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1.
J Agric Food Chem ; 68(8): 2418-2425, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32011876

RESUMO

Two biosynthetically related new metabolites, eucalyptacid A (1) and eucalactam B (2), along with six known compounds (3-8), eugenitol (3), cytosporone C (4), 4-hydroxyphenethyl alcohol (5), 1-(4-hydroxyphenyl)ethane-1,2-diol (6), N-(2-hydroxy-2-phenylethyl)acetamide (7), and phomopene (8), were isolated from the solid rice cultures of the endophytic fungus Diaporthe eucalyptorum KY-9 that had been isolated from Melia azedarach. Also, two further new derivatives (2a, 2b) were prepared from 2. The structures were elucidated by exhaustive analysis of NMR and ESIMS data and chemical methods such as Marfey's protocol. Compound 1 was identified as a rare polyketide fatty acid, (8E)-3,5,11-trihydroxy-2,10,12-trimethyltetradecenoic acid, and 2 was determined to be the first cyclic depsipeptide containing the same fatty acid unit as 1 and a Gly-Gly-Thr tripeptide chain. Its N-terminal end is N-acylated by an 11-hydroxy fatty acid with a branch alkyl chain of 14:1. The 11-hydroxyl group connects to the carboxylic group of the C-terminal amino acid to form a 22-membered lactone ring. A hypothetical biosynthetic pathway for the new polyketides is proposed. The isolated compounds were assayed for their inhibition against four plant pathogenic fungi, Alternaria solani, Botrytis cinerea, Fusarium solani, and Gibberella saubinettii. Compounds 1, 4, 6, and 7 exhibited antifungal activities against Alternaria solani, with minimal inhibitory concentration (MIC) values from 6.25 to 50 µM. Thus, strain KY-9 represents an untapped source for the development of biological control agents to prevent the infection of pathogenic fungus A. solani.


Assuntos
Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Melia azedarach/microbiologia , Saccharomycetales/química , Alternaria/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/química , Fungicidas Industriais/isolamento & purificação , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Saccharomycetales/isolamento & purificação , Saccharomycetales/metabolismo
2.
J Agric Food Chem ; 68(8): 2306-2315, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31995378

RESUMO

Neocryptolepine is an alkaloid isolated from traditional African herbal medicine Cryptolepis sanguinolenta, and its broad spectrum of biological activities has been illuminated in past decades. In this study, neocryptolepine and its derivatives (1-49) were designed and synthesized from economical and readily available starting materials. Their structures were confirmed by proton nuclear magnetic resonance, carbon nuclear magnetic resonance, and mass spectrometry. The synthesized compounds were screened for their antifungal profile against six agriculturally important fungi Rhizoctonia solani, Botrytis cinerea (B. cinerea), Fusarium graminearum, Mycosphaerella melonis, Sclerotinia sclerotiorum, and Magnaporthe oryzae. The results of in vitro assay revealed that compounds 5, 21, 24, 35, 40, 45, and 47 presented remarkable antifungal activity against the fungi tested with EC50 values lower than 1 µg/mL. Significantly, compound 24 displayed the most effective inhibitory potency against B. cinerea (EC50 = 0.07 µg/mL), and the data from in vivo experiments revealed that compound 24 demonstrated comparable protective activity with the positive control boscalid. Preliminary mechanism studies indicated that compound 24 showed impressive spore germination inhibitory effectiveness and lower cytotoxicity than azoxystrobin, imparted on normal function of the cell membrane and cell wall, and arrested the normal function of the nucleus. Besides the excellent inhibitory activity against agriculturally important phytopathogenic fungi tested, the designed assemblage possesses several benefits with a high profile of variation in synthesized molecules, the ease of synthesis, and good cost-effectiveness of commercially available synthetic reagents, all of these have highlighted the potential worth of compound 24 as a new and highly efficient agricultural fungicide.


Assuntos
Antifúngicos/farmacologia , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Antifúngicos/síntese química , Antifúngicos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Estrutura Molecular , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimento , Relação Estrutura-Atividade
3.
Appl Microbiol Biotechnol ; 104(5): 2163-2178, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31980918

RESUMO

Tea tree oil (TTO) and its two characteristic components (terpinen-4-ol and 1,8-cineole) have been shown to inhibit Botrytis cinerea growth. In this study, we conducted a transcriptome analysis to determine the effects of TTO and its characteristic components, alone and in combination, against B. cinerea. Most differentially expressed genes (DEGs) from B. cinerea cells treated with terpinen-4-ol participated in the biosynthesis of secondary metabolites, and the metabolism of amino acids, carbohydrates, and lipids. All treatments containing terpinen-4-ol potentially induced mitochondrial dysfunction and oxidative stress. These were further confirmed by the decreased activities of several enzymes (e.g., succinate dehydrogenase (SDH), malate dehydrogenase (MDH), α-ketoglutarate dehydrogenase (α-KGDH), isocitrate dehydrogenase (ICDH)), the increased activities of certain enzymes (e.g., catalase (CAT), peroxidase (POD), superoxide dismutase (SOD)), and increased content of hydrogen peroxide (H2O2). 1,8-Cineole mainly affected DEGs involved in genetic information processing, resulting in cell death. This study provides insight into the molecular mechanism of B. cinerea inhibition by TTO, and explains the synergistic effect of terpinen-4-ol and 1,8-cineole on B. cinerea.


Assuntos
Antifúngicos/farmacologia , Botrytis/efeitos dos fármacos , Botrytis/genética , Óleo de Melaleuca/farmacologia , Antifúngicos/química , Botrytis/crescimento & desenvolvimento , Sinergismo Farmacológico , Eucaliptol/farmacologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Perfilação da Expressão Gênica , Peróxido de Hidrogênio/metabolismo , Óleo de Melaleuca/química , Terpenos/farmacologia , Transcriptoma/efeitos dos fármacos
4.
J Photochem Photobiol B ; 203: 111656, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31676121

RESUMO

Strawberries are one of the most common and important fruits in the world, widely investigated for their nutritional and nutraceutical properties. However, after the emergence of several outbreaks of foodborne diseases some concerns regarding the microbiological safety of fresh strawberries have increased in recent years. In this paper new insights, based on application of ZnO nanoparticles (NPs) as alternative to chemical fungicides in the fields for preharvest preservation of strawberries are presented. Antifungal activity of ZnO NPs was tested on main strawberry plant pathogen Botrytis cinerea. Obtained data indicated that used ZnO NPs (5 × 10-3 M) in the dark just insignificantly (12%) inhibited the radial growth of B. cinerea. But photoactivated ZnO NPs (5 × 10-3 M, 405 nm, 34 J/cm2) inhibited the growth of B. cinera by 80%. Real-time field experiments revelead, that spraying of ZnO NPs in the strawberry field in sunny day reduced Botrytis incidences by 43%, enhanced the crop production by 28.5% and stoped the spoilage of harvested fruits during storage by 8 days, if compare with control. No harm to crowns and leaves of strawberry plant have been found, however this treatment increased the growth of inflorescence (37.5%) and reduced the growth of runners (32.8%). For comparison, spraying of conventionqal chemical fungicide fenhexamid (FEN) reduced Botrytis incidences in the same level as ZnO NPs, increased the harvest by 21.9% and delayed the spoilage of fruits by 8 days. The presented results look highly promising, since ZnO NPs in the presence of sunlight, activated by UV and visible light can protect strawberry fruits from Botrytis infection more effectively than conventional fungicide fenhexamid. This treatment significantly increased crop production and reduced spoilage of strawberries. It looks like ZnO NPs have great potential in the future to replace chemical fungicides.


Assuntos
Fragaria/crescimento & desenvolvimento , Nanopartículas Metálicas/química , Luz Solar , Óxido de Zinco/química , Amidas/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Botrytis/efeitos dos fármacos , Botrytis/efeitos da radiação , Catálise , Proteção de Cultivos , Nanopartículas Metálicas/toxicidade , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
5.
Phytopathology ; 110(2): 327-335, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31502521

RESUMO

Succinate dehydrogenase inhibitors (SDHIs) are an essential group of fungicides for managing gray mold, caused by Botrytis cinerea, in numerous crops. Resistance to boscalid, an early-generation SDHI, is widespread worldwide and was linked to mutations in the iron-sulfur protein encoding the SdhB subunit of the SDH complex. Herein, we report on four simultaneous dependent mutations at codons 85 (G85A), 93 (I93V), 158 (M158V), and 168 (V168I) of the membrane-anchored SdhC subunit of B. cinerea. Isolates without and with mutations in SdhC were referred to as C- and C+ genotypes, respectively. The C+ genotype was found in all the five surveyed hosts from different U.S. regions but its frequency was higher, 25 to 40%, in the tree fruit isolates compared with 12 to 25% in the small fruit populations. The four SdhC mutations were found in isolates without mutations in SdhB or with mutations known to confer resistance to the SDHIs in SdhB. However, the frequency of C+ isolates was significantly higher in the SdhB wild-type isolates, which suggests that SDHI sprays may have played a role in selecting for the C- over the C+ genotype. Field C+ isolates exhibited reduced sensitivity to fluopyram and increased sensitivity to boscalid and penthiopyrad in vitro and on detached fruit. Homology modeling confirmed the positioning of the four mutations in the ubiquinone-binding pocket. The SdhCG85A is found in the proximal ubiquinone binding site and SdhCM158V is positioned in the iron sulfur protein interface next to the [3Fe-4S] cluster, whereas SdhCI93V is positioned next to the heme b with vital functions in the SDH enzyme. Beside the differential sensitivity to the SDHIs, these mutations caused a significant fitness cost in the C+ isolates including sporulation and increased sensitivity to reactive oxygen species. The presence of Botrytis populations differentially sensitive to the SDHIs suggests increased risks for resistance development but also opens up new perspective for future gray mold management using different SDHI fungicides.


Assuntos
Proteínas de Bactérias , Botrytis , Inibidores Enzimáticos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Botrytis/efeitos dos fármacos , Botrytis/genética , Farmacorresistência Fúngica , Inibidores Enzimáticos/farmacologia , Frutas/microbiologia , Fungicidas Industriais , Genótipo , Mutação , Doenças das Plantas/microbiologia
6.
Sci Total Environ ; 703: 135557, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767318

RESUMO

Combating drug-resistance is a daunting task, especially due to the shortage of available drug alternatives with multisite modes of action. In this study, the potential of copper nanoparticles (Cu-NPs) to suppress 15 Botrytis cinerea isolates, which are sensitive or resistant to fungicides, alone or in combination with conventional fungicides, was tested in vitro and in vivo. Sensitivity screening in vitro revealed two fungicide resistance phenotypes, resulting from target site mutations. DNA sequencing revealed three B. cinerea isolates highly resistant to benzimidazoles (BEN-R), thiophanare methyl (TM), and carbendazim, bearing the E198A resistance mutation in the ß-tubulin gene, and four isolates highly resistant to the QoI pyraclostrobin (PYR-R) with a G143A mutation in the cytb gene. Cu-NPs were equally effective against sensitive and resistant isolates. An additive/synergistic effect was observed between Cu-NPs and TM in the case of BEN-S isolates both in vitro and when applied in apple fruit. A positive correlation was observed between TM and TM + Cu-NPs treatments, suggesting that an increased TM availability in the target site could be related with the observed additive/synergistic action. No correlation between Cu(OH)2 and Cu-NPs sensitivity was found, indicating that different mechanisms govern the fungitoxic activity between nano and bulk counterparts. A synergistic profile was observed between Cu-NPs and fluazinam (FM) - an oxidative phosphorylation inhibitor - in all isolates regardless of resistance phenotype, suggesting that ATP metabolism could be involved in the mode of action of Cu-NPs. Furthermore, the observed cross sensitivity and antagonistic action between Cu-NPs and NaCl also provided evidence for copper ions contribution to the fungitoxic action of Cu-NPs. The results suggested that Cu-NPs in combination with conventional fungicides can provide the means for an environmentally safe, sustainable resistance management strategy by reducing fungicide use and combating resistance against B. cinerea.


Assuntos
Botrytis/efeitos dos fármacos , Cobre/química , Farmacorresistência Fúngica/efeitos dos fármacos , Nanopartículas Metálicas/química , Benzimidazóis , Carbamatos , Nanopartículas Metálicas/toxicidade , Fenótipo , Doenças das Plantas
7.
J Appl Microbiol ; 128(1): 232-241, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31544331

RESUMO

AIM: The aim of this paper was to determine whether the quality of formulated Pseudomonas fluorescens Pf153 can be influenced by changes in fermentation conditions. In this study, the influence of the fermentation temperature on the growth and its consequence on shelf life, viability and biocontrol efficacy of freeze-dried cells of P. fluorescens Pf153 was investigated. METHODS AND RESULTS: Cells of P. fluorescens Pf153 were grown at 20 and 28°C in flasks and fermenter and harvested in the mid-log and the beginning of the stationary phase. The survival during storage of freeze-dried cells was tested at 25°C. Cells fermented at 20°C survived in storage better than those grown at 28°C, irrespective of the harvesting time. Compared to the untreated control, in in vitro tests Pf153 was in all production temperature/duration combinations significantly effective against all tested Botrytis cinerea strains. But no differences between temperature/duration combinations were found. In bioassay on detached Vicia faba leaves, it was found that young cells, when fermented at 28°C had a significant positive influence on the biocontrol efficacy. CONCLUSIONS: These results demonstrate that fermentation parameters have an influence on the performance and quality of a formulated product. SIGNIFICANCE AND IMPACT OF THE STUDY: Only limited numbers of biocontrol products based on antagonistic pseudomonads are on the market. This can be attributed to the lack of suitable formulated products with high numbers of viable cells and a good shelf life. Currently, only limited information on the influence of the fermentation on subsequent downstreaming process is available. Within this study, we focused on the influence of the two important parameters fermentation temperature and harvest time on survival, shelf life and biocontrol efficacy of P. fluorescens Pf153.


Assuntos
Agentes de Controle Biológico , Preservação Biológica/métodos , Pseudomonas fluorescens/fisiologia , Agentes de Controle Biológico/farmacologia , Botrytis/efeitos dos fármacos , Fermentação , Liofilização , Viabilidade Microbiana , Temperatura Ambiente , Vicia faba/microbiologia
8.
Zhongguo Zhong Yao Za Zhi ; 44(18): 3954-3959, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31872730

RESUMO

Through investigation,it was found that the main disease of leaves was grey mold on Dendrobium officinale in Hubei province,which has a great impact on the yield and quality of D. officinale. The identification of morphological and molecular biological was used to prove that the pathogen was Botrytis cinerea. Through test the effect of 5 plant source fungicides and 4 antibiotic fungicides on mycelial growth of strain HS1,which proved 0. 3% eugenol had the best inhibitory effect,EC50 was 0. 29 mg·L-1,the second was1% osthol and EC50 was 1. 12 mg·L-1,the EC50 of 0. 5% matrine was 9. 16 mg·L-1,the EC50 of the other six fungicides was higher than 10 mg·L-1. The field control effect test proved that 0. 3% eugenol had the best control effect,reaching 89. 44%,secondly for 1%osthole,which was 77. 17%,0. 5% matrine was in the third place with 62. 37% of effective rate. However,the control effect of the other fungicides was less than 60%. The three plant-derived fungicides were safe for the produce of D. officinale and showed no phytotoxicity. The effect of these fungicides on the growth of D. candidum was tested,and proved that all the fungicides were safe and harmless to D. candidum. This study provides a research basis for the safe and effective prevention and control gray mold of D. officinale.


Assuntos
Botrytis/patogenicidade , Dendrobium/microbiologia , Fungicidas Industriais , Doenças das Plantas/microbiologia , Alcaloides , Botrytis/efeitos dos fármacos , Cumarínicos , Eugenol , Doenças das Plantas/prevenção & controle , Folhas de Planta/microbiologia , Quinolizinas
9.
J Agric Food Chem ; 67(49): 13706-13717, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31693347

RESUMO

Tomato storage conditions are difficult largely due to Botrytis cinerea infection which causes gray mold disease. However, the effects of the volatile organic compounds (VOCs) emitted by postharvest tomatoes on this fungus remain unclear. We analyzed the effects of tomato-emitted VOCs on B. cinerea pathogenicity, germination, and hyphal growth with bioassay, predicted the causative active compounds by principle component analysis, identified G-protein-coupled receptors (GPCRs) which captured chemical signals in the B. cinerea genome by stimulating molecular docking, tested the binding affinities of these receptors for the active compounds by fluorescence binding competition assay, and identified an associated signaling pathway by RNA interfere. The VOCs emitted by postharvest tomatoes inhibited B. cinerea; ethylene and benzaldehyde were the active compounds causing this effect. One of the identified GPCRs in B. cinerea, BcGPR3, bound tightly to both active compounds. Two genes associated with the cAMP signaling pathway (BcRcn1 and BcCnA) were downregulated in wild-type B. cinerea exposed to the active compounds, as well as in the ΔBcgpr3 B. cinerea mutant. Exposure to postharvest tomato VOCs reduces B. cinerea pathogenicity due to ethylene and benzaldehyde volatiles. The BcGPR3 protein is inactivated by the active compounds, and thus fails to transmit signals to the cAMP pathway, thereby inhibiting B. cinerea.


Assuntos
Benzaldeídos/farmacologia , Botrytis/efeitos dos fármacos , AMP Cíclico/metabolismo , Etilenos/farmacologia , Proteínas Fúngicas/metabolismo , Lycopersicon esculentum/química , Receptores Acoplados a Proteínas-G/metabolismo , Benzaldeídos/metabolismo , Botrytis/genética , Botrytis/metabolismo , Etilenos/metabolismo , Proteínas Fúngicas/genética , Lycopersicon esculentum/metabolismo , Simulação de Acoplamento Molecular , Doenças das Plantas/microbiologia , Receptores Acoplados a Proteínas-G/genética , Transdução de Sinais/efeitos dos fármacos , Compostos Orgânicos Voláteis/metabolismo , Compostos Orgânicos Voláteis/farmacologia
10.
Carbohydr Polym ; 226: 115256, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31582056

RESUMO

In order to improve the antioxidant and antifungal activity of chitosan, eight chitosan derivatives containing Schiff bases and quaternary ammonium salts were synthesized via an intermediate 6-O-chloroacetyl-2-N,N,N-trimethyl quaternary ammonium salt chitosan. Detailed structural characterization was carried out using FTIR and 1H NMR spectroscopy, and elemental analysis. The antifungal activity against F. oxysporum f. sp. cucumerium, B. cinerea, and F. oxysporum f. sp. niveum was evaluated using a mycelium growth rate test. The results indicated that the chitosan derivatives exhibited enhanced antifungal activity when compared to chitosan, especially at 1.0 mg/mL. 6-[4-(2,3-dihydroxyl-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (2.3HBPATC), 6-[4-(2,3,4-trihydroxyl-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (2.3.4HBPATC), 6-[4-(2-fluorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (FBPATC), 6-[4-(2-chlorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (CBPATC), 6-[4-(2-bromine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (BBPATC), and 6-[4-(2-hydroxyl-4-chlorine-benzimide) pyridine] acetyl-2-N,N,N-trimethyl-chitosan chloride (HCBPATC) showed inhibitory indices >90.0% at 1.0 mg/mL against F. oxysporum f. sp. cucumerium and B. cinerea. Furthermore, the chitosan derivatives showed stronger antioxidant activity than chitosan, especially 2.3HBPATC and 2.3.4HBPATC with inhibitory indices of 100.0% at 1.6 mg/mL against DPPH and superoxide radicals. Based on these data, it is reasonable to suggest that the introduction of phenolic hydroxyl and halogen groups enhances the antifungal and antioxidant activity of chitosan.


Assuntos
Antifúngicos , Antioxidantes , Botrytis/efeitos dos fármacos , Quitosana/análogos & derivados , Fusarium/efeitos dos fármacos , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Antioxidantes/síntese química , Antioxidantes/química , Antioxidantes/farmacologia , Compostos de Amônio Quaternário/química , Bases de Schiff/química , Relação Estrutura-Atividade
11.
J Agric Food Chem ; 67(43): 11901-11910, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31584275

RESUMO

Encouraged by the successful flexible modifications of the succinate dehydrogenase inhibitors, antifungal activity guided by the divergent synthesis of nicotinamides of the prevalidated pharmacophore 2-(2-oxazolinyl)aniline was conducted. The work highlighted the first utilization of the late-stage C-H functionalization assisted by the innate pharmacophore for the discovery of promising agrochemicals. New synthetic methodology and antifungal exploration of alkoxylated nicotinamides were accomplished. Fifty-five functionalized nicotinamides of 7 types were rationally designed and efficiently prepared through C-H functionalization, which facilitated the acquirement of four N-para aryloxylated nicotinamides (E3, E13, E19, and E22) as potential antifungal candidates against Botrytis cinerea, with the EC50 values lower than 5 mg/L. In vivo/vitro biotest, molecular docking, and structural analysis reconfirmed the novelty and practical potential of the antifungal candidates E3 and E19. This operationally simple platform will provide various "polar parts" and offer intriguing opportunities for the optimization of the carboxamide fungicides and structure-related pharmaceuticals.


Assuntos
Fungicidas Industriais/química , Niacinamida/química , Botrytis/química , Botrytis/efeitos dos fármacos , Botrytis/enzimologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Proteínas Fúngicas/antagonistas & inibidores , Proteínas Fúngicas/química , Fungicidas Industriais/farmacologia , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Niacinamida/farmacologia , Doenças das Plantas/microbiologia , Relação Estrutura-Atividade , Succinato Desidrogenase/antagonistas & inibidores , Succinato Desidrogenase/química
12.
J Agric Food Chem ; 67(45): 12357-12365, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31596575

RESUMO

A series of isothiazole, 1,2,3-thiadiazole, and thiazole-based cinnamamide morpholine derivatives were rationally designed, synthesized, characterized, and evaluated for their fungicidal activities. Bioassay indicated that a combination of 3,4-dichloroisothiazole active substructures with cinnamamide morpholine lead to significant improvement of in vivo antifungal activities of the target compounds; among them, compound 5a exhibited good fungicidal activity against Pseudoperonspera cubensis in vivo with an inhibition rate of 100% at 100 µg/mL. A field experiment indicated that the difference of efficacy between 5a (75.9%) and dimethomorph (77.1%) at 37.5 g ai/667 m2 was not significant; and 5a also exhibited good activity against Botrytis cinerea by triggering accumulation of PAL and NPR1 defense-related gene expression and the defense associated enzyme phenylalanine ammonia-lyase (PAL) expression on cucumber, rather than direct inhibition. These findings strongly supported that 3,4-dichloroisothiazole containing cinnamamide morpholine 5a not only showed good fungicidal activity against P. cubensis but also exhibited plant innate immunity stimulation activity as a promising fungicide candidate with both fungicidal activity and systemic acquired resistance.


Assuntos
Cinamatos/química , Fungicidas Industriais/síntese química , Tiadiazóis/química , Tiazóis/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Cinamatos/farmacologia , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/microbiologia , Descoberta de Drogas , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Estrutura Molecular , Doenças das Plantas/microbiologia , Relação Estrutura-Atividade , Tiadiazóis/farmacologia
13.
Molecules ; 24(14)2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31319619

RESUMO

In order to explore more efficient sulfonamides against Botrytis cinereal, 36 novel cyclohexylsulfonamides were synthesized by N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDCI) and 1-hydroxybenzotriazole (HOBt) condensation reaction using chesulfamide as a lead compound, introducing thiazole and pyrazole active groups. Their structures were characterized by 1H-NMR, 13C-NMR, mass spectrum (MS), and elemental analysis. Compound III -31 was further confirmed by X-ray single crystal diffraction. The in vitro and in vivo fungicidal activities against B. cinerea were evaluated by three bioassay methods. The results of mycelial growth demonstrated that median effective concentration (EC50) values of nine compounds were close to boscalid (EC50 = 1.72 µg/mL) and procymidone (EC50 = 1.79 µg/mL) against B. cinerea (KZ-9). In the spore germination experiment, it was found that compounds III-19 and III-31 inhibited germination 93.89 and 98.00%, respectively; at 10 µg/mL, they approached boscalid (95.97%). In the tomato pot experiment, the control effects of two compounds (III-21 and III-27) were 89.80 and 87.90%, respectively, at 200 µg/mL which were significantly higher than boscalid (81.99%). The structure-activity relationship (SAR) was also discussed, which provided a valuable idea for developing new fungicides.


Assuntos
Botrytis/efeitos dos fármacos , Fungicidas Industriais/química , Sulfonamidas/química , Botrytis/patogenicidade , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/farmacologia , Tiazóis/síntese química , Tiazóis/química
14.
J Sci Food Agric ; 99(14): 6552-6561, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31321781

RESUMO

BACKGROUND: Essential oils (EOs) are volatile natural compounds produced by plant secondary metabolism, and some of them exhibit antimicrobial activity. The objective of the present study was to determine the chemical composition the EOs of Eucalyptus staigeriana and Eucalyptus globulus, and their effect in vitro and in vivo against Botrytis cinerea and Colletotrichum acutatum, the most important fungal rot diseases of grapes. Moreover, grapes collected from field experiments were used to evaluate the impact of the alternative control on the alcoholic fermentation and wine composition. RESULTS: The major compound of E. staigeriana EO were citral 30.91% (19.74% geranial, 11.17% neral), 1.8-cineole (24.59%) and limonene (19.47%), while 1.8-cineole represented 68.26% of E. globulus EO. The two EOs showed in vitro antifungal activity against both pathogens. Eucalyptus staigeriana EO exhibited the highest activity inhibiting mycelial growth (MG) and conidial germination at 0.5 µL mL-1 . Moreover, this EO was able to reduce the incidence and severity of grey rot caused by B. cinerea and the severity of ripe rot caused by C. acutatum The alternative control did not significantly influence alcoholic fermentation, the physicochemical characteristics, and the volatile composition of wines. CONCLUSION: These results are promising and indicate that E. staigeriana EO might be further investigated as a natural alternative for the control of fungal rots on wine grapes. © 2019 Society of Chemical Industry.


Assuntos
Antifúngicos/farmacologia , Eucalyptus/química , Óleos Voláteis/farmacologia , Doenças das Plantas/prevenção & controle , Extratos Vegetais/farmacologia , Vitis/microbiologia , Antifúngicos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Óleos Voláteis/química , Doenças das Plantas/microbiologia , Extratos Vegetais/química
15.
Plant Dis ; 103(9): 2385-2391, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31313639

RESUMO

Stimulatory effects of low doses of fungicides on the virulence of phytopathogens have profound implications for applications of fungicides. The present study demonstrated that carbendazim sprayed at 0.001 to 0.03 µg/ml had stimulatory effects on the virulence of mycelia of Botrytis cinerea, and the maximum percent stimulations were 15.5 and 21.4% for isolates HB459 and HB536, respectively. Potato dextrose agar (PDA) amended with carbendazim at 0.01, 0.02, and 0.05 µg/ml inhibited mycelial growth of isolate HB536 by 0.8, 10.0, and 30.6%, respectively. However, after the inhibited mycelia were inoculated on cucumber leaves, virulence increased by 10.1, 12.9, and 10.8%, respectively. With respect to sclerotial production, carbendazim at 0.005 and 0.02 µg/ml in PDA significantly (P < 0.05) increased, while at 0.1 µg/ml significantly (P < 0.05) reduced the sclerotial number and weight of both isolates compared with nontreated controls. Conidia germination percentages slightly yet statistically significantly (P < 0.05) increased after being inoculated on PDA amended with carbendazim at 0.001 and 0.005 µg/ml. Carbendazim at 0.001∼0.02 µg/ml, either sprayed on cucumber leaves or cosuspended with conidia, exerted significantly (P < 0.05) stimulatory effects on the virulence of B. cinerea conidia. Mechanism studies showed that sublethal doses of carbendazim did not increase the expression levels of pathogenicity-related pectin methylesterase gene Bcpme1, endopolygalacturonase gene Bcpg2, cutinase gene CutA, xylanase gene Xyn11A, or NADPH oxidase gene BcnoxA.


Assuntos
Benzimidazóis , Botrytis , Carbamatos , Doenças das Plantas , Virulência , Benzimidazóis/farmacologia , Botrytis/efeitos dos fármacos , Carbamatos/farmacologia , Virulência/efeitos dos fármacos
16.
J Agric Food Chem ; 67(33): 9265-9276, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31361479

RESUMO

Fungal infections significantly alter the emissions of volatile organic compounds (VOCs) by plants, but the mechanisms for VOCs affecting fungal infections of plants remain largely unknown. Here, we found that infection by Botrytis cinerea upregulated linalool production by strawberries and fumigation with linalool was able to inhibit the infection of fruits by the fungus. Linalool treatment downregulated the expression of rate-limiting enzymes in the ergosterol biosynthesis pathway, and this reduced the ergosterol content in the fungi cell membrane and impaired membrane integrity. Linalool treatment also caused damage to mitochondrial membranes by collapsing mitochondrial membrane potential and also downregulated genes involved in adenosine triphosphate (ATP) production, resulting in a significant decrease in the ATP content. Linalool treatment increased the levels of reactive oxygen species (ROS), in response to which the treated fungal cells produced more of the ROS scavenger pyruvate. RNA-Seq and proteomic analysis data showed that linalool treatment slowed the rates of transcription and translation.


Assuntos
Botrytis/efeitos dos fármacos , Fragaria/metabolismo , Frutas/microbiologia , Monoterpenos/metabolismo , Doenças das Plantas/microbiologia , Compostos Orgânicos Voláteis/metabolismo , Trifosfato de Adenosina/metabolismo , Botrytis/crescimento & desenvolvimento , Fragaria/química , Fragaria/microbiologia , Frutas/química , Frutas/metabolismo , Interações Hospedeiro-Patógeno , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Monoterpenos/farmacologia , Doenças das Plantas/prevenção & controle , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteômica , Espécies Reativas de Oxigênio/metabolismo , Compostos Orgânicos Voláteis/farmacologia
17.
J Agric Food Chem ; 67(27): 7626-7639, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31241941

RESUMO

A novel series of simple 1,3,4-oxadiazoles that bear flexible heterocyclic patterns was prepared, and their biological activities in plant pathogenic bacteria, fungi, oomycetes, and Meloidogyne incognita in vitro and in vivo were screened to explore low-cost and versatile antimicrobial agents. Screening results showed that compounds, such as A0, B0, and C4, were bioactive against Xanthomonas oryzae pv oryzae in vitro and in vivo, and such bioactivities were superior to those of commercial agents bismerthiazol and thiodiazole copper. Their antibacterial mechanisms were further investigated by quantitative proteomics and concentration-dependent scanning electron microscopy images. Antifungal results indicated that compound A0 displayed a selective and better antifungal effect on Botrytis cinerea with inhibition rate of 96.8% at 50 µg/mL. Nematocidal bioassays suggested that compound D1 had good in vitro nematocidal activity toward M. incognita at 24, 48, and 72 h, with the corresponding insecticidal efficiency of 48.7%, 64.1%, and 87.2% at 40 µg/mL. In vivo study further confirmed that compounds D1 and F2 showed nematocidal actions at 80 µg/mL with a disease index of 1.5. Given these advantages, this kind of molecular frameworks could be a suitable platform for exploring highly efficient agrochemicals.


Assuntos
Anti-Infecciosos , Compostos Heterocíclicos/química , Oxidiazóis/química , Oxidiazóis/farmacologia , Plantas/microbiologia , Proteômica , Animais , Antibacterianos , Antinematódeos , Botrytis/efeitos dos fármacos , Fungicidas Industriais , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Estrutura Molecular , Oxidiazóis/síntese química , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Relação Estrutura-Atividade , Tylenchoidea/efeitos dos fármacos , Xanthomonas/efeitos dos fármacos
18.
Plant Dis ; 103(8): 1884-1888, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161931

RESUMO

It is a common practice to add salicylhydroxamic acid (SHAM) into artificial medium in the in vitro sensitivity assay of fungal phytopathogens to the quinone outside inhibitor (QoI) fungicides. The rationale for adding SHAM is to inhibit fungal alternative oxidase, which is presumed to be inhibited by secondary metabolites of plants. Therefore, the ideal characteristics of SHAM should be almost nontoxic to phytopathogens and have no significant effect on control efficacy of fungicides. However, this study showed that the average effective concentration for 50% inhibition (EC50) of mycelial growth values of SHAM were 97.5 and 401.4 µg/ml for Sclerotinia sclerotiorum and Botrytis cinerea, respectively. EC50 values of the three QoI fungicides azoxystrobin, kresoxim-methyl, and trifloxystrobin in the presence of SHAM at 20 and 80 µg/ml for S. sclerotiorum and B. cinerea, respectively, declined by 52.7 to 78.1% compared with those without SHAM. For the dicarboximide fungicide dimethachlone, the average EC50 values in the presence of SHAM declined by 18.2% (P = 0.008) for S. sclerotiorum and 35.9% (P = 0.012) for B. cinerea. Pot experiments showed that SHAM increased control efficacy of the three QoI fungicides against the two pathogens by 43 to 83%. For dimethachlone, SHAM increased control efficacy by 134% for S. sclerotiorum and 86% for B. cinerea. Biochemical studies showed that SHAM significantly inhibited peroxidase activity (P = 0.024) of B. cinerea and esterase activity (P = 0.015) of S. sclerotiorum. The strong inhibitions of SHAM per se on mycelial growth of B. cinerea and S. sclerotiorum and significant influences on the sensitivity of the two pathogens to both the QoI fungicides and dimethachlone as well as inhibitions on peroxidase and esterase indicate that SHAM should not be added in the in vitro assay of sensitivity to the QoI fungicides.


Assuntos
Ascomicetos , Botrytis , Farmacorresistência Fúngica , Fungicidas Industriais , Salicilamidas , Ascomicetos/efeitos dos fármacos , Botrytis/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Salicilamidas/farmacologia
19.
Food Chem ; 293: 263-270, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151610

RESUMO

Gray mold caused by Botrytis cinerea is the most important disease in postharvest tomato fruit. Inducing resistance to fungal pathogens in the harvested fruit and vegetable is a promising approach to control postharvest losses. In the present study, the effect of l-glutamate on induction of resistance to B. cinerea and the underlying mechanisms were investigated. The results indicated that l-glutamate at 100 ppm was effective in reducing the gray mold of tomatoes after inoculation of the pathogen. Gene expressions of nine glutamate receptors, four pathogenesis-related proteins and the content of amino acids were affected by l-glutamate treatment. Furthermore, the metabolites of l-glutamate, including GABA, Met, Lys and Arg, could also induce significant resistance against B. cinerea in tomato fruit. Our findings suggested that l-glutamate treatment may represent a promising method for managing postharvest decay of tomato fruit.


Assuntos
Aminoácidos/metabolismo , Botrytis/efeitos dos fármacos , Ácido Glutâmico/farmacologia , Lycopersicon esculentum/imunologia , Micoses/prevenção & controle , Doenças das Plantas/prevenção & controle , Receptores de Glutamato/metabolismo , Resistência à Doença , Frutas/química , Lycopersicon esculentum/genética , Lycopersicon esculentum/microbiologia , Micoses/microbiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Regulação para Cima/efeitos dos fármacos
20.
Plant Dis ; 103(8): 1991-1997, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31169087

RESUMO

Gray mold caused by Botrytis cinerea can be a severe disease of tomato infecting leaves and fruits of tomato plants. Chemical control is currently the most effective and reliable method; however, application of fungicides has many drawbacks. The combination of biological control agents with newly developed fungicides may be a practicable method to control B. cinerea. Fluopimomide is a newly developed fungicide with a novel mode of action. Bacillus methylotrophicus TA-1, isolated from rhizosphere soil of tomato, is a bacterial strain with a broad spectrum of antimicrobial activities. Little information is currently available about the effect of fluopimomide and its integrated effect on B. cinerea. Therefore, laboratory, pot, and field experiments were carried out to determine the effects of fluopimomide alone and in combination with B. methylotrophicus TA-1 against gray mold on tomato. The in vitro growth of B. methylotrophicus TA-1 was unaffected by 100 mg liter-1 fluopimomide. Inhibition of B. cinerea mycelial growth was significantly increased under combined treatment of fluopimomide and B. methylotrophicus TA-1. In greenhouse experiments, efficacy against gray mold was significantly greater by an integration of fluopimomide and B. methylotrophicus TA-1 than by either alone; control efficacy of fluopimomide at 50 and 100 g ha-1 in combination with B. methylotrophicus TA-1 at 108 colony-forming units (cfu) ml-1 reached 70.16 and 69.32%, respectively, compared with the untreated control. In both field trials during 2017 and 2018, control efficacy was significantly higher for the combination of fluopimomide at 50 and 100 g ha-1 in combination with B. methylotrophicus TA-1 than for either treatment alone. The results from this study indicated that integration of the new fungicide fluopimomide with the biocontrol agent B. methylotrophicus TA-1 synergistically increased control efficacy of the fungicide against gray mold of tomato.


Assuntos
Bacillus , Botrytis , Fungicidas Industriais , Lycopersicon esculentum , Doenças das Plantas , Bacillus/fisiologia , Botrytis/efeitos dos fármacos , Botrytis/fisiologia , Fungicidas Industriais/farmacologia , Lycopersicon esculentum/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
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