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1.
Sci Total Environ ; 740: 140135, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927573

RESUMO

The increasing human population requires ongoing efforts in food production. This is frequently associated with an increased use of agrochemicals, leading to environmental contamination and altering microbial communities, including human fungal pathogens that reside in the environment. Cryptococcus gattii is an environmental yeast and is one of the etiological agents of cryptococcosis. Benomyl (BEN) is a broad-spectrum fungicide used on several crops. To study the effects of agrochemicals on fungal pathogens, we first evaluated the susceptibility of C. gattii to BEN and the interactions with clinical antifungals. Antagonistic interaction between BEN and fluconazole was seen and was strain- and concentration-dependent. We then induced BEN-resistance by culturing strains in increasing drug concentrations. One strain demonstrated to be more resistant and showed increased multidrug efflux pump gene (MDR1) expression and increased rhodamine 6G efflux, leading to cross-resistance between BEN and fluconazole. Morphologically, BEN-adapted cells had a reduced polysaccharide capsule; an increased surface/volume ratio; increased growth rate in vitro and inside macrophages and also higher ability in crossing an in vitro model of blood-brain-barrier. BEN-adapted strain demonstrated to be hypervirulent in mice, leading to severe symptoms of cryptococcosis, early mortality and higher fungal burden in the organs, particularly the brain. The parental strain was avirulent in murine model. In vivo cross-resistance between BEN and fluconazole was observed, with mice infected with the adapted strain unable to present any improvement in survival and behavior when treated with this antifungal. Furthermore, BEN-adapted cells cultured in drug-free media maintained the hypervirulent and cross-resistant phenotype, suggesting a persistent effect of BEN on C. gattii. In conclusion, exposure to BEN induces cross-resistance with fluconazole and increases the virulence of C. gattii. Altogether, our results indicate that agrochemicals may lead to unintended consequences on non-target species and this could result in severe healthy problems worldwide.


Assuntos
Cryptococcus gattii , Fungicidas Industriais/farmacologia , Animais , Antifúngicos , Farmacorresistência Fúngica , Humanos , Camundongos , Testes de Sensibilidade Microbiana
2.
Pestic Biochem Physiol ; 170: 104683, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32980051

RESUMO

Root rot caused by Cylindrocarpon destructans is one of the most devastating diseases of Panax notoginseng, and Trichoderma species are potential agents for the biocontrol of fungal diseases. Thus, we screened a total of 10 Trichoderma isolates against C. destructans and selected Trichoderma atroviride T2 as an antagonistic strain for further research. 6-Pentyl-2H-pyran-2-one (6PP) was identified as an important active metabolite in the fermentation broth of the strain and exhibited antifungal activity against C. destructans. Transcriptome and metabolome analyses showed that 6PP significantly disturbed the metabolic homeostasis of C. destructans, particularly the metabolism of amino acids. By constructing a gene coexpression network, ECHS1 was identified as the hub gene correlated with 6PP stress. 6PP significantly downregulated the expression of ECHS1 at the transcriptional level and combined with the ECHS1 protein. Autophagy occurred in C. destructans cells under 6PP stress. In conclusion, 6PP may induce autophagy in C. destructans by downregulating ECHS1 at the transcriptional level and inhibiting ECHS1 protein activity. 6PP is a potential candidate for the development of new fungicides against C. destructans.


Assuntos
Fungicidas Industriais/farmacologia , Hypocreales , Trichoderma/genética , Pironas/farmacologia
3.
PLoS One ; 15(8): e0233665, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804955

RESUMO

Oligomycins are macrolide antibiotics, produced by Streptomyces spp. that show antagonistic effects against several microorganisms such as bacteria, fungi, nematodes and the oomycete Plasmopara viticola. Conidiogenesis, germination of conidia and formation of appressoria are determining factors pertaining to pathogenicity and successful diseases cycles of filamentous fungal phytopathogens. The goal of this research was to evaluate the in vitro suppressive effects of two oligomycins, oligomycin B and F along with a commercial fungicide Nativo® 75WG on hyphal growth, conidiogenesis, conidial germination, and appressorial formation of the wheat blast fungus, Magnaporthe oryzae Triticum (MoT) pathotype. We also determined the efficacy of these two oligomycins and the fungicide product in vivo in suppressing wheat blast with a detached leaf assay. Both oligomycins suppressed the growth of MoT mycelium in a dose dependent manner. Between the two natural products, oligomycin F provided higher inhibition of MoT hyphal growth compared to oligomycin B with a minimum inhibitory concentration of 0.005 and 0.05 µg/disk, respectively. The application of the compounds completely halted conidial formation of the MoT mycelium in agar medium. Further bioassays showed that these compounds significantly inhibited MoT conidia germination and induced lysis. The compounds also caused abnormal germ tube formation and suppressed appressorial formation of germinated spores. Interestingly, the application of these macrolides significantly inhibited wheat blast on detached leaves of wheat. This is the first report on the inhibition of mycelial growth, conidiogenesis, germination of conidia, deleterious morphological changes in germinated conidia, and suppression of blast disease of wheat by oligomycins from Streptomyces spp. Further study is needed to unravel the precise mode of action of these natural compounds and consider them as biopesticides for controlling wheat blast.


Assuntos
Magnaporthe/efeitos dos fármacos , Magnaporthe/patogenicidade , Oligomicinas/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Triticum/microbiologia , Agentes de Controle Biológico/farmacologia , Grão Comestível/microbiologia , Microbiologia de Alimentos , Fungicidas Industriais/farmacologia , Hifas/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Magnaporthe/crescimento & desenvolvimento , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento
4.
Plant Dis ; 104(10): 2585-2597, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32813612

RESUMO

Quinoa black stem is a new disease that affects the stems of quinoa plants and is more likely to develop under cool conditions (15 to 25°C, RH = 55 ± 2%). The typical symptoms include the formation of black necrotic lesions on the stem, which can completely wrap around the stem, causing lodging and blanking (development of 'empty' and sterile grain on the panicle). Furthermore, the pycnidia form small round protrusions on the surface of the lesions. Phylogenetic analysis revealed that representative isolates LMHS-3 and LMHS-5 were closely related to Ascochyta caulina (teleomorph: Neocamarosporium calvescens). Comprehensive morphological and molecular characterizations confirmed A. caulina as the pathogen that caused quinoa black stem. A. caulina mainly infected quinoa stems and could produce many pycnidia, but it rarely infected quinoa leaves. Pathogenicity testing showed that the most suitable temperature for the onset of quinoa black stem was from 15 to 25°C. When the temperature was increased above 30°C, the conidial germination of A. caulina became malformed, and when the temperature was decreased below 5°C, mycelium growth of A. caulina became extremely slow; thus, both extreme high and low temperatures affected the pathogenicity of A. caulina. Mancozeb and azoxystrobin fungicides were revealed to have had the strongest inhibitory effects on the conidial germination of A. caulina, and in some cases caused malformations in conidial germination. Tebuconazole and difenoconazole had the strongest inhibitory effects on A. caulina mycelial growth and less on the effects on the conidial germination. The results of the present study provide a basis for the recognition and management of quinoa black stem.


Assuntos
Chenopodium quinoa , Fungicidas Industriais/farmacologia , China , Filogenia , Doenças das Plantas , Esporos Fúngicos/efeitos dos fármacos , Virulência
5.
PLoS One ; 15(8): e0238148, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822425

RESUMO

Root treatment with oxathiapiprolin, benthiavalicarb or their mixture Zorvec-Endavia [ZE (3+7, w/w)] was shown to provide prolonged systemic protection against foliar oomycete pathogens attacking cucumber, tomato and basil. Here we report that these fungicides can effectively protect potato plants against late blight when applied to the soil in which such potato plants are grown. In two field experiments, performed in 2019 and 2020, potato plants grown in 64 L containers were treated with a soil drench of oxathiapiprolin, benthiavalicarb or ZE at 12.5, 25 or 50 mg ai/five plants in a container. Artificial inoculations with Phytophthora infestans revealed that such treated plants were protected against late blight in a dose-dependent manner all along the season. Interestingly, oxathiapiprolin persisted in the treated soil for at least 139 days, providing systemic protection against late blight to the following potato crops grown in that treated soils. Potato plants grown in loess soil in the field were either sprayed or drenched with ZE. Plants treated via the soil were significantly better protected against late blight compared to the plants treated by a spray. The data demonstrate a new strategy for season-long protection of potato against late blight by a single soil application of ZE. The systemic nature of oxathiapiprolin and benthiavalicarb composing ZE assures the translocation to the foliage of two fungicides with different modes of action. This shall minimize the risk of developing resistance against either fungicide in the treated crops.


Assuntos
Hidrocarbonetos Fluorados/administração & dosagem , Hidrocarbonetos Fluorados/farmacologia , Doenças das Plantas/prevenção & controle , Pirazóis/administração & dosagem , Pirazóis/farmacologia , Resistência à Doença/genética , Fungicidas Industriais/farmacologia , Phytophthora infestans/efeitos dos fármacos , Phytophthora infestans/patogenicidade , Raízes de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Solo , Solanum tuberosum/microbiologia
6.
Plant Dis ; 104(10): 2563-2570, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32762501

RESUMO

Rhizoctonia solani is a widely distributed soilborne plant pathogen, and can cause significant economic losses to crop production. In chemical controls, SYP-14288 is highly effective against plant pathogens, including R. solani. To examine the sensitivity to SYP-14288, 112 R. solani isolates were collected from infected rice plants. An established baseline sensitivity showed that values of effective concentration for 50% growth inhibition (EC50) ranged from 0.0003 to 0.0138 µg/ml, with an average of 0.0055 ± 0.0030 µg/ml. The frequency distribution of the EC50 was unimodal and the range of variation factor (the ratio of maximal over minimal EC50) was 46.03, indicating that all wild-type strains were sensitive to SYP-14288. To examine the risk of fungicide resistance, 20 SYP-14288-resistant mutants were generated on agar plates amended with SYP-14288. Eighteen mutants remained resistant after 10 transfers, and their fitness was significantly different from the parental strain. All of the mutants grew more slowly but showed high virulence to rice plants, though lower than the parental strain. A cross-resistance assay demonstrated that there was a positive correlation between SYP-14288 and fungicides having or not having the same mode of action with SYP-14288, including fluazinam, fentin chloride, fludioxonil, difenoconazole, cyazofamid, chlorothalonil, and 2,4-dinitrophen. This result showed a multidrug resistance induced by SYP-14288, which could be a concern in increasing the spectrum of resistance in R. solani to commonly used fungicides.


Assuntos
Fungicidas Industriais/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Doenças das Plantas , Rhizoctonia/efeitos dos fármacos
7.
Plant Dis ; 104(10): 2704-2712, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32716274

RESUMO

Soybean rust (SBR), caused by the fungus Phakopsora pachyrhizi, is the most damaging disease of soybean in Brazil. Effective management is achieved by means of calendar-timed sprays of fungicide mixtures, which do not explicitly consider weather-associated disease risk. Two rain-based action thresholds of disease severity values (DSV50 and DSV80) were proposed and compared with two leaf wetness duration-temperature thresholds of daily values of infection probability (DVIP6 and DVIP9) and with a calendar program, with regard to performance and profitability. An unsprayed check treatment plot was included for calculating relative control. Disease severity and yield data were obtained from 29 experiments conducted at six sites across four states in Brazil during the 2012-13, 2014-15, and 2015-16 growing seasons, which represented different growing regions and climatic conditions. The less conservative rainfall action threshold (DSV80) resulted in fewer fungicide sprays compared with the other treatments, and the more conservative one (DSV50) resulted in fewer sprays than the DVIP thresholds. Yield was generally higher with the increase in spray number, but the economic analysis showed no significant differences in the risk of not offsetting the costs of fungicide sprays regardless of the system. Therefore, based on the simplicity and the profitability of the rain-based model, the system is a good candidate for incorporating into the management of SBR in soybean production fields in Brazil.


Assuntos
Fungicidas Industriais/farmacologia , Soja , Brasil , Doenças das Plantas/prevenção & controle , Chuva
8.
Plant Dis ; 104(10): 2696-2703, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32729795

RESUMO

In present study, the morphological and physiological characteristics of Sclerotinia sclerotiorum (Lib.) de Bary to a novel succinate dehydrogenase inhibitor (SDHI) fungicide penthiopyrad has been reported. The baseline sensitivity of S. sclerotiorum to penthiopyrad was determined using 119 strains by inhibition of mycelial growth. The median effective concentration (EC50) values for penthiopyrad ranged from 0.0096 to 0.2606 µg/ml, and the mean value was 0.0578 (±0.0626) µg/ml. After 1 µg/ml penthiopyrad treatment, mycelia of S. sclerotiorum strains showed increased apical branching and were denser compared with control, and cell membrane permeability significantly increased. In addition, glycerol content, oxalic acid (OA), and exopolysaccharide (EPS) content decreased markedly and mycelial respiration was distinctly inhibited. The number and dry weight of sclerotia significantly decreased after being treated with 2 µg/ml penthiopyrad. Penthiopyrad exhibited both protective and curative activity on the detached rapeseed leaves. Importantly, the above results will provide us more information on penthiopyrad for management of diseases caused by S. sclerotiorum and increase our understanding of action of penthiopyrad against S. sclerotiorum.


Assuntos
Ascomicetos , Fungicidas Industriais/farmacologia , Pirazóis , Succinato Desidrogenase , Ácido Succínico , Tiofenos
9.
PLoS One ; 15(6): e0235568, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32598376

RESUMO

Filamentous fungi belonging to the genus Fusarium are notorious plant-pathogens that infect, damage and contaminate a wide variety of important crops. Phenamacril is the first member of a novel class of single-site acting cyanoacrylate fungicides which has proven highly effective against important members of the genus Fusarium. However, the recent emergence of field-resistant strains exhibiting qualitative resistance poses a major obstacle for the continued use of phenamacril. In this study, we synthesized novel cyanoacrylate compounds based on the phenamacril-scaffold to test their growth-inhibitory potential against wild-type Fusarium and phenamacril-resistant strains. Our findings show that most chemical modifications to the phenamacril-scaffold are associated with almost complete loss of fungicidal activity and in vitro inhibition of myosin motor domain ATPase activity.


Assuntos
Cianoacrilatos/farmacologia , Farmacorresistência Fúngica/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Fusarium/crescimento & desenvolvimento , Fusarium/efeitos dos fármacos
10.
PLoS One ; 15(6): e0234390, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32525917

RESUMO

Fungicide use in the United States to manage soybean diseases has increased in recent years. The ability of fungicides to reduce disease-associated yield losses varies greatly depending on multiple factors. Nonetheless, historical data are useful to understand the broad sense and long-term trends related to fungicide use practices. In the current study, the relationship between estimated soybean yield losses due to selected foliar diseases and foliar fungicide use was investigated using annual data from 28 soybean growing states over the period of 2005 to 2015. For national and regional (southern and northern United States) scale data, mixed effects modeling was performed considering fungicide use as a fixed and state and year as random factors to generate generalized R2 values for marginal (R2GLMM(m); contains only fixed effects) and conditional (R2GLMM(c); contains fixed and random effects) models. Similar analyses were performed considering soybean production data to see how fungicide use affected production. Analyses at both national and regional scales showed that R2GLMM(m) values were significantly smaller compared to R2GLMM(c) values. The large difference between R2 values for conditional and marginal models indicated that the variation of yield loss as well as production were predominantly explained by the state and year rather than the fungicide use, revealing the general lack of fit between fungicide use and yield loss/production at national and regional scales. Therefore, regression models were fitted across states and years to examine their importance in combination with fungicide use on yield loss or yield. In the majority of cases, the relationship was nonsignificant. However, the relationship between soybean yield and fungicide use was significant and positive for majority of the years in the study. Results suggest that foliar fungicides conferred yield benefits in most of the years in the study. Furthermore, the year-dependent usefulness of foliar fungicides in mitigating soybean yield losses suggested the possible influence of temporally fluctuating abiotic factors on the effectiveness of foliar fungicides and/or target disease occurrence and associated loss magnitudes.


Assuntos
Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Soja/crescimento & desenvolvimento , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Fungos/efeitos dos fármacos , Fungos/patogenicidade , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/provisão & distribução , Modelos Biológicos , Doenças das Plantas/microbiologia , Folhas de Planta/efeitos dos fármacos , Soja/efeitos dos fármacos , Soja/microbiologia , Análise Espaço-Temporal , Estados Unidos
11.
Plant Dis ; 104(8): 2168-2173, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32526154

RESUMO

Succinate dehydrogenase inhibitor (SDHI) fungicides are currently the most frequently used fungicides for controlling gray mold. However, isolates of Botrytis cinerea resistant to SDHI fungicides have emerged in the field. Pydiflumetofen is a new SDHI fungicide that can control a variety of fungal diseases, but its efficacy against gray mold and whether the activity of pydiflumetofen is affected by the current SDHI-resistant isolates is currently unknown. The sensitivity of 291 single-spore B. cinerea isolates collected from 2017 to 2019 to pydiflumetofen was determined by spore germination inhibition assays. The mean EC50 value (fungicide concentration resulting in a 50% inhibition compared with that of the control) of pydiflumetofen was 0.06 ± 0.01, 0.07 ± 0.02, and 0.05 ± 0.02 mg/liter in 2017, 2018, and 2019, respectively. There was no significant difference in the sensitivity of B. cinerea to pydiflumetofen among the 3 years. Furthermore, pydiflumetofen at 300 mg/liter effectively controlled gray mold on cucumber leaves (80.9%), and its efficacy was superior to that of boscalid at 400 mg/liter (42.7%). The isolates carrying P225F, N230I, H272Y, and H272R mutations in the SdhB subunit were associated with the less sensitivity of B. cinerea to SDHI fungicides. After establishing the baseline sensitivity of B. cinerea to pydiflumetofen (EC50 of 0.03 ± 0.003 mg/liter), we found that the P225F and H272Y mutant isolates showed low to moderate levels of resistance to pydiflumetofen, and the H272R and N230I mutant isolates showed low levels of resistance. The reduced sensitivity to pydiflumetofen resulted from the positive correlation of pydiflumetofen with the other four SDHI fungicides (i.e., boscalid, fluopyram, isopyrazam, and benzovindiflupyr). These results suggest that pydiflumetofen provides effective control for the management of gray mold but must be used with caution.


Assuntos
Botrytis , Fungicidas Industriais/farmacologia , Farmacorresistência Fúngica/efeitos dos fármacos , Doenças das Plantas , Succinato Desidrogenase , Ácido Succínico
12.
Arch Microbiol ; 202(9): 2391-2400, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32588084

RESUMO

An amplicon metagenomic approach based on the ITS1 region of fungal rDNA was employed to identify the composition of fungal communities associated with diseases of pear fruits during postharvest storage. The sampled fruits were harvested at an orchard using routine management practices involving treatments with various chemical fungicides and were transferred to a storage packinghouse. Effective tags of reading sequences clustered into 53 OTUs whereas Ascomycota was the dominant phylum (83.4%) followed by Basidiomycota (15.8%). Our results revealed that four genera, Penicillium, Rhodotorula, Alternaria and Cladosporium were the most abundant representing 59-95% of the relative abundance per sample. The interruption of chemical treatments during the last month before harvest altered the structure of the fungal community of fruits among untreated and treated samples, mainly in cases of relative abundance of Penicillium and Rhodotorula genera. We hypothesize that various antagonistic interactions might occur on fruit surfaces among the detected fungal genera whose relative abundances were affected by fungicide treatments. Interestingly, some common pre- and postharvest pear fungal pathogens were either less present (such as Moniliana), or undetected (such as Aspergillus, Venturia and Septoria) in untreated and treated samples.


Assuntos
Microbiologia de Alimentos , Frutas/microbiologia , Fungos , Metagenômica , Micobioma , Pyrus/microbiologia , Fungos/classificação , Fungos/efeitos dos fármacos , Fungos/genética , Fungicidas Industriais/farmacologia , Micobioma/efeitos dos fármacos , Micobioma/genética
13.
Food Chem ; 326: 126997, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32422511

RESUMO

The increased demand for pesticide-free foods has also increased the search for healthier and environmentally friendly alternatives in agriculture. Essential oils are known to possess natural antifungal properties, becoming a reliable alternative for commercial fungicides, especially for postharvest decay control. However, essential oils are volatile and photodegradable, which reduces their long-term activities. This work presents the development of a lemongrass essential oil-containing poly(lactic acid) nanocapsules. They have shown in vitro antifungal activity against Colletotrichum acutatum and Colletotrichum gloeosporioides with a MIC dosage of 0.1% (v/v) for both phytopathogens. In the in vivo assay with postharvest apples, the ones treated with encapsulated essential oil showed bitter rot lesions three times smaller than the ones treated with non-encapsulated essential oil, or in comparison to the apples in positive control. The methodology led to stable nanocapsules with spherical morphology, a mean diameter of 96.4 nm, and with an encapsulation efficiency of 99%.


Assuntos
Antifúngicos/farmacologia , Colletotrichum/efeitos dos fármacos , Cymbopogon/química , Fungicidas Industriais/farmacologia , Nanocápsulas/química , Óleos Voláteis/química , Poliésteres/farmacologia , Malus/efeitos dos fármacos , Malus/microbiologia , Poliésteres/química
14.
PLoS One ; 15(5): e0233916, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470037

RESUMO

The olive tree (Olea europaea L.) is the most important oil-producing crop of the Mediterranean basin. However, although plant protection measures are regularly applied, disease outbreaks represent an obstacle towards the further development of the sector. Therefore, there is an urge for the improvement of plant protection strategies based on information acquired by the implementation of advanced methodologies. Recently, heavy fungal infections of olive fruits have been recorded in major olive-producing areas of Greece causing devastating yield losses. Thus, initially, we have undertaken the task to identify their causal agent(s) and assess their pathogenicity and sensitivity to fungicides. The disease was identified as the olive anthracnose, and although Colletotrichum gloeosporioides and Colletotrichum acutatum species complexes are the two major causes, the obtained results confirmed that in Southern Greece the latter is the main causal agent. The obtained isolates were grouped into eight morphotypes based on their phenotypes, which differ in their sensitivities to fungicides and pathogenicity. The triazoles difenoconazole and tebuconazole were more toxic than the strobilurins being tested. Furthermore, a GC/EI/MS metabolomics model was developed for the robust chemotaxonomy of the isolates and the dissection of differences between their endo-metabolomes, which could explain the obtained phenotypes. The corresponding metabolites-biomarkers for the discrimination between morphotypes were discovered, with the most important ones being the amino acids L-tyrosine, L-phenylalanine, and L-proline, the disaccharide α,α-trehalose, and the phytotoxic pathogenesis-related metabolite hydroxyphenylacetate. These metabolites play important roles in fungal metabolism, pathogenesis, and stress responses. The study adds critical information that could be further exploited to combat olive anthracnose through its monitoring and the design of improved, customized plant protection strategies. Also, results suggest the necessity for the comprehensive mapping of the C. acutatum species complex morphotypes in order to avoid issues such as the development of fungicide-resistant genotypes.


Assuntos
Colletotrichum/fisiologia , Olea/microbiologia , Doenças das Plantas/prevenção & controle , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Colletotrichum/isolamento & purificação , Flores/microbiologia , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Grécia , Metabolômica , Azeite de Oliva , Folhas de Planta/microbiologia , Especificidade da Espécie , Virulência/efeitos dos fármacos
15.
Phytopathology ; 110(10): 1620-1622, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32378452

RESUMO

Black Sigatoka disease, caused by the fungus Pseudocercospora fijiensis, is one of the most devastating diseases of banana around the world. Fungicide applications are the primary tool used to manage black Sigatoka, but fungicide resistance in P. fijiensis, as in other fungal pathogens, is one of the major limitations in the efficient management and prevention of this disease. In the current study, we present the draft genome of P. fijiensis strain IIL-20, the first genomic sequence published from a strain of this fungus isolated in North America. Bioinformatic analysis showed putative genes involved in fungus virulence and fungicide resistance. These findings may lead us to a better understanding of the molecular pathogenesis of this fungal pathogen and also to the discovery of the mechanisms conferring fungicide resistance.


Assuntos
Ascomicetos/genética , Fungicidas Industriais/farmacologia , Musa , América do Norte , Doenças das Plantas
16.
Environ Sci Pollut Res Int ; 27(16): 20335-20343, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32242316

RESUMO

Imazalil (IMZ), a fungicide containing imidazole group, is extensively used for the prevention and treatment of fungal diseases in plants. Current study was performed to examine cyto-genotoxic potential of IMZ on Allium cepa roots by following Allium ana-telophase and single cell gel electrophoresis (comet) assays. The concentration which reduced the growth of the root tips of IMZ by 50% compared to the negative control group (EC50) was found to be 1 µg/mL by Allium root growth inhibition test. 0.5, 1, and 2 µg/mL concentrations of IMZ were exposed to Allium roots for intervals of 24, 48, 72, and 96 h. 10 µg/mL of methyl methane sulfonate (MMS) and distilled water were used as control groups, both positive and negative. Statistical analysis was performed by using one-way ANOVA with Duncan's multiple comparison tests at p ≤ 0.05 and Pearson correlation test at p = 0.01. IMZ showed cytotoxic effect by statistically decreasing root growth and mitotic index (MI) and also genotoxic effect by statistically increasing chromosomal aberrations (CAs) and DNA damage compared to the negative control group. With these cyto-genotoxic effects, it should be used carefully and further cyto-genotoxic mechanisms should be investigated along with other toxicity tests.


Assuntos
Fungicidas Industriais/farmacologia , Cebolas/genética , Aberrações Cromossômicas , Análise Citogenética , Dano ao DNA , Humanos , Imidazóis/farmacologia , Meristema/efeitos dos fármacos , Índice Mitótico , Raízes de Plantas/efeitos dos fármacos
17.
Nat Commun ; 11(1): 1608, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32231209

RESUMO

The emerging resistance of crop pathogens to fungicides poses a challenge to food security and compels discovery of new antifungal compounds. Here, we show that mono-alkyl lipophilic cations (MALCs) inhibit oxidative phosphorylation by affecting NADH oxidation in the plant pathogens Zymoseptoria tritici, Ustilago maydis and Magnaporthe oryzae. One of these MALCs, consisting of a dimethylsulfonium moiety and a long alkyl chain (C18-SMe2+), also induces production of reactive oxygen species at the level of respiratory complex I, thus triggering fungal apoptosis. In addition, C18-SMe2+ activates innate plant defense. This multiple activity effectively protects cereals against Septoria tritici blotch and rice blast disease. C18-SMe2+ has low toxicity in Daphnia magna, and is not mutagenic or phytotoxic. Thus, MALCs hold potential as effective and non-toxic crop fungicides.


Assuntos
Cátions/farmacologia , Produtos Agrícolas/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Substâncias Protetoras/farmacologia , Animais , Ascomicetos/efeitos dos fármacos , Cátions/química , Daphnia/efeitos dos fármacos , Descoberta de Drogas , Grão Comestível/microbiologia , Fibroblastos/efeitos dos fármacos , Fungicidas Industriais/química , Humanos , Mitocôndrias/efeitos dos fármacos , Oryza/microbiologia , Doenças das Plantas/microbiologia , Substâncias Protetoras/química , Triticum/microbiologia , Ustilago/efeitos dos fármacos
18.
Arch Microbiol ; 202(6): 1459-1467, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32189017

RESUMO

Sunflower is one of the most economically important oil crops. Recently, sunflower anthracnose caused by Colletotrichum destructivum was reported and suggested to be a potential threat to the quality of oil and edible seeds derived from sunflower in the field and even on the ornamentals in the residential gardens. Colletotrichum destructivum, as the causal agent of sunflower anthracnose, has been rarely studied. In this study, the vegetative growth and sporulation of this fungal species were investigated by assessing the requirements of nutrition and other environmental conditions, such as temperature, ambient pH, and lightness regime. Additionally, the sensitivity of C. destructivum to several fungicides was assessed. The results will provide a baseline for better understanding of the biology and etiology of C. destructivum. This study will be the first reference for a sustainable management strategy according to the occurrence and prevalence of the sunflower anthracnose.


Assuntos
Colletotrichum/crescimento & desenvolvimento , Fungicidas Industriais/farmacologia , Helianthus/microbiologia , Doenças das Plantas/microbiologia , Esporos Fúngicos/crescimento & desenvolvimento , Colletotrichum/classificação , Colletotrichum/efeitos dos fármacos , Colletotrichum/isolamento & purificação
19.
PLoS One ; 15(3): e0230254, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163490

RESUMO

Grape downy mildew (GDM) is a major disease of grapevine that has an impact on both the yields of the vines and the quality of the harvested fruits. The disease is currently controlled by repetitive fungicide treatments throughout the season, especially in the Bordeaux vineyards where the average number of fungicide treatments against GDM was equal to 10.1 in 2013. Reducing the number of treatments is a major issue from both an environmental and a public health point of view. One solution would be to identify vineyards that are likely to be heavily attacked in spring and then apply fungicidal treatments only to these situations. In this perspective, we use here a dataset including 9 years of GDM observations to develop and compare several generalized linear models and machine learning algorithms predicting the probability of high incidence and severity in the Bordeaux region. The algorithms tested use the date of disease onset and/or average monthly temperatures and precipitation as input variables. The accuracy of the tested models and algorithms is assessed by year-by-year cross validation. LASSO, random forest and gradient boosting algorithms show better performance than generalized linear models. The date of onset of the disease has a greater influence on the accuracy of forecasts than weather inputs and, among weather inputs, precipitation has a greater influence than temperature. The best performing algorithm was selected to evaluate the impact of contrasted climate scenarios on GDM risk levels. Results show that risk of GDM at bunch closure decreases with reduced rainfall and increased temperatures in April-May. Our results also show that the use of fungicide treatment decision rules that take into account local characteristics would reduce the number of treatments against GDM in the Bordeaux vineyards compared to current practices by at least 50%.


Assuntos
Doenças das Plantas/microbiologia , Vitis/microbiologia , Algoritmos , Clima , Fazendas , Previsões/métodos , Fungos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Modelos Lineares , Aprendizado de Máquina , Oomicetos/efeitos dos fármacos , Peronospora/efeitos dos fármacos , Estações do Ano , Temperatura , Tempo (Meteorologia)
20.
PLoS Pathog ; 16(3): e1008323, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32163521

RESUMO

Fusarium is a genus of filamentous fungi that includes species that cause devastating diseases in major staple crops, such as wheat, maize, rice, and barley, resulting in severe yield losses and mycotoxin contamination of infected grains. Phenamacril is a novel fungicide that is considered environmentally benign due to its exceptional specificity; it inhibits the ATPase activity of the sole class I myosin of only a subset of Fusarium species including the major plant pathogens F. graminearum, F. asiaticum and F. fujikuroi. To understand the underlying mechanisms of inhibition, species specificity, and resistance mutations, we have determined the crystal structure of phenamacril-bound F. graminearum myosin I. Phenamacril binds in the actin-binding cleft in a new allosteric pocket that contains the central residue of the regulatory Switch 2 loop and that is collapsed in the structure of a myosin with closed actin-binding cleft, suggesting that pocket occupancy blocks cleft closure. We have further identified a single, transferable phenamacril-binding residue found exclusively in phenamacril-sensitive myosins to confer phenamacril selectivity.


Assuntos
Cianoacrilatos/química , Proteínas Fúngicas/química , Fungicidas Industriais/química , Fusarium/enzimologia , Miosina Tipo I/química , Cianoacrilatos/farmacologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fungicidas Industriais/farmacologia , Fusarium/química , Fusarium/efeitos dos fármacos , Fusarium/genética , Miosina Tipo I/genética , Miosina Tipo I/metabolismo , Doenças das Plantas/microbiologia , Triticum/microbiologia , Zea mays/microbiologia
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