Academic literature on the topic 'Nematode'
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Journal articles on the topic "Nematode"
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Irvine, Allister, Sharon A. Huws, Louise E. Atkinson, and Angela Mousley. "Exploring the antimicrobial peptidome of nematodes through phylum-spanning in silico analyses highlights novel opportunities for pathogen control." PLOS Neglected Tropical Diseases 17, no. 9 (September 6, 2023): e0011618. http://dx.doi.org/10.1371/journal.pntd.0011618.
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Antimicrobial Peptides (AMPs) are key constituents of the invertebrate innate immune system and provide critical protection against microbial threat. Nematodes display diverse life strategies where they are exposed to heterogenous, microbe rich, environments highlighting their need for an innate immune system. Within the Ecdysozoa, arthropod AMPs have been well characterised, however nematode-derived AMP knowledge is limited. In this study the distribution and abundance of putative AMP-encoding genes was examined in 134 nematode genomes providing the most comprehensive profile of AMP candidates within phylum Nematoda. Through genome and transcriptome analyses we reveal that phylum Nematoda is a rich source of putative AMP diversity and demonstrate (i) putative AMP group profiles that are influenced by nematode lifestyle where free-living nematodes appear to display enriched putative AMP profiles relative to parasitic species; (ii) major differences in the putative AMP profiles between nematode clades where Clade 9/V and 10/IV species possess expanded putative AMP repertoires; (iii) AMP groups with highly restricted profiles (e.g. Cecropins and Diapausins) and others [e.g. Nemapores and Glycine Rich Secreted Peptides (GRSPs)] which are more widely distributed; (iv) complexity in the distribution and abundance of CSαβ subgroup members; and (v) that putative AMPs are expressed in host-facing life stages and biofluids of key nematode parasites. These data indicate that phylum Nematoda displays diversity in putative AMPs and underscores the need for functional characterisation to reveal their role and importance to nematode biology and host-nematode-microbiome interactions.
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Haegeman, Annelies, John T. Jones, and Etienne G. J. Danchin. "Horizontal Gene Transfer in Nematodes: A Catalyst for Plant Parasitism?" Molecular Plant-Microbe Interactions® 24, no. 8 (August 2011): 879–87. http://dx.doi.org/10.1094/mpmi-03-11-0055.
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The origin of plant parasitism within the phylum Nematoda is intriguing. The ability to parasitize plants has originated independently at least three times during nematode evolution and, as more molecular data has emerged, it has become clear that multiple instances of horizontal gene transfer (HGT) from bacteria and fungi have played a crucial role in the nematode's adaptation to this new lifestyle. The first reported HGT cases in plant-parasitic nematodes were genes encoding plant cell wall–degrading enzymes. Other putative examples of HGT were subsequently described, including genes that may be involved in the modulation of the plant's defense system, the establishment of a nematode feeding site, and the synthesis or processing of nutrients. Although, in many cases, it is difficult to pinpoint the donor organism, candidate donors are usually soil dwelling and are either plant-pathogenic or plant-associated microorganisms, hence occupying the same ecological niche as the nematodes. The exact mechanisms of transfer are unknown, although close contacts with donor microorganisms, such as symbiotic or trophic interactions, are a possibility. The widespread occurrence of horizontally transferred genes in evolutionarily independent plant-parasitic nematode lineages suggests that HGT may be a prerequisite for successful plant parasitism in nematodes.
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Gdemakarti, Yoshua, Bainah Sari Dewi, I. Gede Swibawa, and Irwan Sukri Banuwa. "KOMUNITAS NEMATODA TANAH DI BLOK LINDUNG HUTAN PENDIDIKAN KONSERVASI TERPADU TAMAN HUTAN RAYA WAN ABDUL RACHMAN." Jurnal Hutan Tropis 9, no. 1 (April 18, 2021): 13. http://dx.doi.org/10.20527/jht.v9i1.10464.
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Hutan Pendidikan Konservasi Terpadu (HPKT) is part of Taman Hutan Raya Wan Abdul Rachman (Tahura WAR) enabled to support educational activities and research. The quality of the soil in this area is influenced by several factors, one of the factors i.e. nematodes. The aim of study to know the community of nematodes on the Protection Block, Hutan Pendidikan Konservasi Terpadu, Wan Abdul Rachman Forest Park. The research was conducted in April to May 2018. The soil samples were taken on arboretum seven, arboretum eight, arboretum nine and arboretum 10. Nematode observations were conducted in the laboratory of Plant Pests, Faculty of Agriculture, University of Lampung. Nematodes have been identified to genus level based on morphological traits. The result of study showed that there are 29 genus of nematode consists of 17 plant parasitic nematode genera, seven nematoda bacterial-feeding, three nematode fungal-feeding, one omnivore nematode and one predator nematode. The dominant nematode genera are Criconomella, Helycotylenchulus dan Rotylenchulus. The abundance of nematodes ranges from 251-613 individuals / 300cc soil. The diversity of soil nematodes based on the Shannon-Wienner index ranges from 2.33-2.62. The Shannon-Whienner Index criteria are classified as moderate. The Simpson Index ranges from 0.862-0.907. The highest similarity index genus in arboretum seven with arboretum nine and arboretum eight with arboretum nine with a value of 0.81. The lowest in arboretum seven and arboretum 10 that is 0.63.
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Grewal, Parwinder S., Edwin E. Lewis, and Sudha Venkatachari. "Allelopathy: a possible mechanism of suppression of plant-parasitic nematodes by entomopathogenic nematodes." Nematology 1, no. 7 (1999): 735–43. http://dx.doi.org/10.1163/156854199508766.
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Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.
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Indarti, Siwi, Arif Wibowo, Siti Subandiyah, and Miftahul Ajri. "First Record: A Stem and Bulb Plant Parasitic Nematode at Garlic Area Centre Temanggung, Central Java, Indonesia with Species Reference to Ditylenchus dipsaci." Jurnal Perlindungan Tanaman Indonesia 22, no. 2 (November 15, 2018): 233. http://dx.doi.org/10.22146/jpti.35321.
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A survey to investigate the stem and bulb plant parasitic nematode at one of garlic area centre, in Temanggung, Central Java, Indonesia was conducted from Januaryto February 2018. Infected plant with specific symptoms, morphological and morphometric characters both of female and male of adult nematodes were used to describe a A1 quarantine plant parasitic nematode Ditylenchus dipsaci. Seven from nine observed locations were postively infected with population in average 2.67 nematodes per 100 g of soil and 2.67–189.33 per bulb. This is the first report of D. dipsaci from Indonesia and consequently further investigations were needed to know their distribution and also to confirm the origin of the nematode. IntisariSurvei keberadaan nematoda parasit batang dan umbi dilakukan pada bulan Januari–Februari 2018 pada satu sentra penangkaran bawang putih di Temanggung, Jawa Tengah, Indonesia. Tanaman terinfeksi dengan gejala serangan yang spesifik, karakter morfologi dan morfometri nematoda betina dan jantan dewasa dipergunakan dalam identifikasi Ditylenchus dipsaci yang merupakan nematoda parasit tanaman yang termasuk OPTK A1 (Organisme Pengganggu Tanaman Karantina A1) di Indonesia. Sebanyak tujuh dari sembilan lokasi yang diamati mengindikasikan positif sebagai daerah sebaran nematoda tersebut dengan populasi rata-rata 2,67 ekor per 100 gram tanah dan 2,67–189,33 nematoda per umbi. Laporan pertama tentang nematoda D. dipsaci ini membawa konsekuensi perlunya penelitian lebih lanjut untuk mengetahui daerah sebaran dan juga konfirmasi dari mana nematoda tersebut berasal.
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Ono, Masaya, Yoichi Hayakawa, and Toyoshi Yoshiga. "Bacterial feeding nematodes ingest haemocytes in the haemocoel of the insect Galleria mellonella." Parasitology 147, no. 3 (November 18, 2019): 279–86. http://dx.doi.org/10.1017/s0031182019001550.
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AbstractInsect parasitic nematodes have acquired mechanisms to evade their host immune response for successful parasitism. Despite the importance of understanding of the evolution of evasion mechanisms from host immunity, insect immune response against non-parasitic nematodes has not been well studied. In our previous study, we demonstrated that a non-insect parasitic nematode Caenorhabditis elegans was not encapsulated by haemocytes in the larvae of the greater wax moth Galleria mellonella. To understand how nematodes influence insect haemocytes to escape encapsulation, we examined the effect of C. elegans on haemocytes in the haemocoel of G. mellonella larvae. Injection of nematodes resulted in the decrease of haemocyte density while mortality and spreading ability of haemocytes, the haematopoietic organs were not affected. In vitro co-incubation of haemocytes with nematodes resulted in a decrease of haemocyte density and we observed feeding on haemocytes by nematodes. Injection of C. elegans feeding-delay mutants into insects did not cause the decrease of haemocyte density. The decrease of haemocyte density was due to the nematode's ingestion of haemocytes. Furthermore, an entomopathogenic nematode and other bacterial feeding nematodes also showed similar feeding behaviour. The nematode's ability to feed on haemocytes may have played an important role in the evolution of nematode parasitism in bacterial-feeding nematodes.
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Reyes-Torres, Limarie Judith, Yazminne Meléndez-Torres, and Alonso Ramírez. "Ocurrencia de nemátodos en ninfas de Ephemeroptera en una quebrada de bosque tropical lluvioso." Intropica 11 (December 21, 2016): 67. http://dx.doi.org/10.21676/23897864.1863.
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Nematodes are common symbionts of aquatic insects. Here, we assessed the presence of nematodes in mayfly nymphs (Ephemeroptera), evaluated their prevalence in the population, and determined factors associated with nematode presence. Mayflies were collected (n = 130) from three stream habitats (riffles, pools, and boulders) using a D net, in Prieta stream, El Verde Field Station, Puerto Rico. Mayflies were dissected and nematode presence was determined under a light microscope (4 x and 10 x). Nematode prevalence was 50 %. Nematodes were not identified beyond Phylum level, but we were able to eliminate various groups as infective agents (Nematoda: Mermithidae and Nematomorpha: Gordiida). They were mostly found in the abdomen, head or thorax of mayflies. There were differences in infection among taxa, Neohagenulus was the group with the highest proportion of infection. Mayfly body shape, feeding strategy, or activity potentially explain differences in infection among taxa. There were no differences in infection among habitats, but mayflies were less abundant in riffles; and there was no relation between mayfly body length and the number of nematodes present. To our knowledge, this is the first report of a nematode present in mayfly nymphs in Puerto Rico.
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Panjerrino, Yoshua Gdemakarti, Bainah Sari Dewi, and I. Gede Swibawa. "Diversity of Soil Nematode in Utilization Block Integrated Educational Conservation Forest, Wan Abdul Rachman Great Forest Park." Jurnal Sylva Lestari 7, no. 2 (June 18, 2019): 214. http://dx.doi.org/10.23960/jsl27214-224.
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Change of land forest in Wan Abdul Rachman Forest Park became agroforestry, affect of cover condition and decrease the content of soil matter. Nematode was one of the soils biotas that can be used as an indicator of change in the soil status. The aim of study is to know the community and diversity of nematodes on the Utilization Block, Integrated Educational Conservation Forest, Wan Abdul Rachman Great Forest Park. The research was conducted in April to May 2018. The soil samples were taken on arboretum one, arboretum two, arboretum three and arboretum four in Integrated Educational Conservation Forest, Wan Abdul Rachman Great Forest Park. Nematode observations were conducted in the Plant Pests Laboratory, Faculty of Agriculture, University of Lampung. Nematodes was identified to genus level based on morphological traits. The analysis used were including the index of diversity, dominance and similarities between genus arboretum. The results showed that there were 30 genus of nematode consists of 19 plant parasitic nematode genera, six nematoda bacterial-feeding, three nematode fungal-feeding and two predator nematodes. The dominant nematode genera were Criconomella, Helycotylenchulus and Rotylenchulus. The abundance of nematodes ranges from 171-617 individuals/300cm3 soil. The diversity of soil nematodes based on the Shannon-Wienner index ranges from 2,47 – 2,80. The Shannon-Whienner Index criteria were classified as moderate. The Simpson Index ranges from 0,89 – 0,93. The highest similarity index genus in arboretum three and four with a value of 0,81 and the lowest in arboretum two and three which is 0,54. Key words: nematodes community, Integrated Educational Conservation Forest, Wan Abdul Rachman Great Forest Park
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Bird, A. F. "The influence of the actionmycete,Pasteuria penetrans, on the host–parasite relationship of the plant-parasitic nematode,Meloidogyne javanica." Parasitology 93, no. 3 (December 1986): 571–80. http://dx.doi.org/10.1017/s0031182000081270.
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SUMMARYThe actinomycete,Pasteuria penetrans, is a specific endoparasite of various plant-parasitic nematodes. When parasitizing the root-knot nematode (Meloidogyne javanical) the nematode's capacity to reproduce is destroyed and feeding on and stimulation of the plant host are unaffected even though the bulbous body of the female nematode becomes filled with spores. Parasitism by the actinomycete does not alter the rate of growth in the early stages of nematode development although the non-parasitized female grows more rapidly than the parasitized one for a short time immediately after the final moult.Pasteuriadid not invade or inactivate the anterior oesophageal region of the femaleMeloidogyneor influence the morphology of the giant cells induced by these nematodes in their hosts' roots. The influence of this parasite on the developmental physiology of its nematode host is discussed.
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Malyutina. "ABOUT EFFECTS OF SOME NEUROPEPTIDES ON LOCOMOTOR BEHAVIOR OF CYST-FORMING PLANT NEMATODES." THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL, no. 21 (May 29, 2020): 213–16. http://dx.doi.org/10.31016/978-5-9902341-5-4.2020.21.213-216.
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The article presents an analysis of world literature on the study of the physiological and functional significance of FMRFamide-like neuropeptides in the neurobiology of cyst-forming plant parasitic nematodes (by the example of larvae of the 2-yearold potato cyst nematode Globodera pallida and G. rostochiensis, and soybean cyst nematode Heterodera glycines). It was shown that the basic physiological and functional characteristics of FMRFamide-like neuropeptides were obtained from the effects that have some neuropeptides on the motor activity of intact nematode larvae, and molecular studies of flp-genes that encode FMRFamidelike neuropeptides. FMRFamide-like neuropeptides belong to the largest and most diverse family of signal neuropeptides found in invertebrate animals including numerous representatives of the Nematoda type which can significantly modulate the locomotor behavioral reactions of these animals. The work discusses a physiological function of FMRFamide-like neuropeptides and the identified putative receptor of one of the neuropeptides in locomotor behavioral reactions that ensure the vital activity of cyst-forming nematodes, and the possibility of using the data in developing new targeted anthelmintics. The fact of revealing the peptidergic nervous system in cyst-forming plant nematodes, parasitic nematodes of vertebrate animals and freeliving nematodes confirms the concept about the conservation of the peptidergic nervous system in representatives of the entire Nematoda type in general.
Dissertations / Theses on the topic "Nematode"
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Farr, C. R. "Nematocide Comparisons for Rootknot Nematode Control." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219774.
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The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.Preplant treatments for rootknot nematodes on sandy loam gave less yield response than in earlier years at the same Buckeye field location. Post emergence treatments on sandy loam at Waddell failed to give sufficient economic return even though lateral root infestation level was over 50 percent.
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Valadas, Vera Mónica Piegas. "Genetic diversity of entomopathogenic nematodes (Nematoda: Steinernematidae and Heterorhabditidae) and the nematode Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) from continental Portugal." Doctoral thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/15718.
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“Diversidade genética dos nemátodes entomopatogénicos
(Nematoda: Steinernematidae e Heterorhabditidae) e do
nemátode Bursaphelenchus xylophilus (Nematoda:
Aphelenchoididade) em Portugal continental”
Os nematodes entomopatogénicos são utilizados como agentes de controlo
biológico. Para compreender a sua diversidade, foi realizada uma prospecção
em Portugal. Cinco espécies, nomeadamente Steinernema feltiae, S.
intermedium, S. kraussei, Steinernema sp. e Heterorhabditis bacteriophora
foram identificadas. As sequências de ITS, região D2D3 do 28S rRNA, COXI e
cytb foram utilizadas para estudar a diversidade genética das duas espécies
mais abundantes, S. feltiae and H. bacteriophora, não tendo sido encontradas
diferenças significativas entre isolados.
O nemátode da madeira do pinheiro, Bursaphelenchus xylophilus, provoca
doença nos pinheiros tendo sido detectada pela primeira vez na Europa e em
Portugal em 1999. Para avaliar a diversidade genética dos isolados
Portugueses e identificar o padrão de propagação da doença, foram utilizadas
a sequência da região IGS do 5.8S rRNA, e os genes cytb e cellulase,
combinados com os padrões ISSR. Os padrões de ISSR mostraram elevada
diversidade genética entre os recentes isolados Portugueses, sugerindo a
possibilidade de uma nova introdução. As árvores filogenéticas dos genes da
celulase e cytb sugeriram uma origem Asiática para os isolados Portugueses; ABSTRACT: Entomopathogenic nematodes are used as biocontrol agents. To understand
their diversity, a survey was undertaken in Portugal. Five species, namely
Steinernema feltiae, S. intermedium, S. kraussei, Steinernema sp. and
Heterorhabditis bacteriophora were identified. The ITS, 28S rRNA D2D3 region,
COXI and cytb sequences, used to study the genetic diversity of the two most
abundant species, S. feltiae and H. bacteriophora, showed no significant
differences among the isolates.
Bursaphelenchus xylophilus causes severe disease in pine trees and was
detected for the first time in Europe and in Portugal in 1999. To evaluate the
genetic diversity of Portuguese isolates and identify disease spread pathways,
the sequence of 5.8S rRNA IGS region, cytb and cellulase genes, combined
with ISSR fingerprints were used. ISSR fingerprints show a high genetic
variability among recent Portuguese isolates, suggesting the possibility of a new
introduction. Phylogenetic trees based on cellulase and cytb genes suggests an
Asian origin for Portuguese isolates.
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Olsen, Mary W. "Root-knot nematode." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2011. http://hdl.handle.net/10150/146969.
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3 pp.Originally published: 2000
Nematodes are microscopic round worms found in many habitats. They are the most abundant multicellular organisms on earth. Most are beneficial memebers of their ecosystems, but a few are economic parasites of plants and animals. There are several plant parasitic nematodes that cause problems on landscape and garden plants in Arizona and the most widespread and economically important are the root-knot nematodes. This article discusses the hosts and environmental conditions, symptoms and disease of root-knot nematode, and the prevention / control method to it.
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Viketoft, Maria. "Soil nematode communities in grasslands : effects of plant species identity and diversity /." Uppsala : Dept. of Ecology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200748.pdf.
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Shrestha, Roshi. "A physiological and genetic mapping study of tolerance to root-knot nematode in rice." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=24807.
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Kikuchi, Taisei. "Studies on nematode parasitism genes of the pine wood nematode Bursaphelenchus xylophilus." Kyoto University, 2006. http://hdl.handle.net/2433/136647.
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Nunn, Gary B. "Nematode molecular evolution : an investigation of evolutionary patterns among nematodes based upon DNA sequences." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334855.
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Hrabok, Jackie T. "Nematode parasites of reindeer in Fennoscandia : population dynamics, anthelmintic control and its environmental impact /." Uppsala : Dept. of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200689.pdf.
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Kumar, Sujai. "Next-generation nematode genomes." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7609.
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The first metazoan to be sequenced was a nematode (Caenorhabditis elegans), and understanding the genome of this model organism has led to many insights about all animals. Although eleven nematode genomes have been published so far and approximately twenty more are under way, the vast majority of the genomes of this incredibly diverse phylum remain unexplored. Next-generation sequencing has made it possible to generate large amounts of genome sequence data in a few days at a fraction of the cost of traditional Sanger-sequencing. However, assembling and annotating these data into genomic resources remains a challenge because of the short reads, the quality issues in these kinds of data, and the presence of contaminants and co-bionts in uncultured samples. In this thesis, I describe the process of creating high quality draft genomes and annotation resources for four nematode species representing three of the five major nematode clades: Caenorhabditis sp. 5, Meloidogyne floridensis, Dirofilaria immitis, and Litomosoides sigmodontis. I describe the new approaches I developed for visualising contamination and co-bionts, and I present the details of the robust workflow I devised to deal with the problems of generating low-cost genomic resources from Illumina short-read sequencing. Results: The draft genome assemblies created using the workflow described in this thesis are comparable to the draft nematode genomes created using Sanger sequencing. Armed with these genomes, I was able to answer two evolutionary genomics questions at very different scales. The first question was whether any non-coding elements were deeply conserved at the level of the whole phylum. Such elements had previously been hypothesised to be responsible for the phylum body plan in vertebrates, insects, and nematodes. I used twenty nematode genomes in several whole-genome alignments and concluded that no such elements were conserved across the whole phylum. The second question addressed the origins of the highly destructive plant-parasitic root-knot nematode Meloidogyne incognita. Comparisons with the newly sequenced Meloidogyne floridensis genome revealed the complex hybrid origins of both species, undermining previous assumptions about the rarity of hybrid speciation in animals. Conclusions: This thesis demonstrates the role of next-generation sequencing in democratising genome sequencing projects. Using the sequencing strategies, workflows, and tools described here, one can rapidly create genomic resources at a very low cost, even for unculturable metazoans. These genomes can be used to understand the evolutionary history of a genus or a phylum, as shown.
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Jordan, Katerina Serlemitsos. "The ecology of plant-parasitic nematodes and their antagonists on golf course greens turf in southern New England /." View online ; access limited to URI, 2005. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3188061.
Full textBooks on the topic "Nematode"
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Wajid, Khan M., ed. Nematode interactions. London: Chapman & Hall, 1993.
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Smith, Kirk A. Entomopathogenic nematode bibliography: Heterorhabditid and Steinernematid nematodes. Fayetteville, Ark: Arkansas Agricultural Experiment Station, 1992.
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Plant nematode control. Oxon, UK: CAB International, 1998.
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D, Griffin G., Roberts Philip A, and Utah Agricultural Experiment Station, eds. Quantifying nematode control. Logan, Utah: Utah Agricultural Experiment Station, Utah State University, 1990.
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R, Barker Kenneth, Pederson Gary A, Windham Gary L, American Society of Agronomy, Crop Science Society of America., and Soil Science Society of America., eds. Plant and nematode interactions. Madison, Wis: American Society of Agronomy, 1998.
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V, Volkova T., ed. Paraziticheskie nematody rasteniĭ i͡u︡ga Dalʹnego Vostoka. Vladivostok: DVO AN SSSR, 1988.
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Gaugler, R., and A. L. Bilgrami, eds. Nematode behaviour. Wallingford: CABI, 2004. http://dx.doi.org/10.1079/9780851998183.0000.
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Khan, M. Wajid, ed. Nematode Interactions. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1488-2.
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Randy, Gaugler, and Bilgrami Anwar L. 1956-, eds. Nematode behaviour. Wallingford, Oxfordshire, UK: CABI Pub., 2004.
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H, Brown R., and Kerry B. R, eds. Principles and practice of nematode control in crops. Sydney [N.S.W.]: Academic Press, 1987.
Find full textBook chapters on the topic "Nematode"
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Helder, Johannes, and Holger Heuer. "Let's be inclusive - the time of looking at individual plant parasitic nematodes is over, and new technologies allow for it." In Integrated nematode management: state-of-the-art and visions for the future, 403–7. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247541.0056.
Full textAbstract:
Abstract Parasitism is a popular life style among members of the phylum Nematoda. Around 46% of the 27,000 described nematode species use either a plant or an animal as a primary food source. Molecular phylogenetics has aided in deciphering patterns of evolution and diversification among plant parasitic nematodes. Alignments comprising over 5000 nearly full-length small subunit ribosomal DNA sequences (each approximately 1700 bp) with a fairly good coverage of all extant nematode families allowed to pinpoint patterns with regard to the appearance of plant parasitism. This chapter describes the soil biome, identification of nematode and microbial community in soil, as well as the activity of microbiome. Future plant parasitic nematode management strategies are also mentioned. Exploring and boosting the soil suppressive potential will be a major additional tool in the foreseeable future.
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Haque, Ziaul, and Mujeebur Rahman Khan. "Introduction." In Handbook of invasive plant-parasitic nematodes, 1–17. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247367.0001.
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Abstract This chapter introduces some plant-parasitic nematodes and discusses their agricultural importance. It describes nematode diversity and the effects of global agricultural trade on nematode spread. It defines invasive plant-parasitic nematodes and presents the assessment criteria for a nematode as an invasive species. Invasiveness ratings (scores) are proposed for categorizing low, medium and highly invasive nematodes. Tabulated data are also given on crop losses caused by plant-parasitic nematodes to different agricultural crops.
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Sikora, Richard A., Jon Padgham, and Johan Desaeger. "The unpredictability of adapting integrated nematode management to climate variability." In Integrated nematode management: state-of-the-art and visions for the future, 463–71. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247541.0064.
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Abstract The areas of concern regarding the future importance of climate change and variability on nematode damage and integrated management include: shifts in the distribution of nematodes, stimulation of additional generations, increased reproductive potential, development of more severe nematode-pathogen complexes, inability to monitor with remote sensing populations over multiple seasons, negative yield due to nematodes and reduced soil moisture levels, adapting integrated nematode management (INM) to highly volatile interannual fluctuations, loss of organic matter and soil antagonistic potential, lack of an effective in-season plant curative pesticide, enhancement of cumulative multi-species impact, and inactivation or loss of plant resistance to nematodes. This chapter reflects on some of the above points and how long-term climate change and increasing climate variability may impact nematodes, crop losses and potential modification of INM under climate change induced risk. It discusses climate change and climate variability in the context of INM, climate impacts on agricultural crops, critical climate change hotspots, climate influence on nematode biological processes, and the use of degree-days to monitor temperature effects on nematode development. The use of plant parasitic nematodes as research models and immediate priorities for improved near-term climate risk management within INM are also described.
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Höss, Sebastian. "Single- and multi-species toxicity testing with nematodes." In Ecology of freshwater nematodes, 298–322. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789243635.0010.
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Abstract This chapter discusses the utility of nematodes in experimental ecotoxicology, and specifically in the study of freshwaters. Drawing on reports in which nematodes were used as test organisms in single-species tests as well as studies investigating nematode communities in model ecosystems (i.e. microcosms), the suitability of nematode-based experimental approaches in prospective and retrospective risk assessments of chemicals in freshwater sediments is examined. Several examples are presented of the use of Caenorhabditis elegans as a test organism in single-species bioassays, in order to demonstrate the versatility of this nematode for ecotoxicological investigations.
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Peng, De-liang. "Status of soybean cyst nematodes and integrated management in China." In Integrated nematode management: state-of-the-art and visions for the future, 111–16. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247541.0016.
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Abstract This chapter focuses on the host range, geographical distribution, economic importance, damage symptoms and biology and life cycle of the soyabean cyst nematode Heterodera glycines in China. Some information on their interactions with other nematodes and pathogens, efficacy and optimization of some recommended integrated nematode management systems and future outlook and research requirements for nematode management strategies are also presented.
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Prasad, Jonnalagadda S., and Nethi Somasekhar. "The unseen rice root nematode problem in irrigated rice." In Integrated nematode management: state-of-the-art and visions for the future, 61–65. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247541.0009.
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Abstract This chapter focuses on the economic importance, host range, geographical distribution, damage symptoms and biology and life cycle of Hirschmanniella oryzae and H. mucronata, the dominant nematode species infecting rice crops in India. The interactions of these pests with other nematodes and pathogens, the efficacy of some recommended integrated nematode management strategies and future developments in Indian nematode control are also discussed.
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Owen, Kirsty. "A triumph of tolerance: managing the threat to wheat production by the root lesion nematode Pratylenchus thornei in the subtropical grain region of eastern Australia." In Integrated nematode management: state-of-the-art and visions for the future, 13–19. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247541.0002.
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Abstract This chapter provides information on the economic importance, host range, geographical distribution, damage symptoms, biology and life cycle and interactions with other nematodes and pathogens of the root lesion nematode, Pratylenchus thornei, a severe and widespread threat to wheat production in the subtropical grain production region of eastern Australia. Some recommended integrated nematode management practices and future research for nematode resistance breeding are also presented.
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Viaene, Nicole, Johannes Hallmann, and Leendert P. G. Molendijk. "Methods for nematode extraction." In Techniques for work with plant and soil nematodes, 12–41. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781786391759.0012.
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Abstract Nematodes can be present in different matrices. This chapter describes several methods to extract nematodes from soil and plant parts. It is crucial that an appropriate method is chosen for the purpose of the research as different types of nematodes, and even different nematode stages, are extracted depending on the method. Factors to consider for choosing the optimal extraction method are the extraction efficiency of the method, the maximum sample size that can be analysed and costs of the extraction equipment. In addition, water consumption, labour and the time needed before nematodes can be examined can be important factors.
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Viaene, Nicole, Johannes Hallmann, and Leendert P. G. Molendijk. "Methods for nematode extraction." In Techniques for work with plant and soil nematodes, 12–41. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781786391759.0002.
Full textAbstract:
Abstract Nematodes can be present in different matrices. This chapter describes several methods to extract nematodes from soil and plant parts. It is crucial that an appropriate method is chosen for the purpose of the research as different types of nematodes, and even different nematode stages, are extracted depending on the method. Factors to consider for choosing the optimal extraction method are the extraction efficiency of the method, the maximum sample size that can be analysed and costs of the extraction equipment. In addition, water consumption, labour and the time needed before nematodes can be examined can be important factors.
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Soares, Pedro Luiz Martins, and Daniel Dalvan Nascimento. "Integrated nematode management of root lesion and root-knot nematodes in soybean in Brazil." In Integrated nematode management: state-of-the-art and visions for the future, 103–10. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789247541.0015.
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Abstract This chapter focuses on the economic importance, host range, geographical distribution, damage symptoms and biology and life cycle of root lesion and root-knot nematodes infesting soyabean in Brazil, i.e. Pratylenchus brachyurus, Meloidogyne javanica and M. incognita. Some information on their interactions with other nematodes and pathogens, efficacy and optimization of some recommended integrated nematode management strategies and future outlook and research requirements for nematode management are also presented.
Conference papers on the topic "Nematode"
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Niu, Haoyu, Andreas Westphal, and YangQuan Chen. "A Contactless Classification Method for Early Detection of Nematodes Using Deep Neural Networks (DNNs) and TensorFlow." In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-68557.
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Abstract Soil-borne plant-parasitic nematodes are microscopic, eellike roundworms. The root-knot nematodes (Meloidogyne spp.) and root-lesion nematodes (Pratylenchus vulnus) are among the most damaging in California, which are difficult to control and can spread easily in soil on tools, boots, and infested plants. Root-knot nematodes can attack many different crops, including nut and fruit trees, usually cause unusual swellings, called galls, on affected plants’ roots. It is not easy to recognize the infestations of these nematodes. For instance, researchers need to dig up walnut trees with symptoms, wash or gently tap the soil from the roots, and examine the roots for galls. The nematode extraction procedures, identification, and enumeration under a microscope are tedious and time-consuming. Therefore, in this article, the authors proposed to use a low-cost contactless radio frequency tridimensional sensor “Walabot,” and Deep Neural Networks (DNNs), to perform the early detection of nematodes in a walnut site. Radiofrequency reflectance of walnut leaves from different nematode infestation levels was measured. The hypothesis was that waveforms generated from walnut leaves can estimate the damage caused by nematodes. DNNs with Tensor-Flow were used to train and test the proposed method. Results showed that the Walabot predicted nematode infestation levels with an accuracy of 82%, which showed great potentials for early detection of nematodes.
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Sasanelli, Nicola, Ion Toderas, Elena Iurcu-Straistaru, Stefan Rusu, Varvara Migunova, and Alena Konrat. "Yield losses caused by plant parasitic nematodes graphical estimation." In International symposium ”Functional ecology of animals” dedicated to the 70th anniversary from the birth of academician Ion Toderas. Institute of Zoology, Republic of Moldova, 2019. http://dx.doi.org/10.53937/9789975315975.60.
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Curves for graphical estimation of yield losses caused by plant parasitic nematodes were calculated on the basis of the relationship between soil nematode population density and damage to plants as described by the Seinhort’s equation y = m + (1 – m) z(P-T). By a logarithmic transformation this equation was transformed as y = m + (1 – m) 1.05[(P/-T) + 1] and solved considering values of tolerance limit (T) and the minimum relative yield (m) from the literature. The obtained curves that can be defined “Curves of nematode-pathogenicity” allow a quick and easy evaluation of yield losses for each known crop-nematode relationship.
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Renčo, Marek, Andrea Čerevková, and Nicola Sasanelli. "Effects of invasive japanese knotweed on diversity and structure of soil nematode communities." In Xth International Conference of Zoologists. Institute of Zoology, Republic of Moldova, 2021. http://dx.doi.org/10.53937/icz10.2021.43.
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In this study we investigated the communities of soil nematodes in the forest habitats invaded and uninvaded by Fallopia japonica (Houtt.) Ronse Decr., in Tatra National Park, Slovakia. We found that invasion by F. japonica altered nematode communities and their structures. Total nematode abundance, species number and nematode biomass were significantly lower in invaded than uninvaded plots, but species diversity remained unaffected throughout the study. The overall abundance of all nematode trophic groups well represented the negative impact of F. japonica invasion on soil food webs, supported by low values of all maturity indices, a structural index and the Jaccard index of faunal similarity. A weighted faunal analysis similarly characterized the food webs of invaded plots as poorly developed or highly disturbed, with bacterial decomposition and a low C/N ratio. Our findings thus suggest that dense plots of knotweed simplify the structural complexity of the soil environment by reducing the richness of plant species, which may have contributed to the negative changes in the structures of the nematode communities.
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Sasanelli, Nicola, Ion Toderas, Elena Iurcu-Straistaru, Stefan Rusu, Alexei Bivol, Olesea Gliga, and Trifone D'Addabbo. "Sustainable agriculture in the light of climate change: effect of temperatures and exposure times on the mortality of the dagger nematode Xiphinema index." In Scientific International Symposium "Plant Protection – Achievements and Perspectives". Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2023. http://dx.doi.org/10.53040/ppap2023.73.
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The gradual rising of average temperatures due to climate change are increasing the problem caused by phytoparasitic nematodes. To predict the effect of soil solarization on Xiphinema index, an experiment was undertaken to investigate the effect of different temperatures (from 25 to 42.5 °C) and exposure times (from 2 up to 2,048 hrs) on the mortality of the nematode. Surviving nematodes were expressed as percentages of those surviving at 25 °C. The differences to 100 were considered as mortality percentages. To kill 50% of nematode population were necessary 180, 34, 4.7 and 2.5 hours at 35, 37.5, 40 and 42.5 °C, respectively. Data fitted the model Pt=Po10-Δt/(q+mT) reported in literature.
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Malyutina, T. A. "NEUROPEPTIDES INVOLVING IN THE REGULATION OF LOCOMOTOR BEHAVIOR OF ROOT-KNOT PLANT-PARASITIC NEMATODES (REVIEW)." In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. All-Russian Scientific Research Institute for Fundamental and Applied Parasitology of Animals and Plant – a branch of the Federal State Budget Scientific Institution “Federal Scientific Centre VIEV”, 2023. http://dx.doi.org/10.31016/978-5-6048555-6-0.2023.24.281-284.
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In the last few decades, the attention of researchers has been attracted by endogenous
FMRFamide-like neuropeptides found in a number of invertebrates, including
species of the Nematoda phylum. A foreign literature review was presented for
the functional significance of endogenous FMRFamide-like neuropeptides in
locomotor behaviour of root-knot phytonematodes, representatives of the genus
Meloidogyne Goldi, 1982, namely, Meloidogyne incognita, M. minor, M. hapla and
M. graminicola. In Russia, such studies are not carried out. The main characteristics
of phytoparasitic neuropeptides were obtained from the study of genes (flp-genes)
that encode these neuropeptides. M. incognita was found to have FMRFamidelike positive immunoreactivity in the central nervous system and 19 flp genes. The
Mi-flp-12 and Mi-flp-14 genes encode neuropeptides that stimulate locomotor
behaviour, while Mi-flp-32 encodes a neuropeptide that inhibits parasite locomotor
behaviour. Nematodes M. incognita and M. hapla were found to have G-proteincoupled receptors (GPCRs) encoded by the flp-32 gene, and their similarity
to receptor 1 (C26F1) of the free-living nematode Caenorhabditis elegans was
detected. Similar data were presented in the literature for M. graminicola. The
peptidergic signaling nervous system of root-knot phytonematodes is similar to the
system of nematodes in vertebrates and free-living nematodes, which indicates the
conservatism of the system in species of the entire Nematoda phylum.
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Lychagina, S. V., and V. V. Zakharova. "THE EFFECT OF MICRONUTRIENTS ON POTATO TUBERS COLONIZED BY NEMATODES DITYLENCHUS DESTRUCTOR IN ARTIFICIAL INFECTION." In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. VNIIP – FSC VIEV, 2024. http://dx.doi.org/10.31016/978-5-6050437-8-2.2024.25.246-250.
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Potatoes in our country are a vegetable crop of strategic importance. The merit of this vegetable is in its multifaceted use. But there are no potato varieties resistant to the potato tuber nematode yet. The potential is in biological and biochemical characteristics of varieties in addition to various mineral nutrition. The experiment studied the effect of various micronutrients on increasing the resistance of Gala potato plants to phytoparasitic nematodes Ditylenchus destructor during artificial infection of the apical tuber segments. Standard micronutrient chelated solutions (B10,1%K2 O44%; Ca10%; Cu15%; Fe11%; Mn13%; Zn15%) for experiments were prepared in concentrations as recommended by the manufacturer. Shallow scalpel incisions were made on the surface of each segment and a Ditylenchus destructor suspension was instilled into the incision. The segments wetted with the standard solutions were put in plastic lidded containers to preserve humidity. The variants were labeled and left for 20 days. The control variant was sprayed with clean water. At 20 days that were enough for nematode colonization in potato slices, the tuber segments and nematode populations therein were examined. The result of the Ditylenchus destructor development in the potato segments with the use of micronutrients showed that the least nematodes were observed in the variants treated with copper chelate (EDTA-Cu15%) and iron chelate (Fe11%). Slightly more of them were in the variant with potassium metaborate (B10,1%K2 O44%). The remaining experiment variants and the control variant had the largest number of nematodes and their larvae.
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Cerevkova, Andrea, Marek Renco, and Lenka Bobulska. "DIVERSITY OF SOIL NEMATODES IN THE TREATENED ECOSYSTEMS OF PONICKA CAVE." In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023v/6.2/s29.91.
Full textAbstract:
Ponicka Cave, situated in central Slovakia, is a natural wonder, known for its stunning stalagmites, stalactites, and underground lakes. This unique cave system has a hydrological connection to the Earth's surface, representing a very vulnerable habitat. Long-lasting intensive livestock grazing in the aquifer area of Ponicka cave and insufficiently insulated manure dump were the main reasons for the contamination of this cave. Soil nematodes are the most abundant multicellular organisms on Earth with respect to both species� richness and abundance. They are ubiquitous invertebrates in the soil that include a variety of feeding types, and they perform key functions in soil food webs. They are considered as one of the best soils bioindicators. Although the mesofauna of caves in Slovakia is relatively well described, information about soil nematodes are missing. In this study, we present the first data on the fauna of free-living and plant-parasitic nematode species from soil taken in the Karst region (karst spring, ponor, sink hole) and manure. Totally we identified 54 nematode species across 43 genera, 28 families, and 9 orders. The highest number of identified nematode species (44) was observed in Ponor, while 33 species were observed in both the karst springs and in a sinkhole and only 8 species were found in manure. Bacterivores were the dominant trophic group in all sites. Differences in nematode species composition in sites around Ponicka Cave, showing the differences in the environmental conditions nearby and site characteristic. This study emphasizes how important it is to know, understand and protect the soil biota that plays an important role in keeping the cave and the surrounding environment healthy.
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Kuchboev, A. E., O. O. Amirov, R. R. Karimova, K. F. Sobirov, and A. N. Ibragimov. "GASTROINTESTINAL NEMATODES IN MOUFFLONS AND DOMESTIC SHEEP IN PROTECTED AREAS OF UZBEKISTAN." In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. VNIIP – FSC VIEV, 2024. http://dx.doi.org/10.31016/978-5-6050437-8-2.2024.25.231-235.
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The article studied gastrointestinal nematodes in moufflons and domestic sheep in protected areas of Uzbekistan. Twenty-two nematode species were identified in the digestive tract of moufflons and domestic sheep including 21 species in domestic sheep, 7 in Severtsev’s sheep, 5 in Ustyurt mountain sheep, and 2 in Bokharan mountain sheep. Moreover, the family Trichostrongylidae includes 11 nematode species; Molineidae, 3 species; Trichinellidae, Strongylidae and Ancylostomatidae, 2 species each; and Onchocercidae, Gongylonematidae and Habronematidae, one species each. Nematodes of the species Setaria labiatopapillosa, Gongylonema pulchrum, Parabronema skrjabini are considered biohelminths, they develop with participation of beetles (Scarabiidae and Tenebrionidae fam.) and blood-sucking insects (Haematobia gen.); the rest species are geohelminths. It should be noted that the species Marshallagia marshalli and Teladosagia circumcincta were recorded in all animals studied; G. pulchrum and P. skrjabini in domestic sheep, Ustyurt mountain sheep and Severtsev’s sheep; Nematodirus abnormalis and N. helvetianis in domestic sheep and Severtsev’s sheep; and N. oiratianus in domestic sheep and Ustyurt mountain sheep.
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Sweets, Laura E. "Soybean Cyst Nematode." In Proceedings of the 28th Annual Integrated Crop Management Conference. Iowa State University, Digital Press, 1989. http://dx.doi.org/10.31274/icm-180809-297.
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Pimenov, I. A. "GASTROINTESTINAL NEMATODE FAUNA IN SMALL CATTLE IN THE EUROPEAN RUSSIA." In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. VNIIP – FSC VIEV, 2024. http://dx.doi.org/10.31016/978-5-6050437-8-2.2024.25.322-327.
Full textAbstract:
Gastrointestinal nematodes of small cattle are common in all Russian regions and cause diseases that can have a pronounced negative effect on the animal body. In this regard, obtaining data on the species composition of nematodes dwelling in the digestive tract of small cattle in different regions of the European part of the Russian Federation is of great scientific and practical interest since it will allow for the right strategy to control them. The study material was collected in slaughterhouses in the Moscow Region where animals were delivered from the Oryol, Astrakhan and Moscow Regions, the Republic of Dagestan and the Stavropol Territory from January to October 2023. For helminthological dissections, we used kits of gastrointestinal tracts of the sheep and goats collected immediately after slaughter. Nematodes of the species Trichostrongylus colubriformis and Teladorsagia circumcincta were found in all of the above Regions; nematodes of the species Haemonchus contortus were found in the Moscow and Astrakhan Regions as well as the Republic of Dagestan; and nematodes of the species Marshallagia marshalli were only found in the Astrakhan Region and the Republic of Dagestan. In addition to data on the species composition of gastrointestinal parasitic nematode fauna in small cattle, prevalence and infection intensity rates were determined in the above Regions of the European Russia.
Reports on the topic "Nematode"
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Samish, Michael, K. M. Kocan, and Itamar Glazer. Entomopathogenic Nematodes as Biological Control Agents of Ticks. United States Department of Agriculture, September 1992. http://dx.doi.org/10.32747/1992.7568104.bard.
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This research project was aimed to create a basis for the use of entomopathogenic nematodes (Steinernematidae an Heterorhabditidae) for biological control of ticks. The specific objectives were to determinate: 1) Nematode virulence to various. 2) Host-parasite interactions of nametodes and ticks. 3) Effect of environmental factors of tick habitats on nematode activity. 4) To test nematodes (anti tick activity) in defined field trials. Throughout the project 12 nematode strains from five species were tested in laboratory assays against all developmental stages of eight tick species. All tick species were found susceptible to nematode infection. The nematode strains the IS-5 and IS-12 of Heterorhabditis bacteriophora were found to be the most virulent. Engorged adults, particularly females, were the most susceptible stages. Despite the high susceptibility, ticks are not suitable hosts for nematode development and propagation. Entomopathogenic namatodes enter ticks and kill them by releasing the symbiotic bacteria from their foregut. Under favorable conditions, i.e. moist soil, moderate temperature (22-27oC) and sandy soil, nematode efficacy against B. annulatus engorged females was very high (>5% w/w) and high animal manure concentration in soil adversely effect nematode efficacy. In field trails, nematodes were effective when soil moisture was maintained at high levels. The results indicate that under favorable conditions the nematodes show promise as a biological control method for ticks. However, we still face several potential obstacles to the use of nematodes under less favorable conditions.
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McClure, Michael A., Yitzhak Spiegel, David M. Bird, R. Salomon, and R. H. C. Curtis. Functional Analysis of Root-Knot Nematode Surface Coat Proteins to Develop Rational Targets for Plantibodies. United States Department of Agriculture, October 2001. http://dx.doi.org/10.32747/2001.7575284.bard.
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The goal of this research was to provide a better understanding of the interface between root-knot nematodes, Meloidogyne spp., and their host in order to develop rational targets for plantibodies and other novel methods of nematode control directed against the nematode surface coat (SC). Specific objectives were: 1. To produce additional monoclonal SC antibodies for use in Objectives 2, 3, and 4 and as candidates for development of plantibodies. 2. To determine the production and distribution of SC proteins during the infection process. 3. To use biochemical and immunological methods to perturbate the root-knot nematode SC in order to identify SC components that will serve as targets for rationally designed plantibodies. 4. To develop SC-mutant nematodes as additional tools for defining the role of the SC during infection. The external cuticular layer of nematodes is the epicuticle. In many nematodes, it is covered by a fuzzy material termed "surface coat" (SC). Since the SC is the outermost layer, it may playa role in the interaction between the nematode and its surroundings during all life stages in soil and during pathogenesis. The SC is composed mainly of proteins, carbohydrates (which can be part of glycoproteins), and lipids. SC proteins and glycoproteins have been labeled and extracted from preparasitic second-stage juveniles and adult females of Meloidogyne and specific antibodies have been raised against surface antigens. Antibodies can be used to gain more information about surface function and to isolate genes encoding for surface antigens. Characterization of surface antigens and their roles in different life-stages may be an important step towards the development of alternative control. Nevertheless, the role of the plant- parasitic nematode's surface in plant-nematode interaction is still not understood. Carbohydrates or carbohydrate-recognition domains (CROs) on the nematode surface may interact with CROs or carbohydrate molecules, on root surfaces or exudates, or be active after the nematode has penetrated into the root. Surface antigens undoubtedly play an important role in interactions with microorganisms that adhere to the nematodes. Polyclonal (PC) and monoclonal (MC) antibodies raised against Meloidogyne javanica, M. incognita and other plant-parasitic nematodes, were used to characterize the surface coat and secreted-excreted products of M. javanica and M. incognita. Some of the MC and PC antibodies raised against M. incognita showed cross-reactivity with the surface coat of M. javanica. Further characterization, in planta, of the epitopes recognized by the antibodies, showed that they were present in the parasitic juvenile stages and that the surface coat is shed during root penetration by the nematode and its migration between root cells. At the molecular level, we have followed two lines of experimentation. The first has been to identify genes encoding surface coat (SC) molecules, and we have isolated and characterized a small family of mucin genes from M. incognita. Our second approach has been to study host genes that respond to the nematode, and in particular, to the SC. Our previous work has identified a large suite of genes expressed in Lycopersicon esculentum giant cells, including the partial cDNA clone DB#131, which encodes a serine/threonine protein kinase. Isolation and predicted translation of the mature cDNA revealed a frame shift mutation in the translated region of nematode sensitive plants. By using primers homologous to conserved region of DB#131 we have identified the orthologues from three (nematode-resistant) Lycopersicon peruvianum strains and found that these plants lacked the mutation.
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Spiegel, Yitzhak, Michael McClure, Itzhak Kahane, and B. M. Zuckerman. Characterization of the Phytophagous Nematode Surface Coat to Provide New Strategies for Biocontrol. United States Department of Agriculture, November 1995. http://dx.doi.org/10.32747/1995.7613015.bard.
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Chemical composition and biological role of the surface coat (SC) of the root-knot nematodes, Meloidogyne spp. are described. SC proteins of M. incognita race 3 infective juveniles (J2) were characterized by electrophoresis and western blotting of extracts from radioiodine and biotin-labelled nematodes. J2 labelled with radioiodine and biotin released 125I and biotin-labelled molecules into water after 20 hours incubation, indicating that SC proteins may be loosely attached to the nematode. Antiserum to the principal protein reacted with the surface of live J2 and with surface proteins previously separated by electrophoresis. Human red blood cells (HRBC) adhered to J2 of several tylenchid nematodes over the entire nematode body. HRBC adhered also to nylon fibers coated with SC extracted from M. javanica J2; binding was Ca++/Mg++ dependent, and decreased when the nylon fibers were coated with bovine serum albumin, or pre-incubated with fucose and mannose. These experiments support a working hypothesis that RBC adhesion involves carbohydrate moieties of HRBC and carbohydrate-recognition domain(s) (CRD) distributed on the nematode surface. To our knowledge, this is the first report of a surface CRD i the phylum Nematoda. Gold-conjugated lectins and neoglycoproteins combined with silver enhancement have been used for the detection of carbohydrates and CRD, respectively, on the SC of M. javanica J2. Biotin reagents were used to trace surface proteins, specifically, on live J2. The labile and transitory nature of the SC was demonstrated by the dynamics of HRBC adherence to detergent-treated J2, J2 at different ages or fresh-hatched J2 held at various temperatures. SC recovery was demonstrated also by a SDS-PAGE profile. Monoclonal antibodies developed to a cuticular protein of M. incognita J2 gave a slight, but significant reduction in attachment of Pasteuria penetrans spores. Spore attachment as affected by several enzymes was inconsistent: alcian blue, which specifically blocks sulfyl groups, had no afffect on spore attachment. Treatment with cationized ferritin alone or catonized ferritin following monoclonal antibody caused significant decreases in spore attachment. Those results suggest a role in attachment by negatively charged groups.
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Brown Horowitz, Sigal, Eric L. Davis, and Axel Elling. Dissecting interactions between root-knot nematode effectors and lipid signaling involved in plant defense. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598167.bard.
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Root-knot nematodes, Meloidogynespp., are extremely destructive pathogens with a cosmopolitan distribution and a host range that affects most crops. Safety and environmental concerns related to the toxicity of nematicides along with a lack of natural resistance sources threaten most crops in Israel and the U.S. This emphasizes the need to identify genes and signal mechanisms that could provide novel nematode control tactics and resistance breeding targets. The sedentary root-knot nematode (RKN) Meloidogynespp. secrete effectors in a spatial and temporal manner to interfere with and mimic multiple physiological and morphological mechanisms, leading to modifications and reprogramming of the host cells' functions, resulted in construction and maintenance of nematodes' feeding sites. For successful parasitism, many effectors act as immunomodulators, aimed to manipulate and suppress immune defense signaling triggered upon nematode invasion. Plant development and defense rely mainly on hormone regulation. Herein, a metabolomic profiling of oxylipins and hormones composition of tomato roots were performed using LC-MS/MS, indicating a fluctuation in oxylipins profile in a compatible interaction. Moreover, further attention was given to uncover the implication of WRKYs transcription factors in regulating nematode development. In addition, in order to identify genes that might interact with the lipidomic defense pathway induced by oxylipins, a RNAseq was performed by exposing M. javanicasecond-stage juveniles to tomato protoplast, 9-HOT and 13-KOD oxylipins. This transcriptome generated a total of 4682 differentially expressed genes (DEGs). Being interested in effectors, we seek for DEGs carrying a predicted secretion signal peptide. Among the DEGs including signal peptide, several had homology with known effectors in other nematode species, other unknown potentially secreted proteins may have a role as root-knot nematodes' effectors which might interact with lipid signaling. The molecular interaction of LOX proteins with the Cyst nematode effectors illustrate the nematode strategy in manipulating plant lipid signals. The function of several other effectors in manipulating plant defense signals, as well as lipids signals, weakening cell walls, attenuating feeding site function and development are still being studied in depth for several novel effectors. As direct outcome of this project, the accumulating findings will be utilized to improve our understanding of the mechanisms governing critical life-cycle phases of the parasitic M. incognita RKN, thereby facilitating design of effective controls based on perturbation of nematode behavior—without producing harmful side effects. The knowledge from this study will promote genome editing strategies aimed at developing nematode resistance in tomato and other nematode-susceptible crop species in Israel and the United States.
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Phillips, Donald A., Yitzhak Spiegel, and Howard Ferris. Optimizing nematode management by defining natural chemical bases of behavior. United States Department of Agriculture, November 2006. http://dx.doi.org/10.32747/2006.7587234.bard.
Full textAbstract:
This project was based on the hypothesis that nematodes interacting with plants as either parasites or beneficial saprophytes are attracted to their host by natural products. This concept was supported by numerous observations that parasitic nematodes are attracted to root exudates. Our overall goal was to identify nematode sensory compounds from root exudates and to use that information for reducing nematicide applications. We applied skills of the investigators to achieve three specific objectives: 1) Identify nematode behavioral cues (e.g., attractants or repellents) in root exudates; 2) Identify new natural nematicidal compounds; and 3) Combine a natural attractant and a nematicide into a nematode trap. Because saprophytic nematodes benefit plants by mineralizing organic matter, we sought compounds attractive primarily to parasitic nematodes. The project was constructed on several complementary foundations. First, data from Dr. Spiegel’s lab showed that under aseptic conditions Ditylenchus dipsaci, a parasite on onion, is attracted to certain fractions of onion root exudates. Second, PI Phillips had a sizeable collection of natural plant products he had identified from previous work on Rhizobium-legume interactions, which could be tested “off the shelf”. Third, Dr. Ferris had access to aseptic and natural populations of various saprophytic and parasitic nematodes. The project focused on five nematode species: D.dipsaci, Heterodera avenae, and Tylenchulussemipenetransat ARO, and Meloidogyne javanicand Caenorhabditis elegans at UCD. Ten pure plant compounds, mostly flavonoids, were tested on the various nematode species using six different assay systems. Results obtained with assorted test systems and by various scientists in the same test systems were essentially irreproducible. Many convincing, Many convincing, i.e. statistically significant, results in one system or with one investigator could not be repeated with other assays or different people. A recent report from others found that these compounds, plus another 30, were inactive as attractants in three additional parasitic nematode species (Wuyts et al. Nematology 8:89- 101, 2006). Assays designed to test the hypothesis that several compounds together are required to attract nematodes have thus far failed to find a reproducibly active combination. In contrast to results using pure plant compounds, complex unfractionated exudates from aseptic onion root reproducibly attracted D. dipsaci in both the ARO and UCD labs. Onion root exudate collection, separation into HPLC fractions, assays using D. dipsaci and MS-MS experiments proceeded collaboratively between ARO and UCD without any definitive identification of an active compound. The final active fraction contained two major molecules and traces of several other compounds. In the end, analytical studies were limited by the amount of onion root exudate and the complexity of the purification process. These tests showed that aseptic plant roots release attractant molecules, but whether nematodes influence that release, as insects trigger release of attractants from plants, is unknown. Related experiments showed that the saprophyte C. elegans stimulates its prey, Pseudomonas bacteria, to increase production of 2, 4-diacetylphloroglucinol (DAPG) a compound that promotes amino acid exudation by plant roots. It is thus possible that saprophytic nematodes are attracted primarily to their bacterial or fungal prey and secondarily to effects of those microorganisms on root exudation. These observations offer promising avenues for understanding root-zone interactions, but no direct routes to controlling nematodes in agriculture were evident. Extracts from two plant sources, Chrysanthemum coronarium and Sequoia sempervirens, showed nematicidal activity at ARO and UCD, respectively. Attempts to purify an active compound from S. sempervirens failed, but preliminary results from C. coronarium are judged to form a potential basis for further work at ARO. These results highlight the problems of studying complex movement patterns in sentient organisms like nematodes and the issues associated with natural product isolation from complex mixtures. Those two difficulties combined with complications now associated with obtaining US visas, slowed and ultimately limited progress on this project. As a result, US investigators expended only 65% of the $207,400 originally planned for this project. The Israeli side of the project advanced more directly toward its scientific goals and lists its expenditures in the customary financial report.
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Bissonnette, Kaitlyn, Travis Faske, and Albert Tenuta. Soybean Cyst Nematode. United States: Crop Protection Netework, April 2021. http://dx.doi.org/10.31274/cpn-20210423-0.
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Tylka, Gregory L., Mychele Batista Da Silva, R. Aaron Saeugling, and Stephanie Marlay. Effects of Nematode-Protectant Seed Treatments on Corn Yields and Nematode Population Densities. Ames: Iowa State University, Digital Repository, 2012. http://dx.doi.org/10.31274/farmprogressreports-180814-462.
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Gaugler, Randy, Itamar Glazer, Daniel Segal, and Sarwar Hashmi. Molecular Approach for Improving the Stability of Insecticidal Nematodes. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7580680.bard.
Full textAbstract:
Our overall goal is to improve insecticidal nematodes by genetically engineering strains capable of entering an enhanced state of dormancy that provides improved stability. Objectives: 1. Clone and sequence tps-l homologue from Steinernema carpocapsae. (Revised: A failure to isolate the tps gene group from Steinernema precipitated a redirection to identifying other genes involved in insecticidal nematode desiccation process.) 2. Incorporate cloned tps-l gene into S. carpocapsae to obtain overexpression, thereby, enhancing desiccation tolerance. (Revised: Other stress genes in addition to tps-l genes were cloned and efforts at expression in S. carpocapsae were conducted) 3. Characterize the transgenic strains. No other biological control agent offers more impressive attributes than insecticidal nematodes. However, their potential is limited by the bane of nearly all biological control agents: poor stability. This leads to inadequate shelf-life and ultimately reduced field efficacy. Nematode storage is based on desiccation, yet insecticidal species are only capable of partial desiccation termed quiescent anhydrobiosis. Overwhelming evidence has shown that when the disaccharide compound trehalose is elevated in anhydrobiotic organisms such as yeast, plants, and nematodes it enables these organisms the ability to survive environmental stresses i.e., desiccation. Armed with this information our goal was to improve insecticidal nematodes stability by engineering trehalose overexpression.
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Lawson, Vincent, Gregory L. Tylka, Christopher C. Marett, and Gregory D. Gebhart. Soybean Cyst Nematode Resistant Soybean Trial. Ames: Iowa State University, Digital Repository, 2007. http://dx.doi.org/10.31274/farmprogressreports-180814-938.
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Davis, Eric L., Yuji Oka, Amit Gal-On, Todd Wehner, and Aaron Zelcer. Broad-spectrum Resistance to Root-Knot Nematodes in Transgenic Cucurbits. United States Department of Agriculture, June 2013. http://dx.doi.org/10.32747/2013.7593389.bard.
Full textAbstract:
Root-knot nematodes (RKN), Meloidogyne spp., are extremely destructive pathogens of cucurbit crops grown in the United States and Israel. The safety and environmental concerns of toxic nematicides, and limited sources of natural cucurbit resistance to the four major species of Meloidogyne that threaten these crops in Israel and the U.S., have emphasized the use of biotechnology to develop cucurbits with novel RKN resistance. The U.S. scientists have identified over 40 unique RKN parasitism genes that encode nematode secretions involved in successful plant root infection by RKN, and they have demonstrated that expression of a double-stranded RNA (dsRNA) complementary to a RKN parasitism gene (called 16DIO) in Arabidopsis thaliana induced RNA interference (RNAi)-mediated silencing of the RKN16DlO gene and produced transgenic plants with strong resistance to all four major RKN species. The expression 8D05 parasitism gene was found to coincide with the timing of upregulation of NtCel7 promoter (identified to be upregulated in giantcells by US scientists). NtCel7 promoter was used to express the genes at the right time (early stages of infection) and in the right place (giant-cells) in transgenic plants. US partners produced NtCel7 (nematode-induced promoter)-driven 16DlO-RNAi and 8DOS-RNAi constructs, pHANNIBAL 4D03-RNAi construct and modified 16DlO-RNAi construct (for increased RNAi expression and efficacy) for cucurbit transformation in Israel. In Arabidopsis, some 16DlO-RNAi plant lines show greater levels of resistance to M. incognita than others, and within these lines resistance of greater than 90% reduction in infection is observed among almost all replicates in US. The level of observed nematode resistance is likely to be directly correlated with the level of RNAi expression in individual plants. In Israel, all the RKN parasitism genes-RNAi constructs were successfully transformed into cucumber and melon. The transgenic lines were evaluated for expression of the transgene siRNA in leaves and roots. Those displaying transgene siRNA accumulation were passed on for nematode resistance analysis. Rl seedlings from different lines were subjected to evaluation for resistance to M. javanica. None of the lines was resistant to the nematode in contrast with US partner's results in Arabidopsis. This could be for the following reasons: a) The level of transgene siRNA was insufficient in cucumber and tomato to cause resislance. b) 111e nemalode species on cucwnber IIlay be different ur act in a different manner. c) The assay was performed in soil with a high level of nematode inoculation, and not in petri dish, which may not permit the observation of a low level of resistance.