The appressorium of Magnaporthe oryzae remains mitotically active during post-penetration hyphal growth in rice cells

2016 ◽  
Author(s):  
Kiersun Jones ◽  
Cory B. Jenkinson ◽  
Jie Zhu ◽  
Sara Dorhmi ◽  
Chang Hyun Khang

AbstractTo investigate the mitotic dynamics of an appressorium, we used time-lapse confocal imaging of a fluorescence-based mitotic reporter strain of Magnaporthe oryzae. We present evidence that: (i) appressoria remain viable and mitotically active after host penetration, (ii) appressorial mitosis, like invasive hyphal mitosis, is semi-closed, (iii) sister chromatids separate within the appressorium, (iv) a mitotic appressorial nucleus undergoes extreme constriction and elongation as it migrates through the penetration peg in a manner analogous to mitosis during cell-to-cell movement of invasive hyphae. These results provide new insight into the potential roles of the appressorium after host penetration and highlight the unique mitotic dynamics during rice blast infection.

2020 ◽  
Author(s):  
Jessie Fernandez ◽  
Victor Lopez ◽  
Lisa Kinch ◽  
Mariel A. Pfeifer ◽  
Hillery Gray ◽  
...  

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.


2017 ◽  
Vol 98 ◽  
pp. 35-38 ◽  
Author(s):  
Cory B. Jenkinson ◽  
Kiersun Jones ◽  
Jie Zhu ◽  
Sara Dorhmi ◽  
Chang Hyun Khang

2011 ◽  
Vol 48 (8) ◽  
pp. 784-792 ◽  
Author(s):  
Jaeduk Goh ◽  
Kyoung Su Kim ◽  
Jaejin Park ◽  
Junhyun Jeon ◽  
Sook-Young Park ◽  
...  

2008 ◽  
Vol 9 (5) ◽  
pp. R85 ◽  
Author(s):  
Yeonyee Oh ◽  
Nicole Donofrio ◽  
Huaqin Pan ◽  
Sean Coughlan ◽  
Douglas E Brown ◽  
...  

2021 ◽  
pp. 103562
Author(s):  
Alice Bisola Eseola ◽  
Lauren S. Ryder ◽  
Míriam Osés-Ruiz ◽  
Kim Findlay ◽  
Xia Yan ◽  
...  

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 301
Author(s):  
Vishesh Kumar ◽  
Priyanka Jain ◽  
Sureshkumar Venkadesan ◽  
Suhas Gorakh Karkute ◽  
Jyotika Bhati ◽  
...  

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.


2004 ◽  
Vol 15 (10) ◽  
pp. 4622-4632 ◽  
Author(s):  
Yasmina Bauer ◽  
Philipp Knechtle ◽  
Jürgen Wendland ◽  
Hanspeter Helfer ◽  
Peter Philippsen

Characteristic features of morphogenesis in filamentous fungi are sustained polar growth at tips of hyphae and frequent initiation of novel growth sites (branches) along the extending hyphae. We have begun to study regulation of this process on the molecular level by using the model fungus Ashbya gossypii. We found that the A. gossypii Ras-like GTPase Rsr1p/Bud1p localizes to the tip region and that it is involved in apical polarization of the actin cytoskeleton, a determinant of growth direction. In the absence of RSR1/BUD1, hyphal growth was severely slowed down due to frequent phases of pausing of growth at the hyphal tip. During pausing events a hyphal tip marker, encoded by the polarisome component AgSPA2, disappeared from the tip as was shown by in vivo time-lapse fluorescence microscopy of green fluorescent protein-labeled AgSpa2p. Reoccurrence of AgSpa2p was required for the resumption of hyphal growth. In the Agrsr1/bud1Δ deletion mutant, resumption of growth occurred at the hyphal tip in a frequently uncoordinated manner to the previous axis of polarity. Additionally, hyphal filaments in the mutant developed aberrant branching sites by mislocalizing AgSpa2p thus distorting hyphal morphology. These results define AgRsr1p/Bud1p as a key regulator of hyphal growth guidance.


2011 ◽  
Vol 6 (11) ◽  
pp. 1792-1805 ◽  
Author(s):  
Jean-Charles Boisset ◽  
Charlotte Andrieu-Soler ◽  
Wiggert A van Cappellen ◽  
Thomas Clapes ◽  
Catherine Robin

2014 ◽  
Vol 10 ◽  
pp. 251-258 ◽  
Author(s):  
Louis P Sandjo ◽  
Eckhard Thines ◽  
Till Opatz ◽  
Anja Schüffler

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.


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