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Utami D, Meale SJ, Young AJ. Bacterial Leaf Spot Susceptibility Screening of Chili Pepper Cultivars Using qPCR Determination of Xanthomonas euvesicatoria pv. euvesicatoria Titers. PHYTOPATHOLOGY 2024; 114:681-689. [PMID: 38079287 DOI: 10.1094/phyto-12-22-0479-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Bacterial leaf spot is a serious disease of chili pepper (Capsicum spp.) caused by Xanthomonas euvesicatoria pv. euvesicatoria. Conventional resistance screening is time and resource intensive. It was considered that a quick and simple determination of cultivar susceptibility could be achieved through estimating bacterial titers of inoculated plants. A SYBR quantitative polymerase chain reaction (qPCR)-based assay was compared with conventional PCR, then used to detect and enumerate pathogen titers in serial dilutions and DNA extracted from infected plant leaves. The qPCR detection limit was approximately 1 CFU µl-1, 10 times more sensitive than conventional PCR. A linear correlation (R2 = 0.994) was obtained from the standard curve comparing plate-truthed serial dilutions of the pathogen with the qPCR cycle threshold. Six strains were used to inoculate cultivars Hugo and Warlock. One strain, X. euvesicatoria pv. euvesicatoria BRIP62403, was consistently the most virulent based on visual symptoms and pathogen titers in planta inferred by qPCR performed on DNA extracted from infected leaves 2 and 6 weeks postinoculation. Visual observations 6 weeks after inoculation were highly correlated (R2 = 0.8254) to pathogen titers. The qPCR method was used to categorize 20 chili pepper cultivars 2 weeks after inoculation. A high positive correlation (R2 = 0.6826) was observed between visual scoring and pathogen titers from 20 chili pepper cultivars, facilitating categorization of susceptible, intermediate, and resistant cultivars. The qPCR approach developed here facilitates susceptibility screening of chili pepper cultivars at an early stage of selection and could be readily adapted to a range of other pathosystems.
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Affiliation(s)
- Desi Utami
- School of Agriculture and Food Sustainability, Faculty of Science, The University of Queensland, Queensland, 4343, Australia
- Department of Agricultural Microbiology, Faculty of Agriculture, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
| | - Sarah J Meale
- School of Agriculture and Food Sustainability, Faculty of Science, The University of Queensland, Queensland, 4343, Australia
| | - Anthony J Young
- School of Agriculture and Food Sustainability, Faculty of Science, The University of Queensland, Queensland, 4343, Australia
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Reis Pereira M, dos Santos FN, Tavares F, Cunha M. Enhancing host-pathogen phenotyping dynamics: early detection of tomato bacterial diseases using hyperspectral point measurement and predictive modeling. FRONTIERS IN PLANT SCIENCE 2023; 14:1242201. [PMID: 37662158 PMCID: PMC10468592 DOI: 10.3389/fpls.2023.1242201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 07/27/2023] [Indexed: 09/05/2023]
Abstract
Early diagnosis of plant diseases is needed to promote sustainable plant protection strategies. Applied predictive modeling over hyperspectral spectroscopy (HS) data can be an effective, fast, cost-effective approach for improving plant disease diagnosis. This study aimed to investigate the potential of HS point-of-measurement (POM) data for in-situ, non-destructive diagnosis of tomato bacterial speck caused by Pseudomonas syringae pv. tomato (Pst), and bacterial spot, caused by Xanthomonas euvesicatoria (Xeu), on leaves (cv. cherry). Bacterial artificial infection was performed on tomato plants at the same phenological stage. A sensing system composed by a hyperspectral spectrometer, a transmission optical fiber bundle with a slitted probe and a white light source were used for spectral data acquisition, allowing the assessment of 3478 spectral points. An applied predictive classification model was developed, consisting of a normalizing pre-processing strategy allied with a Linear Discriminant Analysis (LDA) for reducing data dimensionality and a supervised machine learning algorithm (Support Vector Machine - SVM) for the classification task. The predicted model achieved classification accuracies of 100% and 74% for Pst and Xeu test set assessments, respectively, before symptom appearance. Model predictions were coherent with host-pathogen interactions mentioned in the literature (e.g., changes in photosynthetic pigment levels, production of bacterial-specific molecules, and activation of plants' defense mechanisms). Furthermore, these results were coherent with visual phenotyping inspection and PCR results. The reported outcomes support the application of spectral point measurements acquired in-vivo for plant disease diagnosis, aiming for more precise and eco-friendly phytosanitary approaches.
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Affiliation(s)
- Mafalda Reis Pereira
- Faculdade de Ciências da Universidade do Porto (FCUP), Rua do Campo Alegre, Porto, Portugal
- Institute for Systems and Computer Engineering, Technology and Science (INESC TEC), Campus da Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, Porto, Portugal
| | - Filipe Neves dos Santos
- Institute for Systems and Computer Engineering, Technology and Science (INESC TEC), Campus da Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, Porto, Portugal
| | - Fernando Tavares
- Faculdade de Ciências da Universidade do Porto (FCUP), Rua do Campo Alegre, Porto, Portugal
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal
| | - Mário Cunha
- Faculdade de Ciências da Universidade do Porto (FCUP), Rua do Campo Alegre, Porto, Portugal
- Institute for Systems and Computer Engineering, Technology and Science (INESC TEC), Campus da Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, Porto, Portugal
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A Pan-Global Study of Bacterial Leaf Spot of Chilli Caused by Xanthomonas spp. PLANTS 2022; 11:plants11172291. [PMID: 36079673 PMCID: PMC9460788 DOI: 10.3390/plants11172291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022]
Abstract
Bacterial Leaf Spot (BLS) is a serious bacterial disease of chilli (Capsicum spp.) caused by at least four different Xanthomonas biotypes: X. euvesicatoria pv. euvesicatoria, X. euvesicatoria pv. perforans, X. hortorum pv. gardneri, and X. vesicatoria. Symptoms include black lesions and yellow halos on the leaves and fruits, resulting in reports of up to 66% losses due to unsalable and damaged fruits. BLS pathogens are widely distributed in tropical and subtropical regions. Xanthomonas is able to survive in seeds and crop residues for short periods, leading to the infections in subsequent crops. The pathogen can be detected using several techniques, but largely via a combination of traditional and molecular approaches. Conventional detection is based on microscopic and culture observations, while a suite of Polymerase Chain Reaction (PCR) and Loop-Mediated Isothermal Amplification (LAMP) assays are available. Management of BLS is challenging due to the broad genetic diversity of the pathogens, a lack of resilient host resistance, and poor efficacy of chemical control. Some biological control agents have been reported, including bacteriophage deployment. Incorporating stable host resistance is a critical component in ongoing integrated management for BLS. This paper reviews the current status of BLS of chilli, including its distribution, pathogen profiles, diagnostic options, disease management, and the pursuit of plant resistance.
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DNA Markers for Detection and Genotyping of Xanthomonas euroxanthea. Microorganisms 2022; 10:microorganisms10061078. [PMID: 35744598 PMCID: PMC9227330 DOI: 10.3390/microorganisms10061078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/19/2022] [Accepted: 05/19/2022] [Indexed: 12/04/2022] Open
Abstract
Xanthomonas euroxanthea is a bacterial species encompassing both pathogenic and non-pathogenic strains and is frequently found colonizing the same host plants as X. arboricola. This presents the need to develop a detection and genotyping assay able to track these bacteria in microbial consortia with other xanthomonads. Eight X. euroxanthea-specific DNA markers (XEA1-XEA8) were selected by comparative genomics and validated in silico regarding their specificity and consistency using BLASTn, synteny analysis, CG content, codon usage (CAI/eCAI values) and genomic proximity to plasticity determinants. In silico, the selected eight DNA markers were found to be specific and conserved across the genomes of 11 X. euroxanthea strains, and in particular, five DNA markers (XEA4, XEA5, XEA6, XEA7 and XEA8) were unfailingly found in these genomes. A multiplex of PCR targeting markers XEA1 (819 bp), XEA8 (648 bp) and XEA5 (295 bp) was shown to successfully detect X. euroxanthea down to 1 ng of DNA (per PCR reaction). The topology of trees generated with the concatenated sequences of three markers (XEA5, XEA6 and XEA8) and four housekeeping genes (gyrB, rpoD, fyuA and acnB) underlined the equal discriminatory power of these features and thus the suitability of the DNA markers to discriminate X. euroxanthea lineages. Overall, this study displays a DNA-marker-based method for the detection and genotyping of X. euroxanthea strains, contributing to monitoring for its presence in X. arboricola-colonizing habitats. The present study proposes a workflow for the selection of species-specific detection markers. Prospectively, this assay could contribute to unveil alternative host species of Xanthomonas euroxanthea; and improve the control of phytopathogenic strains.
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Catara V, Cubero J, Pothier JF, Bosis E, Bragard C, Đermić E, Holeva MC, Jacques MA, Petter F, Pruvost O, Robène I, Studholme DJ, Tavares F, Vicente JG, Koebnik R, Costa J. Trends in Molecular Diagnosis and Diversity Studies for Phytosanitary Regulated Xanthomonas. Microorganisms 2021; 9:862. [PMID: 33923763 PMCID: PMC8073235 DOI: 10.3390/microorganisms9040862] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 11/17/2022] Open
Abstract
Bacteria in the genus Xanthomonas infect a wide range of crops and wild plants, with most species responsible for plant diseases that have a global economic and environmental impact on the seed, plant, and food trade. Infections by Xanthomonas spp. cause a wide variety of non-specific symptoms, making their identification difficult. The coexistence of phylogenetically close strains, but drastically different in their phenotype, poses an added challenge to diagnosis. Data on future climate change scenarios predict an increase in the severity of epidemics and a geographical expansion of pathogens, increasing pressure on plant health services. In this context, the effectiveness of integrated disease management strategies strongly depends on the availability of rapid, sensitive, and specific diagnostic methods. The accumulation of genomic information in recent years has facilitated the identification of new DNA markers, a cornerstone for the development of more sensitive and specific methods. Nevertheless, the challenges that the taxonomic complexity of this genus represents in terms of diagnosis together with the fact that within the same bacterial species, groups of strains may interact with distinct host species demonstrate that there is still a long way to go. In this review, we describe and discuss the current molecular-based methods for the diagnosis and detection of regulated Xanthomonas, taxonomic and diversity studies in Xanthomonas and genomic approaches for molecular diagnosis.
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Affiliation(s)
- Vittoria Catara
- Department of Agriculture, Food and Environment, University of Catania, 95125 Catania, Italy
| | - Jaime Cubero
- National Institute for Agricultural and Food Research and Technology (INIA), 28002 Madrid, Spain;
| | - Joël F. Pothier
- Environmental Genomics and Systems Biology Research Group, Institute for Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), 8820 Wädenswil, Switzerland;
| | - Eran Bosis
- Department of Biotechnology Engineering, ORT Braude College of Engineering, Karmiel 2161002, Israel;
| | - Claude Bragard
- UCLouvain, Earth & Life Institute, Applied Microbiology, 1348 Louvain-la-Neuve, Belgium;
| | - Edyta Đermić
- Department of Plant Pathology, Faculty of Agriculture, University of Zagreb, 10000 Zagreb, Croatia;
| | - Maria C. Holeva
- Benaki Phytopathological Institute, Scientific Directorate of Phytopathology, Laboratory of Bacteriology, GR-14561 Kifissia, Greece;
| | - Marie-Agnès Jacques
- IRHS, INRA, AGROCAMPUS-Ouest, Univ Angers, SFR 4207 QUASAV, 49071 Beaucouzé, France;
| | - Francoise Petter
- European and Mediterranean Plant Protection Organization (EPPO/OEPP), 75011 Paris, France;
| | - Olivier Pruvost
- CIRAD, UMR PVBMT, F-97410 Saint Pierre, La Réunion, France; (O.P.); (I.R.)
| | - Isabelle Robène
- CIRAD, UMR PVBMT, F-97410 Saint Pierre, La Réunion, France; (O.P.); (I.R.)
| | | | - Fernando Tavares
- CIBIO—Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO-Laboratório Associado, Universidade do Porto, 4485-661 Vairão, Portugal; or
- FCUP-Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | | | - Ralf Koebnik
- Plant Health Institute of Montpellier (PHIM), Univ Montpellier, Cirad, INRAe, Institut Agro, IRD, 34398 Montpellier, France;
| | - Joana Costa
- Centre for Functional Ecology-Science for People & the Planet, Department of Life Sciences, University of Coimbra, 300-456 Coimbra, Portugal
- Laboratory for Phytopathology, Instituto Pedro Nunes, 3030-199 Coimbra, Portugal
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Mendes RJ, Luz JP, Santos C, Tavares F. CRISPR genotyping as complementary tool for epidemiological surveillance of Erwinia amylovora outbreaks. PLoS One 2021; 16:e0250280. [PMID: 33861806 PMCID: PMC8051791 DOI: 10.1371/journal.pone.0250280] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/02/2021] [Indexed: 12/12/2022] Open
Abstract
Fire blight is a destructive plant disease caused by Erwinia amylovora affecting pome fruit trees, and responsible for large yield declines, long phytosanitary confinements, and high economic losses. In Portugal, the first major fire blight outbreaks occurred in 2010 and 2011, and although later considered eradicated, the emergence of other outbreaks in recent years stressed the need to characterize the E. amylovora populations associated with these outbreaks. In this regard, CRISPR genotyping, assessment of three virulence markers, and semi-quantitative virulence bioassays, were carried out to determine the genotype, and assess the virulence of thirty-six E. amylovora isolates associated with outbreaks occurring between 2010 and 2017 and affecting apple and pear orchards located in the country central-west, known as the main producing region of pome fruits in Portugal. The data gathered reveal that 35 E. amylovora isolates belong to one of the widely-distributed CRISPR genotypes (5-24-38 / D-a-α) regardless the host species, year and region. Ea 680 was the single isolate revealing a new CRISPR genotype due to a novel CR2 spacer located closer to the leader sequence and therefore thought to be recently acquired. Regarding pathogenicity, although dot-blot hybridization assays showed the presence of key virulence factors, namely hrpL (T3SS), hrpN (T3E) and amsG from the amylovoran biosynthesis operon in all E. amylovora isolates studied, pathogenicity bioassays on immature pear slices allowed to distinguish four virulence levels, with most of the isolates revealing an intermediate to severe virulence phenotype. Regardless the clonal population structure of the E. amylovora associated to the outbreaks occurring in Portugal between 2010 and 2017, the different virulence phenotypes, suggests that E. amylovora may have been introduced at different instances into the country. This is the first study regarding E. amylovora in Portugal, and it discloses a novel CRISPR genotype for this bacterium.
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Affiliation(s)
- Rafael J. Mendes
- Faculty of Sciences of University of Porto, Porto, Portugal
- LAQV/REQUIMTE, Faculty of Sciences of University of Porto, Porto, Portugal
- CITAB—Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
- CIBIO–Research Centre in Biodiversity and Genetic Resources, InBIO, Associated Laboratory, University of Porto, Campus Agrário de Vairão, Vairão, Portugal
| | - João Pedro Luz
- QRural, Polytechnic Institute of Castelo Branco, School of Agriculture, Castelo Branco, Portugal
| | - Conceição Santos
- Faculty of Sciences of University of Porto, Porto, Portugal
- LAQV/REQUIMTE, Faculty of Sciences of University of Porto, Porto, Portugal
| | - Fernando Tavares
- Faculty of Sciences of University of Porto, Porto, Portugal
- CIBIO–Research Centre in Biodiversity and Genetic Resources, InBIO, Associated Laboratory, University of Porto, Campus Agrário de Vairão, Vairão, Portugal
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Martins L, Fernandes C, Albuquerque P, Tavares F. Assessment of Xanthomonas arboricola pv. juglandis Bacterial Load in Infected Walnut Fruits by Quantitative PCR. PLANT DISEASE 2019; 103:2577-2586. [PMID: 31347945 DOI: 10.1094/pdis-12-18-2253-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Xanthomonas arboricola pv. juglandis is the etiologic agent of important walnut (Juglans regia L.) diseases, causing severe fruit drop and high economic losses in walnut production regions. Rapid diagnostics and knowledge of bacterial virulence fitness are key to hinder disease progression and apply timely phytosanitary measures. This work describes an X. arboricola pv. juglandis-specific real-time quantitative PCR (qPCR) using X. arboricola pv. juglandis-specific DNA markers to quantify the bacterial load in infected walnut plant tissues. Method validation was achieved using calibration curves obtained with serial dilutions of X. arboricola pv. juglandis chromosomal DNA and standard curves obtained from walnut samples spiked with X. arboricola pv. juglandis cells. High correlations (R2 > 0.990 and > 0.995) and low limits of detection (35 chromosomes/qPCR reaction and 2.7 CFU/qPCR reaction) were obtained for both markers considering the calibration and standard curves, respectively. Assessment of qPCR repeatability, reproducibility, and specificity allowed us to demonstrate the reliability and consistency of the method. Furthermore, in planta quantification of X. arboricola pv. juglandis bacterial load using infected walnut fruit samples showed a higher detection resolution compared with standard PCR detection. By allowing quantification of virulence fitness of distinct X. arboricola pv. juglandis strains in planta, the proposed qPCR method may contribute to assertive risk assessment of walnut diseases caused by X. arboricola pv. juglandis and ultimately help to improve phytosanitary practices.
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Affiliation(s)
- Leonor Martins
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO - Laboratório Associado, Universidade do Porto, Vairão, Portugal
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal
| | - Camila Fernandes
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO - Laboratório Associado, Universidade do Porto, Vairão, Portugal
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal
- INIAV - Instituto Nacional de Investigação Agrária e Veterinária, Quinta do Marquês, Oeiras, Portugal
| | - Pedro Albuquerque
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO - Laboratório Associado, Universidade do Porto, Vairão, Portugal
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal
| | - Fernando Tavares
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO - Laboratório Associado, Universidade do Porto, Vairão, Portugal
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal
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Molecular Epidemiology of Xanthomonas perforans Outbreaks in Tomato Plants from Transplant to Field as Determined by Single-Nucleotide Polymorphism Analysis. Appl Environ Microbiol 2019; 85:AEM.01220-19. [PMID: 31253682 DOI: 10.1128/aem.01220-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 06/25/2019] [Indexed: 01/15/2023] Open
Abstract
Outbreaks of bacterial spot on tomato (BST) caused by Xanthomonas perforans are a major concern for sustainable crop production. BST is a common occurrence in tomato transplants grown for field production. We hypothesized that BST outbreaks in commercial fields originate from X. perforans strains inadvertently introduced from commercial transplant facilities. To test this hypothesis, we used a genome-wide single-nucleotide polymorphism (SNP) analysis to characterize X. perforans strains recovered from tomato transplant facilities and fields in commercial production areas. X. perforans strains were isolated from symptomatic transplants prior to roguing at two commercial transplant growers. Then, the same groups of transplants were tracked to commercial fields to recover X. perforans strains from diseased plants prior to harvest. Whole-genome sequencing was carried out on 84 strains isolated from transplant and field plants from Florida and South Carolina. SNPs were called using three reference strains that represented the genetic variation of the sampled strains. Field strains showing genetic similarity to transplant strains had a difference of 2 to 210 SNPs. Transplant and field strains clustered together by grower within each phylogenomic group, consistent with expectations. The range of genetic divergence among strains isolated from field plants was similar to the range obtained from strains on transplants. Using the range of genetic variation observed in transplants, we estimate that 60% to 100% of field strains were an extension of the transplant strain population. Our results stress the importance of BST management to reduce X. perforans movement from transplant to field and to minimize subsequent disease outbreaks.IMPORTANCE Current management of Xanthomonas perforans on tomato plants mainly relies on the frequent application of pesticides. However, the lack of effective pesticides and the development of strain tolerance to certain bactericides limit the ability to control outbreaks in production fields. Better knowledge of probable sources of X. perforans inoculum during tomato production is required to refine management strategies. Tomato plants are typically established in the field using transplants. This study aimed to determine if strains from field epidemics were coming from transplant facilities or resulted from local field outbreaks. The overall goal was to identify potential sources of inoculum and subsequently develop strategies to reduce carryover from transplant production to the field. Our results indicate that tomato producers should shift disease management efforts to transplant facilities to reduce disease in the field. Improved transplant health should reduce the likelihood of bacterial spot outbreaks and subsequently reduce pesticide usage in the field.
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Denancé N, Briand M, Gaborieau R, Gaillard S, Jacques MA. Identification of genetic relationships and subspecies signatures in Xylella fastidiosa. BMC Genomics 2019; 20:239. [PMID: 30909861 PMCID: PMC6434890 DOI: 10.1186/s12864-019-5565-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/25/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The phytopathogenic bacterium Xylella fastidiosa was thought to be restricted to the Americas where it infects and kills numerous hosts. Its detection worldwide has been blooming since 2013 in Europe and Asia. Genetically diverse, this species is divided into six subspecies but genetic traits governing this classification are poorly understood. RESULTS SkIf (Specific k-mers Identification) was designed and exploited for comparative genomics on a dataset of 46 X. fastidiosa genomes, including seven newly sequenced individuals. It was helpful to quickly check the synonymy between strains from different collections. SkIf identified specific SNPs within 16S rRNA sequences that can be employed for predicting the distribution of Xylella through data mining. Applied to inter- and intra-subspecies analyses, it identified specific k-mers in genes affiliated to differential gene ontologies. Chemotaxis-related genes more prevalently possess specific k-mers in genomes from subspecies fastidiosa, morus and sandyi taken as a whole group. In the subspecies pauca increased abundance of specific k-mers was found in genes associated with the bacterial cell wall/envelope/plasma membrane. Most often, the k-mer specificity occurred in core genes with non-synonymous SNPs in their sequences in genomes of the other subspecies, suggesting putative impact in the protein functions. The presence of two integrative and conjugative elements (ICEs) was identified, one chromosomic and an entire plasmid in a single strain of X. fastidiosa subsp. pauca. Finally, a revised taxonomy of X. fastidiosa into three major clades defined by the subspecies pauca (clade I), multiplex (clade II) and the combination of fastidiosa, morus and sandyi (clade III) was strongly supported by k-mers specifically associated with these subspecies. CONCLUSIONS SkIf is a robust and rapid software, freely available, that can be dedicated to the comparison of sequence datasets and is applicable to any field of research. Applied to X. fastidiosa, an emerging pathogen in Europe, it provided an important resource to mine for identifying genetic markers of subspecies to optimize the strategies attempted to limit the pathogen dissemination in novel areas.
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Affiliation(s)
- Nicolas Denancé
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071, Beaucouzé cedex, France
| | - Martial Briand
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071, Beaucouzé cedex, France
| | - Romain Gaborieau
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071, Beaucouzé cedex, France
| | - Sylvain Gaillard
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071, Beaucouzé cedex, France
| | - Marie-Agnès Jacques
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071, Beaucouzé cedex, France.
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Bansal K, Kumar S, Patil PB. Complete Genome Sequence Reveals Evolutionary Dynamics of an Emerging and Variant Pathovar of Xanthomonas euvesicatoria. Genome Biol Evol 2018; 10:3104-3109. [PMID: 30346514 PMCID: PMC6257573 DOI: 10.1093/gbe/evy238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2018] [Indexed: 11/13/2022] Open
Abstract
Xanthomonas, a complex group of pathogens, infects more than 400 plants, which is expanding to new hosts causing serious diseases. Genome-based studies are transforming our understanding on diversity and relationship of host-specific members, known as pathovars. In this study, we report complete genome sequence of a novel pathovar Xanthomonas axonopodis pv. commiphorae (Xcom) from India. It causes gumming disease of Commiphora wightii, a medicinally important plant. Genome-based phylogenetic and taxonomic investigation revealed that the pathovar belongs to Xanthomonas euvesicatoria and not X. axonopodis as reported earlier. Interestingly, it is a novel host and novel geographic origin for a X. euvesicatoria pathovar. A core-genome-based phylogenetic analysis resolved the pathovar complex of this species on the basis of their hosts. Interestingly, this pathovar harbors a unique 35-kb plasmid encoding type III effectors and toxin-antitoxin gene that is absent in other X. euvesicatoria pathovars and infects tomato, pepper, rose, onion, philodendron, alfalfa, and citrus plants. The pathovar contains two TAL (transcription activator-like) genes, one on plasmid and another on genomic region with an additional pseudo TAL gene flanked by IS elements in the plasmid. Further, Xcom has acquired a novel set of lipopolysaccharide biosynthesis genes after its divergence from the closely related pathovar that infects rose and supports the role of horizontal gene transfer in hypervariation at this locus in the species. Complete genome sequence of this variant pathovar has provided novel insights into evolution of an emerging pathovar in Xanthomonas and will be valuable resource in pathogenomics of X. euvesicatoria.
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Affiliation(s)
- Kanika Bansal
- Bacterial Genomics and Evolution Laboratory, CSIR—Institute of Microbial Technology, Chandigarh, India
| | - Sanjeet Kumar
- Department of Archaeogenetics, Max Planck Institute for the Science of Human History, Jena, Germany
| | - Prabhu B Patil
- Bacterial Genomics and Evolution Laboratory, CSIR—Institute of Microbial Technology, Chandigarh, India
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Larrea-Sarmiento A, Dhakal U, Boluk G, Fatdal L, Alvarez A, Strayer-Scherer A, Paret M, Jones J, Jenkins D, Arif M. Development of a genome-informed loop-mediated isothermal amplification assay for rapid and specific detection of Xanthomonas euvesicatoria. Sci Rep 2018; 8:14298. [PMID: 30250161 PMCID: PMC6155141 DOI: 10.1038/s41598-018-32295-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 09/03/2018] [Indexed: 02/06/2023] Open
Abstract
Bacterial spot (BS), caused by Xanthomonas euvesicatoria, X. vesicatoria, X. gardneri and X. perforans, is an economically important bacterial disease of tomato and pepper. Symptoms produced by all four species are nearly indistinguishable. At present, no point-of-care diagnostics exist for BS. In this research, we examined genomes of X. euvesicatoria, X. vesicatoria, X. gardneri, X. perforans and other species of Xanthomonas; the unique gene recG was chosen to design primers to develop a loop-mediated isothermal amplification (LAMP) assay to rapidly and accurately identify and differentiate X. euvesicatoria from other BS causing Xanthomonas sp. using a field-deployable portable BioRangerTM instrument. Specificity of the developed assay was tested against 39 strains of X. euvesicatoria and 41 strains of other species in inclusivity and exclusivity panels, respectively. The assay detection limit was 100 fg (~18 genome copies) of genomic DNA and 1,000 fg in samples spiked with tomato DNA. The assay unambiguously detected X. euvesicatoria in infected tomato plant samples. Concordant results were obtained when multiple operators performed the test independently. No false positives and false negatives were detected. The developed LAMP assay has numerous applications in diagnostics, biosecurity and disease management.
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Affiliation(s)
- Adriana Larrea-Sarmiento
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, United States
| | - Upasana Dhakal
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, United States
| | - Gamze Boluk
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, United States
| | - Lilly Fatdal
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, United States
| | - Anne Alvarez
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, United States
| | - Amanda Strayer-Scherer
- Department of Entomology and Plant Pathology, Mountain Research Station, North Carolina State University, Waynesville, NC, United States
| | - Mathews Paret
- Department of Plant Pathology, North Florida Research and Education Center, University of Florida, Quincy, FL, United States
| | - Jeff Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | - Daniel Jenkins
- Department of Molecular Biosciences and BioEngineering, University of Hawaii at Manoa, Honolulu, HI, United States
| | - Mohammad Arif
- Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, United States.
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12
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Almeida E, Serra CR, Albuquerque P, Guerreiro I, Teles AO, Enes P, Tavares F. Multiplex PCR identification and culture-independent quantification of Bacillus licheniformis by qPCR using specific DNA markers. Food Microbiol 2018; 74:1-10. [PMID: 29706322 DOI: 10.1016/j.fm.2018.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 12/29/2017] [Accepted: 02/17/2018] [Indexed: 11/26/2022]
Abstract
Probiotics benefits in fish farming have been usually inferred appraising the effects observed on the host and not through the direct assessment of probiotic dynamics in the host gut microbiota. To overcome this gap, quantitative PCR (qPCR) can be a powerful approach to study the bacterial dynamics in fish gut microbiota. The presented work proposes four B. licheniformis-specific DNA markers and details a qPCR method to track putative probiotics B. licheniformis on fish gut. The four B. licheniformis-specific DNA markers - BL5B (hypothetical protein BL00303), BL8A (serA2), BL13C (rfaB) and BL18A (ligD) - were selected and validated by PCR and multiplex-PCR with 20 B. licheniformis isolates and a broad range of non-target bacteria. To assess the dynamics of B. licheniformis in the digesta of farmed fish, a qPCR was validated using markers BL8A and BL18A and calibration curves obtained for both markers with digesta samples spiked with B. licheniformis cells showed a high correlation (R2 > 0.99) over 6 log units (CFU/reaction), and a limit of detection (LOD) as low as 247 CFUs/reaction. Furthermore, the consistent qPCR repeatability and reproducibility underline the specificity and reliability of the qPCR proposed. Ultimately, the possibility to monitor the dynamics of B. licheniformis probiotics in the gut microbiota of farmed fish might be instrumental to optimize best practices in aquaculture.
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Affiliation(s)
- Eduarda Almeida
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal; FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal
| | - Cláudia R Serra
- CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Pedro Albuquerque
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
| | - Inês Guerreiro
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Aires Oliva Teles
- FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Paula Enes
- CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal
| | - Fernando Tavares
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Campus Agrário de Vairão, 4485-661 Vairão, Portugal; FCUP - Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Edifício FC4 - Via Panorâmica nº 36, 4150-564 Porto, Portugal.
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13
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Fernandes C, Albuquerque P, Sousa R, Cruz L, Tavares F. Multiple DNA Markers for Identification of Xanthomonas arboricola pv. juglandis Isolates and its Direct Detection in Plant Samples. PLANT DISEASE 2017; 101:858-865. [PMID: 30682925 DOI: 10.1094/pdis-10-16-1481-re] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Xanthomonas arboricola pv. juglandis (Xaj) is the etiological agent of walnut (Juglans regia L.) bacterial blight (WBB), and has been associated to other walnut emerging diseases, namely brown apical necrosis (BAN) and vertical oozing canker (VOC), altogether severely affecting the walnut production worldwide. Despite the research efforts carried out to disclose Xaj genetic diversity, reliable molecular methods for rapid identification of Xaj isolates and culture-independent detection of Xaj in infected plant samples are still missing. In this work, we propose nine novel specific DNA markers (XAJ1 to XAJ9) selected by dedicated in silico approaches to identify Xaj isolates and detect these bacteria in infected plant material. To confirm the efficacy and specificity of these markers, dot blot hybridization was carried out across a large set of xanthomonads. This analysis, which confirmed the pathovar specificity of these markers, allowed to identify four broad-range markers (XAJ1, XAJ4, XAJ6, and XAJ8) and five narrow-range markers (XAJ2, XAJ3, XAJ5, XAJ7, and XAJ9), originating 12 hybridization patterns (HP1 to HP12). No evident relatedness was observed between these hybridization patterns and the geographic origin from which the isolates were obtained. Interestingly, four isolates that clustered together according the gyrB phylogenetic analysis (CPBF 1507, 1508, 1514, and 1522) presented the same hybridization pattern (HP11), suggesting that these nine markers might be informative to rapidly discriminate and identify different Xaj lineages. Taking into account that a culture-independent detection of Xaj in plant material has never been described, a multiplex PCR was optimized using markers XAJ1, XAJ6, and XAJ8. This triplex PCR, besides confirming the dot blot data for each of the 52 Xaj, was able to detect Xaj in field infected walnut leaves and fruits. Altogether, these nine Xaj-specific markers allow conciliating the specificity of DNA-detection assays with typing resolution, contributing to rapid detection and identification of potential emergent and acutely virulent Xaj genotypes, infer their distribution, disclose the presence of this phytopathogen on potential alternative host species and improve phytosanitary control.
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Affiliation(s)
- Camila Fernandes
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal; INIAV - Instituto Nacional de Investigação Agrária e Veterinária, Av. da República, Quinta do Marquês, Oeiras, Portugal; and FCUP - Faculdade de Ciências, Departamento de Biologia, Rua do Campo Alegre S/n° Universidade do Porto, Porto, Portugal
| | - Pedro Albuquerque
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal
| | - Rui Sousa
- INIAV - Instituto Nacional de Investigação Agrária e Veterinária, Polo de Alcobaça, Estrada de Leiria, Alcobaça, Portugal
| | - Leonor Cruz
- INIAV - Instituto Nacional de Investigação Agrária e Veterinária, Av. da República, Quinta do Marquês, Oeiras, Portugal; and BioISI - Instituto de Biossistemas e Ciências Integrativas, Campus da FCUL, Campo Grande, Lisboa, Portugal
| | - Fernando Tavares
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal; and FCUP - Faculdade de Ciências, Departamento de Biologia, Rua do Campo Alegre S/n° Universidade do Porto, Porto, Portugal
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14
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Muñoz Bodnar A, Cruz Gómez LM, Bernal A, Szurek B, López Carrascal CE. COMPARING INOCULATION METHODS TO EVALUATE THE GROWTH OF Xanthomonas axonopodis pv. manihotis ON CASSAVA PLANTS. ACTA BIOLÓGICA COLOMBIANA 2014. [DOI: 10.15446/abc.v20n2.43130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
<p class="ecxmsonormal"><em>Xanthomonas axonopodis </em>pv. manihotis (<em>Xam</em>) is the causal agent of cassava bacterial blight (CBB), a major disease for cassava crops in South America and Africa. Until now the development of the disease is measured via AUDPC (Area Under Disease Progress Curve) but no reliable quantitative methods are available probably due to high variability of bacterial growth <em>in planta</em>. To establish an accurate method for bacterial quantification during the course of <em>Xam</em> infection within the host tissues, we analyzed bacterial populations upon stem and leaf-puncturing as well as leaf-clipping of cassava varieties MCOL1522 and SG107-35 challenged with the virulent <em>Xam</em> strain CIO151. Here, we show that the movement of bacteria along the tissues and especially in leaves is stochastic. 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<w:LsdException Locked="false" Priority="39" QFormat="true" Name="TOC Heading"/> </w:LatentStyles> </xml><![endif]--><!--[if !supportAnnotations]--><!--[endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} </style> <![endif]--></p><p class="EstiloActa" style="text-align: justify;"><em style="mso-bidi-font-style: normal;"><span lang="X-NONE">Xanthomonas axonopodis </span></em><span lang="X-NONE">pv. manihotis<em style="mso-bidi-font-style: normal;"> (Xam)</em> es el agente causal del tizón bacteriano de la yuca, una de las principales enfermedades de los cultivos de yuca en América del Sur y África. Hasta ahora, el desarrollo de la enfermedad se mide a través de AUDPC <em style="mso-bidi-font-style: normal;">(Area<span style="mso-spacerun: yes;"> </span>Under Disease Progress curve)</em>, pero no hay disponibles métodos cuantitativos fiables,<span style="mso-spacerun: yes;"> </span>esto debido posiblemente a la alta variabilidad del crecimiento bacteriano en la planta. Para establecer un método exacto para la cuantificación bacteriana durante el curso de la infección <em style="mso-bidi-font-style: normal;">Xam </em>dentro de los tejidos del huésped, se analizaron las poblaciones de bacterias sobre tallo y hojas, así como corte de hojas de las <a style="mso-comment-reference: as_1; mso-comment-date: 20141102T2035;">variedades de yuca</a></span><span lang="X-NONE">MCOL1522 y SG107-35 con la cepa virulenta CIO151 <em style="mso-bidi-font-style: normal;">Xam.</em> <a style="mso-comment-reference: as_2; mso-comment-date: 20141102T2035;">En esta investigación se </a></span><span lang="X-NONE">muestra que el movimiento de las bacterias a lo largo de los tejidos y especialmente en las hojas es estocástico. Por otra parte, hemos podido demostrar el crecimiento diferencial de la cepa virulenta<span style="mso-spacerun: yes;"> </span><em style="mso-bidi-font-style: normal;">Xam</em> CIO151 tras la punción al tallo y la cuantificación de la bacteria a 6 cm de distancia del punto de inoculación de dos variedades que presentan niveles contrastantes de susceptibilidad.</span></p><p class="ecxmsonormal"> </p>
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Almeida A, Albuquerque P, Araujo R, Ribeiro N, Tavares F. Detection and discrimination of common bovine mastitis-causing streptococci. Vet Microbiol 2013; 164:370-7. [PMID: 23578710 DOI: 10.1016/j.vetmic.2013.03.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 03/01/2013] [Accepted: 03/02/2013] [Indexed: 11/19/2022]
Abstract
Detection and typing of bovine mastitis pathogens are currently limited by time-consuming and culture-based techniques. In this work, a novel genus-specific DNA marker for Streptococcus and species-specific DNA markers for the prevalent mastitis pathogens Streptococcus agalactiae and Streptococcus uberis were designed and assessed. In order to enable further discrimination of these mastitis-causing streptococci, metabolic and pathogenicity-related genes were used to infer additional functional markers. A total of 12 DNA markers were validated with a set of 50 reference strains and isolates, representative of the Streptococcus genus, of closely related species and of microorganisms with matching habitats. The experimental validation, using dot blot hybridization under high stringency conditions, confirmed the specificity of the selected markers. The broad-spectrum taxonomic marker (ST1) was specific to the Streptococcus genus and the markers selected for S. agalactiae (A1 and A2) and S. uberis (U1 and U2) were shown to be species-specific. The functional markers revealed strain-specific patterns of S. agalactiae and S. uberis. Markers derived from the fructose operon (FO1 and FO3) were specific to bovine isolates of S. agalactiae, and the nisin operon markers (NU1 and NU3) were able to discriminate isolates belonging to S. agalactiae and S. uberis. The virulence-associated markers (V1, V2 and V3) allowed the detection of S. uberis and of closely related species. This work suggests that the combined use of these novel taxa-specific markers coupled with discriminatory functional markers presents a promising approach for the rapid and cost-effective detection and discrimination of common bovine mastitis-causing pathogens, which will contribute to an improved treatment and control of this disease.
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Affiliation(s)
- Alexandre Almeida
- FCUP - Faculdade de Ciências, Departamento de Biologia, Edifício FC4, Via Panorâmica n° 36, Universidade do Porto, 4150-564 Porto, Portugal
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