40 results on '"Heungens, Kurt"'
Search Results
2. Strain-specific and sensitive monitoring of the biocontrol agent Trichoderma asperellum T34 in growing medium via real-time PCR.
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Van Poucke, Kris, França, Soraya C., Haegeman, Annelies, Casanova, Eva, and Heungens, Kurt
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BIOLOGICAL pest control agents ,TRICHODERMA ,NON-target organisms ,INTERNAL auditing ,RHIZOCTONIA ,RHIZOBACTERIA ,POLYMERASE chain reaction - Abstract
Trichoderma asperellum Samuels, Lieckf. & Nirenberg is one of several Trichoderma species comprising effective biocontrol strains. One of these, Trichoderma asperellum T34, shows activity against soilborne pathogens such as Rhizoctonia, Fusarium, and Pythium. The activity of biocontrol strains such as T34 depends on their establishment in the rhizosphere. Monitoring of the population of T34 and other strains in the rhizosphere and the growing medium is therefore important for evaluating their potential in different crops and different growing systems. Until now, strain-specific monitoring has been very difficult as the main quantification methods, i.e. traditional dilution plating or standard molecular detection methods, are specific only at genus or species level, respectively. Genotyping-by-sequencing was used to identify genomic loci specific to T34. These were used to develop strain-specific Taqman real-time (qPCR) assays. After testing for specificity and sensitivity, two assays were combined in duplex format. The duplicate assay provided an internal control to avoid a false positive signal in case one of the target loci would be present in an as yet unidentified non-target organism. An optional enrichment step in semi-selective medium was included for increased sensitivity in cases of small T34 population size, theoretically allowing detection down to 0.1 spore equivalent per mL growing medium. The techniques were applied to 200 mL samples of growing medium analyzed 0, 19, and 112 days after spiking with different numbers and combinations of spores from target and non-target Trichoderma isolates. This technique shows potential for developing other strain-specific detection assays using an affordable genotyping tool. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Phylogeography, origin and population structure of the self‐fertile emerging plant pathogen Phytophthora pseudosyringae.
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Mullett, Martin S., Harris, Anna R., Scanu, Bruno, Van Poucke, Kris, LeBoldus, Jared, Stamm, Elizabeth, Bourret, Tyler B., Christova, Petya K., Oliva, Jonás, Redondo, Miguel A., Talgø, Venche, Corcobado, Tamara, Milenković, Ivan, Jung, Marília Horta, Webber, Joan, Heungens, Kurt, and Jung, Thomas
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PHYTOPATHOGENIC microorganisms ,PHYTOPHTHORA ,OOMYCETES ,LIFE history theory ,PHYLOGEOGRAPHY ,GENE flow - Abstract
Phytophthora pseudosyringae is a self‐fertile pathogen of woody plants, particularly associated with tree species from the genera Fagus, Notholithocarpus, Nothofagus and Quercus, which is found across Europe and in parts of North America and Chile. It can behave as a soil pathogen infecting roots and the stem collar region, as well as an aerial pathogen infecting leaves, twigs and stem barks, causing particular damage in the United Kingdom and western North America. The population structure, migration and potential outcrossing of a worldwide collection of isolates were investigated using genotyping‐by‐sequencing. Coalescent‐based migration analysis revealed that the North American population originated from Europe. Historical gene flow has occurred between the continents in both directions to some extent, yet contemporary migration is overwhelmingly from Europe to North America. Two broad population clusters dominate the global population of the pathogen, with a subgroup derived from one of the main clusters found only in western North America. Index of association and network analyses indicate an influential level of outcrossing has occurred in this preferentially inbreeding, homothallic oomycete. Outcrossing between the two main population clusters has created distinct subgroups of admixed individuals that are, however, less common than the main population clusters. Differences in life history traits between the two main population clusters should be further investigated together with virulence and host range tests to evaluate the risk each population poses to natural environments worldwide. [ABSTRACT FROM AUTHOR]
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- 2024
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4. In-field detection of Alternaria solani in potato crops using hyperspectral imaging
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Van De Vijver, Ruben, Mertens, Koen, Heungens, Kurt, Somers, Ben, Nuyttens, David, Borra-Serrano, Irene, Lootens, Peter, Roldán-Ruiz, Isabel, Vangeyte, Jürgen, and Saeys, Wouter
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- 2020
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5. Unravelling hybridization in Phytophthora using phylogenomics and genome size estimation
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Van Poucke, Kris, Haegeman, Annelies, Goedefroit, Thomas, Focquet, Fran, Leus, Leen, Jung, Marília Horta, Nave, Corina, Redondo, Miguel Angel, Husson, Claude, Kostov, Kaloyan, Lyubenova, Aneta, Christova, Petya, Chandelier, Anne, Slavov, Slavcho, de Cock, Arthur, Bonants, Peter, Werres, Sabine, Palau, Jonàs Oliva, Marçais, Benoit, Jung, Thomas, Stenlid, Jan, Ruttink, Tom, and Heungens, Kurt
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- 2021
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6. Venturia inaequalis trapped: molecular quantification of airborne inoculum using volumetric and rotating arm samplers
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Torfs, Sanne, Van Poucke, Kris, Van Campenhout, Jelle, Ceustermans, An, Croes, Sarah, Bylemans, Dany, Van Hemelrijck, Wendy, Keulemans, Wannes, and Heungens, Kurt
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- 2019
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7. Detection of Fusarium oxysporum f.sp. lactucae race 1 and 4 via race-specific real-time PCR and target enrichment.
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Mestdagh, Hanna, Van Poucke, Kris, Haegeman, Annelies, Dockx, Tinne, Vandevelde, Isabel, Dendauw, Ellen, Decombel, An, Höfte, Monica, and Heungens, Kurt
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FUSARIUM oxysporum ,RACE ,PLANT cells & tissues ,POLYMERASE chain reaction ,EPIDEMIOLOGICAL research ,HARVESTING ,VASCULAR diseases - Abstract
Fusarium oxysporum f.sp. lactucae (Fol) causes a vascular disease in lettuce that results in significant yield losses. Race-specific and sensitive real-time PCR assays were developed for Fol races 1 and 4, which are prevalent in Europe. Using genotyping-by-sequencing, unique DNA loci specific to each race were identified and subsequently used for the design of primers and hydrolysis probes. Two assays per race were developed to ensure specificity. The two assays of each race could be run in duplex format, while still giving a sensitivity of 100 fg genomic DNA for all assays. Sample preparation methods were developed for plant tissue, soil, and surfaces, with an extra enrichment step when additional sensitivity was required. By controlling the incubation conditions during the enrichment step, the real-time PCR signal could be matched to the number of spore equivalents in the original sample. When enriching naturally infested soil, down to six conidiospore equivalents L
-1 soil could be detected. As enrichment ensures sensitive detection and focuses on living Fol propagules, it facilitates the evaluation of control measures. The developed detection methods for soil and surfaces were applied to samples from commercial lettuce farms and confirmed the prevalence of Fol race 4 in Belgium. Monitoring of soil disinfestation events revealed that despite a dramatic decrease in quantity, the pathogen could still be detected either immediately after sheet steaming or after harvesting the first new crop. The detection method for plant tissue was successfully used to quantify Fol in lettuce inoculated with race 1, race 4 or a combination of both. Under the temperature conditions used, race 4 was more aggressive than race 1, as reflected in larger amounts of DNA of race 4 detected in the roots. These newly developed assays are a promising tool for epidemiological research as well as for the evaluation of control measures. [ABSTRACT FROM AUTHOR]- Published
- 2023
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8. Euphresco Sendo: An international laboratory comparison study of molecular tests for Synchytrium endobioticum detection and identification
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van de Vossenberg, Bart, Westenberg, Marcel, Adams, Ian, Afanasenko, Olga, Besheva, Ani, Boerma, Margriet, Choiseul, James, Dekker, Toos, Flath, Kerstin, van Gent-Pelzer, Marga, Heungens, Kurt, Karelov, Anatolii, Kibildiene, Ilona, Przetakiewicz, Jaroslaw, Schlenzig, Alexandra, Yakovleva, Vera, and van Leeuwen, Gerard
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- 2018
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9. Fusarium isolates from Belgium causing wilt in lettuce show genetic and pathogenic diversity.
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Claerbout, Jolien, Van Poucke, Kris, Mestdagh, Hanna, Delaere, Ilse, Vandevelde, Isabel, Venneman, Sofie, Decombel, An, Bleyaert, Peter, Neukermans, Jenny, Viaene, Nicole, Heungens, Kurt, and Höfte, Monica
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FUSARIUM oxysporum ,GENETIC variation ,LETTUCE ,FUSARIUM ,NATURAL immunity ,GREENHOUSE plants - Abstract
Fusarium oxysporum f. sp. lactucae race 4 causes vascular necrosis and wilting of lettuce. First observed in Belgium in 2015, the lack of disease resistance in commercial cultivars allowed this pathogen to spread to nearly the entire Belgian production area within 4 years. Different levels of disease development were observed in different commercial greenhouses. To help explain this variation, we collected 78 Fusarium isolates and characterized them both physiologically and genetically. Molecular race identification indicated that 91% of the isolates belonged to race 4, while 6% of the isolates belonged to race 1, which was not previously reported in Belgium. Pathogenicity assays using differential cultivars confirmed the molecular race assignment of selected isolates. Cultivar Patriot was identified as a suitable new differential cultivar to race 4. Race 4 isolates were more aggressive than race 1 isolates at 24°C, but only when using chlamydospore inoculum instead of a root dip assay containing microconidia. Variation in pathogenicity and aggressiveness of the races may explain differences in disease development in commercial greenhouses. Based on genotyping‐by‐sequencing (GBS), race 1 and race 4 isolates were highly similar to reference isolates. Fusarium curvatum, F. oxysporum f. sp. tulipae and F. oxysporum f. sp. rhois were phylogenetically separated from F. oxysporum f. sp. lactucae races 1 and 4 based on the GBS data, but not when using multilocus sequence data. Within F. oxysporum f. sp. lactucae race 4, the GBS data differentiated two rather homogeneous groups, suggesting at least two introductions. However, the two groups did not differ in aggressiveness. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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10. (2085) Proposal to conserve the name Cylindrocladium buxicola against C. pseudonaviculatum (Ascomycota)
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Henricot, Béatrice, David, John, Ivors, Kelly, Heungens, Kurt, Spooner, Brian, Sierra, Ana Pérez, and Daughtrey, Margery L.
- Published
- 2012
11. Emergence of the sudden oak death pathogen Phytophthora ramorum
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Grünwald, Niklaus J., Garbelotto, Matteo, Goss, Erica M., Heungens, Kurt, and Prospero, Simone
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- 2012
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12. Identification of new polymorphic microsatellite markers in the NA1 and NA2 lineages of Phytophthora ramorum
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Vercauteren, Annelies, Larsen, Meg, Goss, Erica, Grünwald, Niklaus J., Maes, Martine, and Heungens, Kurt
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- 2011
13. Interlaboratory Performance of a Real-Time PCR Method for Detection of Ceratocystis platani , the Agent of Canker Stain of Platanus spp.
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Brunetti, Angela, Heungens, Kurt, Hubert, Jacqueline, Ioos, Renaud, Bianchi, Gian Luca, De Amicis, Francesca, Chandelier, Anne, Van Der Linde, Sietse, Perez-Sierra, Ana, Gualandri, Valeria, Silletti, Maria Rosaria, Trisciuzzi, Vito Nicola, Rimondi, Silvia, Baschieri, Tiziana, Romano, Elio, Lumia, Valentina, Luigi, Marta, Faggioli, Francesco, and Pilotti, Massimo
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SYCAMORES , *WOOD , *DETECTION limit , *VASCULAR diseases , *TESTING laboratories , *LABORATORIES , *PERFORMANCE theory - Abstract
Ceratocystis platani (CP), an ascomycetous fungus, is the agent of canker stain, a lethal vascular disease of Platanus species. Ceratocystis platani has been listed as a quarantine pest (EPPO A2 list) due to extensive damage caused in Southern Europe and the Mediterranean region. As traditional diagnostic assays are ineffective, a Real-Time PCR detection method based on EvaGreen, SYBR Green, and Taqman assays was previously developed, validated in-house, and included in the official EPPO standard PM7/14 (2). Here, we describe the results of a test performance study performed by nine European laboratories for the purpose of an interlaboratory validation. Verification of the DNA extracted from biological samples guaranteed the high quality of preparations, and the stability and the homogeneity of the aliquots intended for the laboratories. All of the laboratories reproduced nearly identical standard curves with efficiencies close to 100%. Testing of blind-coded DNA extracted from wood samples revealed that all performance parameters—diagnostic sensitivity, diagnostic specificity, accuracy and reproducibility—were best fit in most cases both at the laboratory and at the assay level. The previously established limit of detection, 3 fg per PCR reaction, was also validated with similar excellent results. The high interlaboratory performance of this Real-Time PCR method confirms its value as a primary tool to safeguard C. platani-free countries by way of an accurate monitoring, and to investigate the resistance level of potentially canker stain-resistant Platanus genotypes. [ABSTRACT FROM AUTHOR]
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- 2022
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14. Real-time PCR mediated monitoring of Fusarium foetens in symptomatic and non-symptomatic hosts
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Huvenne, Hanneke, Debode, Jane, Maes, Martine, and Heungens, Kurt
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- 2011
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15. Identification and characterization of pathotypes in Puccinia horiana, a rust pathogen of Chrysanthemum x morifolium
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De Backer, Mathias, Alaei, Hossein, Van Bockstaele, Erik, Roldan-Ruiz, Isabel, van der Lee, Theo, Maes, Martine, and Heungens, Kurt
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- 2011
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16. Genotypic and phenotypic characterization of the European A2 isolates of Phytophthora ramorum
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Vercauteren, Annelies, De Dobbelaere, Isabelle, Van Bockstaele, Erik, Maes, Martine, and Heungens, Kurt
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- 2011
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17. Identification and early detection of Cryphonectria parasitica and Ceratocystis platani occurring on trees in Europe (CERACRY)
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van Leeuwen, Gerard, Heungens, Kurt, Chandelier, Anne, Svobodová, Iveta, Tomankova, Katerina, Csertan-Halasz, Agnes, Destefanis, Maria, Pilotti, Massimo, Braganca, Helena, Perez-Sierra, Ana, Vettraino, Anna Maria, Parker, John, and Prospero, Simone
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fungi ,Euphresco, plant health, Ceratocystis platani, Cryphonectria parasitica, mycology, survey, collections, diagnostics, TPS - Abstract
The overall goal of the project was to bring together scientists, practitioners and official national bodies (NPPOs) to share knowledge on two important quarantine diseases of trees in Europe: Ceratocystis platani and Cryphonectria parasitica. The threats posed by Ceratocystis platani are often underestimated and even in countries where the disease already occurs, not much measures are taken to limit the spread of this devastating disease. The project contributed to: Improve knowledge on the distribution of Cryphonectria parasitica in European countries. It was shown that C. parasitica is present in Belgium and United Kingdom, but not in Ireland. In the Netherlands, the fungus was found several times on imported Castanea stakes/fences in 2018, but not in nurseries or public green. Develop a collection of C. parasitica isolates. The isolates were used to determine the population structure of C. parasitica in Europe. Evidence was found that in countries where the pathogen was relatively recently described (e.g. UK), the pathogen was introduced several times but has not spread widely, possibly due to suboptimal climatic conditions. Organise a test performance study (TPS) for the real-time PCR test from Pilotti et al. (2012) for the detection of C. platani in wood. Specifically, EvaGreen, SYBR Green and Taqman tests were validated. Standard curves confirmed that the tests have high amplification efficiency. For analytical sensitivity, all laboratories detected 15 and 3 fg C. platani gDNA, thus reproducing the previously reported detection threshold of the method. Testing blind samples yielded a 100% scoring sensitivity, accuracy and specificity in all the experiments, with an exception in the SYBR Green test for which results from one laboratory were nonconforming for the criterion of accuracy.
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- 2019
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18. Diagnostic methods for Synchytrium endobioticum, especially for pathotype identification (SENDO)
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van Leeuwen, Gerard, van de Vossenberg, Bart, Flath, Kerstin, Przetakiewicz, Jaroslaw, Boerma, Margriet, Heungens, Kurt, Dimitrova, Lidia, Besheva, Ani, Beniusis, Arunas, Adams, Ian, Afanaseko, Olga, Yakovleva, Vera, Schlenzig, Alexandra, Choiseul, James, and Bonants, Peter
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Euphresco, plant health, diagnostics, TPS, Synchytrium endobioticum, pathotypes, potato - Abstract
The main parts of the project consisted of testing new differential cultivars for pathotype identification (bioassays), and the generation of validation data for three molecular S. endobioticum detection and identification assays. As a bioassay, the partners in the project agreed upon the use of the Glynne-Lemmerzahl method to identify pathotypes. In the second year of the project (2013) a test performance study (TPS) was organised. Two different pathotypes were tested, pathotype 6(O1) and 18(T1), and five partners joined in. The cultivars Talent and Logo were chosen to replace cv Miriam in the actual set of differential cultivars (EPPO, 2004). In former research, cv Miriam proved to be less suitable for separating pathotypes 6(O1) and 18(T1), results were inconsistent. As a result, we concluded that cv Talent was the best replacement of cv Miriam in the actual set of differential cultivars. Also, the cultivar Gawin can be added to the set of differentials in a new version of the EPPO Diagnostic Protocol on Synchytrium endobioticum. An international test performance study was organised to generate validation data for three molecular S. endobioticum detection and identification assays: Boogert et al. (2005), van GentPelzer et al. (2010), and Bonants et al. (2015). Two TPS rounds were organised focussing on different test matrices: round 1: wart material, and round 2: winter spore suspensions. When using the assays for detection and identification of S. endobioticum in warted potato tissue, no significant differences were observed for diagnostic sensitivity, diagnostic specificity, overall accuracy, analytical sensitivity and robustness. After applying a Ct cut-off value for the GentPelzer assay, all assays are regarded equal. When using the assays for detection and identification of S. endobioticum in winter spore suspensions, the Boogert and Gent-Pelzer assays significantly outperform the Bonants assay for diagnostic sensitivity and diagnostic specificity. For overall accuracy and analytical sensitivity, the Gent-Pelzer assay significantly outperforms the Boogert and Bonants assays and is regarded as the assay of choice when identifying S. endobioticum winter spores. The tests included in this TPS are regarded fit for purpose for routine testing of wart material and winter spore suspensions with ≥ 500 spores per sample., Report of the Euphresco project 'Diagnostic methods for Synchytrium endobioticum, especially for pathotype identification (SENDO)'
- Published
- 2019
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19. Identification of Xenorhabdus nematophila genes required for mutualistic colonization of Steinernema carpocapsae nematodes
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Heungens, Kurt, Cowles, Charles E., and Goodrich-Blair, Heidi
- Published
- 2002
20. Six new Phytophthora species from ITS Clade 7a including two sexually functional heterothallic hybrid species detected in natural ecosystems in Taiwan
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Jung, Thomas, Jung, Marília Horta, Scanu, Bruno, Seress, Diána, Kovács, Gábor M., Maia, Cristiana, Pérez-Sierra, Ana M., Chang, Tuntschu, Chandelier, Anne, Heungens, Kurt, Van Poucke, Kris, Abad Campos, Paloma, León, Maela C., Cacciola, Santa Olga, and Bakonyi, József
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AGR/12 Patologia vegetale - Abstract
During a survey of Phytophthora diversity in natural ecosystems in Taiwan six new species were detected. Multigene phylogeny based on the nuclear ITS, ß-tubulin and HSP90 and the mitochondrial cox1 and NADH1 gene sequences demonstrated that they belong to ITS Clade 7a with P. europaea, P. uniformis, P. rubi and P. cambivora being their closest relatives. All six new species differed from each other and from related species by a unique combination of morphological characters, the breeding system, cardinal temperatures and growth rates. Four homothallic species, P. attenuate, P. flexuosa, P. formosa and P. intricata, were isolated from rhizosphere soil of healthy forests of Fagus hayatae, Quercus glandulifera, Q. tarokoensis, Castanopsis carlesii, Chamaecyparis formosensis and Araucaria cunninghamii. Two heterothallic species, P. xheterohybrida and P. xincrassata, were exclusively detected in three forest streams. All P. xincrassata isolates belonged to the A2 mating type while isolates of P. xheterohybrida represented both mating types with oospore abortion rates according to Mendelian ratios (4–33 %). Multiple heterozygous positions in their ITS, ß-tubulin and HSP90 gene sequences indicate that P. xheterohybrida, P. xincrassata and P. cambivora are interspecific hybrids. Consequently, P. cambivora is re-described as P. xcambivora without nomenclatural act. Pathogenicity trials on seedlings of Castanea sativa, Fagus sylvatica and Q. suber indicate that all six new species might pose a potential threat to European forests.
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- 2017
21. Early colonization events in the mutualistic association between Steinernema carpocapsae nematodes and Xenorhabdus nematophila bacteria
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Martens, Eric C., Heungens, Kurt, and Goodrich-Blair, Heidi
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Host-bacteria relationships -- Physiological aspects ,Nematoda -- Physiological aspects ,Roundworm ,Bacteria -- Physiological aspects ,Microbial metabolism -- Physiological aspects ,Biological sciences - Abstract
Monitoring of nematodes throughout their reproductive cycle, using an in vitro culturing technique, reveals that the infective juvenile colonization is initiated by the Xenorhabdus nematophila bacteria by competing for colonization sites within the Steinernema carpocapsae nematode intestine. Data indicate that the final population of bacteria in the nematode is monoclonal originating from one or two bacterial clones.
- Published
- 2003
22. Breeding and selection of Buxus for resistance to Calonectria pseudonaviculata.
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Van Laere, Katrijn, Heungens, Kurt, Gehesquière, Bjorn, Leus, Leen, Hermans, Didier, and Van Huylenbroeck, Johan
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BOXWOOD , *BLIGHT diseases (Botany) , *DISEASE resistance of plants , *SYMPTOMS , *VACCINATION , *GENOTYPES - Abstract
Box blight is a widespread disease of Buxus caused by the pathogen Calonectria pseudonaviculata. It is responsible for significant losses in nurseries, gardens and wild boxwood populations. Our goal was to maximize the efficiency of a breeding programme towards increased disease resistance. The use of artificial inoculation of young F1 seedlings with C. pseudonaviculata spores under greenhouse conditions appeared to be a reliable tool for early selection of interesting prebreeding material. Overall, the four hybrid populations screened showed a segregating behaviour between their parents when determining the percentage of diseased leaves and lesion diameter. Genotypes were also found with an increased tolerance as compared to the parental species. Approximately 50% of the seedlings had the same score for both parameters after artificial inoculation in the greenhouse and in the field. Of the seedlings that showed severe symptoms in the greenhouse, <15% showed no disease symptoms in the field. Therefore, for larger breeding programmes, we propose a two‐step selection procedure: first artificial inoculation at seedling level to eliminate all genotypes with severe symptoms and then evaluation of the remaining seedlings in the field. Using this strategy, we were able to select several genotypes in our four hybrid populations with improved resistance to C. pseudonaviculata. [ABSTRACT FROM AUTHOR]
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- 2019
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23. Current and Emerging Phytophthoras: research supporting risk assessment and risk management (CEP)
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Turner, Judith, Riccioni, Luca, Heungens, Kurt, Meffert, Johan, Braganca, Helena, Webber, Joan, Choiseul, James, Schlenzig, Alexandra, Talgø, Venche, Stromeng, Gunn Mari, Campos Abad, Paloma, Perez Sierra, Ana, McCracken, Allistair, Gusina, Valentina, Lasner, Helena, and Brandt, Linda
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Euphresco, plant health, diagnostics, risk assessment, risk management, Phytophthora spp - Abstract
This EU-wide EUPHRESCO project brought together partners from nine countries in project meetings and workshops to exchange knowledge on diagnostic methodologies for Phytophthora species and facilitate the standardisation of protocols across Europe. Validation work on in-field diagnostic tests highlighted the effectiveness of the use of lateral flow devices (LFDs) to identify plants infected by Phytophthora species. However, the in-field PCR and LAMP tests, which were at that point still undergoing development and validation, showed a much lower rate of detection compared to the results from laboratory isolation and identification. Newly developed and validated real-time LAMP assays on the Genie II were demonstrated to be effective for detection of a range of Phytophthora species in different hosts and tissue types. The use of alkaline PEG extraction greatly increased the potential for use of LAMP-based testing outside the laboratory in a range of scenarios. This has led to the development of reagents in a kit format to increase accessibility and convenience for a range of potential end-users. Since the end of this project, the P. ramorum and P. kernoviae LAMP assays have been developed into kits, and the potential now exists for the other assays described in this report to be made available in the same way. Novel LAMP assays were developed and validated for use in detection of P. austocedrae, P. lateralis and P. pseudosyringae in the field. A generic LAMP assay for detection of Phytophthora species was also developed for use in any future outbreaks of Phytophthora species of quarantine importance. Analyses of the genotypes of 65 isolates of P. ramorum confirmed the existence of a group of isolates unique to the UK which continue to diversify as the pathogen spreads in the natural environment. No geographical or host specificity was detected for these groups although continuing diversification is a sign of growth and spread of the disease. In contrast, genotypic variation within a small number of isolates sourced from Portugal was very limited except for a single isolate whose genotype suggested that this isolate may have moved in trade between Spain and Portugal. This illustrates the capability of these analyses in detecting pathways of spread for the rarer genotypes and can be useful in calculation dispersal distances and potential rates of spread of pathogens. Clear distinctions were seen between UK and New Zealand isolates of P. kernoviae with no intermixing of genotypes between countries indicating no direct connection between the two populations and no evidence for NZ being the source of introduction of P. kernoviae to the UK. Genetic diversity was greater within the New Zealand population of P. kernoviae compared to that found in the UK suggesting that the population in the UK is more recent in its introduction. Extensive research and analysis from the UK on risk assessment and disease management in natural outbreaks have been shared with national representatives from nine EU countries, completing objectives for knowledge transfer and facilitating capabilities for response to any future outbreaks of Phytophthora species across Europe. An improvement in efficacy, versatility and provenance of diagnostic methodologies as outputs from this project could significantly enhance the development of improved surveillance strategies and hence aid timely risk analysis for current outbreaks as well as deliver generic approaches for future outbreaks caused by Phytophthora species. In addition, outputs from genotyping using microsatellite analysis, 454 and Illumina sequencing of P. ramorum isolates could inform risk assessments for epidemic development and assist in identification of pathways of disease entry and spread., Scientific report of the Euphresco funded project 'Current and Emerging Phytophthoras: research supporting risk assessment and risk management' (CEP)
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- 2014
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24. THE BELGIAN PLANT SENTINEL NETWORK.
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Ronse, Anne, Casteels, Hans, Chandelier, Anne, De Jonghe, Kris, Deeren, Anne-Marie, Groom, Quentin, Heungens, Kurt, Maes, Martine, Schmitz, Sophie, and Viaene, Nicole
- Published
- 2020
25. Proposal to conserve the name Cylindrocladium buxicola against C. pseudonaviculatum (Ascomycota)
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Henricot, Béatrice, David, John, Ivors, Kelly, Heungens, Kurt, Spooner, Brian, Pérez Sierra, Ana María, and Daughtrey, Margery L.
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PRODUCCION VEGETAL - Published
- 2012
26. Change of Mating Type in an EU1 Lineage Isolate of Phytophthora ramorum.
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Chandelier, Anne, Heungens, Kurt, and Werres, Sabine
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PHYTOPHTHORA ramorum , *PLANT growing media , *PLANT epidemiology , *PHYTOPATHOGENIC fungi , *REPRODUCTION - Abstract
All Phytophthora ramorum EU1 lineage isolates tested are of A1 mating type, except for three rare isolates from 2002 to 2003 from Belgium, which were originally assigned the A2 mating type. In one of these isolates (2338), a switch from A2 to A1 mating type was observed in 2006. This observation initiated a larger study in which all cultures and subcultures of the original three EU1 A2 isolates, maintained in three laboratories under different storage conditions, were checked for mating type change. The A2 to A1 mating type switch was observed in four of seven independently maintained isolates that were derived from isolate 2338 in two laboratories, using different transfer regimes and storage conditions. Following the mating type switch to A1 in these four derived isolates, no reversion back to A2 mating was observed, even after up to 5 years of additional isolate maintenance and several more subculturing events. The three other isolates that were derived from isolate 2338 as well as the other EU1 A2 isolates collected in 2002 and 2003 and stored in the same conditions did not display such mating type change. The potential causes of the mating type conversions as well as their epidemiological implications are discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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27. Identification and characterization of pathotypes in Puccinia horiana, a rust pathogen of Chrysanthemum x morifolium.
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Backer, Mathias, Alaei, Hossein, Bockstaele, Erik, Roldan-Ruiz, Isabel, Lee, Theo, Maes, Martine, and Heungens, Kurt
- Abstract
Puccinia horiana is the causal agent of chrysanthemum white rust or Japanese rust. This microcyclic autoecious rust has a quarantine status and can cause major damage in the commercial production of Chrysanthemum x morifolium. Given the international and often trans-continental production of planting material and cut flowers of chrysanthemum and the decreasing availability of registered fungicides in specific regions, breeding for resistance against P. horiana will gain importance and will need to involve the appropriate resistance genes for the pathotypes that may be present. As pathotypes have not been well characterized in this system, the main objective was to build an international collection of isolates and screen these on a large collection of cultivars to identify different pathotypes. Using a robust and high throughput bioassay, we tested 36 selected cultivars with 22 individual single-pustule isolates of P. horiana. The isolates originated from three different continents over 4 different collection years and included some isolates from cultivars previously reported as resistant. In most cases the bioassays resulted in a clear scoring of interaction phenotypes as susceptible or resistant, while in several cases consistent intermediate phenotypes were found, often on specific cultivars. Twenty-four of the cultivars gave a differential interaction phenotype profile. All isolates produced a unique profile, infecting a minimum of 4 and a maximum of 19 differential cultivars. Based on the Person analysis of these profiles, this pathosystem contains at least seven resistance genes (and seven avirulence genes), demonstrating the highly complex race structure in this pathosystem. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
28. Development of a multi-mycotoxin liquid chromatography/tandem mass spectrometry method for sweet pepper analysis.
- Author
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Monbaliu, Sofie, Van Poucke, Christof, Van Peteghem, Carlos, Van Poucke, Kris, Heungens, Kurt, and De Saeger, Sarah
- Published
- 2009
- Full Text
- View/download PDF
29. Response of Ants to a Deterrent Factor(s) Produced by the Symbiotic Bacteria of Entomopathogenic Nematodes.
- Author
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Xinsheng Zhou, Kaya, Harry K., Heungens, Kurt, and Goodrich-Blair, Heidi
- Subjects
- *
XENORHABDUS , *SYMBIOSIS , *NEMATODES - Abstract
Examines the production of an ant-deterrent factor (ADF) by Xenorhabdus nematophila and Photorhabdus luminescens, the symbiotic bacteria of the entomopathogenic nematodes. Effect of sucrose concentration on ADF activity; Time course of ADF production in vitro; Production of ADF activity in vivo.
- Published
- 2002
- Full Text
- View/download PDF
30. Discovery of a fourth evolutionary lineage of Phytophthora ramorum: EU2
- Author
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Van Poucke, Kris, Franceschini, Selma, Webber, Joan F., Vercauteren, Annelies, Turner, Judith A., McCracken, Alistair R., Heungens, Kurt, and Brasier, Clive M.
- Subjects
- *
BIOLOGICAL evolution , *PHYTOPHTHORA ramorum , *LINEAGE , *JAPANESE larch - Abstract
Abstract: Phytophthora ramorum is a recently introduced, aggressive Phytophthora species that has caused extensive mortality of oak and tanoak trees in the western USA and Japanese larch trees in the UK. P. ramorum is also present on Rhododendron, Camellia, and Viburnum in the nursery industry, which is thought to have been the pathway for its spread into new geographic regions including forests and natural ecosystems. Three lineages of P. ramorum have been described, informally designated EU1, NA1, and NA2, and each lineage is believed to originate from an as yet unknown exotic centre of origin. Preliminary SSR and sequence analysis of isolates from a UK P. ramorum survey revealed seven isolates with profiles that did not match the previously known lineages. Detailed SSR and multilocus sequence analysis of these isolates are presented, allowing us to assign these isolates to a new P. ramorum lineage, designated EU2. Although the known geographical origin of these isolates is currently limited to Northern Ireland and western Scotland, the EU2 lineage isolates have been obtained from four different host plants, including Japanese larch. All isolates are of A1 compatibility type, which implies that this finding does not increase the risk of outcrossing with the EU1 lineage isolates already present in the UK. The oldest EU2 strain was isolated in 2007 but no SSR-based intraEU2 lineage genotypic diversity was detected. The combination of these elements points to a recent introduction, despite emergency phytosanitary measures to control introduction and spread. A PCR-RFLP method for the rapid identification of EU2 lineage isolates is presented. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
31. Genetic diversity and mycotoxin production of Fusarium lactis species complex isolates from sweet pepper
- Author
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Van Poucke, Kris, Monbaliu, Sofie, Munaut, Françoise, Heungens, Kurt, De Saeger, Sarah, and Van Hove, François
- Subjects
- *
MYCOTOXINS , *FUSARIUM , *SWEET peppers , *BUTT rots , *RNA polymerases , *PLANT genetics , *LIQUID chromatography-mass spectrometry - Abstract
Abstract: An internal fruit rot disease of sweet peppers was first detected in Belgium in 2003. Research conducted mostly in Canada indicates that this disease is primarily caused by Fusarium lactis Pirotta. Ninety-eight Fusarium isolates obtained from diseased sweet peppers from Belgium, as well as from other countries (Canada, the Netherlands and the United Kingdom) were identified by sequencing the translation elongation factor 1α (EF). Of these 98 isolates, 13 were identified as F. oxysporum Schltdl., nine as F. proliferatum (Matsush.) Nirenberg and two belonged to clade 3 of the F. solani species complex. Of the 74 remaining isolates, the EF sequence showed 97% to 98% similarity to F. lactis. Of these isolates, the β-tubulin (TUB), calmodulin (CAM) and the second largest subunit of RNA polymerase II (RPB2) genes were also sequenced. Analysis of the combined sequences revealed that the 74 isolates share nine combined sequences that correspond to nine multilocus sequence types (STs), while the F. lactis neotype strain and one other strain, both isolated from figs, form a separate ST. Together, these 10 STs represent a monophyletic F. lactis species complex (FLASC). An unusually high level of genetic diversity was observed between (groups of) these STs. Two of them (ST5 and ST6) fulfilled the criteria for species recognition based on genealogical exclusivity and together represent a new monophyletic species lineage (FLASC-1). The seven other STs, together with the F. lactis neotype ST, form a paraphyletic species lineage in the African clade of the Gibberella fujikuroi species complex (GFSC). From each of the 10 STs, the mycotoxin production was assessed using a multi-mycotoxin liquid chromatography mass spectrometry method. Out of the 27 analyzed mycotoxins, beauvericin and fumonisins were detected in sweet pepper tissue and in maize kernels. The 10 STs clearly differed in the amount of mycotoxin produced, but there was only limited congruence between the production profile and the phylogenetic analysis. Furthermore, the morphological characterization (based on mycelial growth rate and the length of macroconidia) showed distinct differences between the 10 STs, but again there was limited congruence with the phylogenetic results. In conclusion, the data presented in this study demonstrate that 75% of the isolates obtained from sweet pepper with internal fruit rot belong to a F. lactis species complex (FLASC), including a new FLASC-1 monophyletic species, and that the members of this complex display great genetic and phenotypic diversity. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
32. Aberrant genome size and instability of Phytophthora ramorum oospore progenies
- Author
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Vercauteren, Annelies, Boutet, Xavier, D’hondt, Liesbet, Van Bockstaele, Erik, Maes, Martine, Leus, Leen, Chandelier, Anne, and Heungens, Kurt
- Subjects
- *
PHYTOPHTHORA ramorum , *PLANT genetics , *PHYTOPATHOGENIC microorganisms , *SEXUAL cycle , *SUDDEN oak death , *MEIOSIS , *FLOW cytometry , *ANEUPLOIDY , *OOMYCETES - Abstract
Abstract: The functionality of the sexual cycle in the heterothallic pathogen Phytophthora ramorum, causal agent of Sudden Oak Death, has recently been demonstrated. Sexual reproduction could create genotypic variation and increase the pathogen’s ability to adapt to other host plants or changing environments. Genetic characterization using co-dominant microsatellite markers and flow cytometry of single-oospore progeny of crosses between a European A1 isolate and North American or European A2 isolates revealed a considerable number of non-Mendelian inheritance events. This includes inheritance of more than two alleles at a locus and non-inheritance of alleles from one parent at another locus. The progenies were mitotically unstable: zoospore and hyphal tip derivatives of the progenies showed genotypic rearrangements and phenotypic variation. Flow cytometry confirmed variation and instability in DNA content of the single-oospore progenies. This indicates that single-oospore progenies not only display aberrant genomic and phenotypic variation due to meiotic irregularities, but also extra variation as a result of post-meiotic genomic rearrangements. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
33. Phytophthora ramorum in Canada: Evidence for Migration Within North America and from Europe.
- Author
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Goss, Erica M., Larsen, Meg, Vercauteren, Annelies, Werres, Sabine, Heungens, Kurt, and Grünwald, Niklaus J.
- Subjects
- *
PHYTOPHTHORA ramorum , *PHYTOPHTHORA , *OAK diseases & pests , *ORNAMENTAL plants , *PLANT nurseries - Abstract
Phytophthora ramorum, the cause of sudden oak death on oak and ramorum blight on woody ornamentals, has been reported in ornamental nurseries on the West Coast of North America from British Columbia to California. Long-distance migration of P. ramorum has occurred via the nursery trade, and shipments of host plants are known to have crossed the U.S.-Canadian border. We investigated the genotypic diversity of P. ramorum in Canadian nurseries and compared the Canadian population with U.S. and European nursery isolates for evidence of migration among populations. All three of the P. ramorum clonal lineages were found in Canada but, unexpectedly, the most common was the NA2 lineage. The NAI clonal lineage, which has been the most common lineage in U.S. nurseries, was found relatively infrequently in Canada, and these isolates may have been the result of migration from the United States to Canada. The EU1 lineage was observed almost every year and shared multilocus genotypes with isolates from Europe and the United States. Estimation of migration rates between Europe and North America indicated that migration was higher from Europe to North America than vice versa, and that unidirectional migration from Europe to North America was more likely than bidirectional migration. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
34. Phylogenetic relationships of Puccinia horiana and other rust pathogens of Chrysanthemum × morifolium based on rDNA ITS sequence analysis
- Author
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Alaei, Hossein, De Backer, Mathias, Nuytinck, Jorinde, Maes, Martine, Höfte, Monica, and Heungens, Kurt
- Subjects
- *
CHRYSANTHEMUM diseases & pests , *PLANT molecular phylogenetics , *PUCCINIA , *RUST fungi , *PHYTOPATHOGENIC fungi , *NUCLEOTIDE sequence , *RIBOSOMAL DNA , *PLANT-pathogen relationships - Abstract
Abstract: Isolates of the most important Puccinia species that have been reported on Chrysanthemum × morifolium were collected and the sequences of their ribosomal DNA internal transcribed spacers ITS1 and ITS2 were determined and used as phylogenetic markers. The focus of this study was on Puccinia horiana, due to its quarantine status and its impact in commercial chrysanthemum production. Three technical adjustments were needed to reliably obtain the nucleotide sequences starting from fresh or dried samples. The complete rDNA ITS nucleotide sequences of P. horiana, Puccinia chrysanthemi, and Puccinia tanaceti isolates of varying age and geographic origin were determined. We also identified an as yet undescribed Puccinia species on six old herbarium samples from chrysanthemum. This new species is morphologically similar to P. chrysanthemi and near identical to recent rust samples from Artemisia tridentata. P. tanaceti could not be confirmed as a pathogen of chrysanthemum. Different rDNA ITS sequences were present in P. horiana, with intra-isolate and inter-isolate variability in the length of three nucleotide repeat regions in the different rDNA tandem copies. We also identified three ITS types within P. horiana, with the rarer types displaying up to 67bp nucleotide sequence differences. These rarer ITS types were detected at low copy number in all isolates. In general, very little rDNA ITS sequence variation was observed between P. horiana isolates from 1903 and 2003, and among isolates from different continents. Phylogenetic analyses using distance, Maximum Likelihood and Bayesian methods confirmed P. horiana, P. chrysanthemi, and the new Puccinia sp. as well-resolved groups, with P. horiana clustering in the clade where the economically important rust species of the Poaceae are located, and P. chrysanthemi and the new Puccinia sp. clustering in the clade where the majority of the rust fungi with hosts in the Asteraceae is located. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
35. Molecular detection of Puccinia horiana in Chrysanthemum x morifolium through conventional and real-time PCR
- Author
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Alaei, Hossein, Baeyen, Steve, Maes, Martine, Höfte, Monica, and Heungens, Kurt
- Subjects
- *
PUCCINIA , *CHRYSANTHEMUM diseases & pests , *FUNGAL diseases of plants , *POLYMERASE chain reaction , *EXTRACTION (Chemistry) , *PLANT clones , *PATHOGENIC fungi - Abstract
Abstract: Puccinia horiana Henn. is a quarantine organism and one of the most important fungal pathogens of Chrysanthemum x morifolium cultivars grown for cut flower or potted plant production (florist''s chrysanthemum) in several regions of the world. Highly specific primer pairs were identified for conventional, nested, and real-time PCR detection of P. horiana based on the specific and sensitive PCR amplification of selected regions in the internal transcribed spacers (ITS1 and ITS2) of the nuclear ribosomal DNA (rDNA). Using these different PCR versions, 10 pg, 10 fg, and 5 fg genomic DNA could be detected, respectively. When using cloned target DNA as template, the detection limits were 5000, 50, and 5 target copies, respectively. These detection limits were not affected by a background of chrysanthemum plant DNA. The DNA extraction method was optimized to maximize the recoverability of the pathogen from infected plant tissue. A CTAB extraction protocol or a selection of commercial DNA extraction methods allowed the use of 10 ng total (plant+pathogen) DNA without interference of PCR inhibitors. Due to the specificity of the primers, SYBR Green I technology enabled reliable real time PCR signal detection. However, an efficient TaqMan probe is available. The lowest proportion of infected plant material that could still be detected when mixed with healthy plant material was 0.001%. The real-time PCR assay could detect as few as eight pure P. horiana basidiospores, demonstrating the potential of the technique for aerial detection of the pathogen. The amount of P. horiana DNA in plant tissue was determined at various time points after basidiospore inoculation. Using the real-time PCR protocol, it was possible to detect the pathogen immediately after the inoculation period, even though the accumulation of pathogen DNA was most pronounced near the end of the latent period. The detection system proved to be accurate and sensitive and could help not only in pathogen diagnosis but also in pathogen monitoring and disease forecasting systems. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
36. Global distribution of mating types shows limited opportunities for mating across populations of fungi causing boxwood blight disease.
- Author
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Malapi-Wight, Martha, Veltri, Daniel, Gehesquière, Bjorn, Heungens, Kurt, Rivera, Yazmín, Salgado-Salazar, Catalina, and Crouch, Jo Anne
- Subjects
- *
BOXWOOD , *BLIGHT diseases (Botany) , *MYCOSES , *FUNGI , *SPECIES hybridization , *NATURAL landscaping - Abstract
• MAT1 loci with heterothallic organization identified from the two Calonectria that cause boxwood blight. • Calonectria pseudonaviculata isolates possess MAT1-2 mating type idiomorphs. • Calonectria henricotiae isolates possess MAT1-1 mating type idiomorphs. • Phylogenomic estimates place divergence of the boxwood blight pathogens at ∼2.1 Mya. • Minimal divergence between Che and Cps was observed in the genome region proximal to the MAT1 locus. Boxwood blight is a disease threat to natural and managed landscapes worldwide. To determine mating potential of the fungi responsible for the disease, Calonectria pseudonaviculata and C. henricotiae , we characterized their mating-type (MAT) loci. Genomes of C. henricotiae , C. pseudonaviculata and two other Calonectria species (C. leucothoes , C. naviculata) were sequenced and used to design PCR tests for mating-type from 268 isolates collected from four continents. All four Calonectria species have a MAT locus that is structurally consistent with the organization found in heterothallic ascomycetes, with just one idiomorph per individual isolate. Mating type was subdivided by species: all C. henricotiae isolates possessed the MAT1-1 idiomorph, whereas all C. pseudonaviculata isolates possessed the MAT1-2 idiomorph. To determine the potential for divergence at the MAT1 locus to present a barrier to interspecific hybridization, evolutionary analysis was conducted. Phylogenomic estimates showed that C. henricotiae and C. pseudonaviculata diverged approximately 2.1 Mya. However, syntenic comparisons, phylogenetic analyses, and estimates of nucleotide divergence across the MAT1 locus and proximal genes identified minimal divergence in this region of the genome. These results show that in North America and parts of Europe, where only C. pseudonaviculata resides, mating is constrained by the absence of MAT1-1. In regions of Europe where C. henricotiae and C. pseudonaviculata currently share the same host and geographic range, it remains to be determined whether or not these two recently diverged species are able to overcome species barriers to mate. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
37. Cylindrocladium buxicola nom. cons. prop. (syn. Calonectria pseudonaviculata) on Buxus: molecular characterization, epidemiology, host resistance and fungicide control
- Author
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Gehesquière, Bjorn, Höfte, Monica, and Heungens, Kurt
- Subjects
molecular characterization ,integrated pest management ,Cylindrocladium buxicola ,Biology and Life Sciences ,epidemiology ,fungicide control ,Buxus ,host resistance ,Calonectria pseudonaviculata - Abstract
Buxus soorten zijn populaire tuinplanten, omwille van hun diversiteit in vorm, grootte en groeisnelheid, hun gemak in onderhoud en veelzijdigheid in gebruik. Midden jaren 90 werd de buxussector voor het eerst geconfronteerd met een voordien onbekende bladvlekkenziekte, veroorzaakt door de schimmel Cylindrocladium buxicola. De pathogeen heeft zich in korte tijd doorheen de commerciële buxussector verspreid, en veroorzaakt zware economische verliezen in de meeste gebieden waar Buxus wordt gekweekt. Bovendien bedreigt de ziekte historische buxustuinen en wilde Buxus populaties in Europa en Azië. Door de relatief recente detectie, was er slechts weinig gekend over de biologie van deze pathogeen en de gevoeligheid van verschillende Buxus soorten en cultivars. Om een duurzame, geïntegreerde beheersing te bewerkstelligen is deze informatie echter essentieel. Het verkrijgen van deze kennis was de hoofddoelstelling van dit proefschrift. De eerste doelstelling in dit werk was de genetische en fenotypische karakterisering van een internationale C. buxicola collectie (1998 tot 2013). Binnen deze collectie werden twee klonale groepen geïdentificeerd (G1 en G2), ontstaan als gevolg van twee onafhankelijke, recente introducties. Door middel van nieuw ontwikkelde microsatelliet merkers werden binnen de dominante G1 populatie verbanden aangetoond tussen het genotype en de geografische oorsprong van de isolaten. Isolaten van de G2 populatie vertoonden een hogere temperatuurtolerantie en lagere gevoeligheid ten opzichte van specifieke fungicidengroepen, wat belangrijke gevolgen kan hebbent voor de bestrijding en de epidemiologie van deze schimmel. Als tweede doelstelling werd de epidemiologie van de pathogeen bestudeerd. Nieuw ontwikkelde moleculaire detectietools werden gebruikt om verspreiding, overleving en insleep van C. buxicola op bedrijfsschaal na te gaan. De experimenten toonden aan dat korte afstandsverspreiding van C. buxicola voornamelijk via opspattende regen gebeurt. Lange afstandsverspreiding en insleep lijkt voornamelijk te gebeuren via geïnfecteerd plantmateriaal. Verspreiding en insleep door gecontamineerde werkkledij en snoeimaterialen bleek mogelijk, maar weinig efficiënt. Een derde doelstelling was de bepaling van de gevoeligheid van een reeks Buxus soorten en cultivars, en de overerving van resistentie. Geen enkele van de geteste Buxus soorten bleek immuun te zijn tegen C. buxicola. Er werden wel grote verschillen in gevoeligheid waargenomen onder semi-praktijkomstandigheden. B. sempervirens en zijn cultivars bleken over het algemeen het meest gevoelig. Door middel van fluorescentie-microscopie werden tussen soorten significante verschillen gevonden in de afzet van fenolische componenten na infectie, wat een aanwijzing is voor verschillen in de aard, de reactiesnelheid en het niveau van induceerbare verdedigings-responsen. Er werd een complexe, niet-Mendeliaanse overerving van resistentie vastgesteld. Als laatste doelstelling werd de preventieve en/of curatieve werking nagegaan van 22 commercieel beschikbare fungiciden. Verschillende producten vertoonden een goede tot uitstekende contact werking of systemische werking tegen C. buxicola. De gecombineerde kennis verworven tijdens dit onderzoek levert een belangrijke bijdrage bij de overstap naar een duurzame, geïntegreerde beheersing van C. buxicola in Buxus.
- Published
- 2014
38. Production and migration of mycotoxins in sweet pepper analyzed by Multimycotoxin LC-MS/MS.
- Author
-
Monbaliu S, Van Poucke K, Heungens K, Van Peteghem C, and De Saeger S
- Subjects
- Capsicum chemistry, Chromatography, High Pressure Liquid, Depsipeptides analysis, Food Contamination analysis, Fruit chemistry, Fruit microbiology, Fumonisins analysis, Mycotoxins analysis, Plant Diseases microbiology, Tandem Mass Spectrometry, Capsicum microbiology, Fusarium growth & development, Fusarium metabolism, Mycotoxins biosynthesis, Mycotoxins metabolism
- Abstract
In this work the presence and migration behavior of mycotoxins formed in sweet pepper, inoculated by Fusarium species involved in internal fruit rot, were investigated. Two different commercial sweet pepper cultivars were inoculated with two different Fusarium proliferatum isolates that were sampled from diseased peppers. After 10 days of incubation at 20 °C in a closed container, the lesion caused by the fungal infection was dissected. Around the lesion, up to three concentric rings of pepper fruit tissue with a width of 5 mm were cut out and analyzed using a multimycotoxin LC-MS/MS method. The analyses resulted in the detection of beauvericin and fumonisins B(1), B(2), and B(3). Beauvericin was detected only in the lesions (95%), and the levels varied between 67 and 73800 μg/kg. Fumonisins B(1), B(2), and B(3) were detected in the lesions and in the surrounding tissue, indicating migration of these toxins into healthy parts of the sweet pepper. In the lesion the fumonisin B(1) level varied between 690 and 104000 μg/kg. Even in the outer ring fumonisin B(1) was still present. Mostly it was present at a lower level than in the lesion, with a maximum level of 556 μg/kg. A similar migration behavior was obtained for fumonisins B(2) and B(3), but lower levels were detected in the lesions, up to 10900 and 1287 μg/kg, respectively. The analysis of 20 pepper samples resulted in the detection of beauvericin or alternariol. Seven samples were contaminated, and the level of beauvericin was 124 μg/kg (N = 1), whereas the level of alternariol varied from below the LOQ (6.6 μg/kg) to 101 μg/kg (N = 6).
- Published
- 2010
- Full Text
- View/download PDF
39. Standardizing the nomenclature for clonal lineages of the sudden oak death pathogen, Phytophthora ramorum.
- Author
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Grünwald NJ, Goss EM, Ivors K, Garbelotto M, Martin FN, Prospero S, Hansen E, Bonants PJ, Hamelin RC, Chastagner G, Werres S, Rizzo DM, Abad G, Beales P, Bilodeau GJ, Blomquist CL, Brasier C, Brière SC, Chandelier A, Davidson JM, Denman S, Elliott M, Frankel SJ, Goheen EM, de Gruyter H, Heungens K, James D, Kanaskie A, McWilliams MG, Man in 't Veld W, Moralejo E, Osterbauer NK, Palm ME, Parke JL, Sierra AM, Shamoun SF, Shishkoff N, Tooley PW, Vettraino AM, Webber J, and Widmer TL
- Subjects
- Clone Cells, Genotype, Geography, Phytophthora genetics, Phytophthora isolation & purification, Phylogeny, Phytophthora classification, Phytophthora cytology, Plant Diseases microbiology, Quercus microbiology, Terminology as Topic
- Abstract
Phytophthora ramorum, the causal agent of sudden oak death and ramorum blight, is known to exist as three distinct clonal lineages which can only be distinguished by performing molecular marker-based analyses. However, in the recent literature there exists no consensus on naming of these lineages. Here we propose a system for naming clonal lineages of P. ramorum based on a consensus established by the P. ramorum research community. Clonal lineages are named with a two letter identifier for the continent on which they were first found (e.g., NA = North America; EU = Europe) followed by a number indicating order of appearance. Clonal lineages known to date are designated NA1 (mating type: A2; distribution: North America; environment: forest and nurseries), NA2 (A2; North America; nurseries), and EU1 (predominantly A1, rarely A2; Europe and North America; nurseries and gardens). It is expected that novel lineages or new variants within the existing three clonal lineages could in time emerge.
- Published
- 2009
- Full Text
- View/download PDF
40. Response of ants to a deterrent factor(s) produced by the symbiotic bacteria of entomopathogenic nematodes.
- Author
-
Zhou X, Kaya HK, Heungens K, and Goodrich-Blair H
- Subjects
- Animals, Hydrogen-Ion Concentration, Molecular Weight, Phenotype, Sucrose pharmacology, Ants drug effects, Enterobacteriaceae metabolism, Rhabditoidea microbiology, Symbiosis
- Abstract
The production of an ant-deterrent factor(s) (ADF) by Xenorhabdus nematophila and Photorhabdus luminescens, the symbiotic bacteria of the nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, respectively, was examined. In addition to an in vivo assay in which bacteria were tested for their ability to produce ADF within insect cadavers (M.E. Baur, H. K. Kaya, and D. R. Strong, Biol. Control 12:231-236, 1998), an in vitro microtiter dish assay was developed to monitor ADF activity produced by bacteria grown in cultures. Using these methods, we show that ADF activity is present in the supernatants of bacterial cultures, is filterable, heat stable, and acid sensitive, and passes through a 10-kDa-pore-size membrane. Thus, ADF appears to be comprised of a small, extracellular, and possibly nonproteinaceous compound(s). The amount of ADF repellency detected depends on the ant species being tested, the sucrose concentration (in vitro assays), and the strain, form, and age of the ADF-producing bacteria. These findings demonstrate that the symbiotic bacteria of some species of entomopathogenic nematodes produce a compound(s) that deters scavengers such as ants and thus could protect nematodes from being eaten during reproduction within insect cadavers.
- Published
- 2002
- Full Text
- View/download PDF
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