RESUMO
Magnaporthe oryzae is a devastating fungal pathogen that causes the rice blast disease worldwide. The post-translational modification of ADP-ribosylation holds significant importance in various fundamental biological processes. However, the specific function of this modification in M. oryzae remains unknown. This study revealed that Poly(ADP-ribosyl)ation (PARylation) executes a critical function in M. oryzae. M. oryzae Poly(ADP-ribose) polymerase 1 (PARP1) exhibits robust PARylation activity. Disruption of PARylation by PARP1 knock-out or chemical inhibition reveals its involvement in M. oryzae virulence, particularly in appressorium formation. Furthermore, we identified two M. oryzae 14-3-3 proteins, GRF1 and GRF2, as substrates of PARP1. Deletion of GRF1 or GRF2 results in delayed and dysfunctional appressorium, diminished plant penetration, and reduced virulence of the fungus. Biochemical and genetic evidence suggest that PARylation of 14-3-3s is essential for its function in M. oryzae virulence. Moreover, PARylation regulates 14-3-3 dimerization and is required for the activation of the mitogen-activated protein kinases (MAPKs), Pmk1 and Mps1. GRF1 interacts with both Mst7 and Pmk1, and bridges their interaction in a PARylation-dependent manner. This study unveils a distinctive mechanism that PARylation of 14-3-3 proteins controls appressorium formation through MAPK activation, and could facilitate the development of new strategies of rice blast disease control.
Assuntos
Proteínas 14-3-3 , Proteínas Fúngicas , Oryza , Doenças das Plantas , Proteínas 14-3-3/metabolismo , Proteínas 14-3-3/genética , Virulência , Oryza/microbiologia , Doenças das Plantas/microbiologia , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , ADP-Ribosilação , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Ascomicetos/patogenicidade , Ascomicetos/genética , Ascomicetos/metabolismo , Magnaporthe/patogenicidade , Magnaporthe/genética , Magnaporthe/metabolismo , Processamento de Proteína Pós-TraducionalRESUMO
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.
Assuntos
Resistência à Doença , Variação Genética , Oryza , Doenças das Plantas , Oryza/microbiologia , Oryza/imunologia , Oryza/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/imunologia , Resistência à Doença/genética , Locos de Características Quantitativas/genética , Genes de Plantas/genética , Ascomicetos/genética , Ascomicetos/patogenicidade , Ascomicetos/fisiologia , Proteínas de Plantas/genética , Magnaporthe/genética , Magnaporthe/patogenicidade , Magnaporthe/fisiologiaRESUMO
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.
Assuntos
Bacillus , Agentes de Controle Biológico , Oryza , Doenças das Plantas , Bacillus/genética , Bacillus/metabolismo , Oryza/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Agentes de Controle Biológico/farmacologia , Agentes de Controle Biológico/metabolismo , Metabolismo Secundário , Antibiose , Microbiologia do Solo , Ascomicetos/genética , Ascomicetos/metabolismo , Controle Biológico de Vetores , Magnaporthe/genética , Magnaporthe/metabolismoRESUMO
Bioengineering of plant immune receptors has emerged as a key strategy for generating novel disease resistance traits to counteract the expanding threat of plant pathogens to global food security. However, current approaches are limited by rapid evolution of plant pathogens in the field and may lack durability when deployed. Here, we show that the rice nucleotide-binding, leucine-rich repeat (NLR) immune receptor Pik-1 can be engineered to respond to a conserved family of effectors from the multihost blast fungus pathogen Magnaporthe oryzae. We switched the effector binding and response profile of the Pik NLR from its cognate rice blast effector AVR-Pik to the host-determining factor pathogenicity toward weeping lovegrass 2 (Pwl2) by installing a putative host target, OsHIPP43, in place of the native integrated heavy metal-associated domain (generating Pikm-1OsHIPP43). This chimeric receptor also responded to other PWL alleles from diverse blast isolates. The crystal structure of the Pwl2/OsHIPP43 complex revealed a multifaceted, robust interface that cannot be easily disrupted by mutagenesis, and may therefore provide durable, broad resistance to blast isolates carrying PWL effectors in the field. Our findings highlight how the host targets of pathogen effectors can be used to bioengineer recognition specificities that have more robust properties compared to naturally evolved disease resistance genes.
Assuntos
Proteínas Fúngicas , Proteínas NLR , Oryza , Doenças das Plantas , Proteínas de Plantas , Oryza/microbiologia , Oryza/imunologia , Doenças das Plantas/microbiologia , Doenças das Plantas/imunologia , Proteínas NLR/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/imunologia , Proteínas de Plantas/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/imunologia , Interações Hospedeiro-Patógeno/imunologia , Resistência à Doença/imunologia , Imunidade Vegetal , Bioengenharia/métodos , Magnaporthe/imunologia , Magnaporthe/genética , Magnaporthe/metabolismo , Ligação Proteica , Receptores Imunológicos/metabolismo , AscomicetosRESUMO
Rice blast, caused by Magnaporthe oryzae, is a devastating fungal disease worldwide. Pydiflumetofen (Pyd) is a new succinate dehydrogenase inhibitor (SDHI) that exhibited anti-fungal activity against M. oryzae. However, control of rice blast by Pyd and risk of resistance to Pyd are not well studied in this pathogen. The baseline sensitivity of 109 M. oryzae strains to Pyd was determined using mycelial growth rate assay, with EC50 values ranging from 0.291 to 2.1313 µg/mL, and an average EC50 value of 1.1005 ± 0.3727 µg/mL. Totally 28 Pyd-resistant (PydR) mutants with 15 genotypes of point mutations in succinate dehydrogenase (SDH) complex were obtained, and the resistance level could be divided into three categories of very high resistance (VHR), high resistance (HR) and moderate resistance (MR) with the resistance factors (RFs) of >1000, 105.74-986.13 and 81.92-99.48, respectively. Molecular docking revealed that all 15 mutations decreased the binding-force score for the affinity between Pyd and target subunits, which further confirmed that these 15 genotypes of point mutations were responsible for the resistance to Pyd in M. oryzae. There was positive cross resistance between Pyd and other SDHIs, such as fluxapyroxad, penflufen or carboxin, while there was no cross-resistance between Pyd and carbendazim, prochloraz or azoxystrobin in M. oryzae, however, PydR mutants with SdhBP198Q, SdhCL66F or SdhCL66R genotype were still sensitive to the other 3 SDHIs, indicating lack of cross resistance. The results of fitness study revealed that the point mutations in MoSdhB/C/D genes might reduce the hyphae growth and sporulation, but could improve the pathogenicity in M. oryzae. Taken together, the risk of resistance to Pyd might be moderate to high, and it should be used as tank-mixtures with other classes of fungicides to delay resistance development when it is used for the control of rice blast in the field.
Assuntos
Substituição de Aminoácidos , Farmacorresistência Fúngica , Fungicidas Industriais , Succinato Desidrogenase , Succinato Desidrogenase/genética , Succinato Desidrogenase/antagonistas & inibidores , Succinato Desidrogenase/metabolismo , Farmacorresistência Fúngica/genética , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Simulação de Acoplamento Molecular , Magnaporthe/efeitos dos fármacos , Magnaporthe/genética , Mutação Puntual , Oryza/microbiologia , AscomicetosRESUMO
Magnaporthe oryzae is a rice blast pathogen that seriously threatens rice yield. Benzovindiflupyr is a succinate dehydrogenase inhibitor (SDHI) fungicide that effectively controls many crop diseases. Benzovindiflupyr has a strong inhibitory effect on M. oryzae; however, control of rice blast by benzovindiflupyr and risk of resistance to benzovindiflupyr are not well studied in this pathogen. In this study, six benzovindiflupyr-resistant strains were obtained by domestication induced in the laboratory. The MoSdhBH245D mutation was the cause of M. oryzae resistance to benzovindiflupyr, which was verified through succinate dehydrogenase (SDH) activity assays, molecular docking, and site-specific mutations. Survival fitness analysis showed no significant difference between the benzovindiflupyr-resistant and parent strains. Positive cross-resistance to benzovindiflupyr and other SDHIs and negative cross-resistance to azoxystrobin were observed. Therefore, the risk of benzovindiflupyr resistance in M. oryzae might be medium to high. It should be combined with other classes of fungicides (tebuconazole and azoxystrobin) to slow the development of resistance.
Assuntos
Farmacorresistência Fúngica , Fungicidas Industriais , Mutação , Succinato Desidrogenase , Succinato Desidrogenase/genética , Succinato Desidrogenase/antagonistas & inibidores , Fungicidas Industriais/farmacologia , Farmacorresistência Fúngica/genética , Doenças das Plantas/microbiologia , Magnaporthe/efeitos dos fármacos , Magnaporthe/genética , Simulação de Acoplamento Molecular , Oryza/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Estrobilurinas/farmacologia , AscomicetosRESUMO
The cell wall is the first barrier against external adversity and plays roles in maintaining normal physiological functions of fungi. Previously, we reported a nucleosome assembly protein, MoNap1, in Magnaporthe oryzae that plays a role in cell wall integrity (CWI), stress response, and pathogenicity. Moreover, MoNap1 negatively regulates the expression of MoSMI1 encoded by MGG_03970. Here, we demonstrated that deletion of MoSMI1 resulted in a significant defect in appressorium function, CWI, cell morphology, and pathogenicity. Further investigation revealed that MoSmi1 interacted with MoOsm1 and MoMps1 and affected the phosphorylation levels of MoOsm1, MoMps1, and MoPmk1, suggesting that MoSmi1 regulates biological functions by mediating mitogen-activated protein kinase (MAPK) signalling pathway in M. oryzae. In addition, transcriptome data revealed that MoSmi1 regulates many infection-related processes in M. oryzae, such as membrane-related pathway and oxidation reduction process. In conclusion, our study demonstrated that MoSmi1 regulates CWI by mediating the MAPK pathway to affect development and pathogenicity of M. oryzae.
Assuntos
Proteínas Fúngicas , Proteínas Quinases Ativadas por Mitógeno , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Virulência/genética , Regulação Fúngica da Expressão Gênica , Doenças das Plantas/microbiologia , Parede Celular/metabolismo , Sistema de Sinalização das MAP Quinases , Oryza/microbiologia , Fosforilação , Magnaporthe/patogenicidade , Magnaporthe/genética , AscomicetosRESUMO
C2H2 zinc effectors are a class of pathogen proteins that play a dual role in plant-pathogen interactions, promoting pathogenicity and enhancing plant defense. In our previous research, we identified Magnaporthe oryzae Systemic Defense Trigger 1 (MoSDT1) as a C2H2 zinc effector that activates rice (Oryza sativa) defense when overexpressed in rice. However, its regulatory roles in pathogenicity and defense require further investigation. In this study, we generated an MoSDT1 overexpressing strain and 2 knockout strains of M. oryzae to assess the impact of MoSDT1 on pathogenicity, rice defense, and phenotypic characteristics. Our analyses revealed that MoSDT1 substantially influenced vegetative growth, conidia size, and conidiation, and was crucial for the virulence of M. oryzae while suppressing rice defense. MoSDT1 localized to the nucleus and cytoplasm of rice, either dependent or independent of M. oryzae delivery. Through RNA-seq, scRNA-seq, and ChIP-seq, we identified that MoSDT1 modulates rice defense by regulating the phosphorylation and ubiquitination of various rice signaling proteins, including transcription factors, transcription repressors, kinases, phosphatases, and the ubiquitin system. These findings provide valuable insights into the regulatory mechanisms of C2H2 zinc finger effector proteins and offer important foundational information for utilizing their target genes in disease resistance breeding and the design of targets for disease management.
Assuntos
Oryza , Doenças das Plantas , Oryza/microbiologia , Oryza/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Virulência/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Interações Hospedeiro-Patógeno/genética , Magnaporthe/patogenicidade , Magnaporthe/genética , Magnaporthe/fisiologia , Resistência à Doença/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , AscomicetosRESUMO
Filamentous plant pathogens deliver effector proteins into host cells to suppress host defence responses and manipulate metabolic processes to support colonization. Understanding the evolution and molecular function of these effectors provides knowledge about pathogenesis and can suggest novel strategies to reduce damage caused by pathogens. However, effector proteins are highly variable, share weak sequence similarity and, although they can be grouped according to their structure, only a few structurally conserved effector families have been functionally characterized to date. Here, we demonstrate that Zinc-finger fold (ZiF) secreted proteins form a functionally diverse effector family in the blast fungus Magnaporthe oryzae. This family relies on the Zinc-finger motif for protein stability and is ubiquitously present in blast fungus lineages infecting 13 different host species, forming different effector tribes. Homologs of the canonical ZiF effector, AVR-Pii, from rice infecting isolates are present in multiple M. oryzae lineages. Wheat infecting strains of the fungus also possess an AVR-Pii like allele that binds host Exo70 proteins and activates the immune receptor Pii. Furthermore, ZiF tribes may vary in the proteins they bind to, indicating functional diversification and an intricate effector/host interactome. Altogether, we uncovered a new effector family with a common protein fold that has functionally diversified in lineages of M. oryzae. This work expands our understanding of the diversity of M. oryzae effectors, the molecular basis of plant pathogenesis and may ultimately facilitate the development of new sources for pathogen resistance.
Assuntos
Proteínas Fúngicas , Doenças das Plantas , Dedos de Zinco , Doenças das Plantas/microbiologia , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Interações Hospedeiro-Patógeno , Oryza/microbiologia , Ascomicetos/genética , Ascomicetos/metabolismo , Magnaporthe/genética , Magnaporthe/metabolismo , FilogeniaRESUMO
A novel negative-sense single-stranded RNA mycovirus, designated as "Magnaporthe oryzae mymonavirus 1" (MoMNV1), was identified in the rice blast fungus Magnaporthe oryzae isolate NJ39. MoMNV1 has a single genomic RNA segment consisting of 10,515 nucleotides, which contains six open reading frames. The largest open reading frame contains 5837 bases and encodes an RNA replicase. The six open reading frames have no overlap and are arranged linearly on the genome, but the spacing of the genes is small, with a maximum of 315 bases and a minimum of 80 bases. Genome comparison and phylogenetic analysis indicated that MoMNV1 is a new member of the genus Penicillimonavirus of the family Mymonaviridae.
Assuntos
Micovírus , Genoma Viral , Fases de Leitura Aberta , Oryza , Filogenia , Doenças das Plantas , Vírus de RNA , RNA Viral , Vírus de RNA/genética , Vírus de RNA/isolamento & purificação , Vírus de RNA/classificação , Micovírus/genética , Micovírus/isolamento & purificação , Micovírus/classificação , Oryza/microbiologia , Oryza/virologia , Doenças das Plantas/microbiologia , Doenças das Plantas/virologia , RNA Viral/genética , Ascomicetos/virologia , Ascomicetos/genética , Proteínas Virais/genética , Magnaporthe/virologia , Magnaporthe/genéticaRESUMO
Reverse genetic approaches are common tools in genomics for elucidating gene functions, involving techniques such as gene deletion followed by screening for aberrant phenotypes. If the generation of gene deletion mutants fails, the question arises whether the failure stems from technical issues or because the gene of interest (GOI) is essential, meaning that the deletion causes lethality. In this report, we introduce a novel method for assessing gene essentiality using the phytopathogenic ascomycete Magnaporthe oryzae. The method is based on the observation that telomere vectors are lost in transformants during cultivation without selection pressure. We tested the hypothesis that essential genes can be identified in deletion mutants co-transformed with a telomere vector. The M. oryzae gene MoPKC, described in literature as essential, was chosen as GOI. Using CRISPR/Cas9 technology transformants with deleted GOI were generated and backed up by a telomere vector carrying a copy of the GOI and conferring fenhexamid resistance. Transformants in which the GOI deletion in the genome was not successful lost the telomere vector on media without fenhexamid. In contrast, transformants with confirmed GOI deletion retained the telomere vector even in absence of fenhexamid selection. In the latter case, the maintenance of the telomere indicates that the GOI is essential for the surveillance of the fungi, as it would have been lost otherwise. The method presented here allows to test for essentiality of genes when no mutants can be obtained from gene deletion approaches, thereby expanding the toolbox for studying gene function in ascomycetes.
Assuntos
Ascomicetos , Genes Essenciais , Vetores Genéticos , Fenótipo , Telômero , Telômero/genética , Vetores Genéticos/genética , Sistemas CRISPR-Cas/genética , Genes Fúngicos/genética , Deleção de Genes , Magnaporthe/genética , Magnaporthe/patogenicidadeRESUMO
Rice blast is a highly destructive crop disease that requires the interplay of three essential factors: the virulent blast fungus, the susceptible rice plant, and favorable environmental conditions. Although previous studies have focused mainly on the pathogen and rice, recent research has shed light on the molecular mechanisms by which the blast fungus and environmental conditions regulate host resistance and contribute to blast disease outbreaks. This review summarizes significant achievements in understanding the sophisticated modulation of blast resistance by Magnaporthe oryzae effectors and the dual regulatory mechanisms by which environmental conditions influence rice resistance and virulence of the blast fungus. Furthermore, it emphasizes potential strategies for developing blast-resistant rice varieties to effectively control blast disease.
Assuntos
Resistência à Doença , Interações Hospedeiro-Patógeno , Oryza , Doenças das Plantas , Oryza/microbiologia , Oryza/imunologia , Doenças das Plantas/microbiologia , Doenças das Plantas/imunologia , Resistência à Doença/genética , Virulência , Interações Hospedeiro-Patógeno/imunologia , Blastomicose/microbiologia , Blastomicose/imunologia , Ascomicetos/patogenicidade , Ascomicetos/genética , Magnaporthe/patogenicidade , Magnaporthe/genética , Meio AmbienteRESUMO
Polarized growth is critical for the development of filamentous phytopathogens, and the CHY-type zinc finger protein Chy1 regulates microtubule assembly to influence polarized growth and thereby affect plant infections. However, the biological role of a Chy1 homolog MoChy1 remains unknown in Magnaporthe oryzae. We found here that the MoChy1-GFP was distributed in the cytoplasm outside the vacuole in hyphae and localized mainly to the vacuole compartments as the appressorium matured. The Mochy1 mutants showed an extremely slow growth rate, curved and branched mycelium, reduced conidiation, and a smaller size in the appressorium. Meanwhile, the Mochy1 mutants showed increased sensitivity to benomyl, damaged microtubule cytoskeleton, and mislocalized polarisome protein MoSpa2 and chitin synthase MoChs6 in hyphae. Compared to Guy11, the Mochy1 mutants exhibited increased sensitivity to H2O2, impaired ability to eliminate host-derived ROS and reduced penetration into host plants, resulting in a strong reduction in pathogenicity of Mochy1 mutants. Furthermore, the Mochy1 mutants also exhibited defects in chitin distribution, osmotic stress tolerance, and septin ring organization during appressorium differentiation and fungal development. Nonselective autophagy was negatively regulated in Mochy1 mutants compared to Guy11. In summary, MoChy1 plays multiple roles in fungal polar growth and full virulence of M. oryzae.
Assuntos
Autofagia , Proteínas Fúngicas , Esporos Fúngicos , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/genética , Mutação , Dedos de Zinco , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Virulência/genética , Magnaporthe/patogenicidade , Magnaporthe/genética , Magnaporthe/crescimento & desenvolvimento , Magnaporthe/metabolismo , Doenças das Plantas/microbiologia , Oryza/microbiologia , Regulação Fúngica da Expressão Gênica , AscomicetosRESUMO
The fungal disease caused by Magnaporthe oryzae is one of the most devastating diseases that endanger many crops worldwide. Evidence shows that sexual reproduction can be advantageous for fungal diseases as hybridization facilitates host-jumping. However, the pervasive clonal lineages of M. oryzae observed in natural fields contradict this expectation. A better understanding of the roles of recombination and the fungi-specific repeat-induced point mutation (RIP) in shaping its evolutionary trajectory is essential to bridge this knowledge gap. Here we systematically investigate the RIP and recombination landscapes in M. oryzae using a whole genome sequencing data from 252 population samples and 92 cross progenies. Our data reveal that the RIP can robustly capture the population history of M. oryzae, and we provide accurate estimations of the recombination and RIP rates across different M. oryzae clades. Significantly, our results highlight a parent-of-origin bias in both recombination and RIP rates, tightly associating with their sexual potential and variations of effector proteins. This bias suggests a critical trade-off between generating novel allelic combinations in the sexual cycle to facilitate host-jumping and stimulating transposon-associated diversification of effectors in the asexual cycle to facilitate host coevolution. These findings provide unique insights into understanding the evolution of blast fungus.
Assuntos
Mutação Puntual , Recombinação Genética , Reprodução Assexuada , Recombinação Genética/genética , Mutação Puntual/genética , Reprodução Assexuada/genética , Evolução Molecular , Doenças das Plantas/microbiologia , Doenças das Plantas/genética , Genoma Fúngico/genética , Magnaporthe/genética , Magnaporthe/fisiologia , Magnaporthe/patogenicidade , AscomicetosRESUMO
Dynamic transposition of transposable elements (TEs) in fungal pathogens has significant impact on genome stability, gene expression, and virulence to the host. In Magnaporthe oryzae, genome plasticity resulting from TE insertion is a major driving force leading to the rapid evolution and diversification of this fungus. Despite their importance in M. oryzae population evolution and divergence, our understanding of TEs in this context remains limited. Here, we conducted a genome-wide analysis of TE transposition dynamics in the 11 most abundant TE families in M. oryzae populations. Our results show that these TEs have specifically expanded in recently isolated M. oryzae rice populations, with the presence/absence polymorphism of TE insertions highly concordant with population divergence on Geng/Japonica and Xian/Indica rice cultivars. Notably, the genes targeted by clade-specific TEs showed clade-specific expression patterns and are involved in the pathogenic process, suggesting a transcriptional regulation of TEs on targeted genes. Our study provides a comprehensive analysis of TEs in M. oryzae populations and demonstrates a crucial role of recent TE bursts in adaptive evolution and diversification of the M. oryzae rice-infecting lineage. IMPORTANCE: Magnaporthe oryzae is the causal agent of the destructive blast disease, which caused massive loss of yield annually worldwide. The fungus diverged into distinct clades during adaptation toward the two rice subspecies, Xian/Indica and Geng/Japonica. Although the role of TEs in the adaptive evolution was well established, mechanisms underlying how TEs promote the population divergence of M. oryzae remain largely unknown. In this study, we reported that TEs shape the population divergence of M. oryzae by differentially regulating gene expression between Xian/Indica-infecting and Geng/Japonica-infecting populations. Our results revealed a TE insertion-mediated gene expression adaption that led to the divergence of M. oryzae population infecting different rice subspecies.
Assuntos
Elementos de DNA Transponíveis , Evolução Molecular , Genoma Fúngico , Oryza , Doenças das Plantas , Elementos de DNA Transponíveis/genética , Oryza/microbiologia , Doenças das Plantas/microbiologia , Virulência/genética , Variação Genética , Ascomicetos/genética , Ascomicetos/classificação , Ascomicetos/patogenicidade , Magnaporthe/genética , Magnaporthe/patogenicidade , Magnaporthe/classificaçãoRESUMO
Rice blast, caused by rice blast fungus (Magnaporthe oryzae), is a global threat to food security, with up to 50% yield losses. Panicle blast is a severe form of rice blast, and disease responses vary between cultivars with different genotypes. Reactive oxygen species (ROS)-mediated signaling reactions and the phenylpropanoid pathway are important defense mechanisms involved in recognizing and resisting against fungal infection. To understand rice-M. oryzae interactions in resistant and susceptible cultivars, we determined dynamic changes in the activities of five defense-related enzymes in resistant cultivar jingsui 18 and susceptible cultivar jinyuan 899 infected with M. oryzae from 4 to 25 days after infection. We then performed untargeted metabolomics analyses to profile the metabolomes of the cultivars under infected and non-infected conditions. Dynamic changes in the activities of five defense-related enzymes were closely related to panicle blast resistance in rice. Metabolome data analysis identified 634 differentially accumulated metabolites (DAMs) between resistant and susceptible cultivars following infection, potentially explaining differences in disease response between varieties. The most enriched DAMs were associated with lipids and lipid-like molecules, phenylpropanoids and polyketides, organoheterocyclic compounds, organic acids and derivatives, and lignans, neolignans, and related compounds. Multiple metabolic pathways are involved in resistance to panicle blast in rice, including biosynthesis of other secondary metabolites, amino acid metabolism, lipid metabolism, phenylpropanoid biosynthesis, arachidonic acid metabolism, arginine biosynthesis, tyrosine metabolism, tryptophan metabolism, tyrosine and tryptophan biosynthesis, lysine biosynthesis, and oxidative phosphorylation.
Assuntos
Ascomicetos , Magnaporthe , Oryza , Resistência à Doença/genética , Oryza/genética , Magnaporthe/genética , Triptofano/metabolismo , Tirosina/metabolismo , Doenças das Plantas/microbiologiaRESUMO
Fungi use the accessory gene content of their pangenomes to adapt to their environments. While gene presence-absence variation contributes to shaping accessory gene reservoirs, the genomic contexts that shape these events remain unclear. Since pangenome studies are typically species-wide and do not analyze different populations separately, it is yet to be uncovered whether presence-absence variation patterns and mechanisms are consistent across populations. Fungal plant pathogens are useful models for studying presence-absence variation because they rely on it to adapt to their hosts, and members of a species often infect distinct hosts. We analyzed gene presence-absence variation in the blast fungus, Magnaporthe oryzae (syn. Pyricularia oryzae), and found that presence-absence variation genes involved in host-pathogen and microbe-microbe interactions may drive the adaptation of the fungus to its environment. We then analyzed genomic and epigenomic features of presence-absence variation and observed that proximity to transposable elements, gene GC content, gene length, expression level in the host, and histone H3K27me3 marks were different between presence-absence variation genes and conserved genes. We used these features to construct a model that was able to predict whether a gene is likely to experience presence-absence variation with high precision (86.06%) and recall (92.88%) in M. oryzae. Finally, we found that presence-absence variation genes in the rice and wheat pathotypes of M. oryzae differed in their number and their genomic context. Our results suggest that genomic and epigenomic features of gene presence-absence variation can be used to better understand and predict fungal pangenome evolution. We also show that substantial intra-species variation can exist in these features.
Assuntos
Ascomicetos , Magnaporthe , Oryza , Magnaporthe/genética , Genômica , Oryza/genética , Oryza/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologiaRESUMO
Rice blast, caused by the plant pathogenic fungus Magnaporthe oryzae, is a destructive disaster all over the earth that causes enormous losses in crop production. Sphingolipid, an important biological cell membrane lipid, is an essential structural component in the plasma membrane (PM) and has several biological functions, including cell mitosis, apoptosis, stress resistance, and signal transduction. Previous studies have suggested that sphingolipid and its derivatives play essential roles in the virulence of plant pathogenic fungi. However, the functions of sphingolipid biosynthesis-related proteins are not fully understood. In this article, we identified a key sphingolipid synthesis enzyme, MoDes1, and found that it is engaged in cell development and pathogenicity in M. oryzae. Deletion of MoDES1 gave rise to pleiotropic defects in vegetative growth, conidiation, plant penetration, and pathogenicity. MoDes1 is also required for lipid homeostasis and participates in the cell wall integrity (CWI) and Osm1-MAPK pathways. Notably, our results showed that there is negative feedback in the TORC2 signaling pathway to compensate for the decreased sphingolipid level due to the knockout of MoDES1 by regulating the phosphorylated Ypk1 level and PM tension. Furthermore, protein structure building has shown that MoDes1 is a potential drug target. These findings further refine the function of Des1 and deepen our understanding of the sphingolipid biosynthesis pathway in M. oryzae, laying a foundation for developing novel and specific drugs for rice blast control.
Assuntos
Magnaporthe , Oryza , Virulência/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Esfingolipídeos/metabolismo , Oryza/microbiologia , Magnaporthe/genética , Membrana Celular/metabolismo , Doenças das Plantas/microbiologia , Esporos Fúngicos , Regulação Fúngica da Expressão GênicaRESUMO
The fungal pathogen, Magnaporthe oryzae Triticum pathotype, causing wheat blast disease was first identified in South America and recently spread across continents to South Asia and Africa. Here, we studied the genetic relationship among isolates found on the three continents. Magnaporthe oryzae strains closely related to a South American field isolate B71 were found to have caused the wheat blast outbreaks in South Asia and Africa. Genomic variation among isolates from the three continents was examined using an improved B71 reference genome and whole-genome sequences. We found strong evidence to support that the outbreaks in Bangladesh and Zambia were caused by the introductions of genetically separated isolates, although they were all close to B71 and, therefore, collectively referred to as the B71 branch. In addition, B71 branch strains carried at least one supernumerary mini-chromosome. Genome assembly of a Zambian strain revealed that its mini-chromosome was similar to the B71 mini-chromosome but with a high level of structural variation. Our findings show that while core genomes of the multiple introductions are highly similar, the mini-chromosomes have undergone marked diversification. The maintenance of the mini-chromosome and rapid genomic changes suggest the mini-chromosomes may serve important virulence or niche adaptation roles under diverse environmental conditions.
Assuntos
Ascomicetos , Magnaporthe , Triticum , Triticum/genética , Bangladesh/epidemiologia , Zâmbia/epidemiologia , Magnaporthe/genética , Cromossomos , Doenças das Plantas/microbiologiaRESUMO
The differentiation of specialized infection cells, called appressoria, from polarized germ tubes of the blast fungus Magnaporthe oryzae, requires remarkable remodeling of cell polarity and architecture, yet our understanding of this process remains incomplete. Here we investigate the behavior and role of cell-end marker proteins in appressorium remodeling and hyphal branch emergence. We show that the SH3 domain-containing protein Tea4 is required for the normal formation of an F-actin ring at Tea1-GFP-labeled polarity nodes, which contributes to the remodeling of septin structures and repolarization of the appressorium. Further, we show that Tea1 localizes to a cortical structure during hyphal septation which, unlike contractile septin rings, persists after septum formation, and, in combination with other polarity determinants, likely spatially regulates branch emergence. Genetic loss of Tea4 leads to mislocalization of Tea1 at the hyphal apex and with it, impaired growth directionality. In contrast, Tea1 is largely depleted from septation events in Δtea4 mutants and branching and septation are significantly reduced. Together, our data provide new insight into polarity remodeling during infection-related and vegetative growth by the blast fungus.