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1.
J Agric Food Chem ; 67(38): 10646-10652, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31479255

RESUMO

A new monosesquiterpene diacetylgliocladic acid (1), a new dimeric sesquiterpene divirensol H (9), and two exceptionally novel trimeric sesquiterpene trivirensols A and B (11 and 12), together with another eight known congeners, were purified from an endophytic fungus Trichoderma virens FY06, derived from Litchi chinensis Sonn. whose fruit is a delicious and popular food. All of them were identified by comprehensive spectroscopic analysis, combined with biosynthetic considerations. Trivirensols A and B are unprecedented trimers of which three subunits are connected by two ester bonds of the sesquiterpene class. Relative to the positive control triadimefon, all the tested metabolites showed strong inhibitory activities against at least one phytopathogenic fungus among Penicillium italicum, Fusarium oxysporum, Fusarium graminearum, Colletotrichum musae, and Colletotrictum gloeosporioides. Notably, as metabolites of the endophytic fungus from L. chinensis, they all presented strong antifungal activities against C. gloeosporioides which causes anthracnose in L. chinensis.


Assuntos
Fungicidas Industriais/farmacologia , Litchi/microbiologia , Sesquiterpenos/farmacologia , Trichoderma/química , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Endófitos/química , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/metabolismo , Frutas/microbiologia , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Doenças das Plantas/microbiologia , Sesquiterpenos/química , Sesquiterpenos/metabolismo , Trichoderma/genética , Trichoderma/isolamento & purificação
2.
Pestic Biochem Physiol ; 158: 18-24, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378355

RESUMO

Outbreaks of bitter rot were observed in three commercial apple orchards in Illinois despite best management efforts during the 2018 production season. Three isolates from symptomatic fruit from these orchards and two isolates from an orchard in South Carolina were identified to the species level using morphological tools and calmodulin, glyceraldehyde-3-phosphate dehydrogenase, and beta-tubulin gene sequences. The isolates from Illinois were identified as Colletotrichum siamense of the Colletotrichum gloeosporioides species complex and the ones from South Carolina as Colletotrichum fioriniae and Colletotrichum fructicola of the Colletotrichum acutatum and the C. gloeosporioides species complex, respectively. Two of the three C. siamense isolates from Illinois were resistant to azoxystrobin and thiophanate-methyl as determined in mycelial growth tests in vitro. EC50 values were >100 µg/ml for both fungicides. One isolate was only resistant to azoxystrobin. None of the isolates from South Carolina was resistant to either of the two compounds. All five isolates were sensitive to fludioxonil (EC50 values <0.1 µg/ml), propiconazole (EC50 values ranged from 0.15 to 0.36 µg/ml), and benzovindiflupyr (EC50 values ranged from <0.1 to 0.33 µg/ml). Resistance in C. siamense to azoxystrobin and thiophanate-methyl was confirmed in detached fruit studies using apples treated with label rates of registered product. Resistance to thiophanate-methyl in C. siamense was based on E198A mutation in b-tubulin gene, whereas resistance to azoxystrobin was based on G143A in cytochrome b (CYTB). One isolate resistant to azoxystrobin possessed no amino acid variation in CYTB. This study shows that quinone outside inhibitor fungicide resistance in Colletotrichum from apple has emerged and is being selected for in Illinois apple orchards by current spray strategies. Resistance monitoring may alert growers to potential threats, but the employment of molecular tools based on current knowledge of resistance mechanisms will provide incomplete results.


Assuntos
Colletotrichum/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Malus/microbiologia , Benzimidazóis/farmacologia , Colletotrichum/genética , Citocromos b/genética , Citocromos b/metabolismo , Dioxóis/farmacologia , Farmacorresistência Fúngica/genética , Frutas/microbiologia , Malus/genética , Norbornanos/farmacologia , Pirazóis/farmacologia , Pirimidinas/farmacologia , Pirróis/farmacologia , Estrobilurinas/farmacologia , Tiofanato/farmacologia , Triazóis/farmacologia
3.
Plant Dis ; 103(10): 2505-2511, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31408403

RESUMO

Botrytis fruit rot (BFR) is a major disease that affects strawberry production in Florida and worldwide. BFR management relies on frequent fungicide applications. A meta-analysis was conducted on the outcomes from nine field trials to evaluate the efficacy and profitability of conventional and biological fungicides compared with a nontreated control (NTC). All trials were conducted in Florida between the 2005/06 and 2016/17 growing seasons. Fungicide treatments were applied weekly, and plots were harvested twice a week for yield and BFR incidence quantification. Treatments were grouped into four categories: NTC, multisite only (Thiram), Standard (captan alternated with fludioxonil + cyprodinil), and Bacillus. Following primary analyses, a random effects network meta-analytical model was fitted to estimate the mean yield and BFR incidence responses for each treatment group and to compare means between pairs of groups. The Thiram and the Standard treatment groups increased yield by 378.8 and 502.2 kg/ha/week, respectively, compared with the NTC. The yield difference between Bacillus and NTC was not statistically significant. Besides increasing yield, Thiram and Standard also reduced BFR incidence by approximately 10% compared with the NTC. The mean yield responses and among-study variability from the meta-analysis were used to estimate the probability of a given yield response in a new future trial. The Standard and Thiram treatment groups showed higher estimated probabilities of increasing yield and resulting in a profitable return on application investments than the Bacillus group of treatments. The results from this study provide growers with information that will aid their decision-making process regarding BFR management.


Assuntos
Bacillus , Botrytis , Fragaria , Fungicidas Industriais , Controle Biológico de Vetores , Bacillus/fisiologia , Botrytis/fisiologia , Florida , Fragaria/microbiologia , Frutas/microbiologia , Fungicidas Industriais/economia , Fungicidas Industriais/normas , Controle Biológico de Vetores/economia , Controle Biológico de Vetores/normas
4.
Plant Dis ; 103(9): 2374-2384, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31306090

RESUMO

The Botryosphaeriaceae family is considered a fungal family that includes pathogens causing latent infection of woody plants, and a number of species were identified as causal pathogens of canker and shoot blight diseases. To better understand the process of latent infection of major canker-causing pathogens in woody tissues in different tree crops important in California, shoot and bud samples were randomly collected from four tree crops: almond, dried plum, pistachio, and walnut. The previously developed DNA primers and quantitative real-time PCR (qPCR) assay systems were applied to detect six canker-causing pathogen groups, including Botryosphaeria dothidea, and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis. The concepts of molecular severity (MS) and latent infection index (LII) were introduced and applied to quantify the latent infection levels for these samples. Variation in incidence of latent infection among pathogen groups was observed, whereas the incidences were relatively low among species of Phomopsis and Diplodia. High incidences of Cytospora spp. were observed in two dried plum (prune) orchards. Most orchards showed high incidences of B. dothidea and Lasiodiplodia spp. and moderate incidences of Neofusicoccum spp. Variations in MS were observed among samples of the studied orchards, ranging from 4 to 8. The overall results of LII demonstrated that species of Diplodia and Phomopsis were less important in population development of canker-causing pathogens at the latent phase. Lasiodiplodia spp. were the most aggressive and had been well developed in populations among the studied tree crops. Cytospora spp. became predominant in two of the three dried plum orchards, whereas B. dothidea and Neofusicoccum spp. showed trends of increase in incidence across various tree crops. This study also demonstrated the usefulness of this sensitive qPCR approach in providing evidence of the latent phase of major canker-causing pathogens of stone fruit and nut crops at an early stage of latent infection in woody plant tissues.


Assuntos
Ascomicetos , Frutas , Nozes , Árvores , Ascomicetos/classificação , Ascomicetos/fisiologia , California , DNA Fúngico , Frutas/microbiologia , Nozes/microbiologia , Filogenia , Doenças das Plantas , Árvores/microbiologia
5.
Plant Dis ; 103(9): 2305-2314, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31306092

RESUMO

Monilinia laxa and M. fructicola are two causal agents of brown rot, one of the most important diseases in stone fruit. Two species cause blight on blossoms and twigs and brown rot on fruit in pre- and postharvest. Both species are distributed worldwide in North and South America, Australia, and Japan. In Europe, M. laxa is endemic, while M. fructicola was introduced in 2001 and it is now widespread in several countries. Currently, both species coexist in European stone fruit orchards. Monilinia spp. overwinter in cankers and mummified fruit. Mummy monitoring during winter permits growers to understand which species of Monilinia will be prevalent in an orchard during the following season, permitting planning of an appropriate crop protection. Traditionally, the identification has been carried out using morphological features and even with polymerase chain reaction (PCR)-based assays that requires time and well-equipped laboratories. In this study, two isothermal-based methods were designed to identify these pathogens in a faster way than using traditional methods. The loop-mediated amplification (LAMP) assays were validated on some isolates of Monilinia spp. coming from the mummy monitoring according to the international European and Mediterranean Plant Protection Organization standard (PM7/98), taking into account specificity, sensitivity, repeatability, and reproducibility. The sensitivity of both assays was checked by monitoring (at different time points) two nectarine varieties artificially inoculated and stored at two different temperatures. The reliability of both LAMP assays against the quantification of the inoculum was compared with previously published quantitative PCR assays. Both LAMP methods were able to detect a low number of cells. These LAMP methods could be a useful tool for monitoring brown rot causal agents in the field and during postharvest.


Assuntos
Técnicas de Amplificação de Ácido Nucleico , Doenças das Plantas , Prunus persica , Frutas/microbiologia , Doenças das Plantas/microbiologia , Prunus persica/microbiologia , Reprodutibilidade dos Testes
6.
Plant Dis ; 103(9): 2433-2442, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31306093

RESUMO

Postbloom fruit drop (PFD) of citrus, caused by Colletotrichum acutatum sensu lato and C. gloeosporioides sensu lato, is an important disease in the humid tropics of the American continent. PFD mainly affects flowers, on which typical symptoms are characterized by orange-brown lesions with presence of acervuli. The disease has a sporadic occurrence, but preventative fungicide sprays are applied every season. The objective of this study was to evaluate the effectiveness of a fungicide spray strategy for PFD based on a predictive model of C. acutatum conidium germination linked to weather conditions. Fungicide sprays were performed when the model predicted pre-established thresholds of 10, 15, 20, and 25% of germinated spores (T10, T15, T20, and T25, respectively). Five experiments were conducted in two different seasons in the state of São Paulo, Brazil. PFD control efficacy of the threshold-based treatments was compared with a nontreated control and to a calendar-based spray system. Additionally, an economic analysis was performed to assess the gross income revenues of the fungicide spraying strategies. Disease control in plots treated at T10, T15, and T20 was as effective as the calendar-based strategy. The number of fungicide applications was reduced by 33 to 71% when sprays were applied at T15 and T20, and gross income increased or was comparable to that of the other treatments. Therefore, using a conidium germination model with a threshold of 15 or 20% is recommended as a spraying strategy for PFD management in Brazil.


Assuntos
Citrus , Fungicidas Industriais , Doenças das Plantas , Brasil , Citrus/microbiologia , Frutas/microbiologia , Fungicidas Industriais/economia , Doenças das Plantas/economia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
7.
J Agric Food Chem ; 67(33): 9232-9240, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31347839

RESUMO

The hydrophobic wax layer of pepper fruit (Capsicum frutescens L.) increases the importance of selecting adjuvants that improve the wetting property of droplets on the target organism and increase the effective utilization of fungicides. In this study, the effect of adjuvants including nonionic, cationic, organosilicone, and oils on the wettability of fungicides was determined. The critical micelle concentrations for S903 (organosilicone), 1227 (cationic), AEO-5 (nonionic), GY-Tmax (oil), and XP-2 (oil) were 25, 1000, 100, 200, and 500 mg/L, respectively. Interface behaviors and in vivo tests suggested that adjuvants at appropriate concentrations (S903, 2.5 mg/L; 1227, 100 mg/L; AEO-5, 1 mg/L; GY-Tmax, 50 mg/L; and XP-2, 5 mg/L) resulted in optimum efficiency. Adjuvants significantly increased the inhibitory activity of pyraclostrobin against the mycelial growth, spore germination, and germ tube elongation of Colletotrichum scovillei by 41.3-58.8%, 28.2-44.6%, and 27.8-39.8%, respectively. Pyraclostrobin amended with S903 and XP-2 showed higher efficacy against anthracnose than the fungicide alone on pepper fruit. The increased efficacy may have resulted from the changed crystal morphology (ellipses of similar sizes), improved wettability, and rainfastness. A structural equation model indicated that surface tension and retention play the most important roles in the application properties of fungicide. In field experiments, the efficacy of pyraclostrobin with adjuvants showed no significant difference with pyraclostrobin alone, which indicated that, except for adjuvants, other spraying technologies are important for improving the field performance of fungicides. These results provide a foundation for the synthesis of highly efficient fungicides based on crystal structure and for the sustainable management of pepper anthracnose.


Assuntos
Portadores de Fármacos/química , Fungicidas Industriais/química , Estrobilurinas/química , Capsicum/microbiologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Cristalização , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Micelas , Compostos de Organossilício/química , Doenças das Plantas/microbiologia , Estrobilurinas/farmacologia , Molhabilidade
8.
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
9.
Plant Mol Biol ; 101(1-2): 149-162, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267255

RESUMO

KEY MESSAGE: Here we describe that the regulation of MdWRKY31 on MdHIR4 in transcription and translation levels associated with disease in apple. The phytohormone salicylic acid (SA) is a main factor in apple (Malus domestica) production due to its function in disease resistance. WRKY transcription factors play a vital role in response to stress. An RNA-seq analysis was conducted with 'Royal Gala' seedlings treated with SA to identify the WRKY regulatory mechanism of disease resistance in apple. The analysis indicated that MdWRKY31 was induced. A quantitative real-time polymerase chain reaction (qPCR) analysis demonstrated that the expression of MdWRKY31 was induced by SA and flg22. Ectopic expression of MdWRKY31 in Arabidopsis and Nicotiana benthamiana increased the resistance to flg22 and Pseudomonas syringae tomato (Pst DC3000). A yeast two-hybrid screen was conducted to further analyze the function of MdWRKY31. As a result, hypersensitive-induced reaction (HIR) protein MdHIR4 interacted with MdWRKY31. Biomolecular fluorescence complementation, yeast two-hybrid, and pull-down assays demonstrated the interaction. In our previous study, MdHIR4 conferred decreased resistance to Botryosphaeria dothidea (B. dothidea). A viral vector-based transformation assay indicated that MdWRKY31 evaluated the transcription of SA-related genes, including MdPR1, MdPR5, and MdNPR1 in an MdHIR4-dependent way. A GUS analysis demonstrated that the w-box, particularly w-box2, of the MdHIR4 promoter played a major role in the responses to SA and B. dothidea. Electrophoretic mobility shift assays, yeast one-hybrid assay, and chromatin immunoprecipitation-qPCR demonstrated that MdWRKY31 directly bound to the w-box2 motif in the MdHIR4 promoter. GUS staining activity and a protein intensity analysis further showed that MdWRKY31 repressed MdHIR4 expression. Taken together, our findings reveal that MdWRKY31 regulated plant resistance to B. dothidea through the SA signaling pathway by interacting with MdHIR4.


Assuntos
Resistência à Doença , Malus/genética , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Ácido Salicílico/farmacologia , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Ascomicetos/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Frutas/genética , Frutas/imunologia , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes Reporter , Malus/imunologia , Malus/microbiologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Regiões Promotoras Genéticas/genética , Pseudomonas syringae/fisiologia , Plântula/genética , Plântula/imunologia , Plântula/microbiologia , Transdução de Sinais , Tabaco/genética , Tabaco/imunologia , Tabaco/microbiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
10.
BMC Plant Biol ; 19(1): 289, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262259

RESUMO

BACKGROUND: Banana anthracnose, caused by Colletotrichum musae, is one of the most severe postharvest diseases in banana. Melatonin is widely known for its role in enhancing plant stress tolerance. However, little is known about the control of melatonin on anthracnose in postharvest banana fruit. RESULTS: In this study, exogenous melatonin treatment could significantly reduce the incidence of anthracnose in ripe yellow banana fruit and delay fruit senescence. However, melatonin treatment did not affect the growth of Colletotrichum musae in vitro. Transcriptomic analysis of banana peel showed that 339 genes were up-regulated and 241 were down-regulated in the peel after melatonin treatment, compared with the control. Based on GO terms and KEGG pathway, these up-regulated genes were mainly categorized into signal transduction, cell wall formation, secondary metabolism, volatile compounds synthesis and response to stress, which might be related to the anti-anthracnose of banana fruit induced by melatonin treatment. This view was also supported by the increase of volatile compounds, cell wall components and IAA content in the melatonin-treated fruit peel via the metabolomic analysis. After melatonin treatment, auxin, ethylene and mitogen-activated protein kinase (MAPK) signaling pathways were enhanced, which might be involved in the enhanced fruit resistance by regulating physiological characteristics, disease-resistant proteins and metabolites. CONCLUSIONS: Our results provide a better understanding of the molecular processes in melatonin treatment delaying banana fruit senescence and anthracnose incidence.


Assuntos
Colletotrichum/fisiologia , Genes de Plantas , Melatonina/metabolismo , Metaboloma , Musa/microbiologia , Doenças das Plantas/microbiologia , Transcriptoma , Colletotrichum/efeitos dos fármacos , Frutas/microbiologia , Perfilação da Expressão Gênica , Melatonina/administração & dosagem , Metabolômica , Musa/genética
11.
Plant Dis ; 103(10): 2577-2586, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31347945

RESUMO

Xanthomonas arboricola pv. juglandis is the etiologic agent of important walnut (Juglans regia L.) diseases, causing severe fruit drop and high economic losses in walnut production regions. Rapid diagnostics and knowledge of bacterial virulence fitness are key to hinder disease progression and apply timely phytosanitary measures. This work describes an X. arboricola pv. juglandis-specific real-time quantitative PCR (qPCR) using X. arboricola pv. juglandis-specific DNA markers to quantify the bacterial load in infected walnut plant tissues. Method validation was achieved using calibration curves obtained with serial dilutions of X. arboricola pv. juglandis chromosomal DNA and standard curves obtained from walnut samples spiked with X. arboricola pv. juglandis cells. High correlations (R2 > 0.990 and > 0.995) and low limits of detection (35 chromosomes/qPCR reaction and 2.7 CFU/qPCR reaction) were obtained for both markers considering the calibration and standard curves, respectively. Assessment of qPCR repeatability, reproducibility, and specificity allowed us to demonstrate the reliability and consistency of the method. Furthermore, in planta quantification of X. arboricola pv. juglandis bacterial load using infected walnut fruit samples showed a higher detection resolution compared with standard PCR detection. By allowing quantification of virulence fitness of distinct X. arboricola pv. juglandis strains in planta, the proposed qPCR method may contribute to assertive risk assessment of walnut diseases caused by X. arboricola pv. juglandis and ultimately help to improve phytosanitary practices.


Assuntos
Carga Bacteriana , Juglans , Reação em Cadeia da Polimerase em Tempo Real , Xanthomonas , Frutas/microbiologia , Juglans/microbiologia , Reprodutibilidade dos Testes
12.
Food Chem ; 299: 125117, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31288164

RESUMO

This work evaluated nutritional and organoleptic properties of murta, a Chilean native berry, impregnated with Lactobacillus casei var. rhamnosus and dehydrated by different methods: freeze- (FD), convective- (CD) and vacuum- (VD) drying. Scanning electron microscopy revealed that L. casei localized at the peduncle and near the peduncle of the impregnated fruit. Murta enriched with probiotics contained higher L. casei viable counts after dehydration with FD compared to CD and VD methods. Overall, drying resulted in a decrease in crude fibre and phenolic compounds, which was attributed to L. casei metabolic activity suggesting that murta berries could act as prebiotics for L. casei. Among drying methods, L. casei enriched FD murta presented less alterations in the microstructure, less drying-induced damage and obtained a higher sensory acceptability score than CD and VD murta. Taken together, these results will contribute to the development of functional foods from regional products improving local economy.


Assuntos
Frutas/química , Lactobacillus rhamnosus , Myrtaceae/química , Chile , Dessecação , Fibras na Dieta/análise , Liofilização , Frutas/microbiologia , Humanos , Lactobacillus rhamnosus/crescimento & desenvolvimento , Myrtaceae/microbiologia , Fenóis/análise , Prebióticos , Probióticos , Sensação , Vácuo
13.
Food Chem ; 299: 125109, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31295635

RESUMO

The aim of this research is to develop, characterize and utilize a multi-layer antibacterial film using chitosan (CS) and sodium alginate (SA) as biopolymers and cinnamon essential oil (CEO) as main antibacterial ingredients. The dense cross-section of SA layer in the scanning electron microscopy (SEM) analysis verified that layer-by-layer method improved physical and mechanical properties of CS-CEO single layer film. The thermogravimetric (TGA) and fourier transform infrared (FT-IR) analysis indicated that the layer-by-layer method changed the intermolecular interaction and the thermal stability. Importantly, the multi-layer film exhibited more sustained release and higher retention rate of CEO compared CS-CEO single layer film. The multi-layer coating showed a more significant and lasting inhibition of penicillium expansion which further demonstrated that the layer-by-layer method improved the release and retention of CEO in the multiphased system. To summarize, the multilayer film system is a promising controllable release system for loading essential oils.


Assuntos
Antifúngicos/farmacologia , Cinnamomum zeylanicum/química , Malus/microbiologia , Óleos Voláteis/farmacologia , Penicillium/efeitos dos fármacos , Alginatos/química , Antifúngicos/química , Quitosana/química , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacologia , Frutas/efeitos dos fármacos , Frutas/microbiologia , Malus/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Óleos Voláteis/farmacocinética , Penicillium/patogenicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Termogravimetria
14.
Food Chem ; 299: 125116, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31295637

RESUMO

The effects of exogenous melatonin treatment on the enzymatic browning and nutritional quality of fresh-cut pear fruit were investigated. Fresh-cut fruit soaked with 0, 0.05, 0.1 and 0.5 mM melatonin were stored at 4 °C. Our results showed that 0.1 mM melatonin treatment was optimal for reducing the surface browning and maintaining the titratable acidity of the fresh-cut fruit, which significantly decreased MDA and H2O2 contents and the growth of microorganism, enhanced total phenolic content and antioxidant capacity, and delayed the reduction of ascorbic acid. Furthermore, melatonin treatment at 0.1 mM decreased the expression of genes involving in enzymatic browning pathway including POD, PPO1, PPO5 and LOX1, and reduced PPO activity. Moreover, this treatment increased the expression of PAL and CHS, and enhanced PAL and CHS activities. These results showed that melatonin treatment might be a promising strategy to alleviate browning and improve the nutritional quality of fresh-cut pear fruit.


Assuntos
Frutas/efeitos dos fármacos , Melatonina/farmacologia , Valor Nutritivo , Pyrus/efeitos dos fármacos , Antioxidantes/análise , Antioxidantes/metabolismo , Ácido Ascórbico/análise , Ácido Ascórbico/metabolismo , Armazenamento de Alimentos , Frutas/química , Frutas/metabolismo , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/metabolismo , Malondialdeído/análise , Malondialdeído/metabolismo , Fenóis/análise , Pyrus/química , Pyrus/genética , Pyrus/metabolismo
15.
Microbiol Res ; 226: 27-33, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284941

RESUMO

Postbloom fruit drop (PFD), caused mainly by Colletotrichum abscissum, is one of the most severe citrus diseases and can causes up to 80% fruit loss in favorable climatic conditions. According to the literature, other Colletotrichum species colonize hosts using distinct strategies: intracellular hemibiotrophic or subcuticular intramural necrotrophic colonization. However, so far, for C. abscissum only the necrotrophic stage has been described and some aspects remain unclear in PFD disease cycle. To better understand the disease cycle, microscopy studies could be applied. However, even using eGFP strains (expressing green fluorescent protein), the results are unclear due to the autofluorescence of citrus leaves. To eliminate this problem and to study the interaction between C. abscissum-citrus we used a destaining and staining methodologies, and we observed that in leaves, even applying injury before inoculation, C. abscissum does not colonize adjacent tissues. Apparently, in the leaves the fungus only uses the nutrients exposed in the artificial lesions for growth, and then produces large amount of spores. However, in flowers, C. abscissum penetrated and colonized the tissues of the petals 12 h after inoculation. In the early stages of infection, we observed the development of primary biotrophic hyphae, suggesting this species as a hemibiotrophic fungus, with a short biotrophic phase during flower colonization followed by dominant necrotrophic colonization. In conclusion, the use of an eGFP strain of C. abscissum and a different methodology of destaining and staining allowed a better understanding of the morphology and mechanisms used by this citrus pathogen to colonize the host.


Assuntos
Citrus/microbiologia , Colletotrichum/citologia , Colletotrichum/crescimento & desenvolvimento , Colletotrichum/patogenicidade , Doenças das Plantas/microbiologia , Flores/microbiologia , Frutas/microbiologia , Proteínas de Fluorescência Verde , Interações Hospedeiro-Patógeno , Hifas/citologia , Hifas/crescimento & desenvolvimento , Microscopia/métodos , Microscopia Confocal/métodos , Folhas de Planta , Esporos Fúngicos/citologia
16.
J Sci Food Agric ; 99(13): 5784-5791, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31162677

RESUMO

BACKGROUND: The use of byproducts such as rejected plantain with final disposition problems and conversion processes with 'green' technologies are important research topics. Bioethanol production from crops with a high content of fermentable sugars is an alternative to that from traditional crops (corn and sugar cane). The aim of this work was to study the use of whole (peel and pulp) unripe plantain (WP) for bioethanol production. RESULTS: Lab-scale liquefaction and saccharification of both materials released mainly three carbohydrates, glucose (9.02 mg g-1 ), maltose (0.45 mg g-1 ) and xylose (0.25 mg g-1 ). The WP saccharification required the use of pectinase and cellulase because of the high amounts of pectin and cellulose associated with the peel. Fermentation for 11 h produced similar ethanol concentration for both samples, but at the end of fermentation (32 h), the ethanol production was higher in the WP (58.6 mL L-1 ) compared with the plantain pulp (PP) (45.5 mL L-1 ). The theoretical ethanol yield was lower with WP (67%) than with PP (90%). CONCLUSION: WP can be an alternative raw material for bioethanol production. © 2019 Society of Chemical Industry.


Assuntos
Biocombustíveis/análise , Etanol/metabolismo , Microbiologia Industrial/métodos , Musa/química , Saccharomyces cerevisiae/metabolismo , Resíduos/análise , Biocatálise , Celulase/química , Etanol/análise , Fermentação , Frutas/química , Frutas/microbiologia , Musa/microbiologia , Poligalacturonase/química
17.
Plant Dis ; 103(8): 1889-1901, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161920

RESUMO

Apple fruit spot disease has caused serious economic losses for years in China since the widespread application of fruit bagging in production. Although the three genera Trichothecium, Alternaria, and Acremonium have been reported to be the causal agents, studies on the disease etiology and pathogen biology are still sparse. Here, we report characterization of eight fungal isolates from lesions on 126 symptomatic fruit samples collected in Shaanxi Province, China. Pathogenicity of the isolates was assessed. DNA sequences were obtained at four loci, including D1/D2 domains of the large-subunit nrRNA gene, internal transcribed spacer regions 1 and 2, 5.8S nrDAN gene, a fragment of the actin gene, and a fragment of the ß-tubulin. Based on phylogenetic analysis and morphological features, three new species were found: Acremonium mali, Sarocladium liquanensis, and Sarocladium mali. In addition, we made the first report of Sarocladium terricola as a plant pathogen. Temperature and moisture significantly affected in vitro conidial germination of five Acremonium-like species, and their impact on infection of apple fruit was tested using Acremonium sclerotigenum. Conidia of five species germinated from 15 to 35°C in free water; four of the species had optimum temperature around 25°C, whereas conidia of S. terricola had an optimum temperature of 30°C. Conidial germination rate increased as relative humidity (RH) increased. The five isolates had relatively high conidial germination rates at RH > 97%, with a significant decline at 95% RH. Incidence of infection also increased in proportion to RH. In free water, conidial germination was relatively unaffected by temperature.


Assuntos
Acremonium , Ascomicetos , Frutas , Malus , Acremonium/classificação , Acremonium/fisiologia , Ascomicetos/classificação , Ascomicetos/fisiologia , China , Frutas/microbiologia , Malus/microbiologia , Filogenia , Temperatura Ambiente
18.
J Food Sci ; 84(6): 1494-1500, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31059142

RESUMO

Strawberry is a healthy fruit with numerous health-benefit compounds. Unfortunately, it is highly perishable and occasionally can be contaminated with foodborne pathogens. The overall goal of this study is to evaluate pulsed light (PL) processing for disinfection of strawberries, extension of shelf life, and preservation of quality attributes and compounds that are beneficial to health. Preliminary screening of PL conditions based on visual appearance of strawberries was conducted, and 3 PL treatments were identified for full evaluation. Salmonella inoculum was artificially deposited onto the skin of strawberries via spot-inoculation or dip-inoculation. The 3 PL treatments slightly reduced the level of inoculated Salmonella on strawberries, ranging from approximately 0.4 to 0.8 log reduction. They also slowed down the visible mold development on strawberries by 2 to 4 days compared with the untreated control. Regarding the natural yeasts and molds, the quality attributes (weight loss and firmness), and the bioactive compounds (total anthocyanin, total phenolics, and total antioxidant activity). The 3 PL treatment showed no significant or negligible difference comparing to the control group. Overall, the 3 PL treatments demonstrated potential in extending the shelf life of strawberries. The quality attributes or the bioactive compounds of strawberries showed no significant or minimal change after these PL treatments. PRACTICAL APPLICATION: Pulsed light (PL) processing for strawberry decontamination and shelf life extension was evaluated. Results demonstrated that PL processing could have the potency to improve strawberry shelf life without significantly affecting the quality and bioactive compounds of strawberries.


Assuntos
Qualidade dos Alimentos , Inocuidade dos Alimentos/métodos , Armazenamento de Alimentos/métodos , Fragaria , Frutas/microbiologia , Luz , Antocianinas/análise , Antioxidantes/análise , Descontaminação/métodos , Microbiologia de Alimentos/métodos , Frutas/química , Fungos/crescimento & desenvolvimento , Fenóis/análise , Salmonella/crescimento & desenvolvimento
19.
J Agric Food Chem ; 67(24): 6725-6735, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31117506

RESUMO

Jasmonic acid (JA)- and ethylene-mediated signaling pathways are reported to have synergistic effects on inhibiting gray mold. The present study aimed to explain the role of ethylene perception in methyl jasmonate (MeJA)-mediated immune responses. Results showed that exogenous MeJA enhanced disease resistance, accompanied by the induction of endogenous JA biosynthesis and ethylene production, which led to the activation of the phenolic metabolism pathway. Blocking ethylene perception using 1-methylcyclopropene (1-MCP) either before or after MeJA treatment could differently weaken the disease responses induced by MeJA, including suppressing the induction of ethylene production and JA contents and reducing activities of lipoxygenase and allene oxide synthase compared to MeJA treatment alone. Consequently, MeJA-induced elevations in the total phenolic content and the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, 4-coumarate:coenzyme A ligase, and peroxidase were impaired by 1-MCP. These results suggested that ethylene perception participated in MeJA-mediated immune responses in tomato fruit.


Assuntos
Acetatos/imunologia , Botrytis/fisiologia , Ciclopentanos/imunologia , Etilenos/imunologia , Lycopersicon esculentum/imunologia , Oxilipinas/imunologia , Doenças das Plantas/imunologia , Reguladores de Crescimento de Planta/imunologia , Resistência à Doença , Frutas/imunologia , Frutas/microbiologia , Regulação da Expressão Gênica de Plantas , Lycopersicon esculentum/genética , Lycopersicon esculentum/microbiologia , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Transcinamato 4-Mono-Oxigenase/genética , Transcinamato 4-Mono-Oxigenase/imunologia
20.
J Agric Food Chem ; 67(24): 6748-6756, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31136167

RESUMO

A 11 kDa antifungal protein FEAP was purified from buckwheat ( Fagopyrum esculentum) seed extract with a procedure involving (NH4)2SO4 precipitation and chromatography on SP-Sepharose, Affi-gel blue gel, Mono S, and Superdex peptide. Its N-terminal sequence was AQXGAQGGGAT, resembling those of buckwheat peptides Fα-AMP1 and Fα-AMP2. FEAP exhibited thermostability (20-100 °C) and acid resistance (pH 1-5). Its antifungal activity was retained in the presence of 10-150 mmol/L of K+, Mn2+, or Fe3+ ions, 10-50 mmol/L of Ca2+ or Mg2+ ions, and 50% methanol, 50% ethanol, 50% isopropanol, or 50% chloroform. Its half-maximal inhibitory concentrations toward spore germination and mycelial growth in Botrytis cinerea were 79.9 and 236.7 µg/mL, respectively. Its antifungal activity was superior to the fungicide cymoxanil mancozeb (248.1 µg/mL). FEAP prevented B. cinerea from infecting excised leaves, intact leaves, and isolated fruits of cherry tomato. Its mechanism involved induction of an increase in cell membrane permeability and a decrease in mitochondrial membrane potential.


Assuntos
Botrytis/fisiologia , Fagopyrum/química , Fungicidas Industriais/farmacologia , Lycopersicon esculentum/microbiologia , Doenças das Plantas/prevenção & controle , Proteínas de Plantas/farmacologia , Motivos de Aminoácidos , Botrytis/efeitos dos fármacos , Frutas/microbiologia , Fungicidas Industriais/química , Fungicidas Industriais/isolamento & purificação , Doenças das Plantas/microbiologia , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação
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