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1.
Plant Dis ; 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38720542

RESUMO

A real-time loop-mediated isothermal amplification (LAMP) assay for the detection of Bremia lactucae, the causal pathogen of Lettuce Downy Mildew (LDM), was developed and validated to aid in-field detection of airborne inoculum. Assay specificity was confirmed against a range of other pathogenic oomycete and fungal spp and sensitivity of the assay for the detection of DNA extracted from sporangia was evaluated. The B. lactucae LAMP assay reliably detected DNA equivalent to 1 spore/reaction (16.7 pg DNA/reaction). Following extraction of DNA from rotorod air-samplers to which sporangial suspensions were added, the assay reliably detected 25 sporangia/rotorod. Detection of airborne inoculum of B. lactucae collected through the season from air-samplers deployed in field plots infected with B. lactucae and also in commercial lettuce fields in Scotland over two growing seasons was assessed. The method can be deployed on samples collected from commercial lettuce production to inform disease management strategies and limit the use of unecessary prophylactic pesticide applications.

2.
Seizure ; 99: 1-7, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35500353

RESUMO

PURPOSE: We reviewed all prisoners diagnosed with epilepsy within a large UK category B prison: collecting demographic information and the prevalence and nature of their seizure disorder; and reviewed standards of their epilepsy healthcare provision. Previous work has highlighted poorer seizure control and limited access to specialist services in this patient group. METHODS: Fifty-five male prisoners with a previously established diagnosis of epilepsy were identified by the prison healthcare manager during the six-month audit period. Anonymised audit data was collected during clinical interviews undertaken by members of a regional specialist epilepsy service and recorded on a standardised proforma. Data collection occurred during six prison visits within the audit period. RESULTS: Point prevalence of epilepsy was 2%. Data suggest that demographics are complex and challenging in this patient group. We found increased rates of alcohol (40%) and drug (82%) misuse and mental health problems (85.5%). Just over one third of cases were prescribed medications with potential for misuse (diversion). Further optimization of anti-seizure medication (ASM) regimens was required in 67.3% of the study sample, with only 12.7% of cases being free of seizures for the last 12 months. Access to specialist epilepsy services was limited; only 38.2% had a specialist review in the last 12 months. Most cases (76.4%) did not recall receiving guidance on precautions that should be taken regarding duties or cell arrangements in relation to having a diagnosis of epilepsy. CONCLUSIONS: Tighter collaboration between prison healthcare and local NHS specialist services is recommended to optimise epilepsy healthcare in UK prison settings.


Assuntos
Epilepsia , Prisioneiros , Atenção à Saúde , Epilepsia/diagnóstico , Epilepsia/epidemiologia , Epilepsia/terapia , Humanos , Masculino , Prevalência , Prisões , Reino Unido/epidemiologia
3.
Phytopathology ; 112(2): 414-421, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34080915

RESUMO

Until recently, genotypes of Phytophthora infestans were regionally distributed in Europe, with populations in western Europe being dominated by clonal lineages and those in northern Europe being genetically diverse because of frequent sexual reproduction. However, since 2013 a new clonal lineage (EU_41_A2) has successfully established itself and expanded in the sexually recombining P. infestans populations of northern Europe. The objective of this study was to study phenotypic traits of the new clonal lineage of P. infestans, which may explain its successful establishment and expansion within sexually recombining populations. Fungicide sensitivity, aggressiveness, and virulence profiles of isolates of EU_41_A2 were analyzed and compared with those of the local sexual populations from Denmark, Norway, and Estonia. None of the phenotypic data obtained from the isolates collected from Denmark, Estonia, and Norway independently explained the invasive success of EU_41_A2 within sexual Nordic populations. Therefore, we hypothesize that the expansion of this new genotype could result from a combination of fitness traits and more favorable environmental conditions that have emerged in response to climate change.


Assuntos
Phytophthora infestans , Solanum tuberosum , Genótipo , Fenótipo , Phytophthora infestans/genética , Doenças das Plantas
4.
Phytopathology ; 109(4): 670-680, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30253119

RESUMO

Strains of Phytophthora infestans, the pathogen causing late blight of potato and tomato, are thought to be moved around the world through infected planting material. Since its first appearance in 1941, late blight has caused important losses to potato production in the eastern-Africa region (EAR). In the current study, the genetic structure of the population in Kenya, Uganda, Tanzania, Burundi, and Rwanda was characterized using 12-plex microsatellite markers with the aim of testing the hypothesis that a strain originating from Europe, 2_A1, has recently dominated the population in EAR. Analyses of 1,093 potato and 165 tomato samples collected between 2013 and 2016 revealed the dominance on potato in all countries of the 2_A1 clonal lineage. On tomato, a host-specialized form of the US-1 lineage appears to persist in Rwanda, Uganda, and Tanzania whereas, in Kenya, most samples from tomato (72.5%) were 2_A1. The US-1 lineage in Tanzania had two private alleles at the Pi02 marker, suggesting a possible independent introduction into the region. US-1 had higher genetic variability than 2_A1, consistent with the earlier establishment of the former. Continuous tracking of P. infestans population changes should help identify new virulent and aggressive strains, which would inform strategic disease management options.


Assuntos
Phytophthora infestans , Europa (Continente) , Genótipo , Quênia , Filogeografia , Phytophthora infestans/genética , Phytophthora infestans/patogenicidade , Doenças das Plantas , Tanzânia , Uganda
5.
Theor Appl Genet ; 131(6): 1287-1297, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29560514

RESUMO

KEY MESSAGE: A broad-spectrum late blight disease-resistance gene from Solanum verrucosum has been mapped to potato chromosome 9. The gene is distinct from previously identified-resistance genes. We have identified and characterised a broad-spectrum resistance to Phytophthora infestans from the wild Mexican species Solanum verrucosum. Diagnostic resistance gene enrichment (dRenSeq) revealed that the resistance is not conferred by previously identified nucleotide-binding, leucine-rich repeat genes. Utilising the sequenced potato genome as a reference, two complementary enrichment strategies that target resistance genes (RenSeq) and single/low-copy number genes (Generic-mapping enrichment Sequencing; GenSeq), respectively, were deployed for the rapid, SNP-based mapping of the resistance through bulked-segregant analysis. Both approaches independently positioned the resistance, referred to as Rpi-ver1, to the distal end of potato chromosome 9. Stringent post-enrichment read filtering identified a total of 64 informative SNPs that corresponded to the expected ratio for significant polymorphisms in the parents as well as the bulks. Of these, 61 SNPs are located on potato chromosome 9 and reside within 27 individual genes, which in the sequenced potato clone DM locate to positions 45.9 to 60.9 Mb. RenSeq- and GenSeq-derived SNPs within the target region were converted into allele-specific PCR-based KASP markers and further defined the position of the resistance to a 4.3 Mb interval at the bottom end of chromosome 9 between positions 52.62-56.98 Mb.


Assuntos
Resistência à Doença/genética , Genes de Plantas , Doenças das Plantas/genética , Solanum/genética , Mapeamento Cromossômico , DNA de Plantas/genética , Diploide , Marcadores Genéticos , Phytophthora infestans , Doenças das Plantas/microbiologia , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Solanum/microbiologia
6.
Front Plant Sci ; 7: 672, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27303410

RESUMO

The greatest threat to potato production world-wide is late blight, caused by the oomycete pathogen Phytophthora infestans. A screen of 126 wild diploid Solanum accessions from the Commonwealth Potato Collection (CPC) with P. infestans isolates belonging to the genotype 13-A2 identified resistances in the species S. bulbocastanum, S. capsicibaccatum, S. microdontum, S. mochiquense, S. okadae, S. pinnatisectum, S. polyadenium, S. tarijense, and S. verrucosum. Effector-omics, allele mining, and diagnostic RenSeq (dRenSeq) were utilized to investigate the nature of resistances in S. okadae accessions. dRenSeq in resistant S. okadae accessions 7129, 7625, 3762, and a bulk of 20 resistant progeny confirmed the presence of full-length Rpi-vnt1.1 under stringent mapping conditions and corroborated allele mining results in the accessions 7129 and 7625 as well as Avr-vnt1 recognition in transient expression assays. In contrast, susceptible S. okadae accession 3761 and a bulk of 20 susceptible progeny lacked sequence homology in the 5' end compared to the functional Rpi-vnt1.1 gene. Further evaluation of S. okadae accessions with P. infestans isolates that have a broad spectrum of virulence demonstrated that, although S. okadae accessions 7129, 7625, and 7629 contain functional Rpi-vnt1.1, they also carry a novel resistance gene. We provide evidence that existing germplasm collections are important sources of novel resistances and that "omic" technologies such as dRenSeq-based genomics and effector-omics are efficacious tools to rapidly explore the diversity within these collections.

7.
Glob Chang Biol ; 22(11): 3724-3738, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27214030

RESUMO

The impact of climate change on dispersal processes is largely ignored in risk assessments for crop diseases, as inoculum is generally assumed to be ubiquitous and nonlimiting. We suggest that consideration of the impact of climate change on the connectivity of crops for inoculum transmission may provide additional explanatory and predictive power in disease risk assessments, leading to improved recommendations for agricultural adaptation to climate change. In this study, a crop-growth model was combined with aerobiological models and a newly developed infection risk model to provide a framework for quantifying the impact of future climates on the risk of disease occurrence and spread. The integrated model uses standard meteorological variables and can be easily adapted to various crop pathosystems characterized by airborne inoculum. In a case study, the framework was used with data defining the spatial distribution of potato crops in Scotland and spatially coherent, probabilistic climate change data to project the future connectivity of crop distributions for Phytophthora infestans (causal agent of potato late blight) inoculum and the subsequent risk of infection. Projections and control recommendations are provided for multiple combinations of potato cultivar and CO2 emissions scenario, and temporal and spatial averaging schemes. Overall, we found that relative to current climatic conditions, the risk of late blight will increase in Scotland during the first half of the potato growing season and decrease during the second half. To guide adaptation strategies, we also investigated the potential impact of climate change-driven shifts in the cropping season. Advancing the start of the potato growing season by 1 month proved to be an effective strategy from both an agronomic and late blight management perspective.


Assuntos
Mudança Climática , Phytophthora infestans , Solanum tuberosum , Dióxido de Carbono , Produtos Agrícolas , Doenças das Plantas , Risco , Escócia , Estações do Ano
8.
Theor Appl Genet ; 127(3): 647-57, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24343200

RESUMO

Late blight of potato, caused by Phytophthora infestans, is one of the most economically important diseases worldwide, resulting in substantial yield losses when not adequately controlled by fungicides. Late blight was a contributory factor in The Great Irish Famine, and breeding for resistance to the disease began soon after. Several disease-resistant cultivars have subsequently been obtained, and amongst them Sárpo Mira is currently one of the most effective. The aim of this work was to extend the knowledge about the genetic basis of the late blight resistance in Sárpo Mira and to identify molecular markers linked to the resistance locus which would be useful for marker-assisted selection. A tetraploid mapping population from a Sárpo Mira × Maris Piper cross was phenotyped for foliar late blight resistance using detached leaflet tests. A locus with strong effect on late blight resistance was mapped at the end of chromosome XI in the vicinity of the R3 locus. Sárpo Mira's genetic map of chromosome XI contained 11 markers. Marker 45/XI exhibited the strongest linkage to the resistance locus and accounted for between 55.8 and 67.9% of variance in the mean resistance scores noted in the detached leaflet assays. This marker was used in molecular marker-facilitated gene pyramiding. Ten breeding lines containing a late blight resistance locus from cultivar Sárpo Mira and the Rpi-phu1 gene originating from the late blight resistant accession of Solanum phureja were obtained. These lines have extended the spectrum of late blight resistance compared with Sárpo Mira and it is expected that resistance in plants containing this gene pyramid will have enhanced durability.


Assuntos
Resistência à Doença/genética , Genes de Plantas , Phytophthora infestans , Solanum tuberosum/genética , Solanum tuberosum/microbiologia , Cruzamento , Mapeamento Cromossômico , Cromossomos de Plantas/genética , DNA de Plantas/genética , Ligação Genética , Marcadores Genéticos , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Folhas de Planta/microbiologia , Análise de Sequência de DNA
9.
PLoS Pathog ; 8(10): e1002940, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23055926

RESUMO

Pest and pathogen losses jeopardise global food security and ever since the 19(th) century Irish famine, potato late blight has exemplified this threat. The causal oomycete pathogen, Phytophthora infestans, undergoes major population shifts in agricultural systems via the successive emergence and migration of asexual lineages. The phenotypic and genotypic bases of these selective sweeps are largely unknown but management strategies need to adapt to reflect the changing pathogen population. Here, we used molecular markers to document the emergence of a lineage, termed 13_A2, in the European P. infestans population, and its rapid displacement of other lineages to exceed 75% of the pathogen population across Great Britain in less than three years. We show that isolates of the 13_A2 lineage are among the most aggressive on cultivated potatoes, outcompete other aggressive lineages in the field, and overcome previously effective forms of plant host resistance. Genome analyses of a 13_A2 isolate revealed extensive genetic and expression polymorphisms particularly in effector genes. Copy number variations, gene gains and losses, amino-acid replacements and changes in expression patterns of disease effector genes within the 13_A2 isolate likely contribute to enhanced virulence and aggressiveness to drive this population displacement. Importantly, 13_A2 isolates carry intact and in planta induced Avrblb1, Avrblb2 and Avrvnt1 effector genes that trigger resistance in potato lines carrying the corresponding R immune receptor genes Rpi-blb1, Rpi-blb2, and Rpi-vnt1.1. These findings point towards a strategy for deploying genetic resistance to mitigate the impact of the 13_A2 lineage and illustrate how pathogen population monitoring, combined with genome analysis, informs the management of devastating disease epidemics.


Assuntos
Genoma Fúngico , Phytophthora infestans/genética , Phytophthora infestans/patogenicidade , Doenças das Plantas/microbiologia , Solanum tuberosum/microbiologia , Produtos Agrícolas/microbiologia , Variações do Número de Cópias de DNA , Perfilação da Expressão Gênica , Genes de Plantas , Interações Hospedeiro-Patógeno , Imunidade Inata , Proteínas de Plantas/genética , Polimorfismo Genético , Análise de Sequência de DNA
10.
New Phytol ; 191(3): 763-776, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21539575

RESUMO

• A detailed molecular understanding of how oomycete plant pathogens evade disease resistance is essential to inform the deployment of durable resistance (R) genes. • Map-based cloning, transient expression in planta, pathogen transformation and DNA sequence variation across diverse isolates were used to identify and characterize PiAVR2 from potato late blight pathogen Phytophthora infestans. • PiAVR2 is an RXLR-EER effector that is up-regulated during infection, accumulates at the site of haustoria formation, and is recognized inside host cells by potato protein R2. Expression of PiAVR2 in a virulent P. infestans isolate conveys a gain-of-avirulence phenotype, indicating that this is a dominant gene triggering R2-dependent disease resistance. PiAVR2 presence/absence polymorphisms and differential transcription explain virulence on R2 plants. Isolates infecting R2 plants express PiAVR2-like, which evades recognition by R2. PiAVR2 and PiAVR2-like differ in 13 amino acids, eight of which are in the C-terminal effector domain; one or more of these determines recognition by R2. Nevertheless, few polymorphisms were observed within each gene in pathogen isolates, suggesting limited selection pressure for change within PiAVR2 and PiAVR2-like. • Our results direct a search for R genes recognizing PiAVR2-like, which, deployed with R2, may exert strong selection pressure against the P. infestans population.


Assuntos
Phytophthora infestans/patogenicidade , Doenças das Plantas/imunologia , Polimorfismo Genético/genética , Proteínas/metabolismo , Solanum tuberosum/fisiologia , Sequência de Aminoácidos , Mapeamento Cromossômico , Clonagem Molecular , Regulação da Expressão Gênica , Genes Dominantes/genética , Genes de Plantas/genética , Dados de Sequência Molecular , Phytophthora infestans/genética , Phytophthora infestans/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Folhas de Planta/fisiologia , Estrutura Terciária de Proteína , Proteínas/genética , Solanum/genética , Solanum tuberosum/genética , Solanum tuberosum/imunologia , Solanum tuberosum/microbiologia , Virulência/genética , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
11.
Theor Appl Genet ; 112(4): 744-51, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16395567

RESUMO

The R10 and R11 late blight differentials of Black (tetraploid clones 3681ad1 and 5008ab6) were crossed with the susceptible potato (Solanum tuberosum) cultivar Maris Piper and the progeny were assessed for blight resistance in a whole plant glasshouse test using race 1,2,3,4,6,7 of Phytophthora infestans. The disease scores for the R10 population displayed a continuous distribution whereas the progeny in the R11 population could be categorised as resistant or susceptible. A bulk segregant analysis using amplified fragment length polymorphism assays was done on the ten most resistant and ten most susceptible progeny in each population and two closely linked markers were found to be associated with resistance. R11 mapped to 8.5 cM from marker PAG/MAAG_172.3 and R10 mapped as a quantitative trait locus in which marker PAC/MATC_264.1 explained 56.9% of the variation in disease scores. The results were consistent with R10 and R11 being allelic versions of genes at the R3 locus on chromosome 11. The implications are discussed for mapping R-genes which fail to give complete immunity to a pathogen.


Assuntos
Mapeamento Cromossômico , Cromossomos de Plantas/genética , Genes de Plantas , Imunidade Inata/genética , Phytophthora/patogenicidade , Solanum tuberosum/genética , Solanum tuberosum/microbiologia , Alelos , Cruzamentos Genéticos , DNA de Plantas/genética , Marcadores Genéticos , Fenótipo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Locos de Características Quantitativas
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