Showing papers on "Globodera rostochiensis published in 2004"

Molecular cloning of the potato Gro1-4 gene conferring resistance to pathotype Ro1 of the root cyst nematode Globodera rostochiensis, based on a candidate gene approach

Abstract: The endoparasitic root cyst nematode Globodera rostochiensis causes considerable damage in potato cultivation. In the past, major genes for nematode resistance have been introgressed from related potato species into cultivars. Elucidating the molecular basis of resistance will contribute to the understanding of nematode-plant interactions and assist in breeding nematode-resistant cultivars. The Gro1 resistance locus to G. rostochiensis on potato chromosome VII co-localized with a resistance-gene-like (RGL) DNA marker. This marker was used to isolate from genomic libraries 15 members of a closely related candidate gene family. Analysis of inheritance, linkage mapping, and sequencing reduced the number of candidate genes to three. Complementation analysis by stable potato transformation showed that the gene Gro1-4 conferred resistance to G. rostochiensis pathotype Ro1. Gro1-4 encodes a protein of 1136 amino acids that contains Toll-interleukin 1 receptor (TIR), nucleotide-binding (NB), leucine-rich repeat (LRR) homology domains and a C-terminal domain with unknown function. The deduced Gro1-4 protein differed by 29 amino acid changes from susceptible members of the Gro1 gene family. Sequence characterization of 13 members of the Gro1 gene family revealed putative regulatory elements and a variable microsatellite in the promoter region, insertion of a retrotransposon-like element in the first intron, and a stop codon in the NB coding region of some genes. Sequence analysis of RT-PCR products showed that Gro1-4 is expressed, among other members of the family including putative pseudogenes, in non-infected roots of nematode-resistant plants. RT-PCR also demonstrated that members of the Gro1 gene family are expressed in most potato tissues.

A high-resolution map of the H1 locus harbouring resistance to the potato cyst nematode Globodera rostochiensis.

Abstract: The resistance gene H1 confers resistance to the potato cyst nematode Globodera rostochiensis and is located at the distal end of the long arm of chromosome V of potato. For marker enrichment of the H1 locus, a bulked segregant analysis (BSA) was carried out using 704 AFLP primer combinations. A second source of markers tightly linked to H1 is the ultra-high-density (UHD) genetic map of the potato cross SH × RH. This map has been produced with 387 AFLP primer combinations and consists of 10,365 AFLP markers in 1,118 bins ( http://www.dpw.wageningen-ur.nl/uhd/ ). Comparing these two methods revealed that BSA resulted in one marker/cM and the UHD map in four markers/cM in the H1 interval. Subsequently, a high-resolution genetic map of the H1 locus has been developed using a segregating F1 SH × RH population consisting of 1,209 genotypes. Two PCR-based markers were designed at either side of the H1 gene to screen the 1,209 genotypes for recombination events. In the high-resolution genetic map, two of the four co-segregating AFLP markers could be separated from the H1 gene. Marker EM1 is located at a distance of 0.2 cM, and marker EM14 is located at a distance of 0.8 cM. The other two co-segregating markers CM1 (in coupling) and EM15 (in repulsion) could not be separated from the H1 gene.

Control of potato cyst nematodes and economic benefits of application of 1,3-dichloropropene and granular nematicides

Abstract: Summary The two species of the potato cyst nematodes (PCN) Globodera pallida and G rostochiensis are the most problematic pests of the potato crop in the UK. There are no commercially available cultivars with full resistance to G. pallida and both crop rotation and granular nematicides are less effective at controlling this species than G. rostochiensis. In situations of very high PCN levels it may be possible to reduce populations and yield losses by using an autumn application of the soil fumigant 1,3-dichloropropene (1,3-D) followed by a spring application of a granular nematicide. Two field experiments were done to look at the integration of methods for the control of PCN. The Common Field experiment (G. rostochiensis infested) compared the use of 1,3-D with the granular nematicides aldicarb, oxamyl and fosthiazate when growing the susceptible cv. Estima. The Four Gates experiment (infested with both PCN species but mainly G rostochiensis) compared the performance of cv. Sante (partially resistant to G. pallida, fully resistant to G. rostochiensis) with that of the susceptible cv. Estima when treated with 1,3-D and oxamyl at full and half-rates. The results of the experiments show that an integrated approach to nematode control on heavily infested sites, including granular and fumigant nematicides and cultivar resistance, can lead to significant decreases in nematode population densities and reduce yield losses. An economic evaluation of the experiments modelled the gross margins from the different nematicide treatments. In Common Field, the highest gross margins were achieved with the combined use of fumigant and granular nematicides. In Four Gates, there was a clear economic benefit for both cultivars from the use of 1,3-D. In this experiment, oxamyl was of economic value to Estima but not to Sante and full-rate oxamyl was of more benefit than half-rate to Estima.

First record of potato cyst nematode Globodera rostochiensis in Indonesia

Abstract: Potato cyst nematode, Globodera rostochiensis, was identified for the first time in the potato-growing area of Malang, East Java, Indonesia in March 2003.

Characterisation of potato cyst nematode populations from Portugal

Abstract: Populations of potato cyst nematode (PCN) were assembled from all of the potato growing regions of Portugal, either by direct sampling of fields or from cyst samples sent to the University of Coimbra for identification. When 30 or more cysts were available, isoelectric focusing of species-specific protein bands was used to identify which PCN species were present. PCN was present in 35% of a set of 226 soil samples. PCN was also identified in a larger set of 423 populations. Of the 423 populations, 83% were pure Globodera rostochiensis, 8% were pure G. pallida and 9% were mixtures of the two. PCN was found in all of the main potato growing areas but G. pallida was not detected in Coimbra, Setubal or Viana do Castelo districts.

Early responses of resistant and susceptible potato roots during invasion by the potato cyst nematode Globodera rostochiensis

Abstract: Signals from roots of resistant (cv. Maris Piper) and susceptible (cv. Desiree) potato cultivars during inva- sion by second stage juveniles (J2s) of the potato cyst nematode, Globodera rostochiensis, were inves- tigated. Novel experimental chambers enabled the recording of electrophysiological responses from roots during nematode invasion. The root cell mem- brane potentials were maintained throughout the 3 d required to assess invasion and feeding site develop- ment. The steady-state resting membrane potentials of Desiree were more negative than those of Maris Piper on day 1, but the reverse on day 3. After 5 d there was no difference between the two cultivars. Intracellular microelectrodes detected marked spike activity in roots after the application of J2s and there were distinct and reproducible differences between the two cultivars, with the response from Desiree being much greater than that from Maris Piper. The responses to mechanical stimulation of roots by blunt micropipettes and sharp electrodes were con- sistent and similar in both cultivars to the responses in Maris Piper obtained after nematode invasion, but could not account for the marked response found in Desiree. Exogenous application of exoenzymes, used to mimic nematode chemical secretions, resulted in a distinct depolarization pattern that, although similar in both cultivars, was different from patterns obtained during nematode invasion or mechanical stimulation. The pH of homogenates prepared from roots of both cultivars was measured and a Ca 2+ channel blocker was used to assess the role of Ca 2+ in nematode invasion. The results indicated a role for Ca 2+ in the signalling events that occur during nema-

The effect of mycorrhization of potato roots on the hatching chemicals active towards the potato cyst nematodes, Globodera pallida and G. rostochiensis

Abstract: Comparison of potato root leachates (PRL) collected from the roots of mycorrhizal (using the mixed-isolate inoculum, Vaminoc) and non-mycorrhizal potato cv. Golden Wonder confirmed that mycorrhization caused a significant increase in hatching activity towards Globodera pallida but not G. rostochiensis. After fractionating the leachates by low pressure molecular exclusion/anion exchange liquid chromatography, several potato cyst nematode (PCN) species-specific hatching factors (HF) were found only in PRL from mycorrhizal plants. Leachate from mycorrhizal plants also contained more of several of those HF common to PRL from both mycorrhizal and non-mycorrhizal plants. Significantly more hatching factor stimulants (HS) active towards both PCN species were found in the PRL from mycorrhizal than from non-mycorrhizal plants; several HS were specific to mycorrhizal plants. No differences (quantitative or qualitative) were observed in hatching inhibitor (HI) levels between PRL from mycorrhizal and non-mycorrhizal plants. Mycorrhization of potato plants resulted in a 20% increase in carbon but a 48% decrease in nitrogen concentrations of the PRL compared to that from the non-mycorrhizal plants.

Separation of Globodera rostochiensis and G. pallida (Tylenchida: Heteroderidae) using morphology and morphometrics

Abstract: Two Globodera rostochiensis and two G. pallida populations (pure and mixed) were analysed by identification methods based on morphology/morphometrics. To assess the accuracy of the identification, PCR analysis was performed on the same specimens. The investigation comprised juveniles, cysts and males. Seven of the most commonly used morphological/morphometric characters were examined: stylet length, length of stylet shaft plus knobs and stylet knob shape of second-stage juveniles; number of cuticular ridges between anus and vulval basin, distance between anus and vulval basin and Granek's ratio of cysts; and spicule shape of males. Altogether, 480 specimens were analysed and assessed. There were statistically significant differences between means of the G. rostochiensis and G. pallida populations in most characters and, in part, between populations of the same species. However, no individual morphological-morphometric character proved to be discriminant for species determination as in all cases there was a large overlap. A statistical discriminant analysis showed that with our populations, the values of a commonly used table of characters for separation of the two species had to be adjusted in order to produce the break points. By judging more than one character, the identification process could be considerably improved, suggesting the possibility of designing a computerised expert system.

An integrated approach for the management of potato cyst nematodes, Globodera rostochiensis and G. pallida in India

Abstract: Field studies were conducted to investigate the effect of a plant growth promoting rhizobacterium, Pseudomonas fluorescens, neem cake, mustard intercrop and carbofuran 3 G, in different combinations, on potato cyst nematodes, Globodera rostochiensis and G. pallida, and yield of two potato cultivars viz., Kufri Jyoti and Kufri Giriraj. Higher tuber yields and lower nematode densities, in terms of number of females/2.5 cm root and number of eggs/g soil, were recorded for the cultivar Kufri Giriraj. In both of the cultivars, an application of P. fluorescens + neem cake + mustard intercrop + carbofuran 3 G increased the yield and reduced the potato cyst nematode population the most, followed by the application of P. fluorescens + neem cake + mustard intercrop, which was almost equally effective.

Effect of early blight (Alternaria solani) on healthy area duration and healthy area absorption of potatoes (Solanum tuberosum) grown in Canterbury New Zealand with different nitrogen application and stress from potato cyst nematode (Globodera rostochiensis)

Abstract: Two experiments were conducted over the 1995/96 and 1996/97 growing seasons, at Lincoln University and New Zealand Institute for Crop & Food Research, Lincoln, Canterbury to assess the effects of nitrogen and potato cyst nematode (Globodera rostocheinsis) on the development of early blight epidemics. The objective was to measure effects on photosynthetically active radiation (PAR) intercepted by crops under multiple pest constraints, and also to compare the effect of early blight, nitrogen, and potato cyst nematode on integrated values for healthy leaf area duration (HAD) and healthy leaf area absorption (HAA). Epidemic development of early blight was rapid in high nitrogen fertility plots and in plots with 30 nematode eggs/ml of soil in 1995/96, but in 1996/97 neither nitrogen nor potato cyst nematode significantly affected the epidemic development. In these trials the intercepted PAR (HAA) was derived from the integral over time of green leaf area index (GLAI) which was used as a measure of HAD...

The ability of rhizosphere bacteria isolated from nematode host and non-host plants to influence the hatch in vitro of the two potato cyst nematode species, Globodera rostochiensis and G. pallida

Abstract: Seventy bacteria, isolated from the rhizosphere of the potato cyst nematode (PCN) host plant, potato, were cultured in the presence and absence of potato root leachate (PRL) and the resultant culture filtrates were analysed for their ability to affect the hatch in vitro of the two PCN species. Of the isolates tested, nine had a significant effect on PCN hatch. Six affected Globodera pallida hatch and three affected G. rostochiensis hatch. Five of the isolates significantly increased hatch only when cultured in the presence of PRL. Three of the isolates decreased PCN hatch significantly in PRL. Only one isolate increased hatch significantly in the absence of PRL. No isolate affected the hatch of both species. Six of the nine isolates that significantly affected PCN hatch had been pre-selected by culturing on PRL. Bacterial isolates from PCN non-hosts (14 from wheat, 17 from sugar beet) were also tested for hatching activity. The principal effect of the hatch-active isolates from the PCN non-host plants was to increase PCN hatch in the presence of PRL. In contrast to the host bacteria results, the isolates from non-host plants affected only G. rostochiensis hatch (three wheat isolates and four sugar beet isolates significantly increased G. rostochiensis hatch); no such isolate affected G. pallida hatch significantly in the presence of PRL. Ten isolates (32%) from non-host plants had the ability to increase significantly the hatch of PCN in the absence of PRL (eight of these affected G. rostochiensis hatch and four affected G. pallida hatch), compared to only one bacterial isolate (1%) from a host plant. The majority of the isolates from non-hosts produced PCN species-specific effects, as with the bacteria isolated from potatoes, although two wheat isolates increased the hatch of both species significantly in the absence of PRL. Of 20 hatch-active bacterial isolates (from all three plants) identified, 70% were Bacillus spp. Other genera identified were Arthrobacter , Acinetobacter and Staphylococcus .

Some potato cyst nematode, Globodera rostochiensis and G. pallida, issues related to Swedish potato production

Abstract: The potato cyst nematodes (PCN), Globodera rostochiensis and G pallida, major parasites of potatoes, were found for the first time in Sweden in 1922 and 1965, respectively The objective of the thesis was to expand the knowledge of Swedish PCN populations by studying morphological/morphometric diversity, population genetics, virulence and biology in order to improve the control basis The most commonly used differential morphological/morphometric characters of the two PCN were examined to estimate the degree of inter- and intraspecific variation PCR analysis was performed on each specimen to ascertain the species to which it belonged An absolute separation of the species could not be achieved on the basis of individual characters, but the probability of making the right identification was substantially improved by combining two or more characters This suggested that the development of a computer expert system might be profitable The same characters as for PCN, expanded with some egg and larval dimensions, ware used to characterise a non-PCN Globodera population that might be confused with PCN Data corresponded well with the morphometry of three foreign populations of G artemisiae Identification was fortified by sequence analysis of ribosomal DNA internal transcribed spacers (ITS), whereby the first record of G artemisiae in Sweden could be established The extent of genetic polymorphism and relationship between Swedish and foreign PCN populations was estimated in an AFLP study There was a large heterogeneity in both species Swedish G pallida populations seemed to originate both in the British Isles and in continental Europe A combined method and virulence test of Swedish and foreign PCN populations proved the occurence of virulence groups Ro 1,4, Ro2,3 and Pa2,3 in Sweden The "closed container" test method appeared accurate enough for advisory samples A simplified protocol, which combines the advantages of traditional bio-tests and PCR techniques, is suggested Hatching experiments verified that G pallida is better adapted to a colder climate than G rostochiensis Populations of the latter species from early potato districts and from a northern region hatched at lower temperatures than populations from the main crop potato districts in southern Sweden, suggesting the commencement of an adaptation process

Superoxide Dismutase as a Tool for the Mulacular Identification of Plant Parasitic Nematodes.

Abstract: Superoxide dismutase (SOD) is a constitutive family of enzymes produced by all aerobic organisms. Varying amounts of SOD activity have been found at all life stages of the most diffused plant parasitic nematodes. SOD is important to aerobic metabolism and parasitism of nematodes in that it catalyzes the first step of the neutralization of the highly toxic superoxide anion (O2 •-), which is largely produced in plant-nematode incompatible reactions. SOD has also been shown to be a significant tool to diagnose root-knot, cyst-, and longidorid nematodes. A high SOD polymorphism has been revealed by Native-Page on gradient polyacrylamide gels for Meloidogyne spp. and by isoelectrofocusing for Globodera, Xiphinema and Longidorus spp. The sensitivity of such procedures has been improved by using the PhastSystem (Amersham Biosciences, Piscata, NJ, USA), an automated equipment for electrophoresis. An accurate discrimination of species of all the nematode genera tested has been achieved and an attempt was made to group populations of the Xiphinema americanum-group and to detect Globodera rostochiensis and G. pallida pathotypes.

Reaktion von Tomaten auf den Befall mit Kartoffelzystennematoden

Abstract: In Gewachshausversuchen mit der Ro1-anfalligen Tomatensorte ‘Harzfeuer’ und der Ro1-resistenten Tomatensorte ‘Sparta’ wurden in zwei Versuchsjahren die Auswirkungen des Befalls mit Globodera rostochiensis auf die Sprossentwicklung und den Ertrag untersucht. Die Auswirkungen eines Befalls von Globodera pallida auf ‘Sparta’ wurden in einem Versuchsjahr ermittelt. Neben der unverseuchten Kontrolle wurden Verseuchungsstufen von ca. 1500 und 5000 Larven/100 cm3 Boden untersucht.

Interactions between potato plants, arbuscular mycorrhizal fungi, potato cyst nematodes and a nematicide

Abstract: Inoculation of potato plants with Vaminoc, a commercial mixture of three selected isolates of arbuscular mycorrhizal fungi (AMF), and with two of these isolates, Glomus intraradices (BioRize BB-E) and Glomus mosseae (isolate BEG 12) increased the early in vitro (in potato root leachate, PRL) and in soil hatch of the potato cyst nematode (PCN) Globodera pallida (0-4 weeks after shoot emergence), but had no effect on the hatch of the other PCN species Globodera rostochiensis. In the absence of AMF, G. pallida exhibited delayed in vitro and in soil (microplants or plants grown from tubers) hatch, compared to G. rostochiensis inoculation of potato roots with AMF eliminated this delay in G. pallida hatch. While the effects of these AMF isolates on PCN hatch were consistent across a range of potato cultivars, the effect on plant growth was more variable, with certain AMF-cultivar associations being more effective than others on plant growth enhancement. The growth parameter mostly affected (increased) by mycorrhizal inoculation was root growth. When the PRL from AMF-untreated and AMF-treated plants were fractionated and corrected for carbon content, it was revealed that mycorrhizal inoculation had multiple effects on hatching factor (HF) production: generation of novel HFs (more evident with Vaminoc than with the single AMF isolates), up or down regulation of existing HFs. The result of the AMF-PCN interaction depended on the time that mycorrhizal inoculation took place: pre-inoculation with AMF 2 weeks before planting followed by one more AMF application at planting significantly lessened the multiplication of G. pallida on the roots, relative to AMF-untreated plants; in contrast, one application of AMF (at planting) increased the final G. rostochiensis population size (but not G. pallida), compared to AMF-untreated plants. In the presence of the nematicide aldicarb, the multiplication rate of G. pallida was significantly lower on roots inoculated with AMF than on roots that did not receive mycorrhizal treatment at planting.

First report of globodera pallida occurrence on the area of ukraine

Abstract: Summary Globodera pallida (Stone, 1973) and Globoderea rostochiensis (Wolenweber, 1923) are very important quarantine pests of the potato. Losses on the yield can by larger then 80 %. Diagnostics and differentiation of PCN are based on the morpholgical characteristics and of course on biological test. Now it is possible touse immunosorbent method for differentiation of Globodera pallida and G.rostochiensis and molecular biological methods, too. This work was focused on eastern part of Europe, where it had not been studied more then few populations of PCN before. The aim of these study was to make a survey of occurence of Globodera rostochiensis and Globodera pallida on area of Ukraine. Samples of PCN collected on different localities by workers of Plant Protection Servise of Ukraine. For diagnosis multiplex PCR (Zouhar et al., 2000) was used. Occurence of Globodera pallida was approved in few fields and this is first report about G. pallida in this part of Europe.