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1.
Ecotoxicol Environ Saf ; 204: 111117, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32798753

RESUMO

Wood distillate (pyroligneous acid) can be successfully applied in agriculture to increase crop quality and productivity with a lower risk for the environment respect to synthetic chemical herbicides, pesticides or fertilizers. However, the effects of wood distillate on the environment and biota are still under investigation, depending on biological attributes of potentially influenced organisms. The potential toxicological effects of wood distillate on sensitive non-target organisms, lichens and mosses, are studied for the first time. The physiological parameters (chlorophyll a fluorescence emission FV/FM and PI(ABS), chlorophyll content, spectral reflectance, antioxidant power, and dehydrogenase activity) and eventual bioaccumulation of selected elements (As, Ba, Cd, Cr, Cu, Fe, Ni, Pb, Zn) were investigated in the lichen Xanthoria parietina and the moss Hypnum cupressiforme after short-term treatments over a range of wood distillate solutions (1:300, 1:500, 1:700) to detect potential early stress responses. Overall, the lichen did not show changes after the treatments, while in the moss wood distillate caused only modest alterations in FV/FM and PI(ABS) and progressive increasing of antioxidant activity according to the dose supplied. The bioaccumulation of toxic elements was low and did not show any pattern of uptake with increasing concentrations of wood distillate.


Assuntos
Briófitas/efeitos dos fármacos , Herbicidas/toxicidade , Líquens/efeitos dos fármacos , Terpenos/toxicidade , Poluentes Atmosféricos/análise , Ascomicetos/efeitos dos fármacos , Briófitas/química , Bryopsida , Clorofila/farmacologia , Clorofila A , Biomarcadores Ambientais , Monitoramento Ambiental/métodos , Madeira/química
2.
PLoS One ; 15(8): e0235355, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817671

RESUMO

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


Assuntos
Ascomicetos/patogenicidade , Nanopartículas Metálicas/química , Phaseolus/microbiologia , Tolerância ao Sal , Ascomicetos/efeitos dos fármacos , Ascomicetos/metabolismo , Quitina Sintase/genética , Quitina Sintase/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Nanopartículas Metálicas/microbiologia , Phaseolus/metabolismo , Simbiose , Titânio/química , Titânio/farmacologia
3.
PLoS One ; 15(8): e0236822, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764772

RESUMO

Various marine fungi have been shown to produce interesting, bioactive compounds, but scaling up the production of these compounds can be challenging, particularly because little is generally known about how the producing organisms grow. Here we assessed the suitability of using 100-well BioScreen plates or 96-well plates incubated in a robot hotel to cultivate eight filamentous marine fungi, six sporulating and two non-sporulating, to obtain data on growth and substrate (glucose, xylose, galactose or glycerol) utilisation in a high throughput manner. All eight fungi grew in both cultivation systems, but growth was more variable and with more noise in the data in the Cytomat plate hotel than in the BioScreen. Specific growth rates between 0.01 (no added substrate) and 0.07 h-1 were measured for strains growing in the BioScreen and between 0.01 and 0.27 h-1 for strains in the plate hotel. Three strains, Dendryphiella salina LF304, Penicillium chrysogenum KF657 and Penicillium pinophilum LF458, consistently had higher specific growth rates on glucose and xylose in the plate hotel than in the BioScreen, but otherwise results were similar in the two systems. However, because of the noise in data from the plate hotel, the data obtained from it could only be used to distinguish between substrates which did or did not support growth, whereas data from BioScreen also provided information on substrate preference. Glucose was the preferred substrate for all strains, followed by xylose and galactose. Five strains also grew on glycerol. Therefore it was important to minimise the amount of glycerol introduced with the inoculum to avoid misinterpreting the results for growth on poor substrates. We concluded that both systems could provide physiological data with filamentous fungi, provided sufficient replicates are included in the measurements.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Penicillium/crescimento & desenvolvimento , Água do Mar/microbiologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/isolamento & purificação , Meios de Cultura/química , Meios de Cultura/farmacologia , Glucose/farmacologia , Glicerol/farmacologia , Penicillium/efeitos dos fármacos , Penicillium/isolamento & purificação , Xilose/farmacologia
4.
Int J Food Microbiol ; 331: 108694, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32521373

RESUMO

This study evaluated if coatings with chitosan (Chi) and phenolic-rich extract from acerola (Malpighia emarginata D.C., PEA) or jabuticaba (Plinia jaboticaba (Vell.) Berg, PEJ) processing by-products are effective to control the development of rot caused by Lasiodiplodia pseudotheobromae, L. viticola, L. euphorbicola, L. theobromae and L. hormozganensis in papaya (Carica papaya L.) fruit. Effects of formulated coatings on some physicochemical parameters indicative of postharvest quality of papaya were investigated. Twenty-six different phenolics were found in PEA and PEJ, including flavonoids, stilbenes, tannins and phenolic acids. Chi (1-5 mg/mL), PEA and PEJ (25-100 mg/mL) separately caused mycelial growth inhibition on all isolates. Combinations of Chi (3 and 4 mg/mL) and PEA (50 and 75 mg/mL) or PEJ (75 and 100 mg/mL) had additive interactions. Coatings with Chi (4 mg/mL) and PEA (50 or 75 mg/mL) or PEA (75 or 100 mg/mL) inhibited rot development in papaya fruit infected with Lasiodiplodia isolates during 8 days of room temperature storage. Coatings with 4 mg/mL Chi and 75 mg/mL PEA or 100 mg/mL PEJ were the most effective to control rot development. These coatings did not affect negatively physicochemical parameters indicative of postharvest quality of papaya fruit during storage. Coatings with combined Chi and PEA or PEJ could be novel strategies to control postharvest rot caused by Lasiodiplodia in papaya fruit.


Assuntos
Carica/microbiologia , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Frutas/microbiologia , Malpighiaceae/química , Myrtaceae/química , Extratos Vegetais/farmacologia , Ascomicetos/efeitos dos fármacos , Quitosana/farmacologia , Fenóis/farmacologia
5.
PLoS One ; 15(5): e0229630, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32401759

RESUMO

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


Assuntos
Antifúngicos/farmacologia , Cromoblastomicose/tratamento farmacológico , Sinergismo Farmacológico , Fungos/patogenicidade , Acetatos/farmacologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/patogenicidade , Auranofina/farmacologia , Compostos de Bifenilo/farmacologia , Cromoblastomicose/microbiologia , Cromoblastomicose/patologia , Dioxolanos/farmacologia , Exophiala/efeitos dos fármacos , Exophiala/patogenicidade , Fungos/efeitos dos fármacos , Humanos , Iminas/farmacologia , Iodoquinol/farmacologia , Pirimidinas/farmacologia , Estrobilurinas/farmacologia , Triazóis/farmacologia
6.
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
7.
Food Chem ; 321: 126701, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32283502

RESUMO

The antifungal activity of a library of twenty-four aromatic methoximes was examined against five representative postharvest phytopathogenic fungi. The panel included Penicillium digitatum, Penicillium italicum, Rhizopus stolonifer, Botrytis cinerea and Monilinia fructicola, all of which cause relevant economic losses worldwide as a result of affecting harvested fruits. The minimum inhibitory concentrations and minimum fungicidal concentrations of each compound were defined and the main structure-activity relationships were determined. Although other congeners were more potent, drug likeliness considerations pointed to the methoxime derived from 2,4-dihydroxypropiophenone as the compound with the most suitable profile. The morphology of the colonies of the fungal strains treated with the methoxime was examined microscopically and the compound was also tested in freshly harvested peaches and oranges, exhibiting promising control profiles in both fruits, similar to those of the commercial agents Imazalil and Carbendazim.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Frutas/microbiologia , Oximas/química , Ascomicetos/efeitos dos fármacos , Botrytis/efeitos dos fármacos , Citrus sinensis/efeitos dos fármacos , Citrus sinensis/microbiologia , Frutas/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Oximas/farmacologia , Penicillium/efeitos dos fármacos , Prunus persica/efeitos dos fármacos , Prunus persica/microbiologia , Rhizopus/efeitos dos fármacos , Relação Estrutura-Atividade
8.
Microbiol Res ; 236: 126436, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32179388

RESUMO

Trichoderma longibrachiatum EF5 is an endophytic fungal antagonist of rice. It is used for the control of soil-borne fungal pathogens-Sclerotium rolfsii and Macrophomina phaseolina. We demonstrate that T. longibrachiatum EF5 inhibits the growth of these pathogens on direct interaction as well as via the production of the microbial volatile organic compounds (mVOCs). The mVOCs reduced mycelial growth and inhibited the production of sclerotia by altering the mycelial structure. We profiled 138 mVOCs, when T. longibrachiatum EF5 interacted with the two pathogens. During these interactions, several compounds are up- or downregulated by T. longibrachiatum EF5, including longifolene, caryophyllene,1-Butanol 2-methyl, cedrene, and cuprenene. These compounds are involved in the biosynthetic pathways of the sesquiterpenoid and alkane, and the degradation pathway of trimethylamine. We provide an insight into the multiple modes by which T. longibrachiatum EF5 exerts antagonistic actions, such as hyperparasitism, competitions, and antibiosis via mVOCs. In contrast to their antimicrobial properties, these metabolites could also promote plant growth.


Assuntos
Agaricales/efeitos dos fármacos , Antibiose , Ascomicetos/efeitos dos fármacos , Trichoderma/metabolismo , Compostos Orgânicos Voláteis/farmacologia , Agaricales/crescimento & desenvolvimento , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico , Interações Microbianas , Doenças das Plantas/microbiologia , Microbiologia do Solo , Compostos Orgânicos Voláteis/química
9.
PLoS One ; 15(3): e0230362, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32176712

RESUMO

Fungi in the genus Cercospora cause crop losses world-wide on many crop species. The wide host range and success of these pathogens has been attributed to the production of a photoactivated toxin, cercosporin. We engineered tobacco for resistance to Cercospora nicotianae utilizing two strategies: 1) transformation with cercosporin autoresistance genes isolated from the fungus, and 2) transformation with constructs to silence the production of cercosporin during disease development. Three C. nicotianae cercosporin autoresistance genes were tested: ATR1 and CFP, encoding an ABC and an MFS transporter, respectively, and 71cR, which encodes a hypothetical protein. Resistance to the pathogen was identified in transgenic lines expressing ATR1 and 71cR, but not in lines transformed with CFP. Silencing of the CTB1 polyketide synthase and to a lesser extent the CTB8 pathway regulator in the cercosporin biosynthetic pathway also led to the recovery of resistant lines. All lines tested expressed the transgenes, and a direct correlation between the level of transgene expression and disease resistance was not identified in any line. Resistance was also not correlated with the degree of silencing in the CTB1 and CTB8 silenced lines. We conclude that expression of fungal cercosporin autoresistance genes as well as silencing of the cercosporin pathway are both effective strategies for engineering resistance to Cercospora diseases where cercosporin plays a critical role.


Assuntos
Ascomicetos/genética , Resistência à Doença/genética , Farmacorresistência Fúngica/genética , Inativação Gênica , Genes Fúngicos , Engenharia Genética , Perileno/análogos & derivados , Tabaco/microbiologia , Ascomicetos/efeitos dos fármacos , Resistência à Doença/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Inativação Gênica/efeitos dos fármacos , Perileno/farmacologia , Plantas Geneticamente Modificadas , Transformação Genética , Transgenes
10.
J Mycol Med ; 30(1): 100920, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31892498

RESUMO

Onychomycosis is considered a fungal nail infection caused mainly by dermatophytes, yeasts and non-dermatophyte molds including dematiaceous fungi. Onychomycosis caused by non-dermatophyte molds is a health problem in the medical environment as the patients frequently return to outpatient clinics seeking new therapeutic modalities. Here, we report the first case of onychomycosis caused by a black fungus, Neoscytalidium novaehollandiae, in the right hand finger nail of a 52-year-old Iranian female with no history of immunodeficiency and underlying disease. The pattern of nail involvement was recognized as total dystrophic onychomycosis. Examination of nail scrapings with potassium hydroxide revealed brown, septate and branching sub-hyaline to dark-colored hyphae. The black fungus isolated in culture was identified as Neoscytalidium novaehollandiae by molecular analysis. The patient received oral terbinafine plus ciclopirox nail lacquer twice a week and began responding to the treatment three months after initial antifungal therapy. Additional four weeks' use of terbinafine plus ciclopirox nail lacquer completely resolved the clinical manifestations of onychomycosis. After four months, both microscopy and culture were negative.


Assuntos
Ascomicetos , Dermatoses da Mão/microbiologia , Onicomicose/microbiologia , Antifúngicos/uso terapêutico , Ascomicetos/efeitos dos fármacos , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Feminino , Dermatoses da Mão/diagnóstico , Dermatoses da Mão/tratamento farmacológico , Humanos , Imunocompetência , Irã (Geográfico) , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Técnicas de Diagnóstico Molecular , Técnicas de Tipagem Micológica/métodos , Onicomicose/diagnóstico , Onicomicose/tratamento farmacológico
11.
Plant Dis ; 104(1): 129-136, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31747352

RESUMO

Gummy stem blight, caused by Stagonosporopsis spp., is a major disease of cucurbits in the United States and China that is managed primarily through the use of fungicides. The objective of this study was to monitor and compare the recent fungicide resistance profiles of Stagonosporopsis spp. in Florida open-field and East China protected-structure production systems. Isolates of Stagonosporopsis spp. were evaluated for sensitivity to the commonly used fungicides azoxystrobin, boscalid, tebuconazole, and thiophanate-methyl at discriminatory rates of 0.096, 0.034, 0.128, and 100 mg/liter, respectively. Isolates were collected from Jiangsu, Jiangxi, Zhejiang, and Anhui provinces in China (n = 69), 12 counties in Florida (n = 89), and one county in Georgia (n = 6). More than 50% of isolates from Florida and East China were resistant to thiophanate-methyl. Boscalid resistance was detected in both isolate collections but was two times more frequent in China. Resistance to azoxystrobin was detected in 66% of isolates in Florida but only 7% in China. Tebuconazole was effective in controlling the mycelia growth of Stagonosporopsis spp. in both collections. The results indicate that both production systems currently face similar challenges related to the development of fungicide resistance in Stagonosporopsis spp. However, the resistance profiles are unique for both production systems.


Assuntos
Agricultura , Ascomicetos , Cucurbita , Farmacorresistência Fúngica , Fungicidas Industriais , Agricultura/tendências , Ascomicetos/efeitos dos fármacos , China , Cucurbita/microbiologia , Florida , Fungicidas Industriais/farmacologia , Georgia , Doenças das Plantas/microbiologia
12.
Environ Sci Pollut Res Int ; 27(1): 597-606, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31808087

RESUMO

Macrophomina phaseolina (Tassi) Goid. is primarily a phytopathogen but also exhibits potential to cause infection in human being due to its aggressive and robust nature. Adaptation potential in M. phaseolina was assessed after exposing to heavy metal copper through analysing macro- and microscopic as well as physiological attributes. Considerable modifications were observed in morphology with an increase in concentrations (25, 75, and 100 ppm) of copper as compared with control. Total content of protein and activities of the antioxidant enzymes were affected differently at different copper concentrations. The fungal biomass, metal accumulation, metal uptake efficiency, and bioaccumulation factors were decreased due to the increase in copper concentrations. Fourier transformed infrared spectroscopic assessment showed hydroxyl, carboxyl, and amine groups as major metal accumulation sites. It is concluded that Cu-based fungicides can manage this pathogen but excessive application may accumulate in the plant that will transfer along the food chain, reaching ultimately the human body.


Assuntos
Antioxidantes/metabolismo , Ascomicetos/fisiologia , Cobre/toxicidade , Poluentes Ambientais/toxicidade , Plantas/microbiologia , Ascomicetos/efeitos dos fármacos , Humanos
13.
Chem Biodivers ; 17(2): e1900570, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31778280

RESUMO

A series of sarisan analogs containing 1,3,4-oxadiazole moieties were synthesized by iodine-mediated oxidative cyclization and screened in vitro for their antifungal activities at 50 µg/mL against five phytopathogenic fungi such as Valsa mali, Curvularia lunata, Alternaria alternate, Fusarium solani and Fusarium graminearum. 1,3,4-Oxadiazole derivatives 7e, 7p, 7r, 7t and 7u exhibited potent and a broad spectrum of antifungal activities against at least three phytopathogenic fungi at the concentration of 50 µg/mL. Especially, compound 7r displayed more potent antifungal activities against five phytopathogenic fungi than the positive control hymexazol. The EC50 of 7r against V. mali, C. lunata and A. alternate were 12.6, 14.5 and 17.0 µg/mL, respectively. Additionally, some interesting results of structure-activity relationships (SARs) were also observed.


Assuntos
Antifúngicos/síntese química , Produtos Biológicos/síntese química , Dioxolanos/química , Desenho de Fármacos , Oxidiazóis/química , Alternaria/efeitos dos fármacos , Antifúngicos/farmacologia , Ascomicetos/efeitos dos fármacos , Produtos Biológicos/farmacologia , Dioxolanos/farmacologia , Fusarium/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade
14.
Plant Dis ; 104(1): 52-59, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31738691

RESUMO

In field trials in Iowa, we investigated the association of a fungicide applied at early pod set to the diversity and composition of foliar endophytic fungi in presenescent soybeans. The main purpose of our study was to determine whether fungicides affect the microbiome of soybean plants during the pod-fill reproductive stage. In a replicated experiment focused on the impact of a fungicide application including a quinone outside inhibitor (QoI) and a pyrazole-carboxamide spanning two growing seasons, healthy stems and leaves near the tops of soybean were sampled for endophytic fungi. The survey yielded 1,791 isolates belonging to 17 putative species, identified by morphology and sequence analysis of the ribosomal DNA internal transcribed spacer region. Taxa were grouped by genus into operational taxonomic units: Alternaria, Colletotrichum, and Diaporthe were the dominant genera isolated. Plant parts were analyzed separately using a multivariate community analysis of isolate counts per plant. The 14.3% fluxapyroxad and 28.6% pyraclostrobin fungicide spray significantly increased the proportion of Diaporthe isolates over no-spray controls, whereas the inverse occurred for foliar Alternaria isolates. In addition, seed harvested from fields with shorter-season varieties and sprayed with fungicide showed higher percentages of Diaporthe isolates than fields with no fungicide spray. In conclusion, soybean farmers may want to consider that the application of a QoI fungicide in the absence of disease pressure might adversely impact seed quality.


Assuntos
Alternaria , Ascomicetos , Endófitos , Fungicidas Industriais , Soja , Alternaria/efeitos dos fármacos , Ascomicetos/efeitos dos fármacos , Endófitos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Iowa , Soja/microbiologia , Especificidade da Espécie
15.
Environ Pollut ; 257: 113495, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31733958

RESUMO

Sclerotinia sclerotiorum (S. sclerotiorum) is a soil-borne pathogen causing serious damage to the yield of oilseed rape. Selenium (Se) acted as a beneficial element for plants, and also proved to inhibit the growth of plant pathogens. However, whether Se could reduce S. sclerotiorum infection in oilseed rape, the related mechanism is still unclear. In this study, proper Se levels (0.1 mg/kg and 0.5 mg/kg) applied in soil decreased the lesion diameter and incidence of S. sclerotiorum in rape leaves. Se enfeebled the decrease of net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr), and maintained leaf cell structure. Se enhanced the antioxidant system of leaves, as evidenced by the maintenance of mitochondrial function, reduction of reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content, and the improvement of antioxidant enzyme activities including catalase (CAT), polyphenol oxidase (PPO) and peroxidase (POD). The upregulated defense gene expressions (CHI, ESD1, NPR1 and PDF1.2) of leaves were also observed under Se treatments. Furthermore, metabolome analysis revealed that Se promoted the metabolism of energy and amino acids in leaves infected with S. sclerotiorum. These findings inferred that Se could act as a potential eco-fungicide to protect oilseed rape leaves from S. sclerotiorum attack. The result arising from this study not only introduces an ecological method to control S. sclerotiorum, but also provides a deep insight into microelement for plant protection.


Assuntos
Ascomicetos/efeitos dos fármacos , Brassica napus/microbiologia , Fungicidas Industriais/farmacologia , Selênio/farmacologia , Antioxidantes/metabolismo , Infecções , Doenças das Plantas/prevenção & controle , Folhas de Planta/efeitos dos fármacos , Solo
16.
Plant Dis ; 104(1): 168-178, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31697224

RESUMO

Apple scab, caused by Venturia inaequalis, is the most common fruit and foliar disease in commercial apple production worldwide. Early in the production season, preventative contact fungicide sprays are essential for protecting highly susceptible continuously unfolding and expanding young leaves. In South Africa, mancozeb is a key contact fungicide used for controlling apple scab early in the season. The current study developed deposition benchmarks indicative of the biological efficacy of mancozeb against apple scab, using a laboratory-based apple seedling model system. The model system employed a yellow fluorescent pigment that is known to be an effective tracer of mancozeb deposition. A concentration range of mancozeb (0.15 to 1 times the registered dosage) and fluorescent pigment concentrations was sprayed onto seedling leaves, which yielded various fluorescent particle coverage (FPC%) levels. Modeling of the FPC% values versus percent disease control yielded different benchmark values when disease quantification was conducted using two different methods. Thermal infrared imaging (TIRI) disease quantification resulted in a benchmark model where 0.40%, 0.79%, and 1.35 FPC% yielded 50, 75, and 90% apple scab control, respectively. These FPC% values were higher than the benchmarks (0.10, 0.20, and 0.34 FPC%, respectively) obtained with quantitative real-time PCR (qPCR) disease quantification. The qPCR benchmark model is recommended as a guideline for evaluating the efficacy of mancozeb sprays on leaves in apple orchards since the TIRI benchmark model underestimated disease control. The TIRI benchmark model yielded 68% disease control at the lowest mancozeb dosage, yet no visible lesion developed at this dosage. Both benchmark models showed that mancozeb yielded high levels of disease control at very low concentrations; for the qPCR benchmark model the FPC% value of the FPC90 (90% control) corresponded to 0.15 times that of the registered mancozeb concentration in South Africa, i.e., 85% lower than the registered dosage.


Assuntos
Ascomicetos , Malus , Maneb , Doenças das Plantas , Zineb , Ascomicetos/efeitos dos fármacos , Benchmarking , Malus/microbiologia , Maneb/química , Maneb/farmacologia , Doenças das Plantas/prevenção & controle , Folhas de Planta/microbiologia , África do Sul , Zineb/química , Zineb/farmacologia
17.
Food Chem ; 305: 125483, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31610420

RESUMO

Kiwifruit (Actinidia deliciosa cv. Jinkui) were treated with 0.1 mmol/L methyl jasmonate (MeJA) to investigate the effects on disease resistance to soft rot caused by Botryosphaeria dothidea. The results showed that MeJA treatment significantly reduced the diameter of lesions after inoculation with B. dothidea. This treatment significantly enhanced the activities of related antioxidant protective enzymes, defence-related enzymes including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO), chitinase (CHI), ß-1,3 glucanase (GLU) and increased the accumulation of total phenolic content, while the degree of membrane lipid peroxidation was reduced. MeJA treatment effectively enhanced gene expression of AcPOD, AcSOD, AcCHI and AcGLU. The results from this research suggest that MeJA treatment is a promising and safe strategy for controlling postharvest rot soft of kiwifruit.


Assuntos
Acetatos/farmacologia , Actinidia/microbiologia , Ascomicetos/efeitos dos fármacos , Ciclopentanos/farmacologia , Resistência à Doença/efeitos dos fármacos , Oxilipinas/farmacologia , Actinidia/química , Actinidia/metabolismo , Ascomicetos/fisiologia , Quitinases/genética , Quitinases/metabolismo , Frutas/química , Frutas/metabolismo , Frutas/microbiologia , Expressão Gênica/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Peroxidase/genética , Peroxidase/metabolismo , Fenóis/análise , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo
18.
Plant Biol (Stuttg) ; 22(1): 70-80, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31283085

RESUMO

The effects of elevated glutathione levels on defence responses to powdery mildew (Euoidium longipes) were investigated in a salicylic acid-deficient tobacco (Nicotiana tabacum cv. Xanthi NahG) and wild-type cv. Xanthi plants, where salicylic acid (SA) contents are normal. Aqueous solutions of reduced glutathione (GSH) and its synthetic precursor R-2-oxothiazolidine-4-carboxylic acid (OTC) were injected into leaves of tobacco plants 3 h before powdery mildew inoculation. SA-deficient NahG tobacco was hyper-susceptible to E. longipes, as judged by significantly more severe powdery mildew symptoms and enhanced pathogen accumulation. Strikingly, elevation of GSH levels in SA-deficient NahG tobacco restored susceptibility to E. longipes to the extent seen in wild-type plants (i.e. enhanced basal resistance). However, expression of the SA-mediated pathogenesis-related gene (NtPR-1a) did not increase significantly in GSH or OTC-pretreated and powdery mildew-inoculated NahG tobacco, suggesting that the induction of this PR gene may not be directly involved in the defence responses induced by GSH. Our results demonstrate that artificial elevation of glutathione content can significantly reduce susceptibility to powdery mildew in SA-deficient tobacco.


Assuntos
Ascomicetos , Resistência à Doença , Glutationa , Ácido Salicílico , Tabaco , Ascomicetos/efeitos dos fármacos , Ascomicetos/fisiologia , Resistência à Doença/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas , Glutationa/metabolismo , Glutationa/farmacologia , Plantas Geneticamente Modificadas/química , Plantas Geneticamente Modificadas/microbiologia , Tabaco/química , Tabaco/microbiologia
19.
World J Microbiol Biotechnol ; 36(1): 7, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31845300

RESUMO

Orange juice is a major agricultural product, and oranges are among the most widely sold fresh fruits in several countries. Citrus black spot (CBS), caused by the fungus Phyllosticta citricarpa, affects almost every species of citrus, causing a esthetic depreciation of the fruit and fruit drop, with consequent financial loss for its in natura commercialization. Fungicides are the major control measure for CBS, but have limited efficiency and high cost, and give rise to fungal strains resistant to these products. This work assayed the production of antifungal compounds by Bacillus spp. isolates and tested the potential of two isolates from B. subtilis (ACB-AP3 and ACB-83) for controlling CBS under field conditions with two previously untested orange varieties. A total of 15 isolates produced cell-free, thermostable or volatile compounds effective in suppressing P. citricarpa growth in vitro. It was possible to detect the production of two antibiotics (iturin and surfactin) by B. subtilis ACB-83. Additionally, B. subtilis isolates ACB-AP3 and ACB-83 displayed significant effects in controlling the disease under field conditions.


Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Ascomicetos/efeitos dos fármacos , Bacillus/isolamento & purificação , Bacillus/metabolismo , Citrus/microbiologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Frutas/microbiologia , Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Esporos Fúngicos
20.
PLoS Pathog ; 15(12): e1007780, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31860693

RESUMO

Succinate dehydrogenase inhibitor (SDHI) fungicides are widely used for the control of a broad range of fungal diseases. This has been the most rapidly expanding fungicide group in terms of new molecules discovered and introduced for agricultural use over the past fifteen years. A particular pattern of differential sensitivity (resistance) to the stretched heterocycle amide SDHIs (SHA-SDHIs), a subclass of chemically-related SDHIs, was observed in naïve Zymoseptoria tritici populations not previously exposed to these chemicals. Subclass-specific resistance was confirmed at the enzyme level but did not correlate with the genotypes of the succinate dehydrogenase (SDH) encoding genes. Mapping and characterization of the molecular mechanisms responsible for standing SHA-SDHI resistance in natural field isolates identified a gene paralog of SDHC, termed ZtSDHC3, which encodes for an alternative C subunit of succinate dehydrogenase, named alt-SDHC. Using reverse genetics, we showed that alt-SDHC associates with the three other SDH subunits, leading to a fully functional enzyme and that a unique Qp-site residue within the alt-SDHC protein confers SHA-SDHI resistance. Enzymatic assays, computational modelling and docking simulations for the two SQR enzymes (altC-SQR, WT_SQR) enabled us to describe enzyme-inhibitor interactions at an atomistic level and to propose rational explanations for differential potency and resistance across SHA-SDHIs. European Z. tritici populations displayed a presence (20-30%) / absence polymorphism of ZtSDHC3, as well as differences in ZtSDHC3 expression levels and splicing efficiency. These polymorphisms have a strong impact on SHA-SDHI resistance phenotypes. Characterization of the ZtSDHC3 promoter in European Z. tritici populations suggests that transposon insertions are associated with the strongest resistance phenotypes. These results establish that a dispensable paralogous gene determines SHA-SDHIs fungicide resistance in natural populations of Z. tritici. This study paves the way to an increased awareness of the role of fungicidal target paralogs in resistance to fungicides and demonstrates the paramount importance of population genomics in fungicide discovery.


Assuntos
Ascomicetos/genética , Farmacorresistência Fúngica/genética , Fungicidas Industriais , Succinato Desidrogenase/genética , Ascomicetos/efeitos dos fármacos , Ascomicetos/enzimologia , Doenças das Plantas/microbiologia
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