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Dirk De Waele - One of the best experts on this subject based on the ideXlab platform.
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phenalenone type phytoalexins mediate resistance of banana plants musa spp to the burrowing nematode Radopholus similis
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Dirk Holscher, Dirk De Waele, Suganthagunthalam Dhakshinamoorthy, Theodore Alexandrov, Michael Becker, Tom Bretschneider, Andreas Buerkert, Anna C Crecelius, Annemie ElsenAbstract:The global yield of bananas—one of the most important food crops—is severely hampered by parasites, such as nematodes, which cause yield losses up to 75%. Plant–nematode interactions of two banana cultivars differing in susceptibility to Radopholus similis were investigated by combining the conventional and spatially resolved analytical techniques 1H NMR spectroscopy, matrix-free UV-laser desorption/ionization mass spectrometric imaging, and Raman microspectroscopy. This innovative combination of analytical techniques was applied to isolate, identify, and locate the banana-specific type of phytoalexins, phenylphenalenones, in the R. similis-caused lesions of the plants. The striking antinematode activity of the phenylphenalenone anigorufone, its ingestion by the nematode, and its subsequent localization in lipid droplets within the nematode is reported. The importance of varying local concentrations of these specialized metabolites in infected plant tissues, their involvement in the plant’s defense system, and derived strategies for improving banana resistance are highlighted.
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Variability in reproductive fitness and virulence of four Radopholus similis nematode populations associated with plantains and banana (Musa spp.) in Uganda
International Journal of Pest Management, 2013Co-Authors: Carine Dochez, Jolly Dusabe, Abdou Tenkouano, Rodomiro Ortiz, James Whyte, Dirk De WaeleAbstract:Burrowing nematodes (Radopholus similis) are among the most serious nematode pests affecting banana and plantain (Musa spp.). In Uganda, bananas, which are known locally as “matooke”, are the main staple. Radopholus similis populations collected in four banana-growing locations (Namulonge, Mbarara, Ikulwe and Mukono) were cultured monoxenically on carrot discs, and we compared the variability in reproductive fitness and virulence (as a function of time and inoculum level) of different populations of R. similis from Uganda. Their level of pathogenicity was determined by assessing the nematode reproductive ratio; that is, final population divided by the initial population. These in vitro experiments showed that the R. similis population from Mbarara had the highest reproduction ratio, while the population from Mukono had the lowest reproduction ratio. This assessment along with pathogenicity experiments on host Musa plants provides a means for defining pathogenicity groups among R. similis populations.
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In vitro nematicidal effect of endophytic Fusarium oxysporum against Radopholus similis, Pratylenchus goodeyi and Helicotylenchus multicinctus.
Nematropica, 2011Co-Authors: P. Van Dessel, Dirk De Waele, Thomas Dubois, Daniel Coyne, J. FrancoAbstract:Van Dessel, P., D. Coyne, T. Dubois, D. De Waele and J. Franco. 2011. In vitro nematicidal effect of endophytic Fusarium oxysporum against Radopholus similis, Pratylenchus goodeyi and Helicotylenchus multicinctus. Nematropica 41:154-160. Endophytic fungi colonize most plants, causing no damage to their hosts, and often extending benefits, such as enhanced protection against various biotic and abiotic constraints. In the current study, three experiments assessed the activity of secondary metabolites of three strains of endophytic Fusarium oxysporum (Emb2.4o, Eny1.31i and V5w2) against the banana (Musa spp.) root-parasitic nematodes Radopholus similis, Pratylenchus goodeyi and Helicotylenchus multicinctus under different laboratory procedures. All experiments showed higher nematode mortality after 24 h exposure for each endophyte culture filtrate compared to control treatments after 24 h exposure. Helicotylenchus multicinctus was less sensitive to endophytic treatments than R. similis and P. goodeyi; and R. similis was more sensitive than P. goodeyi to strain V5w2 even at lower filtrate concentrations. Based on motility of R. similis and P. goodeyi, light (14 L: 10 D h) had no significant effect on endophyte culture filtrates (Emb2.4o and V5w2). These results indicate the potential of endophytic F. oxysporum as an environmentally sensitive management strategy for a range of plant-parasitic nematodes on banana, although more detail is required on the identification of the toxic metabolites involved. Van Dessel, P., D. Coyne, T. Dubois, D. De Waele and J. Franco. 2011. In vitro nematicidal effect of endophytic Fusarium oxysporum against Radopholus similis, Pratylenchus goodeyi and Helicotylenchus multicinctus. Nematropica 41:154-160. Los hongos endofiticos colonizan la mayoria de las plantas sin causar dano y a veces brindan beneficios tales como la proteccion contra diversos agentes bioticos y abioticos. En este estudio se llevaron a cabo tres experimentos in vitro para evaluar la actividad de metabolitos secundarios de tres cepas de Fusarium oxysporum (Emb2.4o, Eny1.31i y V5w2) contra tres nematodos fitoparasitos del banano, Radopholus similis, Pratylenchus goodeyi y Helicotylenchus multicinctus. Todos los experimentos mostraron mayor mortalidad de los nematodos despues de 24h de exposicion al filtrado de cada cultivo del hongo comparados con los controles. Helicotylenchus multicinctus fue menos sensible a los tratameintos que R. similis y P. goodeyi; y R. similis fue mas sensible que P. goodeyi a la cepa V5w2 aun en concentraciones bajas del filtrado. Con base en la motilidad de R. similis y P. goodeyi, la luz (14 L: 10 D h) no tuvo efecto significativo sobre los filtrados del cultivo del hongo (Emb2.4o and V5w2). Estos resultados indican que F. oxysporum puede ser una opcion de manejo ambientalmente viable para algunos nematodos fitoparasitos del banano, aunque se requiere mas informacion acerca de los metabolitos toxicos involucrados en el control.
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Reaction of Musa hybrids to the burrowing nematode, Radopholus similis.
Indian journal of nematology, 2010Co-Authors: Sukhen Chandra Das, T.n. Balamohan, K. Poornima, N. Seenivasan, I. Van Den Bergh, Dirk De WaeleAbstract:Twenty four elite banana hybrids, six diploids (AA and AB), five triploids (AAA and AAB), ten tetraploids (AABB) and three pentaploids (AAABB) were screened under field conditions for their reaction to Radopholus similis. Among them, H 531 and H 516 were rated resistant, while H 511, H 534, H 537, H 571, H 572 and H 589 were rated tolerant. The remaining accessions were rated susceptible. Peroxidase, Polyphenol oxidase, phenylalanine ammonia lyase enzyme activities and total phenol contents in roots were higher in H 531 and H 516 than in the other hybrids. H 531 recorded relatively higher yield of 13.5 kg/plant.
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Host plant resistance to Radopholus similis in a diploid banana hybrid population
Nematology, 2009Co-Authors: Carine Dochez, Abdou Tenkouano, Rodomiro Ortiz, James Whyte, Dirk De WaeleAbstract:The objective of the research was to study the genetics of host plant resistance to Radopholus similis in a diploid banana population. Screening of a hybrid population and determination of the segregation ratios can provide information on the inheritance and number of alleles controlling this trait in banana. The diploid banana hybrid population used was derived by crossing the diploid hybrids TMB2x 6142-1 and TMB2x 8075-7. The diploid banana hybrid population was evaluated with the individual root inoculation method using an R. similis population from Namulonge, Uganda. Of the 81 hybrids evaluated, 37 hybrids were resistant, 13 hybrids were partially resistant and 31 hybrids were susceptible to R. similis. After chi-square analysis, the results indicated that resistance to R. similis is controlled by two dominant genes, A and B, both with additive and interactive effects, whereby recessive bb suppresses dominant A.
Annemie Elsen - One of the best experts on this subject based on the ideXlab platform.
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phenalenone type phytoalexins mediate resistance of banana plants musa spp to the burrowing nematode Radopholus similis
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Dirk Holscher, Dirk De Waele, Suganthagunthalam Dhakshinamoorthy, Theodore Alexandrov, Michael Becker, Tom Bretschneider, Andreas Buerkert, Anna C Crecelius, Annemie ElsenAbstract:The global yield of bananas—one of the most important food crops—is severely hampered by parasites, such as nematodes, which cause yield losses up to 75%. Plant–nematode interactions of two banana cultivars differing in susceptibility to Radopholus similis were investigated by combining the conventional and spatially resolved analytical techniques 1H NMR spectroscopy, matrix-free UV-laser desorption/ionization mass spectrometric imaging, and Raman microspectroscopy. This innovative combination of analytical techniques was applied to isolate, identify, and locate the banana-specific type of phytoalexins, phenylphenalenones, in the R. similis-caused lesions of the plants. The striking antinematode activity of the phenylphenalenone anigorufone, its ingestion by the nematode, and its subsequent localization in lipid droplets within the nematode is reported. The importance of varying local concentrations of these specialized metabolites in infected plant tissues, their involvement in the plant’s defense system, and derived strategies for improving banana resistance are highlighted.
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Cryopreservation of Radopholus similis, a tropical plant-parasitic nematode.
Cryobiology, 2007Co-Authors: Annemie Elsen, Dirk De Waele, Rony Swennen, Salvador Ferrandis Vallterra, Tom Van Wauwe, Trinh Thi Thu Thuy, Bart PanisAbstract:For obligate plant-parasitic nematodes, cryopreservation has advantages over the usual preservation methods on whole plants or axenic culture systems, because the latter two are labourious and time and space consuming. In addition, cross contamination among different isolates can occur easily. Moreover, specific genetic studies require maintenance of the original population. The nematode under investigation, Radopholus similis, is a plant-parasitic nematode from the humid tropics. Therefore, any treatment at low temperatures is likely to add extra stress to the nematode, making the development of a cryopreservation protocol extremely difficult. In this paper, we describe experiments to achieve a successful cryopreservation protocol for the tropical nematode R. similis using vitrification solution-based methods based on a well defined mixture of cryoprotectants in combination with ultra-rapid cooling and thawing rates. A two-step treatment was used consisting of an incubation in glycerol followed by the application of a vitrifying mixture of methanol, glycerol and glucose. After cryopreservation, the pathogenicity of the nematodes was not altered, since they could infect and reproduce on carrot discs after recovery in the Ringer solution. The cryopreservation method described can be used for routine cryopreservation of R. similis lines from different origins.
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Effect of plant lectins on the host-finding behaviour of Radopholus similis
Nematology, 2003Co-Authors: Nathalie Wuyts, Dirk De Waele, Rony Swennen, Annemie Elsen, Els Van Damme, Willy J. Peumans, Laszlo SagiAbstract:Summary ‐ The motility and the chemotactic response towards plant roots of Radopholus similis , after treatment with novel types of lectins, were examined in vitroby analysing movement tracks on agar plates. Six plant lectins belonging to e ve different lectin families and a banana thaumatin-like protein (BanTLP) were included in the experiment. A 1% concentration of Phaseolus vulgaris agglutinin (PHA) had an adverse effect on the motility of R. similisfemales: 63% showed no or very little movement on agar plates compared to an average of 33% for other lectins and 3% for the control treatment. A 0.05% concentration of PHA still reduced the motility of R. similis females by 75%. Concanavalin A and wheat germ agglutinin did not alter the chemotactic response towards plant roots, despite binding of both lectins to R. similis. In contrast, Galanthus nivalis agglutinin (GNA) reduced orientated movement of R. similis towards plant roots. Subsequently, secretions of R. similis were stained with Coomassie Brilliant Blue R. Nematodes treated with GNA produced secretions less abundantly compared to the control treatment and BanTLP. The other lectins in the experiment had variable effects on secretion.
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In vitro screening for resistance to Radopholus similis in Musa spp.
Plant Science, 2002Co-Authors: Annemie Elsen, Ruth Stoffelen, Nguyen Thi Tuyet, Hughues Baimey, Hervé Dupré De Boulois, Dirk De WaeleAbstract:Abstract The burrowing nematode, Radopholus similis , is the most important nematode pest of banana and plantain worldwide, causing severe yield losses in commercial and local consumption cultivars. Chemical control is currently the most-used method to manage the nematodes, although nematicides are dangerous, toxic and expensive. Therefore, nematode control through genetic improvement is widely encouraged. Protocols have been set up to detect sources of resistance in the existing Musa germplasm, but the screening under greenhouse and field conditions is laborious and time consuming. In vitro screening could facilitate this process by picking up sources of resistance at an early phase. In this study, a procedure for in vitro screening for the resistance to R. similis was set up by determining the optimal incubation time and the optimal nematode inoculum. In a second step, the optimized procedure was confirmed by screening a selection of Musa varieties with a known host plant response. Except for ‘Yangambi Km5’, their host response under in vitro conditions corresponded to their host response under greenhouse or field conditions. The susceptible status of ‘Grande Naine’, ‘Gros Michel’ and ‘Cachaco’ was confirmed, as well as the resistant status of ‘Pisang Jari Buaya’ and ‘SH-3142’.
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Effects of Glomus intraradices on the reproduction of the burrowing nematode (Radopholus similis) in dixenic culture
Mycorrhiza, 2001Co-Authors: Annemie Elsen, Stephan Declerck, Dirk De WaeleAbstract:The effects of Glomus intraradices on the reproduction of the burrowing nematode Radopholus similis were studied under dixenic culture conditions. The life cycles of both the arbuscular mycorrhizal fungus (AMF) and the nematode were completed in presence of each other and a transformed carrot root as host. The AMF suppressed the R. similis population by almost 50% and thus increased protection of the root against the nematode. This reduction was significant for both females and males within roots. There was no correlation between nematode population density and either AMF internal root colonization, external hyphal development or spore production. These results demonstrate that the dixenic system, although artificial, is a valuable tool for studying AMF–nematode interactions, complementing the classical experimental approaches.
Chun Chen - One of the best experts on this subject based on the ideXlab platform.
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Screening of reference genes in real-time PCR for Radopholus similis.
PeerJ, 2019Co-Authors: Jun-yi Li, Wan-zhu Chen, Si-hua Yang, Chun-ling Xu, Xin Huang, Chun ChenAbstract:Six candidate reference genes were chosen from the transcriptome database of Radopholus similis using the bioinformatics method, including four conventional reference genes (actin, Eukaryotic translation initiation factor 5A (eIF5A), Tubulin alpha (a-tubulin), ubiquitin (UBI)) and two new candidate reference genes (Ribosomal protein S21 (Rps21) and Serine/threonine protein phosphatase PP1-β catalytic subunit (β-PP1)). In addition, a traditional reference gene 18S ribosomal RNA (18S rRNA) obtained from NCBI databases was also added to the analysis. Real-time PCR was used to detect the expression of seven candidate reference genes in six populations of R. similis and four developmental stages (female, male, larva and egg) of a population. The stability of the expression of candidate genes was evaluated by three software programs, BestKeeper, geNorm and NormFinder. The results showed that eIF5A is the most suitable reference gene for gene functional research of different populations, while both Rps21 and eIF5A are the most suitable reference genes for different developmental stages of a population. Therefore, eIF5A is the best reference gene for studying R. similis. However, one defect of this study is that only seven candidate reference genes were analyzed; ideally, more genes should be tested.
Si-hua Yang - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Neoseiulus barkeri (Acari: Phytoseiidae) for the control of plant parasitic nematodes, Radopholus similis (Tylenchida: Pratylenchidae) and Meloidogyne incognita (Tylenchida: Heteroderidae)
Biocontrol Science and Technology, 2019Co-Authors: Si-hua Yang, Zhou Wanqin, Dong-wei Wang, Hui XieAbstract:Radopholus similis (Cobb) Thorne (Tylenchida: Pratylenchidae) and Meloidogyne incognita Kofoid and White (Tylenchida: Meloidogynidae) are agriculturally important migratory endoparasitic and sedent...
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Screening of reference genes in real-time PCR for Radopholus similis.
PeerJ, 2019Co-Authors: Jun-yi Li, Wan-zhu Chen, Si-hua Yang, Chun-ling Xu, Xin Huang, Chun ChenAbstract:Six candidate reference genes were chosen from the transcriptome database of Radopholus similis using the bioinformatics method, including four conventional reference genes (actin, Eukaryotic translation initiation factor 5A (eIF5A), Tubulin alpha (a-tubulin), ubiquitin (UBI)) and two new candidate reference genes (Ribosomal protein S21 (Rps21) and Serine/threonine protein phosphatase PP1-β catalytic subunit (β-PP1)). In addition, a traditional reference gene 18S ribosomal RNA (18S rRNA) obtained from NCBI databases was also added to the analysis. Real-time PCR was used to detect the expression of seven candidate reference genes in six populations of R. similis and four developmental stages (female, male, larva and egg) of a population. The stability of the expression of candidate genes was evaluated by three software programs, BestKeeper, geNorm and NormFinder. The results showed that eIF5A is the most suitable reference gene for gene functional research of different populations, while both Rps21 and eIF5A are the most suitable reference genes for different developmental stages of a population. Therefore, eIF5A is the best reference gene for studying R. similis. However, one defect of this study is that only seven candidate reference genes were analyzed; ideally, more genes should be tested.
Jun-yi Li - One of the best experts on this subject based on the ideXlab platform.
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Screening of reference genes in real-time PCR for Radopholus similis.
PeerJ, 2019Co-Authors: Jun-yi Li, Wan-zhu Chen, Si-hua Yang, Chun-ling Xu, Xin Huang, Chun ChenAbstract:Six candidate reference genes were chosen from the transcriptome database of Radopholus similis using the bioinformatics method, including four conventional reference genes (actin, Eukaryotic translation initiation factor 5A (eIF5A), Tubulin alpha (a-tubulin), ubiquitin (UBI)) and two new candidate reference genes (Ribosomal protein S21 (Rps21) and Serine/threonine protein phosphatase PP1-β catalytic subunit (β-PP1)). In addition, a traditional reference gene 18S ribosomal RNA (18S rRNA) obtained from NCBI databases was also added to the analysis. Real-time PCR was used to detect the expression of seven candidate reference genes in six populations of R. similis and four developmental stages (female, male, larva and egg) of a population. The stability of the expression of candidate genes was evaluated by three software programs, BestKeeper, geNorm and NormFinder. The results showed that eIF5A is the most suitable reference gene for gene functional research of different populations, while both Rps21 and eIF5A are the most suitable reference genes for different developmental stages of a population. Therefore, eIF5A is the best reference gene for studying R. similis. However, one defect of this study is that only seven candidate reference genes were analyzed; ideally, more genes should be tested.