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Vivian C. Blok - One of the best experts on this subject based on the ideXlab platform.
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Influence of soil temperature on Globodera rostochiensis and Globodera pallida
Phytopathologia Mediterranea, 2014Co-Authors: Agata Kaczmarek, Katrin Mackenzie, Helen Kettle, Vivian C. BlokAbstract:Relationships between soil temperatures and the potato cyst nematode (PCN) life cycle and population multiplication were investigated to understand the risks to potato crops from PCN in relation to increasing soil temperatures associated with climate change, and to support development of the United Kingdom Potato Council`s PCN management model. The initial (hatching) part of the PCN life cycle was examined for both Globodera rostochiensis and G. pallida over a range of temperatures, and the responses are then considered in relation to actual soil temperatures during the potato growing season in different sites in the United Kingdom. Hatching was stimulated by potato root diffusate over a temperature range from 5–29oC and was monitored for 5 weeks. The greatest cumulative percentage hatch of second stage juveniles (J2) occurred between 15 and 27oC for G. rostochiensis and 13–25oC for G. pallida. Globodera rostochiensis hatched more quickly and had a delayed hatch at ≥25oC while G. pallida was more efficient at these higher temperatures. From these observations, it is likely that climate change, and associated increases in soil temperatures, will result in increased rates and amounts of hatching for both species, leading to increased population levels on susceptible hosts and damage to potato crops. Currently, regions of the United Kingdom with warm soil temperatures are also expected to have high levels of hatching of PCN, and therefore greater multiplication resulting in greater challenges in the management of these nematodes in infested land.
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Comparison of transcript profiles in different life stages of the nematode Globodera pallida under different host potato genotypes
Molecular plant pathology, 2012Co-Authors: Juan E. Palomares-rius, Pete E. Hedley, Peter J. A. Cock, Jenny Morris, John T. Jones, Nikos Vovlas, Vivian C. BlokAbstract:Summary The potato cyst nematodes (PCNs) Globodera pallida and Globodera rostochiensis are important parasites of potato. PCNs undergo complex biotrophic interactions with their hosts that involve gene expression changes in both the nematode and the host plant. The aim of this study was to determine key genes that are differentially expressed in Globodera pallida life cycle stages and during the initiation of the feeding site in susceptible and partially resistant potato genotypes. For this purpose, two microarray experiments were designed: (i) a comparison of eggs, infective second-stage juveniles (J2s) and sedentary parasitic-stage J2s (SJ2); (ii) a comparison of SJ2s at 8 days after inoculation (DAI) in the susceptible cultivar (Desiree) and two partially resistant lines. The results showed differential expression of G. pallida genes during the stages studied, including previously characterized effectors. In addition, a large number of genes changed their expression between SJ2s in the susceptible cultivar and those infecting partially resistant lines; the number of genes with modified expression was lower when the two partially resistant lines were compared. Moreover, a histopathological study was performed at several time points (7, 14 and 30 DAI) and showed the similarities between both partially resistant lines with a delay and degeneration in the formation of the syncytia in comparison with the susceptible cultivar. Females at 30 DAI in partially resistant lines showed a delay in their development in comparison with those in the susceptible cultivar.
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Poly(T) Variation Within Mitochondrial Protein-Coding Genes in Globodera (Nematoda: Heteroderidae)
Journal of Molecular Evolution, 2008Co-Authors: Angelique H. Riepsamen, Vivian C. Blok, Tracey Gibson, Mark Phillips, Mark DowtonAbstract:We sequenced a mitochondrial subgenome from the nematode Globodera rostochiensis , in two overlapping pieces. The subgenome was 9210 bp and contained four protein-coding genes ( ND4 , COIII , ND3 , Cytb ) and two tRNA genes ( tRNA ^ Thr , tRNA ^ Gln ). Genome organization was similar to that of Globodera pallida , which is multipartite. Together with the small number of genes on this subgenome, this suggests that the mitochondrial genome of G. rostochiensis is also multipartite. In the initial clones sequenced, COIII and ND3 were full-length, while ND4 and Cytb were interrupted by premature stop codons and contained point indels that disrupted the reading frame. However, sequencing of multiple clones, from DNA extracted both from multiple individuals and from single cysts, revealed a predominant source of variation—in the length of polythymidine tracts. Comparison of our genomic sequences with ESTs similarly revealed variation in the length of polythymidine tracts. We subsequently sequenced both genomic DNA and mRNA from populations of G. pallida . In each case, variation in the length of polythymidine tracts was observed. The levels of expression of mitochondrial genes in G. pallida were representative of the subgenomes present: little evidence of differential expression was observed. These observations are consistent with the operation of posttranscriptional editing in Globodera mitochondria, although this is difficult to show conclusively in the presence of intraindividual gene sequence variation. Further, alternative explanations cannot be discounted; these include the operation of slippage during translation or that genomic copies of most genes are pseudogenes with a small proportion of full-length sequences able to maintain mitochondrial function.
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Molecular variation in the potato cyst nematode, Globodera pallida, in relation to virulence.
Communications in agricultural and applied biological sciences, 2006Co-Authors: Vivian C. Blok, L. A. Pylypenko, Mark S. PhillipsAbstract:The potato cyst nematode Globodera pallida poses a challenge for potato growers. The potato cyst nematodes (PCN) Globodera rostochiensis and G. pallida cause damage valued at over pounds 50m per annum in the U.K. and problems in controlling PCN are growing due to the increase in populations and spread of G. pallida, the lack of many commercially attractive cultivars with resistance to this species and the pressure to reduce nematicide use. Over 60% of potato fields in the U.K. are infected with G. pallida (Minnis et al. 2000). The Scottish Agricultural Science Agency (SASA) figures show that the incidence of both species of PCN on Scottish seed potato land, though low, has been increasing. The proportion of potato land in ware production in Scotland is also increasing and now represents 50% of the potato growing area. This situation potentially increases the risk of the spread of PCN unless it is very carefully monitored and managed.
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Investigation of resistance specificity amongst fifteen wild Solanum species to a range of Globodera pallida and G. rostochiensis populations
Nematology, 2005Co-Authors: Lydia M. Castelli, Glenn J. Bryan, Vivian C. Blok, Gavin Ramsay, Mark S. PhillipsAbstract:The breadth of resistance to populations of the potato cyst nematodes, Globodera pallida and G. rostochiensis, which differed both in virulence level and country of origin, was investigated in 15 wild Solanum species. A range of responses to the populations was noted, with significant interactions observed between the potato genotypes and Globodera populations assayed. Of the 15 wild Solanum species, seven appeared to be potentially valuable sources of wide spectrum resistance with low multiplication rates with all populations recorded. The inclusion of these species into a potato breeding programme is justified by this study.
Mark Dowton - One of the best experts on this subject based on the ideXlab platform.
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Poly(T) Variation Within Mitochondrial Protein-Coding Genes in Globodera (Nematoda: Heteroderidae)
Journal of Molecular Evolution, 2008Co-Authors: Angelique H. Riepsamen, Vivian C. Blok, Tracey Gibson, Mark Phillips, Mark DowtonAbstract:We sequenced a mitochondrial subgenome from the nematode Globodera rostochiensis , in two overlapping pieces. The subgenome was 9210 bp and contained four protein-coding genes ( ND4 , COIII , ND3 , Cytb ) and two tRNA genes ( tRNA ^ Thr , tRNA ^ Gln ). Genome organization was similar to that of Globodera pallida , which is multipartite. Together with the small number of genes on this subgenome, this suggests that the mitochondrial genome of G. rostochiensis is also multipartite. In the initial clones sequenced, COIII and ND3 were full-length, while ND4 and Cytb were interrupted by premature stop codons and contained point indels that disrupted the reading frame. However, sequencing of multiple clones, from DNA extracted both from multiple individuals and from single cysts, revealed a predominant source of variation—in the length of polythymidine tracts. Comparison of our genomic sequences with ESTs similarly revealed variation in the length of polythymidine tracts. We subsequently sequenced both genomic DNA and mRNA from populations of G. pallida . In each case, variation in the length of polythymidine tracts was observed. The levels of expression of mitochondrial genes in G. pallida were representative of the subgenomes present: little evidence of differential expression was observed. These observations are consistent with the operation of posttranscriptional editing in Globodera mitochondria, although this is difficult to show conclusively in the presence of intraindividual gene sequence variation. Further, alternative explanations cannot be discounted; these include the operation of slippage during translation or that genomic copies of most genes are pseudogenes with a small proportion of full-length sequences able to maintain mitochondrial function.
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sequence and characterization of six mitochondrial subgenomes from Globodera rostochiensis multipartite structure is conserved among close nematode relatives
Journal of Molecular Evolution, 2007Co-Authors: Tracey Gibson, A Vivian E C Blok, Mark DowtonAbstract:Recently, a multipartite mitochondrial genome was characterized in the potato cyst nematode, Globodera pallida. Six subgenomic circles were detectable by PCR, while full-length genomes were not. We investigate here whether this subgenomic organization occurs in a close relative of G. pallida. We amplified and sequenced one entire mitochondrial subgenome from the cyst-forming nematode, Globodera rostochiensis. Comparison of the noncoding region of this subgenome with those reported previously for G. pallida facilitated the design of amplification primers for a range of subgenomes from G. rostochiensis. We then randomly sequenced five subgenomic fragments, each representative of a unique subgenome. This study indicates that the multipartite structure reported for G. pallida is conserved in G. rostochiensis. A comparison of subgenomic organization between these two Globodera species indicates a considerable degree of overlap between them. Indeed, we identify two subgenomes with an organization identical with that reported for G. pallida. However, other subgenomes are unique to G. rostochiensis, although some of these have blocks of genes comparable to those in G. pallida. Dot-plot comparisons of pairs of subgenomes from G. rostochiensis indicate that the different subgenomes share fragments with high sequence identity. We interpret this as evidence that recombination is operating in the mitochondria of G. rostochiensis.
Louwrens R. Tiedt - One of the best experts on this subject based on the ideXlab platform.
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Description of Globodera capensis n. sp. (Nematoda: Heteroderidae) from South Africa
Nematology, 2017Co-Authors: R. Knoetze, Antoinette Swart, Louwrens R. TiedtAbstract:A new cyst nematode, herein described as Globodera sandveldensis n. sp., was found in the Sandveld, Western Cape Province, South Africa. As the host plant of G. sandveldensis n. sp. is currently unknown, the species is represented by cysts and second-stage juveniles (J2) only. The J2 are characterised by a well developed stylet of 26.4 (24.8-28.5) μ m with rounded to anteriorly flattened knobs. The distance from the dorsal pharyngeal gland outlet to the stylet knobs is 4.5 (2.4-7.2) μ m. The tail is 64 (56-77) μ m long and the length of the hyaline region is 33 (22-39) μ m. The cysts are characterised by their ovate to spherical shape, short neck, and the presence of subcuticular punctations and bullae or vulval bodies. Six to 14 cuticular ridges/lines are present on the outer surface of the cyst between the anus and vulval basin. Granek’s ratio is 1.7 (0.9-3.0), the vulval basin diam. is 20.4 (13.1-34.6) μ m and the distance between vulval basin and anus is 33.5 (19.7-54.0) μ m. Phylogenetic relationships with other species of the genus, inferred from ITS-rDNA sequences, indicate that G. sandveldensis n. sp. is included in the clade of Globodera sp. that parasitise non-solanaceous plants and is closely related to unidentified Globodera spp. from Portugal, G. millefolii , and G. artemisiae .
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A new Globodera cyst nematode from South Africa (Tylenchida: Heteroderidae)
Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, 2013Co-Authors: A. Swart, R. Knoetze, Louwrens R. TiedtAbstract:A new Globodera cyst nematode from South Africa (Tylenchida: Heteroderidae). Nematode cysts were collected during a survey of potato fields in the Sandveld area of South Africa. Morphological and molecular analysis of these cysts confirmed the presence of the golden cyst nematode (Globoderarostochiensis), as well as an unknown Globodera species. Although morphologically indistinguishable, molecular and hatching studies showed that the two Globodera species are not conspecific.
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Description of Globodera capensis n. sp. (Nematoda: Heteroderidae) from South Africa.
Nematology, 2013Co-Authors: R. Knoetze, Antoinette Swart, Louwrens R. TiedtAbstract:A new cyst nematode, herein described as Globodera capensis n. sp., was found on several farms in the Swartland and Sandveld areas in South Africa. As the host plant of G. capensis n. sp. is currently unknown, the species is represented by cysts and second-stage juveniles (J2) only. The cysts have a spherical form, are yellow to dark brown in colour and have bullae (vulval bodies) and subcuticular punctations. Six to 20 cuticular ridges/lines are present between the anus and vulval basin, Granek’s ratio is 0.7-4.0, the vulval basin diam. is 16-28.5 μm and vulval basin to anus distance is 19-60 μm. The J2 is 430-528 μm long and the stylet is 23-28 μm long with anteriorly flattened to rounded stylet knobs. These stages are morphologically and morphometrically very near to, or indistinguishable from PCN, G. artemisiae, G. millefolii and G. tabacum tabacum. It can be distinguished by the molecular characteristics of the ITS-region of the ribosomal DNA. Pairwise distances between closely related Globodera species show that G. capensis n. sp. differs the least in number of base differences per sequence from G. millefolii (63-64 bp) and most from an undescribed Globodera from Chile (72-73 bp). Phylogenetic relationships of G. capensis n. sp. with selected species of Punctoderinae, inferred from ITS-rRNA sequences by using the Maximum Likelihood method, indicate that G. capensis n. sp. occupies a basal position within a lineage of Globodera species from Europe, Asia and New Zealand that parasitises non-solanaceous plants. For diagnostic purposes, digestion of the ITS1 with AluI will distinguish G. capensis n. sp. from G. mexicana, G. pallida, G. rostochiensis and G. tabacum, but not from G. artemisiae, G. millefolii and G. zelandica, whilst FauI will distinguish G. capensis n. sp. from all the other Globodera species tested.
John T. Jones - One of the best experts on this subject based on the ideXlab platform.
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Comparison of transcript profiles in different life stages of the nematode Globodera pallida under different host potato genotypes
Molecular plant pathology, 2012Co-Authors: Juan E. Palomares-rius, Pete E. Hedley, Peter J. A. Cock, Jenny Morris, John T. Jones, Nikos Vovlas, Vivian C. BlokAbstract:Summary The potato cyst nematodes (PCNs) Globodera pallida and Globodera rostochiensis are important parasites of potato. PCNs undergo complex biotrophic interactions with their hosts that involve gene expression changes in both the nematode and the host plant. The aim of this study was to determine key genes that are differentially expressed in Globodera pallida life cycle stages and during the initiation of the feeding site in susceptible and partially resistant potato genotypes. For this purpose, two microarray experiments were designed: (i) a comparison of eggs, infective second-stage juveniles (J2s) and sedentary parasitic-stage J2s (SJ2); (ii) a comparison of SJ2s at 8 days after inoculation (DAI) in the susceptible cultivar (Desiree) and two partially resistant lines. The results showed differential expression of G. pallida genes during the stages studied, including previously characterized effectors. In addition, a large number of genes changed their expression between SJ2s in the susceptible cultivar and those infecting partially resistant lines; the number of genes with modified expression was lower when the two partially resistant lines were compared. Moreover, a histopathological study was performed at several time points (7, 14 and 30 DAI) and showed the similarities between both partially resistant lines with a delay and degeneration in the formation of the syncytia in comparison with the susceptible cultivar. Females at 30 DAI in partially resistant lines showed a delay in their development in comparison with those in the susceptible cultivar.
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sxp ral 2 proteins of the potato cyst nematode Globodera rostochiensis secreted proteins of the hypodermis and amphids
Nematology, 2000Co-Authors: John T. Jones, G Smant, Vivian C. BlokAbstract:A family of secreted proteins (the SXP/ RAL-2 proteins) has been identified in animal parasitic nematodes and Caenorhabditis elegans . In this paper, we describe two full length cDNA sequences from the potato cyst nematode Globodera rostochiensis which could encode proteins similar to SXP/ RAL-2 proteins. We show that although both genes are expressed in second stage juveniles and in sedentary females of G. rostochiensis , they have remarkably different spatial expression patterns. The mRNA derived from one of the genes ( gr-sxp-1 ) was present in the hypodermis, as has been described previously for one of these genes in an animal parasitic nematode. However, expression of the mRNA from the other gene was restricted to the gland cells surrounding the amphidial sense organs (the sheath cells). In addition to providing the first description of SXP proteins from a plant parasitic nematode, this work provides the first detailed characterisation of a protein secreted from the amphids of a plant parasite. Les proteines SXP/ RAL-2 du nematode a kyste de la pomme de terre Globodera rostochiensis : les proteines secretees par l'hypoderme et les amphides - Une famille de proteines secretees - les proteines SXP/ RAL-2 - avait deja ete identifiee chez les nematodes zooparasites et chez Caenorhabditis elegans . Dans cet article nous decrivons deux sequences en longueur totale de cADN provenant du nematode a kyste de la pomme de terre Globodera rostochiensis , sequences qui pourraient coder des proteines similaires aux proteines SXP/ RAL-2 . Nous montrons que, bien que l'un et l'autre gene s'expriment chez les juveniles de deuxieme stade et chez les femelles sedentaires de Globodera rostochiensis , ils possedent des profils d'expression spatiale remarquablement differents. Le rARN derive a partir d'un de ces genes ( gr-sxp-1 ) etait present dants l'hypoderme, comme cela avait deja ete decrit pour l'un de ces genes chez un nematode zooparasite. Cependant, l'expression du mRNA de l'autre gene etait limitee aux cellules glandulaires entourant les organes sensoriels amphidiens (les cellules de la gaine). Offrant la premiere description de proteines SXP provenant de nematodes phytopathogenes, le present travail fournit de plus la premiere caracterisation detaillee d'une proteine secretee par les amphides d'un nematode parasite de plantes.
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SXP/RAL-2 proteins of the potato cyst nematode Globodera rostochiensis: secreted proteins of the hypodermis and amphids
Nematology, 2000Co-Authors: John T. Jones, G Smant, Vivian C. BlokAbstract:A family of secreted proteins (the SXP/ RAL-2 proteins) has been identified in animal parasitic nematodes and Caenorhabditis elegans . In this paper, we describe two full length cDNA sequences from the potato cyst nematode Globodera rostochiensis which could encode proteins similar to SXP/ RAL-2 proteins. We show that although both genes are expressed in second stage juveniles and in sedentary females of G. rostochiensis , they have remarkably different spatial expression patterns. The mRNA derived from one of the genes ( gr-sxp-1 ) was present in the hypodermis, as has been described previously for one of these genes in an animal parasitic nematode. However, expression of the mRNA from the other gene was restricted to the gland cells surrounding the amphidial sense organs (the sheath cells). In addition to providing the first description of SXP proteins from a plant parasitic nematode, this work provides the first detailed characterisation of a protein secreted from the amphids of a plant parasite. Les proteines SXP/ RAL-2 du nematode a kyste de la pomme de terre Globodera rostochiensis : les proteines secretees par l'hypoderme et les amphides - Une famille de proteines secretees - les proteines SXP/ RAL-2 - avait deja ete identifiee chez les nematodes zooparasites et chez Caenorhabditis elegans . Dans cet article nous decrivons deux sequences en longueur totale de cADN provenant du nematode a kyste de la pomme de terre Globodera rostochiensis , sequences qui pourraient coder des proteines similaires aux proteines SXP/ RAL-2 . Nous montrons que, bien que l'un et l'autre gene s'expriment chez les juveniles de deuxieme stade et chez les femelles sedentaires de Globodera rostochiensis , ils possedent des profils d'expression spatiale remarquablement differents. Le rARN derive a partir d'un de ces genes ( gr-sxp-1 ) etait present dants l'hypoderme, comme cela avait deja ete decrit pour l'un de ces genes chez un nematode zooparasite. Cependant, l'expression du mRNA de l'autre gene etait limitee aux cellules glandulaires entourant les organes sensoriels amphidiens (les cellules de la gaine). Offrant la premiere description de proteines SXP provenant de nematodes phytopathogenes, le present travail fournit de plus la premiere caracterisation detaillee d'une proteine secretee par les amphides d'un nematode parasite de plantes.
R. Knoetze - One of the best experts on this subject based on the ideXlab platform.
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DNA barcoding, phylogeny and phylogeography of the cyst nematode species from the genus Globodera (Tylenchida: Heteroderidae)
Nematology, 2020Co-Authors: Sergei A. Subbotin, Javier Franco, R. Knoetze, Tatiana V. Roubtsova, Richard M. Bostock, Ignacio Cid Del Prado VeraAbstract:Globodera presently contains 13 valid and three as yet undescribed species. Three species, G. rostochiensis, G. pallida and G. ellingtonae, the potato cyst nematodes (PCN), cause significant economic losses on potatoes around the world. In our study we provide comprehensive phylogenetic analyses of 455 ITS rRNA, 219 COI and 164 cytb gene sequences of 11 valid and two undescribed species of Globodera using Bayesian inference, maximum likelihood and statistical parsimony. New 205 COI, 116 cytb and 21 ITS rRNA gene sequences were obtained from 148 populations of these species collected from 23 countries. The phylogenetic analysis revealed that Globodera displayed two main clades in the trees: i) Globodera from South and North America parasitising plants from Solanaceae; and ii) Globodera from Africa, Europe, Asia and New Zealand parasitising plants from Asteraceae and other families. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it is hypothesised that Globodera species originated and diversified from several centres of speciation located in mountain regions and then dispersed across the world from these regions during the Pleistocene. High genetic diversity of Bolivian populations of G. rostochiensis was observed for both mtDNA genes. Analysis of phylogenetic relationships of G. pallida and G. rostochiensis populations revealed incongruence in topology between networks inferred from mtDNA genes, which might be an indication of possible recombination and selective introgression events through gene flow between previously isolated populations. This puts some limitations on the use of the mtDNA marker as universal DNA barcoding identifier for PCN. Globodera bravoae syn. n. is proposed as a junior synonym of G. mexicana.
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Description of Globodera capensis n. sp. (Nematoda: Heteroderidae) from South Africa
Nematology, 2017Co-Authors: R. Knoetze, Antoinette Swart, Louwrens R. TiedtAbstract:A new cyst nematode, herein described as Globodera sandveldensis n. sp., was found in the Sandveld, Western Cape Province, South Africa. As the host plant of G. sandveldensis n. sp. is currently unknown, the species is represented by cysts and second-stage juveniles (J2) only. The J2 are characterised by a well developed stylet of 26.4 (24.8-28.5) μ m with rounded to anteriorly flattened knobs. The distance from the dorsal pharyngeal gland outlet to the stylet knobs is 4.5 (2.4-7.2) μ m. The tail is 64 (56-77) μ m long and the length of the hyaline region is 33 (22-39) μ m. The cysts are characterised by their ovate to spherical shape, short neck, and the presence of subcuticular punctations and bullae or vulval bodies. Six to 14 cuticular ridges/lines are present on the outer surface of the cyst between the anus and vulval basin. Granek’s ratio is 1.7 (0.9-3.0), the vulval basin diam. is 20.4 (13.1-34.6) μ m and the distance between vulval basin and anus is 33.5 (19.7-54.0) μ m. Phylogenetic relationships with other species of the genus, inferred from ITS-rDNA sequences, indicate that G. sandveldensis n. sp. is included in the clade of Globodera sp. that parasitise non-solanaceous plants and is closely related to unidentified Globodera spp. from Portugal, G. millefolii , and G. artemisiae .
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A new Globodera cyst nematode from South Africa (Tylenchida: Heteroderidae)
Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie, 2013Co-Authors: A. Swart, R. Knoetze, Louwrens R. TiedtAbstract:A new Globodera cyst nematode from South Africa (Tylenchida: Heteroderidae). Nematode cysts were collected during a survey of potato fields in the Sandveld area of South Africa. Morphological and molecular analysis of these cysts confirmed the presence of the golden cyst nematode (Globoderarostochiensis), as well as an unknown Globodera species. Although morphologically indistinguishable, molecular and hatching studies showed that the two Globodera species are not conspecific.
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Description of Globodera capensis n. sp. (Nematoda: Heteroderidae) from South Africa.
Nematology, 2013Co-Authors: R. Knoetze, Antoinette Swart, Louwrens R. TiedtAbstract:A new cyst nematode, herein described as Globodera capensis n. sp., was found on several farms in the Swartland and Sandveld areas in South Africa. As the host plant of G. capensis n. sp. is currently unknown, the species is represented by cysts and second-stage juveniles (J2) only. The cysts have a spherical form, are yellow to dark brown in colour and have bullae (vulval bodies) and subcuticular punctations. Six to 20 cuticular ridges/lines are present between the anus and vulval basin, Granek’s ratio is 0.7-4.0, the vulval basin diam. is 16-28.5 μm and vulval basin to anus distance is 19-60 μm. The J2 is 430-528 μm long and the stylet is 23-28 μm long with anteriorly flattened to rounded stylet knobs. These stages are morphologically and morphometrically very near to, or indistinguishable from PCN, G. artemisiae, G. millefolii and G. tabacum tabacum. It can be distinguished by the molecular characteristics of the ITS-region of the ribosomal DNA. Pairwise distances between closely related Globodera species show that G. capensis n. sp. differs the least in number of base differences per sequence from G. millefolii (63-64 bp) and most from an undescribed Globodera from Chile (72-73 bp). Phylogenetic relationships of G. capensis n. sp. with selected species of Punctoderinae, inferred from ITS-rRNA sequences by using the Maximum Likelihood method, indicate that G. capensis n. sp. occupies a basal position within a lineage of Globodera species from Europe, Asia and New Zealand that parasitises non-solanaceous plants. For diagnostic purposes, digestion of the ITS1 with AluI will distinguish G. capensis n. sp. from G. mexicana, G. pallida, G. rostochiensis and G. tabacum, but not from G. artemisiae, G. millefolii and G. zelandica, whilst FauI will distinguish G. capensis n. sp. from all the other Globodera species tested.