Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Disparate gain and loss of parasitic abilities among nematode lineages
Holterman, Martijn ; Karegar, Akbar ; Mooijman, Paul ; Megen, Hanny van; Elsen, Sven van den; Vervoort, M.T.W. ; Quist, Casper W. ; Karssen, Gerrit ; Decraemer, Wilfrida ; Opperman, Charles H. ; Bird, David M. ; Kammenga, Jan ; Goverse, Aska ; Smant, Geert ; Helder, Hans - \ 2017
PLoS ONE 12 (2017)9. - ISSN 1932-6203 - 18 p.

Plant parasitism has arisen time and again in multiple phyla, including bacteria, fungi, insects and nematodes. In most of these organismal groups, the overwhelming diversity hampers a robust reconstruction of the origins and diversification patterns of this trophic lifestyle. Being a moderately diversified phylum with ≈ 4,100 plant parasites (15% of total biodiversity) subdivided over four independent lineages, nematodes constitute a major organismal group for which the genesis of plant parasitism could be mapped. Since substantial crop losses worldwide have been attributed to less than 1% of these plant parasites, research efforts are severely biased towards this minority. With the first molecular characterisation of numerous basal and supposedly harmless plant parasites as well as their non-parasitic relatives, we were able to generate a comprehensive molecular framework that allows for the reconstruction of trophic diversification for a complete phylum. In each lineage plant parasites reside in a single taxonomic grouping (family or order), and by taking the coverage of the next lower taxonomic level as a measure for representation, 50, 67, 100 and 85% of the known diversity was included. We revealed distinct gain and loss patterns with regard to plant parasitism per se as well as host exploitation strategies between these lineages. Our map of parasitic nematode biodiversity also revealed an unanticipated time reversal in which the two most ancient lineages showed the lowest level of ecological diversification and vice versa.

Broad phylogenetic analyses of the four major plant-parasitic nematode lineages reveal essentially distinct origins and diversification patterns
Holterman, M.H.M. ; Karegar, A. ; Mooijman, P.J.W. ; Decreamer, W. ; Elsen, S.J.J. van den; Vervoort, M.T.W. ; Quist, C.W. ; Karssen, G. ; Opperman, Charles H. ; Bird, David M. ; Smant, G. ; Helder, J. - \ 2016
evolution sedentary endoparasitism, phoresy, SSU ribosomal DNA, virus transmission
Four major nematode clades are discerned within which plant parasitism arose at least once. The distinct levels of diversification within the individual clades are reflected by their systematics: plant parasites in the basal Clades 1 and 2 reside in (just) two families (Trichodoridae and Longidoridae). Meanwhile, in Clades 10 and 12 parasitic nematodes are allocated in a superfamily (Aphelenchoidoidea) and an order (Tylenchida). By taking the coverage of the next lower taxonomic level as a measure, 60, 80, 100 and 85% of the diversity was included in our phylogenetic analyses. Individual clades represented by 93 (Clade 1), 171 (Clade 2), 320 (Clade 10), and 1,089 (Clade 12) nearly full-length small subunit ribosomal DNA sequences (≈ 1,700 bp each) were analyzed using Bayesian and Maximum likelihood-based inferences. Diversification patterns among these Clades are distinct. Clades 1 and 2 exclusively harbor ectoparasites, of which a subset transmits Tobra (Trichodoridae) or Nepo-viruses (Longidoridae). Superposition of current virus-transmission data on phylogenetic trees revealed 3 (Trichodoridae) and > 5 clusters (Longidoridae) suggesting that minor modifications in the virus-pharynx interface suffice to acquire this capability. Endoparasitism arose exclusively in Clades 10 and 12, resulting in disparate life strategies in each of these clades. Plant parasitism within Clade 10 arose at least 4 times from insect-vectored fungivorous lineages (occasionally with secondary loss of the insect association) and resulted almost exclusively in endoparasites of above-ground plant parts, in the absence of (intermediate) ectoparasites. Our analyses point at a single common origin of all predominantly below-ground feeding plant parasites in Clade 12, whereas sedentary endoparasitism arose at least five times. Numerous origins and shapes of plant parasitism-relevant characteristics such as the development of plant parasitism per se, of sedentary endoparasitism, and of virus-vectoring capacities point at an unexpected flexibility within this morphologically conserved phylum.
Plant-feeding nematodes in coastal sand dunes: occurrence, host specificity and effects on plant growth
Brinkman, E.P. ; Duyts, H. ; Karssen, G. ; Stoel, C.D. ; Putten, W.H. van der - \ 2015
Plant and Soil 397 (2015)1. - ISSN 0032-079X - p. 17 - 30.
Ammophila arenaria - Ectoparasite - Endoparasite - Foredune - Generalist - Specialist
Aims Coastal sand dunes have a well-established abiotic gradient from beach to land and a corresponding spatial gradient of plant species representing succession in time. Here, we relate the distribution of plant-feeding nematodes with dominant plant species in the field to host specialization and impacts on plant species under controlled greenhouse conditions. Methods We assessed plant-feeding nematodes in soil and roots of six plant species that dominate the vegetation at successional positions along the gradient. In controlled conditions, we determined performance of all plant-feeding nematodes on each plant species and their effects on plant biomass. Results Specialist feeding type nematodes were confined to plant species in either foredunes or landward dunes. Generalist feeding type nematodes were found in highest numbers in the landward dunes. Most tested nematode species decreased root, but not shoot or rhizome biomass. Conclusions Host plant suitability determined occurrence of some plant-feeding nematodes in dunes, but abiotic and biotic soil conditions may play a role as well. Generalist feeding type nematodes were able to reproduce on all plant species. Feeding specialists, which are more protected by plant roots, might prefer host plants in the foredunes for the same reason as their host plants: to escape from natural enemies.
The identity and reproduction potential of South African Meloidogyne species
Fouri, A.M.H. ; Mienie, C.M. ; Marais, M. ; Daneel, M. ; Karssen, G. - \ 2015
In: Proceedings of 54th Annual Meeting of the Society of Nematologists. - - p. 95 - 95.
Root-­-knot nematodes, Meloidogyne spp., generally are the economically most important nematode pests that parasitise agri-­- and horticultural crops in South Africa. The aims of the study were to i) identify Meloidogyne spp. individuals that infect roots/tubers/pods of crop plants received for diagnostic analyses and from research sites across South Africa using molecular and morphological identification techniques and ii) determine the reproductive potential of Meloidogyne species populations identified during the study in a greenhouse experiment (randomised complete block design with six replicates). Deoxyribonucleic acid (DNA) was extracted from mature females obtained from infected, below-­-ground parts of crops and subjected to polymerase chain reaction (PCR) analyses. For the reproduction-­- potential study, 1 000 eggs and second-­-stage juveniles (J2) of the respective Meloidogyne spp. populations identified were inoculated on roots of a susceptible tomato cultivar Floradade. Nematode parameters assessed 56 days later included egg-­-laying female indices, egg and J2 numbers and reproduction factors/root system. Meloidogyne incognita and M. javanica proved to be the predominant species that infected maize, potato and soybean crops, while the emerging M. enterolobii (= M. mayaguensis) have also been identified from pepper and guava roots. Other unknown species have also been detected and are currently being identified. The reproduction potential of the various Meloidogyne spp. populations differed substantially within and among species. Positive identification of M. enterolobii, which is easily confused with M. incognita in terms of its morphological identification will contribute towards research aimed at determining the distribution, life cycle and pathogenicity of this pest. This study is ongoing and knowledge generated will benefit the research fraternity as well as producers and ultimately consumers.
Biological and systematic implications of phylogenetic analysis of ~ 2,800 full length small subunit ribosomal DNA sequences
Helder, J. ; Mooijman, P.J.W. ; Elsen, S.J.J. van den; Megen, H.H.B. van; Vervoort, M.T.W. ; Quist, C.W. ; Bert, W. ; Karegar, A. ; Karssen, G. ; Decreamer, W. - \ 2014
In: Proceedings of the 6th International Congress of Nematology. - - p. 26 - 26.
As compared to other ancient and basal Ecdysozoan phyla such as the Nematomorpha (~ 350 known species), the Priapulida (~16 species) and the Kinorhyncha (~180 species), the phylum Nematoda stands out for being speciose (~ 27,000 described species), highly abundant, and widespread in nearly all terrestrial, freshwater and marine habitats. We will present results of phylogenetic analyses of approximately 10% of the described nematode biodiversity (~ 2,800 taxa; with underrepresentation of marine and tropical terrestrial species). We have tried multiple genes for phylogenetic reconstruction but so far the small subunit of the ribosomal DNA (~ 1,700 bp) is the only gene that could easily be amplified and aligned for a wide range of nematode species. The resulting alignment including secondary structure information was analysed on the CIPRES Science Gateway (San Diego, USA), using RAxML, a maximum likelihood-based inference for large phylogenetic trees, and Bayesian inference, and the outcome of both analyses will be presented. Some relevant features of the resulting phylogenetic trees will be discussed, and attention will be paid as to whether or not such a single gene tree does provide us with useful information about organismal relationships. This talk will also be used to describe the positioning and the relationships between the nematode taxa that will be discussed in more detail in Theme 2: Morphology, taxonomy, phylogeny and classification.
250 jaar Copijn in het groen : tentoonstelling 4 april 2014 t/m 1 augustus 2014
Dijkstra, A.G. ; Karssen-Schüürmann, J. - \ 2014
Wageningen : Wageningen UR Library, Speciale Collecties - 43
tuinen - tuinen bij het huis - publieke tuinen - landschapsarchitectuur - geschiedenis - bibliotheken - wetenschappelijke bibliotheken - tentoonstellingen - gardens - domestic gardens - public gardens - landscape architecture - history - libraries - scientific libraries - exhibitions
Twee en een halve eeuw al zijn de leden van de familie Copijn werkzaam in het groen. Een onafgebroken traditie die begon toen Hendrik Copijn zich in 1763 in Groenekan vestigde. Nog steeds is hier Copijn Groenekan boomkwekerij en tuinarchitectuur gevestigd, alsmede ontwerp- en adviesbureau Copijn Bruine Beuk en een paar kilometer ten zuidwesten van Groenekan aan de Gageldijk bevindt zich het bedrijf Copijn Tuin- en Landschapsarchitecten / Boomspecialisten / Groenaanleg en beheer. Deze tentoonstelling is gebaseerd op het boek ‘Met levend materiaal’ : Copijn 1763-2013 tweehonderdvijftig jaar tuinlieden, boomkwekers, boomverzorgers en tuin- en landschapsarchitecten
Meloidogyne luci n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitising different crops in Brazil, Chile and Iran
Carneiro, R.M.D.G. ; Correa, V.R. ; Almeida, M.R.A. ; Gomes, A.C.M.M. ; Deimi, A.M. ; Castagnone-Sereno, P. ; Karssen, G. - \ 2014
Nematology 16 (2014)3. - ISSN 1388-5545 - p. 289 - 301.
additional information - enzyme phenotypes - identification - populations - tylenchida - ethiopica - kiwi
A new root-knot nematode parasitising vegetables, flowers and fruits in Brazil, Iran and Chile, is described as Meloidogyne luci n. sp. The female has an oval to squarish perineal pattern with a low to moderately high dorsal arc and without shoulders, similar to M. ethiopica. The female stylet is robust and 15-16 µm long; the distance from the dorsal pharyngeal gland orifice to the stylet base (DGO) is 3-4 µm. Males have a high, rounded head cap continuous with the body contour. The labial disc is fused with the medial lips to form an elongated lip structure. The head region is not marked by incomplete annulations. Male stylet robust, 20.8-23.0 µm long with rounded knobs; the DGO is 2.5-4.5 µm. The stylet of second-stage juveniles (J2) is 12.0-13.5 µm long and the DGO to the stylet base is 2.3-3.3 µm. The J2 tail is conoid with finely rounded terminus and is 40.0-48.5 µm long. Biochemically, the esterase phenotype L3 (Rm: 1.05, 1.10, 1.25) is unique and is the most useful character to differentiate M. luci n. sp. from all other Meloidogyne species. Reproduction is by mitotic parthenogenesis (2n = 42-46 chromosomes). In a differential host test, the population from Lavandula spica, Caxias do Sul, RS State, Brazil, reproduced on tomato cv. Rutgers, tobacco cv. NC95 and pepper cv. California Wonder. No reproduction occurred on watermelon cv. Charleston Gray, cotton cv. Deltapine 61 or peanut cv. Florunner. In Neighbour-Joining analyses of ITS and D2-D3 rRNA sequences, populations of M. luci n. sp. from Brazil, Chile and Iran clustered together and were clearly separated from other Meloidogyne spp., thus confirming that all three populations are very similar and conspecific.
First report of plant-parasitic nematode Meloidoderita salina in the Netherlands
Ashrafi, S. ; Helder, J. ; Elsen, S.J.J. van den; Jansen, M. ; Karssen, G. - \ 2014
Plant Disease 98 (2014)6. - ISSN 0191-2917 - p. 859 - 859.
After the description of the root-parasitic nematode Meloidoderita salina from a tidal salt marsh in France (1), an additional sampling was carried out to search for the presence of this unusual nematode in a tidal salt marsh area close to Sint-Annaland, province Zeeland in the Netherlands. In August and October 2012, a total of 25 soil and root samples were collected from the halophytic plants Atriplex portulacoides L. (so far the only known host for this nematode species), A. littoralis L., A. prostrata Boucher ex DC., Limonium vulgare Mill., Salicornia europaea L., Aster tripolium L. and Plantago maritima L.. All these halophytes grow in a cohesive muddy soil type within the salt marsh, whereas A. littoralis and A. prostrata grow in the litter tidal zones on the edges of this area. Nematodes from roots and soil were extracted respectively by using centrifugal flotation technique (2) and Oostenbrink’s cotton-wool filter method (4). Additionally roots were used for direct observation of females and young cystoids with a dissecting microscope. Finally all stages were compared morphologically with available type material (1). Examined root and soil samples demonstrated that only nematodes isolated from Atriplex portulacoides, A. littoralis and A. prostrata contained all live stages of the genus Meloidoderita. These soil samples included males, cystoids and second-stage juveniles in low densities ( 99% identity with M. salina sequences from nematodes collected in the afore-mentioned tidal salt marsh in France (FJ969126 and FJ969127). To our knowledge, this is the first report of Meloidoderita salina in the Netherlands. Moreover, this is the first record of M. salina parasitizing Atriplex littoralis and Atriplex prostrata. Although these Atriplex species are used for human consumption, the effect of M. salina on the host is unknown so far.
Both SSU rDNA and RNA polymerase II data recognise that root-knot nematodes arose from migratory Pratylenchidae, but probably not from one of the economically high-impact lesion nematodes
Rybarczyk-Mydlowska, K. ; Megen, H.H.B. van; Elsen, S.J.J. van den; Mooijman, P.J.W. ; Karssen, G. ; Bakker, J. ; Helder, J. - \ 2014
Nematology 16 (2014)2. - ISSN 1388-5545 - p. 125 - 136.
female gonoduct - evolution - phylogeny - n. - tylenchina - framework
In 2000 Siddiqi formulated a hypothesis stating that root-knot nematodes (Meloidogyne spp.) constitute a branch arising from yet another important group of plant parasites, the migratory Pratylenchidae. This hypothesis was solely based on morphological characteristics. Ribosomal DNA (rDNA) sequence analysis supports this hypothesis in its broad sense, but the more precise question about the identity of a migratory Pratylenchidae representative being closest to the most basal Meloidogyne species could not be addressed due to a lack of backbone resolution (Holterman et al., 2009). Here we present an extended small subunit rDNA sequence analysis and a data set of partial RNA polymerase II sequences from Pratylenchidae and basal Meloidogynidae. Our data point at members of the genus Pratylenchus as being closest to the common ancestor of the root-knot nematodes, but it was not possible unequivocally to identify a candidate lesion nematode species. Pratylenchus is a species-rich genus (ca 70 valid species), and we suggest that the species closest to the most basal root-knot nematode should be sought outside of the group of relatively well-characterised, agronomically relevant, species.
On the species status of the root-knot nematode Meloidogyne ulmi Palmisano & Ambrogioni, 2000 (Nematoda, Meloidogynidae)
Ahmed, M. ; Vossenberg, B.T.L.H. van de; Cornelisse, C. ; Karssen, G. - \ 2013
ZooKeys 362 (2013). - ISSN 1313-2989 - p. 1 - 27.
small-subunit rdna - enzyme phenotypes - identification - evolution
The root-knot nematode Meloidogyne ulmi is synonymised with Meloidogyne mali based on morphological and morphometric similarities, common hosts, as well as biochemical similarities at both protein and DNA levels. M. mali was first described in Japan on Malus prunifolia Borkh.; and M. ulmi in Italy on Ulmus chenmoui W.C. Cheng. Morphological and morphometric studies of their holo- and paratypes revealed important similarities in the major characters as well as some general variability in a few others. Host test also showed that besides the two species being able to parasitize the type hosts of the other, they share some other common hosts. Our study of the esterase and malate dehydrogenase isozyme phenotypes of some M. ulmi populations gave a perfectly comparable result to that already known for M. mali. Finally, phylogenetic studies of their SSU and LSU rDNA sequence data revealed that the two are not distinguishable at DNA level. All these put together, leave strong evidences to support the fact that M. ulmi is not a valid species, but a junior synonym of M. mali. Brief discussion on the biology and life cycle of M. mali is given. An overview of all known hosts and the possible distribution of M. mali in Europe are also presented.
Methodology development for partial resistance testing of potato cultivars resistant to M. chitwoodi
Teklu, M.G. ; Been, T.H. ; Schomaker, C.H. - \ 2013
In: Proceedings of the 52nd Annual meeting of Society of nematologist, July 14- 17, 2013, Knoxville, Tennessee, USA. - Knoxville, Tennessee, USA : - p. 106 - 107.
M. chitwoodi was first described in 1995 in The Netherlands (Karssen, 1995). It is now listed as a quarantine organism in the EPPO region with 4 EU member states officially infested. Since 1996, research has been initiated to identify resistant genes against M. chitwoodi from wild species of tuber bearing potatoes and integrate these genes into cultivated potatoes. Currently, several breeding companies successfully produced resistant genotypes against M. chitwoodi. Parallel to this, research was started to develop a standard methodology to screen the partial resistance of these genotypes. Population dynamical models were used to estimate their level of resistance, expressed as percentage of relative susceptibility (rs). This methodology provides farmers with quantitative information on the effect of growing resistant potatoes at any initial population density in their field. The models were first tested in a pilot project in 2010 with 3 resistant potato genotypes in (5 kg) pots at a range of 13 nematode densities. In 2011, another 8 genotypes were tested in (10 kg) pots at a range of 12 densities. The results showed that Seinhorst’s population dynamical models for nematodes with multiple generations fitted well, except in one genotype tested in 2011which lacked resistance to M. chitwoodi, and a reduction of the number of densities used seems possible. In 2012, research was initiated to investigate whether the pot size can be downscaled from 10 to 5 or even to 2 kg pots – also at 12 densities -, without loss of quality of the estimated relative susceptibility. Also, growth, yield loss and quality damage as root knot index (RKI) were assessed and compared. Genotypes 2011M1, MDG2 and cv. Désirée (control) were the tested potatoes. The population dynamical model fitted well for the genotypes tested. The maximum multiplications rate “a” and the maximum population density “M” at 2, 5 and 10 kg pots were estimated and used to calculate the rsa and rsM values . Despite a decrease in “a” and “M” values with increasing pot size the rsa values were relatively stable. The rsM values were a bit higher in 5 kg pots. Seinhorst yield models used to describe the fresh tuber weight also fitted well. The RKI values obtained from the three pots sizes were also stable as a quality measure for industrial processing. Overall results indicate the possibility of downscaling the resistance test for M. chitwoodi in potato in terms of pot size and number of densities. Implications of the current research in the development of a cheap and reliable resistance test will be discussed.
Nematologia Mediterranea (Journal)
Karssen, Gerrit - \ 2013
Nematologia Mediterranea (2013).
Journal of Nematode Morphology and Systematics (Journal)
Karssen, Gerrit - \ 2013
Journal of Nematode Morphology and Systematics (2013).
ZooKeys (Journal)
Karssen, Gerrit - \ 2013
ZooKeys (2013).
Russian Journal of Nematology (Journal)
Karssen, Gerrit - \ 2013
Russian Journal of Nematology (2013).
Redia Giornale di Zoologia (Journal)
Karssen, Gerrit - \ 2013
Redia Giornale di Zoologia (2013).
Root-knot nematodes
Karssen, G. ; Wesemael, W.M.L. ; Moens, M. - \ 2013
In: Plant Nematology / Perry, R.N., Moens, M., Wallingford, UK : CABI (2 ) - ISBN 9781780641515 - p. 73 - 108.
Plant-parasitic nematodes devastate crops worldwide, in turn impacting international trade, social and economic development. Effective control of nematodes is essential for crop protection, and requires an understanding of nematode biology, taxonomy, population dynamics and sampling methods. Providing a broad introduction to nematodes as plant parasites, this book begins by describing nematodes by genera, and builds on this foundation to detail nematode biology and pest management, including biological and chemical control. Chapters are authored by international experts and enhanced by extensive illustrations and focus boxes. Fully updated throughout, this new edition is an essential resource for postgraduate students, extension officers, researchers and crop protection scientists
Editorial: First report of the Root-Knot nematode Meloidogyne artiellia in Belgium
Damme, N. ; Wayenberge, L. ; Viaene, N. ; Hoenselaar, T. van; Karssen, G. - \ 2013
Plant Disease 97 (2013)1. - ISSN 0191-2917 - p. 152 - 152.
Quantitative detection of foliar nematodes (Aphelenchoides ssp.) is complex DNA bachgrounds.
Doorn, J. van; Dees, R.H.L. ; Rybarczyk-Mydlowska, K.D. ; Mooijman, P.J.W. ; Elzen, P.J.M. van den; Vervoort, M. ; Veenhuizen, P.T.M. ; Karssen, G. ; Bakker, J.A. - \ 2012
An overview of the Rothamsted and Wageningen nematode collections, two European collections of international importance
Karssen, Gerrit - \ 2012
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