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Cyst Nematodes (cyst + nematodes)

Distribution by Scientific Domains
Life Sciences100%

Kinds of Cyst Nematodes

  • potato cyst nematodes
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    Selected Abstracts

    Two tomato ,-expansins show distinct spatial and temporal expression patterns during development of nematode-induced syncytia

    PHYSIOLOGIA PLANTARUM, Issue 3 2008
    Sylwia Fudali
    Cyst nematodes induce specific syncytial feeding structures within the root which develop from an initial cell by successive incorporation of neighbouring cells through local cell wall dissolutions followed by hypertrophy of included cells. Expansins are known to induce cell wall relaxation and extension in acidic pH, and they are involved in many processes requiring wall modification from cell expansion to cell wall disassembly. We studied the expression pattern of tomato (Lycopersicon esculentum L., cv. Money Maker) expansins during development of syncytia induced by the potato cyst nematode (Globodera rostochiensis Woll.). Based on semi-quantitative reverse transcription,polymerase chain reaction, two expansin genes, LeEXPA4 and LeEXPA5, were selected for detailed examinations because their expression was either elevated in infected roots (LeEXPA4) or specifically induced in the root upon nematode infection (LeEXPA5). Both genes have distinct spatial and temporal expression patterns that may reflect their different roles in syncytium development. LeEXPA4 transcripts were localized predominantly in parenchymatous vascular cylinder cells surrounding syncytia. This finding suggests that LeEXPA4 might be involved in cell wall disassembly or relaxation, mediating syncytium expansion and/or development of conductive tissues. By contrast, LeEXPA5 transcripts were localized in enlarging syncytial elements. Similarly, in immunogold localization experiments, polyclonal antibodies localized the LeEXPA5 protein in cell walls of syncytial elements. This expression pattern suggests that LeEXPA5 gene is specifically involved in enlargement of cells incorporated into syncytium. [source]

    Organisation of proficiency testing for plant health diagnostic tests: the experience of FAPASŪ

    EPPO BULLETIN, Issue 1 2010
    A. Reynolds
    Proficiency testing (PT) is an established quality assurance measure and is based on the comparison of laboratories' results in an inter-laboratory trial. It highlights problems in laboratory analysis and is an educational tool to help improve data quality. This article describes how PT is organised by FAPASŪ. FAPASŪ is an international PT provider (external quality assessments) for food chemistry, food microbiology, genetically modified material and water/environmental samples. Since 2007, FAPASŪ have organized plant health proficiency tests in conjunction with the Plant Pest and Disease Identification Programme at the Food and Environment Research Agency (Fera). Up until 2009, FAPASŪ has organised seven plant health proficiency tests that covered the identification of lyophilised bacteria, viruses in leaves and fungi in agar plugs. In 2009, FAPASŪ organized over 10 plant health proficiency tests under the banner of ,PhytoPAS', including Potato spindle tuber viroid, Phytophthora ramorum, Thrips palmi, Erwinia amylovora, Clavibacter michiganensis subsp. sepedonicus, etc. DNA extracts, cyst nematodes (Globodera pallida) and slides/immunofluorescence (IF) slides have been added to the programme. The organization of the plant health proficiency tests follows a similar pattern. Suitable test materials are prepared and tested for quality before distribution to requesting participants. Laboratories usually have 1,2 months to analyze their samples and return their results. A report is then compiled for issue to laboratories and these contain all results in an anonymous form, so that laboratories can compare their results with those of other participants. If a laboratory's performance is unsatisfactory then it is up to them to investigate the situation. Thus, the primary purpose of PT is the detection of inaccuracy in a laboratory's results, so that they can investigate the problems and initiate corrective procedures. [source]

    Effect of sample size on cyst recovery by flotation methods: Recommendations for sample processing during EU monitoring of potato cyst nematodes (Globodera spp.)

    EPPO BULLETIN, Issue 2 2008
    J. Bellvert
    Under EC Council Directive 2007/33/EC member states of the European Union are recommended to take soil samples ranging from 100 mL to >1500 mL to monitor populations of potato cyst nematodes [PCN] (Globodera spp.) in targeted fields. This study examines the effects of varying sample size on sample processing and cyst extraction using two widely used laboratory methods. Cyst recovery was stable using the Fenwick can from 100 mL up to the physical limits of the can. Recovery was significantly lower for low density 50 mL samples; however, this was partly due to a statistical artefact since higher numbers of cysts were lost from successively larger samples with constant cyst numbers (i.e. decreasing densities). The Schuiling centrifuge had functional limits of <100 mL and >500 mL. Outside this range, cyst recovery from low density samples was significantly reduced. Cyst recovery from samples of varying size, but with equal numbers of cysts was only constant above 100 mL. However, samples ranging from 200,500 mL were optimal for the Schuiling centrifuge. Cyst extraction efficiency was similar using both methods for samples ranging from 150 mL to 1500 mL, where larger samples were divided into <500 mL portions. However, processing times (i.e. cyst extraction and microscopic examination) and water consumption increased significantly with increasing sample size and were significantly higher when using the Fenwick can. [source]

    Relationship between saprotrophic growth in soil of different biotypes of Pochonia chlamydosporia and the infection of nematode eggs

    ANNALS OF APPLIED BIOLOGY, Issue 1 2009
    I.A. Siddiqui
    Abstract The ecology of Pochonia chlamydosporia in soil and its interaction with both plant and nematode hosts are important for the successful exploitation of the fungus as a biological control agent. Differences in saprotrophism and parasitism were assessed for biotypes of P. chlamydosporia, which had originated from the eggs of cyst or root-knot nematodes. Colonisation in soils of different textures (compost, sandy loam and loamy sand) measured by the numbers of colony-forming units, differed greatly. Most biotypes were more abundant in sterilised soil of the different textures compared with non-sterilised soils. The proportion of nematode eggs parasitised in a baiting technique demonstrated that biotypes had host preferences. Those biotypes that originated from root-knot nematodes (RKN-biotypes) infected significantly more Meloidogyne hapla eggs than Globodera pallida eggs, whereas biotypes from cyst nematodes (CN-biotypes) parasitised more G. pallida eggs than M. hapla eggs. Differences in virulence between biotypes in an in vitro assay in which the fungi were placed directly onto the egg masses of M. hapla and those differences observed in the baiting technique showed similar trends. There was a negative linear correlation between the growth of the eight biotypes in soil and the proportion of eggs they infected in compatible interactions (i.e. fungal biotype originated from the same nematode genus as the target eggs). Those biotypes that infected most nematode eggs colonised soil the least extensively, suggesting that virulence may have a fitness cost. However, the relationship between saprotrophic growth and virulence is complex. The relative abundance of the different biotypes in soil in Petri dish assays was similar to that under glasshouse conditions using potato but not tomato as the plant host. Chlamydospores of some biotypes applied to soil significantly reduced (>50%) the population densities of M. hapla on tomato and of G. pallida on potato plants. Some biotypes that were both effective and virulent are good candidates for biological control of specific nematode pests. Data presented here and elsewhere indicate that RKN-biotypes have different host preferences to CN-biotypes; the specific primers based on the vcp1 gene from P. chlamydosporia rapidly confirmed the host origin of seven of the eight biotypes. [source]

    Glyphosate applied to genetically modified herbicide-tolerant sugar beet and ,volunteer' potatoes reduces populations of potato cyst nematodes and the number and size of daughter tubers

    ANNALS OF APPLIED BIOLOGY, Issue 3 2000
    A M DEWAR
    Summary Glyphosate, applied early or later or twice to genetically modified glyphosate-tolerant sugar beet, gave excellent control of planted ,volunteer' potatoes growing within the crop compared to conventional herbicide programmes with or without clopyralid. In three out of four trials, this resulted in significant reductions in the numbers of eggs and cysts of potato cyst nematodes (Globodera rostochiensis and G. pallida) where infestations were moderate (23,89 eggs g,1 soil). In the fourth trial, which had very high initial populations (130 eggs ,1 soil), none of the herbicide treatments had any significant effect on numbers of nematode eggs or cysts. This was probably due to competition for feeding sites, and the early death of the potatoes in all treatments caused by feeding damage by the nematodes and infection by blight, which prevented the nematodes from completing their life cycle. Glyphosate also significantly reduced the number and size of daughter tubers produced, thus helping to prevent a further volunteer problem in the next crop in the rotation. This was achieved by one or two applications of one chemical compared to 2,5 applications of cocktails of conventional herbicides. [source]