Showing papers on "Globodera rostochiensis published in 2007"

Morphological and Molecular Identification of Globodera pallida Associated with Potato in Idaho.

Abstract: The identity of a newly discovered population of pale potato cyst nematode Globodera pallida associated with potato in eastern Idaho was established by morphological and molecular methods. Morphometrics of cysts and second-stage juveniles were generally within the expected ranges for G. pallida with some variations noted. The Idaho population and paratype material from Epworth, Lincolnshire, England, both showed variations in tail shape, with bluntly rounded to finely pointed tail termini. Compared to literature values for the paratypes, second-stage juveniles of the Idaho population had a somewhat shorter mean body length, and cysts had a slightly higher mean distance from the anus to the nearest edge of the fenestra. PCR-RFLP of the rDNA ITS region, sequence-specific multiplex PCR and DNA sequence comparisons all confirmed the identity of the Idaho population as G. pallida. The ITS rDNA sequence of the Idaho isolate was identical to those from York, England, and the Netherlands. Species-specific primers that can positively identify the tobacco cyst nematode Globodera tabacum were also developed, providing a new assay for distinguishing this species from G. pallida and the golden potato cyst nematode Globodera rostochiensis.

Sequence and characterization of six mitochondrial subgenomes from Globodera rostochiensis: multipartite structure is conserved among close nematode relatives.

Abstract: 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.

Structural and functional characterization of a novel, host penetration-related pectate lyase from the potato cyst nematode Globodera rostochiensis

Abstract: SUMMARY The cell wall, a strong extraprotoplasmic layer surrounding plant cells that mainly consists of a variety of polysaccharides, constitutes a major barrier for potential parasites. Plant-parasitic nematodes are well equipped to overcome this barrier as they produce and secrete cell-wall-degrading enzymes. Expression profiling of various life stages of the potato cyst nematode Globodera rostochiensis revealed a novel pectate lyase gene (Gr-pel2, 759 bp). The Gr-PEL2 protein showed highest similarity to pectate lyases from the facultative plant-parasitic nematodes Bursaphelenchus mucronatus and B. xylophilus and the soil-inhabiting saprophytic Streptomyces and Frankia species (i.e. 40-42% identity and 58-60% similarity), whereas only a remote relatedness to the previously identified Gr-PEL1 was observed (i.e. 28% identity and 43% similarity). Transient expression of Gr-pel2 in leaves of Nicotiana benthamiana resulted in severe malformations of the infiltrated tissues, not relating to maceration and soft rot symptoms. Ca(2+) is known to be essential for pectate lyase activity, and the most likely calcium-binding site was identified in the Gr-PEL2 protein by combining homology modelling of the three-dimensional structure, site-directed mutagenesis and transient expression in leaves. A highly charged cleft in Gr-PEL2, which is likely to be involved in substrate binding and which is also significantly more hydrophobic in Gr-PEL1, was shown to be essential for protein activity. Our results underline the broad spectrum of pectate lyases and cell-wall-degrading enzymes necessary for successful parasitism by cyst nematodes.

Potato cyst nematodes: plant host status and their regulatory impact

Abstract: Sullivan, M. J., R. N. Inserra, J. Franco, I. Moreno-Leheude, and N. Greco. 2007. Potato cyst nematodes: Plant host status and their regulatory impact. Nematropica 37:193-201. The known host range of potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) includes mainly Solanum species and a few species of Datura, Hyoscyamus, Lycopersicon, Physalis, Physoclaina, Salpiglossis, and Saracha, all in the Solanaceae family. The unreported results of a host study conducted in Chile using a local population of Globodera rostochiensis pathotype Ro1 indicate that Datura ferox, Nicotiana acuminata, Solanum ligustrinum and S. pinnatum allowed nematode infection and reproduction. Oca (Oxalis tuberosa) was not infected by potato cyst nematodes in field and greenhouse studies conducted in Bolivia and Peru. These findings conflict with those of a previous report of Globodera populations infecting oca. An updated list of potential PCN hosts based on the literature and on the current study is included in this paper.

The effect of five composts of different origin on the survival and reproduction of Globodera rostochiensis

Abstract: Five composts of different origin (C1: fresh olive pomace, straw, chicken manure and urea; C2: fresh olive pomace, cow manure, lettuce residues, straw and sawdust; C3: sewage sludge and municipal green residues; C4: grass, leaves, tree branches and soil; C5: by-product from penicillin production (mycelium), straw and sawdust, were tested for the control of the cyst nematode, Globodera rostochiensis, on potato in pot experiments. Composts were mixed with the nematode-infested soil at the rates of 1.0, 2.5, 5.0 and 10.0% w/w. A significant reduction in the number of eggs and juveniles was observed at all concentrations of the tested composts; compost from olive pomace mixed with urea resulted in the greatest decrease.

Occurrence of Potato Cyst Nematode, Globodera rostochiensis, on Potato in the Saint-Amable Region, Quebec, Canada.

Abstract: Potato (Solanum tuberosum L. subsp. tuberosum) is one of the most important food crops in Canada. Potato cyst nematodes, Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959 and Globodera pallida (Stone, 1973) Behrens, 1975, are considered the most economically important nematode pests of potatoes worldwide and are the subject of strict quarantine regulations in many countries including Canada. In Canada, G. rostochiensis was found in the Saanich Peninsula of Vancouver Island, British Columbia and both G. rostochiensis and G. pallida are present on the island of Newfoundland (3). During August of 2006, soil and roots of potato plants collected from a 19.2-ha field in the Saint-Amable region, Quebec, were submitted to the Nematology Laboratory, Canadian Food Inspection Agency, Ottawa. Golden, spherical-shaped cysts were found associated with the roots and were also extracted from the soil. The nematodes recovered were identified by morphological and morphometric analysis and DNA analysis...

Management of potato cyst nematodes, Globodera spp. through biological control

Abstract: Three bio-control agents viz., Pseudomonas fluorescens, Paecilomyces lilacinus and Trichoderma viride were evaluated for the management of potato cyst nematodes (PCN), Globodera rostochiensis and G. pallida under field conditions. Application of P. lilacinus multiplied on neem cake (containing 7 × 108 colony forming units (cfu)/g) @ 10 kg/ha and P. fluorescens in talc (containing 15 × 108 cfu/g) @ 10 kg/ha reduced the penetration of roots by the juveniles of potato cyst nematodes at 45 days after planting by 68.2 and 63.4 per cent respectively. Significant reduction in cyst count and egg population was observed in treatments that received P. lilacinus or P. fluorescens @ 10 kg/ha. The results revealed that these two treatments were equally effective in reducing the population of PCN and increased yield of potato significantly. The potato tuber yield was higher by 88.2 and 76.2 per cent (over control) respectively in Paecilomyces and Pseudomonas treatments.

Studies on the effect of mycorrhization of potato roots on the hatching activity of potato root leachate towards the potato cyst nematodes, Globodera pallida and G. rostochiensis

Abstract: Successful mycorrhization of potato plants cv. Golden Wonder was achieved with three commercial preparations of arbuscular mycorrhizal fungi (AMF): Vaminoc (mixed-isolate inoculum) and two of its components, Glomus intraradices and Glomus mosseae. Potato cyst nematode hatching assays were conducted on the potato root leachate (PRL) produced by inoculated and non-inoculated potato plants to examine the effect of AMF inoculation on the hatching response of the two PCN species, Globodera rostochiensis and G. pallida. The overall hatch response of G. rostochiensis to the potato root leachate was greater than G. pallida. Root leachates from Vaminoc- and G. mosseae-inoculated plants were found to stimulate the hatch of G. pallida in the first 3 weeks after shoot emergence. Fractionation of root leachates with standardised carbon content by Sephadex G-10 chromatography revealed multiple AMF effects on hatching factor (HF) production. Root leachates from Vaminoc-inoculated plants contained markedly more G. pallida-active HF than all other treatments; by contrast, PRL from the three AMF treatments exhibited little variation in the quantity of G. rostochiensis-active HF produced. Several HF were PCN species-specific or species-selective, with those resolved from the G. intraradices and G. mosseae PRL profiles exhibiting an apparent preference for G. rostochiensis rather than G. pallida. Mycorrhization also significantly increased the root dry weight of plants.

Influence of components of Globodera rostochiensis cysts on the in vitro hatch of second-stage juveniles

Abstract: The effects of cyst components of the potato cyst nematode, Globodera rostochiensis, on in vitro hatching of juveniles were evaluated. Aqueous homogenates of eggs and cyst walls, and aqueous rinses of cyst walls and eggs were examined. Homogenates of cyst walls or rinsates of either cyst walls or eggs each significantly increased hatch of juveniles five-fold compared with sterile distilled water controls. Cyst or egg homogenates induced significant increases (7.7-9.0-fold) in hatch of juveniles compared with controls. These values represent approximately 24.8-29.0% of the 31-fold induction of hatch of juveniles by potato root diffusate, routinely used to stimulate hatch in G. rostochiensis. The hatch inducing factor(s) in cyst homogenates was thermostable and retained activity after repeated freezing and thawing. Filter fractionation of cyst homogenate localised activity between molecular mass 0.5 kDa and 5 kDa, with no hatch inducing activity present above 5 kDa. Apparent depression of hatch induction at high concentrations of non-fractionated cyst homogenates suggests the presence of hatch inhibitors.

The occurrence and distribution of potato cyst nematodes in Croatia

Abstract: Potato cyst nematodes (PCN) Globodera rostochiensis (Wollenweber, 1923) Behrens, 1975 and Globodera pallida (Stone, 1973) Behrens, 1975 are the most troublesome pests of potatoes worldwide. Since 1968 there have been no investigations of the presence of PCN in ware potato lands in Croatia although these pests were recognised as an A1 plant-health quarantine species. After the first discovery of G. rostochiensis in the locality of Belica (Medjimurska County) in 2001, intensive monitoring of the distribution of PCN in Croatia started. In 2001 G. rostochiensis was detected in 55% of soil samples taken in ware potato lands. In 2002 G. rostochiensis was detected in 4.1% of soil samples and in 0.08% of soil samples in mixed populations with G. pallida. The pathotype Ro1 was found in all tested populations and Ro1 and Pa 2/3 were detected in populations from localities Vidovec, Ivanovec and Sivice. In 2003 G. rostochiensis was detected in 1.03% of soil samples, and also in 12.8% of soil samples collected in 2004. In 2003 cysts of G. rostochiensis were detected in several seed potato fields. These results indicate the urgent need for the application of further control measures to determine the presence and distribution of PCN in ware and seed potato lands in Croatia, in order to prevent the spread of PCN to non-infested areas. Integrated management strategies, neglected until 2001, have now been implemented and will prevent the build-up of infestation and replace the previous practices of monoculture, the use of short rotations and growing susceptible cultivars.

Comparison of the life cycle of potato cyst nematode (Globodera rostochiensis) pathotype Ro1 on selected potato cultivars

Abstract: The life cycle of Globodera rostochiensis pathotype Ro1 was studied under experimental conditions on selected potato cultivars (Korela, Albina, Vivaldi, Veronika, Vera, Monalisa, Victoria, Maranca, Desiree) in Slovakia during two growing seasons. Two peaks of second stage juveniles (J2) were found in the soil; the first peak three and four weeks after planting in the first and second year, respectively. The last J2 were found on 23 September. The number of J2 found in the second peak was much higher. First J2 associated with roots were observed 18 days, on middle early and seritonous cultivars 34 days after planting, but fourth stage juveniles (J4) were observed 40 days after planting in both cultivar groups. First adult males were found in soil 43 and 46 days after planting, respectively, and the last males two weeks later. White females filled with eggs were observed on roots 61 days after planting. The cycle from hatching of J2 in the soil to the hatching of J2 from brown cysts required 68 days in the first year and 60 days in the second year.

Monitoring of globodera spp. in lithuania using diagnostic morphometric analysis and polymerase chain reaction

Abstract: A total of 11,406 soil samples from 2,742 ha were collected in 10 administrative regions of Lithuania during the year 2006. A total of 672 cysts were selected and species were morphologically identified as Globodera rostochiensis. Of these cysts, 117 from 5 administrative regions of Lithuania were identified using polymerase chain reaction (PCR) analysis. Two pairs of species-specific primers were used to distinguish G. rostochiensis from G. pallida. This is the first application of a PCR method for identification of Globodera species in Lithuania.

Pathotypes and heterogeneity of Italian populations of Globodera rostochiensis and G. pallida

Abstract: Investigations were undertaken on the pathotypes and heterogeneity of Italian populations of the potato cyst nematodes, Globodera rostochiensis and G. pallida. All nematode populations were collected from the field and reproduced on a susceptible potato cultivar. To identify pathotypes, the differential Solanum spp. clones were grown in pots containing 1000 cm3 of soil infested with 5 eggs/cm3 of either nematode species, in a glasshouse at 20 ± 2 °C. Seventy days after potato emergence, the nematode population density in each pot was determined and the pathotype identified according to nematode reproduction rate. There were sixteen populations of G. rostochiensis and ten of G. pallida. All populations of G. rostochiensis reproduced more or less exclusively on both Solanum tuberosum cv. Spunta (susceptible) and cv. Saturna (possessing the H1resistant gene), so were considered pathotype Ro2. Of the populations of G. pallida, six were pathotype Pa3 as they reproduced on all of the differential clones, three did not reproduce on the clone (Vtn)262.33.3 of S. vernei and were classified as Pa2, and one population could not be clearly classified. The heterogeneity of seven populations of G. rostochiensis was investigated by examining the reproduction of ten single cyst derived populations for each of the original populations on potato cvs Spunta and Saturna, and on clone KTT/60.21.19 of S. kurtzianum. All of the single cyst populations derived from five of the parent populations were identical to their parent populations as they reproduced only on the first two cultivars, while one from a population from Puglia and five from a population from Calabria also reproduced on clone KTT/60.21.19.

Resistance of new italian potato breeding clones to cyst and root-knot nematodes

Abstract: Screening tests were conducted in glass-houses in 2006 and 2007 to assess the reaction of 27 new Italian potato (Solanum tuberosum) breeding clones to the potato cyst nematode, Globodera rostochiensis pathotypes Ro1 and Ro2, and to rootknot nematodes, Meloidogyne incognita host race 1 and M. javanica. Seven potato cultivars, known to be resistant to cyst nematodes, were also screened for their response to root-knot nematodes. The tests were conducted in 1 dm3 clay pots containing steam sterilized sandy soil infested with 10-15 eggs/cm3 of either pathotype of G. rostochiensis or 10,000 eggs and second stage juveniles/ pot of either root-knot nematode species. The glass-houses were maintained at 20 ± 2 °C for G. rostochiensis and at 26 ± 2 °C for Meloidogyne spp. The clones CS 8617 and MN 3-1469 R2 were resistant to all three nematode species, and the clone AND 97-15, known to be resistant to all European pathotypes of G. rostochiensis and G. pallida, was also resistant to M. incognita and moderately resistant to M. javanica. Fourteen of eighteen clones tested in 2006 and seven of the nine clones tested in 2007 were resistant to both pathotypes of G. rostochiensis. Two clones were resistant to both root-knot nematode species in 2006 and one clone moderately resistant to M. incognita and one moderately resistant to M. javanica in 2007. Some of the clones resistant to G. rostochiensis also possess good agronomic traits and have potential for registration as new cultivars.

Effect of pokeweed (Phytolacca americana L.) extract on hatching of Globodera rostochiensis and Meloidogyne spp.

Abstract: The effect of pokeweed fruit extract on hatching of the potato cyst nematode, Globodera rostochiensis, and the British root-knot nematode, Meloidogyne artiellia, was studied in Italy under laboratory conditions at 20 ± 1 °C. Cysts of G. rostochiensis were exposed to a series of increasing pokeweed fruit extract aliquots of 0.01, 0.02, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8 and 1.0 ml, which were added to 3 ml of sodium metavanadate 0.6 mM. Egg masses of M. artiellia were exposed to the same series of increasing fruit extract aliquots that were instead added to 3 ml of water. Controls were the hatching agent sodium metavanadate 0.6 mM, pokeweed root leachate and an aliquot of 1 ml of pokeweed fruit extract added to 3 ml of water for G. rostochiensis, and distilled water only for M. artiellia. The control treatment sodium metavanadate induced 20.7% hatching of G. rostochiensis, whereas the other two controls, pokeweed root leachate and 1 ml fruit extract in 3 ml of water, did not induce any hatching. The hatching of G. rostochiensis was not enhanced by adding to sodium metavanadate aliquots of 0.01-0.05 ml of pokeweed fruit extract, but was significantly increased by adding larger aliquots of 0.1-0.8 ml and suppressed (7.2%) by 1 ml. The greatest hatch increase of G. rostochiensis (81.6%) was provided by adding an aliquot of 0.4 ml of pokeweed fruit extract to 3 ml of sodium metavanadate. Hatching of M. artiellia was of 80.5 % in the control distilled water alone and was not enhanced by adding 0.01-0.2 ml of pokeweed fruit extract. However, water enrichment with increasing aliquots of 0.4-1 ml fruit extract significantly suppressed (17.5-37.7%) M. artiella hatching compared to the control. Pokeweed was a very good host for M. incognita and M. javanica and a non-host for M. artiellia.

The Canon of Potato Science: 14. Cyst Nematodes

Abstract: Cyst forming nematodes, or cyst nematodes, are one of the most specialized and successful plant-parasitic nematode pests of agriculture. The nematodes have a very narrow host range, which is opposite to root-knot nematodes which are polyphagous. In the case of potato, only the potato cyst nematodes (PCN) Globodera rostochiensis and G. pallida are able to infest the plants. The nematodes originate from South America, were introduced into Europe along with the potato tubers around 1600, and belong to the family Heteroderidae, genus Globodera. The life cycle of cyst nematodes is well adapted to the host and cyst nematodes can survive in various environments. The cyst, the dead body wall of the female, contains the eggs. The eggs hatch in the presence of the host, hatching being triggered by exudates from the host roots. Root exudates from Solanaceae, such as potato, tomato and woody nightshade (bitter sweet), activate these juveniles and can − under suitable environmental conditions − cause up to 80% of the nematodes to hatch. The juveniles enter the roots near the root tip and induce, by injecting saliva, a feeding cell or syncytial “transfer cell”. The juveniles become sedate and feed from the syncytia, until their development is complete after four moulds. After the 4th mould the female is round and swollen and protrudes from the root. The males are slender, leave the roots, mate and fertilize the females. After mating the female forms eggs and when the female dies, the cuticle tans to form a protective cyst with 200−500 eggs within. The life cycle is now complete and the whole cycle may take up to three months. The cyst falls of the root, waiting for the next suitable host plant. Cysts have the size of small pinheads and the juveniles are 0.5 mm long, so it is not the size but the number of nematodes that cause the damage. Infested plants show retarded growth and heavily infested fields normally show badly growing patches, especially under dry conditions. Potato yield can be decreased by up to 50%. Potato Research (2007) 50:259–262 DOI 10.1007/s11540-008-9076-3

Resistenz der Tomatensorte ‘Sparta’ gegen Kartoffelzystennematoden

Abstract: Die Resistenzuntersuchungen gegen Kartoffelzystennematoden an Tomatensorten wurden in Anlehnung an die Prufung von Kartoffelzuchtstammen durchgefuhrt. Dabei zeigte sich, dass ‘Sparta’ gegenuber dem gesamten Virulenzspektrum von Globodera rostochiensis (Ro1, Ro2/3, Ro4 und Ro5) resistent ist. Bei Globodera pallida ergab sich fur ‘Sparta’ eine Resistenz gegen die Port-Glenone- und Kalle-Population. Anfalligkeit liegt fur die Delmsen-Population vor und Teilresistenz bei der Chavornay- Population. Im Gewachshaus wurde im Pflanzkubel die Auswirkung der Kultivierung von ‘Sparta’ und der anfalligen Tomatensorte ‘Harzfeuer’ auf Verseuchungen mit G. rostochiensis (Ro1) zweijahrig und mit G. pallida (Delmsen-Population) einjahrig untersucht. Die Ausgangsverseuchungen lagen bei 1500 bzw. 5000 Larven je 100 ml Boden. ‘Sparta’ bewirkte in diesen Verseuchungsstufen einen Populationsruckgang von 70 bzw. 80 %. Gegenuber G. pallida (Delmsen-Population) lagen fur ‘Sparta’ die Vermehrungsraten (pf/pi-Werte) bei 4,4 bzw. 3,1. Die anfallige ‘Harzfeuer’ erreichte bei G. rostochiensis (Ro1) eine Vermehrungsrate von 36,0 bzw. 10,7. Unter Freilandbedingungen wurden in zwei Jahren auf 1- m²-Parzellen, verseucht mit G. rostochiensis (Ro1), erste Ergebnisse zu den von beiden Tomatensorten ausgelosten Populationsveranderungen ermittelt. Bei Ausgangsverseuchungen von 300 bzw. 1500 Larven je 100 ml Boden erreichte ‘Sparta’ einen Populationsruckgang von 83 bzw. 75 %. Fur die anfallige ‘Harzfeuer’ lag in diesem Bereich mit 3,6 die hochste Vermehrungsrate vor. ‘Sparta’ bietet mit der Resistenz und Toleranz gegen G. rostochiensis sowie einzelne Populationen von G. pallida die Voraussetzungen fur einen ertragreichen Anbau auf den mit diesen Bodenschadlingen verseuchten Gartenflachen. Stichworter: Globodera rostochiensis, Globodera pallida, Tomate, Resistenz, Toleranz Resistance of the ‘Sparta’ tomato cultivar to potato-cyst nematodes The resistance tests to potato-cyst nematodes on tomato varieties were carried out in a manner similar to that employed in the testing of potato breeding lines. ‘Sparta’ proved to be resistant to the whole virulence spectrum of G. rostochiensis (Ro1, Ro2/3, Ro4 and Ro5). In the case of Globodera pallida , ‘Sparta’ was resistant to the Port Glenone population and Kalle population but susceptible to the Delmsen population and partly resistant to the Chavornay population. Tests were carried out in planting tubs under greenhouse conditions to determine what effect the cultivation of ‘Sparta’ and the susceptible ‘Harzfeuer’ had on infestations with G. rostochiensis (Ro1) over a two-year period, and with G. pallida (Delmsen population) over a one-year period. The initial infestations were 1500 and 5000 larvae per 100 cc of soil. At these levels of infestation ‘Sparta’ brought about a population reduction of 70 per cent and 80 per cent respectively. In relation to G. pallida (Delmsen population) the multiplication rates (pf/pi values) were around 4.4 and 3.1 respectively. In relation to G. rostochiensis (Ro1) the susceptible ‘Harzfeuer’ registered multiplication rates of 36.0 and 10.7 respectively. Over a period of two years both tomato cultivars were grown on 1 sqm open-land plots infested with G. rostochiensis (Ro1) and the resulting changes in population changes were recorded. With initial infestations of 300 and 1500 larvae per 100 cc of soil ‘Sparta’ brought about a population reduction of 83 per cent and 75 per cent respectively. The susceptible ‘Harzfeuer’ cultivar produced the highest multiplication rate in this range with 3.6. ‘Sparta’, with its resistance to and tolerance of G. rostochiensis and certain populations of G. pallida , fulfils the requirements for a profitable cultivation of garden plots infected with soil pests. Keywords: Globodera rostochiensis, Globodera pallida , tomato, resistance, tolerance