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1.
Plant Sci ; : 112244, 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39244093

RESUMEN

Co-infection, caused by multiple pathogen attacks on an organism, can lead to disease development or immunity. This complex interaction can be synergetic, co-existing, or antagonistic, ultimately influencing disease severity. The interaction between fungus, bacterium, and virus (three kingdom pathogens) is most prevalent. However, the underlying mechanisms of co-infection need to be explored further. In this study, we investigated the co-infection phenomenon in rice plants exposed to multiple pathogen species, specifically Rice necrosis mosaic virus (RNMV) and rice blast fungus (Magnaporthe oryzae, MO), bacterial leaf blight (Xanthomonas oryzae pv. oryzae, XO) or Cucumber mosaic virus (CMV). Our research showed that RNMV interacts synergistically with MO, XO, or CMV, increasing pathogen growth and lesion size. These findings suggest positive synergy in RNMV co-infections with three kingdom pathogens, increasing accumulation and symptoms. Additionally, to investigate the role of RNAi in pathogen synergism, we analyzed rice mutant lines deficient in RNA-dependent RNA polymerase 1 (OsRDR1) or 6 (OsRDR6). Notably, we observed the loss of synergy in each mutant line, highlighting the crucial role of OsRDR1 and OsRDR6 in maintaining the positive interaction between RNMV and three kingdom pathogens. Hence, our study emphasized the role of the RNA silencing pathway in the intricate landscape of pathogen interactions; the study's outcome could be applied to understand the plant defense response to improve crop yields.

2.
Heliyon ; 10(16): e36141, 2024 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-39224266

RESUMEN

Rice blast disease, caused by Magnaporthe oryzae, poses a significant threat to global rice production, necessitating the development of effective and sustainable management strategies. Biological control using beneficial microbes like Bacillus amyloliquefaciens has emerged as a promising approach due to its ability to enhance plant resistance and reduce disease incidence. Nano-encapsulation of bacteria, which involves embedding beneficial microbes within nanomaterials, offers a novel method to improve the stability, survival, and efficacy of these biocontrol agents. This study evaluated the capacity of encapsulated Bacillus amyloliquefaciens D203, embedded within an alginate-bentonite coating infused with titanium nanoparticles (TNs), to stimulate defense responses in rice seedlings challenged by the Magnaporthe oryzae the causal agent of rice blast disease. Encapsulation was achieved using the extrusion technique, with some modifications. Using a completely randomized design, the experiment was conducted in a greenhouse, with four treatments replicated four times. The experiment used the popular Kenyan rice variety "BASMATI 370". The study investigated the impact of strain D203 on the incidence, severity, and area under disease progress curves related to M. oryzae, as well as the expression of defense-related enzymes. The results demonstrated that rice plants derived from seeds coated with the D203 encapsulated B. amyloliquefaciens strain exhibited higher levels of defense-related enzyme expression, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), superoxide dismutase (SOD) and catalase (CAT), compared to controls. In addition, the incidence and severity of the disease were markedly lower in plants treated with encapsulated B. amyloliquefaciens compared to controls, sometimes paralleling the efficacy of hexaconazole treatment. These findings suggest that the encapsulation of strain D203 has the potential to enhance resistance against rice blast disease by inducing systemic resistance through the production of antioxidant enzymes.

3.
Virulence ; 15(1): 2403566, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-39285518

RESUMEN

The filamentous fungus Magnaporthe oryzae is widely recognized as a notorious plant pathogen responsible for causing rice blasts. With rapid advancements in molecular biology technologies, numerous regulatory mechanisms have been thoroughly investigated. However, most recent studies have predominantly focused on infection-related pathways or host defence mechanisms, which may be insufficient for developing novel structure-based prevention strategies. A substantial body of literature has utilized cryo-electron microscopy and X-ray diffraction to explore the relationships between functional components, shedding light on the identification of potential drug targets. Owing to the complexity of protein extraction and stochastic nature of crystallization, obtaining high-quality structures remains a significant challenge for the scientific community. Emerging computational tools such as AlphaFold for structural prediction, docking for interaction analysis, and molecular dynamics simulations to replicate in vivo conditions provide novel avenues for overcoming these challenges. In this review, we aim to consolidate the structural biological advancements in M. oryzae, drawing upon mature experimental experiences from other species such as Saccharomyces cerevisiae and mammals. We aim to explore the potential of protein construction to address the invasion and proliferation of M. oryzae, with the goal of identifying new drug targets and designing small-molecule compounds to manage this disease.


Asunto(s)
Proteínas Fúngicas , Oryza , Enfermedades de las Plantas , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ascomicetos/genética , Ascomicetos/patogenicidad , Ascomicetos/química , Microscopía por Crioelectrón
4.
J Microbiol Methods ; 224: 107012, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39106934

RESUMEN

A method for separating M. oryzae from rice samples infected with multiple pathogens using basic laboratory equipment is described. We conducted a series of experiments to obtain a single spore of M. oryzae. This method can also be used to isolate spores from other fungal species.


Asunto(s)
Oryza , Enfermedades de las Plantas , Esporas Fúngicas , Oryza/microbiología , Esporas Fúngicas/aislamiento & purificación , Enfermedades de las Plantas/microbiología , Técnicas Microbiológicas/métodos , Ascomicetos
5.
Phytopathology ; 114(8): 1917-1925, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39135297

RESUMEN

The rice blast fungus Magnaporthe oryzae poses a significant challenge to maintaining rice production. Developing rice varieties with resistance to this disease is crucial for its effective control. To understand the genetic variability of blast isolates collected between 2015 and 2017, the 27 monogenic rice lines that carry specific resistance genes were used to evaluate blast disease reactions. Based on criteria such as viability, virulence, and reactions to resistance genes, 20 blast isolates were selected as representative strains. To identify novel resistance genes, a quantitative trait locus analysis was carried out utilizing a mixture of the 20 representative rice blast isolates and a rice population derived from crossing the blast-resistant cultivar 'Cheongcheong' with the blast-susceptible cultivar 'Nagdong'. This analysis revealed a significant locus, RM1227-RM1261 on chromosome 12, that is associated with rice blast resistance. Within this locus, 12 disease resistance-associated protein genes were identified. Among them, OsDRq12, a member of the nucleotide-binding, leucine-rich repeat disease resistance family, was chosen as the target gene for additional computational investigation. The findings of this study have significant implications for enhancing rice production and ensuring food security by controlling rice blast and developing resistant rice cultivars.


Asunto(s)
Resistencia a la Enfermedad , Variación Genética , Oryza , Enfermedades de las Plantas , Oryza/microbiología , Oryza/inmunología , Oryza/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Resistencia a la Enfermedad/genética , Sitios de Carácter Cuantitativo/genética , Genes de Plantas/genética , Ascomicetos/genética , Ascomicetos/patogenicidad , Ascomicetos/fisiología , Proteínas de Plantas/genética , Magnaporthe/genética , Magnaporthe/patogenicidad , Magnaporthe/fisiología
6.
Appl Microbiol Biotechnol ; 108(1): 437, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-39133429

RESUMEN

ß-1,6-Glucan plays a crucial role in fungal cell walls by linking the outer layer of mannoproteins and the inner layer of ß-1,3-glucan, contributing significantly to the maintenance of cell wall rigidity. Therefore, the hydrolysis of ß-1,6-glucan by ß-1,6-glucanase directly leads to the disintegration of the fungal cell wall. Here, a novel ß-1,6-glucanase FlGlu30 was identified from the endophytic Flavobacterium sp. NAU1659 and heterologously expressed in Escherichia coli BL21 (DE3). The optimal reaction conditions of purified FlGlu30 were 50℃ and pH 6.0, resulting in a specific activity of 173.1 U/mg using pustulan as the substrate. The hydrolyzed products of FlGlu30 to pustulan were mainly gentianose within 1 h of reaction. With the extension of reaction time, gentianose was gradually hydrolyzed to glucose, indicating that FlGlu30 is an endo-ß-1,6-glucanase. The germination of Magnaporthe oryzae Guy11 spores could not be inhibited by FlGlu30, but the appressorium formation of spores was completely inhibited under the concentration of 250.0 U/mL FlGlu30. The disruptions of cell wall and accumulation of intracellular reactive oxide species (ROS) were observed in FlGlu30-treated M. oryzae Guy11 cells, suggesting the significant importance of ß-1,6-glucan as a potential antifungal target and the potential application of FlGlu30. KEY POINTS: • ß-1,6-Glucan is a key component maintaining the rigid structure of fungal cell wall. • ß-1,6-Glucanase is an antifungal protein with significant potential applications. • FlGlu30 is the first reported ß-1, 6-glucanase derived from Flavobacterium.


Asunto(s)
Antifúngicos , Pared Celular , Escherichia coli , Flavobacterium , Glicósido Hidrolasas , Flavobacterium/enzimología , Flavobacterium/genética , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Hidrólisis , Antifúngicos/farmacología , Antifúngicos/metabolismo , Pared Celular/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Glucanos/metabolismo , Concentración de Iones de Hidrógeno , beta-Glucanos/metabolismo , Clonación Molecular , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura , Especificidad por Sustrato , Polisacáridos
7.
Dev Cell ; 2024 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-39191251

RESUMEN

Ergosterols are essential components of fungal plasma membranes. Inhibitors targeting ergosterol biosynthesis (ERG) genes are critical for controlling fungal pathogens, including Magnaporthe oryzae, the fungus that causes rice blast. However, the translational mechanisms governing ERG gene expression remain largely unexplored. Here, we show that the Trm6/Trm61 complex catalyzes dynamic N1-methyladenosine at position 58 (m1A58) in 51 transfer RNAs (tRNAs) of M. oryzae, significantly influencing translation at both the initiation and elongation stages. Notably, tRNA m1A58 promotes elongation speed at most cognate codons mainly by enhancing eEF1-tRNA binding rather than affecting tRNA abundance or charging. The absence of m1A58 leads to substantial decreases in the translation of ERG genes, ergosterol production, and, consequently, fungal virulence. Simultaneously targeting the Trm6/Trm61 complex and the ergosterol biosynthesis pathway markedly improves rice blast control. Our findings demonstrate an important role of m1A58-mediated translational regulation in ergosterol production and fungal infection, offering a potential strategy for fungicide development.

8.
Antioxidants (Basel) ; 13(8)2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39199257

RESUMEN

Mitogen-activated protein (MAP) kinase (MAPK) signaling pathway is important in plant immune responses, involved in iron- and reactive oxygen species (ROS)-dependent ferroptotic cell death mediated by Ca2+. High Ca2+ influx triggered iron-dependent ROS accumulation, lipid peroxidation, and subsequent hypersensitive response (HR) cell death in rice (Oryza sativa). Apoplastic Ca2+ chelation by EGTA during avirulent Magnaporthe oryzae infection altered Ca2+, ROS, and Fe2+ accumulation, increasing rice susceptibility to infection. By contrast, acibenzolar-S-methyl (ASM), a plant defense activator, significantly enhanced Ca2+ influx, and H2O2 accumulation, triggering rice ferroptotic cell death during virulent Magnaporthe oryzae infection. Here, we report a novel role of the MAPK signaling pathway in regulating cytoplasmic Ca2+ increase during ferroptotic cell death in rice immunity, using the ΔOsmek2 knockout mutant rice. The knockout of rice OsMEK2 impaired the ROS accumulation, lipid peroxidation, and iron accumulation during avirulent M. oryzae infection. This study has shown that OsMEK2 could positively regulate iron- and ROS-dependent ferroptotic cell death in rice by modulating the expression of OsNADP-ME, OsRBOHB, OsPLC, and OsCNGC. This modulation indicates a possible mechanism for how OsMEK2 participates in Ca2+ regulation in rice ferroptotic cell death, suggesting its broader role in plant immune responses in response to M. oryzae infection.

9.
Pest Manag Sci ; 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39180165

RESUMEN

BACKGROUND: Rice blast has a significant detrimental impact on rice yields, so developing efficient biological control technologies is an effective means for rice blast prevention and control. The GroEL protein has proven to be effective at preventing and managing the pathogenicity of rice blast. RESULTS: Here, we analyzed the amino acid sequence of the GroEL protein and synthesized the '60 kDa chaperonin signature' (350-373 amino acids) peptide SP1.2, which has potent antifungal activity. Notably, the SP1.2 peptide exhibited potent fungicidal activity against Magnaporthe oryzae, effectively inhibiting appressorium germination. Electron microscopy revealed that SP1.2 disrupted the fungal plasma membrane and bound to multiple bioactive phosphoinositides in vitro, triggering the production of reactive oxygen species. Furthermore, it also caused an increase in the acetylation of M. oryzae and induced autophagy in cells. The spray application of SP1.2 significantly reduced the number of disease spots caused by the fungal pathogen M. oryzae in rice, enhancing the defense response of rice plants. Field trials showed that the control effect was 64.59% after spraying SP1.2. CONCLUSION: Our study illustrates the antifungal activity of the structurally unique SP1.2 peptide against plant fungal pathogens and paves the way for the future development of this class of peptides as antifungal agents. © 2024 Society of Chemical Industry.

10.
New Phytol ; 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39180241

RESUMEN

The retromer complex is a conserved sorting machinery that maintains cellular protein homeostasis by transporting vesicles containing cargo proteins to defined destinations. It is known to sort proteins at the vacuole membranes for retrograde trafficking, preventing their degradation in the vacuole. However, the detailed mechanism of retromer recruitment to the vacuole membrane has not yet been elucidated. Here, we show that the vacuolar SNARE complex MoPep12-MoVti1-MoVam7-MoYkt6 regulates retromer-mediated vesicle trafficking by recruiting the retromer to the vacuole membrane, which promotes host invasion in Magnaporthe oryzae. Such recruitment is also essential for the retrieval of the autophagy regulator MoAtg8 and enables appressorium-mediated host penetration. Furthermore, the vacuolar SNARE subunits are involved in suppressing the host defense response by regulating the deployment of retromer-MoSnc1-mediated effector secretion. Altogether, our results provide insights into the mechanism of vacuolar SNAREs-dependent retromer recruitment which is necessary for pathogenicity-related membrane trafficking events in the rice blast fungus.

11.
Mol Biol Rep ; 51(1): 935, 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39180629

RESUMEN

Rice blast is a major problem in agriculture, affecting rice production and threatening food security worldwide. This disease, caused by the fungus Magnaporthe oryzae, has led to a lot of research since the discovery of the first resistance gene, pib, in 1999. Researchers have now identified more than 50 resistance genes on eight of the twelve chromosomes in rice, each targeting different strains of the pathogen.These genes are spread out across seventeen different loci. These genes, which primarily code for nucleotide-binding and leucine-rich repeat proteins, play an important part in the defense of rice against the pathogen, either alone or in combination with other genes. An important characteristic of these genes is the allelic or paralogous interactions that exist within these loci. These relationships contribute to the gene's increased capacity for evolutionary adaptation. The ability of resistance proteins to recognize and react to novel effectors is improved by the frequent occurrence of variations within the domains that are responsible for recognizing pathogen effectors. The purpose of this review is to summarize the progress that has been made in identifying these essential genes and to investigate the possibility of utilizing the allelic variants obtained from these genes in future rice breeding efforts to increase resistance to rice blast.


Asunto(s)
Alelos , Resistencia a la Enfermedad , Oryza , Enfermedades de las Plantas , Oryza/genética , Oryza/microbiología , Oryza/inmunología , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Variación Genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fitomejoramiento/métodos , Magnaporthe/patogenicidad , Genes de Plantas , Ascomicetos/patogenicidad , Ascomicetos/genética
12.
J Appl Genet ; 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39180632

RESUMEN

Rice blast disease, caused by Magnaporthe oryzae, reigns as the top-most cereal killer, jeopardizing global food security. This necessitates the timely scouting of pathogen stress-responsive genes during the early infection stages. Thus, we integrated time-series microarray (GSE95394) and RNA-Seq (GSE131641) datasets to decipher rice transcriptome responses at 12- and 24-h post-infection (Hpi). Our analysis revealed 1580 differentially expressed genes (DEGs) overlapped between datasets. We constructed a protein-protein interaction (PPI) network for these DEGs and identified significant subnetworks using the MCODE plugin. Further analysis with CytoHubba highlighted eight plausible hub genes for pathogenesis: RPL8 (upregulated) and RPL27, OsPRPL3, RPL21, RPL9, RPS5, OsRPS9, and RPL17 (downregulated). We validated the expression levels of these hub genes in response to infection, finding that RPL8 exhibited significantly higher expression compared with other downregulated genes. Remarkably, RPL8 formed a distinct cluster in the co-expression network, whereas other hub genes were interconnected, with RPL9 playing a central role, indicating its pivotal role in coordinating gene expression during infection. Gene Ontology highlighted the enrichment of hub genes in the ribosome and protein translation processes. Prior studies suggested that plant immune defence activation diminishes the energy pool by suppressing ribosomes. Intriguingly, our study aligns with this phenomenon, as the identified ribosomal proteins (RPs) were suppressed, while RPL8 expression was activated. We anticipate that these RPs could be targeted to develop new stress-resistant rice varieties, beyond their housekeeping role. Overall, integrating transcriptomic data revealed more common DEGs, enhancing the reliability of our analysis and providing deeper insights into rice blast disease mechanisms.

13.
J Agric Food Chem ; 72(36): 19657-19666, 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39190007

RESUMEN

Magnaporthe oryzae, the causal agent of rice blast, is a fungal disease pathogen. Bacillus spp. have emerged as the most promising biological control agent alternative to chemical fungicides. In this study, the bacterial strain JLU-1 with significant antagonistic activity isolated from the rhizosphere soil of rice was identified as Bacillus velezensis through whole-genome sequencing, average nucleotide identity analysis, and 16S rRNA gene sequencing. Twelve gene clusters for secondary metabolite synthesis were identified in JLU-1. Furthermore, 3 secondary metabolites were identified in JLU-1, and the antagonistic effect of secondary metabolites against fungal pathogens was confirmed. Exposure to JLU-1 reduced the virulence of M. oryzae, and JLU-1 has the ability to induce the reactive oxygen species production of rice and improve the salt tolerance of rice. All of these results indicated that JLU-1 and its secondary metabolites have the promising potential to be developed into a biocontrol agent to control fungal diseases.


Asunto(s)
Bacillus , Agentes de Control Biológico , Oryza , Enfermedades de las Plantas , Bacillus/genética , Bacillus/metabolismo , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Agentes de Control Biológico/farmacología , Agentes de Control Biológico/metabolismo , Metabolismo Secundario , Antibiosis , Microbiología del Suelo , Ascomicetos/genética , Ascomicetos/metabolismo , Control Biológico de Vectores , Magnaporthe/genética , Magnaporthe/metabolismo
14.
Plant Physiol Biochem ; 215: 109058, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39181086

RESUMEN

Nitrogen (N) is essential for the physiological processes of plants. However, the specific mechanisms by which different nitrogen forms influence rice blast pathogenesis remain poorly understood. This study used hydroponic assays to explore how ammonium (NH4+) and nitrate (NO3-) affect rice after inoculation with Magnaporthe oryzae (M. oryzae). The results showed that NH4+, compared to NO3-, significantly reduced disease severity, fungal growth, fungal hyphae number, the expansion capacity of infectious hyphae, and disease-related loss of photosynthesis. Additionally, NH4+ enhanced the expression of defense-related genes, including OsPBZ1, OsCHT1, OsPR1a, and OsPR10. NH4+-treated rice also exhibited higher hydrogen peroxide (H2O2) accumulation and increased antioxidant enzyme activities. Moreover, susceptibility to rice blast disease increased when H2O2 was scavenged, while a reduction in susceptibility was observed with the application of exogenous H2O2. These results suggest that ammonium enhances rice resistance to M. oryzae, potentially through H2O2 accumulation. The findings provide valuable insights into how different nitrogen forms affect plant immunity in rice, which is crucial for controlling rice blast and ensuring stable food production.


Asunto(s)
Compuestos de Amonio , Resistencia a la Enfermedad , Peróxido de Hidrógeno , Oryza , Enfermedades de las Plantas , Oryza/microbiología , Oryza/metabolismo , Oryza/genética , Oryza/inmunología , Peróxido de Hidrógeno/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Compuestos de Amonio/metabolismo , Compuestos de Amonio/farmacología , Resistencia a la Enfermedad/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Magnaporthe/fisiología , Ascomicetos/patogenicidad , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética
15.
New Phytol ; 243(6): 2332-2350, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39056291

RESUMEN

Protein posttranslational modifications play crucial roles in plant immunity through modulating a complicated signaling network mediated by different hormones. We previously demonstrated that OsATL32, an ATL-type E3 ligase, negatively contributes to rice immunity against Magnaporthe oryzae. Here, we show that OsATL32 forms a loop with OsPPKL2 and OsGSK2 through distinct protein posttranslational modifications to modulate rice immunity. OsATL32 ubiquitinates OsPPKL2, a protein phosphatase with Kelch-like repeat domains that exerts positive roles in regulating rice immunity against M. oryzae and chitin-triggered immune responses, for degradation. The glycogen synthase kinase 2 (OsGSK2), which acts as a negative regulator of rice immunity against M. oryzae and chitin-triggered immune responses, phosphorylates OsATL32 to elevate its protein stability and E3 ligase activity on OsPPKL2. Moreover, OsPPKL2 directly dephosphorylates OsGSK2, affecting its kinase activity on substrates including OsATL32 for phosphorylation. Like OsGSK2 as a BR signaling repressor, OsATL32 negatively regulates BR signaling; conversely, OsPPKL2 plays a positive role in BR signaling. These findings provide a molecular mechanism in which OsATL32 serves as a node connecting BR signaling and immunity by associating with OsPPKL2 and OsGSK2, assembling into a distinct protein posttranslational modifications-linked loop that functions in rice BR signaling and immunity.


Asunto(s)
Oryza , Enfermedades de las Plantas , Inmunidad de la Planta , Proteínas de Plantas , Procesamiento Proteico-Postraduccional , Oryza/genética , Oryza/inmunología , Oryza/microbiología , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Fosforilación , Ubiquitinación , Transducción de Señal , Magnaporthe/fisiología , Brasinoesteroides/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/genética , Regulación de la Expresión Génica de las Plantas , Quitina/metabolismo , Glucógeno Sintasa Quinasas/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Fosfoproteínas Fosfatasas/genética , Ascomicetos
16.
Microorganisms ; 12(7)2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-39065092

RESUMEN

Magnaporthe oryzae is one of the most important fungal pathogens of rice. Chitin and avirulent strains can induce two layers of immunity response, pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI), in rice with cognate R genes. However, little is known about the assembly of the rice microbiome induced by PTI and ETI in rice. In this study, we investigate the impact of continuous treatment of the avirulent M. oryzae strain with AvrPi9 and chitin on the bacterial endophytic community of rice varieties harboring resistant gene Pi9 and their antagonistic activity against rice blast fungus. Analysis of the 16S rRNA showed a significant increase in the diversity and microbial co-occurrence network complexity and the number of beneficial taxa-Bacillus, Pseudomonas, Microbacterium, and Stenotrophomonas spp.-following the chitin and avirulent strain treatments. The antifungal assay with bacterial endophytes recovered from the leaves showed few bacteria with antagonistic potential in rice treated with avirulent strains, suggesting that the sequential treatment of the avirulent strain decreased the antagonistic bacteria against M. oryzae. Moreover, we identified Bacillus safensis Ch_66 and Bacillus altitudinis Nc_68 with overall antagonistic activities in vivo and in vitro. Our findings provide a novel insight into rice microbiome assembly in response to different innate immunity reactions.

17.
Mol Plant Microbe Interact ; : MPMI12230212CR, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-38949402

RESUMEN

Effector secretion by different routes mediates the molecular interplay between host plant and pathogen, but mechanistic details in eukaryotes are sparse. This may limit the discovery of new effectors that could be utilized for improving host plant disease resistance. In fungi and oomycetes, apoplastic effectors are secreted via the conventional endoplasmic reticulum (ER)-Golgi pathway, while cytoplasmic effectors are packaged into vesicles that bypass Golgi in an unconventional protein secretion (UPS) pathway. In Magnaporthe oryzae, the Golgi bypass UPS pathway incorporates components of the exocyst complex and a t-SNARE, presumably to fuse Golgi bypass vesicles to the fungal plasma membrane. Upstream, cytoplasmic effector mRNA translation in M. oryzae requires the efficient decoding of AA-ending codons. This involves the modification of wobble uridines in the anticodon loop of cognate tRNAs and fine-tunes cytoplasmic effector translation and secretion rates to maintain biotrophic interfacial complex integrity and permit host infection. Thus, plant-fungal interface integrity is intimately tied to effector codon usage, which is a surprising constraint on pathogenicity. Here, we discuss these findings within the context of fungal and oomycete effector discovery, delivery, and function in host cells. We show how cracking the codon code for unconventional cytoplasmic effector secretion in M. oryzae has revealed AA-ending codon usage bias in cytoplasmic effector mRNAs across kingdoms, including within the RxLR-dEER motif-encoding sequence of a bona fide Phytophthora infestans cytoplasmic effector, suggesting its subjection to translational speed control. By focusing on recent developments in understanding unconventional effector secretion, we draw attention to this important but understudied area of host-pathogen interactions. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

18.
Cell Commun Signal ; 22(1): 362, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39010102

RESUMEN

Dihydroorotase (DHOase) is the third enzyme in the six enzymatic reaction steps of the endogenous pyrimidine nucleotide de novo biosynthesis pathway, which is a metabolic pathway conserved in both bacteria and eukaryotes. However, research on the biological function of DHOase in plant pathogenic fungi is very limited. In this study, we identified and named MoPyr4, a homologous protein of Saccharomyces cerevisiae DHOase Ura4, in the rice blast fungus Magnaporthe oryzae and investigated its ability to regulate fungal growth, pathogenicity, and autophagy. Deletion of MoPYR4 led to defects in growth, conidiation, appressorium formation, the transfer and degradation of glycogen and lipid droplets, appressorium turgor accumulation, and invasive hypha expansion in M. oryzae, which eventually resulted in weakened fungal pathogenicity. Long-term replenishment of exogenous uridine-5'-phosphate (UMP) can effectively restore the phenotype and virulence of the ΔMopyr4 mutant. Further study revealed that MoPyr4 also participated in the regulation of the Pmk1-MAPK signaling pathway, co-localized with peroxisomes for the oxidative stress response, and was involved in the regulation of the Osm1-MAPK signaling pathway in response to hyperosmotic stress. In addition, MoPyr4 interacted with MoAtg5, the core protein involved in autophagy, and positively regulated autophagic degradation. Taken together, our results suggested that MoPyr4 for UMP biosynthesis was crucial for the development and pathogenicity of M. oryzae. We also revealed that MoPyr4 played an essential role in the external stress response and pathogenic mechanism through participation in the Pmk1-MAPK signaling pathway, peroxisome-related oxidative stress response mechanism, the Osm1-MAPK signaling pathway and the autophagy pathway.


Asunto(s)
Autofagia , Proteínas Fúngicas , Oryza , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Oryza/microbiología , Virulencia/genética , Peroxisomas/metabolismo , Enfermedades de las Plantas/microbiología , Ascomicetos/patogenicidad , Ascomicetos/genética , Ascomicetos/enzimología , Sistema de Señalización de MAP Quinasas , Estrés Oxidativo
19.
Front Microbiol ; 15: 1429065, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39027104

RESUMEN

As an essential component of the fungal cell wall, ß-1,6-glucan has an important role in the growth and development of fungi, but its distribution has not been investigated in Magnaporthe oryzae. Here, a novel ß-1,6-glucanase from M. oryzae, MoGlu16, was cloned and expressed in Pichia pastoris. The enzyme was highly active on pustulan, with a specific activity of 219.0 U/mg at pH 5.0 and 50°C, and showed great selectivity for continuous ß-1,6-glycosidic bonding polysaccharides. Based on this, ß-1,6-glucan was selectively visualized in the vegetative hyphae, conidia and bud tubes of M. oryzae using a hydrolytically inactive GFP-tagged MoGlu16 with point mutations at the catalytic position (His-MoGlu16E236A-Gfp). The spore germination and appressorium formation were significantly inhibited after incubation of 105/ml conidia with 0.03 µg/µl MoGlu16. Mycelia treated with MoGlu16 produced reactive oxygen species and triggered the cell wall integrity pathway, increasing the expression levels of genes involved in cell wall polysaccharide synthesis. These results revealed that MoGlu16 participated in the remodeling of cell wall in M. oryzae, laying a foundation for the analysis of cell wall structure.

20.
Dev Cell ; 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-39025063

RESUMEN

The ubiquitin-proteasome system (UPS) plays crucial roles in cellular processes including plant growth, development, and stress responses. In this study, we report that a pair of E3 ubiquitin ligases, AvrPiz-t-interaction protein 6 (APIP6) and IPA1-interaction protein 1 (IPI1), intricately target early flowering3 (ELF3) paralogous proteins to control rice immunity and flowering. APIP6 forms homo-oligomers or hetero-oligomers with IPI1. Both proteins interact with OsELF3-2, promoting its degradation to positively control resistance against the rice blast fungus (Magnaporthe oryzae). Intriguingly, overexpression of IPI1 in Nipponbare caused significantly late-flowering phenotypes similar to the oself3-1 mutant. Except for late flowering, oself3-1 enhances resistance against M. oryzae. IPI1 also interacts with and promotes the degradation of OsELF3-1, a paralog of OsELF3-2. Notably, IPI1 and APIP6 synergistically modulate OsELF3s degradation, finely tuning blast disease resistance by targeting OsELF3-2, while IPI1 controls both disease resistance and flowering by targeting OsELF3-1. This study unravels multiple functions for a pair of E3 ligases in rice.

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