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1.
Plant Dis ; 104(1): 227-238, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31647694

RESUMO

California has been invaded by two distinct Euwallacea spp. that vector unique plant pathogenic symbiotic fungi on multiple hosts and cause Fusarium dieback. The objective of this study was to develop multiplex real-time quantitative PCR assays using hydrolysis probes targeting the ß-tubulin gene to detect, distinguish, and quantify fungi associated with the polyphagous shot hole borer (PSHB; Euwallacea whitfordiodendrus, Fusarium euwallaceae, Graphium euwallaceae, and Paracremonium pembeum) as well as the Kuroshio shot hole borer (KSHB; Euwallacea kuroshio, Fusarium kuroshium, and Graphium kuroshium) from various sample types. Absolute quantification reaction efficiencies ranged from 88.2 to 104.3%, with a coefficient of determination >0.992 and a limit of detection of 100 copies µl-1 for all targets across both assays. Qualitative detection using the real-time assays on artificially inoculated avocado shoot extracts showed more sensitivity compared with conventional fungal isolation from wood. All symbiotic fungi, except P. pembeum, from PSHB and KSHB female heads were detectable and quantified. Field samples from symptomatic Platanus racemosa, Populus spp., and Salix spp. across 17 of 26 city parks were positively identified as PSHB and KSHB through detection of their symbiotic fungi, and both were found occurring together on five trees from three different park locations. The molecular assays presented here can be utilized to accurately identify fungi associated with these invasive pests in California.


Assuntos
Ascomicetos , Fusarium , Reação em Cadeia da Polimerase em Tempo Real , Gorgulhos , Animais , Ascomicetos/classificação , Ascomicetos/genética , California , Feminino , Fusarium/classificação , Fusarium/genética , Espécies Introduzidas , Limite de Detecção , Gorgulhos/microbiologia
2.
Plant Dis ; 104(1): 246-254, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31644390

RESUMO

Species within clade 2 of the Fusarium solani species complex (FSSC) are significant pathogens of dry bean (Phaseolus vulgaris) and soybean (Glycine max), causing root rot and/or sudden death syndrome (SDS). These species are morphologically difficult to distinguish and often require molecular tools for proper diagnosis to a species level. Here, a TaqMan probe-based quantitative PCR (qPCR) assay was developed to distinguish Fusarium brasiliense from other closely related species within clade 2 of the FSSC. The assay displays high specificity against close relatives and high sensitivity, with a detection limit of 100 fg. This assay was able to detect F. brasiliense from purified mycelia, infected dry bean roots, and soil samples throughout Michigan. When multiplexed with an existing qPCR assay specific to Fusarium virguliforme, accurate quantification of both F. brasiliense and F. virguliforme was obtained, which can facilitate accurate diagnoses and identify coinfections with a single reaction. The assay is compatible with multiple qPCR thermal cycling platforms and will be helpful in providing accurate detection of F. brasiliense. Management of root rot and SDS pathogens in clade 2 of the FSSC is challenging and must be done proactively, because no midseason management strategies currently exist. However, accurate detection can facilitate management decisions for subsequent growing seasons to successfully manage these pathogens.


Assuntos
Fusarium , Doenças das Plantas , Reação em Cadeia da Polimerase , Soja , Fusarium/genética , Michigan , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Microbiologia do Solo , Soja/microbiologia , Especificidade da Espécie
3.
Biochim Biophys Acta Proteins Proteom ; 1868(1): 140268, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31491588

RESUMO

BACKGROUND: Cytochrome P450 enzymes (CYPs) are monooxygenases present in every domain of life. In fungi CYPs are involved in virulence. Fusarium wilt of lettuce, caused by F. oxysporum f. sp. lactucae, is the most serious disease of lettuce. F. oxysporum f.sp. lactucae MSA35 is an antagonistic fungus. Pathogenic formae specialis of F. oxysporum possess a CYP belonging to the new family CYP505. This enzyme hydroxylates saturated fatty acids that play a role in plant defence. METHODS: Molecular tools were adopted to search for cyp505 gene in MSA35 genome. cyp505 gene expression analysis in pathogenic and antagonistic Fusarium was performed. The enzyme was expressed in its recombinant form and used for catalytic reactions with fatty acids, the products of which were characterized by mass spectrometry analysis. RESULTS: A novel MSA35 self-sufficient CYP505 is differentially expressed in antagonistic and pathogenic F. oxysporum. Its expression is induced by the host plant lettuce in both pathogenesis and antagonism during the early phase of the interaction, while it is silenced during the late phase only in antagonistic Fusarium. Mass-spectrometry investigations proved that CYP505A1 mono-hydroxylates lauric, palmitic and stearic acids. CONCLUSIONS: The ability of CYP505A1 to oxidize fatty acids present in the cortical cell membranes together with its differential expression in its Fusarium antagonistic form point out to the possibility that this enzyme is associated with Fusarium pathogenicity in lettuce. GENERAL SIGNIFICANCE: The CYP505 clan is present in pathogenic fungal phyla, making CYP505A1 enzyme a putative candidate as a new target for the development of novel antifungal molecules.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Proteínas Fúngicas/genética , Fusarium/enzimologia , Sequência de Bases , Catálise , Membrana Celular/metabolismo , Sistema Enzimático do Citocromo P-450/química , Ácidos Graxos/química , Proteínas Fúngicas/química , Fusarium/genética , Fusarium/patogenicidade , Fusarium/fisiologia , Interações Hospedeiro-Patógeno , Alface/microbiologia , Filogenia , Proteínas Recombinantes/química , Virulência
4.
J Med Microbiol ; 68(11): 1641-1648, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31526456

RESUMO

Introduction: Onychomycosis is a debilitating, difficult-to-treat nail fungal infection with increasing prevalence worldwide. The main etiological agents are dermatophytes, which are common causative pathogens in superficial fungal mycoses. Conventional detection methods such as fungal culture have low sensitivity and specificity and are time-consuming.Aim: The main objective of this study was to design, develop and validate a real-time probe-based multiplex qPCR assay for the detection of dermatophytes and Fusarium species.Methodology: The performance characteristics of the qPCR assays were evaluated. The multiplex qPCR assays targeted four genes (assay 1: pan-dermatophytes/Fusarium spp.; assay 2: Trichophyton rubrum/Microsporum spp.). Analytical validation was accomplished using 150 fungal isolates and clinical validation was done on 204 nail specimens. The performance parameters were compared against the gold standard (fungal culture) and expanded gold standard (culture in conjunction with sequencing).Results: Both the single-plex and multiplex qPCR assays performed well especially when compared against the expanded gold standard. Among the 204 tested nail specimens, the culture method showed that 125 (61.3 %) were infected with at least one organism, of which 40 yielded positive results for dermatophytes and Fusarium spp. These target organisms detected include 20 dermatophytes and 22 Fusarium spp. The developed qPCR assays demonstrated excellent limit of detection, efficiency, coefficient of determination, analytical and clinical sensitivity and specificity.Conclusion: The multiplex qPCR assays were reliable for the diagnosis of onychomycosis, with shorter turn-around time as compared to culture method. This aids in the planning of treatment strategies to achieve optimal therapeutic outcome.


Assuntos
Arthrodermataceae/isolamento & purificação , Dermatomicoses/microbiologia , Fusariose/microbiologia , Fusarium/isolamento & purificação , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Arthrodermataceae/classificação , Arthrodermataceae/genética , Dermatomicoses/diagnóstico , Fusariose/diagnóstico , Fusarium/genética , Humanos , Sensibilidade e Especificidade
5.
PLoS Pathog ; 15(9): e1007791, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31545842

RESUMO

Iron homeostasis is important for growth, reproduction and other metabolic processes in all eukaryotes. However, the functions of ATP-binding cassette (ABC) transporters in iron homeostasis are largely unknown. Here, we found that one ABC transporter (named FgAtm1) is involved in regulating iron homeostasis, by screening sensitivity to iron stress for 60 ABC transporter mutants of Fusarium graminearum, a devastating fungal pathogen of small grain cereal crops worldwide. The lack of FgAtm1 reduces the activity of cytosolic Fe-S proteins nitrite reductase and xanthine dehydrogenase, which causes high expression of FgHapX via activating transcription factor FgAreA. FgHapX represses transcription of genes for iron-consuming proteins directly but activates genes for iron acquisition proteins by suppressing another iron regulator FgSreA. In addition, the transcriptional activity of FgHapX is regulated by the monothiol glutaredoxin FgGrx4. Furthermore, the phosphorylation of FgHapX, mediated by the Ser/Thr kinase FgYak1, is required for its functions in iron homeostasis. Taken together, this study uncovers a novel regulatory mechanism of iron homeostasis mediated by an ABC transporter in an important pathogenic fungus.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas Fúngicas/metabolismo , Fusarium/metabolismo , Fusarium/patogenicidade , Ferro/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Sequência de Bases , DNA Fúngico/genética , Grão Comestível/microbiologia , Proteínas Fúngicas/genética , Fusarium/genética , Deleção de Genes , Genes Fúngicos , Homeostase , Proteínas com Ferro-Enxofre/genética , Proteínas com Ferro-Enxofre/metabolismo , Modelos Biológicos , Mutação , Doenças das Plantas/microbiologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Sideróforos/genética , Sideróforos/metabolismo , Estresse Fisiológico
6.
J Basic Microbiol ; 59(11): 1105-1111, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31497881

RESUMO

Six wheat cultivars with varied resistance to Gibberella zeae (Anamorph, Fusarium graminearum Schwabe) were inoculated with six monoconidial strains of G. zeae to investigate the effect of wheat resistance to Fusarium head blight on deoxynivalenol (DON) contents. Samples were selected from grains from each plot, and heavily infected kernels and sound (uninfected) kernels prepared at 10% and 20% Fusarium-diseased kernels (FDK). The proportions of scabbed spikelets (PSS) in the field, total DON (containing DON, 3-acetyl-deoxynivalenol, and 15-acetyl-deoxynivalenol), and F. graminearum DNA (Tri5 DNA) in the samples were quantified in 2006 and 2007. PSS exhibited significant variability among the six wheat cultivars. Potential DON production also had significant differences among the six strains. DON toxin concentrations and F. graminearum DNA (Tri5 DNA) showed no significant differences among the six wheat cultivars following inoculation with similar F. graminearum strains at similar FDK levels and at similar disease severity after culture in similar conditions. DON content in grains of the tested wheat cultivars varied with inoculation strain and FDK level, but not with the resistance level of the cultivars to F. graminearum.


Assuntos
Resistência à Doença , Fusarium/patogenicidade , Micotoxinas/análise , Tricotecenos/análise , Triticum/química , Triticum/microbiologia , DNA Fúngico/análise , Grão Comestível/química , Grão Comestível/microbiologia , Fusarium/genética , Fusarium/metabolismo , Micotoxinas/metabolismo , Doenças das Plantas/microbiologia , Tricotecenos/metabolismo
7.
Microbiology ; 165(10): 1075-1085, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31390325

RESUMO

Fusarium verticillioides is one of the key fungal pathogens responsible for maize stalk rot. While stalk rot pathogens are prevalent worldwide, our understanding of the stalk rot virulence mechanism in pathogenic fungi is still very limited. We previously identified the F. verticillioides FvSYN1 gene, which was demonstrated to play an important role in maize stalk rot virulence. FvSyn1 belongs to a family of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins that play critical roles in a variety of developmental processes. In this study, we further characterized the cellular features of the FvSyn1 protein, namely how different motifs contribute to development and virulence in F. verticillioides by generating motif-specific deletion mutants. Microscopic observation showed that the ∆Fvsyn1 mutant exhibits rough and hyper-branched hyphae when compared to the wild-type progenitor. Moreover, the ∆Fvsyn1 mutant was sensitive to cell wall stress agents, resulting in vegetative growth reduction. We showed that the FvSyn1::GFP protein is associated with the endomembrane, but this did not clarify why the deletion of FvSyn1 led to stress sensitivity and aberrant hyphal development. Characterization of the FvSyn1 domains indicated that both the syntaxin N-terminus (SynN) domain and the SNARE C-terminus domain play distinct roles in fungal development, but also function collectively in the context of virulence. We also determined that two domains in FvSyn1 are not required for fumonisin production. Interestingly, these two domains were involved in carbon nutrient utilization, including pectin, starch and sorbitol. This study further characterized the role of FvSyn1 domains in hyphal growth, cell wall stress response and virulence in F. verticillioides.


Assuntos
Proteínas Fúngicas/química , Fusarium/crescimento & desenvolvimento , Fusarium/patogenicidade , Proteínas SNARE/química , Carbono/metabolismo , Parede Celular/fisiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fusarium/genética , Fusarium/metabolismo , Hifas/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Domínios Proteicos , Proteínas SNARE/genética , Proteínas SNARE/metabolismo , Deleção de Sequência , Esporos Fúngicos/crescimento & desenvolvimento , Estresse Fisiológico , Virulência , Zea mays/microbiologia
8.
Phytopathology ; 109(12): 2124-2131, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31418639

RESUMO

Fusarium graminearum is primarily understood as an agricultural pathogen affecting cereal crops, but its host range also includes diverse, noncultivated grasses ubiquitous across agricultural and natural environments. Wild grasses may select for the production of diverse toxin variants (chemotypes) and serve as reservoirs of genetic diversity or sources of disease-inciting inoculum. Populations at the intersection of wheat and wild grass communities were described using 909 isolates collected from wheat spikes, wild grass spikes, and overwintered wild grass stems found at natural and agricultural sites in regions of high and low crop production. Trichothecene (TRI) genotypes correlated to pathogen chemotype were predicted from two loci, and multilocus genotypes (MLGs) were determined using eight microsatellite loci. The genetic diversity of wild grass and wheat-derived populations was comparable, and their differentiation was low. Duplicate MLGs were rare even in samples collected from a single square meter, although they could be found in multiple hosts, environments, regions, and years. TRI genotype frequencies differed between region and land use. Admixture between TRI genotype-defined populations, which correspond to three previously described sympatric North American populations, was detected and was highest in a region with remote host communities and little agricultural production. Nonagricultural environments may maintain different pathogen TRI genotypes than wheat fields and provide an opportunity for recombination between isolates from different F. graminearum populations. A lack of structural barriers suggests that pathogen gene flow is uninhibited between wheat and wild grass communities, and the recovery of putative clones from multiple hosts and environments provides initial evidence that noncultivated grasses are a source of local and regional inoculum.


Assuntos
Fusarium , Variação Genética , Genética Populacional , Poaceae , Triticum , Fusarium/genética , Fluxo Gênico , Genótipo , Micotoxinas/genética , New York , Doenças das Plantas/microbiologia , Poaceae/microbiologia , Tricotecenos , Triticum/microbiologia
9.
Microbiol Res ; 227: 126296, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421712

RESUMO

Heat shock proteins (Hsp) are important factors in the response of organisms to oscillations in environmental conditions. Although Hsp have been studied for a long time, little is known about this protein class in Trichoderma species. Here we studied the expression of Hsp genes during T. asperellum growth, and mycoparasitism against two phytopathogens: Sclerotinia sclerotiorum and Fusarium oxysporum, as well as during thermal stress. The expression levels of these genes were observed by real-time PCR and they showed to be differentially expressed under these conditions. We verified that the TaHsp26c, TaHsp70b and TaHsp70c genes were differentially expressed over time, indicating that these genes can be developmentally regulated in T. asperellum. Except for TaHsp26a, all other genes analyzed were induced in the post-contact condition when T. asperellum was cultured in a confrontation plate assay against itself. Additionally, TaHsp26b, TaHsp26c, TaHsp90, TaHsp104a and TaHsp104b were induced during initial contact between T. asperellum hyphae, suggesting that these proteins must play a role in the organism´s self-recognition mechanism. When we examined gene expression during mycoparasitism, we observed that some genes were induced both by S. sclerotiorum and F. oxysporum, while others were not induced during interaction with either of the phytopathogens. Furthermore, we observed some genes induced only during confrontation against S. sclerotiorum, indicating that the expression of Hsp genes during mycoparasitism seems to be modulated by the phytopathogen. To assess whether such genes are expressed during temperature oscillations, we analyzed their transcription levels during thermal and cold shock. We observed that except for the TaHsp70c gene, all others presented high transcript levels when T. asperellum was submitted to high temperature (38 °C), indicating their importance in the response to heat stress. The TaHsp70c gene was significantly induced only in cold shock at 4 °C. Our results show the importance of Hsp proteins during self-recognition, mycoparasitism and thermal stress in T. asperellum.


Assuntos
Regulação Fúngica da Expressão Gênica/genética , Genes Fúngicos/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/fisiologia , Trichoderma/genética , Sequência de Aminoácidos , Ascomicetos/genética , Fusarium/genética , Resposta ao Choque Térmico/genética , Hifas/genética , Hifas/crescimento & desenvolvimento , Interações Microbianas , Doenças das Plantas/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Alinhamento de Sequência , Estresse Fisiológico/genética , Temperatura Ambiente , Transcriptoma , Trichoderma/crescimento & desenvolvimento
10.
Plant Dis ; 103(10): 2536-2540, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31424998

RESUMO

Fusarium head blight, also called scab, is caused by Fusarium graminearum and is one of the most important destructive diseases of wheat. The frequency of carbendazim resistance in 1,132 isolates of F. graminearum recovered from fields in different regions of Henan Province in 2016, 2017, and 2018 was determined. A total of 31 F. graminearum isolates resistant to carbendazim were detected, including 30 moderately resistant isolates and one highly resistant isolate. The frequency of resistance of F. graminearum isolates to carbendazim was 2.7%. The range of effective concentration (EC50) values of 1,101 sensitive isolates and 30 moderately resistant isolates was 0.08 to 0.98 µg ml-1 and 2.73 to 13.28 µg ml-1, respectively. The mean ± SD EC50 value was 0.55 ± 0.13 µg ml-1 and 5.61 ± 2.58 µg ml-1, respectively. The EC50 value of the highly resistant isolate was 21.12 µg ml-1. Point mutation types of the carbendazim-resistant isolates were characterized by cloning the ß2-tubulin gene of 31 resistant isolates. Three point mutation types at amino acids F167Y, E198Q, and E198L in the ß2-tubulin gene of resistant isolates were identified. Among 31 resistant isolates, the frequency of point mutation types in F167Y, E198Q, and E198L of the ß2-tubulin gene was 71.0, 25.8, and 3.2%, respectively. The data indicate that F. graminearum has developed resistance to carbendazim in Henan Province, and single point mutations at amino acid F167Y were the predominant type of mutation detected.


Assuntos
Benzimidazóis , Carbamatos , Farmacorresistência Fúngica , Fusarium , Triticum , Benzimidazóis/farmacologia , Carbamatos/farmacologia , Farmacorresistência Fúngica/genética , Fungicidas Industriais , Fusarium/efeitos dos fármacos , Fusarium/genética , Genes de Plantas/genética , Mutação Puntual , Triticum/microbiologia , Tubulina (Proteína)/genética
11.
Genes (Basel) ; 10(9)2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31466418

RESUMO

Fusarium oxysporum is the most important pathogen of potatoes which causes post-harvest destructive losses and deteriorates the market value of potato tubers worldwide. Here, F. oxysporum was used as a host pathogen model system and it was revealed that autophagy plays a vital role as a regulator in the morphology, cellular growth, development, as well as the pathogenicity of F. oxysporum. Previous studies based upon identification of the gene responsible for encoding the autophagy pathway components from F. oxysporum have shown putative orthologs of 16 core autophagy related-ATG genes of yeast in the genome database which were autophagy-related and comprised of ubiquitin-like protein atg3. This study elucidates the molecular mechanism of the autophagy-related gene Foatg3 in F. oxysporum. A deletion (∆) mutants of F. oxysporum (Foatg3∆) was generated to evaluate nuclear dynamics. As compared to wild type and Foatg3 overexpression (OE) strains, Foatg3∆ strains failed to show positive MDC (monodansylcadaverine) staining which revealed that Foatg3 is compulsory for autophagy in F. oxysporum. A significant reduction in conidiation and hyphal growth was shown by the Foatg3∆ strains resulting in loss of virulence on potato tubers. The hyphae of Foatg3∆ mutants contained two or more nuclei within one hyphal compartment while wild type hyphae were composed of uninucleate hyphal compartments. Our findings reveal that the vital significance of Foatg3 as a key target in controlling the dry rot disease in root crops and potato tubers at the postharvest stage has immense potential of disease control and yield enhancement.


Assuntos
Proteínas Relacionadas à Autofagia/genética , Proteínas Fúngicas/genética , Fusarium/genética , Proteínas Relacionadas à Autofagia/metabolismo , Proteínas Fúngicas/metabolismo , Fusarium/crescimento & desenvolvimento , Fusarium/patogenicidade , Deleção de Genes , Hifas/genética , Hifas/crescimento & desenvolvimento , Solanum tuberosum/microbiologia , Virulência/genética
12.
Int J Mol Sci ; 20(15)2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382478

RESUMO

Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is well-known as the causal agent of Fusarium wilt of banana and is one of the most destructive phytopathogens for banana plants. The molecular mechanisms underlying Foc TR4 virulence remain elusive. Here, we demonstrate that a cerato-platanin (CP) protein, FocCP1, functions as a virulence factor that is required by Foc TR4 for penetration and full virulence. The FocCP1 gene was expressed in every condition studied, showing a high transcript level in planta at the early stage of infection. Infiltration of the recombinant FocCP1 protein induced significant cell death and upregulated defence-related gene expression. FocCP1 knock-out strains showed a significant decrease in aerial growth rather than aqueous growth, which is reminiscent of hydrophobins. Furthermore, deletion of FocCP1 significantly reduced virulence and dramatically reduced infective growth in banana roots, likely resulting from a defective penetration ability. Taken together, the results of this study provide novel insight into the function of the recently identified FocCP1 as a virulence factor in Foc TR4.


Assuntos
Proteínas Fúngicas/genética , Fusarium/patogenicidade , Musa/microbiologia , Doenças das Plantas/microbiologia , Fatores de Virulência/genética , Proteínas Fúngicas/metabolismo , Fusarium/genética , Fusarium/fisiologia , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Interações Hospedeiro-Patógeno , Virulência , Fatores de Virulência/metabolismo
13.
Phytopathology ; 109(12): 2142-2151, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31369361

RESUMO

Fusarium solani is a soilborne fungus that is a pathogen to >100 plant species. It is the causal agent of crown and root rot in strawberry. We collected 100 F. solani isolates from diseased plants and soils from two distinct geographic areas of strawberry production in Spain: plant nurseries located in the north-central region of the country and fruit production fields located in the southwestern region. The aims of this study were to accurately identify the isolates within the Fusarium solani species complex (FSSC) based on multilocus sequence typing, determine the genetic diversity and population structure of strawberry-associated FSSC based on phylogenetic analysis, and determine the vegetative compatibility among isolates in both strawberry production areas. Seven phylogenetic species, restricted to clade 3 of FSSC, were defined in the Spanish strawberry crops, showing a regional variation of species composition. Isolates from nurseries were composed of four phylogenetic species (i.e., FSSC 2, FSSC 5, FSSC 9, and an unknown FSSC species) that matched with five vegetative compatibility groups (VCGs). Isolates from fruit production fields included five phylogenetic species (i.e., FSSC 2, FSSC 3 + 4, FSSC 5, FSSC 6, and FSSC 11) distributed into 29 VCGs not correlated with phylogenetic groups. FSSC 5 and FSSC 2 were the most abundant species in nurseries and fruit production fields, respectively, and they were the only species present in both production areas. Of the 47 sequence-based haplotypes defined, no haplotypes were shared between nurseries and fruit production fields. Pathogenic isolates were present in all but FSSC 6 and FSSC 9 species, and FSSC 3 + 4 contained the higher percentage of pathogenic isolates. No relationship was observed between pathogenicity and the source of isolates (plant or soil). Generally, species present in fruit production fields showed higher genetic diversity than those present in nurseries. This work can contribute to understanding the diversity of this species complex in Spanish strawberry production areas, which will be useful for developing integrated disease management strategies.


Assuntos
Fragaria , Fusarium , Variação Genética , Filogenia , Fragaria/microbiologia , Fusarium/classificação , Fusarium/genética , Tipagem de Sequências Multilocus , Doenças das Plantas/microbiologia , Espanha
14.
J Med Microbiol ; 68(10): 1489-1496, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31419209

RESUMO

Introduction. The remarkable intrinsic resistance of Fusarium species to most antifungal agents results in high mortality rates in the immunocompromised population.Aims. This study aimed to investigate the epidemiology, clinical features and antifungal susceptibility of Fusarium isolates in patients with invasive fusariosis.Methodology. A total of 27 patients admitted to a referral hospital from January 2008 to June 2017 were evaluated. Antifungal susceptibility testing of isolates was performed by broth microdilution according to the Clinical and Laboratory Standards Institute guidelines.Results. Haematological malignancy was the predominant underlying condition, with an incidence of invasive fusariosis of 14.8 cases per 1000 patients with acute lymphoid leukaemia and 13.1 cases per 1000 patients with acute myeloid leukaemia. The Fusarium solani species complex (FSSC) was the most frequent agent group, followed by the Fusarium oxysporum species complex (FOSC). Voriconazole showed the best activity against Fusarium, followed by amphotericin B. Itraconazole showed high minimum inhibitory concentration values, indicating in vitro resistance. Clinical FSSC isolates were significantly (P<0.05) more resistant to amphotericin B and voriconazole than FOSC isolates.Conclusion. The present antifungal susceptibility profiles indicate a high incidence of fusariosis in patients with haematological malignancy. Species- and strain-specific differences in antifungal susceptibility exist within Fusarium in this setting.


Assuntos
Fusariose/microbiologia , Fusarium/efeitos dos fármacos , Fusarium/isolamento & purificação , Neoplasias Hematológicas/microbiologia , Adolescente , Adulto , Idoso , Anfotericina B/farmacologia , Antifúngicos/farmacologia , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Fusariose/epidemiologia , Fusarium/classificação , Fusarium/genética , Neoplasias Hematológicas/epidemiologia , Humanos , Itraconazol/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Filogenia , Voriconazol/farmacologia , Adulto Jovem
15.
PLoS One ; 14(7): e0214230, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31299046

RESUMO

Benzoxazinoid (Bx) metabolites produced by wheat and other members of the Poaceae have activity against Fusarium sp. that cause cereal diseases including Fusarium head blight (FHB) on wheat and barley. Certain Bx metabolites can be detoxified by Fusarium sp. with the arylamine N-acetyltransferase NAT1. Investigation of this pathway may reveal strategies for increasing FHB resistance, such as selection for higher levels of Bx metabolites within existing germplasm and/or engineering fungal susceptibility via host induced silencing of NAT1. We assessed the reactions of fifteen wheat cultivars or breeding lines adapted to the Northwestern United States to infection with F. graminearum Δnat1 mutants that should be sensitive to Bx metabolites. Significant differences were noted in disease severity and deoxynivalenol (DON) among the cultivars 21 d after inoculation with either mutant or wildtype (PH1) strains. Mutant vs. wildtype strains did not result in significant variation for infection severity (as measured by % infected florets), but inoculation with Δnat1 mutants vs. wildtype resulted in significantly lower DON concentrations in mature kernels (p < 0.0001). Of the cultivars tested, HRS3419 was the most resistant cultivar to PH1 (severity = 62%, DON = 45 ppm) and Δnat1 mutants (severity = 61%, DON = 30 ppm). The cultivar most susceptible to infection was Kelse with PH1 (severity = 100%, DON = 292 ppm) and Δnat1 mutants (severity = 100%, DON = 158 ppm). We hypothesized that sub-lethal Bx metabolite levels may suppress DON production in F. graminearum Δnat1 mutants. In vitro assays of Bx metabolites BOA, MBOA, and DIMBOA at 30 µM did not affect growth, but did reduce DON production by Δnat1 and PH1. Although the levels of Bx metabolites are likely too low in the wheat cultivars we tested to suppress FHB, higher levels of Bx metabolites may contribute towards reductions in DON and FHB.


Assuntos
Arilamina N-Acetiltransferase/genética , Proteínas Fúngicas/genética , Fusarium/genética , Doenças das Plantas/microbiologia , Tricotecenos/metabolismo , Triticum/microbiologia , Fusarium/enzimologia , Deleção de Genes , Interações Hospedeiro-Patógeno , Triticum/metabolismo
16.
BMC Genomics ; 20(1): 570, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291889

RESUMO

BACKGROUND: Cucumber Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum (Foc), is one of the most notorious diseases in cucumber production. Our previous research showed the virulence of Foc significantly increases over consecutive rounds of infection in a resistant cultivar. To understand the virulence variation of Foc under host pressure, the mildly virulent strain foc-3b (WT) and its virulence-enhanced variant Ra-4 (InVir) were selected and their transcriptome profiles in infected cucumber roots were analyzed at 24 h after inoculation (hai) and 120 hai. RESULTS: A series of differentially expressed genes (DEGs) potentially involved in fungal pathogenicity and pathogenicity variation were identified and prove mainly involved in metabolic, transport, oxidation-reduction, cell wall degradation, macromolecules modification, and stress and defense. Among these DEGs, 190 up- and 360 down-regulated genes were expressed in both strains, indicating their importance in Foc infection. Besides, 286 and 366 DEGs showed up-regulated expression, while 492 and 214 showed down-regulated expression in InVir at 24 and 120 hai, respectively. These DEGs may be involved in increased virulence. Notably, transposases were more active in InVir than WT, indicating transposons may contribute to adaptive evolution. CONCLUSIONS: By a comparative transcriptome analysis of the mildly and highly virulent strains of Foc during infection of cucumber, a series of DEGs were identified that may be associated with virulence. Hence, this study provides new insight into the transcriptomic profile underlying pathogenicity and virulence differentiation of Foc.


Assuntos
Cucumis sativus/microbiologia , Fusarium/genética , Fusarium/patogenicidade , Perfilação da Expressão Gênica , Adaptação Fisiológica/genética , Fusarium/fisiologia , Redes Reguladoras de Genes , Raízes de Plantas/microbiologia , Especificidade da Espécie , Virulência/genética
17.
Int J Food Microbiol ; 306: 108267, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31330453

RESUMO

Fusarium incarnatum-equiseti species complex (FIESC) is commonly detected in Brazilian rice, but knowledge of the species limits and their toxigenic potential is lacking. Seventy strains morphologically identified as FIESC-like, isolated from the major rice-growing regions of Brazil, were subjected to sequencing of EF-1α gene. Among them, 18 strains were selected and analyzed for their RPB2 gene sequences. Nine phylogenetic species were identified, among which eight matched the previously reported FIESC 4 (F. lacertarum), 6, 16, 17 (F. pernambucanum), 20 (F. caatingaense), 24, 26 and 29. One new phylogenetic species was identified, and named FIESC 38. Five strains formed new singleton lineages. The most dominant species were FIESC 26 (22/70 strains) and FIESC 38 (21/70), the newly identified species. The incarnatum morphotype was dominant (10 phylogenetic species) over the equiseti (4 species). Among 46 strains selected to represent all species, only 16 strains produced detectable levels of mycotoxins in vitro. FIESC 26 produced ZEA and FIESC 38 produced both ZEA and DON. ZEA was produced by nine isolates of three other species, among which few isolates produced trichothecenes: DON (5/46), NIV (3/46), 4-ANIV (2/46), 15-ADON (1/46) and 3-ADON (1/46). The T-2 and HT-2 mycotoxins were not detected. Our results contribute novel information on species limits and mycotoxin production within cereal-infecting FIESC in the southern hemisphere and provide baseline data for further exploring morphological differences among the species.


Assuntos
Fusarium/classificação , Fusarium/patogenicidade , Micotoxinas/metabolismo , Oryza/microbiologia , Tricotecenos/metabolismo , Brasil , Grão Comestível/microbiologia , Fusarium/genética , Fusarium/isolamento & purificação , Micotoxinas/genética , Fator 1 de Elongação de Peptídeos/genética , Filogenia , RNA Polimerase II/genética , Tricotecenos/genética
18.
Fungal Biol ; 123(8): 618-624, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31345416

RESUMO

This study examined the effect of climate change (CC) abiotic factors of temperature (20, 25, 30 °C), water activity (aw; 0.995, 0.98) and CO2 exposure (400, 1000 ppm) may have on (a) growth, (b) gene expression of biosynthetic toxin genes (Tri5, Tri6, Tri16), and (c) T-2/HT-2 toxins and associated metabolites by Fusarium langsethiae on oat-based media and in stored oats. Lag phases and growth were optimum at 25 °C with freely available water. This was significantly reduced at 30 °C, at 0.98 aw and 1000 ppm CO2 exposure. In oat-based media and stored oats, Tri5 gene expression was reduced in all conditions except 30 °C, 0.98 aw, elevated CO2 where there was a significant (5.3-fold) increase. The Tri6 and Tri16 genes were upregulated, especially in elevated CO2 conditions. Toxin production was higher at 25 °C than 30 °C. In stored oats, at 0.98 aw, elevated CO2 led to a significant increase (73-fold) increase in T2/HT-2 toxin, especially at 30 °C. Nine T-2 and HT-2 related metabolites were detected, including a new dehydro T-2 toxin (which correlated with T-2 production) and the conjugate, HT-2 toxin, glucuronide. This shows that CC factors may have a significant impact on growth and mycotoxin production by F. langsethiae.


Assuntos
Avena/química , Avena/microbiologia , Proteínas Fúngicas/genética , Fusarium/crescimento & desenvolvimento , Fusarium/genética , Micotoxinas/análise , Mudança Climática , Contaminação de Alimentos/análise , Armazenamento de Alimentos , Proteínas Fúngicas/metabolismo , Fusarium/química , Fusarium/metabolismo , Micotoxinas/metabolismo , Sementes/química , Sementes/microbiologia , Toxina T-2/análogos & derivados , Toxina T-2/análise , Toxina T-2/biossíntese , Toxina T-2/metabolismo
19.
J Agric Food Chem ; 67(31): 8536-8547, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31310520

RESUMO

Watermelon Fusarium wilt is a common soil-borne disease that has significantly affected its yield. In this study, fusaric acid-deficient mutant designated as ΔFUBT (mutated from Fusarium oxysporum f. sp. niveum, FON) was obtained. The ΔFUBT mutant showed significant decrease in fusaric acid production but maintained wild-type characteristics, such as in vitro colony morphology, size, and conidiation. A field pot experiment demonstrated that ΔFUBT could successfully colonize the rhizosphere and the roots of watermelon, leading to significant reduction in FON colonization in the watermelon plant. In addition, ΔFUBT inoculation significantly improved the rhizosphere microenvironment and effectively increased the resistance in watermelon. This study demonstrated that a nonpathogenic Fusarium mutant (ΔFUBT) could be developed as an effective microbial control agent to alleviate Fusarium wilt disease in watermelon and increase its yield.


Assuntos
Citrullus/microbiologia , Fusarium/genética , Micotoxinas/genética , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ácido Fusárico/metabolismo , Fusarium/crescimento & desenvolvimento , Fusarium/fisiologia , Mutação , Micotoxinas/metabolismo , Raízes de Plantas/microbiologia , Rizosfera
20.
Plant Dis ; 103(8): 2070-2075, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31215854

RESUMO

Numerous pathogen surveys have reported that diverse Fusarium spp. threaten soybean production in North and South America. However, little research has been conducted to characterize Fusarium pathogens of soybean in sub-Saharan Africa. Our objectives were to (i) identify Fusarium spp. isolated from discolored root segments of soybean grown in Ethiopia and Ghana using DNA sequence data, (ii) determine whether isolates nested in the Fusarium incarnatum-equiseti and F. sambucinum species complexes (FIESC and FSAMSC, respectively) produced trichothecene mycotoxins in vitro, and (iii) test these isolates for pathogenicity on soybean. Molecular phylogenetic analyses revealed that the trichothecene mycotoxin-producing isolates comprised three undescribed species within the FIESC and FSAMSC. Mycotoxin type B trichothecene 4,15-diacetylnivalenol or T-2 toxin and related type A neosolaniol trichothecenes were produced by 18 of the 21 isolates. Of the 12 isolates from Ethiopia and Ghana tested for their impact on seed germination, 5, comprising two undescribed phylospecies (i.e., Fusarium sp. number 3 and Fusarium sp. FIESC 2,) completely inhibited germination, whereas 4 caused no reduction in germination. Root lesions induced by all 12 isolates were greater than the uninoculated negative control. Additional variation among the isolates was reflected in differences (α = 0.05) in lesion lengths, which ranged from 34 to 67% of total root length. This is the first report characterizing FIESC and FSAMSC isolates from soybean roots in Ethiopia and Ghana.


Assuntos
Fusarium , Raízes de Plantas , Soja , Tricotecenos , Etiópia , Fusarium/classificação , Fusarium/genética , Fusarium/patogenicidade , Gana , Filogenia , Raízes de Plantas/microbiologia , Soja/microbiologia , Tricotecenos/metabolismo , Virulência
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