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1.
Plant Dis ; 104(11): 2898-2904, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33006915

RESUMO

Asparagus stem blight is a regional disease. In the present study, we compared strains of Phomopsis asparagi from six different provinces to determine their biological characteristics and genetic diversity, differences in the pycnidium and conidium production, pathogenicity, and growth rate. Considerable differences were established in the pycnidium and conidium production among the P. asparagi strains from the six studied provinces. The largest pycnidium and conidium production had the strains from Fujian, followed by those from Hainan. The virulence of P. asparagi strains was significantly different but without a correlation with the geographical source of the strain. FJ2 had the highest virulence, followed by HN2, SD4, and SD5, whereas SD5 had the lowest virulence. The colony diameter and dry weight of the strains of asparagus stem blight fungus from the six provinces were substantially different. The colonies of HN1-5 had the largest diameters, whereas those of XT1-5, LT1-3, FJ1-5, and SX6 had smaller diameters. Four primers with good repeatability and strong specificity were selected from 100 intersimple sequence repeat (ISSR) primers. ISSR-PCR amplification was performed on 36 strains of asparagus stem blight fungus, and a large number of repeatable DNA fingerprints were obtained. Most of the amplified fragments were within 300 to 500 bp. In all, 69 total points, 64 multiple points, and 92.75% polymorphism points were established. The number of ISSR gene sites detected by four primers ranged from 14 to 20, with an average of 16 multiple sites. The copolymerization was divided into three groups: XT1-5, LT1-3, and FJ1-5, which were clustered into the first group; SD1-6, SX1-6, and HB1-6, clustered into the second group; and HN1-5 in the third group. The results of the cluster analysis revealed that the strains of the neighboring provinces had a nearer phylogenetic relationship than that between distant ones. Therefore, the system evolution of P. asparagi is related to the geographical distribution of its strains.


Assuntos
Ascomicetos , Asparagus (Planta) , Fungos Mitospóricos , Ascomicetos/genética , Variação Genética , Filogenia
2.
Proc Natl Acad Sci U S A ; 117(39): 24243-24250, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32929037

RESUMO

The necrotrophic fungal pathogen Cochliobolus victoriae produces victorin, a host-selective toxin (HST) essential for pathogenicity to certain oat cultivars with resistance against crown rust. Victorin is a mixture of highly modified heterodetic cyclic hexapeptides, previously assumed to be synthesized by a nonribosomal peptide synthetase. Herein, we demonstrate that victorin is a member of the ribosomally synthesized and posttranslationally modified peptide (RiPP) family of natural products. Analysis of a newly generated long-read assembly of the C. victoriae genome revealed three copies of precursor peptide genes (vicA1-3) with variable numbers of "GLKLAF" core peptide repeats corresponding to the victorin peptide backbone. vicA1-3 are located in repeat-rich gene-sparse regions of the genome and are loosely clustered with putative victorin biosynthetic genes, which are supported by the discovery of compact gene clusters harboring corresponding homologs in two distantly related plant-associated Sordariomycete fungi. Deletion of at least one copy of vicA resulted in strongly diminished victorin production. Deletion of a gene encoding a DUF3328 protein (VicYb) abolished the production altogether, supporting its predicted role in oxidative cyclization of the core peptide. In addition, we uncovered a copper amine oxidase (CAO) encoded by vicK, in which its deletion led to the accumulation of new glycine-containing victorin derivatives. The role of VicK in oxidative deamination of the N-terminal glycyl moiety of the hexapeptides to the active glyoxylate forms was confirmed in vitro. This study finally unraveled the genetic and molecular bases for biosynthesis of one of the first discovered HSTs and expanded our understanding of underexplored fungal RiPPs.


Assuntos
Ascomicetos/metabolismo , Proteínas Fúngicas/metabolismo , Micotoxinas/metabolismo , Ascomicetos/genética , Desaminação , Proteínas Fúngicas/genética , Proteínas Fúngicas/toxicidade , Deleção de Genes , Família Multigênica , Micotoxinas/genética , Micotoxinas/toxicidade , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional
3.
Proc Natl Acad Sci U S A ; 117(35): 21495-21503, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32796103

RESUMO

Symbioses are evolutionarily pervasive and play fundamental roles in structuring ecosystems, yet our understanding of their macroevolutionary origins, persistence, and consequences is incomplete. We traced the macroevolutionary history of symbiotic and phenotypic diversification in an iconic symbiosis, lichens. By inferring the most comprehensive time-scaled phylogeny of lichen-forming fungi (LFF) to date (over 3,300 species), we identified shifts among symbiont classes that broadly coincided with the convergent evolution of phylogenetically or functionally similar associations in diverse lineages (plants, fungi, bacteria). While a relatively recent loss of lichenization in Lecanoromycetes was previously identified, our work instead suggests lichenization was abandoned far earlier, interrupting what had previously been considered a direct switch between trebouxiophycean and trentepohlialean algal symbionts. Consequently, some of the most diverse clades of LFF are instead derived from nonlichenized ancestors and re-evolved lichenization with Trentepohliales algae, a clade that also facilitated lichenization in unrelated lineages of LFF. Furthermore, while symbiont identity and symbiotic phenotype influence the ecology and physiology of lichens, they are not correlated with rates of lineage birth and death, suggesting more complex dynamics underly lichen diversification. Finally, diversification patterns of LFF differed from those of wood-rotting and ectomycorrhizal taxa, likely reflecting contrasts in their fundamental biological properties. Together, our work provides a timeline for the ecological contributions of lichens, and reshapes our understanding of symbiotic persistence in a classic model of symbiosis.


Assuntos
Líquens/genética , Líquens/metabolismo , Simbiose/genética , Ascomicetos/genética , Evolução Biológica , Clorófitas/genética , Ecossistema , Filogenia , Análise de Sequência de DNA/métodos
4.
Plant Dis ; 104(11): 3002-3009, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32822262

RESUMO

Precise diagnosis of plant diseases is one of the most effective tools to minimize yield losses. Colletotrichum truncatum, Corynespora cassiicola, and Sclerotinia sclerotiorum are common soilborne pathogens that affect soybeans all over the world. We developed a multiplex quantitative real-time polymerase chain reaction (qPCR) assay to simultaneously detect and quantify the three pathogens in soybean seeds and to survey their occurrence in the main soybean production areas in Brazil. Species-specific primers and probes for C. truncatum and C. cassiicola were designed based on GAPDH and TEF1 genes, respectively, to be combined with qPCR detection of S. sclerotiorum previously reported. The multiplex qPCR assay was successful in the simultaneous detection of C. truncatum, C. cassiicola, and S. sclerotiorum, along with a host internal control. The four pathogens were detected and quantified in artificially and naturally infested soybean seeds, even in the lowest incidence level tested of 0.0625% or 1 infected seed out of 1,599 healthy ones. From 81 seed samples tested, C. truncatum was the most frequently detected pathogen and with higher incidence levels (0.25 to 0.125%), followed by S. sclerotiorum and C. cassiicola, both with lower incidence levels (0.125 to 0.0625%). Together, the results evidenced the high sensitivity of the multiplex qPCR assay, indicating its usefulness for a quick and reliable diagnosis of soybean diseases in seeds.


Assuntos
Ascomicetos , Colletotrichum , Ascomicetos/genética , Brasil , Colletotrichum/genética , Reação em Cadeia da Polimerase em Tempo Real , Sementes , Soja/genética
5.
Plant Dis ; 104(10): 2551-2555, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32804013

RESUMO

Ormosia pinnata (Lour.) Merr. is an important tree used for landscape and plant recovery of barren slopes in China. During an investigation of plant disease on landscape trees in 2018, a dieback was observed on O. pinnata trees in Guangzhou, Guangdong Province, China. Symptoms were characterized by initial dryness of the twigs and eventual death of the whole branch of the tree. Isolations from symptomatic branches yielded 13 isolates including two main morphotypes. Pathogenicity tests showed that isolate GDOP1 from Type I caused dieback of O. pinnata. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA (ITS1-5.8S-ITS2) and partial sequence of the translation elongation factor 1α (EF1-α), the fungus causing dieback on O. pinnata was identified as Lasiodiplodia pseudotheobromae. This is the first report of L. pseudotheobromae infecting O. pinnata in the world.


Assuntos
Ascomicetos/genética , China , DNA Fúngico/genética , Filogenia , Doenças das Plantas
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.
Appl Environ Microbiol ; 86(17)2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32631859

RESUMO

Understanding how fungicide application practices affect selection for fungicide resistance is imperative for continued sustainable agriculture. Here, we examined the effect of field applications of the succinate dehydrogenase inhibitor (SDHI) fluxapyroxad at different doses and mixtures on the SDHI sensitivity of Venturia inaequalis, the apple scab pathogen. Fungicide applications were part of selection programs involving different doses (high or low) and mixtures (with a second single-site fungicide or a multisite fungicide). These programs were tested in two apple orchards over 4 years to determine potential cumulative selection effects on resistance. Each year after program applications, apple scab lesions were collected, and relative growth assays were conducted to understand shifts in fluxapyroxad sensitivity. After 4 years, there was a trend toward a reduction in sensitivity to fluxapyroxad for most selection programs in comparison to that in the non-selective-pressure control. In most years, the selection program plots treated with low-dose fluxapyroxad applications resulted in a larger number of isolates with reduced sensitivity, supporting the use of higher doses for disease management. Few significant differences (P < 0.05) in fungicide sensitivity were observed between isolates collected from plots where fungicide mixtures were applied compared to that in untreated plots, supporting the use of multiple modes of action in field applications. In all, appropriate doses and mixtures may contribute to increased longevity of SDHI fungicides used on perennial crops like apples.IMPORTANCE Of much debate is the effect of fungicide application dose on resistance development, as fungicide resistance is a critical barrier to effective disease management in agricultural systems. Our field study in apples investigated the effect of fungicide application dose and mixture on the selection of succinate dehydrogenase inhibitor resistance in Venturia inaequalis, a fungal pathogen that causes the economically important disease apple scab. Understanding how to best delay the development of resistance can result in increased efficacy, fewer applications, and sustainable fungicide use. Results from this study may have relevance to other perennial crops that require multiple fungicide applications and that are impacted by the development of resistance.


Assuntos
Amidas/farmacologia , Ascomicetos/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Proteínas Fúngicas/antagonistas & inibidores , Fungicidas Industriais/farmacologia , Succinato Desidrogenase/antagonistas & inibidores , Ascomicetos/genética , Ascomicetos/fisiologia , Relação Dose-Resposta a Droga , Farmacorresistência Fúngica/genética
8.
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
9.
PLoS One ; 15(7): e0218636, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32639969

RESUMO

Microbial colonization of bone is an important mechanism of postmortem skeletal degradation. However, the types and distributions of bone and tooth colonizing microbes are not well characterized. It is unknown if microbial communities vary in abundance or composition between bone element types, which could help explain differences in human DNA preservation. The goals of the present study were to (1) identify the types of microbes capable of colonizing different human bone types and (2) relate microbial abundances, diversity, and community composition to bone type and human DNA preservation. DNA extracts from 165 bone and tooth samples from three skeletonized individuals were assessed for bacterial loading and microbial community composition and structure. Random forest models were applied to predict operational taxonomic units (OTUs) associated with human DNA concentration. Dominant bacterial bone colonizers were from the phyla Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, and Planctomycetes. Eukaryotic bone colonizers were from Ascomycota, Apicomplexa, Annelida, Basidiomycota, and Ciliophora. Bacterial loading was not a significant predictor of human DNA concentration in two out of three individuals. Random forest models were minimally successful in identifying microbes related to human DNA concentration, which were complicated by high variability in community structure between individuals and body regions. This work expands on our understanding of the types of microbes capable of colonizing the postmortem human skeleton and potentially contributing to human skeletal DNA degradation.


Assuntos
Osso e Ossos/microbiologia , Microbiota , Antropologia , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Autopsia , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , DNA/química , DNA/metabolismo , Humanos , Masculino , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Dente/microbiologia
10.
PLoS One ; 15(7): e0236165, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32697804

RESUMO

In order to define the diversity and composition of the microbial communities colonizing of the soil microbiome of the Jinsha earthen relic, we used high-throughput sequencing technology to identify and characterize the microbiota in 22 samples collected from the Jinsha earthen relic in China during 2017 and 2018. We compared the taxonomy of the microbial communities from samples taken at different times and different sites. Our results showed that the identity of the dominant bacterial phyla differed among the samples. Proteobacteria (23-86.2%) were the predominant bacterial phylum in all samples taken from site A in both 2017 and 2018. However, Actinobacteria (21-92.3%) were the most popular bacterial phylum in samples from sites B and C in 2017 and 2018. Ascomycota were identified as the only fungal phyla in samples in 2017. However, the group varied drastically in relative abundance between 2017 and 2018. Functional analysis of the soil bacterial community suggested that abundant members of the microbiota may be associated with metabolism and the specific environment. This report was the first high-throughput sequencing study of the soil of the Jinsha earthen relic microbiome. Since soil microbiota can damage soil and archeological structures, comprehensive analyses of the microbiomes at archeological sites may contribute to the understand of the influence of microorganisms on the degradation of soil, as well as to the identification of potentially beneficial or undesirable members of these microbial communities in archeological sites. The study will be helpful to provide effective data and guidance for the prevention and control of microbial corrosion of the Jinsha earthen relic.


Assuntos
Arqueologia , Microbiota/genética , Microbiologia do Solo , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Ascomicetos/genética , Ascomicetos/isolamento & purificação , China , DNA Bacteriano/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética
11.
PLoS One ; 15(7): e0236429, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730288

RESUMO

The soilborne fungus Gaeumannomyces tritici (G. tritici) causes the take-all disease on wheat roots. Ambient pH has been shown to be critical in different steps of G. tritici life cycle such as survival in bulk soil, saprophytic growth, and pathogenicity on plants. There are however intra-specific variations and we previously found two types of G. tritici strains that grow preferentially either at acidic pH or at neutral/alkaline pH; gene expression involved in pH-signal transduction pathway and pathogenesis was differentially regulated in two strains representative of these types. To go deeper in the description of the genetic pathways and the understanding of this adaptative mechanism, transcriptome sequencing was achieved on two strains (PG6 and PG38) which displayed opposite growth profiles in two pH conditions (acidic and neutral). PG6, growing better at acidic pH, overexpressed in this condition genes related to cell proliferation. In contrast, PG38, which grew better at neutral pH, overexpressed in this condition genes involved in fatty acids and amino acid metabolisms, and genes potentially related to pathogenesis. This strain also expressed stress resistance mechanisms at both pH, to assert a convenient growth under various ambient pH conditions. These differences in metabolic pathway expression between strains at different pH might buffer the effect of field or soil variation in wheat fields, and explain the success of the pathogen.


Assuntos
Ascomicetos/genética , Transcriptoma/genética , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/isolamento & purificação , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Ontologia Genética , Genes Fúngicos , Concentração de Íons de Hidrogênio , Micélio/crescimento & desenvolvimento , Especificidade da Espécie , Triticum
12.
Mol Plant Microbe Interact ; 33(9): 1116-1128, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32484383

RESUMO

Pectin, as part of the fruit cell wall, can be degraded by brown rot fungi by coordinating the production, secretion, and action of extracellular enzymes. In this study, pectin utilization by the necrotroph Monilinia laxa 8L was studied by in vitro and in silico approaches. A total of 403 genes encoding carbohydrate-active enzymes (CAZymes) were identified, including 38 coding a predicted pectin-degrading activity. Analyzing the differences between M. laxa 8L exoproteomes in media containing glucose and pectin as sole carbon sources, we identified 107 pectin-specific proteins, among them, 64.48% harbor a classical secretory activity, including 42 CAZymes and six pectin-degrading proteins. Analyzing the gene-expression patterns of some pectinase families revealed their possible sequential action in pectin disassembly. We found, in vitro, an early pectin-dependent induction of MlRGAE1, MlPG1, and three members of the rhamnosidase family (MlαRHA2, MlαRHA3, and MlαRHA6) and late response of MlPG2 and MlPNL3. M. laxa 8L has the ability to use both pectin and byproducts as carbon sources, based on a functional pectinolytic machinery encoded in its genome, subjected to pectin-dependent regulation and appropriate secretion mechanisms of these pectinolytic enzymes. Differences in the secretion and transcription profile of M. laxa 8L provided insights into the different mechanisms that contribute to brown rot development.


Assuntos
Ascomicetos , Carbono/metabolismo , Genes Fúngicos , Pectinas/metabolismo , Ascomicetos/enzimologia , Ascomicetos/genética , Parede Celular , Poligalacturonase/genética , Proteoma , Transcriptoma
13.
Mol Plant Microbe Interact ; 33(9): 1098-1099, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32552350

RESUMO

Paraphaeosphaeria genus includes plant pathogens or biocontrol agents as well as bioremediators and endophytic fungi. Paraphaeosphaeria sporulosa 10515 was isolated in 2013 as an endophyte of Festuca spp. collected on Mount Etna at 1,832 meters above sea level. Here, we present the first-draft whole-genome sequence of a P. sporulosa endophytic isolate. This data will be useful for future research on understanding the genetic bases of endophytism.


Assuntos
Ascomicetos , Festuca/microbiologia , Genoma Fúngico , Ascomicetos/genética , Endófitos/genética , Itália
14.
PLoS Pathog ; 16(6): e1008652, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32574207

RESUMO

Plants trigger immune responses upon recognition of fungal cell wall chitin, followed by the release of various antimicrobials, including chitinase enzymes that hydrolyze chitin. In turn, many fungal pathogens secrete LysM effectors that prevent chitin recognition by the host through scavenging of chitin oligomers. We previously showed that intrachain LysM dimerization of the Cladosporium fulvum effector Ecp6 confers an ultrahigh-affinity binding groove that competitively sequesters chitin oligomers from host immune receptors. Additionally, particular LysM effectors are found to protect fungal hyphae against chitinase hydrolysis during host colonization. However, the molecular basis for the protection of fungal cell walls against hydrolysis remained unclear. Here, we determined a crystal structure of the single LysM domain-containing effector Mg1LysM of the wheat pathogen Zymoseptoria tritici and reveal that Mg1LysM is involved in the formation of two kinds of dimers; a chitin-dependent dimer as well as a chitin-independent homodimer. In this manner, Mg1LysM gains the capacity to form a supramolecular structure by chitin-induced oligomerization of chitin-independent Mg1LysM homodimers, a property that confers protection to fungal cell walls against host chitinases.


Assuntos
Ascomicetos/química , Quitina/química , Proteínas Fúngicas/química , Hifas/química , Multimerização Proteica , Ascomicetos/genética , Ascomicetos/metabolismo , Quitina/genética , Quitina/metabolismo , Cladosporium/química , Cladosporium/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Hifas/genética , Hifas/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Estrutura Quaternária de Proteína , Triticum/genética , Triticum/metabolismo , Triticum/microbiologia
15.
Arch Microbiol ; 202(8): 2245-2253, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32533207

RESUMO

Venturia inaequalis is a notorious fungal pathogen and show classical gene for gene interaction with its apple host. Neutral markers provide clues about history, evolutionary potential, genetic diversity and population structure of V. inaequalis. The genetic diversity and population structure of fungus indicates that the pathogen is highly diverse with the capacity to breach the scab resistance genes. In the present study, we collected 108 V. inaequalis isolates from three apple cultivars differing in Rvi1 resistance gene. Based on the AMOVA, the variation was mostly distributed among the isolates, providing evidence of non-existence of subpopulation in orchards thus founder population is difficult to arise in Kashmir apple orchards. Pair wise genetic differentiation is less due to regular occurrence of gene flow between the populations residing on different orchard as infected material is transported without stringent quarantine measures. Based on principal coordinate analysis and clustering algorithm as implemented in STRUCTURE, we observed admixture between the two subpopulations, which is quite low, suggesting the existence of pre-zygotic and post-zygotic barriers to gene flow and we cannot rule out the existence of other structures shared by accessions belonging to different varieties. Due to the continuous increase in introduction and monoculture of apple varieties, mixed orchard with different host resistance specificities are more suitable for managing the apple scab in Kashmir valley.


Assuntos
Ascomicetos/fisiologia , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita/fisiologia , Malus/microbiologia , Ascomicetos/genética , Evolução Biológica , Análise por Conglomerados , Interações Hospedeiro-Parasita/genética , Índia , Malus/genética , Doenças das Plantas/microbiologia
16.
J Genet ; 992020.
Artigo em Inglês | MEDLINE | ID: mdl-32529988

RESUMO

Rice blast disease, caused by Magnaporthe oryzae, is one of the most importance diseases of rice production worldwide. The keyrole of defense mechanism to combat this fungus in rice follows the gene-for-gene concept, which a plant resistant (R) gene product recognizes a fungal avirulent (AVR) effector and triggers the hypersensitive response. However, the AVR genes have been shown to be rapidly evolving resulting in high level of genetic diversity. The aims of this study were to examine the nucleotide sequence variation of AVR-Pita1 gene in Thai rice blast isolates and to identify the severity of blast disease using isogenic line of Pita gene. Seventy-six rice blast isolates collected from different parts of Thailand were used. Gene specific primers for AVR-Pita1 gene coding sequence were designed and used for identifying the genetic diversity of AVR-Pita1 gene by PCR amplification and sequencing. The obtained sequences were analysed for genetic variation and genetic relationship. Our results revealed the association between the sequence variations of AVR-Pita1 and selective forces from Pita gene. This phenomenon demonstrated the coevolution between rice blast resistant gene in rice and avirulent gene in blast fungus. The information about variation and evolutionary mechanisms of AVR gene obtained from this study can be used in rice blast resistant breeding programme.


Assuntos
Ascomicetos/genética , Ascomicetos/isolamento & purificação , Sequência de Bases/genética , Variação Genética , Oryza , Filogenia , Reação em Cadeia da Polimerase , Fatores de Virulência
17.
Phytopathology ; 110(11): 1756-1758, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32515644

RESUMO

Powdery mildew, caused by Podosphaera leucotricha, is an economically important disease of apple and pear trees. A single monoconidial strain (PuE-3) of this biotrophic fungus was used to extract DNA for Illumina sequencing. Data were assembled to form a draft genome of 43.8 Mb consisting of 8,921 contigs, 9,372 predicted genes, and 96.1% of complete benchmarking universal single copy orthologs (BUSCOs). This is the first reported genome sequence of P. leucotricha that will enable studies of the population biology, epidemiology, and fungicide resistance of this pathogen. Furthermore, this resource will be fundamental to uncover the genetic and molecular mechanisms of the apple-powdery mildew interaction, and support future pome fruit breeding efforts.


Assuntos
Ascomicetos , Fungicidas Industriais , Malus , Ascomicetos/genética , Sequenciamento de Nucleotídeos em Larga Escala , Malus/genética , Doenças das Plantas
18.
Phytopathology ; 110(11): 1781-1790, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32567977

RESUMO

The ascomycete fungus Pyrenophora tritici-repentis is the causal agent of tan spot of wheat. The disease can occur on both common wheat (Triticum aestivum) and durum wheat (T. turgidum ssp. durum) and has potential to cause significant yield and quality losses. The fungal pathogen is known to produce necrotrophic effectors (NEs) that act as important virulence factors. Based on the NE production and virulence on a set of four differentials, P. tritici-repentis isolates have been classified into eight races. Race 4 produces no known NEs and is avirulent on the differentials. From a fungal collection in North Dakota, we identified several isolates that were classified as race 4. These isolates caused no or little disease on all common wheat lines including the differentials; however, they were virulent on some durum cultivars and tetraploid wheat accessions. Using two segregating tetraploid wheat populations and quantitative trait locus mapping, we identified several genomic regions significantly associated with disease caused by two of these isolates, some of which have not been previously reported. This is the first report that race 4 is virulent on tetraploid wheat, likely utilizing unidentified NEs. Our findings further highlight the insufficiency of the current race classification system for P. tritici-repentis.


Assuntos
Ascomicetos , Triticum , Ascomicetos/genética , Humanos , North Dakota , Doenças das Plantas , Tetraploidia , Triticum/genética
19.
Mol Plant Microbe Interact ; 33(9): 1095-1097, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32420795

RESUMO

Olive leaf scab, also known as peacock spot disease, caused by Venturia oleaginea (syn. Spilocaea oleaginea and Fusicladium oleagineum) is the most widespread and economically important fungal disease attacking olive in production countries. Here, we report the first highly contiguous whole-genome sequence (46.08 Mb) of one isolate, YUN35, of V. oleaginea. The described genome sequence and annotation resource will be useful to study the fungal biology, pathogen-host interaction, characterization of genes of interest, and population genetic diversity.


Assuntos
Ascomicetos , Genoma Fúngico , Olea/microbiologia , Doenças das Plantas/microbiologia , Ascomicetos/genética
20.
Mol Plant Microbe Interact ; 33(9): 1092-1094, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32460609

RESUMO

Phoma sorghina var. saccharum is a fungal pathogen that causes sugarcane twisted leaf disease in China. Here, we report complete genome assemblies of the Phoma sorghina var. saccharum isolate BS2-1, generated using single-molecule real-time sequencing. We present a high-quality genome sequence of a Phoma isolate that was assembled into 22 contigs with an N50 length of 1.92 Mb, a total length of 33.12 Mb, and a GC content of 52.12%. A total of 7,870 genes were annotated, using a combination of gene prediction tools, including 281 noncoding RNAs, 515 genes encoding carbohydrate-active enzymes, 2,440 genes associated with pathogen-host interactions, and 583 genes encoding secreted proteins. The complete genome sequence will be useful for understanding host-pathogen interaction and for improving disease management strategies.


Assuntos
Ascomicetos , Genoma Fúngico , Doenças das Plantas/microbiologia , Saccharum/microbiologia , Ascomicetos/genética , China , Folhas de Planta
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