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1.
Arch Virol ; 166(10): 2881-2885, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34338875

RESUMO

Here, we describe a novel mycovirus, tentatively designated as "Botryosphaeria dothidea mitovirus 3" (BdMV3), isolated from Botryosphaeria dothidea strain FJ, which causes pear ring rot disease in Fujian Province, China. The complete genome nucleotide sequence of BdMV3 is 2538 nt in length and contains a single 2070-nt open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) of 689 amino acids (aa) using the fungal mitochondrial genetic code. BLASTp analysis revealed that the RdRp of BdMV3 shares 28.91%-69.36% sequence identity (query sequence coverage more than 90%) with those of members of the genus Mitovirus, with the highest sequence identity of 69.36% and 68.79% to the corresponding RdRp aa sequences of Rhizoctonia solani mitovirus 10 and Macrophomina phaseolina mitovirus 4, respectively. Phylogenetic analysis based on RdRp aa sequences indicated that BdMV3 is a new member of the genus Mitovirus in the family Mitoviridae.


Assuntos
Ascomicetos/virologia , Genoma Viral/genética , Doenças das Plantas/microbiologia , Pyrus/microbiologia , Vírus de RNA/genética , Sequência de Aminoácidos , China , Micovírus/classificação , Micovírus/genética , Fases de Leitura Aberta/genética , Filogenia , Vírus de RNA/classificação , RNA Viral/genética , RNA Polimerase Dependente de RNA/genética
2.
Molecules ; 26(11)2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34198776

RESUMO

In this paper, peptide conjugates were designed and synthesized by incorporating the antimicrobial undecapeptide BP16 at the C- or N-terminus of the plant defense elicitor peptide flg15, leading to BP358 and BP359, respectively. The evaluation of their in vitro activity against six plant pathogenic bacteria revealed that BP358 displayed MIC values between 1.6 and 12.5 µM, being more active than flg15, BP16, BP359, and an equimolar mixture of BP16 and flg15. Moreover, BP358 was neither hemolytic nor toxic to tobacco leaves. BP358 triggered the overexpression of 6 out of the 11 plant defense-related genes tested. Interestingly, BP358 inhibited Erwinia amylovora infections in pear plants, showing slightly higher efficacy than the mixture of BP16 and flg15, and both treatments were as effective as the antibiotic kasugamycin. Thus, the bifunctional peptide conjugate BP358 is a promising agent to control fire blight and possibly other plant bacterial diseases.


Assuntos
Erwinia amylovora/crescimento & desenvolvimento , Proteínas Citotóxicas Formadoras de Poros/síntese química , Pyrus/crescimento & desenvolvimento , Erwinia amylovora/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Pyrus/microbiologia
3.
Appl Environ Microbiol ; 87(15): e0004821, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34020936

RESUMO

Crop-associated microbiota are a key factor affecting host health and productivity. Most crops are grown within heterogeneous landscapes, and interactions between management practices and landscape context often affect plant and animal biodiversity in agroecosystems. However, whether these same factors typically affect crop-associated microbiota is less clear. Here, we assessed whether orchard management strategies and landscape context affected bacterial and fungal communities in pear (Pyrus communis) flowers. We found that bacteria and fungi responded differently to management schemes. Organically certified orchards had higher fungal diversity in flowers than conventional or bio-based integrated pest management (IPM) orchards, but organic orchards had the lowest bacterial diversity. Orchard management scheme also best predicted the distribution of several important bacterial and fungal genera that either cause or suppress disease; organic and bio-based IPM best explained the distributions of bacterial and fungal genera, respectively. Moreover, patterns of bacterial and fungal diversity were affected by interactions between management, landscape context, and climate. When examining the similarity of bacterial and fungal communities across sites, both abundance- and taxon-related turnovers were mediated primarily by orchard management scheme and landscape context and, specifically, the amount of land in cultivation. Our study reveals local- and landscape-level drivers of floral microbiome structure in a major fruit crop, providing insights that can inform microbiome management to promote host health and high-yielding quality fruit. IMPORTANCE Proper crop management during bloom is essential for producing disease-free tree fruit. Tree fruits are often grown in heterogeneous landscapes; however, few studies have assessed whether landscape context and crop management affect the floral microbiome, which plays a critical role in shaping plant health and disease tolerance. Such work is key for identification of tactics and/or contexts where beneficial microbes proliferate and pathogenic microbes are limited. Here, we characterize the floral microbiome of pear crops in Washington State, where major production occurs in intermountain valleys and basins with variable elevation and microclimates. Our results show that both local-level (crop management) and landscape-level (habitat types and climate) factors affect floral microbiota but in disparate ways for each kingdom. More broadly, these findings can potentially inform microbiome management in orchards for promotion of host health and high-quality yields.


Assuntos
Agricultura/métodos , Flores/microbiologia , Microbiota , Pyrus/microbiologia , Bactérias/classificação , Bactérias/genética , Produtos Agrícolas/microbiologia , DNA Bacteriano , DNA Fúngico , Fungos/classificação , Fungos/genética , Washington
4.
Toxins (Basel) ; 13(4)2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33807312

RESUMO

Ochratoxin A (OTA) usually contaminates agricultural products such as grapes, oatmeal, coffee and spices. Light was reported as an effective strategy to control spoilage fungi and mycotoxins. This research investigated the effects of light with different wavelengths on the growth and the production of OTA in Aspergillus ochraceus and Aspergillus carbonarius. The results showed that the growth of both fungi were extremely inhibited by UV-B. Short-wavelength (blue, violet) significantly inhibited the production of OTA in both fungi, while the inhibitory effect of white was only demonstrated on A. ochraceus. These results were supported by the expression profiles of OTA biosynthetic genes of A. ochraceus and A. carbonarius. To clarify, the decrease in OTA production is induced by inhibition or degradation; therefore, the degradation of OTA under different wavelengths of light was tested. Under UV-B, the degradation rate of 10 µg/mL OTA standard pure-solution samples could reach 96.50% in 15 days, and the degradation effect of blue light was relatively weak. Furthermore, infection experiments of pears showed that the pathogenicity of both fungi was significantly decreased under UV-B radiation. Thus, these results suggested that light could be used as a potential target for strategies in the prevention and control of ochratoxigenic fungi.


Assuntos
Aspergillus ochraceus/efeitos da radiação , Aspergillus/efeitos dos fármacos , Frutas/microbiologia , Ocratoxinas/biossíntese , Pyrus/microbiologia , Raios Ultravioleta , Aspergillus/genética , Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Aspergillus ochraceus/genética , Aspergillus ochraceus/crescimento & desenvolvimento , Aspergillus ochraceus/metabolismo , Microbiologia de Alimentos , Regulação Fúngica da Expressão Gênica , Fatores de Tempo
5.
PLoS One ; 16(4): e0250203, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33886638

RESUMO

Currently, one of the most important challenges is to provide sufficient and affordable food and energy for a fast-growing world population, alongside preserving natural habitats and maintaining biodiversity. About 35% of the global food production depends on animals for pollination. In recent years, an alarming worldwide decline in pollinators has been reported, putting our food production under additional pressure. Therefore, there is an urgent need to find sustainable ways to ensure this crucial ecosystem service. Recent studies have shown that floral nectar is generally colonized by microorganisms, specifically yeasts and bacteria, which may alter nectar chemistry and enhance attraction of pollinators. In this study, we investigated changes in pollinator foraging behavior and pollination success in European pear (Pyrus communis L.) cultivars 'Regal Red' and 'Sweet Sensation' (red sports of 'Doyenné de Comice') after flower inoculation with the typical nectar-inhabiting microorganisms Metschnikowia reukaufii and Acinetobacter nectaris, and a combination of both. Pollination success was monitored by measuring the number of flower visits, fruit set and seed set in two consecutive years, 2019 and 2020. Results revealed that application of a mixture of M. reukaufii and A. nectaris resulted in significantly higher visitation rates of honeybees and hoverflies. By contrast, no effects on flower visits were found when yeasts and bacteria were applied separately. Fruit set and seed set were not significantly affected by any of the inoculation treatments. The only factors affecting fruit set were initial number of flower clusters on the trees and the year. The absence of treatment effects can most likely be attributed to the fact that pollination was not a limiting factor for fruit set in our experiments. Altogether, our results show that inoculation of flowers with nectar microbes can modify pollinator foraging patterns, but did not lead to increased pollination success under the conditions tested.


Assuntos
Flores/microbiologia , Néctar de Plantas , Polinização , Pyrus/microbiologia , Animais , Abelhas , Frutas
6.
Int J Food Microbiol ; 345: 109129, 2021 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-33711686

RESUMO

The production of pome fruits as pears and apples, as well as their derived industries, is of great economic importance in North Patagonia. The elaboration of fermented beverages as cider or perry has evidenced a substantial diversification during the last years, with the evaluation of different fruit varieties, yeast starters and technological changes. In this work, two cryotolerant yeasts belonging to the species Saccharomyces uvarum were evaluated at laboratory and pilot scale in sterile and no-sterile pear must. One of the strains was originally isolated from apple chicha (strain NPCC1314) and the other from apple cider (strain NPCC1420) in Patagonia. Both physicochemical and sensory features of the fermented products were evaluated. Both strains were able to successfully complete the fermentations, although strain NPCC1420 showed the better kinetic properties including a faster sugar consumption than the strain NPCC1314. Both strains showed excellent implantation capacity, but the fermented products showed different chemical profiles. The perry fermented with the strain NPCC1314 was characterized by better sensory attributes as assessed by trained panelists and a greater acceptance for untrained public than the same fermented with the strain NPCC1420. The two strains were able to consume sorbitol, both in pear must and in agar-plates supplemented with sorbitol as the sole carbon source. This ability is described for the first time in S. uvarum, at least for the two strains evaluated in this work.


Assuntos
Bebidas Alcoólicas/análise , Alimentos e Bebidas Fermentados/microbiologia , Pyrus/microbiologia , Saccharomyces/metabolismo , Argentina , Reatores Biológicos , Chile , Fermentação , Frutas/química , Frutas/microbiologia , Malus/microbiologia , Saccharomyces/isolamento & purificação , Leveduras/classificação , Leveduras/isolamento & purificação
7.
Planta ; 253(4): 78, 2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33715081

RESUMO

MAIN CONCLUSION: The in vitro application of rhizosphere microorganisms led to a higher rooting percentage in Pyrus Py12 rootstocks and increased plant growth of Pyrus Py170 and Prunus RP-20. The rooting of fruit tree rootstocks is the most challenging step of the in vitro propagation process. The use of rhizosphere microorganisms to promote in vitro rooting and plant growth as an alternative to the addition of chemical hormones to culture media is proposed in the present study. Explants from two Pyrus (Py170 and Py12) rootstocks and the Prunus RP-20 rootstock were inoculated with Pseudomonas oryzihabitans PGP01, Cladosporium ramotenellum PGP02 and Phoma sp. PGP03 following two different methods to determine their effects on in vitro rooting and plantlet growth. The effects of the microorganisms on the growth of fully developed Py170 and RP-20 plantlets were also studied in vitro. All experiments were conducted using vermiculite to simulate a soil system in vitro. When applied to Py12 shoots, which is a hard-to-root plant material, both C. ramotenellum PGP02 and Phoma sp. PGP03 fungi were able to increase the rooting percentage from 56.25% to 100% following auxin indole-3-butyric acid (IBA) treatment. Thus, the presence of these microorganisms clearly improved root development, inducing a higher number of roots and causing shorter roots. Better overall growth and improved stem growth of treated plants was observed when auxin treatment was replaced by co-culture with microorganisms. A root growth-promoting effect was observed on RP-20 plantlets after inoculation with C. ramotenellum PGP02, while P. oryzihabitans PGP01 increased root numbers for both Py170 and RP-20 and increased root growth over stem growth for RP-20. It was also shown that the three microorganisms P. oryzihabitans PGP01, C. ramotenellum PGP02 and Phoma sp. PGP03 were able to naturally produce auxin, including indole-3-acetic acid (IAA), at different levels. Overall, our results demonstrate that the microorganisms P. oryzihabitans PGP01 and C. ramotenellum PGP02 had beneficial effects on in vitro rooting and plantlet growth and could be applied to in vitro tissue culture as a substitute for IBA.


Assuntos
Cladosporium/fisiologia , Raízes de Plantas/fisiologia , Prunus/fisiologia , Pseudomonas/fisiologia , Pyrus/fisiologia , Phoma/fisiologia , Raízes de Plantas/microbiologia , Prunus/microbiologia , Pyrus/microbiologia , Rizosfera , Microbiologia do Solo
8.
Molecules ; 26(3)2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-33573272

RESUMO

Pears (Pyrus communis L.) cv. Packham's Triumph are very traditional for human consumption, but pear is a highly perishable climacteric fruit with a short shelf-life affected by several diseases with a microbial origin. In this study, a protective effect on the quality properties of pears was evidenced after the surface application of chitosan-Ruta graveolens essential oil coatings (CS + RGEO) in four different concentrations (0, 0.5, 1.0 and 1.5 %, v/v) during 21 days of storage under 18 °C. After 21 days of treatment, a weight loss reduction of 10% (from 40.2 ± 5.3 to 20.3 ± 3.9) compared to the uncoated pears was evident with CS + RGEO 0.5%. All the fruits' physical-chemical properties evidenced a protective effect of the coatings. The maturity index increased for all the treatments. However, the pears with CS + RGEO 1.5% were lower (70.21) than the uncoated fruits (98.96). The loss of firmness for the uncoated samples was higher compared to the coated samples. The pears' most excellent mechanical resistance was obtained with CS + RGEO 0.5% after 21 days of storage, both for compression resistance (7.42 kPa) and force (22.7 N). Microbiological studies demonstrated the protective power of the coatings. Aerobic mesophilic bacteria and molds were significantly reduced (in 3 Log CFU/g compared to control) using 15 µL/mL of RGEO, without affecting consumer perception. The results presented in this study showed that CS + RGEO coatings are promising in the post-harvest treatment of pears.


Assuntos
Quitosana/química , Conservação de Alimentos/métodos , Óleos Voláteis/farmacologia , Pyrus/química , Quitosana/farmacologia , Resposta ao Choque Frio/efeitos dos fármacos , Frutas/química , Fungos/efeitos dos fármacos , Humanos , Óleos Voláteis/química , Óleos Vegetais/química , Pyrus/efeitos dos fármacos , Pyrus/microbiologia , Ruta/química , Temperatura
9.
J Sci Food Agric ; 101(11): 4473-4480, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33432579

RESUMO

BACKGROUND: The greatest hurdle to commercial marketing of fresh-cut fruits and vegetables is limited shelf life due to microbial hazards and quality deterioration. Atmospheric cold plasma (ACP) is an emerging non-thermal technology with significant potential to improve the safety and storability of fresh products. The objective of this study was to evaluate the effects of ACP, generated in sealed packaging, on the qualitative, metabolic and microbial stability of fresh-cut pears during simulated cold storage. RESULTS: ACP treatments were effective in inhibiting the growth of mesophilic aerobic bacteria, yeast and mold, particularly CP3 (65 kV, 1 min), which could prolong shelf life to the greatest extent. While decontamination was not always associated with an increase in plasma intensity. Moreover, at 65 kV for 1 min, ACP treatment had the potential to retard respiration, and maintain organoleptic properties and other quality attributes. Additionally, peroxidase and pectin methylesterase (PME) activities were reduced immediately after treatments. These effects were dependent on treatment voltage and time, while a subsequent recovery in activity was only observed for PME. CONCLUSION: The results obtained from this study will contribute to an understanding of the effects of in-package ACP treatments on the storability and microbial safety of fresh-cut pears. This knowledge could be beneficial in reducing quality losses for fresh-cut pears and the preservation of other products. © 2021 Society of Chemical Industry.


Assuntos
Conservação de Alimentos/métodos , Frutas/química , Gases em Plasma/farmacologia , Pyrus/metabolismo , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Hidrolases de Éster Carboxílico/metabolismo , Embalagem de Alimentos , Conservação de Alimentos/instrumentação , Frutas/metabolismo , Frutas/microbiologia , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Peroxidase/metabolismo , Proteínas de Plantas/metabolismo , Pyrus/química , Pyrus/microbiologia , Controle de Qualidade
10.
Food Microbiol ; 95: 103681, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33397614

RESUMO

Penicillium expansum is the main cause of Blue Mold Decay, which is the economically most significant postharvest disease on fruits. It occurs especially on pomaceous fruits such as apples and pears but also on a wide range of other fruits such as grapes or strawberries. Besides its negative economic effects on the industry, the fungus is also of health concern as it produces patulin, a mycotoxin known to provoke harmful effects in humans. A specific and rapid detection of this fungus therefore is required. In the current study, a loop-mediated isothermal amplification (LAMP) assay was developed and optimized for the species-specific detection of P. expansum. The assay showed high specificity during tests with genomic DNA of 187 fungal strains. The detection limit of the developed assay was 25 pg genomic DNA of P. expansum per reaction. The assay was successfully applied for the detection of the fungus on artificially contaminated apples, grapes, apple juice, apple puree, and grape juice. The developed assay is a promising tool for rapid, sensitive, specific, and cost-efficient detection of P. expansum in quality control applications in the food and beverage industry.


Assuntos
Frutas/microbiologia , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Penicillium/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Fragaria/microbiologia , Sucos de Frutas e Vegetais/microbiologia , Malus/microbiologia , Patulina/metabolismo , Penicillium/classificação , Penicillium/genética , Penicillium/metabolismo , Pyrus/microbiologia , Vitis/microbiologia
11.
Planta ; 253(2): 32, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33439355

RESUMO

MAIN CONCLUSION: Genome-wide identification, tissue-specific and stress expression analyses and functional characterization of PbrATG8s genes were conducted and the role of PbrATG8c in Botryosphaeria dothidea resistance was further investigated. Autophagy plays an important role in plant growth, development and stress tolerance. ATG8 has been reported to be an autophagy marker in many species. However, there is little information regarding ATG8 family members in pear (Pyrus bretschneideri Rehd). We performed a genome-wide analysis and identified nine PbrATG8 gene family members in pear. Phylogenetic analysis showed that PbrATG8 genes clustered into four major groups (Groups I-IV). Eight PbrATG8 genes were successfully mapped to 6 of the 17 chromosomes of the pear genome. The synteny results showed that two pairs are collinear. Gene expression data showed that all genes were differentially expressed in a range of pear tissues. Transcript analysis of PbrATG8 genes under dehydration, salt and pathogen infection stresses revealed that PbrATG8c responded to all test stresses. The PbrATG8c protein was localized in the nucleus and membrane. The silencing of PbrATG8c decreased the resistance to Botryosphaeria dothidea in pear. This study provides insights and rich resources for subsequent investigations of autophagy in pear.


Assuntos
Família da Proteína 8 Relacionada à Autofagia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Pyrus , Ascomicetos , Autofagia/genética , Família da Proteína 8 Relacionada à Autofagia/genética , Família da Proteína 8 Relacionada à Autofagia/metabolismo , Resistência à Doença/genética , Evolução Molecular , Perfilação da Expressão Gênica , Família Multigênica , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Pyrus/genética , Pyrus/microbiologia
12.
ACS Appl Mater Interfaces ; 13(2): 2179-2188, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33405501

RESUMO

The need to increase agricultural yield has led to an extensive use of antibiotics against plant pathogens, which has resulted in the emergence of resistant strains. Therefore, there is an increasing demand for new methods, preferably with lower chances of developing resistant strains and a lower risk to the environment or public health. Many Gram-negative bacterial pathogens use quorum sensing, a population-density-dependent regulatory mechanism, to monitor the secretion of N-acyl-homoserine lactones (AHLs) and pathogenicity. Therefore, quorum sensing represents an attractive antivirulence target. AHL lactonases hydrolyze AHLs and have potential antibacterial properties; however, their use is limited by thermal instability and durability, or low activity. Here, we demonstrate that an AHL lactonase from the phosphotriesterase-like lactonase family exhibits high activity with the AHL secreted from the plant pathogen Erwinia amylovora and attenuates infection in planta. Using directed enzyme evolution, we were able to increase the enzyme's temperature resistance (T50, the temperature at which 50% of the activity is retained) by 8 °C. Then, by performing enzyme encapsulation in nanospherical capsules composed of tertbutoxycarbonyl-Phe-Phe-OH peptide, the shelf life was extended for more than 5 weeks. Furthermore, the encapsulated and free mutant were able to significantly inhibit up to 70% blossom's infection in the field, achieving the same efficacy as seen with antibiotics commonly used today to treat the plant pathogen. We conclude that specific AHL lactonase can inhibit E. amylovora infection in the field, as it degrades the AHL secreted by this plant pathogen. The combination of directed enzyme evolution and peptide nanostructure encapsulation significantly improved the thermal resistance and shelf life of the enzyme, respectively, increasing its potential in future development as antibacterial treatment.


Assuntos
Hidrolases de Éster Carboxílico/farmacologia , Erwinia amylovora/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia , Nanosferas/química , Doenças das Plantas/prevenção & controle , Percepção de Quorum/efeitos dos fármacos , Acil-Butirolactonas/metabolismo , Hidrolases de Éster Carboxílico/administração & dosagem , Hidrolases de Éster Carboxílico/genética , Evolução Molecular Direcionada/métodos , Enzimas Imobilizadas/administração & dosagem , Enzimas Imobilizadas/genética , Enzimas Imobilizadas/farmacologia , Erwinia amylovora/fisiologia , Modelos Moleculares , Peptídeos/química , Doenças das Plantas/microbiologia , Pyrus/microbiologia
13.
BMC Genomics ; 21(1): 612, 2020 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-32894061

RESUMO

BACKGROUND: Lysin motif-containing proteins (LYP), which act as pattern-recognition receptors, play central roles in growth, node formation, and responses to biotic stresses. The sequence of Chinese white pear genome (cv. 'Dangshansuli') along with the seven other species of Rosaceae has already been reported. Although, in these fruit crops, there is still a lack of clarity regarding the LYP family genes and their evolutionary history. RESULTS: In the existing study, eight Rosaceae species i.e., Pyrus communis, Prunus persica, Fragaria vesca, Pyrus bretschneideri, Prunus avium, Prunus mume, Rubus occidentalis, and Malus × domestica were evaluated. Here, we determined a total of 124 LYP genes from the underlined Rosaceae species. While eighteen of the genes were from Chinese white pear, named as PbrLYPs. According to the LYPs structural characteristics and their phylogenetic analysis, those genes were classified into eight groups (group LYK1, LYK2, LYK3, LYK4/5, LYM1/3, LYM2, NFP, and WAKL). Dispersed duplication and whole-genome duplication (WGD) were found to be the most contributing factors of LYP family expansion in the Rosaceae species. More than half of the duplicated PbrLYP gene pairs were dated back to the ancient WGD (~ 140 million years ago (MYA)), and PbrLYP genes have experienced long-term purifying selection. The transcriptomic results indicated that the PbrLYP genes expression was tissue-specific. Most PbrLYP genes showed differential expression in leaves under fungal pathogen infection with two of them located in the plasmalemma. CONCLUSION: A comprehensive analysis identified 124 LYP genes in eight Rosaceae species. Our findings have provided insights into the functions and characteristics of the Rosaceae LYP genes and a guide for the identification of other candidate LYPs for further genetic improvements for pathogen-resistance in higher plants.


Assuntos
Resistência à Doença , Proteínas de Plantas/genética , Proteínas Quinases/genética , Pyrus/genética , Motivos de Aminoácidos , Ascomicetos/patogenicidade , Regulação da Expressão Gênica de Plantas , Lisina/química , Família Multigênica , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Pyrus/classificação , Pyrus/microbiologia
14.
Mol Plant Pathol ; 21(11): 1391-1404, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32969130

RESUMO

Blue mould, caused primarily by Penicillium expansum, is a major threat to the global pome fruit industry, causing multimillion-dollar losses annually. The blue mould fungus negatively affects fruit quality, thereby reducing fresh fruit consumption, and significantly contributes to food loss. P. expansum also produces an array of mycotoxins that are detrimental to human health. Management options are limited and the emergence of fungicide-resistant Penicillium spp. makes disease management difficult, therefore new approaches and tools are needed to combat blue mould in storage. This species profile comprises a comprehensive literature review of this aggressive pathogen associated with pomes (apple, pear, quince), focusing on biology, mechanisms of disease, control, genomics, and the newest developments in disease management. TAXONOMY: Penicillium expansum Link 1809. Domain Eukaryota, Kingdom Fungi, Phylum Ascomycota, Subphylum Pezizomycotina, Class Eurotiomycetes, Subclass: Eurotiomycetidae, Order Eurotiales; Family Trichocomaceae, Genus Penicillium, Species expansum. BIOLOGY: A wide host range necrotrophic postharvest pathogen that requires a wound (e.g., stem pull, punctures, bruises, shoulder cracks) or natural openings (e.g., lenticel, stem end, calyx sinus) to gain ingress and infect. TOXINS: Patulin, citrinin, chaetoglobosins, communesins, roquefortine C, expansolides A and B, ochratoxin A, penitrem A, rubratoxin B, and penicillic acid. HOST RANGE: Primarily apples, European pear, Asian pear, medlar, and quince. Blue mould has also been reported on stone fruits (cherry, plum, peach), small fruits (grape, strawberry, kiwi), and hazel nut. DISEASE SYMPTOMS: Blue mould initially appears as light tan to dark brown circular lesions with a defined margin between the decayed and healthy tissues. The decayed tissue is soft and watery, and blue-green spore masses appear on the decayed area, starting at the infection site and radiating outward as the decayed area ages. DISEASE CONTROL: Preharvest fungicides with postharvest activity and postharvest fungicides are primarily used to control decay. Orchard and packinghouse sanitation methods are also critical components of an integrated pest management strategy. USEFUL WEBSITES: Penn State Tree Fruit Production Guide (https://extension.psu.edu/forage-and-food-crops/fruit), Washington State Comprehensive Tree Fruit (http://treefruit.wsu.edu/crop-protection/disease-management/blue-mold/), The Apple Rot Doctor (https://waynejurick.wixsite.com/applerotdr), penicillium expansum genome sequences and resources (https://www.ncbi.nlm.nih.gov/genome/browse/#!/eukaryotes/11336/).


Assuntos
Genoma Fúngico/genética , Malus/microbiologia , Penicillium/genética , Doenças das Plantas/microbiologia , Pyrus/microbiologia , Rosaceae/microbiologia , Farmacorresistência Fúngica , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Especificidade de Hospedeiro , Micotoxinas/metabolismo , Patulina/metabolismo , Penicillium/efeitos dos fármacos , Penicillium/patogenicidade , Doenças das Plantas/prevenção & controle
15.
J Bacteriol ; 202(22)2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-32839177

RESUMO

The Gram-negative enterobacterium Erwinia amylovora causes fire blight disease in apple and pear trees. Lipopolysaccharides and the exopolysaccharide amylovoran are essential E. amylovora virulence factors. We found that mutations in rfbX disrupted amylovoran production and virulence in apple fruits and tree shoots and that the deletion of yibD suppressed the rfbX mutant phenotype. The level of expression of yibD was about 10-fold higher in the ΔrfbX mutant than the wild type. A forward genetic suppressor screen in the ΔrfbX mutant uncovered multiple mutations in yibD and supported the conclusion that the virulence defect of rfbX mutants is due to reduced amylovoran production. The yibD and rfbX genes are expressed as a two-gene operon, yibD rfbX The rfbX gene encodes a previously uncharacterized putative polysaccharide subunit transporter, while yibD encodes a predicted glycosyltransferase. Mutation of rfbX did not have a detectable effect on lipopolysaccharide patterns; however, the overexpression of yibD in both the wild-type and ΔyibD ΔrfbX genetic backgrounds disrupted both amylovoran and lipopolysaccharide production. Additionally, the overexpression of yibD in the ΔyibD ΔrfbX mutant inhibited bacterial growth in amylovoran-inducing medium. This growth inhibition phenotype was used in a forward genetic suppressor screen and reverse-genetics tests to identify several genes involved in lipopolysaccharide production, which, when mutated, restored the ability of the ΔyibD ΔrfbX mutant overexpressing yibD to grow in amylovoran-inducing medium. Remarkably, all the lipopolysaccharide gene mutants tested were defective in lipopolysaccharide and amylovoran production. These results reveal a genetic connection between amylovoran and lipopolysaccharide production in E. amylovora IMPORTANCE This study discovered previously unknown genetic connections between exopolysaccharide and lipopolysaccharide production in the fire blight pathogen Erwinia amylovora This represents a step forward in our understanding of the biology underlying the production of these two macromolecules. Fire blight is an economically important disease that impacts the production of apples and pears worldwide. Few fire blight control measures are available, and growers rely heavily on antibiotic applications at bloom time. Both exopolysaccharide and lipopolysaccharide are E. amylovora virulence factors. Our results indicate that the overexpression of the yibD gene in E. amylovora disrupts both lipopolysaccharide production and exopolysaccharide production. This effect could potentially be used as the basis for the development of an antivirulence treatment for the prevention of fire blight disease.


Assuntos
Proteínas de Bactérias/metabolismo , Erwinia amylovora/genética , Proteínas de Membrana Transportadoras/metabolismo , Doenças das Plantas/microbiologia , Polissacarídeos Bacterianos/biossíntese , Proteínas de Bactérias/genética , Erwinia amylovora/metabolismo , Erwinia amylovora/patogenicidade , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Malus/microbiologia , Proteínas de Membrana Transportadoras/genética , Mutação/genética , Óperon , Pyrus/microbiologia , Virulência/genética
16.
Mol Plant Microbe Interact ; 33(11): 1277-1279, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32808873

RESUMO

Erwinia amylovora causes fire blight, the most devastating bacterial disease of apples and pears in the United States and worldwide. The model strain E. amylovora Ea1189 has been extensively used to understand bacterial pathogenesis and molecular mechanisms of bacterial-plant interactions. In this work, we sequenced and assembled the de novo genome of Ea1189, using a combination of long Oxford Nanopore Technologies and short Illumina sequence reads. A complete gapless genome assembly of Ea1189 consists of a 3,797,741-bp circular chromosome and a 28,259-bp plasmid with 3,472 predicted genes, including 78 transfer RNAs, 22 ribosomal RNAs, and 20 noncoding RNAs. A comparison of the Ea1189 genome to previously sequenced E. amylovora complete genomes showed 99.94 to 99.97% sequence similarity with 314 to 946 single nucleotide polymorphisms. We believe that the availability of the complete genome sequence of strain Ea1189 will further support studies to understand evolution, diversity and structural variations of Erwinia strains, as well as the molecular basis of E. amylovora pathogenesis and its interactions with host plants, thus facilitating the development of effective management strategies for this important disease.


Assuntos
Erwinia amylovora , Genoma Bacteriano , Malus/microbiologia , Doenças das Plantas/microbiologia , Pyrus/microbiologia , Cromossomos Bacterianos , Erwinia amylovora/genética , Plasmídeos
17.
Arch Microbiol ; 202(9): 2391-2400, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32588084

RESUMO

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


Assuntos
Microbiologia de Alimentos , Frutas/microbiologia , Fungos , Metagenômica , Micobioma , Pyrus/microbiologia , Fungos/classificação , Fungos/efeitos dos fármacos , Fungos/genética , Fungicidas Industriais/farmacologia , Micobioma/efeitos dos fármacos , Micobioma/genética
18.
Mol Plant Microbe Interact ; 33(9): 1150-1160, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32432513

RESUMO

Pear ring rot, caused by Botryosphaeria dothidea, is one of the most serious diseases in pear. Calcium (Ca2+) was reported to play a key role in the plant defense response. Here, we found that exogenous calcium could enhance resistance to B. dothidea in pear leaves. Less H2O2 and O2- but more activated reactive oxygen species scavenge enzymes accumulated in calcium-treated leaves than in H2O-treated leaves. Moreover, the increased level of more ascorbic acid-glutathione was maintained by Ca2+ treatment under pathogen infection. The expression of core autophagy-related genes and autophagosome formations were enhanced in Ca2+-treated leaves. Silencing of PbrATG5 in Pyrus betulaefolia conferred sensitivity to inoculation, which was only slightly recovered by Ca2+ treatment. Moreover, the salicylic acid (SA) level and SA-related gene expression were induced more strongly by B. dothidea in Ca2+-treated leaves than in H2O-treated leaves. Taken together, these results demonstrated that exogenous Ca2+ enhanced resistance to B. dothidea by increasing autophagic activity and SA accumulation. Our findings reveal a new mechanism of Ca2+ in increasing the tolerance of pear to B. dothidea infection.


Assuntos
Autofagia , Cálcio/farmacologia , Resistência à Doença , Doenças das Plantas/prevenção & controle , Pyrus/fisiologia , Ácido Salicílico/metabolismo , Proteína 5 Relacionada à Autofagia/genética , Inativação Gênica , Peróxido de Hidrogênio , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Pyrus/microbiologia
19.
Toxins (Basel) ; 12(2)2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-32075318

RESUMO

Black spot caused by Alternaria alternata is one of the important diseases of pear fruit during storage. Isothiocyanates are known as being strong antifungal compounds in vitro against different fungi. The aim of this study was to assess the antifungal effects of the volatile compound 2-phenylethyl isothiocyanate (2-PEITC) against A. alternata in vitro and in pear fruit, and to explore the underlying inhibitory mechanisms. The in vitro results showed that 2-PEITC significantly inhibited spore germination and mycelial growth of A. alternata-the inhibitory effects showed a dose-dependent pattern and the minimum inhibitory concentration (MIC) was 1.22 mM. The development of black spot rot on the pear fruit inoculated with A. alternata was also significantly decreased by 2-PEITC fumigation. At 1.22 mM concentration, the lesion diameter was only 39% of that in the control fruit at 7 days after inoculation. Further results of the leakage of electrolyte, increase of intracellular OD260, and propidium iodide (PI) staining proved that 2-PEITC broke cell membrane permeability of A. alternata. Moreover, 2-PEITC treatment significantly decreased alternariol (AOH), alternariolmonomethyl ether (AME), altenuene (ALT), and tentoxin (TEN) contents of A. alternata. Taken together, these data suggest that the mechanisms underlying the antifungal effect of 2-PEITC against A. alternata might be via reduction in toxin content and breakdown of cell membrane integrity.


Assuntos
Alternaria/efeitos dos fármacos , Antifúngicos/farmacologia , Contaminação de Alimentos/prevenção & controle , Isotiocianatos/farmacologia , Micotoxinas/biossíntese , Pyrus/microbiologia , Alternaria/metabolismo , Alternaria/fisiologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Frutas/microbiologia , Germinação/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Esporos/efeitos dos fármacos , Esporos/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/farmacologia
20.
Curr Microbiol ; 77(5): 875-881, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31938805

RESUMO

A variety of potential inhibitors were tested for the first time for the suppression of Erwinia amylovora, the causal agent of fire blight in apples and pears. Strain variability was evident in susceptibility to inhibitors among five independently isolated virulent strains of E. amylovora. However, most strains were susceptible to culture supernatants from strains of Bacillus spp., and particularly to the recently described species B. nakamurai. Minimal inhibitory concentrations (MICs) were 5-20% (vol/vol) of culture supernatant from B. nakamurai against all five strains of E. amylovora. Although Bacillus species have been previously reported to produce lipopeptide inhibitors of E. amylovora, matrix-assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS) and column chromatography indicated that the inhibitor from B. nakamurai was not a lipopeptide, but rather a novel inhibitor.


Assuntos
Antibiose , Bacillus/fisiologia , Erwinia amylovora/patogenicidade , Doenças das Plantas/prevenção & controle , Bacillus/crescimento & desenvolvimento , Meios de Cultura , Malus/microbiologia , Testes de Sensibilidade Microbiana , Doenças das Plantas/microbiologia , Pyrus/microbiologia
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