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Pathotypes of Globodera spp.

A selection of abstracts is given below which relates to the pathotypes of potato cyst nematodes, Globodera rostochiensis and G. pallida, important pests of potatoes. Biochemical and molecular techniques which may be used for the identification and study of different pathotypes have recently become available. These include polymerase chain reaction methods, high performance capillary electrophoresis, random amplified polymorphic DNA and restriction fragment length polymorphsim. Such methods have been used in studies of genetic variation within and between populations of potato cyst nematodes and in studies of resistance mechanisms in potatoes, an important means of controlling Globodera spp.

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TI: Identification of potato cyst nematode species Globodera rostochiensis and G. pallida by PCR using specific primer combinations.
AU: Fullaondo, A.\ Barrena, E.\ Viribay, M.\ Barrena, I.\ Salazar, A.\ Ritter, E.
JN: Nematology
YR: 1999
VL: 1
NO: 2
PP: 157-163
LA: En
LS: fr
MS: 29 ref.
AA: Centro de Investigacion y Mejora Agraria-Granja Modelo, Apartado 46, 01080 Vitoria-Gasteiz, Spain.
AB: RAPD fragments specific for potato cyst nematode (PCN) species G. rostochiensis and G. pallida were identified. These were used to derive two primer combinations for PCR which amplify only one specific band in each species. The primer combinations were evaluated on 39 samples of PCN populations containing all currently described pathotypes as well as some South American PCN populations. This method for species identification is highly sensitive and also allows the detection of species mixtures in a sample. Furthermore, the generation of unique amplification products facilitates the application of automatic detection methods without electrophoretic separation and is therefore particularly useful for routine diagnoses.
DE: identification\plant parasitic nematodes\Globodera rostochiensis\Globodera pallida\Globodera\polymerase chain reaction\amplification\pathotypes\separation\techniques\taxonomy\molecular genetics\detection
AN: 7K02401145

TI: Globodera in potatoes in Russia.
AU: Vasyutin, A. S.\ Yakovleva, V. A.
JN: Kartofel' i Ovoshchi
YR: 1998
NO: No. 6
PP: 29, 32
LA: Ru
AB: Problems with Globodera spp. have been notified from 51 provinces of Russia, on a total area of 41 250 ha. Private holdings show 99% of infestation, while producing a greater proportion of the national potato crop than corporate farms. The nematodes involved are Ro1 pathotypes of Globodera rostochiensis and G. pallida. Potential yield losses in areas of high infestation are 70-80% or even more. The Russian Plant Quarantine Research Institute has developed a range of counter measures, including strict rules on transport of potatoes between infested and clear zones (including imports), crop and field inspections, certification for cleanliness, and movement restrictions on infested holdings backed by Government sanctions for infringements. Chemical control methods are not used. Cultural measures include the use of rotations with non-susceptible crops, the use of organic fertilizers, and the use of resistant cultivars (particularly on private holdings). In 1998, 58 resistance cultivars were available. They were, however, only grown on a small area.
DE: potatoes\Solanum tuberosum\plant parasitic nematodes\Globodera rostochiensis\Globodera pallida\yield losses\nematode control\regulations\transport\imports\chemical control\cultural control\rotations\varietal susceptibility\resistance\organic fertilizers\cultivars\Globodera
GL: Russia
AN: 0T06801319\7K02401128

TI: Virulence of populations of potato cyst nematodes (Globodera spp.) from Europe and Bolivia towards differential potato clones frequently used for pathotype classification.
AU: Bendezu, I. F.\ Russell, M. D.\ Evans, K.
JN: Nematologica
YR: 1998
VL: 44
NO: 6
PP: 667-681
LA: En
LS: de
MS: 24 ref.
AA: IACR-Rothamsted, Harpenden, Herts AL5 2JQ, UK.
AB: European populations of Globodera pallida (10 from the UK, 2 from Iceland, one from the Netherlands) and G. rostochiensis (9 from the UK, 2 from Italy and one each from Germany, Iceland and the Netherlands) and a Bolivian population of the latter species were reared on 3 commercial potato cultivars and 5 differential potato clones. Using Principal Component Analysis and the results of 2 Hierarchical Cluster Analyses, even populations from the same place (e.g. 2 from the same farm at Woburn and 2 from Feltwell) were shown to differ in virulence. Differences were also found between a population selected on potato clone Solanum vernei (VT(n))(2) 62.33.3 and its unselected parent population (Cadishead). Cultivar Morag was partially resistant to G. rostochiensis but showed less resistance to G. pallida than reported previously. The virulence bioassay clearly distinguished the 2 PCN species but failed to classify populations into 'pathotypes'. The arbitrarily designated Pf/Pi value of 1.5 was not necessarily appropriate for distinguishing virulent from avirulent populations. Since virulence appears to be very much a quantitative biological trait (particularly with respect to G. pallida populations), and therefore impossible to classify in a scheme with the logical alternatives of false (does not reproduce) or true (reproduces), its value as a concept probably resides in the future
design of decision making software for forecasting population development based on recorded Pf/Pi values.
DE: Bolivia\Europe\Globodera\Globodera pallida\Globodera rostochiensis\Nematoda\bioassays\forecasting\Germany\Iceland\Italy\Netherlands\computer software\Solanum\Solanum vernei\UK\virulence\plant parasitic nematodes\pest resistance\germplasm\Solanum tuberosum
GL: Bolivia\Europe
AN: 0T06800776\7K02400706

TI: Studies on an artificially fragmented population of potato cyst nematode Globodera pallida.
AU: Phillips, M. S.\ Blok, V. C.\ Ploeg, A.\ Harrower, B. E.
JN: Nematologica
YR: 1998
VL: 44
NO: 6
PP: 655-666
LA: En
LS: de
MS: 24 ref.
AA: Scottish Crop Research Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK.
AB: A series of sub-populations was produced from a population of G. pallida by raising single cyst progenies on 3 susceptible potato cultivars. After completion of each generation, single cysts were taken to produce the next generation. Six generations were completed and then the resulting sub-populations were multiplied on the susceptible cultivar Desiree. A sample of these sub-populations was then used to conduct a virulence test and to investigate the genetic variation among the sub-populations. The virulence test
showed that the susceptible cultivar used in the generation of these sub-populations had a marked effect on the general reproductive capability of the sub-populations and that there was a range of variation in virulence on partially resistant clones. A RAPD study revealed that the range of genetic variation among these sub-populations was comparable to that shown between field populations in other studies and that there was a tendency for the sub-populations to be grouped in relation to the susceptible cultivar they were reared on. These results from an artificially fragmented population are discussed in relation to the introduction and spread of potato cyst nematodes in Europe.
DE: Globodera\Globodera pallida\potatoes\Europe\genetic variation\Nematoda\virulence\plant parasitic nematodes\spread
AN: 0T06800786\7K02400705

TI: Studies on the pathotype of the potato cyst nematode (Globodera rostochiensis) in Nagasaki prefecture.
AU: Aihara, T.\ Sumiya, T.\ Suzuki, K.
JN: Research Bulletin of the Plant Protection Service, Japan
YR: 1998
NO: No. 34
PP: 71-79
LA: Ja
LS: en
MS: 7 ref.
AA: Yokohama Plant Protection Station, Japan.
AB: The occurrence of G. rostochiensis in Nagasaki Prefecture, Japan was recognized in 1992 for the first time. Subsequently, the pathotype of the nematode from a potato field in Minami-arima was tested on a standard differential host (Solanum tuberosum andigena). In addition, the pathotype of the nematode from a potato field in Kazusa was tested on some resistant potato cultivars (resistant to both pathotypes Ro1 and Ro4). The pathotype was identified as Ro1 (the pathotype already known in Hokkaido) by a low population density inoculation test on a non-resistant cultivar.
DE: Globodera rostochiensis\plant parasitic nematodes\Solanum tuberosum\potatoes\races\pathotypes\Japan\identification
GL: Japan
AN: 0T06800326\7K02400186

TI: Variation of virulence, in terms of quantitative reproduction of Globodera pallida populations, from Europe and South America, in relation to resistance from Solanum vernei and S. tuberosum ssp. andigena CPC 2802.
AU: Phillips, M. S.\ Trudgill, D. L.
JN: Nematologica
YR: 1998
VL: 44
NO: 4
PP: 409-423
LA: En
LS: de
MS: 21 ref.
AA: Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA Scotland, UK.
AB: Forty populations of G. pallida originating from either South America or field sites in Europe were tested for their reproductive ability on a susceptible potato cultivar and 5 genotypes with quantitative resistance from either Solanum vernei or S. tuberosum ssp. andigena CPC 2802 in a glasshouse pot experiment. The results showed that there was a wide and continuous range of virulence (85%to 4% reproduction) to all the resistant genotypes. This range was as broad within the European populations as within those from S.America. There was a significant host clone × nematode population interaction, largely accounted for by grouping the clones according to the source of resistance and the populations by their continent of origin. Populations from Europe were relatively more virulent on genotypes derived from S. vernei. In contrast, populations from S. America were relatively more virulent on genotypes derived from S. tuberosum ssp. andigena CPC 2802. Examination of the data from the European populations also showed a significant host × population interaction tending to separate British from mainland European populations.
DE: pathotypes\Globodera pallida\South America\Solanum vernei\virulence\reproduction\Europe\pest resistance\plant parasitic nematodes\potatoes\Solanum tuberosum
AN: 0T06800340\7K02400181\0P06904306

TI: Potato cyst nematodes: species, pathotypes and virulence concepts.
CT: Potato cyst nematodes, biology, distribution and control [edited by Marks, R. J.; Brodie, B. B.].
AU: Fleming, C. C.\ Powers, T. O.
YR: 1998
PP: 51-57
BN: ISBN 0-85199-274-9
LA: En
MS: 35 ref.
AA: Department of Agriculture for Northern Ireland and the Queen's University of Belfast, Applied Plant Science Division, Agriculture and Food Science Centre, Newforge Lane, Belfast BT9 5PX, UK.
DE: Globodera pallida\Globodera rostochiensis\potatoes\books\plant
parasitic nematodes\pathotypes\virulence
AN: 7K02301634\0T06800333

TI: Distribution and virulence of Globodera pallida (Nematoda: Heteroderidae) in Bulgaria.
AU: Samaliev, Kh.
JN: Rasteniev"dni Nauki
YR: 1998
VL: 35
NO: 1
PP: 66-69
LA: Bg
LS: en
MS: 9 ref.
AA: Higher Agricultural Institute, Plovdiv, Bulgaria.
AB: The distribution and pathogenicity of G. pallida in 5 potato growing regions in Bulgaria were determined using differential potato species. G. pallida (Pa(3)) in a mixed population with G. rostochiensis, was identified in only 3 farms in 2 of the regions.
DE: Bulgaria\Globodera pallida\Globodera\virulence\Globodera rostochiensis\pathogenicity\plant parasitic nematodes\potatoes\distribution\surveys
GL: Bulgaria
AN: 0T06701858

TI: Detection of chitinases in potato plants following infection with the potato cyst nematodes, Globodera rostochiensis and G. pallida.
AU: Rahimi, S.\ Perry, R. N.\ Wright, D. J.
JN: Nematologica
YR: 1998
VL: 44
NO: 2
PP: 181-193
LA: En
MS: 41 ref.
AA: Entomology & Nematology Department, IACR-Rothamsted, Harpenden, Herts., AL5 2JQ, UK.
AB: Changes in chitinase activity were observed following infection of 3 potato clones (12380, P55/7 and Maris Piper) with 4 pathotypes of Globodera rostochiensis and G. pallida. Following invasion, the intercellular fluid of the leaves of all the plants tested showed marked increases in exochitinase activity. In contrast, after removal of intercellular fluid the leaf homogenates showed only a limited increase in endochitinase activity. In roots, endochitinases were significantly increased in 12380 following invasion by G. pallida Pal and G. rostochiensis Ro1 and Ro5 but not by G. pallida Pa2/3. The largest increase in exochitinase activity in the roots of 12380 was observed after invasion by G. pallida Pa1. The possible role of these chitinases in potato-nematode interactions is discussed.
DE: plant parasitic nematodes\chitin\pest resistance\detection\potatoes\Globodera rostochiensis\Globodera pallida\damage\Solanum tuberosum
AN: 0T06701367\7K02301101\0P06813174

TI: Virulence spectra of aggressive Globodera pallida population.
AU: Amalraj, S. F. A.\ Rao, G. R.
JN: Indian Journal of Nematology
YR: 1997
VL: 27
NO: 1
PP: 41-45
LA: En
MS: 8 ref.
AA: Botany Department, Bharathidasan University, Tiruchirappalli, Tamil Nadu - 620 024, India.
AB: The virulence of 12 isolates of G. pallida from 12 villages in Tamil Nadu, India, was studied by rearing them on 2 highly resistant potato differentials. It took 6 generations to develop a notable degree of virulence.
DE: Globodera pallida\virulence\plant parasitic nematodes\potatoes\Solanum tuberosum
AN: 0T06701357\7K02301098

TI: Discrimination of European and Australian Globodera rostochiensis and G. pallida pathotypes by high performance capillary electrophoresis.
AU: Hinch, J. M.\ Alberdi, F.\ Smith, S. C.\ Woodward, J. R.\ Evans, K.
JN: Fundamental and Applied Nematology
YR: 1998
VL: 21
NO: 2
PP: 123-128
LA: En
LS: fr
MS: 14 ref.
AA: Plant Sciences & Biotechnology, Agriculture Victoria, La Trobe University, Bundoora, VC 3083, Australia.
AB: The use of high performance capillary electrophoresis (CE) as a tool to differentiate between representative populations of pathotypes of G. rostochiensis and G. pallida is described. Reproducible polypeptide profiles obtained by sodium dodecyl sulfate (SDS)-capillary gel electrophoresis displayed some peptides characteristic of G. rostochiensis and others characteristic of G. pallida. Polypeptide profiles of each of the pathotypes of G. rostochiensis Ro1, Ro2, Ro3, Ro4, Ro5, and G. pallida Pa1, Pa2/Pa3 were obtained. Profiles of Australian isolates from Victoria were of the Ro1 type and this pathotype classification was also determined by standard differential cultivar tests. The CE technique outlined is a reliable, reproducible technique which could aid with the differentiation of these pathotypes with minimum sample preparation.
DE: isoelectric focusing\identification\pathotypes\Globodera rostochiensis\Globodera pallida\plant parasitic nematodes\techniques
AN: 0T06701187

TI: Relationship between potato cyst nematodes and their principal host. I. A literature review.
AU: Mulder, A.\ Wal, A. F. van der
JN: Potato Research
YR: 1997
VL: 40
NO: 3
PP: 317-326
LA: En
MS: 59 ref.
AA: H. L. Hilbrands Laboratory for Soil-borne Pests and Diseases, P. O. Box 323, 9400 AH Assen, Netherlands.
AB: A description of the biology of Globodera rostochiensis and G. pallida, and symptom development in potato crops is presented. This is followed by an overview of resistance and tolerance research and an explanation of how resistance derived from Solanum andigena was deployed in integrated control schemes on sandy and sandy peat soils in the north-east of the Netherlands. The frequent use of this resistance source resulted in the predominance of 'new' pathotypes of G. rostochiensis and of G. pallida. The ability of the cyst nematodes to respond to new types of resistance with new pathotypes makes the search and breeding for resistance a continuing process. The absence of tolerance in ex S. vernei (VT(n))(2) 62-33-3 cultivars showed that resistance, if it is to be of use in severely infested fields, must be combined with an appreciable level of tolerance.
DE: Globodera rostochiensis\Globodera pallida\biology\pathotypes\damage\pest resistance\tolerance\plant parasitic nematodes\reviews\potatoes\Solanum tuberosum subsp.
andigena\Netherlands\integrated control
AN: 0T06700843\7K02300613

TI: Field-trials on the influence of rotation, cultivar-resistance and chemical control on the abundance of potato cyst nematodes (Globodera pallida) grown on farm-fields and the yield.
FT: Einfluss von Fruchtfolge und Sortenresistenz sowie chemischer Bekampfung auf die Befallsentwicklung von Kartoffelnematoden (G. pallida) auf Praxisflachen und den Ertrag.
AU: Lauenstein, G.\ Osmers, K.
JN: Gesunde Pflanzen
YR: 1997
VL: 49
NO: 8
PP: 254-259
LA: De
LS: en
MS: 11 ref.
AA: Institut fur Pflanzenbau und Pflanzenschutz der Landwirtschaftskammer Weser-Ems (IPP), Sedanstr. 4, D-26121 Oldenburg, Germany.
AB: In field trials from 1988 to 1996, the influence of different rotations, cultivars and the application of a granulated nematicide were tested on fields infested by initially very low numbers of G. pallida, virulence group Pa2/3. The climatic conditions exerted the most important influence on the performance of the tested means. A mounting percentage of susceptible varieties of potatoes in the rotations enabled the nematode to reach the highest densities found. This detrimental effect could be neutralized by growing a highly resistant (and preferably tolerant) variety making use of rotations containing 33% rsp. 50% potatoes. The application of the nematicide resulted in a lower final density of nematode and yield increases as well in tuber-mass as starch. The results showed that even a potato-heavy rotation without applications of nematicide can be practiced successfully, if the available means (i.e. regular density assessment, choice of variety concerning resistance and tolerance and use of supporting agricultural measures) are applied in the necessary specific and integrated way.
DE: Globodera pallida\plant parasitic nematodes\chemical control\rotations\control\cultural
control\potatoes\nematicides\pest resistance\Solanum tuberosum
AN: 0T06700841\7K02300611

TI: Breeding for resistance to some pathotypes of cyst-forming nematode Globodera pallida in chosen potato genotypes.
FT: Slechteni na rezistenci vuci nekterym patotypum cystotvorneho had'atka Globodera pallida u vybranych genotypu brambor.
AU: Petr, P.\ Kuhn, R.
JN: Vedecke Prace - Vyzkumny a Slechtitelsky Ustav Bramborarsky v
Havlickove Brode
YR: 1996
NO: No. 12
PP: 59-69
LA: Cs
LS: en
MS: 8 ref.
AA: Potato Research Institute, Dobrovskeho 2366, 580-03 Havlicduv Brod, Czech Republic.
AB: During 1993-96, 241 potato genotypes were screened against various pathotypes of Globodera pallida. Of these, 13 were recommended for further testing particularly genotype 94.374/1 (Fianna ×  Dorett) which exhibit resistance to the highly virulent population Delmsen of pathotype Pa3.
DE: potatoes\Solanum tuberosum\Globodera pallida\plant parasitic nematodes\pest resistance\screening
AN: 7K02300186\0T06700847

TI: Genetic diversity of the potato cyst nematode in the Netherlands.
AU: Folkertsma, R. T.
YR: 1997
PP: 88 pp.
BN: ISBN 90-5485-748-X
LA: En
LS: nl
MS: 166 ref.
AB: The aim of this thesis was to study the intra- and interspecific variation of G. rostochiensis and G. pallida in the Netherlands and to develop a framework for the identification of potato cyst nematode populations to optimize the control by means of host plant resistance. The second chapter describes the application of RAPD for the amplification of species specific sequences from pools of individuals and single juveniles. The genetic variation between and within the 2 nematode species, as revealed by RAPDs and AFLPs, is studied in chapters 3 and 4, respectively. In chapter 5 the variation among G. pallida populations as revealed by RAPDs and 2-dimensional gel electrophoresis of proteins (2-DGE) is compared. Chapter 6 describes the influence of random genetic drift on the secondary founders of G. pallida in The Netherlands. In chapter 7 the quantitative variation in protein polymorphism, as revealed by 2-DGE, and virulence towards 2 resistant potato cultivars are
compared by studying 102 G. pallida populations from The Netherlands.
DE: Globodera rostochiensis\Globodera pallida\plant parasitic nematodes\genetic variation\identification\genetic diversity\virulence\techniques\rapd\potatoes\Netherlands\genetics\control\pest resistance
AN: 0T06700106\7K02300606

TI: Intra- and interspecific variability in Globodera, parasites of solanaceous plants, revealed by Random Amplified Polymorphic DNA (RAPD) and correlation with biological features.
AU: Thiery, M.\ Fouville, D.\ Mugniery, D.
JN: Fundamental and Applied Nematology
YR: 1997
VL: 20
NO: 5
PP: 495-504
LA: En
LS: fr
MS: 43 ref.
AA: Laboratoire de la Chaire de Zoologie de l'ENSA de Rennes, INRA, B.P. 29, 35653 Le Rheu Cedex, France.
AB: Inter- and intraspecific variability among species of Globodera, parasites of Solanaceae, were studied by host range and RAPD. Host range was studied among Nicotiana species and cultivars within G. tabacum sensu lato. RAPD was applied to 26 populations belonging to 6 putative Globodera species. Host range revealed clear differences allowing grouping in accordance with pathogenicity or virulence. 222 RAPD markers were obtained using 8, ten bases Operon primers (OPG-1, OPG-2, OPG-3, OPG-4-OPG-5, OPL-3, OPL-4, OPL-6). Different clustering programmes and a principal coordinate analysis were performed with RAPD data showing very few differences in the results. These dendrograms clearly revealed the existence of 4 OTU or species as G. rostochiensis, G. pallida, G. tabacum and G. "mexicana". The clustering of these species was identical with that obtained previously with ribosomal DNA cistron ITS (Internal Transcribed Spacers) restriction analysis. Furthermore, the intraspecific clusterings were in very good accordance with host range grouping and with the hybridization results published previously.
DE: plant parasitic nematodes\identification\phylogeny\virulence\random amplified polymorphic dna\globodera\parasites\plants\correlation\molecular genetics\genetic markers\Solanaceae\host range\Globodera tabacum\Nicotiana
AN: 0T06700112

TI: Comparison of molecular patterns and virulence behaviour of potato
cyst nematodes.
AU: Fullaondo, A.\ Salazar, A.\ Barrena, E.\ Ritter, E.
JN: Fundamental and Applied Nematology
YR: 1997
VL: 20
NO: 5
PP: 425-433
LA: En
LS: fr
MS: 37 ref.
AA: Centro de Investigacion y Mejora Agraria-Granja Modelo, Apartado 46, 01080 Viloria-Gasteiz, Spain.
AB: Seven populations belonging to Globodera rostochiensis and G. pallida were analysed by means of RAPD markers, microsatellite primed PCR and 2-D gel electrophoresis of total proteins. A high degree of polymorphism was detected in all types of markers. Furthermore, virulence reactions of the nematode populations on a set of differential potato genotypes were recorded. Significant population and host effects as well as a highly significant interaction between these two variables were observed. Genetic distances between nematode populations based on molecular data and virulence reactions were computed. Cluster analyses were performed and the resulting distance matrices compared. A good consistency between the different dendrograms and highly significant correlation coefficients were observed when comparing the distance matrices derived from molecular data and virulence reactions. Practical applications of such molecular analyses to the study of nematode populations could provide indirect virulence testing and therefore recommendations of the appropriate potato cultivars for cultivation in infested soils.
DE: plant parasitic nematodes\techniques\genetic distance\globodera\nematoda\virulence\nematoda\patterns\virulence\behaviour\nematoda\Globodera rostochiensis\Globodera pallida\molecular genetics\genetic markers\potatoes\Solanum tuberosum
AN: 0T06700328\7K02300173

TI: Durability of resistance to Globodera pallida I. Changes in pathogenicity, virulence, and aggressiveness during reproduction on partially resistant potato cultivars.
AU: Schouten, H. J.\ Beniers, J. E.
JN: Phytopathology
YR: 1997
VL: 87
NO: 8
PP: 862-867
LA: En
MS: 26 ref.
AA: Centre for Plant Breeding and Reproduction Research (CPRO-DLO), PO Box 16, 6700 AA Wageningen, Netherlands.
AB: Changes in pathogenicity, virulence and aggressiveness of G. pallida populations over time were investigated. As a measure for pathogenicity, the reproduction factor on a partially resistant host was used. For aggressiveness, the reproduction factor on a susceptible reference host was used and for virulence, the ratio pathogenicity/aggressiveness was used. The G. pallida populations were reared in a glasshouse for 4 generations on potato cultivars with different levels of resistance. The cultivar Elkana did not increase pathogenicity significantly, but the more resistant cultivars Karakter and Darwina did. This increase in pathogenicity was caused by an increase in virulence, whereas aggressiveness generally was not significantly altered. The increase in virulence appeared to be caused by an enhanced ability of eggs to develop into cysts, and not by an increase in egg production/new cyst. The observed changes in virulence were predicted well by a simple numerical model. The rate of selection depended strongly on the nematode population. Rearing a mix of 2 different populations on a susceptible host strongly decreased the virulence, as predicted by
the Hardy-Weinberg equilibrium, although it increased the aggressiveness because of heterosis.
DE: plant parasitic nematodes\pest resistance\pathogenicity\virulence\reproduction\cultivars\solanum tuberosum\mathematical models\Globodera pallida\potatoes
GL: Netherlands
AN: 0T06700343\7K02300172

TI: Comparison of British populations of potato cyst nematodes with populations from continental Europe and South America using RAPDs.
AU: Blok, V. C.\ Phillips, M. S.\ Harrower, B. E.
JN: Genome
YR: 1997
VL: 40
NO: 3
PP: 286-293
LA: En
LS: fr
MS: 31 ref.
AA: Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK.
AB: Genetic variation between populations of Globodera pallida, primarily from Britain but including populations from continental Europe and South America and 2 G. rostochiensis populations, was examined using RAPD. Fourteen primers were used and 250 amplification products observed. A comparison was made of the similarities between the species and, within G. pallida, between populations from Britain, The Netherlands, Germany, and Switzerland, of the pathotypes Pa2 and Pa3. In addition, one Pa1 population and two others from South America were included. On the basis of the RAPD analysis, all the Pa2-Pa3 populations, except one from Scotland (Luffness), constituted a single group with no clear distinction based on pathotype designation. The Luffness population is known to be distinct in its virulence. The data indicated that the main Pa2-Pa3 group could be subdivided based on geographic origin, but this is not well supported by bootstrap analysis. The Pa1 population and the 2 populations from South America all formed distinct groups.
DE: plant parasitic nematodes\nematoda\genetic variation\globodera pallida\introduction\south america\nematoda\populations\europe\Globodera rostochiensis\genetics\solanum tuberosum
AN: 7K02201074\0T06601671

TI: Modelling the effect of random genetic drift on the virulence of potato cyst nematodes.
AU: Schouten, H. J.
JN: Nematologica
YR: 1997
VL: 43
NO: 2
PP: 173-184
LA: En
LS: fr
MS: 6 ref.
AA: Centre for Plant Breeding and Reproduction Research (CPRO-DL0), P.O. Box 16, 6700 AA Wageningen, Netherlands.
AB: The standard deviation å, caused by random genetic drift, is inversely proportional to the square root of the number of Globodera cysts sampled, decreases at increasing mating frequency per female, and attains its highest values at intermediate levels of cultivar susceptibility to the original population. Relative susceptibility of a cultivar is the reproduction factor P(j)/P(i) on this cultivar relative to that on a susceptible reference cultivar, at a low inoculum density. If only
one cyst is taken, then
å equals 20-30% at a relative susceptibility to the original population of 20-80%, under assumptions given in the text. If more than 10 cysts are drawn, then å is lower than 9%. Increasing the mating frequency from one to 25 decreases the random genetic drift by approximately the same extent as doubling the number of cysts per sample. Virulence based on two independent genes hardly changes drift compared to monogenic virulence. If the number of eggs per cyst is lower than 15, then additional random genetic drift arises. The results of this study may be used to judge how many cysts are needed in a sample to keep the sampling error sufficiently small, and for investigations on founder effects.
DE: plant parasitic nematodes\nematoda\founder effect\globodera pallida\resistance\statistics\genetic drift\virulence\nematoda\Globodera rostochiensis\techniques\sampling\genetics\genetic drift\Globodera
AN: 0T06601195\7K02201069

TI: RFLP analysis in Canary Islands and north European populations of potato cyst nematodes (Globodera spp.): hybridization with cloned fragments.
AU: Gonzalez, J. A.\ Phillips, M. S.\ Trudgill, D. L.
JN: Nematologica
YR: 1997
VL: 43
NO: 2
PP: 157-172
LA: En
LS: de
MS: 23 ref.
AA: Departamento de Agroecologia, Centro de Ciencias Medioambientales, CCMA-CSIC, Serrano 115 dpdo, E-28006 Madrid, Spain.
AB: Four random probes from a Globodera pallida DNA library and one rDNA repeat probe from flax were used to highlight specific fragments in total DNA restricted with the endonucleases Bam HI, Eco RI, Eco RV, and Hind III, from 26 potato cyst nematode (PCN) populations (G. rostochiensis and G. pallida). The percentage similarity between species was low (%sm = 45.6). Cluster and principal coordinate analysis allowed the hypothesis about the epidemiology of these populations. In the G. rostochiensis group, the populations representing pathotypes Ro2, Ro3, Ro4 and Ro5 may have been derived from the same introduction. Canarian populations R1, R2, R6, R7, and R10 were distinct from all the controls but R4 and R5 were close to the British Ro1 population. In the G. pallida group, the Luffness population was distinct from all others suggesting that it may represent a distinct introduction of PCN into the British Isles. Canarian population P9 had ten markers which were absent from the European control populations and it is possible that this population represents a distinct introduction of G. pallida into the Island of Tenerife.
DE: plant parasitic nematodes\DNA probes\evolution\epidemiology\restriction fragment length polymorphism\nematoda\pathotypes\canary islands\restriction fragment length polymorphism\analysis\european\populations\nematoda\globodera\hybridization\Globodera pallida\Globodera rostochiensis\techniques\identification
GL: Canary Islands
AN: 0T06601010\7K02201068

TI: Evolution of resistance and virulence in relation to the management of nematodes with different biology, origins and reproductive strategies.
AU: Blok, V. C.\ Ehwaeti, M.\ Fargette, M.\ Kumar, A.\ Phillips, M. S.\ Robertson, W. M.\ Trudgill, D. L.
JN: Nematologica
YR: 1997
VL: 43
NO: 1
PP: 1-13
LA: En
MS: 21 ref.
AA: Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK.
AB: The host range, the resistant and susceptible responses, reproductive strategies and gene flow, host specialisation and durability of control using resistant cultivars, in plant parasitic nematodes are reviewed and discussed. Globodera spp. as an example of a host-specific association is contrasted with certain Xiphinema and the mitotically parthenogenetic species of Meloidogyne.
DE: evolution\pest resistance\nematoda\gene flow\genetics\globodera\meloidogyne\resistance mechanisms\xiphinema\evolution\resistance\virulence\management\biology\plant parasitic nematodes\reviews
AN: 0T06600996

TI: Determination of species and pathotypes of potato cyst nematodes in Nilgiri hills.
AU: Prasad, K. S. K.
JN: Journal of the Indian Potato Association
YR: 1996
VL: 23
NO: 1/2
PP: 40-45
LA: En
MS: 14 ref.
AA: Central Potato Research Station, Muthorai, Nilgiris 643 004, Tamil Nadu, India.
AB: The populations of potato cyst nematodes from 6 major potato growing localities of the Nilgiri hills, Tamil Nadu, India, representing varying ecological conditions, were characterised to species and
pathotypes by using standard differential host tests. Based on the colour of developing females on susceptible potato cv. Kufri Jyoti, mixed populations of Globodera pallida and G. rostochiensis from 5 localities and a pure population of the later species from 1 locality were observed. The development of females on other differential hosts suggested the presence of 3 pathotypes each i.e. Ro(1) , Ro(2) and Ro(3) in G. rostochiensis and Pa(1), Pa(2) and Pa(3) in G. pallida.
DE: nematoda\determination\species\pathotypes\plant parasitic nematodes\solanum tuberosum\Globodera pallida\Globodera rostochiensis\identification\potatoes\India\Globodera\surveys\Tamil Nadu
GL: India\Tamil Nadu
AN: 7K02200588\0T06601251

TI: Genetic variation and pathotype response in potato cyst-nematodes from Cyprus.
AU: Zaheer, K.\ Fleming, C.\ Turner, S. J.\ Philis, J.
JN: Nematologia Mediterranea
YR: 1996
VL: 24
NO: 2
PP: 161-167
LA: En
MS: 14 ref.
AA: Department of Agricultural Zoology, Queen's University of Belfast, New Forge Lane, Belfast, UK.
AB: Thirty-six samples of potato cyst nematodes (PCN) from Cyprus (Xylophagou and Troodos regions) were examined for pathotype composition and genetic variation using differential potato clones and isozyme analysis. Isoelectric focusing (IEF) analysis revealed Globodera rostochiensis to be predominant in the samples, with 32 out of 36 populations consisting of this species. Of the remaining 4 samples, 3 were G. rostochiensis/G. pallida mixtures and one was pure G. pallida. These analyses were confirmed in the pathotyping tests and subsequent electrophoretic analysis of cysts produced in these tests.
DE: plant parasitic nematodes\solanum tuberosum\genetic variation\cyprus\races\Globodera rostochiensis\Globodera pallida\potatoes
GL: Cyprus
AN: 0T06600761\7K02200578

TI: Identification of pathogenesis-related proteins induced in leaves of potato plants infected with potato cyst nematodes, Globodera species.
AU: Rahimi, S.\ Perry, R. N.\ Wright, D. J.
JN: Physiological and Molecular Plant Pathology
YR: 1996
VL: 49
NO: 1
PP: 49-59
LA: En
MS: 33 ref.
AA: Entomology & Nematology Department, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK.
AB: The activity of b-1,3-glucanases and
b-D-glucosidases increased in the leaves of potato plants infected by species of Globodera. The reactions of cultivars to nematode infection differed, indicating that different pathotypes of the same species or different species of potato cyst nematode elicited the appearance of different classes of b-1,3-glucanases. The analysis of infected roots showed no significant increase in b-1,3-glucanase activity. The importance of b-1, 3-glucanases in the resistance response and other possible defence-related functions is discussed.
DE: plant parasitic nematodes\root crops\fibre plants\host parasite relationships\potatoes\Globodera\solanum tuberosum\gene expression\
b-glucosidase\b-glucanase
AN: 0P06701580\0T06600318\7K02200164

TI: Observations on the specificity of Globodera pallida and G. rostochiensis diagnostic proteins to amphids of Globodera species.
AU: Curtis, R. H. C.\ Segers, I.\ Evans, K.
JN: Nematologica
YR: 1996
VL: 42
NO: 4
PP: 466-480
LA: En
LS: de
MS: 31 ref.
AA: Entomology and Nematology Department, IACR-Rothamsted, Harpenden, Herts, AL5 2JQ, UK.
AB: Globodera pallida and G. rostochiensis proteins (Gp-5.7 and Gr-5.9, of pl 5.7 and 5.9 resp.) were purified from acrylamide gel bands excised after isoelectric focusing. A panel of monoclonal antibodies (MAbs) and a monospecific polyclonal antibody (PC 320) were produced to Gp-5.7 and Gr-5.9, resp. The polyclonal antibody reacted equally, but some of the MAbs reacted differentially with the two species of potato cyst nematodes (PCN). MAb IACR Gp-5.7.1 recognises a proteic epitope and preliminary results indicated that the molecule is N-terminally blocked. This MAb bound only to antigens derived from cysts containing live eggs. Proteins related to Gp-5.7 and Gr-5.9 were identified in all pathotypes of potato cyst nematodes and in other Globodera species, but not in the Heterodera species tested. The antigen has the same molecular weight in all the species tested, but the isoelectric points varied between the different species. The pl values were 5.9 for G. rostochiensis, 5.7 for G. pallida and 5.77 for G. tabacum tabacum, G. t. solanacearum, G. t. virginiae and G. "mexicana". This might indicate that the Globodera species from Mexico and the USA are more closely related to each other, than they are to G. pallida or G. rostochiensis. Immunofluorescence studies demonstrated that the MAb bound to the amphids of the Globodera species tested; the genus-specificity of this molecule might account for very specialized functions in the amphids of these nematodes. The differences in isoelectric points and antigenicity observed probably indicate that the Globodera species have different isoforms of the same molecule which might be related to specific functions in the nematode amphids.
DE: plant parasitic nematodes\identification\globodera pallida\proteins\globodera\species\Globodera rostochiensis\biochemistry
AN: 0T06600095\7K02200160

TI: Estimation of genomic variation between British populations of the potato cyst nematode Globodera pallida using RAPD-PCR.
AU: Burrows, P. R.\ Halford, P. D.\ Evans, K.
JN: Molecular Ecology
YR: 1996
VL: 5
NO: 5
PP: 697-701
LA: En
MS: 19 ref.
AA: Entomology and Nematology Department, 1ACR-Rothamsted, Harpenden, Herts AL5 2JQ, UK.
AB: Random amplified polymorphic DNA (RAPD) has been used to investigate the interrelationships of 20 populations of Globodera pallida collected originally from field soils around the UK. RAPD analysis revealed a high level of relative genomic diversity within British G. pallida but there was no general correlation of genomic similarity with geographic distribution. Two populations of pathotype Pa1 were clearly divergent from the bulk of G. pallida and might represent a distinct introduction. Two other populations, from Scotland and Wales, were also dissimilar from each other and from the rest of the G. pallida populations.
DE: plant parasitic nematodes\globodera pallida\virulence\globodera pallida\estimation\variation\populations\genetic variation
GL: UK
AN: 0T06600176\7K02200157

TI: Virulence of Canarian populations of potato cyst nematodes (Globodera spp.).
AU: Gonzalez, J. A.\ Phillips, M. S.\ Trudgill, D. L.
JN: Nematologica
YR: 1996
VL: 42
NO: 2
PP: 198-210
LA: En
LS: de
MS: 17 ref.
AA: Centro de Ciencias Medioambientales, C.S.I.C., Serrano 115 bis, Madrid 28006, Spain.
AB: The virulence spectrum of Globodera pallida and G. rostochiensis, from the Island of Tenerife was assessed and compared with that found in Europe. Within the G. rostochiensis populations, all the Canarian populations, with the exception of one (R2), were avirulent to the H1 resistance gene and therefore belong to the virulence group Rol/RZo4. Within the G. pallida populations from Tenerife it was apparent that the virulence gene which overcomes the H2 resistance gene is present only at a low frequency. Four populations, P4, P7, P8 and P13, would be classified as pathotype Pa1. A wide range of variation in virulence against clones derived from S. vernei was observed, indicating a continuum of virulence, rather than discrete pathotypes. There was some correlation between the fitness of the populations on the hosts derived from S. vernei and those with no resistance, but less correlation between virulence on the ex-S. vernei clones and one derived from ex-S. tuberosum ssp. andigena CPC 28082. The reproduction of the G. pallida populations on three ex-S. vernei clones also indicated the increasing resistance is predominantly additive and that the nature of virulence towards the three ex-S. vernei clones tested is similar. The differences in the multiplication of the populations on a particular clone may reflect the number of resistance genes present in the clone. A clone derived from ex-S. tuberosum ssp. andigena CPC 2802 was comparatively uniformly resistant to all the populations. Its resistance appears to be different from that in the ex-S. vernei clones and to interact with at least in part, different genes in G. pallida for virulence. The nature of resistance in the different clones tested and aspects concerning the epidemiology of potato cyst nematodes are discussed.
DE: plant parasitic nematodes\nematoda\globodera pallida\virulence\pathotypes\populations\globodera\Globodera rostochiensis\Canary Islands
GL: Canary Islands
AN: 7K02101000\0T06501032

TI: A model examining the effect of environmental sex determination in parasites on the breakdown of monogenic host resistance.
AU: Schouten, H. J.
JN: Nematologica
YR: 1996
VL: 42
NO: 1
PP: 80-88
LA: En
LS: fr
MS: 9 ref.
AA: Centre for Plant Breeding and Reproduction Research (CPRO-DLO), P.O. Box 16, 6700 AA Wageningen, Netherlands.
AB: If sex determination of a parasite depends on feeding conditions on its host, then good feeding conditions may favour development into one sex, but poor feeding conditions may enhance development into the other sex. This implies that a resistant host may exert a selection pressure towards virulence via one sex, but a selection pressure towards avirulence via the other sex. Continuous cultivation of a resistant host may therefore lead to an equilibrium frequency of avirulent parasites, and consequently to a durable partial resistance to the population. In this way the parasite may maintain its genetic diversity, at the expense of its reproduction rate. In a previous paper (Schouten, 1994) this phenomenon has been elaborated mathematically for complete, monogenic resistance. In the present paper the derivation is widened towards partial monogenic resistance to avirulent parasites, and is worked out further for potato cyst nematodes (Globodera rostochiensis and G. pallida). The equilibrium frequency of avirulent nematodes ranges from 0 to 100 5, but the ensuing durable resistance is lower than 50%. Thin roots and high nematode densities lower the equilibrium frequency of avirulent nematodes and the matching resistance level.
DE: plant parasitic nematodes\globodera rostochiensis\globodera pallida\virulence\population genetics\sex determination\parasites\breakdown
AN: 0T06500565\7K02100594

TI: Genetic mapping of a wide spectrum nematode resistance gene (Hero) against Globodera rostochiensis in tomato.
AU: Ganal, M. W.\ Simon, R.\ Brommonschenkel, S.\ Arndt, M.\ Phillips, M. S.\ Tanksley, S. D.\ Kumar, A.
JN: Molecular Plant-Microbe Interactions
YR: 1995
VL: 8
NO: 6
PP: 886-891
LA: En
MS: 33 ref.
AA: Institute for Plant Genetics and Crop Plant Research, Corrensstr. 3, D-06466 Gatersleben, Germany.
AB: The Hero gene confers resistance to a wide spectrum of pathotypes of Globodera rostochiensis. This gene has been introgressed form the wild tomato tomato. RFLP and RAPD analysis has been used for the targeted search of the L. pimpinellifolium segment. The resistant line LA 1792 contains a single introgressed segment on chromosome 4, which is characterized by three RFLP markers from the high-density RFLP map of tomato. The map position of the Hero gene is not equivalent to any of the previously mapped G. rostochiensis resistance genes in potato. For the fine mapping of the Hero gene in large populations, four additional markers were identified in the introgressed region. After analysing more than 800 gametes for recombination, one marker was found only 0.4 cm away from the Hero gene. YAC clones isolated from a region near the Hero gene indicated that in this area of the genome, the kb/cM ratio is relatively low (<450 kb/cM) and chromosome walking should
be feasible in order to isolate this gene.
DE: plant parasitic nematodes\fruit vegetables\genetic mapping\globodera rostochiensis\resistance\control\pest resistance\tomatoes
AN: 0T06500756

TI: Gene pool similarities of potato cyst nematode populations assessed by AFLP analysis.
AU: Folkertsma, R. T.\ Voort, J. N. A. M. R. van der\ Groot, K. E. de\ Zandvoort, P. M. van\ Schots, A.\ Gommers, F. J.\ Helder, J.\ Bakker, J.
JN: Molecular Plant-Microbe Interactions
YR: 1996
VL: 9
NO: 1
PP: 47-54
LA: En
MS: 36 ref.
AA: Wageningen Agricultural University, Department of Nematology, P.O. Box 8123, 6700 ES Wageningen, Netherlands.
AB: AFLP was used to characterize 24 potato cyst nematode populations. This novel DNA fingerprinting technique enabled the identification of 987 marker loci by screening only 12 primer combinations. Data on presence or absence polymorphisms and data on the intensities of corresponding DNA fragments were collected. Separate analysis of both data sets revealed similar dendrograms for the nine G. rostochiensis populations included in this study. Both dendrograms consisted of two groups containing three and five related populations, respectively. One population differed from either of these groups. Each group represented a different pathotype as defined by Kort et al. Previously, a similar arrangement was found after analysis of the genetic variation using random amplified polymorphic DNA. For the 15 G. pallida populations analysed, complex AFLP patterns were obtained and therefore only qualitative AFLP data were used. Incongruities were observed between clustering on the basis of AFLP data and classical pathotyping. This strongly confirms earlier findings obtained with RAPDs, because the AFLP markers used in this study outnumbered the population characteristics revealed by RAPDs by a factor of five. To arrive at a reliable pathotype designation of potato cyst nematode populations molecular data and virulence characteristics should be integrated. Possible causes for the difference in distribution of polymorphisms among G. rostochiensis and G. pallida populations are discussed.
DE: plant parasitic nematodes\populations\analysis\Globodera rostochiensis\genetics
AN: 0T06500599\7K02100580

TI: Analysis of somatic hybrids between two sterile dihaploid Solanum tuberosum L. breeding lines. Restoration of fertility and complementation of G. pallida Pa2 and Pa3 resistance.
AU: Rasmussen, J. O.\ Nepper, J. P.\ Rasmussen, O. S.
JN: Theoretical and Applied Genetics
YR: 1996
VL: 92
NO: 3/4
PP: 403-410
LA: En
MS: 35 ref.
AA: Department of Molecular Biology, University of Aarhus, C.F. Möllers Alle 130, DK-8000 Aarhus, Denmark.
AB: Resistance to Globodera pallida pathotypes Pa2 and Pa3 was introduced into tetraploid S. tuberosum lines by sexual crossing with 2 diploid clones of the wild species S. vernei. Extraction of dihaploids from 2 selected tetraploid lines following pollination with S. phureja IVP101 was carried out and 2 dihaploid clones selected DHAK11 and DHAKFourteen somatic hybrids generated by electrofusion of mesophyll protoplasts from a non-flowering clone, DHAK11, and a male-sterile clone, DHAK33, were grown in the greenhouse and subjected to morphological assessments and tests for fertility and resistance to the white potato cyst nematode G. pallida pathotypes Pa2 and Pa3. The ploidy level of the hybrids ranged from 38 to 63 chromosomes. All hybrids developed flowers with violet petals except for one, hy-56, that possessed red petals. The colour of the tuber skin was purple in all hybrids except in hy-56 where the tuber skin was red. All of the hybrids were female fertile and generated viable seeds. Near-tetraploid hybrids produced the highest number of seeds per fruit and these seeds had a normal size. Hybrids with 58 or more chromosomes produced smaller seeds and less seeds per fruit. The germination frequency of the seeds was not influenced by the chromosome number of the hybrids. Pollen viability was determined and the male fertility of three hybrids was tested. Pollination with these three hybrids gave rise to fruit development, but only one produced viable seeds. The hybrids were tested for resistance to G. pallida pathotypes Pa2 and Pa3. A high level of resistance to Pa3, inherited from one parental clone, DHAK11, and a high level of resistance to Pa2, inherited from the other parental clone, DHAK33, was combined in four hybrids. These results demonstrate that protoplast fusion is an efficient method for restoring the fertility of somatic hybrids generated from sterile parent clones, and is a powerful procedure for the complementation of multigenetic disease resistance traits in potato breeding lines.
DE: globodera pallida\solanum vernei\fertility\solanum tuberosum\analysis\hybrids\breeding\lines\complementation\pest resistance\chromosome number\seed germination\fruits\plant parasitic nematodes\somatic hybridization\interspecific hybridization\potatoes\wild relatives\protoplast fusion\Solanum phureja\genetic resources\pests\resistance\germination\control
AN: 0P06607357\7B00804163\6C00501827\7K02100876\7G01903505\0T06600319