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1.
PLoS Pathog ; 20(1): e1011988, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38289966

RESUMO

Autophagy and Cell wall integrity (CWI) signaling are critical stress-responsive processes during fungal infection of host plants. In the rice blast fungus Magnaporthe oryzae, autophagy-related (ATG) proteins phosphorylate CWI kinases to regulate virulence; however, how autophagy interplays with CWI signaling to coordinate such regulation remains unknown. Here, we have identified the phosphorylation of ATG protein MoAtg4 as an important process in the coordination between autophagy and CWI in M. oryzae. The ATG kinase MoAtg1 phosphorylates MoAtg4 to inhibit the deconjugation and recycling of the key ATG protein MoAtg8. At the same time, MoMkk1, a core kinase of CWI, also phosphorylates MoAtg4 to attenuate the C-terminal cleavage of MoAtg8. Significantly, these two phosphorylation events maintain proper autophagy levels to coordinate the development and pathogenicity of the rice blast fungus.


Assuntos
Ascomicetos , Magnaporthe , Oryza , Fosforilação , Virulência , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Magnaporthe/metabolismo , Autofagia , Parede Celular/metabolismo , Oryza/microbiologia , Doenças das Plantas/microbiologia , Regulação Fúngica da Expressão Gênica
2.
PLoS Pathog ; 17(6): e1009657, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34133468

RESUMO

GTP-binding protein (G-protein) and regulator of G-protein signaling (RGS) mediated signal transduction are critical in the growth and virulence of the rice blast pathogen Magnaporthe oryzae. We have previously reported that there are eight RGS and RGS-like proteins named MoRgs1 to MoRgs8 playing distinct and shared regulatory functions in M. oryzae and that MoRgs1 has a more prominent role compared to others in the fungus. To further explore the unique regulatory mechanism of MoRgs1, we screened a M. oryzae cDNA library for genes encoding MoRgs1-interacting proteins and identified MoCkb2, one of the two regulatory subunits of the casein kinase (CK) 2 MoCk2. We found that MoCkb2 and the sole catalytic subunit MoCka1 are required for the phosphorylation of MoRgs1 at the plasma membrane (PM) and late endosome (LE). We further found that an endoplasmic reticulum (ER) membrane protein complex (EMC) subunit, MoEmc2, modulates the phosphorylation of MoRgs1 by MoCk2. Interestingly, this phosphorylation is also essential for the GTPase-activating protein (GAP) function of MoRgs1. The balance among MoRgs1, MoCk2, and MoEmc2 ensures normal operation of the G-protein MoMagA-cAMP signaling required for appressorium formation and pathogenicity of the fungus. This has been the first report that an EMC subunit is directly linked to G-protein signaling through modulation of an RGS-casein kinase interaction.


Assuntos
Ascomicetos/metabolismo , Ascomicetos/patogenicidade , Proteínas Fúngicas/metabolismo , Interações Hospedeiro-Parasita/fisiologia , Virulência/fisiologia , Caseína Quinases/metabolismo , Fosforilação , Transdução de Sinais/fisiologia
3.
New Phytol ; 235(3): 1163-1178, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35451078

RESUMO

Magnaporthe oryzae secretes several effectors that modulate and hijack rice processes to colonize host cells, but the underlying mechanisms remain unclear. We report on a novel cytoplasmic effector MoIug4 that targets the rice ethylene pathway as a transcription repressor to subvert host immunity. We found that MoIug4 binds to the promoter of the host OsEIN2 gene that encodes a central signal transducer in the ethylene-signaling pathway. We also identified a MoIug4 interacting protein, OsAHL1, which acts as an AT-hook motif-containing protein binding to the A/T-rich promoter regions. Our knockout and overexpression studies showed that OsAHL1 positively regulates plant immunity in response to M. oryzae infection. OsAHL1 exhibits transcriptional regulatory activities by binding the OsEIN2 promoter region, similar to MoIug4. Intriguingly, we found that MoIug4 exhibits a higher binding affinity than OsAHL1 to the OsEIN2 promoter, suggesting differential regulatory specificities. These results revealed a counter-defense strategy by which the pathogen effector suppresses the activation of host defense genes by interfering with host transcription activator functions.


Assuntos
Magnaporthe , Oryza , Etilenos/metabolismo , Interações Hospedeiro-Patógeno/genética , Magnaporthe/genética , Oryza/metabolismo , Doenças das Plantas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica
4.
Proc Natl Acad Sci U S A ; 116(35): 17572-17577, 2019 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-31405986

RESUMO

Environmental conditions are key factors in the progression of plant disease epidemics. Light affects the outbreak of plant diseases, but the underlying molecular mechanisms are not well understood. Here, we report that the light-harvesting complex II protein, LHCB5, from rice is subject to light-induced phosphorylation during infection by the rice blast fungus Magnaporthe oryzae We demonstrate that single-nucleotide polymorphisms (SNPs) in the LHCB5 promoter control the expression of LHCB5, which in turn correlates with the phosphorylation of LHCB5. LHCB5 phosphorylation enhances broad-spectrum resistance of rice to M. oryzae through the accumulation of reactive oxidative species (ROS) in the chloroplast. We also show that LHCB5 phosphorylation-induced resistance is inheritable. Our results uncover an immunity mechanism mediated by phosphorylation of light-harvesting complex II.


Assuntos
Resistência à Doença/genética , Oryza/fisiologia , Fotossíntese/genética , Complexo de Proteína do Fotossistema II/genética , Doenças das Plantas/genética , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Luz , Oryza/microbiologia , Fosforilação , Complexo de Proteína do Fotossistema II/metabolismo , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas
5.
Pharm Biol ; 60(1): 255-273, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35148221

RESUMO

CONTEXT: Xinbao pill (XBW), a traditional Chinese herbal formula, is widely used in clinical treatment for cardiovascular diseases; however, the therapeutic effect of XBW on myocardial ischaemia-reperfusion injury (MI/RI) is unclear. OBJECTIVE: This study evaluates the cardioprotective effect and molecular mechanism of XBW against MI/RI. MATERIALS AND METHODS: A phytochemistry-based network pharmacology analysis was used to uncover the mechanism of XBW against MI/RI. Ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was used to identify chemicals. MI/RI-related targets of XBW were predicted using TargetNet database, OMIC database, etc. Sprague-Dawley (SD) rats under anterior descending artery ligation model were divided into Sham, MI/RI and XBW (180 mg/kg, intragastric administration). After 30 min ischaemia and 24 h reperfusion, heart tissues were collected for measurement of myocardial infarct size. After oxygen glucose deprivation for 6 h, H9c2 cells were treated with XBW (60, 240 and 720 µg/mL) and diazoxide (100 µM) for 18 h of reperfusion. RESULTS: Thirty-seven chemicals were identified in XBW; 50 MI/RI-related targets of XBW were predicted using indicated databases. XBW significantly reduced infarct size and creatine kinase MB (CK-MB) level after MI/RI; XBW protected H9c2 cells against OGD/R injury. Gene ontology (GO) and KEGG pathway enrichment analyses by String database showed that the cardioprotective effect of XBW was associated with autophagy and apoptosis signalling pathways. Experimental investigation also verified that XBW suppressed apoptosis, autophagy and endoplasmic reticulum (ER) stress. CONCLUSIONS: XBW showed therapeutic effects against MI/RI mainly via attenuating apoptosis though suppressing excessive autophagy and ER stress.


Assuntos
Cardiotônicos/farmacologia , Medicamentos de Ervas Chinesas/farmacologia , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Animais , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Cardiotônicos/administração & dosagem , Linhagem Celular , Relação Dose-Resposta a Droga , Medicamentos de Ervas Chinesas/administração & dosagem , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Masculino , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Farmacologia em Rede , Ratos , Ratos Sprague-Dawley
6.
PLoS Pathog ; 15(2): e1007382, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30802274

RESUMO

Regulator of G-protein signaling (RGS) proteins primarily function as GTPase-accelerating proteins (GAPs) to promote GTP hydrolysis of Gα subunits, thereby regulating G-protein mediated signal transduction. RGS proteins could also contain additional domains such as GoLoco to inhibit GDP dissociation. The rice blast fungus Magnaporthe oryzae encodes eight RGS and RGS-like proteins (MoRgs1 to MoRgs8) that have shared and distinct functions in growth, appressorium formation and pathogenicity. Interestingly, MoRgs7 and MoRgs8 contain a C-terminal seven-transmembrane domain (7-TM) motif typical of G-protein coupled receptor (GPCR) proteins, in addition to the conserved RGS domain. We found that MoRgs7, but not MoRgs8, couples with Gα MoMagA to undergo endocytic transport from the plasma membrane to the endosome upon sensing of surface hydrophobicity. We also found that MoRgs7 can interact with hydrophobic surfaces via a hydrophobic interaction, leading to the perception of environmental hydrophobiccues. Moreover, we found that MoRgs7-MoMagA endocytosis is regulated by actin patch-associated protein MoCrn1, linking it to cAMP signaling. Our studies provided evidence suggesting that MoRgs7 could also function in a GPCR-like manner to sense environmental signals and it, together with additional proteins of diverse functions, promotes cAMP signaling required for developmental processes underlying appressorium function and pathogenicity.


Assuntos
Magnaporthe/metabolismo , Proteínas dos Microfilamentos/metabolismo , Oryza/microbiologia , Proteínas RGS/metabolismo , AMP Cíclico/metabolismo , Endocitose , Proteínas Fúngicas/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Doenças das Plantas/microbiologia , Domínios Proteicos , Transdução de Sinais
7.
New Phytol ; 230(2): 720-736, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33423301

RESUMO

Plant pathogens exploit the extracellular matrix (ECM) to inhibit host immunity during their interactions with the host. The formation of ECM involves a series of continuous steps of vesicular transport events. To understand how such vesicle trafficking impacts ECM and virulence in the rice blast fungus Magnaporthe oryzae, we characterised MoSwa2, a previously identified actin-regulating kinase MoArk1 interacting protein, as an orthologue of the auxilin-like clathrin uncoating factor Swa2 of the budding yeast Saccharomyces cerevisiae. We found that MoSwa2 functions as an uncoating factor of the coat protein complex II (COPII) via an interaction with the COPII subunit MoSec24-2. Loss of MoSwa2 led to a deficiency in the secretion of extracellular proteins, resulting in both restricted growth of invasive hyphae and reduced inhibition of host immunity. Additionally, extracellular fluid (ECF) proteome analysis revealed that MoSwa2-regulated extracellular proteins include many redox proteins such as the berberine bridge enzyme-like (BBE-like) protein MoSef1. We further found that MoSef1 functions as an apoplastic virulent factor that inhibits the host immune response. Our studies revealed a novel function of a COPII uncoating factor in vesicular transport that is critical in the suppression of host immunity and pathogenicity of M. oryzae.


Assuntos
Magnaporthe , Oryza , Ascomicetos , Auxilinas , Clatrina , Proteínas Fúngicas , Doenças das Plantas , Virulência
8.
Nat Plants ; 10(4): 618-632, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38409290

RESUMO

Effector proteins secreted by plant pathogenic fungi are important artilleries against host immunity, but there is no precedent of such effectors being explored as antifungal targets. Here we demonstrate that MoErs1, a species-specific effector protein secreted by the rice blast fungus Magnaporthe oryzae, inhibits the function of rice papain-like cysteine protease OsRD21 involved in rice immunity. Disrupting MoErs1-OsRD21 interaction effectively controls rice blast. In addition, we show that FY21001, a structure-function-based designer compound, specifically binds to and inhibits MoErs1 function. FY21001 significantly and effectively controls rice blast in field tests. Our study revealed a novel concept of targeting pathogen-specific effector proteins to prevent and manage crop diseases.


Assuntos
Proteínas Fúngicas , Oryza , Doenças das Plantas , Oryza/microbiologia , Doenças das Plantas/microbiologia , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Interações Hospedeiro-Patógeno , Papaína/metabolismo , Ascomicetos , Magnaporthe
9.
ISME J ; 17(7): 1089-1103, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37156836

RESUMO

As social micropredators, myxobacteria are studied for their abilities to prey on bacteria and fungi. However, their predation of oomycetes has received little attention. Here, we show that Archangium sp. AC19 secretes a carbohydrate-active enzyme (CAZyme) cocktail during predation on oomycetes Phytophthora. These enzymes include three specialized ß-1,3-glucanases (AcGlu13.1, -13.2 and -13.3) that act as a cooperative consortium to target ß-1,3-glucans of Phytophthora. However, the CAZymes showed no hydrolytic effects on fungal cells, even though fungi contain ß-1,3-glucans. Heterologous expression of AcGlu13.1, -13.2 or -13.3 enzymes in Myxococcus xanthus DK1622, a model myxobacterium that antagonizes but does not predate on P. sojae, conferred a cooperative and mycophagous ability that stably maintains myxobacteria populations as a mixture of engineered strains. Comparative genomic analyses suggest that these CAZymes arose from adaptive evolution among Cystobacteriaceae myxobacteria for a specific prey killing behavior, whereby the presence of Phytophthora promotes growth of myxobacterial taxa by nutrient release and consumption. Our findings demonstrate that this lethal combination of CAZymes transforms a non-predatory myxobacterium into a predator with the ability to feed on Phytophthora, and provides new insights for understanding predator-prey interactions. In summary, our work extends the repertoire of myxobacteria predatory strategies and their evolution, and suggests that these CAZymes can be engineered as a functional consortium into strains for biocontrol of Phytophothora diseases and hence crop protection.


Assuntos
Myxococcales , Myxococcus xanthus , Phytophthora , Animais , Myxococcales/genética , Comportamento Predatório , Myxococcus xanthus/genética , Glucanos , Phytophthora/genética
10.
Mol Plant ; 15(8): 1347-1366, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35799449

RESUMO

Apoplastic ascorbate oxidases (AOs) play a critical role in reactive oxygen species (ROS)-mediated innate host immunity by regulating the apoplast redox state. To date, little is known about how apoplastic effectors of the rice blast fungus Magnaporthe oryzae modulate the apoplast redox state of rice to subvert plant immunity. In this study, we demonstrated that M. oryzae MoAo1 is an AO that plays a role in virulence by modulating the apoplast redox status of rice cells. We showed that MoAo1 inhibits the activity of rice OsAO3 and OsAO4, which also regulate the apoplast redox status and plant immunity. In addition, we found that MoAo1, OsAO3, and OsAO4 all exhibit polymorphic variations whose varied interactions orchestrate pathogen virulence and rice immunity. Taken together, our results reveal a critical role for extracellular redox enzymes during rice blast infection and shed light on the importance of the apoplast redox state and its regulation in plant-pathogen interactions.


Assuntos
Magnaporthe , Oryza , Ascomicetos , Ascorbato Oxidase , Interações Hospedeiro-Patógeno , Magnaporthe/fisiologia , Oryza/microbiologia , Oxirredução , Doenças das Plantas/microbiologia , Imunidade Vegetal
11.
mBio ; 11(2)2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32209696

RESUMO

The appressoria that are generated by the rice blast fungus Magnaporthe oryzae in response to surface cues are important for successful colonization. Previous work showed that regulators of G-protein signaling (RGS) and RGS-like proteins play critical roles in appressorium formation. However, the mechanisms by which these proteins orchestrate surface recognition for appressorium induction remain unclear. Here, we performed comparative transcriptomic studies of ΔMorgs mutant and wild-type strains and found that M. oryzae Aa91 (MoAa91), a homolog of the auxiliary activity family 9 protein (Aa9), was required for surface recognition of M. oryzae We found that MoAA91 was regulated by the MoMsn2 transcription factor and that its disruption resulted in defects in both appressorium formation on the artificial inductive surface and full virulence of the pathogen. We further showed that MoAa91 was secreted into the apoplast space and was capable of competing with the immune receptor chitin elicitor-binding protein precursor (CEBiP) for chitin binding, thereby suppressing chitin-induced plant immune responses. In summary, we have found that MoAa91 is a novel signaling molecule regulated by RGS and RGS-like proteins and that MoAa91 not only governs appressorium development and virulence but also functions as an effector to suppress host immunity.IMPORTANCE The rice blast fungus Magnaporthe oryzae generates infection structure appressoria in response to surface cues largely due to functions of signaling molecules, including G-proteins, regulators of G-protein signaling (RGS), mitogen-activated protein (MAP) kinase pathways, cAMP signaling, and TOR signaling pathways. M. oryzae encodes eight RGS and RGS-like proteins (MoRgs1 to MoRgs8), and MoRgs1, MoRgs3, MoRgs4, and MoRgs7 were found to be particularly important in appressorium development. To explore the mechanisms by which these proteins regulate appressorium development, we have performed a comparative in planta transcriptomic study and identified an auxiliary activity family 9 protein (Aa9) homolog that we named MoAa91. We showed that MoAa91 was secreted from appressoria and that the recombinant MoAa91 could compete with a chitin elicitor-binding protein precursor (CEBiP) for chitin binding, thereby suppressing chitin-induced plant immunity. By identifying MoAa91 as a novel signaling molecule functioning in appressorium development and an effector in suppressing host immunity, our studies revealed a novel mechanism by which RGS and RGS-like proteins regulate pathogen-host interactions.


Assuntos
Ascomicetos/patogenicidade , Quitina/metabolismo , Proteínas Fúngicas/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Oryza/imunologia , Imunidade Vegetal , Ascomicetos/genética , Proteínas Fúngicas/genética , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Oryza/microbiologia , Doenças das Plantas/microbiologia , Transdução de Sinais , Virulência
12.
Sci Rep ; 6: 24911, 2016 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-27113712

RESUMO

Electron-transferring flavoprotein (ETF) and its dehydrogenase (ETFDH) are highly conserved electron carriers which mainly function in mitochondrial fatty acid ß oxidation. Here, we report the identification and characterization of ETF α and ß subunit encoding genes (ETFA and ETFB) and ETFDH encoding gene (ETFDH) in the rice blast fungus Magnaporthe oryzae. It was demonstrated that, by impacting fatty acid metabolism, ETF and ETFDH mutations led to severe growth and conidiation defects, which could be largely rescued by exogenous acetate or carbonate. Furthermore, although conidium germination and appressorium formation appeared to be normal in ETF and ETFDH mutants, most appressoria failed to penetrate the host epidermis due to low turgor pressure. The few appressoria that succeeded in penetration were severely restricted in invasive growth and consequently failed to cause disease. Moreover, ETF mutant etfb(-) induced ROS accumulation in infected host cells and exogenous antioxidant GSH accelerated mutant invading growth without increasing the penetration rate. In addition, mutant etfb(-) displayed elevated lipid body accumulation and reduced ATP synthesis. Taken together, ETF and ETFDH play an important role in fungal development and plant infection in M. oryzae by regulation of fatty acid metabolism, turgor establishment and induction of host ROS accumulation.


Assuntos
Flavoproteínas Transferidoras de Elétrons/genética , Proteínas Fúngicas/genética , Proteínas Ferro-Enxofre/genética , Magnaporthe/fisiologia , Oryza/microbiologia , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Doenças das Plantas/microbiologia , Flavoproteínas Transferidoras de Elétrons/metabolismo , Ácidos Graxos/metabolismo , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Proteínas Ferro-Enxofre/metabolismo , Magnaporthe/patogenicidade , Mutação , Oxirredução , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Esporos Fúngicos/fisiologia
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