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1.
PLoS One ; 15(9): e0239001, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915896

RESUMO

White-nose syndrome is a fungal disease responsible for the rapid decline of North American bat populations. This study addressed a novel method for inactivating Pseudogymnoascus destructans, the causative agent of WNS, using ultraviolet A (UVA) or B (UVB) radiation in combination with methoxsalen, a photosensitizer from the furanocoumarin family of compounds. Fungal spore suspensions were diluted in micromolar concentrations of methoxsalen (50-500 µM), then exposed to fixed doses of UVA radiation (500-5000 mJ/cm2), followed by plating on germination media. These plates were examined for two to four weeks for evidence of spore germination or inactivation, along with resultant growth or inhibition of P. destructans colonies. Pretreatment of fungal spores with low doses of methoxsalen resulted in a UVA dose-dependent inactivation of the P. destructans spores. All doses of methoxsalen paired with 500 mJ/cm2 of UVA led to an approximate two-log10 (~99%) reduction in spore viability, and when paired with 1000 mJ/cm2, a four-log10 or greater (>99.99%) reduction in spore viability was observed. Additionally, actively growing P. destructans colonies treated directly with methoxsalen and either UVA or UVB radiation demonstrated UV dose-dependent inhibition and termination of colony growth. This novel approach of using a photosensitizer in combination with UV radiation to control fungal growth may have broad, practical application in the future.


Assuntos
Ascomicetos/efeitos da radiação , Quirópteros/microbiologia , Metoxaleno/administração & dosagem , Micoses/veterinária , Fármacos Fotossensibilizantes/administração & dosagem , Terapia Ultravioleta , Animais , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Micoses/radioterapia , Esporos Fúngicos/patogenicidade , Esporos Fúngicos/efeitos da radiação , Síndrome
2.
Arch Virol ; 165(10): 2401-2404, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32757057

RESUMO

A novel mycovirus, named "Corynespora cassiicola bipartite mycovirus 1" (CcBV1), was isolated from a phytopathogenic fungus, Corynespora cassiicola, the causal agent of rubber leaf fall disease. The nucleotide sequence of the complete genome of CcBV1, which consists of two double-stranded RNA (dsRNA) segments, was determined. The first dsRNA is 2,002 bp in length and contains a single open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) (69 kDa), while the second is 1,738 bp in length and contains a single ORF encoding a hypothetical protein of unknown function, with an approximately molecular weight of 36 kDa. The amino acid sequences of the both deduced proteins are most similar (58.9% and 45.1% identity, respectively) to those of Cryphonectria parasitica bipartite mycovirus 1 (CpBV1). Phylogenetic analysis indicated that CcBV1 clusters together with CpBV1 and other unassigned dsRNA mycoviruses. To the best of our knowledge, this represents the first report of a mycovirus infecting C. cassiicola.


Assuntos
Ascomicetos/virologia , Micovírus/genética , Genoma Viral , Filogenia , RNA de Cadeia Dupla/genética , RNA Viral/genética , Ascomicetos/patogenicidade , Sequência de Bases , China , Micovírus/classificação , Micovírus/isolamento & purificação , Fases de Leitura Aberta , Doenças das Plantas/microbiologia , Plantas/microbiologia , RNA Replicase/genética , Alinhamento de Sequência , Proteínas Virais/genética , Sequenciamento Completo do Genoma
3.
Mol Plant Microbe Interact ; 33(11): 1315-1329, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32815478

RESUMO

The role of NADPH oxidases (NOXs) in pathogenesis and development in the Curvularia leaf spot agent Curvularia lunata remains poorly understood. In this study, we identified C. lunata ClNOX2, which localized to the plasma membrane and was responsible for reactive oxygen species (ROS) generation. Scavenging the ROS production inhibited the conidial germination and appressorial formation. The ClNOX2 and ClBRN1 deletion mutants were defective in 1,8-dihydroxynaphthalene (DHN) melanin accumulation, appressorial formation, and cellulase synthesis and exhibited lower virulence. However, disruption of the ClNOX2 and ClBRN1 genes facilitated hyphal growth, enhanced stress adaptation to cell-wall-disrupting agents, and promoted developmental processes such as conidiation, conidial germination, and pseudothecium and ascus formation. Interestingly, loss of ClM1, the cell wall integrity (CWI) mitogen-activated protein kinase gene in C. lunata, led to morphology and pathogenicity phenotypes similar to ClNOX2 and ClBRN1 deletion mutants such as abnormal conidia, fewer appressoria, less melanin, increased hyphal growth, and enhanced tolerance to Congo red (CR). These results indicated that the ClNOX2 gene plays an important role in C. lunata development and virulence via regulating intracellular DHN melanin biosynthesis. Quantitative reverse-transcription PCR revealed that the ClNOX2-related ROS signaling pathway and ClM1-mediated CWI signaling pathway are cross-linked in regulating DHN melanin biosynthesis. Our findings provide new insights into how ClNOX2 participates in pathogenesis and development in hemibiotrophic plant fungal pathogens.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Ascomicetos/enzimologia , Melaninas/biossíntese , NADPH Oxidases , Doenças das Plantas/microbiologia , Ascomicetos/patogenicidade , Proteínas Fúngicas/genética , NADPH Oxidases/genética , Espécies Reativas de Oxigênio/metabolismo , Esporos Fúngicos , Virulência
4.
PLoS One ; 15(8): e0235355, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817671

RESUMO

The Arbuscular mycorrhizal fungi (AMF) (Funneliformis mosseae), are the most widely distributed symbiont assisting plants to overcome counteractive environmental conditions. In order to improve the sustainability and the activity of AMF, the use of nanotechnology was important. The main objective of this study was to investigate the effect of titanium dioxide nanoparticles (TiO2NPs) on the activity of AMF in common bean roots as well as its activity under salinity stress using morphological and molecular methods. The activity of AMF colonization has increased in the presence of TiO2NPs especially for arbuscule activity (A%), which increased three times with the presence of TiO2NPs. The improvement rate of Funneliformis mosseae on plant growth increased from 180% to 224% of control at the lowest level of salinity and increased from 48% to 130% at higher salinity level, respectively. The AMF dependencies for plant dry biomass increased in the presence of TiO2NPs from 277% in the absence of salinity to 465 and 883% % at low and high salinity levels, respectively. The presence of AMF co-inoculated with TiO2NPs resulted in increasing the salinity tolerance of plants at all levels and reached 110% at salinity level of 100 mM NaCl. Quantitative colonization methods showed that the molecular intensity ratio and the relative density of paired inocula AMF Nest (NS) or chitin synthases gene (Chs) with TiO2NPs were higher significantly P.>0.05 than single inoculants of AMF gene in roots under the presence or the absence of salinity by about two folds and about 40%. Hence, the positive effect of TiO2NPs was confined to its effect on AMF not on bean plants itself.


Assuntos
Ascomicetos/patogenicidade , Nanopartículas Metálicas/química , Phaseolus/microbiologia , Tolerância ao Sal , Ascomicetos/efeitos dos fármacos , Ascomicetos/metabolismo , Quitina Sintase/genética , Quitina Sintase/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Nanopartículas Metálicas/microbiologia , Phaseolus/metabolismo , Simbiose , Titânio/química , Titânio/farmacologia
5.
PLoS One ; 15(7): e0235565, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614894

RESUMO

Powdery mildew is an important foliar disease of barley (Hordeum vulgare L.) caused by the biotrophic fungus Blumeria graminis f. sp. hordei (Bgh). The understanding of the resistance mechanism is essential for future resistance breeding. In particular, the identification of race-nonspecific resistance genes is important because of their regarded durability and broad-spectrum activity. We assessed the severity of powdery mildew infection on detached seedling leaves of 267 barley accessions using two poly-virulent isolates and performed a genome-wide association study exploiting 201 of these accessions. Two-hundred and fourteen markers, located on six barley chromosomes are associated with potential race-nonspecific Bgh resistance or susceptibility. Initial steps for the functional validation of four promising candidates were performed based on phenotype and transcription data. Specific candidate alleles were analyzed via transient gene silencing as well as transient overexpression. Microarray data of the four selected candidates indicate differential regulation of the transcription in response to Bgh infection. Based on our results, all four candidate genes seem to be involved in the responses to powdery mildew attack. In particular, the transient overexpression of specific alleles of two candidate genes, a potential arabinogalactan protein and the barley homolog of Arabidopsis thaliana's Light-Response Bric-a-Brac/-Tramtrack/-Broad Complex/-POxvirus and Zinc finger (AtLRB1) or AtLRB2, were top candidates of novel powdery mildew susceptibility genes.


Assuntos
Ascomicetos/genética , Hordeum/genética , Interações Hospedeiro-Patógeno/genética , Doenças das Plantas/microbiologia , Alelos , Ascomicetos/isolamento & purificação , Ascomicetos/patogenicidade , Análise por Conglomerados , Regulação da Expressão Gênica de Plantas , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Genótipo , Desequilíbrio de Ligação , Mucoproteínas/genética , Mucoproteínas/metabolismo , Fenótipo , Doenças das Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plântula/genética , Virulência/genética
6.
Mol Plant Microbe Interact ; 33(11): 1299-1314, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32720872

RESUMO

The fungal genus Plectosphaerella comprises species and strains with different lifestyles on plants, such as P. cucumerina, which has served as model for the characterization of Arabidopsis thaliana basal and nonhost resistance to necrotrophic fungi. We have sequenced, annotated, and compared the genomes and transcriptomes of three Plectosphaerella strains with different lifestyles on A. thaliana, namely, PcBMM, a natural pathogen of wild-type plants (Col-0), Pc2127, a nonpathogenic strain on Col-0 but pathogenic on the immunocompromised cyp79B2 cyp79B3 mutant, and P0831, which was isolated from a natural population of A. thaliana and is shown here to be nonpathogenic and to grow epiphytically on Col-0 and cyp79B2 cyp79B3 plants. The genomes of these Plectosphaerella strains are very similar and do not differ in the number of genes with pathogenesis-related functions, with the exception of secreted carbohydrate-active enzymes (CAZymes), which are up to five times more abundant in the pathogenic strain PcBMM. Analysis of the fungal transcriptomes in inoculated Col-0 and cyp79B2 cyp79B3 plants at initial colonization stages confirm the key role of secreted CAZymes in the necrotrophic interaction, since PcBMM expresses more genes encoding secreted CAZymes than Pc2127 and P0831. We also show that P0831 epiphytic growth on A. thaliana involves the transcription of specific repertoires of fungal genes, which might be necessary for epiphytic growth adaptation. Overall, these results suggest that in-planta expression of specific sets of fungal genes at early stages of colonization determine the diverse lifestyles and pathogenicity of Plectosphaerella strains.


Assuntos
Arabidopsis/microbiologia , Ascomicetos , Genes Fúngicos , Doenças das Plantas/microbiologia , Ascomicetos/genética , Ascomicetos/patogenicidade
7.
PLoS One ; 15(5): e0233366, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32421759

RESUMO

Sclerotinia stem rot (SSR) is a devastating fungal disease that causes severe yield losses of soybean worldwide. In the present study, a representative population of 185 soybean accessions was selected and utilized to identify the quantitative trait nucleotide (QTN) of partial resistance to soybean SSR via a genome-wide association study (GWAS). A total of 22,048 single-nucleotide polymorphisms (SNPs) with minor allele frequencies (MAF) > 5% and missing data < 3% were used to assess linkage disequilibrium (LD) levels. Association signals associated with SSR partial resistance were identified by two models, including compressed mixed linear model (CMLM) and multi-locus random-SNP-effect mixed linear model (mrMLM). Finally, seven QTNs with major effects (a known locus and six novel loci) via CMLM and nine novel QTNs with minor effects via mrMLM were detected in relation to partial resistance to SSR, respectively. One of all the novel loci (Gm05:14834789 on Chr.05), which was co-located by these two methods, might be a stable one that showed high significance in SSR partial resistance. Additionally, a total of 71 major and 85 minor candidate genes located in the 200-kb genomic region of each peak SNP detected by CMLM and mrMLM were found, respectively. By using a gene-based association, a total of six SNPs from three major effects genes and eight SNPs from four minor effects genes were identified. Of them, Glyma.18G012200 has been characterized as a significant element in controlling fungal disease in plants.


Assuntos
Ascomicetos/patogenicidade , Resistência à Doença/genética , Estudo de Associação Genômica Ampla , Caules de Planta/imunologia , Soja/imunologia , Desequilíbrio de Ligação , Micoses , Caules de Planta/genética , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Soja/genética
8.
PLoS One ; 15(5): e0232448, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32433708

RESUMO

Several Botryosphaeriaceae species are known to occur worldwide, causing dieback, canker and fruit rot on various hosts. Surveys conducted in ten commercial citrus orchards in the northern region of Algeria revealed five species of Botryosphaeriaceae belonging to three genera associated with diseased trees. Morphological and cultural characteristics as well as phylogenetic analyses of the internal transcribed spacer (ITS) region and the translation elongation factor 1-alpha (tef1-α) identified Diplodia mutila, Diplodia seriata, Dothiorella viticola, Lasiodiplodia mediterranea and a novel species which is here described as Lasiodiplodia mithidjana sp. nov.. Of these, L. mithidjana (14.1% of the samples) and L. mediterranea (13% of the samples) were the most widespread and abundant species. Pathogenicity tests revealed that L. mediterranea and D. seriata were the most aggressive species on citrus shoots. This study highlights the importance of Botryosphaeriaceae species as agents of canker and dieback of citrus trees in Algeria.


Assuntos
Ascomicetos/patogenicidade , Citrus sinensis/microbiologia , Doenças das Plantas/microbiologia , Argélia , Ascomicetos/classificação , Ascomicetos/genética , DNA Fúngico/genética , Filogenia , Especificidade da Espécie , Virulência
9.
PLoS One ; 15(5): e0229630, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401759

RESUMO

Chromoblastomycosis (CBM) is a chronic subcutaneous mycosis caused by traumatic implantation of many species of black fungi. Due to the refractoriness of some cases and common recurrence of CBM, a more effective and less time-consuming treatment is mandatory. The aim of this study was to identify compounds with in vitro antifungal activity in the Pathogen Box® compound collection against different CBM agents. Synergism of these compounds with drugs currently used to treat CBM was also assessed. An initial screening of the drugs present in this collection at 1 µM was performed with a Fonsecaea pedrosoi clinical strain according to the EUCAST protocol. The compounds with activity against this fungus were also tested against other seven etiologic agents of CBM (Cladophialophora carrionii, Phialophora verrucosa, Exophiala jeanselmei, Exophiala dermatitidis, Fonsecaea monophora, Fonsecaea nubica, and Rhinocladiella similis) at concentrations ranging from 0.039 to 10 µM. The analysis of potential synergism of these compounds with itraconazole and terbinafine was performed by the checkerboard method. Eight compounds inhibited more than 60% of the F. pedrosoi growth: difenoconazole, bitertanol, iodoquinol, azoxystrobin, MMV688179, MMV021013, trifloxystrobin, and auranofin. Iodoquinol produced the lowest MIC values (1.25-2.5 µM) and MMV688179 showed MICs that were higher than all compounds tested (5 - >10 µM). When auranofin and itraconazole were tested in combination, a synergistic interaction (FICI = 0.37) was observed against the C. carrionii isolate. Toxicity analysis revealed that MMV021013 showed high selectivity indices (SI ≥ 10) against the fungi tested. In summary, auranofin, iodoquinol, and MMV021013 were identified as promising compounds to be tested in CBM models of infection.


Assuntos
Antifúngicos/farmacologia , Cromoblastomicose/tratamento farmacológico , Sinergismo Farmacológico , Fungos/patogenicidade , Acetatos/farmacologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/patogenicidade , Auranofina/farmacologia , Compostos de Bifenilo/farmacologia , Cromoblastomicose/microbiologia , Cromoblastomicose/patologia , Dioxolanos/farmacologia , Exophiala/efeitos dos fármacos , Exophiala/patogenicidade , Fungos/efeitos dos fármacos , Humanos , Iminas/farmacologia , Iodoquinol/farmacologia , Pirimidinas/farmacologia , Estrobilurinas/farmacologia , Triazóis/farmacologia
10.
PLoS One ; 15(5): e0227396, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469865

RESUMO

Elsinoë fawcettii, a necrotrophic fungal pathogen, causes citrus scab on numerous citrus varieties around the world. Known pathotypes of E. fawcettii are based on host range; additionally, cryptic pathotypes have been reported and more novel pathotypes are thought to exist. E. fawcettii produces elsinochrome, a non-host selective toxin which contributes to virulence. However, the mechanisms involved in potential pathogen-host interactions occurring prior to the production of elsinochrome are unknown, yet the host-specificity observed among pathotypes suggests a reliance upon such mechanisms. In this study we have generated a whole genome sequencing project for E. fawcettii, producing an annotated draft assembly 26.01 Mb in size, with 10,080 predicted gene models and low (0.37%) coverage of transposable elements. A small proportion of the assembly showed evidence of AT-rich regions, potentially indicating genomic regions with increased plasticity. Using a variety of computational tools, we mined the E. fawcettii genome for potential virulence genes as candidates for future investigation. A total of 1,280 secreted proteins and 276 candidate effectors were predicted and compared to those of other necrotrophic (Botrytis cinerea, Parastagonospora nodorum, Pyrenophora tritici-repentis, Sclerotinia sclerotiorum and Zymoseptoria tritici), hemibiotrophic (Leptosphaeria maculans, Magnaporthe oryzae, Rhynchosporium commune and Verticillium dahliae) and biotrophic (Ustilago maydis) plant pathogens. Genomic and proteomic features of known fungal effectors were analysed and used to guide the prioritisation of 120 candidate effectors of E. fawcettii. Additionally, 378 carbohydrate-active enzymes were predicted and analysed for likely secretion and sequence similarity with known virulence genes. Furthermore, secondary metabolite prediction indicated nine additional genes potentially involved in the elsinochrome biosynthesis gene cluster than previously described. A further 21 secondary metabolite clusters were predicted, some with similarity to known toxin producing gene clusters. The candidate virulence genes predicted in this study provide a comprehensive resource for future experimental investigation into the pathogenesis of E. fawcettii.


Assuntos
Ascomicetos/genética , Citrus/microbiologia , Genoma Fúngico/genética , Anotação de Sequência Molecular , Ascomicetos/patogenicidade , Parede Celular/enzimologia , Mineração de Dados , Família Multigênica/genética , Metabolismo Secundário/genética
11.
Mol Plant Microbe Interact ; 33(8): 1022-1024, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32364420

RESUMO

The genus Stagonosporopsis is classified within the Didymellaceae family and has around 40 associated species. Among them, several species are important plant pathogens responsible for significant losses in economically important crops worldwide. Stagonosporopsis vannaccii is a newly described species pathogenic to soybean. Here, we present the draft whole-genome sequence, gene prediction, and annotation of S. vannaccii isolate LFN0148 (also known as IMI 507030). To our knowledge, this is the first genome sequenced of this species and represents a new useful source for future research on fungal comparative genomics studies.


Assuntos
Ascomicetos , Genoma Fúngico , Doenças das Plantas/microbiologia , Soja/microbiologia , Ascomicetos/genética , Ascomicetos/patogenicidade , Genômica , Anotação de Sequência Molecular
12.
Mol Plant Microbe Interact ; 33(8): 1008-1021, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32370643

RESUMO

Powdery mildews are obligate biotrophic fungal pathogens causing important diseases of plants worldwide. Very little is known about the requirements for their pathogenicity at the molecular level. This is largely due to the inability to culture these organisms in vitro or to modify them genetically. Here, we describe a mutagenesis procedure based on ultraviolet (UV) irradiation to accumulate mutations in the haploid genome of the barley powdery mildew pathogen Blumeria graminis f. sp. hordei. Exposure of B. graminis f. sp. hordei conidia to different durations of UV-C radiation (10 s to 12 min) resulted in a reduced number of macroscopically visible fungal colonies. B. graminis f. sp. hordei colony number was negatively correlated with exposure time and the total number of consecutive cycles of UV irradiation. Dark incubation following UV exposure further reduced fungal viability, implying that photoreactivation is an important component of DNA repair in B. graminis f. sp. hordei. After several rounds of UV mutagenesis, we selected two mutant isolates in addition to the parental B. graminis f. sp. hordei K1 isolate for whole-genome resequencing. By combining automated prediction of sequence variants and their manual validation, we identified unique UV-induced mutations in the genomes of the two isolates. Most of these mutations were in the up- or downstream regions of genes or in the intergenic space. Some of the variants detected in genes led to predicted missense mutations. As an additional insight, our bioinformatic analyses revealed a complex population structure within supposedly clonal B. graminis f. sp. hordei isolates.


Assuntos
Ascomicetos , Genoma Fúngico/efeitos da radiação , Mutagênese , Doenças das Plantas/microbiologia , Ascomicetos/genética , Ascomicetos/patogenicidade , Ascomicetos/efeitos da radiação , Sequenciamento de Nucleotídeos em Larga Escala , Hordeum/microbiologia , Análise de Sequência de DNA , Raios Ultravioleta
13.
Mol Plant Microbe Interact ; 33(8): 1080-1090, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32392451

RESUMO

Marssonina brunnea, the causative pathogen of Marssonina leaf spot of poplars (MLSP), devastates poplar plantations by forming black spots on leaves and defoliating trees. Although MLSP has been studied for over 30 years, the key genes that function during M. brunnea infection and their effects on plant growth are poorly understood. Here, we used multigene association studies to investigate the effects of key genes in the plant-pathogen interaction pathway, as revealed by transcriptome analysis, on photosynthesis and growth in a natural population of 435 Populus tomentosa individuals. By analyzing transcriptomic changes during three stages of infection, we detected 628 transcription factor genes among the 7,611 differentially expressed genes that might be associated with basal defense responses. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that transcriptomic changes across different stages of infection lead to the reprogramming of metabolic processes possibly related to defense activation. We identified 29,399 common single-nucleotide polymorphisms (SNPs) within 221 full-length genes in plant-pathogen interaction pathways that were significantly associated with photosynthetic and growth traits. We also detected 4,460 significant epistatic pairs associated with stomatal conductance, tree diameter, and tree height. Epistasis analysis uncovered significant interactions between 2,561 SNP-SNP pairs from different functional modules in the plant-pathogen interaction pathway, revealing possible genetic interactions. This analysis revealed many key genes that function during M. brunnea infection and their potential roles in mediating photosynthesis and plant growth, shedding light on genetic interactions between functional modules in the plant-pathogen interaction pathway.


Assuntos
Ascomicetos , Genes de Plantas , Doenças das Plantas/genética , Populus , Ascomicetos/genética , Ascomicetos/patogenicidade , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Polimorfismo de Nucleotídeo Único , Populus/genética , Populus/microbiologia
14.
PLoS Comput Biol ; 16(3): e1007703, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32231370

RESUMO

Spatial analyses of pathogen occurrence in their natural surroundings entail unique opportunities for assessing in vivo drivers of disease epidemiology. Such studies are however confronted by the complexity of the landscape driving epidemic spread and disease persistence. Since relevant information on how the landscape influences epidemiological dynamics is rarely available, simple spatial models of spread are often used. In the current study we demonstrate both how more complex transmission pathways could be incorpoted to epidemiological analyses and how this can offer novel insights into understanding disease spread across the landscape. Our study is focused on Podosphaera plantaginis, a powdery mildew pathogen that transmits from one host plant to another by wind-dispersed spores. Its host populations often reside next to roads and thus we hypothesize that the road network influences the epidemiology of P. plantaginis. To analyse the impact of roads on the transmission dynamics, we consider a spatial dataset on the presence-absence records on the pathogen collected from a fragmented landscape of host populations. Using both mechanistic transmission modeling and statistical modeling with road-network summary statistics as predictors, we conclude the evident role of the road network in the progression of the epidemics: a phenomena which is manifested both in the enhanced transmission along the roads and in infections typically occurring at the central hub locations of the road network. We also demonstrate how the road network affects the spread of the pathogen using simulations. Jointly our results highlight how human alteration of natural landscapes may increase disease spread.


Assuntos
Ascomicetos/patogenicidade , Microbiologia Ambiental , Modelos Biológicos , Modelos Estatísticos , Doenças das Plantas , Biologia Computacional , Sistemas de Informação Geográfica , Doenças das Plantas/microbiologia , Doenças das Plantas/estatística & dados numéricos , Transportes
15.
Nat Commun ; 11(1): 1910, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313046

RESUMO

Yield losses caused by fungal pathogens represent a major threat to global food production. One of the most devastating fungal wheat pathogens is Zymoseptoria tritici. Despite the importance of this fungus, the underlying mechanisms of plant-pathogen interactions are poorly understood. Here we present a conceptual framework based on coinfection assays, comparative metabolomics, and microbiome profiling to study the interaction of Z. tritici in susceptible and resistant wheat. We demonstrate that Z. tritici suppresses the production of immune-related metabolites in a susceptible cultivar. Remarkably, this fungus-induced immune suppression spreads within the leaf and even to other leaves, a phenomenon that we term "systemic induced susceptibility". Using a comparative metabolomics approach, we identify defense-related biosynthetic pathways that are suppressed and induced in susceptible and resistant cultivars, respectively. We show that these fungus-induced changes correlate with changes in the wheat leaf microbiome. Our findings suggest that immune suppression by this hemibiotrophic pathogen impacts specialized plant metabolism, alters its associated microbial communities, and renders wheat vulnerable to further infections.


Assuntos
Ascomicetos/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Interações Hospedeiro-Patógeno/fisiologia , Metaboloma , Microbiota/fisiologia , Imunidade Vegetal/fisiologia , Ascomicetos/patogenicidade , Benzoxazinas/metabolismo , Vias Biossintéticas , Coinfecção , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Metabolismo Secundário , Triticum/imunologia , Triticum/microbiologia
16.
Mol Plant Microbe Interact ; 33(7): 902-910, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32282260

RESUMO

Clonostachys chloroleuca is a mycoparasite used for biocontrol of numerous fungal plant pathogens. Sequencing of the transcriptome of C. chloroleuca following mycoparasitization of the sclerotia of Sclerotinia sclerotiorum revealed significant upregulation of a mitogen-activated protein kinase (MAPK)-encoding gene, crmapk. Although MAPKs are known to regulate fungal growth and development, the function of crmapk in C. chloroleuca mycoparasitism is unclear. In this study, we investigated the role of crmapk in C. chloroleuca mycoparasitism through gene knockout and complementation. Deletion of crmapk had no influence on the C. chloroleuca morphological characteristics but could significantly reduce the mycoparasitic ability to sclerotia and biocontrol capacity to soybean Sclerotinia stem rot; crmapk complementation restored these abilities. Transcriptome analysis between Δcrmapk and the wild-type strain revealed numerous genes were significantly down-regulated after crmapk deletion, including cytochrome P450, transporters, and cell wall-degrading enzymes (CWDEs). Our findings indicate that crmapk influences C. chloroleuca mycoparasitism by regulation of genes controlling the activity of CWDEs or antibiotic production. This study provides a basis for further studies of the molecular mechanism of C. chloroleuca mycoparasitism.


Assuntos
Ascomicetos/patogenicidade , Agentes de Controle Biológico , Hypocreales/fisiologia , Proteínas Quinases Ativadas por Mitógeno/genética , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Genes Fúngicos , Teste de Complementação Genética , Hypocreales/genética , Doenças das Plantas/microbiologia , Soja/microbiologia
17.
Mol Plant Microbe Interact ; 33(7): 880-883, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32310704

RESUMO

The fungus Myriosclerotinia sulcatula is a close relative of the notorious polyphagous plant pathogens Botrytis cinerea and Sclerotinia sclerotiorum but exhibits a host range restricted to plants from the Carex genus (Cyperaceae family). To date, there are no genomic resources available for fungi in the Myriosclerotinia genus. Here, we present a chromosome-scale reference genome assembly for M. sulcatula. The assembly contains 24 contigs with a total length of 43.53 Mbp, with scaffold N50 of 2,649.7 kbp and N90 of 1,133.1 kbp. BRAKER-predicted gene models were manually curated using WebApollo, resulting in 11,275 protein-coding genes that we functionally annotated. We provide a high-quality reference genome assembly and annotation for M. sulcatula as a resource for studying evolution and pathogenicity in fungi from the Sclerotiniaceae family.


Assuntos
Ascomicetos , Carex (Planta)/microbiologia , Genoma Fúngico , Doenças das Plantas/microbiologia , Ascomicetos/genética , Ascomicetos/patogenicidade , Cromossomos Fúngicos/genética
18.
Mol Plant Microbe Interact ; 33(7): 982-995, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32223579

RESUMO

The family Sclerotiniaceae includes important phytopathogens, such as Botrytis cinerea and Sclerotinia sclerotiorum, that activate plant immune responses to facilitate infection propagation. The mechanisms of plant resistance to these necrotrophic pathogens are still poorly understood. To discover mechanisms of resistance, we used the Ciborinia camelliae (Sclerotiniaceae)-Camellia spp. pathosystem. This fungus induces rapid infection of the blooms of susceptible cultivar Nicky Crisp (Camellia japonica × Camellia pitardii var. pitardii), while Camellia lutchuensis is highly resistant. Genome-wide analysis of gene expression in resistant plants revealed fast modulation of host transcriptional activity 6 h after ascospore inoculation. Ascospores induced the same defense pathways in the susceptible Camellia cultivar but much delayed and coinciding with disease development. We next tested the hypothesis that differences in defense timing influences disease outcome. We induced early defense in the susceptible cultivar using methyl jasmonate and this strongly reduced disease development. Conversely, delaying the response in the resistant species, by infecting it with actively growing fungal mycelium, increased susceptibility. The same plant defense pathways, therefore, contribute to both resistance and susceptibility, suggesting that defense timing is a critical factor in plant health, and resistance against necrotrophic pathogens may occur during the initial biotrophy-like stages.


Assuntos
Ascomicetos/patogenicidade , Camellia/genética , Resistência à Doença/genética , Flores/microbiologia , Doenças das Plantas/genética , Imunidade Vegetal , Acetatos , Camellia/microbiologia , Ciclopentanos , Regulação da Expressão Gênica de Plantas , Oxilipinas , Doenças das Plantas/microbiologia , Fatores de Tempo
19.
Mol Plant Microbe Interact ; 33(7): 884-887, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32233960

RESUMO

Phyllachora maydis is an important fungal pathogen that causes tar spot of corn and has led to significant yield loss in the United States and other countries. P. maydis is an obligate biotroph belonging to the Sordariomycetes class of Ascomycota. Due to the challenges posed by their obligate nature, there is no genome sequence available in the Phyllachora genus. P. maydis isolate PM01 was collected from a corn field in Indiana and the genome was determined by next-generation sequencing. The assembly size is 45.7 Mb, with 56.46% repetitive sequences. There are 5,992 protein-coding genes and 59 are predicted as effector proteins. This genome resource will increase our understanding of genomic features of P. maydis and will assist in studying the corn-P. maydis interaction and identifying potential resistant candidates for corn breeding programs.


Assuntos
Ascomicetos , Genoma Fúngico , Doenças das Plantas/microbiologia , Zea mays/microbiologia , Ascomicetos/genética , Ascomicetos/patogenicidade , Sequências Repetitivas de Ácido Nucleico , Estados Unidos
20.
Proc Natl Acad Sci U S A ; 117(13): 7255-7262, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32179668

RESUMO

Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate disease impacts by fueling sustained transmission, seasonal epidemics, and repeated spillover events. While theory suggests that the presence of an environmental reservoir increases the risk of host declines and threat of extinction, the influence of reservoir dynamics on transmission and population impacts remains poorly described. Here we show that the extent of the environmental reservoir explains broad patterns of host infection and the severity of disease impacts of a virulent pathogen. We examined reservoir and host infection dynamics and the resulting impacts of Pseudogymnoascus destructans, the fungal pathogen that causes white-nose syndrome, in 39 species of bats at 101 sites across the globe. Lower levels of pathogen in the environment consistently corresponded to delayed infection of hosts, fewer and less severe infections, and reduced population impacts. In contrast, an extensive and persistent environmental reservoir led to early and widespread infections and severe population declines. These results suggest that continental differences in the persistence or decay of P. destructans in the environment altered infection patterns in bats and influenced whether host populations were stable or experienced severe declines from this disease. Quantifying the impact of the environmental reservoir on disease dynamics can provide specific targets for reducing pathogen levels in the environment to prevent or control future epidemics.


Assuntos
Quirópteros/microbiologia , Reservatórios de Doenças/microbiologia , Micoses/epidemiologia , Animais , Ascomicetos/patogenicidade , Epidemias , Hibernação , Micoses/microbiologia , Nariz/microbiologia , Doenças Nasais/epidemiologia , Doenças Nasais/microbiologia , Dinâmica Populacional , Estações do Ano
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