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Polyadenylation Site ◽  
Blast Fungus ◽  
Site Mapping ◽  
Genome Wide

scholarly journals Role of two metacaspases in development and pathogenicity of the Rice Blast fungus, Magnaporthe oryzae

2020 ◽  
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 ◽  
Insight Into

ABSTRACTRice 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 are able to 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 increase 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.IMPORTANCEMagnaporthe 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 remains 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 insight 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.

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