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1.
An Acad Bras Cienc ; 91(3): e20181295, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432907

RESUMO

The banana tree is associated with different species of endophytic bacteria that can stimulate plant growth. However, further studies are needed to better understand the relationships between this group of bacteria and the host plant. The objective of this study was to investigate the localization of the EB-40 (Bacillus sp.) through anatomical and ultrastructural analyses in micropropagated banana plantlets. The results demonstrated the effective colonization of the EB-40 isolate in the intercellular and intracellular spaces, as well as in the rhizosphere region. The wall of endophytic bacteria contains calcium and nitrogen. The EB-40 isolate was also observed to associate with the plasma membrane and cell wall. These results further our understanding of the mechanisms involved in the colonization of plant cells by endophytic bacteria in micropropagated banana plantlets.


Assuntos
Bacillus/fisiologia , Endófitos/ultraestrutura , Musa/microbiologia , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Bacillus/ultraestrutura , Microscopia Eletrônica de Varredura , Musa/crescimento & desenvolvimento , Musa/ultraestrutura , Raízes de Plantas/crescimento & desenvolvimento
2.
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
3.
World J Microbiol Biotechnol ; 35(7): 105, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267317

RESUMO

Pseudocercospora fijiensis causes black Sigatoka disease, the most important threat to banana. The cell wall is crucial for fungal biological processes, including pathogenesis. Here, we performed cell wall proteomics analyses of two P. fijiensis strains, the highly virulent Oz2b, and the less virulent C1233 strains. Strains were starved from nitrogen to mimic the host environment. Interestingly, in vitro cultures of the C1233 strain grew faster than Oz2b in PDB medium, suggesting that C1233 survives outside the host better than the highly virulent Oz2b strain. Both strains were submitted to nitrogen starvation and the cell wall proteins were isolated and subjected to nano-HPLC-MS/MS. A total of 2686 proteins were obtained from which only 240 had a known function and thus, bioinformatics analyses were performed on this group. We found that 90 cell wall proteins were shared by both strains, 21 were unique for Oz2b and 39 for C1233. Shared proteins comprised 24 pathogenicity factors, including Avr4 and Ecp6, two effectors from P. fijiensis, while the unique proteins comprised 16 virulence factors in C1233 and 11 in Oz2b. The P. fijiensis cell wall proteome comprised canonical proteins, but thirty percent were atypical, a feature which in other phytopathogens has been interpreted as contamination. However, a comparison with the identities of atypical proteins in other reports suggests that the P. fijiensis proteins we detected were not contaminants. This is the first proteomics analysis of the P. fijiensis cell wall and our results expands the understanding of the fundamental biology of fungal phytopathogens and will help to decipher the molecular mechanisms of pathogenesis and virulence in P. fijiensis.


Assuntos
Ascomicetos/genética , Ascomicetos/metabolismo , Parede Celular/genética , Parede Celular/metabolismo , Proteoma , Fatores de Virulência/genética , Fatores de Virulência/metabolismo , Ascomicetos/isolamento & purificação , Ascomicetos/patogenicidade , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genes Fúngicos/genética , Genoma Fúngico , Musa/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Espectrometria de Massas em Tandem , Virulência
4.
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
5.
Plant Physiol Biochem ; 141: 83-94, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31136934

RESUMO

Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc), is one of the most devastating diseases in bananas resulting in significant loss of Cavendish bananas production worldwide. Here we show the agronomic traits and the resistance of 'Guijiao 9' in the field trials from 2012 to 2017. And then we dissect and compare the transcriptome response from these two cultivars (cv. 'Guijiao 9' and cv. Williams) in an attempt to understand the molecular basis that contribute to the enhanced Foc tropical race 4 (Foc-TR4) resistance. 'Guijiao 9' is a Cavendish cultivar with strong resistance to Foc-TR4, which was reflected in a lower disease severity and incidence in glasshouse and field trails, when compared to the susceptible cultivar Williams. Gene expression profiles of 'Guijiao 9' and Williams were captured by performing RNA-Seq analysis on 16 biological samples collected over a six day period post inoculation with Foc-TR4. Transcriptional reprogramming in response to Foc-TR4 was detected in both genotypes but the response was more drastic in 'Guijiao 9' than in Williams. Specific genes involved in plant-pathogen interaction and defense signaling including MAPK, calcium, salicylic acid, jasmonic acid and ethylene pathways were analyzed and compared between 'Guijiao 9' and Williams. Genes associated with defense-related metabolites synthesis such as NB-LRR proteins, calmodulin-binding protein and phenylpropanoids biosynthesis genes were significantly up-regulated in 'Guijiao 9' resistant to Foc-TR4 infection. Taken together, this study highlights the important roles of plant hormone regulation and defense gene activation in mediating resistance in 'Guijiao 9'.


Assuntos
Resistência à Doença/genética , Fusarium/patogenicidade , Regulação da Expressão Gênica de Plantas , Musa/genética , Doenças das Plantas/genética , DNA Complementar/genética , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Biblioteca Gênica , Genes de Plantas , Musa/microbiologia , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/genética , Ácido Salicílico/metabolismo , Metabolismo Secundário , Especificidade da Espécie , Transcrição Genética , Transcriptoma , Regulação para Cima
6.
BMC Genomics ; 20(1): 378, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088352

RESUMO

BACKGROUND: Banana is one of the most important crops in tropical and sub-tropical regions. To meet the demands of international markets, banana plantations require high amounts of chemical fertilizers which translate into high farming costs and are hazardous to the environment when used excessively. Beneficial free-living soil bacteria that colonize the rhizosphere are known as plant growth-promoting rhizobacteria (PGPR). PGPR affect plant growth in direct or indirect ways and hold great promise for sustainable agriculture. RESULTS: PGPR of the genera Bacillus and Pseudomonas in banana cv. Williams were evaluated. These plants were produced through in vitro culture and inoculated individually with two rhizobacteria, Bacillus amyloliquefaciens strain Bs006 and Pseudomonas fluorescens strain Ps006. Control plants without microbial inoculum were also evaluated. These plants were kept in a controlled climate growth room with conditions required to favor plant-microorganism interactions. These interactions were evaluated at 1-, 48- and 96-h using transcriptome sequencing after inoculation to establish differentially expressed genes (DEGs) in plants elicited by the interaction with the two rhizobacteria. Additionally, droplet digital PCR was performed at 1, 48, 96 h, and also at 15 and 30 days to validate the expression patterns of selected DEGs. The banana cv. Williams transcriptome reported differential expression in a large number of genes of which 22 were experimentally validated. Genes validated experimentally correspond to growth promotion and regulation of specific functions (flowering, photosynthesis, glucose catabolism and root growth) as well as plant defense genes. This study focused on the analysis of 18 genes involved in growth promotion, defense and response to biotic or abiotic stress. CONCLUSIONS: Differences in banana gene expression profiles in response to the rhizobacteria evaluated here (Bacillus amyloliquefaciens Bs006 and Pseudomonas fluorescens Ps006) are influenced by separate bacterial colonization processes and levels that stimulate distinct groups of genes at various points in time.


Assuntos
Bacillus amyloliquefaciens/fisiologia , Perfilação da Expressão Gênica/métodos , Musa/crescimento & desenvolvimento , Proteínas de Plantas/genética , Pseudomonas fluorescens/fisiologia , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Musa/genética , Musa/microbiologia , Análise de Sequência de RNA , Microbiologia do Solo , Estresse Fisiológico
7.
J Appl Microbiol ; 127(2): 544-555, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31077517

RESUMO

AIMS: This study sought to investigate the effect of bioformulation on the biocontrol efficacy, microbial viability and storage stability of a consortium of Pseudomonas aeruginosa DRB1 and Trichoderma harzianum CBF2 against Foc Tropical Race 4 (Foc-TR4). MATERIALS AND RESULTS: Four bioformulations consisting of dry (pesta granules, talc powder and alginate beads) and liquid formulations were evaluated for their ability to control Foc-TR4, sustain microbial populations after application and maintain microbial stability during storage. All tested bioformulations reduced disease severity (DS) by more than 43·00% with pesta granules producing the highest reduction in DS by 66·67% and the lowest area under the disease progress curve value (468·75) in a glasshouse trial. Microbial populations of DRB1 and CBF2 were abundant in the rhizosphere, rhizoplane and within the roots of bananas after pesta granules application as compared to talc powder, alginate beads and liquid formulations 84 days after inoculation (DAI). The stability of both microbial populations after 180 days of storage at 4°C was the greatest in the pesta granule formulation. CONCLUSION: The pesta granule formulation was a suitable carrier of biological control agents (BCA) without compromising biocontrol efficacy, microbial population and storage stability as compared to other bioformulations used in this study. SIGNIFICANCE AND IMPACT OF THE STUDY: Pesta granules could be utilized to formulate BCA consortia into biofertilizers. This formulation could be further investigated for possible applications under agricultural field settings.


Assuntos
Agentes de Controle Biológico , Fusarium , Musa/microbiologia , Doenças das Plantas/prevenção & controle , Pseudomonas aeruginosa , Trichoderma , Consórcios Microbianos , Viabilidade Microbiana , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Rizosfera
8.
Mol Plant Microbe Interact ; 32(10): 1270-1272, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31063048

RESUMO

Fusarium wilt of banana is caused by the soilborne fungal pathogen Fusarium oxysporum f. sp. cubense. We generated two chromosome-level assemblies of F. oxysporum f. sp. cubense race 1 and tropical race 4 strains using single-molecule real-time sequencing. The F. oxysporum f. sp. cubense race 1 and tropical race 4 assemblies had 35 and 29 contigs with contig N50 lengths of 2.08 and 4.28 Mb, respectively. These two new references genomes represent a greater than 100-fold improvement over the contig N50 statistics of the previous short-read-based F. oxysporum f. sp. cubense assemblies. The two high-quality assemblies reported here will be a valuable resource for the comparative analysis of F. oxysporum f. sp. cubense races at the pathogenic level.


Assuntos
Fusarium , Genoma Fúngico , Fusarium/classificação , Fusarium/genética , Genoma Fúngico/genética , Musa/microbiologia , Análise de Sequência de DNA , Especificidade da Espécie
9.
Fungal Biol ; 123(5): 423-430, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31053331

RESUMO

Plant pathogens employ effectors as molecular weapons to manipulate host immunity and facilitate colonization. Fusarium oxysporum f. sp. cubense is the agent of wilt disease in banana plantlets and four races of the pathogen have been identified based on the cultivar specificity. A total of 9 SIX genes have been detected in the genome of Foc TR4 and 6 genes detected in Foc1. Among these SIX genes, SIX2 and SIX8 are only detected in Foc TR4, not identified in Foc1. Expression profiles analysis revealed that SIX genes of Foc TR4 are highly induced after inoculation to Cavendish banana plantlets. Virulence analysis of the SIX2 and SIX8 knock-out mutants showed that SIX8 is required for the virulence of Foc TR4 while SIX2 has no obvious functions. Over expression of SIX8-FLAG proteins in the SIX8 knock-out mutant partly restored the virulence. Western blot analysis suggested that SIX8 could be secreted into the extracellular space and a signal peptide resided the N-terminal polypeptide sequence. This study provides some clues for further research on mechanism of SIX8 in regulating virulence of Foc TR4.


Assuntos
Proteínas Fúngicas/metabolismo , Fusarium/patogenicidade , Musa/microbiologia , Doenças das Plantas/microbiologia , Fatores de Virulência/metabolismo , Proteínas Fúngicas/genética , Fusarium/genética , Fusarium/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Técnicas de Inativação de Genes , Teste de Complementação Genética , Fatores de Virulência/genética
10.
J Microbiol Biotechnol ; 29(5): 794-808, 2019 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-31030454

RESUMO

Bacillus velezensis strain WRN014 was isolated from banana fields in Hainan, China. Bacillus velezensis is an important member of the plant growth-promoting rhizobacteria (PGPR) which can enhance plant growth and control soil-borne disease. The complete genome of Bacillus velezensis WRN014 was sequenced by combining Illumina Hiseq 2500 system and Pacific Biosciences SMRT high-throughput sequencing technologies. Then, the genome of Bacillus velezensis WRN014, together with 45 other completed genome sequences of the Bacillus velezensis strains, were comparatively studied. The genome of Bacillus velezensis WRN014 was 4,063,541bp in length and contained 4,062 coding sequences, 9 genomic islands and 13 gene clusters. The results of comparative genomic analysis provide evidence that (i) The 46 Bacillus velezensis strains formed 2 obviously closely related clades in phylogenetic trees. (ii) The pangenome in this study is open and is increasing with the addition of new sequenced genomes. (iii) Analysis of single nucleotide polymorphisms (SNPs) revealed local diversification of the 46 Bacillus velezensis genomes. Surprisingly, SNPs were not evenly distributed throughout the whole genome. (iv) Analysis of gene clusters revealed that rich gene clusters spread over Bacillus velezensis strains and some gene clusters are conserved in different strains. This study reveals that the strain WRN014 and other Bacillus velezensis strains have potential to be used as PGPR and biopesticide.


Assuntos
Bacillus/genética , Genes Bacterianos/genética , Sequenciamento Completo do Genoma/métodos , Bacillus/classificação , Bacillus/isolamento & purificação , Sequência de Bases , China , Mapeamento Cromossômico , DNA Bacteriano/análise , DNA Bacteriano/genética , Variação Genética , Genoma Bacteriano , Família Multigênica , Musa/microbiologia , Mutação , Filogenia , Desenvolvimento Vegetal , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único , Metabolismo Secundário/genética , Análise de Sequência de DNA
11.
Plant Dis ; 103(4): 721-728, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30777802

RESUMO

Panama disease caused by Fusarium oxysporum f. sp. cubense has devastated banana production worldwide. This work aimed to determine effective disinfectants against two races of F. oxysporum f. sp. cubense, race 1 and tropical race 4 (TR4), for implementation with on-farm biosecurity procedures against this disease following the outbreak of TR4 in North Queensland in 2015. A total of 32 commercial disinfectants were screened and their activity was assessed after ≤30 s, 5 min, 30 min, and 24 h of contact with an F. oxysporum f. sp. cubense suspension containing 105 chlamydospores/ml without and with soil added (0.05 g/ml). Of the disinfectants tested, the quaternary ammonium compounds containing ≥10% active ingredient were found to be the most effective against both F. oxysporum f. sp. cubense races. These products, when used at a 1:100 dilution, completely inhibited the survival of all F. oxysporum f. sp. cubense propagules across all the contact times regardless of the absence or presence of soil. The bioflavonoid product EvoTech 213 and bleach (10% sodium hypochlorite) used at a 1:10 dilution also eliminated all F. oxysporum f. sp. cubense propagules across all the contact times. None of the detergent-based or miscellaneous products tested were completely effective against both F. oxysporum f. sp. cubense races even used at a 1:10 dilution. Soil decreases the efficacy of disinfectants and therefore must be removed from contaminated items before treatments are applied.


Assuntos
Desinfetantes , Microbiologia de Alimentos , Fusarium , Desinfetantes/farmacologia , Desinfetantes/normas , Microbiologia de Alimentos/métodos , Fusarium/efeitos dos fármacos , Musa/microbiologia , Doenças das Plantas/prevenção & controle , Queensland
12.
Microbiol Res ; 220: 12-20, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30744815

RESUMO

Banana is the second largest export crop in Colombia. To meet the demand of international markets, high amounts of chemical fertilizers are required, which represent high costs and can be hazardous to the environment. Plant growth promoting rhizobacteria (PGPR) can, at least partially, replace chemical fertilizers. In this paper, we evaluated the effect of nine PGPR of the genera Bacillus and Pseudomonas on banana growth. Banana seedlings were produced through tissue culture and acclimatized in the greenhouse core. Plants were inoculated with the rhizobacteria and growth parameters (plant height, leaf number, leaf area, pseudostem thickness, root and shoot fresh weight, root and shoot dry weight) were assessed after 55 days. The two best performing PGPR, Bs006 and Ps006 previously identified as Bacillus amyloliquefaciens and Pseudomonas fluorescens, respectively, promoted banana growth similarly or even slightly superior to 100% chemical fertilization, and were selected for further characterization of root colonization by both eletron microscopy and confocal microscopy of fluorescence in situ hybridization (FISH)-stained root tissues. Both P. fluorescens Ps006 and B. amyloquifaciens Bs006 showed ability to colonize banana roots, but Bs006 appeared faster than Ps006 in the colonization dynamics. This work demonstrated that inoculation of rhizobacteria Bacillus amyloliquefaciens Bs006 and Pseudomonas fluorescens Ps006 could partially replace the chemical fertilization of tissue cultured banana plants, and therefore could be used for the formulation of a new biofertilizer.


Assuntos
Bacillus amyloliquefaciens/fisiologia , Musa/crescimento & desenvolvimento , Musa/microbiologia , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Pseudomonas fluorescens/fisiologia , Bacillus amyloliquefaciens/genética , Bacillus amyloliquefaciens/isolamento & purificação , Colômbia , Fertilizantes , Hibridização in Situ Fluorescente , Microscopia Eletrônica de Varredura , Folhas de Planta/crescimento & desenvolvimento , Pseudomonas fluorescens/genética , Pseudomonas fluorescens/isolamento & purificação , Plântula , Solo/química , Microbiologia do Solo
13.
J Agric Food Chem ; 67(5): 1371-1380, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30624923

RESUMO

The antibacterial efficiency and synergistic mechanisms of novel formulated eugenol entrapped ethosome nanoparticles (ELG-NPs) against fruit anthracnose were investigated. The results showed that concentrations of eugenol and ethanol significantly influenced the particle size and entrapment efficiency of nanoethosome, and the particle size significantly influenced the antibacterial effect. Superior ELG-NPs with optimized process (0.5% eugenol, 2% lecithin, and 30% ethanol) were obtained with a size of 44.21 nm and entrapment efficiency of 82%. ELG-NPs exhibited an antibacterial activity (>93%) against fruit pathogens that was greater than that of free eugenol and showed 100% inhibition of the anthracnose incidence in postharvest loquat after 6 d. The permeability study, first visualized in banana cortex with fluorescent indicators, demonstrated that eugenol delivered to the interior with ELG-NPs was 6-fold higher than that of free eugenol. ELG-NPs showed a satisfactory slow-release and prolonged antibacterial action. This work provides a promising strategy for disease controls in agricultural, food, cosmetic, and medical areas.


Assuntos
Antibacterianos/farmacologia , Preparações de Ação Retardada/farmacologia , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Eugenol/farmacologia , Lipossomos/química , Musa/microbiologia , Doenças das Plantas/microbiologia , Antibacterianos/química , Preparações de Ação Retardada/química , Sistemas de Liberação de Medicamentos/instrumentação , Eugenol/química , Frutas/microbiologia , Testes de Sensibilidade Microbiana , Nanopartículas/química , Tamanho da Partícula , Permeabilidade
14.
Phytopathology ; 108(10): 1184-1195, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29726762

RESUMO

Black leaf streak disease (BLSD), caused by the fungus Mycosphaerella fijiensis, is an important threat to banana production. Although its control relies on costly and unsustainable use of fungicides, ecological regulation of BLSD linked to field-scale plant diversity has received little attention. We monitored banana phytometers in plots in banana-based fields where no fungicides were applied. Within each plot, we measured plant richness in three strata, canopy openness, necrotic leaf removal, Musa abundance and richness. We quantified ecological regulation of five BLSD parameters (inoculum sources, spore abundance, lesion density, incubation time, and the area under the disease progression curve) and identified, using structural equation modeling, the characteristics of the plant community and the mechanisms likely responsible for the regulation. Regulation occurred, but most effectively before lesion formation, and was mainly related to plant richness between 1.5 and 5m high. A barrier effect, rather than a dilution effect, more likely limited spore abundance. Our results support the hypothesis that the potential effects of plant richness on leaf-scale microclimate variability and on the diversity of epiphyllic microorganisms are involved in the regulation of incubation time and lesion density. Field-scale management of plant diversity may be a promising lever to foster ecological regulation of BLSD.


Assuntos
Ascomicetos/fisiologia , Biodiversidade , Musa/microbiologia , Doenças das Plantas/microbiologia , Agricultura , Ascomicetos/patogenicidade , Costa Rica , Musa/genética , Folhas de Planta/microbiologia
15.
Cell Mol Biol (Noisy-le-grand) ; 64(4): 52-58, 2018 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-29641375

RESUMO

Anthracnose of banana is incited by Colletotrichum  musae. It is recognized as one the most destructive diseases of mature and immature banana fruits, resulting in huge economic losses all over the world. Present research deals with screening some oils both in vitro and in vivo for their antifungal activity against C.musae. Clove oil (0.1µl/ml) completely arrested the conidial germination and mycelial growth of C. musae. Fenugreek and almond oil exhibited significant inhibition of mycelial growth, 61% and 57% at a concentration of 2µl/ml. However, olive oil was least inhibitory on the test fungi. Clove oil also a showed marked reduction in anthracnose lesions on banana fruits, thereby suggesting disease control. Scanning electron microscopy revealed severely damaged mycelium and conidia. FTIR studies show the presence of important bands representing phenols, terpenes, aldehydes, and ketones. Based on our findings; clove, fenugreek and almond oil demonstrated fungicidal and fungistatic activities against anthracnose pathogen. Hence, these oils can be considered as potential alternatives to chemical treatments.


Assuntos
Antifúngicos/farmacologia , Óleo de Cravo/farmacologia , Colletotrichum/efeitos dos fármacos , Azeite de Oliva/farmacologia , Doenças das Plantas/microbiologia , Óleos Vegetais/farmacologia , Animais , Antifúngicos/química , Óleo de Cravo/química , Colletotrichum/isolamento & purificação , Frutas/microbiologia , Humanos , Musa/microbiologia , Micélio/efeitos dos fármacos , Azeite de Oliva/química , Óleos Vegetais/química , Esporos Fúngicos/efeitos dos fármacos , Trigonella/química
16.
Can J Microbiol ; 64(5): 349-357, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29420915

RESUMO

The ascomycete fungus Fusarium oxysporum f.sp. cubense race 4 (Foc TR4) causes vascular wilt diseases in banana (Musa spp.). In the present study, the role of SGE1 in regulating growth, conidiation, and pathogenicity of Foc TR4 was investigated. Deletion of SGE1 did not influence vegetative growth but impaired the conidiation of Foc TR4. Besides, the SGE1 deletion mutant basically lost pathogenicity on banana plantlets. Observation under the microscope indicated that the penetration and colonization processes were severely impaired in the SGE1 deletion mutant. Proteomics analysis suggested that SGE1 regulated the production of a series of proteins of Foc TR4. Taken together, our results suggest that SGE1 plays an important role in regulating conidiation and pathogenicity in fungal pathogen Foc TR4.


Assuntos
Proteínas Fúngicas/genética , Fusarium/fisiologia , Fatores de Transcrição/genética , Proteínas Fúngicas/metabolismo , Fusarium/patogenicidade , Técnicas de Inativação de Genes , Musa/microbiologia , Doenças das Plantas/microbiologia , Raízes de Plantas/microbiologia , Esporos Fúngicos , Fatores de Transcrição/metabolismo , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
17.
Int J Mol Sci ; 19(2)2018 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-29364855

RESUMO

Banana Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is one of the most destructive soil-borne diseases. In this study, young tissue-cultured plantlets of banana (Musa spp. AAA) cultivars differing in Foc susceptibility were used to reveal their differential responses to this pathogen using digital gene expression (DGE). Data were evaluated by various bioinformatic tools (Venn diagrams, gene ontology (GO) annotation and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses) and immunofluorescence labelling method to support the identification of gene candidates determining the resistance of banana against Foc. Interestingly, we have identified MaWRKY50 as an important gene involved in both constitutive and induced resistance. We also identified new genes involved in the resistance of banana to Foc, including several other transcription factors (TFs), pathogenesis-related (PR) genes and some genes related to the plant cell wall biosynthesis or degradation (e.g., pectinesterases, ß-glucosidases, xyloglucan endotransglucosylase/hydrolase and endoglucanase). The resistant banana cultivar shows activation of PR-3 and PR-4 genes as well as formation of different constitutive cell barriers to restrict spreading of the pathogen. These data suggest new mechanisms of banana resistance to Foc.


Assuntos
Fusarium , Regulação da Expressão Gênica de Plantas , Musa/genética , Musa/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Transcriptoma , Biologia Computacional/métodos , Resistência à Doença , Suscetibilidade a Doenças , Imunofluorescência , Perfilação da Expressão Gênica , Ontologia Genética , Anotação de Sequência Molecular , Raízes de Plantas/genética , Reação em Cadeia da Polimerase
18.
Mol Plant Pathol ; 19(3): 525-536, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28677256

RESUMO

TAXONOMY: Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; currently classified as X. campestris pv. musacearum (Xcm). However, fatty acid methyl ester analysis and genetic and genomic evidence suggest that this pathogen is X. vasicola and resides in a separate pathovar. ISOLATION AND DETECTION: Xcm can be isolated on yeast extract peptone glucose agar (YPGA), cellobiose cephalexin agar and yeast extract tryptone sucrose agar (YTSA) complemented with 5-fluorouracil, cephalexin and cycloheximide to confer semi-selectivity. Xcm can also be identified using direct antigen coating enzyme-linked immunosorbent assay (DAC-ELISA), species-specific polymerase chain reaction (PCR) using GspDm primers and lateral flow devices that detect latent infections. HOST RANGE: Causes Xanthomonas wilt on plants belonging to the Musaceae, primarily banana (Musa acuminata), plantain (M. acuminata × balbisiana) and enset (Ensete ventricosum). DIVERSITY: There is a high level of genetic homogeneity within Xcm, although genome sequencing has revealed two major sublineages. SYMPTOMS: Yellowing and wilting of leaves, premature fruit ripening and dry rot, bacterial exudate from cut stems. DISTRIBUTION: Xcm has only been found in African countries, namely Burundi, Ethiopia, Democratic Republic of the Congo, Kenya, Rwanda, Tanzania and Uganda. ECOLOGY AND EPIDEMIOLOGY: Xcm is transmitted by insects, bats, birds and farming implements. Long-distance dispersal of the pathogen is by the transportation of latently infected plants into new areas. MANAGEMENT: The management of Xcm has relied on cultural practices that keep the pathogen population at tolerable levels. Biotechnology programmes have been successful in producing resistant banana plants. However, the deployment of such genetic material has not as yet been achieved in farmers' fields, and the sustainability of transgenic resistance remains to be addressed.


Assuntos
Musa/microbiologia , Plantago/microbiologia , Xanthomonas campestris/genética , Xanthomonas campestris/patogenicidade , África Central , África Oriental
19.
Int J Syst Evol Microbiol ; 68(1): 170-175, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29134937

RESUMO

Bogia coconut syndrome (BCS) is one of the lethal yellowing (LY)-type diseases associated with phytoplasma presence that are seriously threatening coconut cultivation worldwide. It has recently emerged, and is rapidly spreading in northern parts of the island of New Guinea. BCS-associated phytoplasmas collected in different regions were compared in terms of 16S rRNA gene sequences, revealing high identity among them represented by strain BCS-BoR. Comparative analysis of the 16S rRNA gene sequences revealed that BCS-BoR shared less than a 97.5 % similarity with other species of 'Candidatus Phytoplasma', with a maximum value of 96.08 % (with strain LY; GenBank accession no. U18747). This result indicates the necessity and propriety of a novel taxon for BCS phytoplasmas according to the recommendations of the IRPCM. Phylogenetic analysis was also conducted on 16S rRNA gene sequences, resulting in a monophyletic cluster composed of BCS-BoR and other LY-associated phytoplasmas. Other phytoplasmas on the island of New Guinea associated with banana wilt and arecanut yellow leaf diseases showed high similarities to BCS-BoR and were closely related to BCS phytoplasmas. Based on the uniqueness of their 16S rRNA gene sequences, a novel taxon 'Ca.Phytoplasma noviguineense' is proposed for these phytoplasmas found on the island of New Guinea, with strain BCS-BoR (GenBank accession no. LC228755) as the reference strain. The novel taxon is described in detail, including information on the symptoms of associated diseases and additional genetic features of the secY gene and rp operon.


Assuntos
Cocos/microbiologia , Musa/microbiologia , Filogenia , Phytoplasma/classificação , Doenças das Plantas/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ilhas , Nova Guiné , Phytoplasma/genética , Phytoplasma/isolamento & purificação , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
20.
Plant Dis ; 102(3): 552-560, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30673475

RESUMO

Banana Fusarium wilt is a major production constraint globally and a significant threat to the livelihoods of millions of people in East and Central Africa (ECA). A proper understanding of the diversity and population dynamics of the causal agent, Fusarium oxysporum f. sp. cubense (Foc), could be useful for the development of sustainable disease management strategies for the pathogen. The current study investigated the diversity of Foc in ECA using vegetative compatibility group (VCG) analysis, PCR-RFLPs of the ribosomal DNA's intergenic spacer region, as well as phylogenetic analysis of the elongation factor-1α gene. Six VCGs (0124, 0125, 0128, 01212, 01220, and 01222), which all belong to one lineage (Foc lineage VI), were widely distributed throughout the region. VCGs 0128 and 01220 are reported for the first time in Burundi, the Democratic Republic of Congo (DRC), Rwanda, Tanzania, and Uganda, while VCG 01212 is reported in the DRC and Rwanda. Isolates that did not belong to any of the known VCGs were identified as Foc lineage VI members by phylogenetic analysis and may represent novel VCGs. CAV 2734, a banana pathogen collected in Rwanda, clustered with nonpathogenic F. oxysporum isolates in lineage VIII. Results from this study will contribute significantly toward the implementation of banana Fusarium wilt disease management practices in the region, such as the restricted movement of infected planting material and the selective planting of resistant banana varieties.


Assuntos
Fusarium/genética , Variação Genética , Musa/microbiologia , Doenças das Plantas/microbiologia , África Central , África Oriental , Fusarium/classificação , Fusarium/isolamento & purificação , Fusarium/patogenicidade , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição
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