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1.
Int J Mol Sci ; 22(11)2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34070394

RESUMO

The genetic control of host response to the fungal necrotrophic disease Septoria nodorum blotch (SNB) in bread wheat is complex, involving many minor genes. Quantitative trait loci (QTL) controlling SNB response were previously identified on chromosomes 1BS and 5BL. The aim of this study, therefore, was to align and compare the genetic map representing QTL interval on 1BS and 5BS with the reference sequence of wheat and identify resistance genes (R-genes) associated with SNB response. Alignment of QTL intervals identified significant genome rearrangements on 1BS between parents of the DH population EGA Blanco, Millewa and the reference sequence of Chinese Spring with subtle rearrangements on 5BL. Nevertheless, annotation of genomic intervals in the reference sequence were able to identify and map 13 and 12 R-genes on 1BS and 5BL, respectively. R-genes discriminated co-located QTL on 1BS into two distinct but linked loci. NRC1a and TFIID mapped in one QTL on 1BS whereas RGA and Snn1 mapped in the linked locus and all were associated with SNB resistance but in one environment only. Similarly, Tsn1 and WK35 were mapped in one QTL on 5BL with NETWORKED 1A and RGA genes mapped in the linked QTL interval. This study provided new insights on possible biochemical, cellular and molecular mechanisms responding to SNB infection in different environments and also addressed limitations of using the reference sequence to identify the full complement of functional R-genes in modern varieties.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Resistência à Doença , Genes de Plantas , Proteínas de Plantas , Ploidias , Triticum , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Triticum/genética , Triticum/microbiologia
2.
Molecules ; 26(6)2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33800987

RESUMO

Phytochemical investigation of the methanolic extract obtained from the aerial parts of Lagochilus setulosus (Lamiaceae) afforded the new compound 1-methoxy-3-O-ß-glucopyranosyl-α-l-oliose (1) together with five known glycosides, namely sitosterol-3-O-ß-glucoside (2), stigmasterol-3-O-ß-glucoside (3), pinitol (4), 6ß-hydroxyl-7-epi-loganin (5), and chlorotuberoside (6). The structures of these compounds were elucidated by extensive spectroscopic analyses, especially HR-MS, 1D and 2D NMR spectroscopy. The in vitro cytotoxic activity of the methanolic extract and the isolated compounds was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and crystal violet (CV) staining assays. In addition, the antifungal activities of the components were evaluated against Botrytis cinerea, Septoria tritici, and Phytophthora infestans. The anthelmintic potential was determined against Caenorhabditis elegans nematodes. Neither the extract nor the isolated compounds showed promising activity in all the bioassays.


Assuntos
Anti-Helmínticos , Antifúngicos , Glicosídeos , Lamiaceae/química , Extratos Vegetais/química , Animais , Anti-Helmínticos/química , Anti-Helmínticos/isolamento & purificação , Anti-Helmínticos/farmacologia , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Ascomicetos/crescimento & desenvolvimento , Botrytis/crescimento & desenvolvimento , Caenorhabditis elegans/crescimento & desenvolvimento , Glicosídeos/química , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Phytophthora infestans/crescimento & desenvolvimento
3.
Int J Mol Sci ; 22(4)2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33670294

RESUMO

Verticillium wilt is threatening the world's cotton production. The pathogenic fungus Verticillium dahliae can survive in the soil in the form of microsclerotia for a long time, colonize through the root of cotton, and invade into vascular bundles, causing yellowing and wilting of cotton leaves, and in serious cases, leading to plant death. Breeding resistant varieties is the most economical and effective method to control Verticillium wilt. In previous studies, proteomic analysis was carried out on different cotton varieties inoculated with V. dahliae strain Vd080. It was found that GhRPS6 was phosphorylated after inoculation, and the phosphorylation level in resistant cultivars was 1.5 times than that in susceptible cultivars. In this study, knockdown of GhRPS6 expression results in the reduction of SA and JA content, and suppresses a series of defensive response, enhancing cotton plants susceptibility to V. dahliae. Overexpression in Arabidopsis thaliana transgenic plants was found to be more resistant to V. dahliae. Further, serines at 237 and 240 were mutated to phenylalanine, respectively and jointly. The transgenic Arabidopsis plants demonstrated that seri-237 compromised the plant resistance to V. dahliae. Subcellular localization in Nicotiana benthamiana showed that GhRPS6 was localized in the nucleus. Additionally, the pathogen inoculation and phosphorylation site mutation did not change its localization. These results indicate that GhRPS6 is a potential molecular target for improving resistance to Verticillium wilt in cotton. This lays a foundation for breeding disease-resistant varieties.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Gossypium , Doenças das Plantas , Proteínas de Plantas , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Estudo de Associação Genômica Ampla , Gossypium/genética , Gossypium/metabolismo , Gossypium/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/microbiologia
4.
Int J Mol Sci ; 22(4)2021 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-33668507

RESUMO

Botrytis squamosa, Botrytis aclada, and Sclerotium cepivorum are three fungal species of the family Sclerotiniaceae that are pathogenic on onion. Despite their close relatedness, these fungi cause very distinct diseases, respectively called leaf blight, neck rot, and white rot, which pose serious threats to onion cultivation. The infection biology of neck rot and white rot in particular is poorly understood. In this study, we used GFP-expressing transformants of all three fungi to visualize the early phases of infection. B. squamosa entered onion leaves by growing either through stomata or into anticlinal walls of onion epidermal cells. B. aclada, known to cause post-harvest rot and spoilage of onion bulbs, did not penetrate the leaf surface but instead formed superficial colonies which produced new conidia. S. cepivorum entered onion roots via infection cushions and appressorium-like structures. In the non-host tomato, S. cepivorum also produced appressorium-like structures and infection cushions, but upon prolonged contact with the non-host the infection structures died. With this study, we have gained understanding in the infection biology and strategy of each of these onion pathogens. Moreover, by comparing the infection mechanisms we were able to increase insight into how these closely related fungi can cause such different diseases.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Botrytis/crescimento & desenvolvimento , Cebolas/microbiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia
5.
Appl Environ Microbiol ; 87(10)2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33637575

RESUMO

A group of polyene macrolides mainly composed of two constituents was isolated from the fermentation broth of Streptomyces roseoflavus Men-myco-93-63, which was isolated from soil where potato scabs were repressed naturally. One of these macrolides was roflamycoin, which was first reported in 1968, and the other was a novel compound named Men-myco-A, which had one methylene unit more than roflamycoin. Together, they were designated RM. This group of antibiotics exhibited broad-spectrum antifungal activities in vitro against 17 plant-pathogenic fungi, with 50% effective concentrations (EC50) of 2.05 to 7.09 µg/ml and 90% effective concentrations (EC90) of 4.32 to 54.45 µg/ml, which indicates their potential use in plant disease control. Furthermore, their biosynthetic gene cluster was identified, and the associated biosynthetic assembly line was proposed based on a module and domain analysis of polyketide synthases (PKSs), supported by findings from gene inactivation experiments.IMPORTANCE Streptomyces roseoflavus Men-myco-93-63 is a biocontrol strain that has been studied in our laboratory for many years and exhibits a good inhibitory effect in many crop diseases. Therefore, the identification of antimicrobial metabolites is necessary and our main objective. In this work, chemical, bioinformatic, and molecular biological methods were combined to identify the structures and biosynthesis of the active metabolites. This work provides a new alternative agent for the biological control of plant diseases and is helpful for improving both the properties and yield of the antibiotics via genetic engineering.


Assuntos
Agentes de Controle Biológico , Macrolídeos/metabolismo , Polienos/metabolismo , Streptomyces/metabolismo , Ascomicetos/efeitos dos fármacos , Ascomicetos/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Vias Biossintéticas/genética , Macrolídeos/farmacologia , Família Multigênica , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Doenças das Plantas/prevenção & controle , Polienos/farmacologia , Streptomyces/genética
6.
J Agric Food Chem ; 69(4): 1430-1440, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33481591

RESUMO

Sclerotinia sclerotiorum is a ubiquitous necrotrophic pathogenic fungus causing significant losses in a broad range of plant species. Sclerotia formed by S. sclerotiorum play important roles in both the fungal life cycle and the disease development cycle. Sclerotial exudation during sclerotial development is a characteristic feature of this fungus. In this study, a proteome-level investigation of proteins present in sclerotial exudates was conducted by high-throughput LC-MS/MS analysis. A total of 258 proteins were identified, in which 193 were annotated by GO annotation and 54 were classified by KEGG analysis. Four proteins related to plant cell wall degradation were further validated by measuring the corresponding enzymatic activity of the sclerotial exudates and/or by assessing the gene expression during sclerotial development. Results indicated that the proteins identified in sclerotial exudates help in the development of sclerotia and contribute to host cell necrosis caused by S. sclerotiorum. Furthermore, we proposed that sclerotial exudates can degrade plant cell walls to release carbohydrates that provide nutrition for fungal growth and possibly facilitate fungal cell wall assembly in developing sclerotia. This study also provides new insights on the morphogenesis and pathogenicity of other sclerotia-forming fungi.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Parede Celular/genética , Proteínas Fúngicas/metabolismo , Ascomicetos/química , Ascomicetos/genética , Parede Celular/metabolismo , Cromatografia Líquida , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteômica , Espectrometria de Massas em Tandem
7.
J Agric Food Chem ; 69(4): 1259-1271, 2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33496176

RESUMO

Inspired by the widely antiphytopathogenic application of diversified derivatives from natural sources, cryptolepine and its derivatives were subsequently designed, synthesized, and evaluated for their antifungal activities against four agriculturally important fungi Rhizoctonia solani, Botrytis cinerea, Fusarium graminearum, and Sclerotinia sclerotiorum. The results obtained from in vitro assay indicated that compounds a1-a24 showed great fungicidal property against B. cinerea (EC50 < 4 µg/mL); especially, a3 presented significantly prominent inhibitory activity with an EC50 of 0.027 µg/mL. In the pursuit of further expanding the antifungal spectrum of cryptolepine, ring-opened compound f1 produced better activity with an EC50 of 3.632 µg/mL against R. solani and an EC50 of 5.599 µg/mL against F. graminearum. Furthermore, a3 was selected to be a candidate to investigate its preliminary antifungal mechanism to B. cinerea, revealing that not only spore germination was effectively inhibited and the normal physiological structure of mycelium was severely undermined but also detrimental reactive oxygen was obviously accumulated and the normal function of the nucleus was fairly disordered. Besides, in vivo curative experiment against B. cinerea found that the therapeutic action of a3 was comparable to that of the positive control azoxystrobin. These results suggested that compound a3 could be regarded as a novel and promising agent against B. cinerea for its valuable potency.


Assuntos
Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Alcaloides Indólicos/química , Alcaloides Indólicos/farmacologia , Quinolinas/química , Quinolinas/farmacologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/crescimento & desenvolvimento , Desenho de Fármacos , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimento , Relação Estrutura-Atividade
8.
J Agric Food Chem ; 69(3): 974-981, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33443412

RESUMO

Natural phenazines are a class of multifunctional secondary metabolites of bacteria that play an important role in the biocontrol of plant pathogens. In this paper, a novel bioactive phenazine derivative was isolated from Streptomyces lomondensis S015 through silica gel chromatography and preparative high-performance liquid chromatography (HPLC). The structure was identified as 1-carboxyl-6-formyl-4,7,9-trihydroxy-phenazine (CFTHP) by NMR spectroscopy in combination with ultraperformance liquid chromatography & mass spectrometry (UPLC-MS). CFTHP could inhibit Pythium ultimum, Rhizoctonia solani, Septoria steviae, and Fusarium oxysporum f. sp. niveum with minimal inhibitory concentration (MIC) values of 16, 32, 16, and 16 µg/mL, respectively. A global regulatory gene phoP could positively regulate CFTHP biosynthesis since its production was 3.0-fold enhanced by phoP overexpression and inhibited by phoP deletion in Streptomyces lomondensis S015. These studies illustrated the potential of CFTHP as a promising biopesticide and provided a reference for phenazine production improvement.


Assuntos
Proteínas de Bactérias/metabolismo , Agentes de Controle Biológico/química , Agentes de Controle Biológico/farmacologia , Fungicidas Industriais/química , Fenazinas/química , Fenazinas/farmacologia , Streptomyces/metabolismo , Ascomicetos/efeitos dos fármacos , Ascomicetos/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Agentes de Controle Biológico/metabolismo , Cromatografia Líquida de Alta Pressão , Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Fenazinas/metabolismo , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimento , Metabolismo Secundário , Streptomyces/química , Streptomyces/genética
9.
World J Microbiol Biotechnol ; 37(1): 14, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33394165

RESUMO

Chickpea (Cicer arietinum L., Fabaceae) is the second most important legume after common bean (Phaseolus vulgaris L., Fabaceae) and third in production among the legumes grains worldwide. Ascochyta blight and Fusarium wilt are among the main fungal infections which cause the major losses of chickpea crop. In this work we report the phyto-pathogen controlling properties of 24 endophyte Phomopsis/Diaporthe isolates on the chickpea fungal pathogens Ascochyta rabiei, Fusarium oxysporum and Fusarium solani. The Phomopsis/Diaporthe strains were isolated amongst a total of 62 endophytic fungi from the aerial parts of the herbaceous perennial American plant Peperomia obtusifolia (Piperaceae) along with Fusarium, Septoria, Colletotrichum, Alternaria and Roussoella genera among others. Phomopsis/Diaporthe isolates were identified as Diaporthe infecunda (12 isolates), Diaporthe sackstoni (1 isolate), Diaporthe cf. brasiliensis (4 isolates) and Phomopsis cf. tuberivora (7 isolates). All the Phomopsis/Diaporthe strains antagonized A. rabiei strain AR2 with a mean of inhibition (% I) of 86.59 ± 1.49% in dual cultures. The metabolic characterization of the Phomopsis/Diaporthe strains showed groups in three clusters which were in agreement with the taxonomic identification. Bioautographic evaluation of organic extracts showed that those of D. cf. brasiliensis and D. infecunda were better as inhibitors. Strain Po 45 was one of the most active (cluster 1, 96.87% I), and its ethyl acetate extract inhibited A. rabiei growth in a bioautographic assay until at least 10 µg/mm applied showing a specific chromatographic band as the responsible of the A. rabiei inhibition.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Cicer/crescimento & desenvolvimento , Endófitos/fisiologia , Peperomia/microbiologia , Doenças das Plantas/prevenção & controle , Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Ascomicetos/patogenicidade , Ascomicetos/fisiologia , Cicer/microbiologia , Técnicas de Cocultura , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Endófitos/classificação , Endófitos/isolamento & purificação , Viabilidade Microbiana , Filogenia , Componentes Aéreos da Planta/microbiologia , Doenças das Plantas/microbiologia
10.
Exp Parasitol ; 218: 108005, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32971132

RESUMO

Nematodiosis are responsible for financial losses in cattle production systems due to treatment costs, falling production rates and animal deaths. The incorporation of sodium alginate pellets containing nematophagous fungi in the bovine diet is a method for the control of nematodiosis. The aims of this study were to evaluate the viability of Arthrobotrys cladodes and Pochonia chlamydosporia contained in sodium alginate pellets after passage through the bovine gastrointestinal tract, as well as to evaluate the effects of single and combined use of these fungi against bovine parasitic nematodes. The reduction in parasitic nematode infective larvae of bovines by the combined use of Arthrobotrys cladodes and Pochonia chlamydosporia was more than the reduction in infective larvae by Arthrobotrys cladodes or Pochonia chlamydosporia alone in the collections 12, 24 and 36 h after giving the pellets to the animals. Arthrobotrys cladodes and Pochonia chlamydosporia combined promoted maximum reduction of infective larvae of 86.3%. Therefore, the combination of Arthrobotrys cladodes and Pochonia chlamydosporia may be an effective method to control gastrointestinal nematodiosis affecting grazing cattle.


Assuntos
Ascomicetos/fisiologia , Doenças dos Bovinos/prevenção & controle , Trato Gastrointestinal/microbiologia , Hypocreales/fisiologia , Infecções por Nematoides/veterinária , Análise de Variância , Animais , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico , Bovinos , Doenças dos Bovinos/parasitologia , Fezes/parasitologia , Feminino , Trato Gastrointestinal/parasitologia , Hypocreales/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Micélio/crescimento & desenvolvimento , Nematoides/crescimento & desenvolvimento , Nematoides/microbiologia , Infecções por Nematoides/prevenção & controle
11.
PLoS One ; 15(9): e0239001, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915896

RESUMO

White-nose syndrome is a fungal disease responsible for the rapid decline of North American bat populations. This study addressed a novel method for inactivating Pseudogymnoascus destructans, the causative agent of WNS, using ultraviolet A (UVA) or B (UVB) radiation in combination with methoxsalen, a photosensitizer from the furanocoumarin family of compounds. Fungal spore suspensions were diluted in micromolar concentrations of methoxsalen (50-500 µM), then exposed to fixed doses of UVA radiation (500-5000 mJ/cm2), followed by plating on germination media. These plates were examined for two to four weeks for evidence of spore germination or inactivation, along with resultant growth or inhibition of P. destructans colonies. Pretreatment of fungal spores with low doses of methoxsalen resulted in a UVA dose-dependent inactivation of the P. destructans spores. All doses of methoxsalen paired with 500 mJ/cm2 of UVA led to an approximate two-log10 (~99%) reduction in spore viability, and when paired with 1000 mJ/cm2, a four-log10 or greater (>99.99%) reduction in spore viability was observed. Additionally, actively growing P. destructans colonies treated directly with methoxsalen and either UVA or UVB radiation demonstrated UV dose-dependent inhibition and termination of colony growth. This novel approach of using a photosensitizer in combination with UV radiation to control fungal growth may have broad, practical application in the future.


Assuntos
Ascomicetos/efeitos da radiação , Quirópteros/microbiologia , Metoxaleno/administração & dosagem , Micoses/veterinária , Fármacos Fotossensibilizantes/administração & dosagem , Terapia Ultravioleta , Animais , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Micoses/radioterapia , Esporos Fúngicos/patogenicidade , Esporos Fúngicos/efeitos da radiação , Síndrome
12.
PLoS One ; 15(8): e0236822, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764772

RESUMO

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


Assuntos
Ascomicetos/crescimento & desenvolvimento , Penicillium/crescimento & desenvolvimento , Água do Mar/microbiologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/isolamento & purificação , Meios de Cultura/química , Meios de Cultura/farmacologia , Glucose/farmacologia , Glicerol/farmacologia , Penicillium/efeitos dos fármacos , Penicillium/isolamento & purificação , Xilose/farmacologia
13.
Nat Commun ; 11(1): 3897, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753587

RESUMO

Lipo-chitooligosaccharides (LCOs) are signaling molecules produced by rhizobial bacteria that trigger the nodulation process in legumes, and by some fungi that also establish symbiotic relationships with plants, notably the arbuscular and ecto mycorrhizal fungi. Here, we show that many other fungi also produce LCOs. We tested 59 species representing most fungal phyla, and found that 53 species produce LCOs that can be detected by functional assays and/or by mass spectroscopy. LCO treatment affects spore germination, branching of hyphae, pseudohyphal growth, and transcription in non-symbiotic fungi from the Ascomycete and Basidiomycete phyla. Our findings suggest that LCO production is common among fungi, and LCOs may function as signals regulating fungal growth and development.


Assuntos
Quitina/análogos & derivados , Quitina/metabolismo , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Transdução de Sinais/fisiologia , Ascomicetos/crescimento & desenvolvimento , Basidiomycota/crescimento & desenvolvimento , Ecologia , Ácidos Graxos/metabolismo , Micorrizas/fisiologia , Rhizobium/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Simbiose/fisiologia
14.
Int J Food Microbiol ; 333: 108788, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-32711131

RESUMO

The microbial variability on the host plant surface must be maintained because population diversity and quantity are essential to avoid disease development. It would be necessary to examine the patterns and mechanisms associated with the massive and reiterative introduction of a microbial pest control agent. The effect of inundative releases of biopesticide formulations containing Penicillium frequentans for the control of Monilinia spp. populations, and the effect on fruit surface microbiota on 18 stone fruit field experiments located in four European countries for more than two crop seasons against brown rot were studied. P. frequentans was monitored after application in order to assess whether it was persistent or not in the environment. Hydrolysis of fluorescein diacetate and denaturing gradient gel electrophoresis were used to study the effects of P. frequentans on fungal and bacterial non-target populations on fruit surface. The effect of P. frequentans formulations on the populations of Monilinia spp. on fruit was also assessed in different orchards. P. frequentans population on stone fruit surfaces showed ranged from 100 to 10,000 CFU cm-2, and postharvest recovered populations were more than 10-100-fold higher than preharvest recovered populations. The population of P. frequentans varied among orchards and years, rather than by the type of formulation. P. frequentans formulation reduced Monilinia spp. population and brown rot and latent infections caused by this pathogen both before and at harvest, while stabilizing or increasing antagonist populations and avoiding non-target microorganisms. However, fungicides reduced significantly the microbial activity on nectarine surfaces.


Assuntos
Antibiose/fisiologia , Ascomicetos/crescimento & desenvolvimento , Agentes de Controle Biológico/farmacologia , Fungicidas Industriais/farmacologia , Penicillium/metabolismo , Europa (Continente) , Frutas/microbiologia , Microbiota , Doenças das Plantas/microbiologia
15.
PLoS One ; 15(7): e0236429, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730288

RESUMO

The soilborne fungus Gaeumannomyces tritici (G. tritici) causes the take-all disease on wheat roots. Ambient pH has been shown to be critical in different steps of G. tritici life cycle such as survival in bulk soil, saprophytic growth, and pathogenicity on plants. There are however intra-specific variations and we previously found two types of G. tritici strains that grow preferentially either at acidic pH or at neutral/alkaline pH; gene expression involved in pH-signal transduction pathway and pathogenesis was differentially regulated in two strains representative of these types. To go deeper in the description of the genetic pathways and the understanding of this adaptative mechanism, transcriptome sequencing was achieved on two strains (PG6 and PG38) which displayed opposite growth profiles in two pH conditions (acidic and neutral). PG6, growing better at acidic pH, overexpressed in this condition genes related to cell proliferation. In contrast, PG38, which grew better at neutral pH, overexpressed in this condition genes involved in fatty acids and amino acid metabolisms, and genes potentially related to pathogenesis. This strain also expressed stress resistance mechanisms at both pH, to assert a convenient growth under various ambient pH conditions. These differences in metabolic pathway expression between strains at different pH might buffer the effect of field or soil variation in wheat fields, and explain the success of the pathogen.


Assuntos
Ascomicetos/genética , Transcriptoma/genética , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/isolamento & purificação , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica , Ontologia Genética , Genes Fúngicos , Concentração de Íons de Hidrogênio , Micélio/crescimento & desenvolvimento , Especificidade da Espécie , Triticum
16.
Biofouling ; 36(3): 308-318, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32401558

RESUMO

In the present study, the composition of the extracellular matrix (ECM) of the biofilm formed by Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans on a polystyrene surface was investigated. Confocal laser scanning microscopy revealed a dense mycelial mass, with an ECM covering/interspersing the fungal cells and containing carbohydrate-rich molecules (e.g. glycoproteins) and extracellular DNA. The ECMs that were chemically extracted from mature biofilms formed by each of these fungi was predominantly composed of polysaccharides, followed by proteins, nucleic acids and sterols. In general, the amount of biofilm ECM was significantly greater in S. minutisporum and S. aurantiacum than in S. apiospermum and L. prolificans. Corroborating these results, the disarticulation of mature biofilms with enzymes, sodium metaperiodate and chelating agents occurred mainly in S. minutisporum and S. aurantiacum. Collectively, these results have revealed for the first time the composition of the ECM of the biofilms formed by Scedosporium/Lomentospora species and the role it plays in their architecture.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Biofilmes/crescimento & desenvolvimento , Matriz Extracelular/metabolismo , Scedosporium/crescimento & desenvolvimento , Ascomicetos/metabolismo , Humanos , Microscopia Confocal , Poliestirenos/química , Scedosporium/metabolismo , Propriedades de Superfície
17.
J Appl Microbiol ; 129(5): 1364-1373, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32455497

RESUMO

AIM: To investigate the antifungal effect of the neem extract volatile propyl disulphide against the fungal plant pathogens. METHODS AND RESULTS: Postharvest pathogens were isolated and identified as Lasiodiplodia theobromae and Neofusicoccum parvum causing the stem end rot of mango fruit. Antifungal activity of propyl disulphide at different concentrations was determined in comparison with ethanol and distilled water. Both diffusion assays were effective in controlling the mycelial growth of the tested fungi. The high coefficient of determination (R2 , 0·970-0·997) of the growth curves indicated the good fit of the experimental data to the Gompertz growth model. Propyl disulphide significantly (P ≤ 0·05) decreased the mycelial growth during the stationary phase (A) and increased the lag phase (λ) than both control (ethanol and distilled water). CONCLUSION: This compound can potentially be applied to other tropical and subtropical fruits for the successful control of postharvest losses of fresh produce. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of propyl disulphide from neem extract against plant pathogens and could be beneficial for effective microbial decay prevention in food industries.


Assuntos
Ascomicetos/efeitos dos fármacos , Azadirachta/química , Dissulfetos/farmacologia , Fungicidas Industriais/farmacologia , Mangifera/microbiologia , Doenças das Plantas/microbiologia , Ascomicetos/crescimento & desenvolvimento , Microbiologia de Alimentos , Frutas/microbiologia , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Extratos Vegetais/química , Extratos Vegetais/farmacologia
18.
PLoS One ; 15(4): e0231453, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298310

RESUMO

A laccase-producing ascomycete fungus was isolated from soil collected around the premises of a textile dye factory and identified as Nectriella pironii. Efficient laccase production was achieved via the synergistic action of 1 mM copper sulfate and ferulic acid. Extracts of rapeseed oil cake, grass hay, and leaf litter collected in a pocket urban park were used for enzyme production. The highest laccase activity (3,330 U/L) was observed in the culture grown on the leaf litter extract. This is the first report on biosynthesis of laccase by N. pironii. This is also the first study on utilization of naturally fallen park leaves as a substrate for fungal laccase production. The extracellular enzyme possessing laccase activity was purified to homogeneity by ion-exchange and gel filtration chromatographic techniques. The amino acid sequence of the protein revealed highest similarity to the laccase enzyme produced by Stachybotrys chartarum-and considerable homology to those produced by other fungal species. The purified laccase possessed a molecular mass of 50 kDa. The enzyme had an optimum pH of 2.0 or 6.0 and retained more than 50% of residual activity after 3 hours of incubation at pH 3.0-10.6 or 4.0-9.0 when 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid or 2,6-dimethoxyphenol, respectively, were used. Dithiothreitol, ß-mercaptoethanol, and sodium azide at 1 mM concentration strongly inhibited the laccase activity, while in the presence of 50 mM urea, the enzyme was found to retain 25% of its activity. The laccase was able to decolorize more than 80% of Indigo Carmine, Remazol Brilliant Blue R, Reactive Orange 16, and Acid Red 27 dyes within 1 h. The possibility of leaf litter use for the production of the laccase enzyme from N. pironii (IM 6443), exhibiting high pH stability and degradative potential, makes it a promising tool for use in different environmental and industrial operations.


Assuntos
Ascomicetos/enzimologia , Lacase/metabolismo , Parques Recreativos , Folhas de Planta/microbiologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Microbiologia do Solo
19.
Zhongguo Zhong Yao Za Zhi ; 45(1): 65-71, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-32237412

RESUMO

The interaction of endophytes and host plant is an effective mean to regulate the growth and secondary metabolism of medicinal plants. Here we want to elucidate the effects and mechanism of Phoma herbarum D603 on the root development and tanshinone synthesis in root of Salvia miltiorrhiza by endophyte-plant coculture system. The mycelium of P. herbarum D603 was colonized in the root tissue space, and formed a stable symbiotic relationship with host plant. The in vitro activities analysis showed that the concentration of IAA produced by D603 can reach(6.45±0.23) µg·mL~(-1), and this strain had some abilities of phosphorus solubilization and siderophore production activities. The coculture experiment showed that strain D603 can significantly promote the synthesis and accumulation of tanshinones in the root of S. miltiorrhiza, in which after 8 weeks of treatment with D603, the content of tanshinone Ⅱ_A in the roots reached up to(1.42±0.59) mg·g~(-1). By the qRT-PCR analysis results, we found that D603 could improve the expression levels of some key genes(DXR, DXS, GGPP, HMGR, CPS) of tanshinone biosynthesis pathway in host plant S. miltiorrhiza, but the promoting effect mainly occurred in the early stage of the interaction, and the enzyme activity level decreased in varying degrees of the later stage. In summary, seed-associated endophyte P. herbarum D603 can promote the growth and root development of S. miltiorrhiza by producing hormones, promoting nutrient absorption and siderophore production, and promote the synthesis and accumulation of tanshinones by regulating the expression level of key genes in the synthetic pathway in S. miltiorrhiza.


Assuntos
Abietanos/biossíntese , Ascomicetos/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Salvia miltiorrhiza/microbiologia , Endófitos/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Salvia miltiorrhiza/metabolismo , Sementes/microbiologia
20.
Lett Appl Microbiol ; 71(2): 154-163, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32255198

RESUMO

Cowpea is an important pulse crop cultivated in arid and semi-arid regions of the world. During field survey, a characteristic wilt was observed in around 45 ha of cowpea fields with incidence 17-25%. Infection was seen in pre-flowering stage and infected plants showed quick wilt symptoms with tan lesions near the stem-soil interface. Fungal pathogens associated were isolated on PDA, which produced dark to grey olivaceous colonies in the centre, and aerial mycelia were appressed with floccose and white to smoke-grey. Conidia are aseptate, initially hyaline, smooth-walled, broadly ellipsoidal with rounded ends becoming dark brown. Based on these morphological features, the fungal pathogen was identified as Aplosporella sp. The ITS-rDNA region was amplified using ITS1/ITS4 primers and sequenced. The nBLAST and phylogenetic analysis confirmed the pathogen as Aplosporella hesperidica. The Koch's postulates were performed on 45-days-old cowpea plants with mycelial disc of A. hesperidica. Development of typical necrotic lesions was observed after 28 days of post-inoculation and the pathogen's identity was confirmed based on re-isolation. Efficacy of fungicides evaluated in vitro showed that the pathogen is highly sensitive to systemic fungicides rather than the contact fungicides. The cowpea production was severely affected owing to the causative agent A. hesperidica. The collar rot disease of cowpea by A. hesperidica is the first report in India. SIGNIFICANCE AND IMPACT OF THE STUDY: A new collar rot disease of cowpea recorded from India has been investigated. The necrotic lesions were enlarged and eventually quick wilt and death of the host plant was observed with incidence ranged from 17 to 25%. Associated fungal pathogen was isolated and identified as Aplosporella hesperidica based on morphology and ITS-rDNA sequence analysis. Koch's postulates were performed under greenhouse conditions and in vitro evaluation of fungicides shows that the pathogen is sensitive to systemic fungicides. This is the first report of A. hesperidica causing collar rot disease of cowpea in India.


Assuntos
Ascomicetos/efeitos dos fármacos , Ascomicetos/genética , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Vigna/microbiologia , Ascomicetos/classificação , Ascomicetos/crescimento & desenvolvimento , DNA Ribossômico/genética , Índia , Testes de Sensibilidade Microbiana , Micélio/fisiologia , Filogenia , Esporos Fúngicos/fisiologia
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