The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Daniel J. Ebbole - One of the best experts on this subject based on the ideXlab platform.
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Table_1_Magnaporthe oryzae CK2 Accumulates in Nuclei, Nucleoli, at Septal Pores and Forms a Large Ring Structure in Appressoria, and Is Involved in Rice Blast Pathogenesis.docx
2019Co-Authors: Lianhu Zhang, Daniel J. Ebbole, Dongmei Zhang, Yunyun Chen, Qingyun Lin, Stefan Olsson, Zonghua WangAbstract:Magnaporthe oryzae (Mo) is a model pathogen causing rice blast resulting in yield and economic losses world-wide. CK2 is a constitutively active, serine/threonine kinase in eukaryotes, having a wide array of known substrates, and involved in many cellular processes. We investigated the localization and role of MoCK2 during growth and infection. BLAST search for MoCK2 components and targeted deletion of subunits was combined with protein-GFP fusions to investigate localization. We found one CKa and two CKb subunits of the CK2 holoenzyme. Deletion of the catalytic subunit CKa was not possible and might indicate that such deletions are lethal. The CKb subunits could be deleted but they were both necessary for normal growth and pathogenicity. Localization studies showed that the CK2 holoenzyme needed to be intact for normal localization at septal pores and at appressorium penetration pores. Nuclear localization of CKa was however not dependent on the intact CK2 holoenzyme. In Appressoria, CK2 formed a large ring perpendicular to the penetration pore and the ring formation was dependent on the presence of all CK2 subunits. The effects on growth and pathogenicity of deletion of the b subunits combined with the localization indicate that CK2 can have important regulatory functions not only in the nucleus/nucleolus but also at fungal specific structures such as septa and Appressorial pores.
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Video_5_Magnaporthe oryzae CK2 Accumulates in Nuclei, Nucleoli, at Septal Pores and Forms a Large Ring Structure in Appressoria, and Is Involved in Rice Blast Pathogenesis.AVI
2019Co-Authors: Lianhu Zhang, Daniel J. Ebbole, Dongmei Zhang, Yunyun Chen, Qingyun Lin, Stefan Olsson, Zonghua WangAbstract:Magnaporthe oryzae (Mo) is a model pathogen causing rice blast resulting in yield and economic losses world-wide. CK2 is a constitutively active, serine/threonine kinase in eukaryotes, having a wide array of known substrates, and involved in many cellular processes. We investigated the localization and role of MoCK2 during growth and infection. BLAST search for MoCK2 components and targeted deletion of subunits was combined with protein-GFP fusions to investigate localization. We found one CKa and two CKb subunits of the CK2 holoenzyme. Deletion of the catalytic subunit CKa was not possible and might indicate that such deletions are lethal. The CKb subunits could be deleted but they were both necessary for normal growth and pathogenicity. Localization studies showed that the CK2 holoenzyme needed to be intact for normal localization at septal pores and at appressorium penetration pores. Nuclear localization of CKa was however not dependent on the intact CK2 holoenzyme. In Appressoria, CK2 formed a large ring perpendicular to the penetration pore and the ring formation was dependent on the presence of all CK2 subunits. The effects on growth and pathogenicity of deletion of the b subunits combined with the localization indicate that CK2 can have important regulatory functions not only in the nucleus/nucleolus but also at fungal specific structures such as septa and Appressorial pores.
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Image_1_Magnaporthe oryzae CK2 Accumulates in Nuclei, Nucleoli, at Septal Pores and Forms a Large Ring Structure in Appressoria, and Is Involved in Rice Blast Pathogenesis.TIFF
2019Co-Authors: Lianhu Zhang, Daniel J. Ebbole, Dongmei Zhang, Yunyun Chen, Qingyun Lin, Stefan Olsson, Zonghua WangAbstract:Magnaporthe oryzae (Mo) is a model pathogen causing rice blast resulting in yield and economic losses world-wide. CK2 is a constitutively active, serine/threonine kinase in eukaryotes, having a wide array of known substrates, and involved in many cellular processes. We investigated the localization and role of MoCK2 during growth and infection. BLAST search for MoCK2 components and targeted deletion of subunits was combined with protein-GFP fusions to investigate localization. We found one CKa and two CKb subunits of the CK2 holoenzyme. Deletion of the catalytic subunit CKa was not possible and might indicate that such deletions are lethal. The CKb subunits could be deleted but they were both necessary for normal growth and pathogenicity. Localization studies showed that the CK2 holoenzyme needed to be intact for normal localization at septal pores and at appressorium penetration pores. Nuclear localization of CKa was however not dependent on the intact CK2 holoenzyme. In Appressoria, CK2 formed a large ring perpendicular to the penetration pore and the ring formation was dependent on the presence of all CK2 subunits. The effects on growth and pathogenicity of deletion of the b subunits combined with the localization indicate that CK2 can have important regulatory functions not only in the nucleus/nucleolus but also at fungal specific structures such as septa and Appressorial pores.
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Magnaporthe oryzae CK2 Accumulates in Nuclei, Nucleoli, at Septal Pores and Forms a Large Ring Structure in Appressoria, and Is Involved in Rice Blast Pathogenesis
Frontiers Media S.A., 2019Co-Authors: Lianhu Zhang, Daniel J. Ebbole, Dongmei Zhang, Yunyun Chen, Qingyun Lin, Stefan OlssonAbstract:Magnaporthe oryzae (Mo) is a model pathogen causing rice blast resulting in yield and economic losses world-wide. CK2 is a constitutively active, serine/threonine kinase in eukaryotes, having a wide array of known substrates, and involved in many cellular processes. We investigated the localization and role of MoCK2 during growth and infection. BLAST search for MoCK2 components and targeted deletion of subunits was combined with protein-GFP fusions to investigate localization. We found one CKa and two CKb subunits of the CK2 holoenzyme. Deletion of the catalytic subunit CKa was not possible and might indicate that such deletions are lethal. The CKb subunits could be deleted but they were both necessary for normal growth and pathogenicity. Localization studies showed that the CK2 holoenzyme needed to be intact for normal localization at septal pores and at appressorium penetration pores. Nuclear localization of CKa was however not dependent on the intact CK2 holoenzyme. In Appressoria, CK2 formed a large ring perpendicular to the penetration pore and the ring formation was dependent on the presence of all CK2 subunits. The effects on growth and pathogenicity of deletion of the b subunits combined with the localization indicate that CK2 can have important regulatory functions not only in the nucleus/nucleolus but also at fungal specific structures such as septa and Appressorial pores
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magnaporthe oryzae ck2 is involved in rice blast pathogenesis and accumulates in nuclei nucleoli at septal and Appressoria pores and forms a large ring structure in Appressoria
bioRxiv, 2018Co-Authors: Lianhu Zhang, Daniel J. Ebbole, Dongmei Zhang, Yunyun Chen, Qingyun Lin, Stefan Olsson, Zonghua WangAbstract:ABSTRACT Magnaporthe oryzae (Mo) is a model pathogen causing rice blast resulting in yield and economic losses world-wide. CK2 is a constitutively active, serine/threonine kinase in eukaryotes, having a wide array of known substrates and involved in many cellular processes. We investigated the localization and role of MoCK2 during growth and infection. BLAST search for MoCK2 components and targeted deletion of subunits was combined with protein-GFP fusions to investigate localization. We found one CKa and two CKb subunits of the CK2 holoenzyme. Deletion of the catalytic subunit CKa was not possible and might indicate that such deletions are lethal. The CKb subunits could be deleted but they were both necessary for normal growth and pathogenicity. Localization studies showed that the CK2 holoenzyme needed to be intact for normal localization at septal pores and at appressorium penetration pores. Nuclear localization of CKa was however not dependent on the intact CK2 holoenzyme. In Appressoria, CK2 formed a large ring perpendicular to the penetration pore and the ring formation was dependent on the presence of all CK2 subunits. The effects on growth and pathogenicity of deletion of the b subunits combined with the localization indicate that CK2 can have important regulatory functions not only in the nucleus/nucleolus but also at fungal specific structures as septa and Appressorial pores.
Richard A. Wilson - One of the best experts on this subject based on the ideXlab platform.
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Spermine-mediated tight sealing of the Magnaporthe oryzae Appressorial pore–rice leaf surface interface
Nature Microbiology, 2020Co-Authors: Raquel O. Rocha, Christian Elowsky, Ngoc T. T. Pham, Richard A. WilsonAbstract:Cellular adhesion mediates many important plant–microbe interactions. In the devastating blast fungus Magnaporthe oryzae ^ 1 , powerful glycoprotein-rich mucilage adhesives^ 2 cement melanized and pressurized dome-shaped infection cells—Appressoria—to host rice leaf surfaces. Enormous internal turgor pressure is directed onto a penetration peg emerging from the unmelanized, thin-walled pore at the Appressorial base^ 1 – 4 , forcing it through the leaf cuticle where it elongates invasive hyphae in underlying epidermal cells^ 5 . Mucilage sealing around the Appressorial pore facilitates turgor build-up^ 2 , but the molecular underpinnings of mucilage secretion and Appressorial adhesion are unknown. Here, we discovered an unanticipated and sole role for spermine in facilitating mucilage production by mitigating endoplasmic reticulum (ER) stress in the developing appressorium. Mutant strains lacking the spermine synthase-encoding gene SPS1 progressed through all stages of Appressorial development, including penetration peg formation, but cuticle penetration was unsuccessful due to reduced Appressorial adhesion, which led to solute leakage. Mechanistically, spermine neutralized off-target oxygen free radicals produced by NADPH oxidase-1 (Nox1)^ 3 , 6 that otherwise elicited ER stress and the unfolded protein response, thereby critically reducing mucilage secretion. Our study reveals that spermine metabolism via redox buffering of the ER underpins Appressorial adhesion and rice cell invasion and provides insights into a process that is fundamental to host plant infection. Spermine facilitates mucilage production and rice cell invasion by mitigating endoplasmic reticulum stress in the developing Magnaporthe oryzae appressorium.
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gata dependent glutaminolysis drives appressorium formation in magnaporthe oryzae by suppressing tor inhibition of camp pka signaling
PLOS Pathogens, 2015Co-Authors: Margarita Marroquinguzman, Richard A. WilsonAbstract:Fungal plant pathogens are persistent and global food security threats. To invade their hosts they often form highly specialized infection structures, known as Appressoria. The cAMP/ PKA- and MAP kinase-signaling cascades have been functionally delineated as positive-acting pathways required for appressorium development. Negative-acting regulatory pathways that block Appressorial development are not known. Here, we present the first detailed evidence that the conserved Target of Rapamycin (TOR) signaling pathway is a powerful inhibitor of appressorium formation by the rice blast fungus Magnaporthe oryzae. We determined TOR signaling was activated in an M. oryzae mutant strain lacking a functional copy of the GATA transcription factor-encoding gene ASD4. Δasd4 mutant strains could not form Appressoria and expressed GLN1, a glutamine synthetase-encoding orthologue silenced in wild type. Inappropriate expression of GLN1 increased the intracellular steady-state levels of glutamine in Δasd4 mutant strains during axenic growth when compared to wild type. Deleting GLN1 lowered glutamine levels and promoted appressorium formation by Δasd4 strains. Furthermore, glutamine is an agonist of TOR. Treating Δasd4 mutant strains with the specific TOR kinase inhibitor rapamycin restored appressorium development. Rapamycin was also shown to induce appressorium formation by wild type and Δcpka mutant strains on non-inductive hydrophilic surfaces but had no effect on the MAP kinase mutant Δpmk1. When taken together, we implicate Asd4 in regulating intracellular glutamine levels in order to modulate TOR inhibition of appressorium formation downstream of cPKA. This study thus provides novel insight into the metabolic mechanisms that underpin the highly regulated process of appressorium development.
Pedro Talhinhas - One of the best experts on this subject based on the ideXlab platform.
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A method for obtaining RNA from Hemileia vastatrix Appressoria produced in planta, suitable for transcriptomic analyses.
Fungal Biology, 2015Co-Authors: Andreia Loureiro, Maria Do Céu Silva, Helena Gil Azinheira, Pedro TalhinhasAbstract:Appressoria are the first infection structures developed by rust fungi and require specific topographic signals from the host for their differentiation. The ease in obtaining Appressoria in vitro for these biotrophic fungi led to studies concerning gene expression and gene discovery at Appressorial level, avoiding the need to distinguish plant and fungal transcripts. However, in some pathosystems, it was observed that gene expression in Appressoria seems to be influenced by host-derived signals, suggesting that transcriptomic analyses performed from in planta differentiated Appressoria would be potentially more informative than those from in vitro differentiated Appressoria. Nevertheless analysing Appressorial RNA obtained from in planta samples is often hampered by an excessive dilution of fungal RNA within plant RNA, besides uncertainty regarding the fungal or plant origin of RNA from highly conserved genes. To circumvent these difficulties, we have recovered Hemileia vastatrix Appressoria from Arabica coffee leaf surface using a film of nitrocellulose dissolved in butyl and ethyl acetates (nail polish), and extracted fungal RNA from the polish peel. RNA thus obtained is of good quality and usable for cDNA synthesis and transcriptomic (quantitative PCR) studies. This method could provide the means to investigate specific host-induced Appressoria-related fungal pathogenicity factors.
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Overview of the functional virulent genome of the coffee leaf rust pathogen Hemileia vastatrix with an emphasis on early stages of infection
Frontiers in Plant Science, 2014Co-Authors: Pedro Talhinhas, Helena Gil Azinheira, Andreia Loureiro, Bruno Vieira, Silvia Tavares, Dora Batista, Emmanuelle Morin, Anne-sophie Petitot, Octavio S. Paulo, Julie PoulainAbstract:Hemileia vastatrix is the causal agent of coffee leaf rust, the most important disease of coffee Arabica. In this work, a 454-pyrosequencing transcriptome analysis of H. vastatrix germinating urediniospores (gU) and Appressoria (Ap) was performed and compared to previously published in planta haustoria-rich (H) data. A total of 9234 transcripts were identified and annotated. Ca. 50% of these transcripts showed no significant homology to international databases. Only 784 sequences were shared by the three conditions, and 75% were exclusive of either gU (2146), Ap (1479) or H (3270). Relative transcript abundance and RT-qPCR analyses for a selection of genes indicated a particularly active metabolism, translational activity and production of new structures in the Appressoria and intense signaling, transport, secretory activity and cellular multiplication in the germinating urediniospores, suggesting the onset of a plant-fungus dialogue as early as at the germ tube stage. Gene expression related to the production of carbohydrate-active enzymes and accumulation of glycerol in germinating urediniospores and Appressoria suggests that combined lytic and physical mechanisms are involved in Appressoria-mediated penetration. Besides contributing to the characterization of molecular processes leading to Appressoria-mediated infection by rust fungi, these results point toward the identification of new H. vastatrix candidate virulence factors, with 516 genes predicted to encode secreted proteins.
Nicholas P Money - One of the best experts on this subject based on the ideXlab platform.
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confirmation of a link between fungal pigmentation turgor pressure and pathogenicity using a new method of turgor measurement
Fungal Genetics and Biology, 1996Co-Authors: Nicholas P Money, Richard J. HowardAbstract:Money, N. P., and Howard, R. J. 1996. Confirmation of a link between fungal pigmentation, turgor pressure, and pathogenicity using a new method of turgor measurement.Fungal Genetics and Biology20,217–227. A novel approach to turgor measurement has confirmed a link between melanin synthesis and Appressorial turgor pressure in the rice blast fungusMagnaporthe grisea.The new technique employs a cold stage to measure the melting point of ice within individual cells. Turgor is then calculated from the difference between the melting points of intracellular ice and ice in the fluid surrounding the cell. Conidia ofM. griseawere incubated on various surfaces, and Appressoria developed within 6 h. Measurements from conidia showed that wild-type and melanin-deficient strains generated the same pressures, which decreased before germ tube emergence. By contrast, wild-type Appressoria generated much higher pressures than Appressoria of a melanin-deficient buf−mutant. These experiments strengthen the hypothesis that melanin confers pathogenicity by facilitating the development of high pressures within Appressoria.
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Penetration of hard substrates by a fungus employing enormous turgor pressures.
Proceedings of the National Academy of Sciences of the United States of America, 1991Co-Authors: Richard J. Howard, Margaret A. Ferrari, David H. Roach, Nicholas P MoneyAbstract:Abstract Many fungal pathogens penetrate plant leaves from a specialized cell called an appressorium. The rice blast pathogen Magnaporthe grisea can also penetrate synthetic surfaces such as poly(vinyl chloride). Previous experiments have suggested that penetration requires an elevated Appressorial turgor pressure. In the present report we have used nonbiodegradable Mylar membranes, exhibiting a range of surface hardness, to test the proposition that penetration is driven by turgor. Reducing Appressorial turgor by osmotic stress inhibited penetration of these membranes. The size of the turgor deficit required to inhibit penetration was a function of the surface hardness. Penetration of the hardest membranes was inhibited by small decreases in Appressorial turgor, while penetration of the softer membranes was sensitive only to large decreases in turgor. Similarly, penetration of the host surface was inhibited in a manner comparable to penetration of the hardest Mylar membranes. Indirect measurements of turgor, obtained through osmotically induced collapse of Appressoria, indicated that the infection apparatus can generate turgor pressures in excess of 8.0 MPa (80 bars). We conclude that penetration of synthetic membranes, and host epidermal cells, is accomplished by application of the physical force derived from Appressorial turgor.
Philip M Dixon - One of the best experts on this subject based on the ideXlab platform.
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influence of temperature and wetness duration on conidia and Appressoria of colletotrichum acutatum on symptomless strawberry leaves
Phytopathology, 2003Co-Authors: Leonor F S Leandro, Mark L Gleason, Forrest W Nutter, Stephen N Wegulo, Philip M DixonAbstract:ABSTRACT Strawberry leaves (cv. Tristar) inoculated with Colletotrichum acuta-tum conidia were incubated at 10, 15, 20, 25, 30, and 35°C under continuous wetness, and at 25°C under six intermittent wetness regimes. The number of conidia and Appressoria was quantified on excised leaf disks. In order to assess pathogen survival, inoculated leaves were frozen and incubated to induce acervular development. Germination, secondary3 conidiation, and Appressorial development were significantly (P ≤ 0.05) affected by temperature and wetness treatments. Under continuous wetness, the optimum temperature range for conidial germination was 23.0 to 27.7°C, whereas the optimum temperature for Appressorial development ranged from 17.6 to 26.5°C. Secondary conidiation showed an optimum temperature range of 21.3 to 32.7°C and was most abundant between 12 and 36 h after inoculation. Conidial germination, Appressorial production, and secondary conidiation were favored by increasing wetness duration and more than 4 h of wetne...