RESUMO
Quinoa (Chenopodium quinoa Willd.) is a native American crop mainly grown in the Andes of Bolivia and Peru. During the last decades, the cultivation of quinoa has expanded to more than 125 countries. Since then, several diseases of quinoa have been characterized. A leaf disease was observed on quinoa plants growing in an experimental plot in Eastern Denmark in 2018. The symptoms produced by the associated fungi consisted of small yellow blotches on the upper surface of leaves with a pale chlorotic halo surrounding the lesion. These studies used a combination of morphology, molecular diagnostics, and pathogenicity tests to identify two different Alternaria species belonging to Alternaria sections Infectoriae and Alternata as the causal agent of observed disease symptoms. To the best of our knowledge, this is the first report of Alternaria spp. as foliar pathogens of quinoa. Our findings indicate the need for additional studies to determine potential risks to quinoa production.
Assuntos
Chenopodium quinoa , Chenopodium quinoa/microbiologia , Alternaria/genética , Peru , Folhas de Planta/microbiologiaRESUMO
BACKGROUND: Quinoa (Chenopodium quinoa Willd.) is an ancient grain crop that is tolerant to abiotic stress and has favorable nutritional properties. Downy mildew is the main disease of quinoa and is caused by infections of the biotrophic oomycete Peronospora variabilis Gaüm. Since the disease causes major yield losses, identifying sources of downy mildew tolerance in genetic resources and understanding its genetic basis are important goals in quinoa breeding. RESULTS: We infected 132 South American genotypes, three Danish cultivars and the weedy relative C. album with a single isolate of P. variabilis under greenhouse conditions and observed a large variation in disease traits like severity of infection, which ranged from 5 to 83%. Linear mixed models revealed a significant effect of genotypes on disease traits with high heritabilities (0.72 to 0.81). Factors like altitude at site of origin or seed saponin content did not correlate with mildew tolerance, but stomatal width was weakly correlated with severity of infection. Despite the strong genotypic effects on mildew tolerance, genome-wide association mapping with 88 genotypes failed to identify significant marker-trait associations indicating a polygenic architecture of mildew tolerance. CONCLUSIONS: The strong genetic effects on mildew tolerance allow to identify genetic resources, which are valuable sources of resistance in future quinoa breeding.
Assuntos
Chenopodium quinoa/genética , Chenopodium quinoa/microbiologia , Variação Genética , Peronospora/patogenicidade , Doenças das Plantas/microbiologia , Chenopodium album/microbiologia , Genoma de Planta , Estudo de Associação Genômica Ampla , Genótipo , Interações Hospedeiro-Patógeno/genética , Modelos Lineares , Peronospora/isolamento & purificação , Doenças das Plantas/etiologia , Doenças das Plantas/genética , Saponinas/análise , Sementes/química , América do Sul , Sequenciamento Completo do GenomaRESUMO
Antimicrobial resistance (AMR) is a serious threat to global public health, but obtaining representative data on AMR for healthy human populations is difficult. Here, we use metagenomic analysis of untreated sewage to characterize the bacterial resistome from 79 sites in 60 countries. We find systematic differences in abundance and diversity of AMR genes between Europe/North-America/Oceania and Africa/Asia/South-America. Antimicrobial use data and bacterial taxonomy only explains a minor part of the AMR variation that we observe. We find no evidence for cross-selection between antimicrobial classes, or for effect of air travel between sites. However, AMR gene abundance strongly correlates with socio-economic, health and environmental factors, which we use to predict AMR gene abundances in all countries in the world. Our findings suggest that global AMR gene diversity and abundance vary by region, and that improving sanitation and health could potentially limit the global burden of AMR. We propose metagenomic analysis of sewage as an ethically acceptable and economically feasible approach for continuous global surveillance and prediction of AMR.
Assuntos
Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos , Metagenoma , Esgotos/microbiologia , África , Ásia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Monitoramento Epidemiológico , Europa (Continente) , Humanos , Metagenômica/métodos , Consórcios Microbianos/efeitos dos fármacos , Consórcios Microbianos/genética , América do Norte , Oceania , Saúde da População , Fatores Socioeconômicos , América do SulRESUMO
Successful application of virus-induced gene silencing for functional genomics requires a virus vector that can initiate a systemic infection of the host plant. Agroinoculation of the pea early browning virus vectors pCAPE1 and pCAPE2 can establish infection in several genotypes of Medicago truncatula and can reduce target gene RNA levels to an extent that allows investigation of gene function.
Assuntos
Regulação da Expressão Gênica de Plantas , Inativação Gênica , Medicago truncatula/genética , Interferência de RNA , Genoma de Planta , Genômica/métodos , Medicago truncatula/microbiologia , Fenótipo , Plantas Geneticamente Modificadas , Plasmídeos/genéticaRESUMO
Silent transmission of Mycobacterium leprae, as evidenced by stable leprosy incidence rates in various countries, remains a health challenge despite the implementation of multidrug therapy worldwide. Therefore, the development of tools for the early diagnosis of M. leprae infection should be emphasised in leprosy research. As part of the continuing effort to identify antigens that have diagnostic potential, unique M. leprae peptides derived from predicted virulence-associated proteins (group IV.A) were identified using advanced genome pattern programs and bioinformatics. Based on human leukocyte antigen (HLA)-binding motifs, we selected 21 peptides that were predicted to be promiscuous HLA-class I T-cell epitopes and eight peptides that were predicted to be HLA-class II restricted T-cell epitopes for field-testing in Brazil, Ethiopia and Nepal. High levels of interferon (IFN)-γ were induced when peripheral blood mononuclear cells (PBMCs) from tuberculoid/borderline tuberculoid leprosy patients located in Brazil and Ethiopia were stimulated with the ML2055 p35 peptide. PBMCs that were isolated from healthy endemic controls living in areas with high leprosy prevalence (EChigh) in Ethiopia also responded to the ML2055 p35 peptide. The Brazilian EChigh group recognised the ML1358 p20 and ML1358 p24 peptides. None of the peptides were recognised by PBMCs from healthy controls living in non-endemic region. In Nepal, mixtures of these peptides induced the production of IFN-γ by the PBMCs of leprosy patients and EChigh. Therefore, the M. leprae virulence-associated peptides identified in this study may be useful for identifying exposure to M. leprae in population with differing HLA polymorphisms.
Assuntos
Humanos , Citocinas/imunologia , Epitopos de Linfócito T/imunologia , Mycobacterium leprae/patogenicidade , Virulência/imunologia , Brasil , Proteínas de Bactérias/imunologia , Biologia Computacional , Mapeamento de Epitopos , Etiópia , Mycobacterium leprae/imunologia , Mycobacterium leprae/isolamento & purificação , Mycobacterium leprae/virologia , Nepal , Fragmentos de Peptídeos/imunologia , Proteínas Recombinantes/imunologiaRESUMO
Silent transmission of Mycobacterium leprae, as evidenced by stable leprosy incidence rates in various countries, remains a health challenge despite the implementation of multidrug therapy worldwide. Therefore, the development of tools for the early diagnosis of M. leprae infection should be emphasised in leprosy research. As part of the continuing effort to identify antigens that have diagnostic potential, unique M. leprae peptides derived from predicted virulence-associated proteins (group IV.A) were identified using advanced genome pattern programs and bioinformatics. Based on human leukocyte antigen (HLA)-binding motifs, we selected 21 peptides that were predicted to be promiscuous HLA-class I T-cell epitopes and eight peptides that were predicted to be HLA-class II restricted T-cell epitopes for field-testing in Brazil, Ethiopia and Nepal. High levels of interferon (IFN)-γ were induced when peripheral blood mononuclear cells (PBMCs) from tuberculoid/borderline tuberculoid leprosy patients located in Brazil and Ethiopia were stimulated with the ML2055 p35 peptide. PBMCs that were isolated from healthy endemic controls living in areas with high leprosy prevalence (EChigh) in Ethiopia also responded to the ML2055 p35 peptide. The Brazilian EChigh group recognised the ML1358 p20 and ML1358 p24 peptides. None of the peptides were recognised by PBMCs from healthy controls living in non-endemic region. In Nepal, mixtures of these peptides induced the production of IFN-γ by the PBMCs of leprosy patients and EChigh. Therefore, the M. leprae virulence-associated peptides identified in this study may be useful for identifying exposure to M. leprae in population with differing HLA polymorphisms.