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Sample records for suppress plant-parasitic nematodes

  1. The novel GrCEP12 peptide from the plant-parasitic nematode Globodera rostochiensis suppresses flg22-mediated PTI.

    Science.gov (United States)

    Chen, Shiyan; Chronis, Demosthenis; Wang, Xiaohong

    2013-09-01

    The potato cyst nematode Globodera rostochiensis is a biotrophic pathogen that secretes effector proteins into host root cells to promote successful plant parasitism. In addition to the role in generating within root tissue the feeding cells essential for nematode development, (1) nematode secreted effectors are becoming recognized as suppressors of plant immunity. (2)(-) (4) Recently we reported that the effector ubiquitin carboxyl extension protein (GrUBCEP12) from G. rostochiensis is processed into free ubiquitin and a 12-amino acid GrCEP12 peptide in planta. Transgenic potato lines overexpressing the derived GrCEP12 peptide showed increased susceptibility to G. rostochiensis and to an unrelated bacterial pathogen Streptomyces scabies, suggesting that GrCEP12 has a role in suppressing host basal defense or possibly pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) during the parasitic interaction. (3) To determine if GrCEP12 functions as a PTI suppressor we evaluated whether GrCEP12 suppresses flg22-induced PTI responses in Nicotiana benthamiana. Interestingly, we found that transient expression of GrCEP12 in N. benthamiana leaves suppressed reactive oxygen species (ROS) production and the induction of two PTI marker genes triggered by the bacterial PAMP flg22, providing direct evidence that GrCEP12 indeed has an activity in PTI suppression.

  2. Plant-parasitic nematodes in Hawaiian agriculture

    Science.gov (United States)

    Hawaii’s diverse and mild climate allows for the cultivation of many crops. The introduction of each crop plant brought along its associated nematode pests. These plant-parasitic nematodes became established and are now endemic to the islands. Plantation agriculture determined the major nematode ...

  3. Genome Evolution of Plant-Parasitic Nematodes.

    Science.gov (United States)

    Kikuchi, Taisei; Eves-van den Akker, Sebastian; Jones, John T

    2017-08-04

    Plant parasitism has evolved independently on at least four separate occasions in the phylum Nematoda. The application of next-generation sequencing (NGS) to plant-parasitic nematodes has allowed a wide range of genome- or transcriptome-level comparisons, and these have identified genome adaptations that enable parasitism of plants. Current genome data suggest that horizontal gene transfer, gene family expansions, evolution of new genes that mediate interactions with the host, and parasitism-specific gene regulation are important adaptations that allow nematodes to parasitize plants. Sequencing of a larger number of nematode genomes, including plant parasites that show different modes of parasitism or that have evolved in currently unsampled clades, and using free-living taxa as comparators would allow more detailed analysis and a better understanding of the organization of key genes within the genomes. This would facilitate a more complete understanding of the way in which parasitism has shaped the genomes of plant-parasitic nematodes.

  4. Biochar-enhanced composts reduce the potential leaching of nutrients and heavy metals and suppress plant-parasitic nematodes in excessively fertilized cucumber soils.

    Science.gov (United States)

    Cao, Yune; Gao, Yanming; Qi, Yanbin; Li, Jianshe

    2018-03-01

    Excessive fertilization is a common agricultural practice that has largely reduced soil nutrient retention capacity and led to nutrient leaching in China. To reduce nutrient leaching, in this study, we evaluated the application of biochar, compost, and biochar-compost on soil properties, leaching water quality, and cucumber plant growth in soils with different nutrient levels. In general, the concentrations of nutrients and heavy metals in leaching water were higher under high-nutrient conditions than under low-nutrient conditions. Both biochar and compost efficiently enhanced soil cation exchange capacity (CEC), water holding capacity (WHC), and microbial biomass carbon (MBC), nitrogen (MBN), and phosphorus (MBP), reduced the potential leaching of nutrients and heavy metals, and improved plant growth. The efficiency of biochar and compost in soil CEC, WHC, MBC, MBN, and MBP and plant growth was enhanced when applied jointly. In addition, biochar and biochar-enhanced compost efficiently suppressed plant-parasitic nematode infestation in a soil with high levels of both N and P. Our results suggest that biochar-enhanced compost can reduce the potential environmental risks in excessively fertilized vegetable soils.

  5. RNA Interference: A Novel Source of Resistance to Combat Plant Parasitic Nematodes

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    Sagar Banerjee

    2017-05-01

    Full Text Available Plant parasitic nematodes cause severe damage and yield loss in major crops all over the world. Available control strategies include use of insecticides/nematicides but these have proved detrimental to the environment, while other strategies like crop rotation and resistant cultivars have serious limitations. This scenario provides an opportunity for the utilization of technological advances like RNA interference (RNAi to engineer resistance against these devastating parasites. First demonstrated in the model free living nematode, Caenorhabtidis elegans; the phenomenon of RNAi has been successfully used to suppress essential genes of plant parasitic nematodes involved in parasitism, nematode development and mRNA metabolism. Synthetic neurotransmitants mixed with dsRNA solutions are used for in vitro RNAi in plant parasitic nematodes with significant success. However, host delivered in planta RNAi has proved to be a pioneering phenomenon to deliver dsRNAs to feeding nematodes and silence the target genes to achieve resistance. Highly enriched genomic databases are exploited to limit off target effects and ensure sequence specific silencing. Technological advances like gene stacking and use of nematode inducible and tissue specific promoters can further enhance the utility of RNAi based transgenics against plant parasitic nematodes.

  6. Top 10 plant-parasitic nematodes in molecular plant pathology

    NARCIS (Netherlands)

    Jones, J.T.; Haegeman, A.; Danchin, E.G.J.; Gaur, H.S.; Helder, J.; Jones, M.G.K.; Kikuchi, T.; Manzanilla-López, R.; Palomares-Rius, J.E.; Wesemael, W.M.L.; Perry, R.N.

    2013-01-01

    The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a ‘top 10’ list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region

  7. RNA interference in plant parasitic nematodes

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... grower preference or by government restrictions to limit the environmental ... risks associated with chemical control and (c) the pro- vision of ... certain model organisms. The first ... reproductive system (Lilley et al., 2005b), sperm (Urwin .... interference of dual oxidase in the plant nematode Meloidogyne.

  8. Rhizosphere Microbiomes Modulated by Pre-crops Assisted Plants in Defense Against Plant-Parasitic Nematodes

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    Ahmed Elhady

    2018-06-01

    Full Text Available Plant-parasitic nematodes cause considerable damage to crop plants. The rhizosphere microbiome can affect invasion and reproductive success of plant-parasitic nematodes, thus affecting plant damage. In this study, we investigated how the transplanted rhizosphere microbiome from different crops affect plant-parasitic nematodes on soybean or tomato, and whether the plant’s own microbiome from the rhizosphere protects it better than the microbiome from fallow soil. Soybean plants growing in sterilized substrate were inoculated with the microbiome extracted from the rhizosphere of soybean, maize, or tomato. Controls were inoculated with extracts from bulk soil, or not inoculated. After the microbiome was established, the root lesion nematode Pratylenchus penetrans was added. Root invasion of P. penetrans was significantly reduced on soybean plants inoculated with the microbiome from maize or soybean compared to tomato or bulk soil, or the uninoculated control. In the analogous experiment with tomato plants inoculated with either P. penetrans or the root knot nematode Meloidogyne incognita, the rhizosphere microbiomes of maize and tomato reduced root invasion by P. penetrans and M. incognita compared to microbiomes from soybean or bulk soil. Reproduction of M. incognita on tomato followed the same trend, and it was best suppressed by the tomato rhizosphere microbiome. In split-root experiments with soybean and tomato plants, a systemic effect of the inoculated rhizosphere microbiomes on root invasion of P. penetrans was shown. Furthermore, some transplanted microbiomes slightly enhanced plant growth compared to uninoculated plants. The microbiomes from maize rhizosphere and bulk soil increased the fresh weights of roots and shoots of soybean plants, and microbiomes from soybean rhizosphere and bulk soil increased the fresh weights of roots and shoots of tomato plants. Nematode invasion did not affect plant growth in these short-term experiments. In

  9. Top 10 plant-parasitic nematodes in molecular plant pathology.

    Science.gov (United States)

    Jones, John T; Haegeman, Annelies; Danchin, Etienne G J; Gaur, Hari S; Helder, Johannes; Jones, Michael G K; Kikuchi, Taisei; Manzanilla-López, Rosa; Palomares-Rius, Juan E; Wesemael, Wim M L; Perry, Roland N

    2013-12-01

    The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a 'top 10' list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region of the world in which a researcher is based. However, care was taken to include researchers from as many parts of the world as possible when carrying out the survey. The top 10 list emerging from the survey is composed of: (1) root-knot nematodes (Meloidogyne spp.); (2) cyst nematodes (Heterodera and Globodera spp.); (3) root lesion nematodes (Pratylenchus spp.); (4) the burrowing nematode Radopholus similis; (5) Ditylenchus dipsaci; (6) the pine wilt nematode Bursaphelenchus xylophilus; (7) the reniform nematode Rotylenchulus reniformis; (8) Xiphinema index (the only virus vector nematode to make the list); (9) Nacobbus aberrans; and (10) Aphelenchoides besseyi. The biology of each nematode (or nematode group) is reviewed briefly. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  10. [Screening endophytic bacteria against plant-parasitic nematodes].

    Science.gov (United States)

    Peng, Shuang; Yan, Shuzhen; Chen, Shuanglin

    2011-03-01

    Plant-parasite nematode is one of the most important pathogens in plant. Our objective is to screen endophytic bacteria against plant-parasitic nematodes from plant. Endophytic bacteria were isolated and screened by testing their metabolite against Bursaphelenchus xylophilus in vitro. Those strains inhibiting B. xylophilus were selected to culture in liquid medium and fermentation conditions were optimized by orthogonal test. The stability of the antinematode substances was evaluated by various. In addition, four strains were identified by 16SrDNA sequence analysis. In total 13 strains of endophytic bacteria secreting antinematode metabolite were isolated from 6 species of plant. The supernatant of the fermentation broth of these endophytic bacteria gave 100% mortality of nematodes after treated as the follows: 1 ml each was mixed with 0.2 ml of the suspension of nematodes (2000 nematodes/ml) then incubated at 250C for 24 h, some of which could led to leakage or dissolution of nematodes. Among them, four strains, BCM2, SZ5, CCM7 and DP1, showed stronger activity than others. The supernatants diluted three times also gave not less than 95% mortality after 24 h treatment, and those from DP1 and SZ5 even gave 100% mortality. The fermentation conditions of the four strains were optimized and the antinematode activity grew up four times after optimization. The antinematode substances of these strains were found stable when treated with protease or heating or stored at 4 degrees C after 100 days, while instable when treated with acid or alkali. DP1 and CCM7 were identified to be Bacillus subtilis, while SZ5 and BCM2 to be Bacillus cereus. Endophytic bacteria secreting antinematode metabolite were found in economic crops. The metabolite of some strains showed strong and stable antinematode activity. Our results indicate the real potential of biocontrol by endophytic bacteria.

  11. Biochemical and Molecular Characterization of Plant-Parasitic Nematodes

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    I.M. de O. Abrantes

    2004-08-01

    Full Text Available Nematologists need correct species identification to carry out research, teaching, extension and other activities. Therefore, nematode taxonomy must be pursued diligently at all levels. The identification of plant-parasitic nematodes is not always easy and that of some species is especially difficult. Most of the information that nematologists use when characterizing and identifying specimens is based on morphological and morphometrical characters. Although these characters are of primary importance, in the last three decades they have been supplemented by biochemical/ molecular characters. Biochemical approaches include the separation of proteins (general proteins and isozymes by one-dimensional gel electrophoresis, isoelectric focusing, two-dimensional gel electrophoresis, and sodium dodecyl sulphate-capillary gel electrophoresis. Serology has also been found effective in the identification and quantification of nematodes, monoclonal antibodies being a more useful immunological tool than polyclonal antibodies. Identification based on the direct examination of DNA is potentially a more powerful method to characterize inter- and intra-specific variability. The development of techniques such as the polymerase chain reaction, restriction fragment length polymorphism, randomly amplified polymorphic DNA, and amplified fragment length polymorphism has increased the accuracy and speed of nematode characterization/identification. Progress continues to be made and more and more nematologists are using molecular techniques for diagnostic purposes and to assess genetic variation.

  12. Exploring the host parasitism of the migratory plant-parasitic nematode Ditylenchus destuctor by expressed sequence tags analysis.

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    Huan Peng

    Full Text Available The potato rot nematode, Ditylenchus destructor, is a very destructive nematode pest on many agriculturally important crops worldwide, but the molecular characterization of its parasitism of plant has been limited. The effectors involved in nematode parasitism of plant for several sedentary endo-parasitic nematodes such as Heterodera glycines, Globodera rostochiensis and Meloidogyne incognita have been identified and extensively studied over the past two decades. Ditylenchus destructor, as a migratory plant parasitic nematode, has different feeding behavior, life cycle and host response. Comparing the transcriptome and parasitome among different types of plant-parasitic nematodes is the way to understand more fully the parasitic mechanism of plant nematodes. We undertook the approach of sequencing expressed sequence tags (ESTs derived from a mixed stage cDNA library of D. destructor. This is the first study of D. destructor ESTs. A total of 9800 ESTs were grouped into 5008 clusters including 3606 singletons and 1402 multi-member contigs, representing a catalog of D. destructor genes. Implementing a bioinformatics' workflow, we found 1391 clusters have no match in the available gene database; 31 clusters only have similarities to genes identified from D. africanus, the most closely related species to D. destructor; 1991 clusters were annotated using Gene Ontology (GO; 1550 clusters were assigned enzyme commission (EC numbers; and 1211 clusters were mapped to 181 KEGG biochemical pathways. 22 ESTs had similarities to reported nematode effectors. Interestedly, most of the effectors identified in this study are involved in host cell wall degradation or modification, such as 1,4-beta-glucanse, 1,3-beta-glucanse, pectate lyase, chitinases and expansin, or host defense suppression such as calreticulin, annexin and venom allergen-like protein. This result implies that the migratory plant-parasitic nematode D. destructor secrets similar effectors to

  13. Molecular mechanisms of nematode-nematophagous microbe interactions: basis for biological control of plant-parasitic nematodes.

    Science.gov (United States)

    Li, Juan; Zou, Chenggang; Xu, Jianping; Ji, Xinglai; Niu, Xuemei; Yang, Jinkui; Huang, Xiaowei; Zhang, Ke-Qin

    2015-01-01

    Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.

  14. AMF-induced biocontrol against plant parasitic nematodes in Musa sp.: a systemic effect.

    Science.gov (United States)

    Elsen, A; Gervacio, D; Swennen, R; De Waele, D

    2008-07-01

    Although mycorrhizal colonization provides a bioprotectional effect against a broad range of soil-borne pathogens, including plant parasitic nematodes, the commercial use of arbuscular mycorrhizal fungi (AMF) as biocontrol agents is still in its infancy. One of the main reasons is the poor understanding of the modes of action. Most AMF mode of action studies focused on AMF-bacterial/fungal pathogens. Only few studies so far examined AMF-plant parasitic nematode interactions. Therefore, the aim of the study was to determine whether the AMF Glomus intraradices was able to incite systemic resistance in banana plants towards Radopholus similis and Pratylenchus coffeae, two plant parasitic nematodes using a split-root compartmental set-up. The AMF reduced both nematode species by more than 50%, even when the AMF and the plant parasitic nematodes were spatially separated. The results obtained demonstrate for the first time that AMF have the ability to induce systemic resistance against plant parasitic nematodes in a root system.

  15. Genome sequence of the metazoan plant-parasitic nematode Meloidogyne incognita

    NARCIS (Netherlands)

    Abad, P.; Gouzy, J.; Aury, J.M.; Tytgat, T.O.G.; Smant, G.

    2008-01-01

    Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the

  16. The plant-parasitic nematode collections of RRIP: The realization of an ISTC project

    Science.gov (United States)

    Plant-parasitic nematodes are important pests of agricultural and wild plants throughout Russia and the world. The best strategy for management of nematode damage is an integrated approach to the problem: i.e., the use of agrotechnological approaches (crop rotation, soil amendments, etc.), reasonabl...

  17. Diversity and incidence of plant-parasitic nematodes in Belgian turf grass

    NARCIS (Netherlands)

    Vandenbossche, B.; Viaene, N.; Sutter, de N.; Maes, M.; Karssen, G.; Bert, W.

    2011-01-01

    Eleven golf courses and eight football pitches, located in Belgium, were surveyed for plant-parasitic nematodes. This revealed a remarkably high diversity: 52 different species/taxa were identified morphologically, belonging to 23 genera and nine families. Among the most prevalent nematodes on both

  18. The Ditylenchus destructor genome provides new insights into the evolution of plant parasitic nematodes.

    Science.gov (United States)

    Zheng, Jinshui; Peng, Donghai; Chen, Ling; Liu, Hualin; Chen, Feng; Xu, Mengci; Ju, Shouyong; Ruan, Lifang; Sun, Ming

    2016-07-27

    Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans, the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plant-parasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants. © 2016 The Author(s).

  19. A ubiquitin carboxyl extension protein secreted from a plant-parasitic nematode Globodera rostochiensis is cleaved in planta to promote plant parasitism.

    Science.gov (United States)

    Chronis, Demosthenis; Chen, Shiyan; Lu, Shunwen; Hewezi, Tarek; Carpenter, Sara C D; Loria, Rosemary; Baum, Thomas J; Wang, Xiaohong

    2013-04-01

    Nematode effector proteins originating from esophageal gland cells play central roles in suppressing plant defenses and in formation of the plant feeding cells that are required for growth and development of cyst nematodes. A gene (GrUBCEP12) encoding a unique ubiquitin carboxyl extension protein (UBCEP) that consists of a signal peptide for secretion, a mono-ubiquitin domain, and a 12 amino acid carboxyl extension protein (CEP12) domain was cloned from the potato cyst nematode Globodera rostochiensis. This GrUBCEP12 gene was expressed exclusively within the nematode's dorsal esophageal gland cell, and was up-regulated in the parasitic second-stage juvenile, correlating with the time when feeding cell formation is initiated. We showed that specific GrUBCEP12 knockdown via RNA interference reduced nematode parasitic success, and that over-expression of the secreted Gr(Δ) (SP) UBCEP12 protein in potato resulted in increased nematode susceptibility, providing direct evidence that this secreted effector is involved in plant parasitism. Using transient expression assays in Nicotiana benthamiana, we found that Gr(Δ) (SP) UBCEP12 is processed into free ubiquitin and a CEP12 peptide (GrCEP12) in planta, and that GrCEP12 suppresses resistance gene-mediated cell death. A target search showed that expression of RPN2a, a gene encoding a subunit of the 26S proteasome, was dramatically suppressed in Gr(Δ) (SP) UBCEP12 but not GrCEP12 over-expression plants when compared with control plants. Together, these results suggest that, when delivered into host plant cells, Gr(Δ) (SP) UBCEP12 becomes two functional units, one acting to suppress plant immunity and the other potentially affecting the host 26S proteasome, to promote feeding cell formation. © 2013 The Authors The Plant Journal © 2013 Blackwell Publishing Ltd.

  20. Plant actin cytoskeleton re-modeling by plant parasitic nematodes.

    Science.gov (United States)

    Engler, Janice de Almeida; Rodiuc, Natalia; Smertenko, Andrei; Abad, Pierre

    2010-03-01

    The cytoskeleton is an important component of the plant's defense mechanism against the attack of pathogenic organisms. Plants however, are defenseless against parasitic root-knot and cyst nematodes and respond to the invasion by the development of a special feeding site that supplies the parasite with nutrients required for the completion of its life cycle. Recent studies of nematode invasion under treatment with cytoskeletal drugs and in mutant plants where normal functions of the cytoskeleton have been affected, demonstrate the importance of the cytoskeleton in the establishment of a feeding site and successful nematode reproduction. It appears that in the case of microfilaments, nematodes hijack the intracellular machinery that regulates actin dynamics and modulate the organization and properties of the actin filament network. Intervening with this process reduces the nematode infection efficiency and inhibits its life cycle. This discovery uncovers a new pathway that can be exploited for the protection of plants against nematodes.

  1. Functional characterization of CLE peptides from a plant-parasitic nematode Globodera rostochiensis

    Science.gov (United States)

    Plant CLAVATA3/ESR (CLE) proteins are a large family of secreted peptide ligands that play important roles in plant growth and development. Recent evidence suggests that plant-parasitic cyst nematodes secrete ligand mimics of plant CLE peptides to modify selected host root cells into multinucleate f...

  2. On the modulation of innate immunity by plant-parasitic cyst nematodes

    NARCIS (Netherlands)

    Postma, W.J.

    2013-01-01

    Plant-parasitic cyst nematodes are major agricultural pests worldwide. These obligate endoparasites invade the roots of host plants where they transform cells near the vascular cylinder into a permanent feeding site. Plants possess a multilayered innate immune system consisting of different

  3. Plant-parasitic nematodes associated with olive trees in Al-Jouf region, north Saudi Arabia

    Science.gov (United States)

    A preliminary survey of plant-parasitic nematodes associated with olive was performed in Al-Jouf region, north Saudi Arabia. Olive is a newly introduced crop in this region, and is cultivated in the agricultural enterprises of some of the biggest Saudi agricultural companies. Seedlings are mostly im...

  4. Novel RNA viruses within plant parasitic cyst nematodes.

    Science.gov (United States)

    Ruark, Casey L; Gardner, Michael; Mitchum, Melissa G; Davis, Eric L; Sit, Tim L

    2018-01-01

    The study of invertebrate-and particularly nematode-viruses is emerging with the advancement of transcriptome sequencing. Five single-stranded RNA viruses have now been confirmed within the economically important soybean cyst nematode (SCN; Heterodera glycines). From previous research, we know these viruses to be widespread in greenhouse and field populations of SCN. Several of the SCN viruses were also confirmed within clover (H. trifolii) and beet (H. schachtii) cyst nematodes. In the presented study, we sequenced the transcriptomes of several inbred SCN populations and identified two previously undiscovered viral-like genomes. Both of these proposed viruses are negative-sense RNA viruses and have been named SCN nyami-like virus (NLV) and SCN bunya-like virus (BLV). Finally, we analyzed publicly available transcriptome data of two potato cyst nematode (PCN) species, Globodera pallida and G. rostochiensis. From these data, a third potential virus was discovered and called PCN picorna-like virus (PLV). PCN PLV is a positive-sense RNA virus, and to the best of our knowledge, is the first virus described within PCN. The presence of these novel viruses was confirmed via qRT-PCR, endpoint PCR, and Sanger sequencing with the exception of PCN PLV due to quarantine restrictions on the nematode host. While much work needs to be done to understand the biological and evolutionary significance of these viruses, they offer insight into nematode ecology and the possibility of novel nematode management strategies.

  5. Rooting out Defense Mechanisms in Wheat against Plant Parasitic Nematodes

    Science.gov (United States)

    Root-lesion nematodes (Pratylenchus spp.) are soil borne pathogens of many important agricultural crops including wheat. Pratylenchus invade root cells and feed using a stylet, resulting in cell death. Common signs of Pratylenchus damage are root lesions, girdling, and lack of lateral branching. ...

  6. On the track of transfer cell formation by specialized plant-parasitic nematodes.

    Science.gov (United States)

    Rodiuc, Natalia; Vieira, Paulo; Banora, Mohamed Youssef; de Almeida Engler, Janice

    2014-01-01

    Transfer cells are ubiquitous plant cells that play an important role in plant development as well as in responses to biotic and abiotic stresses. They are highly specialized and differentiated cells playing a central role in the acquisition, distribution and exchange of nutrients. Their unique structural traits are characterized by augmented ingrowths of invaginated secondary wall material, unsheathed by an amplified area of plasma membrane enriched in a suite of solute transporters. Similar morphological features can be perceived in vascular root feeding cells induced by sedentary plant-parasitic nematodes, such as root-knot and cyst nematodes, in a wide range of plant hosts. Despite their close phylogenetic relationship, these obligatory biotrophic plant pathogens engage different approaches when reprogramming root cells into giant cells or syncytia, respectively. Both nematode feeding-cells types will serve as the main source of nutrients until the end of the nematode life cycle. In both cases, these nematodes are able to remarkably maneuver and reprogram plant host cells. In this review we will discuss the structure, function and formation of these specialized multinucleate cells that act as nutrient transfer cells accumulating and synthesizing components needed for survival and successful offspring of plant-parasitic nematodes. Plant cells with transfer-like functions are also a renowned subject of interest involving still poorly understood molecular and cellular transport processes.

  7. On the track of transfer cells formation by specialized plant-parasitic nematodes

    Directory of Open Access Journals (Sweden)

    Natalia eRodiuc

    2014-05-01

    Full Text Available Transfer cells are ubiquitous plant cells that play an important role in plant development as well as in responses to biotic and abiotic stresses. They are highly specialized and differentiated cells playing a central role in the acquisition, distribution and exchange of nutrients. Their unique structural traits are characterized by augmented ingrowths of invaginated secondary wall material, unsheathed by an amplified area of plasma membrane enriched in a suite of solute transporters. Similar morphological features can be perceived in vascular root feeding cells induced by sedentary plant-parasitic nematodes, such as root-knot and cyst nematodes, in a wide range of plant hosts. Despite their close phylogenetic relationship, these obligatory biotrophic plant pathogens engage different approaches when reprogramming root cells into giant cells or syncytia, respectively. Both nematode feeding-cells types will serve as the main source of nutrients until the end of the nematode life cycle. In both cases, these nematodes are able to remarkably maneuver and reprogram plant host cells. In this review we will discuss the structural, functional and morphogenetic characteristics function and formation of these specialized multinucleate cells that act as nutrient transfer cells to accumulate and synthesize components needed for survival and successful offspring of plant-parasitic nematodes. Plant cells with transfer-like functions are also a renowned subject of interest involving still poorly understood molecular and cellular transport processes.

  8. PLANT-PARASITIC NEMATODES ON STONE FRUITS AND CITRUS IN LEBANON

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    Said K. Ibrahim

    2016-06-01

    Full Text Available Ibrahim Said K., Ibrahim Azar, Christian Naser, Badran Akikki and Ludmilla Ibrahim. 2016. Plant-parasitic nematodes on stone fruits and citrus in Lebanon. Lebanese Science Journal, 17(1: 9-24. This study aimed to determine the occurrence, distribution of plant parasitic nematodes on stone fruits in Lebanon and to determine the effect of plant extracts on the mortality of several nematode species. A total of 308 soil samples were collected from five different crops. Almost all surveyed areas showed infection with nematodes. The soil infestation rate with nematodes in collected soil samples from all 10 surveyed crops ranged from 66.6 to 100%. Eighteen out of 308 soil samples were free of nematodes (5.8%. All the collected soil samples from nectarine and plum orchards were infested with nematodes (100%, followed by citrus (97.6%, apple (88.7%, pear and quince (85.7%, and cherry (81.4%. The lowest infection (66.6% was detected on almond and apricot. The level of infestation varied from one area to another and ranged between 0.1 and 28 nematodes per 1 g of soil, with the highest number obtained on cherry. Several genera were identified based on morphological characters including: root-knot nematodes (Meloidogyne spp., Tylenchulus, Xiphinema, Rotylenchus, Pratylenchus, and Longidorus. Tylenchulus and Radopholus spp. were the most common on citrus trees, whereas Pratylechus and Meloidogyne spp. were detected almost in all the samples collected from all the crops. Six chopped aromatic plants were tested in pot experiments to control nematodes population densities. The results revealed that carbofuran (nematicide was the most effective (88.48% in comparison to the plant materials. Allium sativum gave the highest control (76.52% followed by Tageta patula (72.0%, Cucurbita maxima (71.84% and Inula viscosa (63.96%. Origanum syriacum (55.04% and Thymus (53.72% were less effective in comparison to the rest of tested plant materials.

  9. The genome and life-stage specific transcriptomes of Globodera pallida elucidate key aspects of plant parasitism by a cyst nematode

    KAUST Repository

    Cotton, James A; Lilley, Catherine J; Jones, Laura M; Kikuchi, Taisei; Reid, Adam J; Thorpe, Peter; Tsai, Isheng J; Beasley, Helen; Blok, Vivian; Cock, Peter J A; den Akker, Sebastian Eves-van; Holroyd, Nancy; Hunt, Martin; Mantelin, Sophie; Naghra, Hardeep; Pain, Arnab; Palomares-Rius, Juan E; Zarowiecki, Magdalena; Berriman, Matthew; Jones, John T; Urwin, Peter E

    2014-01-01

    -knot nematodes are the two most important plant parasitic nematode groups and together represent a global threat to food security. Results: We present the complete genome sequence of G. pallida, together with transcriptomic data from most of the nematode life

  10. Toxicity of 2,4-diacetylphloroglucinol (DAPG) to plant-parasitic and bacterial-feeding nematodes.

    Science.gov (United States)

    Meyer, Susan L F; Halbrendt, John M; Carta, Lynn K; Skantar, Andrea M; Liu, Ting; Abdelnabby, Hazem M E; Vinyard, Bryan T

    2009-12-01

    The antibiotic 2,4-diacetylphloroglucinol (DAPG) is produced by some isolates of the beneficial bacterium Pseudomonas fluorescens. DAPG is toxic to many organisms, and crop yield increases have been reported after application of DAPG-producing P. fluorescens. This study was conducted to determine whether DAPG is toxic to selected nematodes. The plant-parasitic nematodes Heterodera glycines, Meloidogyne incognita, Pratylenchus scribneri and Xiphinema americanum, and the bacterial-feeding nematodes Caenorhabditis elegans, Pristionchus pacificus, and Rhabditis rainai, were immersed in concentrations ranging from 0 to 100 μg/ml DAPG. Egg hatch and viability of juveniles and adults were determined. DAPG was toxic to X. americanum adults, with an LD₅₀ of 8.3 μg/ml DAPG. DAPG decreased M. incognita egg hatch, but stimulated C. elegans hatch during the first hours of incubation. Viability of M. incognita J2 and of C. elegans J1 and adults was not affected. There were no observed effects on the other nematodes. The study indicated that DAPG is not toxic to all nematodes, and did not affect the tested species of beneficial bacterial-feeding nematodes. Augmentation of DAPG-producing P. fluorescens populations for nematode biocontrol could be targeted to specific nematode species known to be affected by this compound and by other antibiotics produced by the bacteria, or these bacteria could be used for other possible effects, such as induced plant resistance.

  11. Some Plant Parasitic Nematodes of Fruit Trees in Northern Khorasan Province, Iran

    Directory of Open Access Journals (Sweden)

    N. Heidarzadeh

    2017-08-01

    Full Text Available Introduction: Nematodes (Phylum Nematoda are considered as one of the most abundant and diverse animals on earth. They are found in terrestrial, freshwater, brackish, and marine environments and play important ecological roles in soil ecosystems. The order Tylenchida includes the largest and economically most important group of plant-parasitic nematodes so they have always received ample taxonomic attention. Many plant parasitic nematode species are important pests of fruit trees. They damage the plant by directly attacking roots and subsequently predisposing them to secondary infections by bacteria, fungi by causing replant and pre-plant problems of orchards and also by transmission of viruses. Plant parasitic nematodes feed on a plant root system, ability to take up water and minerals and to transport nutrients to the shoot. This restricts root growth reduce plant vitality and inhibits shoot growth, the combination of which results in decreased in quality and yield. The economically most important species belong to the genera Meloidogyne, Pratylenchus, criconemella, Logidorus, Xiphinema, Trichodorus and Paratrichodorus and are widely distributed in fruit orchards throughout the world. Nematode species are classically defined on the basis of these qualitative and quantitative characters. Although morphological information might help species diagnostics, these characters are homoplasious features in many cases and do not adequately consider the possibility of convergent evolution. As a result, new species descriptions are increasingly supported by molecular evidence. However, the study of morphology remains a critical necessity as morphology is the primary interface of an organism with its environment with key implications for development and ecology. Therefore, a more robust phylogeny based on a combination of morphological and molecular approaches is needed to clarify important relationships within Tylenchomorpha. The purpose of the present

  12. Effector gene birth in plant parasitic nematodes: Neofunctionalization of a housekeeping glutathione synthetase gene

    Science.gov (United States)

    Lilley, Catherine J.; Maqbool, Abbas; Wu, Duqing; Yusup, Hazijah B.; Jones, Laura M.; Birch, Paul R. J.; Urwin, Peter E.

    2018-01-01

    Plant pathogens and parasites are a major threat to global food security. Plant parasitism has arisen four times independently within the phylum Nematoda, resulting in at least one parasite of every major food crop in the world. Some species within the most economically important order (Tylenchida) secrete proteins termed effectors into their host during infection to re-programme host development and immunity. The precise detail of how nematodes evolve new effectors is not clear. Here we reconstruct the evolutionary history of a novel effector gene family. We show that during the evolution of plant parasitism in the Tylenchida, the housekeeping glutathione synthetase (GS) gene was extensively replicated. New GS paralogues acquired multiple dorsal gland promoter elements, altered spatial expression to the secretory dorsal gland, altered temporal expression to primarily parasitic stages, and gained a signal peptide for secretion. The gene products are delivered into the host plant cell during infection, giving rise to “GS-like effectors”. Remarkably, by solving the structure of GS-like effectors we show that during this process they have also diversified in biochemical activity, and likely represent the founding members of a novel class of GS-like enzyme. Our results demonstrate the re-purposing of an endogenous housekeeping gene to form a family of effectors with modified functions. We anticipate that our discovery will be a blueprint to understand the evolution of other plant-parasitic nematode effectors, and the foundation to uncover a novel enzymatic function. PMID:29641602

  13. PLANT-PARASITIC NEMATODES ON STONE FRUITS AND CITRUS IN LEBANON

    International Nuclear Information System (INIS)

    Ibrahim, S.K.; Azar, I.; Naser, CH.; Akikki, B; Ibrahim, L.

    2016-01-01

    This study aimed to determine the occurrence, distribution of plant parasitic nematodes on stone fruits in Lebanon and to determine the effect of plant extracts on the mortality of several nematode species. A total of 308 soil samples were collected from five different crops. Almost all surveyed areas showed infection with nematodes.The soil infestation rate with nematodes in collected soil samples from all 10 surveyed crops ranged from 66.6 to 100%. Eighteen out of 308 soil samples were free of nematodes (5.8%). All the collected soil samples from nectarine and plum orchards were infested with nematodes (100%), followed by citrus (97.6%), apple (88.7%), pear and quince (85.7%), and cherry (81.4%). The lowest infection (66.6%) was detected on almond and apricot. The level of infestation varied from one area to another and ranged between 0.1and 28 nematodes per 1 g of soil, with the highest number obtained on cherry. Several genera were identified based on morphological characters including:root-knot nematodes (Meloidogynespp.), Tylenchulus, Xiphinema, Rotylenchus, Pratylenchus, and Longidorus. Tylenchulus and Radopholus spp. were the most common on citrus trees, whereas Pratylechus and Meloidogyne spp. were detected almost in all the samples collected from all the crops. Six chopped aromatic plants were tested in pot experiments to control nematodes population densities. The results revealed that carbofuran (nematicide) was the most effective (88.48%) in comparison to the plant materials. Allium sativum gave the highest control (76.52%) followed by Tageta patula (72.0%), Cucurbita maxima (71.84%) and Inula viscosa (63.96%). Origanum syriacum (55.04%)d Thymus (53.72%) were less effective in comparison to the rest of tested plant materials. (author)

  14. Transcriptome analysis in oak uncovers a strong impact of endogenous rhythmic growth on the interaction with plant-parasitic nematodes.

    Science.gov (United States)

    Maboreke, Hazel R; Feldhahn, Lasse; Bönn, Markus; Tarkka, Mika T; Buscot, Francois; Herrmann, Sylvie; Menzel, Ralph; Ruess, Liliane

    2016-08-12

    Pedunculate oak (Quercus robur L.), an important forest tree in temperate ecosystems, displays an endogenous rhythmic growth pattern, characterized by alternating shoot and root growth flushes paralleled by oscillations in carbon allocation to below- and aboveground tissues. However, these common plant traits so far have largely been neglected as a determining factor for the outcome of plant biotic interactions. This study investigates the response of oak to migratory root-parasitic nematodes in relation to rhythmic growth, and how this plant-nematode interaction is modulated by an ectomycorrhizal symbiont. Oaks roots were inoculated with the nematode Pratylenchus penetrans solely and in combination with the fungus Piloderma croceum, and the systemic impact on oak plants was assessed by RNA transcriptomic profiles in leaves. The response of oaks to the plant-parasitic nematode was strongest during shoot flush, with a 16-fold increase in the number of differentially expressed genes as compared to root flush. Multi-layered defence mechanisms were induced at shoot flush, comprising upregulation of reactive oxygen species formation, hormone signalling (e.g. jasmonic acid synthesis), and proteins involved in the shikimate pathway. In contrast during root flush production of glycerolipids involved in signalling cascades was repressed, suggesting that P. penetrans actively suppressed host defence. With the presence of the mycorrhizal symbiont, the gene expression pattern was vice versa with a distinctly stronger effect of P. penetrans at root flush, including attenuated defence, cell and carbon metabolism, likely a response to the enhanced carbon sink strength in roots induced by the presence of both, nematode and fungus. Meanwhile at shoot flush, when nutrients are retained in aboveground tissue, oak defence reactions, such as altered photosynthesis and sugar pathways, diminished. The results highlight that gene response patterns of plants to biotic interactions, both

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

    Directory of Open Access Journals (Sweden)

    S. Molinari

    2004-08-01

    Full Text Available 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.

  16. Nematicidal effect of rhizobacteria on plant-parasitic nematodes associated with vineyards.

    Science.gov (United States)

    Aballay, E; Prodan, S; Zamorano, A; Castaneda-Alvarez, C

    2017-07-01

    The action of metabolites and exoenzymes from rhizobacteria on different plant-parasitic nematodes has an influence on the nematicidal efficacy of the microbe. Seven rhizobacteria, divided into two bacterial groups, were evaluated in vitro for nematicidal activity on Meloidogyne ethiopica and Xiphinema index. The direct effect of their filtrates on egg hatching and juveniles of M. ethiopica as well as mobile stages of X. index was evaluated during a 72-h period. The production of four exoenzymes and two metabolites associated with nematode mortality was investigated. Molecular characterization of three isolates was performed, and the physiological profiles and lipase activity of all isolates were obtained using the BIOLOG EcoPlate system. While chitinase and collagenase were measured using the BIOLOG MT2 plate system, protease, hydrogen cyanide and hydrogen sulphide were directly determined in Petri dishes. Nematode mobile stages exposure to the bacterial filtrate revealed a nematicidal effect up to 93.7% on X. Index and up to 83.3% on M. ethiopica. The control of egg hatching varied between 35 and 85%. A positive correlation was found between the mortality of both nematode mobile stages and the concerted activities of the bacterial enzymes as well as the level of the volatile metabolites. The nematicidal effect of rhizobacteria strains varies by nematode genera and among the developmental stages evaluated.

  17. Plant-parasitic nematodes: towards understanding molecular players in stress responses.

    Science.gov (United States)

    Gillet, François-Xavier; Bournaud, Caroline; Antonino de Souza Júnior, Jose Dijair; Grossi-de-Sa, Maria Fatima

    2017-03-01

    Plant-parasitic nematode interactions occur within a vast molecular plant immunity network. Following initial contact with the host plant roots, plant-parasitic nematodes (PPNs) activate basal immune responses. Defence priming involves the release in the apoplast of toxic molecules derived from reactive species or secondary metabolism. In turn, PPNs must overcome the poisonous and stressful environment at the plant-nematode interface. The ability of PPNs to escape this first line of plant immunity is crucial and will determine its virulence. Nematodes trigger crucial regulatory cytoprotective mechanisms, including antioxidant and detoxification pathways. Knowledge of the upstream regulatory components that contribute to both of these pathways in PPNs remains elusive. In this review, we discuss how PPNs probably orchestrate cytoprotection to resist plant immune responses, postulating that it may be derived from ancient molecular mechanisms. The review focuses on two transcription factors, DAF-16 and SKN-1 , which are conserved in the animal kingdom and are central regulators of cell homeostasis and immune function. Both regulate the unfolding protein response and the antioxidant and detoxification pathways. DAF-16 and SKN-1 target a broad spectrum of Caenorhabditis elegans genes coding for numerous protein families present in the secretome of PPNs. Moreover, some regulatory elements of DAF-16 and SKN-1 from C. elegans have already been identified as important genes for PPN infection. DAF-16 and SKN-1 genes may play a pivotal role in PPNs during parasitism. In the context of their hub status and mode of regulation, we suggest alternative strategies for control of PPNs through RNAi approaches. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

  18. United States Department of Agriculture-Agricultural Research Service research programs on microbes for management of plant-parasitic nematodes.

    Science.gov (United States)

    Meyer, Susan L F

    2003-01-01

    Restrictions on the use of conventional nematicides have increased the need for new methods of managing plant-parasitic nematodes. Consequently, nematode-antagonistic microbes, and active compounds produced by such organisms, are being explored as potential additions to management practices. Programs in this area at the USDA Agricultural Research Service investigate applied biocontrol agents, naturally occurring beneficial soil microbes and natural compounds. Specific research topics include use of plant growth-promoting rhizobacteria and cultural practices for management of root-knot and ring nematodes, determination of management strategies that enhance activity of naturally occurring Pasteuria species (bacterial obligate parasites of nematodes), studies on interactions between biocontrol bacteria and bacterial-feeding nematodes, and screening of microbes for compounds active against plant-parasitic nematodes. Some studies involve biocontrol agents that are active against nematodes and soil-borne plant-pathogenic fungi, or combinations of beneficial bacteria and fungi, to manage a spectrum of plant diseases or to increase efficacy over a broader range of environmental conditions. Effective methods or agents identified in the research programs are investigated as additions to existing management systems for plant-parasitic nematodes.

  19. Discrimination of plant-parasitic nematodes from complex soil communities using ecometagenetics.

    Science.gov (United States)

    Porazinska, Dorota L; Morgan, Matthew J; Gaspar, John M; Court, Leon N; Hardy, Christopher M; Hodda, Mike

    2014-07-01

    Many plant pathogens are microscopic, cryptic, and difficult to diagnose. The new approach of ecometagenetics, involving ultrasequencing, bioinformatics, and biostatistics, has the potential to improve diagnoses of plant pathogens such as nematodes from the complex mixtures found in many agricultural and biosecurity situations. We tested this approach on a gradient of complexity ranging from a few individuals from a few species of known nematode pathogens in a relatively defined substrate to a complex and poorly known suite of nematode pathogens in a complex forest soil, including its associated biota of unknown protists, fungi, and other microscopic eukaryotes. We added three known but contrasting species (Pratylenchus neglectus, the closely related P. thornei, and Heterodera avenae) to half the set of substrates, leaving the other half without them. We then tested whether all nematode pathogens-known and unknown, indigenous, and experimentally added-were detected consistently present or absent. We always detected the Pratylenchus spp. correctly and with the number of sequence reads proportional to the numbers added. However, a single cyst of H. avenae was only identified approximately half the time it was present. Other plant-parasitic nematodes and nematodes from other trophic groups were detected well but other eukaryotes were detected less consistently. DNA sampling errors or informatic errors or both were involved in misidentification of H. avenae; however, the proportions of each varied in the different bioinformatic pipelines and with different parameters used. To a large extent, false-positive and false-negative errors were complementary: pipelines and parameters with the highest false-positive rates had the lowest false-negative rates and vice versa. Sources of error identified included assumptions in the bioinformatic pipelines, slight differences in primer regions, the number of sequence reads regarded as the minimum threshold for inclusion in analysis

  20. The dual effects of root-cap exudates on nematodes: from quiescence in plant-parasitic nematodes to frenzy in entomopathogenic nematodes.

    Science.gov (United States)

    Hiltpold, Ivan; Jaffuel, Geoffrey; Turlings, Ted C J

    2015-02-01

    To defend themselves against herbivores and pathogens, plants produce numerous secondary metabolites, either constitutively or de novo in response to attacks. An intriguing constitutive example is the exudate produced by certain root-cap cells that can induce a state of reversible quiescence in plant-parasitic nematodes, thereby providing protection against these antagonists. The effect of such root exudates on beneficial entomopathogenic nematodes (EPNs) remains unclear, but could potentially impair their use in pest management programmes. We therefore tested how the exudates secreted by green pea (Pisum sativum) root caps affect four commercial EPN species. The exudates induced reversible quiescence in all EPN species tested. Quiescence levels varied with the green pea cultivars tested. Notably, after storage in root exudate, EPN performance traits were maintained over time, whereas performances of EPNs stored in water rapidly declined. In sharp contrast to high concentrations, lower concentrations of the exudate resulted in a significant increase in EPN activity and infectiousness, but still reduced the activity of two plant-parasitic nematode species. Our study suggests a finely tuned dual bioactivity of the exudate from green pea root caps. Appropriately formulated, it can favour long-term storage of EPNs and boost their infectiousness, while it may also be used to protect plants from plant-parasitic nematodes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  1. The transcriptome of Nacobbus aberrans reveals insights into the evolution of sedentary endoparasitism in plant-parasitic nematodes.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J; Danchin, Etienne G J; Rancurel, Corinne; Cock, Peter J A; Urwin, Peter E; Jones, John T

    2014-08-13

    Within the phylum Nematoda, plant-parasitism is hypothesized to have arisen independently on at least four occasions. The most economically damaging plant-parasitic nematode species, and consequently the most widely studied, are those that feed as they migrate destructively through host roots causing necrotic lesions (migratory endoparasites) and those that modify host root tissue to create a nutrient sink from which they feed (sedentary endoparasites). The false root-knot nematode Nacobbus aberrans is the only known species to have both migratory endoparasitic and sedentary endoparasitic stages within its life cycle. Moreover, its sedentary stage appears to have characteristics of both the root-knot and the cyst nematodes. We present the first large-scale genetic resource of any false-root knot nematode species. We use RNAseq to describe relative abundance changes in all expressed genes across the life cycle to provide interesting insights into the biology of this nematode as it transitions between modes of parasitism. A multigene phylogenetic analysis of N. aberrans with respect to plant-parasitic nematodes of all groups confirms its proximity to both cyst and root-knot nematodes. We present a transcriptome-wide analysis of both lateral gene transfer events and the effector complement. Comparing parasitism genes of typical root-knot and cyst nematodes to those of N. aberrans has revealed interesting similarities. Importantly, genes that were believed to be either cyst nematode, or root-knot nematode, "specific" have both been identified in N. aberrans. Our results provide insights into the characteristics of a common ancestor and the evolution of sedentary endoparasitism of plants by nematodes. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  2. The Transcriptome of Nacobbus aberrans Reveals Insights into the Evolution of Sedentary Endoparasitism in Plant-Parasitic Nematodes

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J.; Danchin, Etienne G. J.; Rancurel, Corinne; Cock, Peter J. A.; Urwin, Peter E.; Jones, John T.

    2014-01-01

    Within the phylum Nematoda, plant-parasitism is hypothesized to have arisen independently on at least four occasions. The most economically damaging plant-parasitic nematode species, and consequently the most widely studied, are those that feed as they migrate destructively through host roots causing necrotic lesions (migratory endoparasites) and those that modify host root tissue to create a nutrient sink from which they feed (sedentary endoparasites). The false root-knot nematode Nacobbus aberrans is the only known species to have both migratory endoparasitic and sedentary endoparasitic stages within its life cycle. Moreover, its sedentary stage appears to have characteristics of both the root-knot and the cyst nematodes. We present the first large-scale genetic resource of any false-root knot nematode species. We use RNAseq to describe relative abundance changes in all expressed genes across the life cycle to provide interesting insights into the biology of this nematode as it transitions between modes of parasitism. A multigene phylogenetic analysis of N. aberrans with respect to plant-parasitic nematodes of all groups confirms its proximity to both cyst and root-knot nematodes. We present a transcriptome-wide analysis of both lateral gene transfer events and the effector complement. Comparing parasitism genes of typical root-knot and cyst nematodes to those of N. aberrans has revealed interesting similarities. Importantly, genes that were believed to be either cyst nematode, or root-knot nematode, “specific” have both been identified in N. aberrans. Our results provide insights into the characteristics of a common ancestor and the evolution of sedentary endoparasitism of plants by nematodes. PMID:25123114

  3. Plant parasitic nematode effectors target host defence and nuclear functions to establish feeding cells

    Directory of Open Access Journals (Sweden)

    Michaël eQuentin

    2013-03-01

    Full Text Available Plant parasitic nematodes are microscopic worms, the most damaging species of which have adopted a sedentary lifestyle within their hosts. These obligate endoparasites have a biotrophic relationship with plants, in which they induce the differentiation of root cells into hypertrophied, multinucleate feeding cells. Effectors synthesised in the oesophageal glands of the nematode are injected into the plant cells via the syringe-like stylet and play a key role in manipulating the host machinery. The establishment of specialized feeding cells requires these effectors to modulate many aspects of plant cell morphogenesis and physiology, including defence responses. This cell reprogramming requires changes to host nuclear processes. Some proteins encoded by parasitism genes target host nuclei. Several of these proteins were immunolocalised within feeding cell nuclei or shown to interact with host nuclear proteins. Comparative genomics and functional analyses are gradually revealing the roles of nematode effectors. We describe here these effectors and their hypothesised roles in the unique feeding behaviour of these pests.

  4. Description and identification of four species of plant parasitic nematodes associated with grassland, fruit trees and maize in Romania.

    Science.gov (United States)

    Badi, M; Geraert, E

    2002-01-01

    Three species of plant parasitic nematodes present in two romanian soil samples were described and identified in the present study. The species belong to order tylenchida and to taxonomical families Tylenchidae (Basiria aberrans) and Belonolaimidae (Tylenchorhynchus georgiensis and Merlinius brevidens). The identification of the present specimens was based on the classical taxonomy, following morphological and morphometrical characters in the species specific identification keys.

  5. Characterization of the Pratylenchus penetrans transcriptome including data mining of putative nematode genes involved in plant parasitism

    Science.gov (United States)

    The root lesion nematode Pratylenchus penetrans is considered one of the most economically important species within the genus. Host range studies have shown that nearly 400 plant species can be parasitized by this species. To obtain insight into the transcriptome of this migratory plant-parasitic ne...

  6. Evaluation of Clonostachys rosea for Control of Plant-Parasitic Nematodes in Soil and in Roots of Carrot and Wheat.

    Science.gov (United States)

    Iqbal, Mudassir; Dubey, Mukesh; McEwan, Kerstin; Menzel, Uwe; Franko, Mikael Andersson; Viketoft, Maria; Jensen, Dan Funck; Karlsson, Magnus

    2018-01-01

    Biological control is a promising approach to reduce plant diseases caused by nematodes. We tested the effect of the fungus Clonostachys rosea strain IK726 inoculation on nematode community composition in a naturally nematode infested soil in a pot experiment, and the effect of C. rosea on plant health. The numbers of plant-parasitic nematode genera extracted from soil and plant roots decreased by 40 to 73% when C. rosea was applied, while genera of nonparasitic nematodes were not affected. Soil inoculation of C. rosea increased fresh shoot weight and shoot length of wheat plants by 20 and 24%, respectively, while only shoot dry weight increased by 48% in carrots. Light microscopy of in vitro C. rosea-nematode interactions did not reveal evidence of direct parasitism. However, culture filtrates of C. rosea growing in potato dextrose broth, malt extract broth and synthetic nutrient broth exhibited toxicity toward nematodes and immobilized 57, 62, and 100% of the nematodes, respectively, within 48 h. This study demonstrates that C. rosea can control plant-parasitic nematodes and thereby improve plant growth. The most likely mechanism responsible for the antagonism is antibiosis through production of nematicidal compounds, rather than direct parasitism.

  7. Regulation of Population Densities of Heterodera cajani and Other Plant-Parasitic Nematodes by Crop Rotations on Vertisols, in Semi-Arid Tropical Production Systems in India

    Science.gov (United States)

    Sharma, S. B.; Rego, T. J.; Mohiuddin, M.; Rao, V. N.

    1996-01-01

    The significance of double crop (intercrop and sequential crop), single crop (rainy season crop fallow from June to September), and rotations on densities of Heterodera cajani, Helicotylenchus retusus, and Rotylenchulus reniformis was studied on Vertisol (Typic Pellusterts) between 1987 and 1993. Cowpea (Vigna sinensis), mungbean (Phaseolus aureus), and pigeonpea (Cajanus cajan) greatly increased the population densities of H. cajani and suppressed the population densities of other plant-parasitic nematodes. Mean population densities of H. cajani were about 8 times lower in single crop systems than in double crop systems, with pigeonpea as a component intercrop. Plots planted to sorghum, safflower, and chickpea in the preceding year contained fewer H. cajani eggs and juveniles than did plots previously planted to pigeonpea, cowpea, or mungbean. Continuous cropping of sorghum in the rainy season and safflower in the post-rainy season markedly reduced the population density of H. cajani. Sorghum, safflower, and chickpea favored increased population densities of H. retusus. Adding cowpea to the system resulted in a significant increase in the densities of R. reniformis. Mean densities of total plant-parasitic nematodes were three times greater in double crop systems, with pigeonpea as a component intercrop than in single crop systems with rainy season fallow component. Cropping systems had a regulatory effect on the nematode populations and could be an effective nematode management tactic. Intercropping of sorghum with H. cajani tolerant pigeonpea could be effective in increasing the productivity of traditional production systems in H. cajani infested regions. PMID:19277141

  8. Combinations of biocontrol agents for management of plant-parasitic nematodes and soilborne plant-pathogenic fungi.

    Science.gov (United States)

    Meyer, Susan L F; Roberts, Daniel P

    2002-03-01

    Numerous microbes are antagonistic to plant-parasitic nematodes and soilborne plant-pathogenic fungi, but few of these organisms are commercially available for management of these pathogens. Inconsistent performance of applied biocontrol agents has proven to be a primary obstacle to the development of successful commercial products. One of the strategies for overcoming inconsistent performance is to combine the disease-suppressive activity of two (or more) beneficial microbes in a biocontrol preparation. Such combinations have potential for more extensive colonization of the rhizosphere, more consistent expression of beneficial traits under a broad range of soil conditions, and antagonism to a larger number of plant pests or pathogens than strains applied individually. Conversely, microbes applied in combination also may have antagonistic interactions with each other. Increased, decreased, and unaltered suppression of the target pathogen or pest has been observed when biocontrol microbes have been applied in combination. Unfortunately, the ecological basis for increased or decreased suppression has not been determined in many cases and needs further consideration. The complexity of interactions involved in the application of multiple organisms for biological control has slowed progress toward development of successful formulations. However, this approach has potential for overcoming some of the efficacy problems that occur with application of individual biocontrol agents.

  9. Heterozygote deficits in cyst plant-parasitic nematodes: possible causes and consequences.

    Science.gov (United States)

    Montarry, Josselin; Jan, Pierre-Loup; Gracianne, Cecile; Overall, Andrew D J; Bardou-Valette, Sylvie; Olivier, Eric; Fournet, Sylvain; Grenier, Eric; Petit, Eric J

    2015-04-01

    Deviations of genotypic frequencies from Hardy-Weinberg equilibrium (HWE) expectations could reveal important aspects of the biology of populations. Deviations from HWE due to heterozygote deficits have been recorded for three plant-parasitic nematode species. However, it has never been determined whether the observed deficits were due (i) to the presence of null alleles, (ii) to a high level of consanguinity and/or (iii) to a Wahlund effect. The aim of the present work was, while taking into the possible confounding effect of null alleles, to disentangle consanguinity and Wahlund effect in natural populations of those three economically important cyst nematodes using microsatellite markers: Globodera pallida, G. tabacum and Heterodera schachtii, pests of potato, tobacco and sugar beet, respectively. The results show a consistent pattern of heterozygote deficiency in the three nematode species sampled at the spatial scale of the host plant. We demonstrate that the prevalence of null alleles is weak and that heterozygote deficits do not have a single origin. Our results suggested that it is restricted dispersal that leads to heterozygote deficits through both consanguinity and substructure, which effects can be linked to soil movement, cyst density, and the number of generations per year. We discuss potential implications for the durability of plant resistances that are used to protect crops against parasites in which mating between relatives occur. While consanguineous mating leads to homozygosity at all loci, including loci governing avirulence/virulence, which favours the expression of virulence when recessive, the Wahlund effect is expected to have no particular effect on the adaptation of nematodes to resistances. © 2015 John Wiley & Sons Ltd.

  10. Microaspiration of esophageal gland cells and cDNA library construction for identifying parasitism genes of plant-parasitic nematodes.

    Science.gov (United States)

    Hussey, Richard S; Huang, Guozhong; Allen, Rex

    2011-01-01

    Identifying parasitism genes encoding proteins secreted from a plant-parasitic nematode's esophageal gland cells and injected through its stylet into plant tissue is the key to understanding the molecular basis of nematode parasitism of plants. Parasitism genes have been cloned by directly microaspirating the cytoplasm from the esophageal gland cells of different parasitic stages of cyst or root-knot nematodes to provide mRNA to create a gland cell-specific cDNA library by long-distance reverse-transcriptase polymerase chain reaction. cDNA clones are sequenced and deduced protein sequences with a signal peptide for secretion are identified for high-throughput in situ hybridization to confirm gland-specific expression.

  11. Anatomical Alterations in Plant Tissues Induced by Plant-Parasitic Nematodes

    Directory of Open Access Journals (Sweden)

    Juan E. Palomares-Rius

    2017-11-01

    Full Text Available Plant-parasitic nematodes (PPNs interact with plants in different ways, for example, through subtle feeding behavior, migrating destructively through infected tissues, or acting as virus-vectors for nepoviruses. They are all obligate biotrophic parasites as they derive their nutrients from living cells which they modify using pharyngeal gland secretions prior to food ingestion. Some of them can also shield themselves against plant defenses to sustain a relatively long lasting interaction while feeding. This paper is centered on cell types or organs that are newly induced in plants during PPN parasitism, including recent approaches to their study based on molecular biology combined with cell biology-histopathology. This issue has already been reviewed extensively for major PPNs (i.e., root-knot or cyst nematodes, but not for other genera (viz. Nacobbus aberrans, Rotylenchulus spp.. PPNs have evolved with plants and this co-evolution process has allowed the induction of new types of plant cells necessary for their parasitism. There are four basic types of feeding cells: (i non-hypertrophied nurse cells; (ii single giant cells; (iii syncytia; and (iv coenocytes. Variations in the structure of these cells within each group are also present between some genera depending on the nematode species viz. Meloidogyne or Rotylenchulus. This variability of feeding sites may be related in some way to PPN life style (migratory ectoparasites, sedentary ectoparasites, migratory ecto-endoparasites, migratory endoparasites, or sedentary endoparasites. Apart from their co-evolution with plants, the response of plant cells and roots are closely related to feeding behavior, the anatomy of the nematode (mainly stylet size, which could reach different types of cells in the plant, and the secretory fluids produced in the pharyngeal glands. These secretory fluids are injected through the stylet into perforated cells where they modify plant cytoplasm prior to food removal

  12. Assessment of weeds as alternative hosts of plant-parasitic nematodes in coffee plantations in Costa Rica

    OpenAIRE

    Walter Peraza-Padilla; Martha Orozco-Aceves

    2018-01-01

    There is potential for weeds to be alternative hosts of plant-parasitic nematodes (PPN), but a methodology that assesses the phytosanitary risk derived from the presence of weeds in plantations is not available. This research was conducted in order to determine if the presence of weeds in coffee plantations (organic and conventional) represented a phytosanitary risk due to their role as alternative hosts of PPN. The research was developed into two plantation located in Aserrí, San José, Costa...

  13. The effects of Brassica green manures on plant parasitic and free living nematodes used in combination with reduced rates of synthetic nematicides.

    Science.gov (United States)

    Riga, Ekaterini

    2011-06-01

    Brassica plants once incorporated into soil as green manures have recently been shown to have biofumigant properties and have the potential of controlling plant-parasitic nematodes. In Washington State, plant-parasitic nematodes are successfully managed with synthetic nematicides. However, some of the synthetic nematicides became unavailable recently or their supply is limited leaving growers with few choices to control plant-parasitic nematodes. The objective of this project was to evaluate the effects of Brassica green manures on their own and in combination with reduced rates of synthetic nematicides on plant-parasitic nematodes and free living nematodes. In a greenhouse experiment and field trials in three seasons, Brassica green manures in combination with half the recommended rate of 1,3-dichloropropene (1,3-D, Telone) reduced root knot nematode, Meloidogyne chitwoodi to below detection levels, and reduced lesion nematodes, Pratylenchus penetrans and stubby root nematodes, Paratrichodorus allius, to below economic thresholds. The combination treatments did not affect the beneficial free-living nematode populations and the non-pathogenic Pseudomonas. The total cost of growing and soil-incorporating Brassica crops as green manures in combination with reduced rates of 1,3-D was approximately 35% lower than the present commercial costs for application for the full rate of this fumigant. Integrating conventional management practices with novel techniques fosters sustainability of production systems and can increase economic benefit to producers while reducing chemical input.

  14. The genome and life-stage specific transcriptomes of Globodera pallida elucidate key aspects of plant parasitism by a cyst nematode.

    Science.gov (United States)

    Cotton, James A; Lilley, Catherine J; Jones, Laura M; Kikuchi, Taisei; Reid, Adam J; Thorpe, Peter; Tsai, Isheng J; Beasley, Helen; Blok, Vivian; Cock, Peter J A; Eves-van den Akker, Sebastian; Holroyd, Nancy; Hunt, Martin; Mantelin, Sophie; Naghra, Hardeep; Pain, Arnab; Palomares-Rius, Juan E; Zarowiecki, Magdalena; Berriman, Matthew; Jones, John T; Urwin, Peter E

    2014-03-03

    Globodera pallida is a devastating pathogen of potato crops, making it one of the most economically important plant parasitic nematodes. It is also an important model for the biology of cyst nematodes. Cyst nematodes and root-knot nematodes are the two most important plant parasitic nematode groups and together represent a global threat to food security. We present the complete genome sequence of G. pallida, together with transcriptomic data from most of the nematode life cycle, particularly focusing on the life cycle stages involved in root invasion and establishment of the biotrophic feeding site. Despite the relatively close phylogenetic relationship with root-knot nematodes, we describe a very different gene family content between the two groups and in particular extensive differences in the repertoire of effectors, including an enormous expansion of the SPRY domain protein family in G. pallida, which includes the SPRYSEC family of effectors. This highlights the distinct biology of cyst nematodes compared to the root-knot nematodes that were, until now, the only sedentary plant parasitic nematodes for which genome information was available. We also present in-depth descriptions of the repertoires of other genes likely to be important in understanding the unique biology of cyst nematodes and of potential drug targets and other targets for their control. The data and analyses we present will be central in exploiting post-genomic approaches in the development of much-needed novel strategies for the control of G. pallida and related pathogens.

  15. Understanding the interaction between an obligate hyperparasitic bacterium, Pasteuria penetrans and its obligate plant-parasitic nematode host, Meloidogyne spp.

    Science.gov (United States)

    Davies, Keith G

    2009-01-01

    Pasteuria penetrans is an endospore-forming bacterium, which is a hyperparasite of root-knot nematodes Meloidogyne spp. that are economically important pests of a wide range of crops. The life cycle of the bacterium and nematode are described with emphasis on the bacterium's potential as a biocontrol agent. Two aspects that currently prohibit the commercial development of the bacterium as a biocontrol agent are the inability to culture it outside its host and its host specificity. Vegetative growth of the bacterium is possible in vitro; however, getting the vegetative stages of the bacterium to enter sporogenesis has been problematic. Insights from genomic survey sequences regarding the role of cation concentration and the phosphorylation of Spo0F have proved useful in inducing vegetative bacteria to sporulate. Similarly, genomic data have also proved useful in understanding the attachment of endospores to the cuticle of infective nematode juveniles, and a Velcro-like model of spore attachment is proposed that involves collagen-like fibres on the surface of the endospore interacting with mucins on the nematode cuticle. Ecological studies of the interactions between Daphnia and Pasteuria ramosa are examined and similarities are drawn between the co-evolution of virulence in the Daphnia system and that of plant-parasitic nematodes.

  16. Evolution of GHF5 endoglucanase gene structure in plant-parasitic nematodes: no evidence for an early domain shuffling event.

    Science.gov (United States)

    Kyndt, Tina; Haegeman, Annelies; Gheysen, Godelieve

    2008-11-03

    Endo-1,4-beta-glucanases or cellulases from the glycosyl hydrolase family 5 (GHF5) have been found in numerous bacteria and fungi, and recently also in higher eukaryotes, particularly in plant-parasitic nematodes (PPN). The origin of these genes has been attributed to horizontal gene transfer from bacteria, although there still is a lot of uncertainty about the origin and structure of the ancestral GHF5 PPN endoglucanase. It is not clear whether this ancestral endoglucanase consisted of the whole gene cassette, containing a catalytic domain and a carbohydrate-binding module (CBM, type 2 in PPN and bacteria) or only of the catalytic domain while the CBM2 was retrieved by domain shuffling later in evolution. Previous studies on the evolution of these genes have focused primarily on data of sedentary nematodes, while in this study, extra data from migratory nematodes were included. Two new endoglucanases from the migratory nematodes Pratylenchus coffeae and Ditylenchus africanus were included in this study. The latter one is the first gene isolated from a PPN of a different superfamily (Sphaerularioidea); all previously known nematode endoglucanases belong to the superfamily Tylenchoidea (order Rhabditida). Phylogenetic analyses were conducted with the PPN GHF5 endoglucanases and homologous endoglucanases from bacterial and other eukaryotic lineages such as beetles, fungi and plants. No statistical incongruence between the phylogenetic trees deduced from the catalytic domain and the CBM2 was found, which could suggest that both domains have evolved together. Furthermore, based on gene structure data, we inferred a model for the evolution of the GHF5 endoglucanase gene structure in plant-parasitic nematodes. Our data confirm a close relationship between Pratylenchus spp. and the root knot nematodes, while some Radopholus similis endoglucanases are more similar to cyst nematode genes. We conclude that the ancestral PPN GHF5 endoglucanase gene most probably consisted of

  17. Evolution of GHF5 endoglucanase gene structure in plant-parasitic nematodes: no evidence for an early domain shuffling event

    Directory of Open Access Journals (Sweden)

    Gheysen Godelieve

    2008-11-01

    Full Text Available Abstract Background Endo-1,4-beta-glucanases or cellulases from the glycosyl hydrolase family 5 (GHF5 have been found in numerous bacteria and fungi, and recently also in higher eukaryotes, particularly in plant-parasitic nematodes (PPN. The origin of these genes has been attributed to horizontal gene transfer from bacteria, although there still is a lot of uncertainty about the origin and structure of the ancestral GHF5 PPN endoglucanase. It is not clear whether this ancestral endoglucanase consisted of the whole gene cassette, containing a catalytic domain and a carbohydrate-binding module (CBM, type 2 in PPN and bacteria or only of the catalytic domain while the CBM2 was retrieved by domain shuffling later in evolution. Previous studies on the evolution of these genes have focused primarily on data of sedentary nematodes, while in this study, extra data from migratory nematodes were included. Results Two new endoglucanases from the migratory nematodes Pratylenchus coffeae and Ditylenchus africanus were included in this study. The latter one is the first gene isolated from a PPN of a different superfamily (Sphaerularioidea; all previously known nematode endoglucanases belong to the superfamily Tylenchoidea (order Rhabditida. Phylogenetic analyses were conducted with the PPN GHF5 endoglucanases and homologous endoglucanases from bacterial and other eukaryotic lineages such as beetles, fungi and plants. No statistical incongruence between the phylogenetic trees deduced from the catalytic domain and the CBM2 was found, which could suggest that both domains have evolved together. Furthermore, based on gene structure data, we inferred a model for the evolution of the GHF5 endoglucanase gene structure in plant-parasitic nematodes. Our data confirm a close relationship between Pratylenchus spp. and the root knot nematodes, while some Radopholus similis endoglucanases are more similar to cyst nematode genes. Conclusion We conclude that the ancestral

  18. EFFICACY OF ENDOPHYTIC BACTERIA IN REDUCING PLANT PARASITIC NEMATODE Pratylenchus brachyurus

    Directory of Open Access Journals (Sweden)

    Rita Harni

    2014-04-01

    Full Text Available Pratylenchus brachyurus is a major parasitic nematode on patchouli that reduces plant production up to 85%. The use of endophytic bacteria is promising for controlling nematode and promoting plant growth through production of phytohormones and enhancing the availability of soil nutrients. The objective of the study was to evaluate the efficacy of endophytic bacteria to control P. brachyurus on patchouli plant and its influence on plant productions (plant fresh weight and patchouli oil. The study was conducted at Cimanggu Experimental Garden and Laboratory of the Indonesian Spice and Medicinal Crops Research Institute (ISMECRI, Bogor, West Java. The experi-ment was designed in a randomized block with seven treatments and eight replications; each replication consisted of 10 plants. The treatments evaluated were five isolates of endophytic bacteria (Achromobacter xylosoxidans TT2, Alcaligenes faecalis NJ16, Pseudomonas putida EH11, Bacillus cereus MSK and Bacillus subtilis NJ57, synthetic nematicide as a reference, and non-treated plant as a control.  Four-week old patchouli plants of cv. Sidikalang were treated by soaking the roots in suspension of endophytic bacteria (109 cfu  ml-1 for one hour before trans-planting to the field. At one month after planting, the plants were drenched with the bacterial suspension as much as 100 ml per plant. The results showed that applications of the endophytic bacteria could suppress the nematode populations (52.8-80% and increased plant weight (23.62-57.48% compared to the control. The isolate of endophytic bacterium Achromobacter xylosoxidans TT2 was the best and comparable with carbofuran.

  19. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes.

    Science.gov (United States)

    Danchin, Etienne G J; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Da Rocha, Martine; Bajew, Simon; Neilson, Roy; Guzeeva, Elena Sokolova; Da Silva, Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Johannes; Jones, John T; den Akker, Sebastian Eves-van

    2017-10-23

    Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus , representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus , respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum.

  20. Species Composition and Structure of the Communities of Plant-Parasitic and Free-Living Soil Nematodes in the Greenhouses of Botanical Gardens of Ukraine

    Directory of Open Access Journals (Sweden)

    Gubin A.I.

    2014-07-01

    Full Text Available Species Composition and Structure of the Communities of Plant-Parasitic and Free-Living Soil Nematodes in the Greenhouses of Botanical Gardens of Ukraine. Gubin, A. I., Sigareva, D. D. — In greenhouses of botanical gardens of Ukraine 81 species of nematodes were found. The richest by the number of species was Tylenchida order that was presented by 25 species (31 % of species composition. The dominant group of nematodes was plant-parasitic (most frequent was Rotylenchus robustus (de Man, 1876 Filipjev, 1936 and Meloidogyne incognita (Kofoid et White, 1919 Chitwood, 1949. The group of saprobiotic nematodes, which was presented by 52 species (64 %, appeared to be the richest by the number of species. It is shown, that formation of nematode communities in greenhouses of botanical gardens was caused by the interaction of many related factors, crucial of which is the composition of plant collections. The structure of communities is quite constant and almost independent of the quantity of nematodes species. Plant-parasitic species dominate by the number and frequency of detection, and represent a kind of a core of nematode communities.

  1. Species discovery and diversity in Lobocriconema (Criconematidae: Nematoda) and related plant-parasitic nematodes from North American ecoregions.

    Science.gov (United States)

    Powers, T O; Bernard, E C; Harris, T; Higgins, R; Olson, M; Olson, S; Lodema, M; Matczyszyn, J; Mullin, P; Sutton, L; Powers, K S

    2016-03-03

    deciduous forest, but definitive glacial refugia for this group of plant parasitic nematodes have yet to be identified. Unlike agricultural pest species of plant-parasitic nematodes, there is little evidence of long-distance dispersal in Lobocriconema as revealed by haplotype distribution. Most haplotype groups were characterized by low levels of intragroup genetic variation and large genetic distances between haplotype groups. The localization of nematode haplotypes together with their characteristic plant communities could provide insight into the historical formation of these belowground biotic communities.

  2. Effect of Tropical Rotation Crops on Meloidogyne incognita and Other Plant-Parasitic Nematodes.

    Science.gov (United States)

    McSorley, R; Dickson, D W

    1995-12-01

    In a field experiment conducted on sandy soil in Florida during the 1993 season, rotation crops of castor (Ricinus communis), velvetbean (Mucuna deeringina), 'Mississippi Silver' cowpea (Vigna unguiculata), American jointvetch (Aeschynomene americana), 'Dehapine 51' cotton (Gossypium hirsutum), and 'SX-17' sorghum-sudangrass (Sorghum bicolor x S. sudanense) were effective in maintaining low population densities (450/100 cm(3) soil) resulted after 'Clemson Spineless' okra (Hibiscus esculentus) and 'Kirby' soybean (Glycine max). Following a winter cover crop of rye (Secale cereale), densities of M. incognita following the six most effective rotation crops (1993 season) remained relatively low (crop planted in 1994, but increased by the end of the eggplant crop. The rotation crops planted during 1993 had little effect on yield of eggplant in 1994. Eggplant yield was inversely correlated with preplant densities (Pi) of Belonolaimus longicaudatus (r = -0.282; P crop cultivars were lower (P crops intended for suppression of individual Meloidogyne spp. be evaluated for their response to other nematode pests as well.

  3. The genome and life-stage specific transcriptomes of Globodera pallida elucidate key aspects of plant parasitism by a cyst nematode

    KAUST Repository

    Cotton, James A

    2014-03-03

    Background: Globodera pallida is a devastating pathogen of potato crops, making it one of the most economically important plant parasitic nematodes. It is also an important model for the biology of cyst nematodes. Cyst nematodes and root-knot nematodes are the two most important plant parasitic nematode groups and together represent a global threat to food security. Results: We present the complete genome sequence of G. pallida, together with transcriptomic data from most of the nematode life cycle, particularly focusing on the life cycle stages involved in root invasion and establishment of the biotrophic feeding site. Despite the relatively close phylogenetic relationship with root-knot nematodes, we describe a very different gene family content between the two groups and in particular extensive differences in the repertoire of effectors, including an enormous expansion of the SPRY domain protein family in G. pallida, which includes the SPRYSEC family of effectors. This highlights the distinct biology of cyst nematodes compared to the root-knot nematodes that were, until now, the only sedentary plant parasitic nematodes for which genome information was available. We also present in-depth descriptions of the repertoires of other genes likely to be important in understanding the unique biology of cyst nematodes and of potential drug targets and other targets for their control. Conclusions: The data and analyses we present will be central in exploiting post-genomic approaches in the development of much-needed novel strategies for the control of G. pallida and related pathogens. 2014 Cotton et al.; licensee BioMed Central Ltd.

  4. Development and reproductive potential of Tyrophagus putrescentiae (Acari: Acaridae) on plant-parasitic nematodes and artificial diets.

    Science.gov (United States)

    Abou El-Atta, Doaa Abd El-Maksoud; Osman, Mohamed Ali

    2016-04-01

    This study investigated development, reproduction and life table parameters of the astigmatid mold mite Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) feeding on egg-masses or adult females of the nematode Meloidogyne incognita, egg-masses of the nematode Rotylenchulus reniformis, ras cheese or yeast at 25 ± 1 °C, 70 ± 10 % RH in the dark. Immature developmental times were shorter when the mite was fed females of M. incognita followed by yeast. Different prey/diet types had no significant effect on longevity and lifespan of both males and females. Daily oviposition rate (eggs/female/day) was highest for mites fed yeast (20.8 ± 1.8 eggs) and lowest for mites fed females of M. incognita (6.6 ± 0.5). Intrinsic rate of natural increase (r m) was highest for mites fed yeast compared to other prey/diet; no significant differences in r m were observed among mites fed on non-yeast diets. This result may suggest a role of T. putrescentiae as biocontrol agent of plant-parasitic nematodes and the yeast may be used for mite mass-production purposes.

  5. A Secreted SPRY Domain-Containing Protein (SPRYSEC) from the Plant-Parasitic Nematode Globodera rostochiensis Interacts with a CC-NB-LRR Protein from a Susceptible Tomato

    NARCIS (Netherlands)

    Rehman, S.; Postma, W.J.; Tytgat, T.O.G.; Prins, J.C.P.; Qin Ling,; Overmars, H.A.; Vossen, J.; Spiridon, L.N.; Petrescu, A.J.; Goverse, A.; Bakker, J.; Smant, G.

    2009-01-01

    Esophageal gland secretions from nematodes are believed to include effectors that play important roles in plant parasitism. We have identified a novel gene family encoding secreted proteins specifically expressed in the dorsal esophageal gland of Globodera rostochiensis early in the parasitic cycle,

  6. The genomic organization of four b-1,4-endoglucanase genes in plant-parasitic cyst nematodes and its evolutionary implications.

    NARCIS (Netherlands)

    Yan, Y.; Smant, G.; Stokkermans, J.P.W.G.; Qin Ling,; Baum, T.J.; Schots, A.; Davis, E.L.

    1998-01-01

    The genomic organization of genes encoding -1,4-endoglucanases (cellulases) from the plant-parasitic cyst nematodes Heterodera glycines and Globodera rostochiensis (HG-eng1, Hg-eng2, GR-eng1, and GR-eng2) was investigated. HG-eng1 and GR-eng1 both contained eight introns and structural domains of

  7. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

    NARCIS (Netherlands)

    Danchin, Etienne G.J.; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Rocha, Da Martine; Bajew, Simon; Neilson, Roy; Sokolova, Elena; Silva, Da Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Hans; Jones, John T.; Eves-van den Akker, Sebastian

    2017-01-01

    Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been

  8. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

    Directory of Open Access Journals (Sweden)

    Etienne G.J. Danchin

    2017-10-01

    Full Text Available Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus, representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus, respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum.

  9. The Transcriptomes of Xiphinema index and Longidorus elongatus Suggest Independent Acquisition of Some Plant Parasitism Genes by Horizontal Gene Transfer in Early-Branching Nematodes

    Science.gov (United States)

    Danchin, Etienne G.J.; Perfus-Barbeoch, Laetitia; Rancurel, Corinne; Thorpe, Peter; Da Rocha, Martine; Bajew, Simon; Neilson, Roy; Sokolova (Guzeeva), Elena; Da Silva, Corinne; Guy, Julie; Labadie, Karine; Esmenjaud, Daniel; Helder, Johannes; Jones, John T.

    2017-01-01

    Nematodes have evolved the ability to parasitize plants on at least four independent occasions, with plant parasites present in Clades 1, 2, 10 and 12 of the phylum. In the case of Clades 10 and 12, horizontal gene transfer of plant cell wall degrading enzymes from bacteria and fungi has been implicated in the evolution of plant parasitism. We have used ribonucleic acid sequencing (RNAseq) to generate reference transcriptomes for two economically important nematode species, Xiphinema index and Longidorus elongatus, representative of two genera within the early-branching Clade 2 of the phylum Nematoda. We used a transcriptome-wide analysis to identify putative horizontal gene transfer events. This represents the first in-depth transcriptome analysis from any plant-parasitic nematode of this clade. For each species, we assembled ~30 million Illumina reads into a reference transcriptome. We identified 62 and 104 transcripts, from X. index and L. elongatus, respectively, that were putatively acquired via horizontal gene transfer. By cross-referencing horizontal gene transfer prediction with a phylum-wide analysis of Pfam domains, we identified Clade 2-specific events. Of these, a GH12 cellulase from X. index was analysed phylogenetically and biochemically, revealing a likely bacterial origin and canonical enzymatic function. Horizontal gene transfer was previously shown to be a phenomenon that has contributed to the evolution of plant parasitism among nematodes. Our findings underline the importance and the extensiveness of this phenomenon in the evolution of plant-parasitic life styles in this speciose and widespread animal phylum. PMID:29065523

  10. Nematicidal effect of volatile organic compounds (VOCs on the plant-parasitic nematode Meloidogyne javanica

    Directory of Open Access Journals (Sweden)

    Mauricio Batista Fialho

    2012-06-01

    Full Text Available Previous studies have demonstrated that volatile organic compounds (VOCs, produced by the yeast Saccharomyces cerevisiae, were able to inhibit the development of phytopathogenic fungi. In this context, the nematicidal potential of the synthetic mixture of VOCs, constituted of alcohols and esters, was evaluated for the control of the root-knot nematode Meloidogyne javanica, which causes losses to crops of high economic value. The fumigation of substrate containing second-stage juveniles with VOCs exhibited nematicidal effect higher than 30% for the lowest concentration tested (33.3 µL g-1 substrate, whereas at 66.6 and 133.3 µL g-1 substrate, the nematode mortality was 100%. The present results stimulate other studies on VOCs for nematode management.

  11. A preliminary survey on soil and plant parasitic nematodes of southern Goa, India

    Directory of Open Access Journals (Sweden)

    A.C.M. Lizanne

    2014-01-01

    Full Text Available A preliminary study was conducted to record the diversity of nematode fauna in Goa during 2011-2012. For the present study 50 samples were collected from five talukas of South Goa District, covering 25 villages and 20 landscapes. Permanent slides were prepared after extraction of nematodes using Cobb’s decanting and sieving method and modified Baermann’s funnel method. The study resulted in recording 52 species of seven orders. Dorylaimida was the dominant order both in number of species and genera while the least was Araeolaimida.

  12. The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant.

    Science.gov (United States)

    Zhang, Li; Lilley, Catherine J; Imren, Mustafa; Knox, J Paul; Urwin, Peter E

    2017-01-01

    Plant-parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida , Heterodera glycines , Heterodera avenae and Heterodera filipjevi , in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines . Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function.

  13. Commercial Biological Control Agents Targeted Against Plant-Parasitic Root-knot Nematodes

    Directory of Open Access Journals (Sweden)

    Marie-Stéphane Tranier

    2014-12-01

    Full Text Available Root-knot nematodes are microscopic round worms, which cause severe agricultural losses. Their attacks affect the productivity by reducing the amount and the caliber of the fruits. Chemical control is widely used, but biological control appears to be a better solution, mainly using microorganisms to reduce the quantity of pests infecting crops. Biological control is developing gradually, and with time, more products are being marketed worldwide. They can be formulated with bacteria, viruses or with filamentous fungi, which can destroy and feed on phytoparasitic nematodes. To be used by the farmers, biopesticides must be legalized by the states, which has led to the establishment of a legal framework for their use, devised by various governmental organizations.

  14. Assessment of weeds as alternative hosts of plant-parasitic nematodes in coffee plantations in Costa Rica

    Directory of Open Access Journals (Sweden)

    Walter Peraza-Padilla

    2018-01-01

    Full Text Available There is potential for weeds to be alternative hosts of plant-parasitic nematodes (PPN, but a methodology that assesses the phytosanitary risk derived from the presence of weeds in plantations is not available. This research was conducted in order to determine if the presence of weeds in coffee plantations (organic and conventional represented a phytosanitary risk due to their role as alternative hosts of PPN. The research was developed into two plantation located in Aserrí, San José, Costa Rica during August, 2010. The most important weeds were identified in the plantations, also nematodes of the genera Meloidogyne, Pratylenchus and Helicotylenchus were quantified in soil and roots from selected weeds and coffee plants. A permutational analysis of variance was executed in order to determine the genera of PPN that significantly differed from the ones found in weeds to the ones found in coffee plants. Based on these results, the weeds were classified as: reservoir, trap crop, or weak host of PPN. This classification criterion, in addition to life cycle and type of parasitism of the PPN were used to assign numerical values to the weeds. The values were used to calculate the Phytosanitary Risk Index (PRI that acquired a maximum value of 10 for the weed Piper umbellatum in the organic plantation, and a maximum value of 24 for Commelina diffusa, Emilia fosbergii, Spananthe paniculata, Delilia biflora, and Spermacoce hirta in the conventional plantation. The results indicated that from a nematological perspective the presence of these weeds in coffee plantation could be a potential risk for coffee plants

  15. Arbuscular mycorrhizal fungi for the biocontrol of plant-parasitic nematodes: a review of the mechanisms involved

    Directory of Open Access Journals (Sweden)

    Nele eSchouteden

    2015-11-01

    Full Text Available Arbuscular mycorrhizal fungi (AMF are obligate root symbionts that can protect their host plant against biotic stress factors such as plant parasitic nematode (PPN infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead towards future field applications of AMF against PPN. The scientific community has entered an exciting era that provide the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead.

  16. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved.

    Science.gov (United States)

    Schouteden, Nele; De Waele, Dirk; Panis, Bart; Vos, Christine M

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts that can protect their host plant against biotic stress factors such as plant-parasitic nematode (PPN) infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR) and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead toward future field applications of AMF against PPN. The scientific community has entered an exciting era that provides the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead.

  17. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved

    Science.gov (United States)

    Schouteden, Nele; De Waele, Dirk; Panis, Bart; Vos, Christine M.

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts that can protect their host plant against biotic stress factors such as plant-parasitic nematode (PPN) infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR) and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead toward future field applications of AMF against PPN. The scientific community has entered an exciting era that provides the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead. PMID:26635750

  18. Hybridization and polyploidy enable genomic plasticity without sex in the most devastating plant-parasitic nematodes.

    Directory of Open Access Journals (Sweden)

    Romain Blanc-Mathieu

    2017-06-01

    Full Text Available Root-knot nematodes (genus Meloidogyne exhibit a diversity of reproductive modes ranging from obligatory sexual to fully asexual reproduction. Intriguingly, the most widespread and devastating species to global agriculture are those that reproduce asexually, without meiosis. To disentangle this surprising parasitic success despite the absence of sex and genetic exchanges, we have sequenced and assembled the genomes of three obligatory ameiotic and asexual Meloidogyne. We have compared them to those of relatives able to perform meiosis and sexual reproduction. We show that the genomes of ameiotic asexual Meloidogyne are large, polyploid and made of duplicated regions with a high within-species average nucleotide divergence of ~8%. Phylogenomic analysis of the genes present in these duplicated regions suggests that they originated from multiple hybridization events and are thus homoeologs. We found that up to 22% of homoeologous gene pairs were under positive selection and these genes covered a wide spectrum of predicted functional categories. To biologically assess functional divergence, we compared expression patterns of homoeologous gene pairs across developmental life stages using an RNAseq approach in the most economically important asexually-reproducing nematode. We showed that >60% of homoeologous gene pairs display diverged expression patterns. These results suggest a substantial functional impact of the genome structure. Contrasting with high within-species nuclear genome divergence, mitochondrial genome divergence between the three ameiotic asexuals was very low, signifying that these putative hybrids share a recent common maternal ancestor. Transposable elements (TE cover a ~1.7 times higher proportion of the genomes of the ameiotic asexual Meloidogyne compared to the sexual relative and might also participate in their plasticity. The intriguing parasitic success of asexually-reproducing Meloidogyne species could be partly explained by

  19. Exploitation of FTA cartridges for the sampling, long-term storage, and DNA-based analyses of plant-parasitic nematodes.

    Science.gov (United States)

    Marek, Martin; Zouhar, Miloslav; Douda, Ondřej; Maňasová, Marie; Ryšánek, Pavel

    2014-03-01

    The use of DNA-based analyses in molecular plant nematology research has dramatically increased over recent decades. Therefore, the development and adaptation of simple, robust, and cost-effective DNA purification procedures are required to address these contemporary challenges. The solid-phase-based approach developed by Flinders Technology Associates (FTA) has been shown to be a powerful technology for the preparation of DNA from different biological materials, including blood, saliva, plant tissues, and various human and plant microbial pathogens. In this work, we demonstrate, for the first time, that this FTA-based technology is a valuable, low-cost, and time-saving approach for the sampling, long-term archiving, and molecular analysis of plant-parasitic nematodes. Despite the complex structure and anatomical organization of the multicellular bodies of nematodes, we report the successful and reliable DNA-based analysis of nematode high-copy and low-copy genes using the FTA technology. This was achieved by applying nematodes to the FTA cards either in the form of a suspension of individuals, as intact or pestle-crushed nematodes, or by the direct mechanical printing of nematode-infested plant tissues. We further demonstrate that the FTA method is also suitable for the so-called "one-nematode-assay", in which the target DNA is typically analyzed from a single individual nematode. More surprisingly, a time-course experiment showed that nematode DNA can be detected specifically in the FTA-captured samples many years after initial sampling occurs. Collectively, our data clearly demonstrate the applicability and the robustness of this FTA-based approach for molecular research and diagnostics concerning phytonematodes; this research includes economically important species such as the stem nematode (Ditylenchus dipsaci), the sugar beet nematode (Heterodera schachtii), and the Northern root-knot nematode (Meloidogyne hapla).

  20. Conjoint effect of oil-seed cakes and Pseudomonas fluorescens on the growth of chickpea in relation to the management of plant-parasitic nematodes

    Directory of Open Access Journals (Sweden)

    Rose Rizvi

    2012-12-01

    Full Text Available Soil application of organics has been explored as an alternative means of organic management of plant-parasitic nematodes. Efficiency of different oil-seed cakes of neem (Azadirachta indica, castor (Ricinus communis, groundnut (Arachis hypogaea, linseed (Linum usitatissimum, sunflower (Helianthus annuus and soybean (Glycine max were evaluated in field conditions with association of Pseudomonas fluorescens in relation to growth parameters of chickpea and population of plant-parasitic nematodes. Their efficacious nature was highly effective in reducing the population of these dominant soil nematodes. Significant improvement was observed in plant-growth parameters such as plant weight, percent pollen fertility, pod numbers, root-nodulation and chlorophyll content of chickpea, seemed to be due to reduction in disease incidence and might be due to growth promoting substances secreted by P. fluorescens. The multiplication rate of nematodes was less in the presence of P. fluorescens as compared to its absence. Most effective combination of P. fluorescens was observed with neem cake.

  1. Sewage sludge amendment and inoculation with plant-parasitic nematodes do not facilitate the internalization of Salmonella Typhimurium LT2 in lettuce plants.

    Science.gov (United States)

    Fornefeld, Eva; Baklawa, Mohamed; Hallmann, Johannes; Schikora, Adam; Smalla, Kornelia

    2018-05-01

    Contamination of fruits and vegetables with Salmonella is a serious threat to human health. In order to prevent possible contaminations of fresh produce it is necessary to identify the contributing ecological factors. In this study we investigated whether the addition of sewage sludge or the presence of plant-parasitic nematodes foster the internalization of Salmonella enterica serovar Typhimurium LT2 into lettuce plants, posing a potential threat for human health. Greenhouse experiments were conducted to investigate whether the amendment of sewage sludge to soil or the presence of plant-parasitic nematodes Meloidogyne hapla or Pratylenchus crenatus promote the internalization of S. Typhimurium LT2 from soil into the edible part of lettuce plants. Unexpectedly, numbers of cultivable S. Typhimurium LT2 decreased faster in soil with sewage sludge than in control soil but not in root samples. Denaturing gradient gel electrophoresis analysis revealed shifts of the soil bacterial communities in response to sewage sludge amendment and time. Infection and proliferation of nematodes inside plant roots were observed but did not influence the number of cultivable S. Typhimurium LT2 in the root samples or in soil. S. Typhimurium LT2 was not detected in the leaf samples 21 and 49 days after inoculation. The results indicate that addition of sewage sludge, M. hapla or P. crenatus to soil inoculated with S. Typhimurium LT2 did not result in an improved survival in soil or internalization of lettuce plants. Copyright © 2017. Published by Elsevier Ltd.

  2. Endogenous cellulases in animals: Isolation of β-1,4-endoglucanase genes from two species of plant-parasitic cyst nematodes

    Science.gov (United States)

    Smant, Geert; Stokkermans, Jack P. W. G.; Yan, Yitang; de Boer, Jan M.; Baum, Thomas J.; Wang, Xiaohong; Hussey, Richard S.; Gommers, Fred J.; Henrissat, Bernard; Davis, Eric L.; Helder, Johannes; Schots, Arjen; Bakker, Jaap

    1998-01-01

    β-1,4-Endoglucanases (EGases, EC 3.2.1.4) degrade polysaccharides possessing β-1,4-glucan backbones such as cellulose and xyloglucan and have been found among extremely variegated taxonomic groups. Although many animal species depend on cellulose as their main energy source, most omnivores and herbivores are unable to produce EGases endogenously. So far, all previously identified EGase genes involved in the digestive system of animals originate from symbiotic microorganisms. Here we report on the synthesis of EGases in the esophageal glands of the cyst nematodes Globodera rostochiensis and Heterodera glycines. From each of the nematode species, two cDNAs were characterized and hydrophobic cluster analysis revealed that the four catalytic domains belong to family 5 of the glycosyl hydrolases (EC 3.2.1, 3.2.2, and 3.2.3). These domains show 37–44% overall amino acid identity with EGases from the bacteria Erwinia chrysanthemi, Clostridium acetobutylicum, and Bacillus subtilis. One EGase with a bacterial type of cellulose-binding domain was identified for each nematode species. The leucine-rich hydrophobic core of the signal peptide and the presence of a polyadenylated 3′ end precluded the EGases from being of bacterial origin. Cyst nematodes are obligatory plant parasites and the identified EGases presumably facilitate the intracellular migration through plant roots by partial cell wall degradation. PMID:9560201

  3. The utility of mtDNA and rDNA for barcoding and phylogeny of plant-parasitic nematodes from Longidoridae (Nematoda, Enoplea).

    Science.gov (United States)

    Palomares-Rius, J E; Cantalapiedra-Navarrete, C; Archidona-Yuste, A; Subbotin, S A; Castillo, P

    2017-09-07

    The traditional identification of plant-parasitic nematode species by morphology and morphometric studies is very difficult because of high morphological variability that can lead to considerable overlap of many characteristics and their ambiguous interpretation. For this reason, it is essential to implement approaches to ensure accurate species identification. DNA barcoding aids in identification and advances species discovery. This study sought to unravel the use of the mitochondrial marker cytochrome c oxidase subunit 1 (coxI) as barcode for Longidoridae species identification, and as a phylogenetic marker. The results showed that mitochondrial and ribosomal markers could be used as barcoding markers, except for some species from the Xiphinema americanum group. The ITS1 region showed a promising role in barcoding for species identification because of the clear molecular variability among species. Some species presented important molecular variability in coxI. The analysis of the newly provided sequences and the sequences deposited in GenBank showed plausible misidentifications, and the use of voucher species and topotype specimens is a priority for this group of nematodes. The use of coxI and D2 and D3 expansion segments of the 28S rRNA gene did not clarify the phylogeny at the genus level.

  4. Identification of plant parasitic nematodes in guava (Psidium guajava L.), at the municipality of Manizales (Caldas), Colombia

    International Nuclear Information System (INIS)

    Guzman Piedrahita, Oscar Adrian; Castano Zapata, Jairo

    2010-01-01

    The future of the colombian fruticulture is in permanent crops, such as tropical fruits, amongst them guava. This research had as objective to identify the parasitic nematodes of this crop. The study was conducted at the region of La Cabana, municipality of Manizales, Caldas, located at 1.100 most, average annual temperature of 24 Celsius degrade and annual precipitation of 2.100 mm. The sampling was carried out in a plantation of guava Pera of 3 years old. At random were sampled 10 trees, and from each one was obtained samples of 100 g of roots and 500 g of soil. The extraction of nematodes was done by following the method of centrifugation and sugar flotation. It was identified: Meloidogyne, Helicotylenchus and Pratylenchus, being the most important the root-knob nematode Meloidogyne spp.

  5. The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant

    Directory of Open Access Journals (Sweden)

    Li Zhang

    2017-06-01

    Full Text Available Plant–parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida, Heterodera glycines, Heterodera avenae and Heterodera filipjevi, in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines. Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function.

  6. A new class of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in plant parasitic cyst nematodes.

    Science.gov (United States)

    Tytgat, Tom; Vanholme, Bartel; De Meutter, Jan; Claeys, Myriam; Couvreur, Marjolein; Vanhoutte, Isabelle; Gheysen, Greetje; Van Criekinge, Wim; Borgonie, Gaetan; Coomans, August; Gheysen, Godelieve

    2004-08-01

    By performing cDNA AFLP on pre- and early parasitic juveniles, we identified genes encoding a novel type of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in the cyst nematode Heterodera schachtii. The proteins consist of three domains, a signal peptide for secretion, a mono-ubiquitin domain, and a short C-terminal positively charged domain. A gfp-fusion of this protein is targeted to the nucleolus in tobacco BY-2 cells. We hypothesize that the C-terminal peptide might have a regulatory function during syncytium formation in plant roots.

  7. Soil properties and olive cultivar determine the structure and diversity of plant-parasitic nematode communities infesting olive orchards soils in southern Spain.

    Science.gov (United States)

    Palomares-Rius, Juan E; Castillo, Pablo; Montes-Borrego, Miguel; Navas-Cortés, Juan A; Landa, Blanca B

    2015-01-01

    This work has studied for the first time the structure and diversity of plant-parasitic nematodes (PPNs) infesting olive orchard soils in a wide-region in Spain that included 92 locations. It aims at determining which agronomical or environmental factors associated to the olive orchards are the main drivers of the PPNs community structure and diversity. Classical morphological and morphometric identification methods were used to determine the frequency and densities of PPNs. Thirteen families, 34 genera and 77 species of PPNs were identified. The highest diversity was found in Helicotylenchus genus, with six species previously reported in Spain and with H. oleae being a first report. Neodolichorhynchus microphasmis and Diptenchus sp., Diphtherophora sp., and Discotylenchus sp., usually considered fungal feeders, were also reported for the first time associated to olive rhizosphere. PPNs abundance ranged from 66 to 16,288 individuals/500-cm3 of soil with Helicotylenchus digonicus being the most prevalent species, followed by Filenchus sp., Merlinius brevidens and Xiphinema pachtaicum. Nematode abundance and diversity indexes were influenced by olive cultivar, and orchard and soil management practices; while olive variety and soil texture were the main factors driving PPN community composition. Soil physicochemical properties and climatic characteristics most strongly associated to the PPN community composition included pH, sand content and exchangeable K, and maximum and minimum average temperature of the sampled locations. Our data suggests that there is a high diversity of PPNs associated to olive in Southern Spain that can exert different damage to olive roots depending on the olive variety and their abundance. Further analysis to determine the resistance levels of most common olive varieties to the prevalent PPNs in Spain will help to choose the most appropriate ones for the establishment of new plantations. This choice will take into consideration the specific

  8. Identifying Virulence-Associated Genes Using Transcriptomic and Proteomic Association Analyses of the Plant Parasitic Nematode Bursaphelenchus mucronatus

    Directory of Open Access Journals (Sweden)

    Lifeng Zhou

    2016-09-01

    Full Text Available Bursaphelenchus mucronatus (B. mucronatus isolates that originate from different regions may vary in their virulence, but their virulence-associated genes and proteins are poorly understood. Thus, we conducted an integrated study coupling RNA-Seq and isobaric tags for relative and absolute quantitation (iTRAQ to analyse transcriptomic and proteomic data of highly and weakly virulent B. mucronatus isolates during the pathogenic processes. Approximately 40,000 annotated unigenes and 5000 proteins were gained from the isolates. When we matched all of the proteins with their detected transcripts, a low correlation coefficient of r = 0.138 was found, indicating probable post-transcriptional gene regulation involved in the pathogenic processes. A functional analysis showed that five differentially expressed proteins which were all highly expressed in the highly virulent isolate were involved in the pathogenic processes of nematodes. Peroxiredoxin, fatty acid- and retinol-binding protein, and glutathione peroxidase relate to resistance against plant defence responses, while β-1,4-endoglucanase and expansin are associated with the breakdown of plant cell walls. Thus, the pathogenesis of B. mucronatus depends on its successful survival in host plants. Our work adds to the understanding of B. mucronatus’ pathogenesis, and will aid in controlling B. mucronatus and other pinewood nematode species complexes in the future.

  9. Molecular characterization and species delimiting of plant-parasitic nematodes of the genus Pratylenchus from the penetrans group (Nematoda: Pratylenchidae).

    Science.gov (United States)

    Janssen, Toon; Karssen, Gerrit; Orlando, Valeria; Subbotin, Sergei A; Bert, Wim

    2017-12-01

    Root-lesion nematodes of the genus Pratylenchus are an important pest parasitizing a wide range of vascular plants including several economically important crops. However, morphological diagnosis of the more than 100 species is problematic due to the low number of diagnostic features, high morphological plasticity and incomplete taxonomic descriptions. In order to employ barcoding based diagnostics, a link between morphology and species specific sequences has to be established. In this study, we reconstructed a multi-gene phylogeny of the Penetrans group using nuclear ribosomal and mitochondrial gene sequences. A combination of this phylogenetic framework with molecular species delineation analysis, population genetics, morphometric information and sequences from type location material allowed us to establish the species boundaries within the Penetrans group and as such clarify long-standing controversies about the taxonomic status of P. penetrans, P. fallax and P. convallariae. Our study also reveals a remarkable amount of cryptic biodiversity within the genus Pratylenchus confirming that identification on morphology alone can be inconclusive in this taxonomically confusing genus. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Evolution of plant parasitism in the phylum Nematoda.

    Science.gov (United States)

    Quist, Casper W; Smant, Geert; Helder, Johannes

    2015-01-01

    Within the species-rich and trophically diverse phylum Nematoda, at least four independent major lineages of plant parasites have evolved, and in at least one of these major lineages plant parasitism arose independently multiple times. Ribosomal DNA data, sequence information from nematode-produced, plant cell wall-modifying enzymes, and the morphology and origin of the style(t), a protrusible piercing device used to penetrate the plant cell wall, all suggest that facultative and obligate plant parasites originate from fungivorous ancestors. Data on the nature and diversification of plant cell wall-modifying enzymes point at multiple horizontal gene transfer events from soil bacteria to bacterivorous nematodes resulting in several distinct lineages of fungal or oomycete-feeding nematodes. Ribosomal DNA frameworks with sequence data from more than 2,700 nematode taxa combined with detailed morphological information allow for explicit hypotheses on the origin of agronomically important plant parasites, such as root-knot, cyst, and lesion nematodes.

  11. Entomopathogenic and plant pathogenic nematodes as opposing forces in agriculture.

    Science.gov (United States)

    Kenney, Eric; Eleftherianos, Ioannis

    2016-01-01

    Plant-parasitic nematodes are responsible for substantial damages within the agriculture industry every year, which is a challenge that has thus far gone largely unimpeded. Chemical nematicides have been employed with varying degrees of success, but their implementation can be cumbersome, and furthermore they could potentially be neutralising an otherwise positive effect from the entomopathogenic nematodes that coexist with plant-parasitic nematodes in soil environments and provide protection for plants against insect pests. Recent research has explored the potential of employing entomopathogenic nematodes to protect plants from plant-parasitic nematodes, while providing their standard degree of protection against insects. The interactions involved are highly complex, due to both the three-organism system and the assortment of variables present in a soil environment, but a strong collection of evidence has accumulated regarding the suppressive capacity of certain entomopathogenic nematodes and their mutualistic bacteria, in the context of limiting the infectivity of plant-parasitic nematodes. Specific factors produced by certain entomopathogenic nematode complexes during the process of insect infection appear to have a selectively nematicidal, or at least repellant, effect on plant-parasitic nematodes. Using this information, an opportunity has formed to adapt this relationship to large-scale, field conditions and potentially relieve the agricultural industry of one of its most substantial burdens. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  12. Nematode assemblages in the rhizosphere of spring barley (Hordeum vulgare L.) depended on fertilisation and plant growth phase

    DEFF Research Database (Denmark)

    Madsen, Mette Vestergård

    2004-01-01

    rhizosphere; nitrogen and phosphorus fertilisation; nematode assemblages; plant parasites; barley......rhizosphere; nitrogen and phosphorus fertilisation; nematode assemblages; plant parasites; barley...

  13. An ANNEXIN-like protein from the cereal cyst nematode Heterodera avenae suppresses plant defense.

    Directory of Open Access Journals (Sweden)

    Changlong Chen

    Full Text Available Parasitism genes encoding secreted effector proteins of plant-parasitic nematodes play important roles in facilitating parasitism. An annexin-like gene was isolated from the cereal cyst nematode Heterodera avenae (termed Ha-annexin and had high similarity to annexin 2, which encodes a secreted protein of Globodera pallida. Ha-annexin encodes a predicted 326 amino acid protein containing four conserved annexin domains. Southern blotting revealed that there are at least two homologies in the H. avenae genome. Ha-annexin transcripts were expressed within the subventral gland cells of the pre-parasitic second-stage juveniles by in situ hybridization. Additionally, expression of these transcripts were relatively higher in the parasitic second-stage juveniles by quantitative real-time RT-PCR analysis, coinciding with the time when feeding cell formation is initiated. Knockdown of Ha-annexin by method of barley stripe mosaic virus-based host-induced gene silencing (BSMV-HIGS caused impaired nematode infections at 7 dpi and reduced females at 40 dpi, indicating important roles of the gene in parasitism at least in early stage in vivo. Transiently expression of Ha-ANNEXIN in onion epidermal cells and Nicotiana benthamiana leaf cells showed the whole cell-localization. Using transient expression assays in N. benthamiana, we found that Ha-ANNEXIN could suppress programmed cell death triggered by the pro-apoptotic mouse protein BAX and the induction of marker genes of PAMP-triggered immunity (PTI in N. benthamiana. In addition, Ha-ANNEXIN targeted a point in the mitogen-activated protein kinase (MAPK signaling pathway downstream of two kinases MKK1 and NPK1 in N. benthamiana.

  14. The Role of Plant-Parasitic Nematodes and Soil-Borne Fungi in the Decline of Ammophila-Arenaria (L) Link

    NARCIS (Netherlands)

    De Rooij van der Goes, P.C.E.M.

    1995-01-01

    In coastal foredunes, Ammophila arenaria (L.) Link grows vigorously when it is buried regularly by windblown sand and degenerates at stabilized sites. Nematodes and soil-borne fungi were found to be involved in its decline. In order to establish their role in the disease complex, seedlings of A.

  15. Venom allergen-like proteins in secretions of plant-parasitic nematodes activate and suppress extracellular plant immune receptors

    NARCIS (Netherlands)

    Lozano Torres, J.L.

    2014-01-01

    Parasitic worms threaten human, animal and plant health by infecting people, livestock and crops worldwide. Animals and plants share an anciently evolved innate immune system. Parasites modulate this immune system by secreting proteins to maintain their parasitic lifestyle. This thesis

  16. A first list of plant-parasitic nematodes from the Tsitsikamma National Park, with descriptions of two new species of the subfamily Criconematinae

    Directory of Open Access Journals (Sweden)

    Esther Van den Berg

    1996-08-01

    Full Text Available Plant nematodes recorded during surveys in the Tsitsikamma National Park are listed and two new Criconematinae species are described. Females of Criconemoides silvicola spec. nov. have the first three or four annuli separated from the following annuli by a discontinuity, dorsally and ventrally fused submedian lobes which are connected by a ridge laterally, 106-127 smooth, retrorse annuli with numerous irregularities and three to 11 anastomoses, a sharp-pointed tail with last few annuli extended and a 41-49 Urn-long stylet. Ogma tuberculatum spec. nov. females have 53-59 retrorse, tuberculate annuli with six longitudinal rows of broad tuberculate scales, two lip annuli, first with greater diameter than second and a 84-102 urn-long stylet. Males without stylet, with four lines in each lateral field. Juveniles with 61- 68 retrorse annuli, bearing 12 to 14 longitudinal rows of large, broad, rounded, minutely tuberculate, overlapping scales.

  17. Analysis of putative apoplastic effectors from the nematode, Globodera rostochiensis, and identification of an expansin-like protein that can induce and suppress host defenses.

    Science.gov (United States)

    Ali, Shawkat; Magne, Maxime; Chen, Shiyan; Côté, Olivier; Stare, Barbara Gerič; Obradovic, Natasa; Jamshaid, Lubna; Wang, Xiaohong; Bélair, Guy; Moffett, Peter

    2015-01-01

    The potato cyst nematode, Globodera rostochiensis, is an important pest of potato. Like other pathogens, plant parasitic nematodes are presumed to employ effector proteins, secreted into the apoplast as well as the host cytoplasm, to alter plant cellular functions and successfully infect their hosts. We have generated a library of ORFs encoding putative G. rostochiensis putative apoplastic effectors in vectors for expression in planta. These clones were assessed for morphological and developmental effects on plants as well as their ability to induce or suppress plant defenses. Several CLAVATA3/ESR-like proteins induced developmental phenotypes, whereas predicted cell wall-modifying proteins induced necrosis and chlorosis, consistent with roles in cell fate alteration and tissue invasion, respectively. When directed to the apoplast with a signal peptide, two effectors, an ubiquitin extension protein (GrUBCEP12) and an expansin-like protein (GrEXPB2), suppressed defense responses including NB-LRR signaling induced in the cytoplasm. GrEXPB2 also elicited defense response in species- and sequence-specific manner. Our results are consistent with the scenario whereby potato cyst nematodes secrete effectors that modulate host cell fate and metabolism as well as modifying host cell walls. Furthermore, we show a novel role for an apoplastic expansin-like protein in suppressing intra-cellular defense responses.

  18. Analysis of putative apoplastic effectors from the nematode, Globodera rostochiensis, and identification of an expansin-like protein that can induce and suppress host defenses.

    Directory of Open Access Journals (Sweden)

    Shawkat Ali

    Full Text Available The potato cyst nematode, Globodera rostochiensis, is an important pest of potato. Like other pathogens, plant parasitic nematodes are presumed to employ effector proteins, secreted into the apoplast as well as the host cytoplasm, to alter plant cellular functions and successfully infect their hosts. We have generated a library of ORFs encoding putative G. rostochiensis putative apoplastic effectors in vectors for expression in planta. These clones were assessed for morphological and developmental effects on plants as well as their ability to induce or suppress plant defenses. Several CLAVATA3/ESR-like proteins induced developmental phenotypes, whereas predicted cell wall-modifying proteins induced necrosis and chlorosis, consistent with roles in cell fate alteration and tissue invasion, respectively. When directed to the apoplast with a signal peptide, two effectors, an ubiquitin extension protein (GrUBCEP12 and an expansin-like protein (GrEXPB2, suppressed defense responses including NB-LRR signaling induced in the cytoplasm. GrEXPB2 also elicited defense response in species- and sequence-specific manner. Our results are consistent with the scenario whereby potato cyst nematodes secrete effectors that modulate host cell fate and metabolism as well as modifying host cell walls. Furthermore, we show a novel role for an apoplastic expansin-like protein in suppressing intra-cellular defense responses.

  19. The genome and genetics of a high oxidative stress tolerant Serratia sp. LCN16 isolated from the plant parasitic nematode Bursaphelenchus xylophilus.

    Science.gov (United States)

    Vicente, Claudia S L; Nascimento, Francisco X; Ikuyo, Yoriko; Cock, Peter J A; Mota, Manuel; Hasegawa, Koichi

    2016-04-23

    Pine wilt disease (PWD) is a worldwide threat to pine forests, and is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus. Bacteria are known to be associated with PWN and may have an important role in PWD. Serratia sp. LCN16 is a PWN-associated bacterium, highly resistant to oxidative stress in vitro, and which beneficially contributes to the PWN survival under these conditions. Oxidative stress is generated as a part of the basal defense mechanism used by plants to combat pathogenic invasion. Here, we studied the biology of Serratia sp. LCN16 through genome analyses, and further investigated, using reverse genetics, the role of two genes directly involved in the neutralization of H2O2, namely the H2O2 transcriptional factor oxyR; and the H2O2-targeting enzyme, catalase katA. Serratia sp. LCN16 is phylogenetically most closely related to the phytosphere group of Serratia, which includes S. proteamaculans, S. grimessi and S. liquefaciens. Likewise, Serratia sp. LCN16 shares many features with endophytes (plant-associated bacteria), such as genes coding for plant polymer degrading enzymes, iron uptake/transport, siderophore and phytohormone synthesis, aromatic compound degradation and detoxification enzymes. OxyR and KatA are directly involved in the high tolerance to H2O2 of Serratia sp. LCN16. Under oxidative stress, Serratia sp. LCN16 expresses katA independently of OxyR in contrast with katG which is under positive regulation of OxyR. Serratia sp. LCN16 mutants for oxyR (oxyR::int(614)) and katA (katA::int(808)) were sensitive to H2O2 in relation with wild-type, and both failed to protect the PWN from H2O2-stress exposure. Moreover, both mutants showed different phenotypes in terms of biofilm production and swimming/swarming behaviors. This study provides new insights into the biology of PWN-associated bacteria Serratia sp. LCN16 and its extreme resistance to oxidative stress conditions, encouraging further research on the potential role of this

  20. Phenotypic analysis of apoplastic effectors from the phytopathogenic nematode, Globodera rostochiensis demonstrates that an expansin can induce and suppress host defenses

    Science.gov (United States)

    The potato cyst nematode Globodera rostochiensis (Woll.) is an important pest of potato. Like other biotrophic pathogens, plant parasitic nematodes are presumed to employ effector proteins, secreted into the apoplast as well as the host cytoplasm to successfully infect their hosts. We have identifie...

  1. Phylogency and Evolution of Nematodes

    NARCIS (Netherlands)

    Bert, W.; Karssen, G.; Helder, J.

    2011-01-01

    Many plant-parasitic nematodes including members of the genera Meloidogyne (root-knot nematodes), Heterodera and Globodera (cyst nematodes) and Pratylenchus (lesion nematodes) are studied as they cause major damage to crops such as potato, tomato, soybean and sugar beet. Both for fundamental reasons

  2. Conserving and enhancing biological control of nematodes.

    Science.gov (United States)

    Timper, Patricia

    2014-06-01

    Conservation biological control is the modification of the environment or existing practices to protect and enhance antagonistic organisms to reduce damage from pests. This approach to biological control has received insufficient attention compared with inundative applications of microbial antagonists to control nematodes. This review provides examples of how production practices can enhance or diminish biological control of plant-parasitic nematodes and other soilborne pests. Antagonists of nematodes can be enhanced by providing supplementary food sources such as occurs when organic amendments are applied to soil. However, some organic amendments (e.g., manures and plants containing allelopathic compounds) can also be detrimental to nematode antagonists. Plant species and genotype can strongly influence the outcome of biological control. For instance, the susceptibility of the plant to the nematode can determine the effectiveness of control; good hosts will require greater levels of suppression than poor hosts. Plant genotype can also influence the degree of rhizosphere colonization and antibiotic production by antagonists, as well the expression of induced resistance by plants. Production practices such as crop rotation, fallow periods, tillage, and pesticide applications can directly disrupt populations of antagonistic organisms. These practices can also indirectly affect antagonists by reducing their primary nematode host. One of the challenges of conservation biological control is that practices intended to protect or enhance suppression of nematodes may not be effective in all field sites because they are dependent on indigenous antagonists. Ultimately, indicators will need to be identified, such as the presence of particular antagonists, which can guide decisions on where it is practical to use conservation biological control. Antagonists can also be applied to field sites in conjunction with conservation practices to improve the consistency, efficacy, and

  3. Nematode suppression and growth stimulation in corn plants (Zea mays L.) irrigated with domestic effluent.

    Science.gov (United States)

    Barros, Kenia Kelly; do Nascimento, Clístenes Williams Araújo; Florencio, Lourdinha

    2012-01-01

    Treated wastewater has great potential for agricultural use due to its concentrations of nutrients and organic matter, which are capable of improving soil characteristics. Additionally, effluents can induce suppression of plant diseases caused by soil pathogens. This study evaluates the effect of irrigation with effluent in a UASB reactor on maize (Zea mays L.) development and on suppression of the diseases caused by nematodes of the genus Meloidogyne. Twelve lysimeters of 1 m(3) each were arranged in a completely randomized design, with four treatments and three replicates. The following treatments were used: T1 (W+I), irrigation with water and infestation with nematodes; T2 (W+I+NPK), irrigation with water, infestation with nematodes and fertilization with nitrogen (N), phosphorus (P) and potassium (K); T3 (E+I), irrigation with effluent and infestation with nematodes; and T4 (E+I+P), irrigation with effluent, infestation with nematodes and fertilization with phosphorus. The plants irrigated with the effluent plus the phosphorus fertilizer had better growth and productivity and were more resistant to the disease symptoms caused by the nematodes. The suppression levels may have been due to the higher levels of Zn and NO(3)(-) found in the leaf tissue of the plants irrigated with the effluent and phosphorus fertilizer.

  4. Nematodes

    International Nuclear Information System (INIS)

    Suzuki, Kenshi; Ishii, Naoaki

    1977-01-01

    Utilization of nematodes for a study of radiation biology was considered. Structure, generation, rearing method, and genetic nature of nematodes (Caenorhabditis elegans, Turbatri acetic, etc.) were given an outline. As the advantage of a study using nematodes as materials, shortness of one generation time, simplicity in structure, and smallness of the whole cells, specific regular movement, and heliotaxis to chemical substances and light were mentioned. Effect of x-ray on survival rate of nematodes and effect of ultraviolet on nematodes and their eggs were described. It was suggested that nematodes was useful for studies on aging and radiation biology, and a possibility existed that nematodes would be used in studies of cancer and malformation. (Serizawa, K.)

  5. First report of the spiral nematode Helicotylenchus microlobus infecting soybean in North Dakota

    Science.gov (United States)

    Spiral nematodes (Helicotylenchus spp.) are common plant-parasitic nematodes in fields of many crops. In June 2015, two soil samples were collected from a soybean field in Richland County, ND. Nematodes were extracted from soil using the sugar centrifugal flotation method. Plant-parasitic nematodes ...

  6. Transgenic Strategies for Enhancement of Nematode Resistance in Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-05-01

    Full Text Available Plant parasitic nematodes (PPNs are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.

  7. Suppression of NGB and NAB/ERabp1 in tomato modifies root responses to potato cyst nematode infestation.

    Science.gov (United States)

    Dąbrowska-Bronk, Joanna; Czarny, Magdalena; Wiśniewska, Anita; Fudali, Sylwia; Baranowski, Łukasz; Sobczak, Mirosław; Święcicka, Magdalena; Matuszkiewicz, Mateusz; Brzyżek, Grzegorz; Wroblewski, Tadeusz; Dobosz, Renata; Bartoszewski, Grzegorz; Filipecki, Marcin

    2015-05-01

    Plant-parasitic nematodes cause significant damage to major crops throughout the world. The small number of genes conferring natural plant resistance and the limitations of chemical control require the development of new protective strategies. RNA interference or the inducible over-expression of nematicidal genes provides an environment-friendly approach to this problem. Candidate genes include NGB, which encodes a small GTP-binding protein, and NAB/ERabp1, which encodes an auxin-binding protein, which were identified as being up-regulated in tomato roots in a transcriptome screen of potato cyst nematode (Globodera rostochiensis) feeding sites. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization confirmed the localized up-regulation of these genes in syncytia and surrounding cells following nematode infection. Gene-silencing constructs were introduced into tomato, resulting in a 20%-98% decrease in transcription levels. Nematode infection tests conducted on transgenic plants showed 57%-82% reduction in the number of G. rostochiensis females in vitro and 30%-46% reduction in pot trials. Transmission electron microscopy revealed a deterioration of cytoplasm, and degraded mitochondria and plastids, in syncytia induced in plants with reduced NAB/ERabp1 expression. Cytoplasm in syncytia induced in plants with low NGB expression was strongly electron translucent and contained very few ribosomes; however, mitochondria and plastids remained intact. Functional impairments in syncytial cytoplasm of silenced plants may result from NGB's role in ribosome biogenesis; this was confirmed by localization of yellow fluorescent protein (YFP)-labelled NGB protein in nucleoli and co-repression of NGB in plants with reduced NAB/ERabp1 expression. These results demonstrate that NGB and NAB/ERabp1 play important roles in the development of nematode-induced syncytia. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  8. Effect of Soil Moisture and a Surfactant on Entomopathogenic Nematode Suppression of the Pecan Weevil, Curculio caryae

    Science.gov (United States)

    Shapiro-Ilan, David I.; Cottrell, Ted E.; Brown, Ian; Gardner, Wayne A.; Hubbard, Robert K.; Wood, Bruce W.

    2006-01-01

    Our overall goal was to investigate several aspects of pecan weevil, Curculio caryae, suppression with entomopathogenic nematodes. Specifically, our objectives were to: 1) determine optimum moisture levels for larval suppression, 2) determine suppression of adult C. caryae under field conditions, and 3) measure the effects of a surfactant on nematode efficacy. In the laboratory, virulence of Heterorhabditis megidis (UK211) and Steinernema carpocapsae (All) were tested in a loamy sand at gravimetric water contents of negative 0.01, 0.06, 0.3, 1.0, and 15 bars. Curculio caryae larval survival decreased as moisture levels increased. The nematode effect was most pronounced at –0.06 bars. At –0.01 bars, larval survival was ≤5% regardless of nematode presence, thus indicating that intense irrigation alone might reduce C. caryae populations. Overall, our results indicated no effect of a surfactant (Kinetic) on C. caryae suppression with entomopathogenic nematodes. In a greenhouse test, C. caryae larval survival was lower in all nematode treatments compared with the control, yet survival was lower in S. carpocapsae (Italian) and S. riobrave (7–12) treatments than in S. carpocapsae (Agriotos), S. carpocapsae (Mexican), and S. riobrave (355) treatments (survival was reduced to approximately 20% in the S. riobrave [7–12] treatment). A mixture of S. riobrave strains resulted in intermediate larval survival. In field experiments conducted over two consecutive years, S. riobrave (7–12) applications resulted in no observable control, and, although S. carpocapsae (Italian) provided some suppression, treatment effects were generally only detectable one day after treatment. Nematode strains possessing both high levels of virulence and a greater ability to withstand environmental conditions in the field need to be developed and tested. PMID:19259466

  9. Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors

    Science.gov (United States)

    Lozano-Torres, Jose L.; Wilbers, Ruud H. P.; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C.; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

    2014-01-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

  10. Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

    Science.gov (United States)

    Lozano-Torres, Jose L; Wilbers, Ruud H P; Warmerdam, Sonja; Finkers-Tomczak, Anna; Diaz-Granados, Amalia; van Schaik, Casper C; Helder, Johannes; Bakker, Jaap; Goverse, Aska; Schots, Arjen; Smant, Geert

    2014-12-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes most likely utilize

  11. Apoplastic venom allergen-like proteins of cyst nematodes modulate the activation of basal plant innate immunity by cell surface receptors.

    Directory of Open Access Journals (Sweden)

    Jose L Lozano-Torres

    2014-12-01

    Full Text Available Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of the host. However, the nature and mode of action of most immunomodulatory compounds in nematode secretions are not well understood. Here, we show that venom allergen-like proteins of plant-parasitic nematodes selectively suppress host immunity mediated by surface-localized immune receptors. Venom allergen-like proteins are uniquely conserved in secretions of all animal- and plant-parasitic nematodes studied to date, but their role during the onset of parasitism has thus far remained elusive. Knocking-down the expression of the venom allergen-like protein Gr-VAP1 severely hampered the infectivity of the potato cyst nematode Globodera rostochiensis. By contrast, heterologous expression of Gr-VAP1 and two other venom allergen-like proteins from the beet cyst nematode Heterodera schachtii in plants resulted in the loss of basal immunity to multiple unrelated pathogens. The modulation of basal immunity by ectopic venom allergen-like proteins in Arabidopsis thaliana involved extracellular protease-based host defenses and non-photochemical quenching in chloroplasts. Non-photochemical quenching regulates the initiation of the defense-related programmed cell death, the onset of which was commonly suppressed by venom allergen-like proteins from G. rostochiensis, H. schachtii, and the root-knot nematode Meloidogyne incognita. Surprisingly, these venom allergen-like proteins only affected the programmed cell death mediated by surface-localized immune receptors. Furthermore, the delivery of venom allergen-like proteins into host tissue coincides with the enzymatic breakdown of plant cell walls by migratory nematodes. We, therefore, conclude that parasitic nematodes

  12. Characterization of Soil Suppressiveness to Root-Knot Nematodes in Organic Horticulture in Plastic Greenhouse.

    Science.gov (United States)

    Giné, Ariadna; Carrasquilla, Marc; Martínez-Alonso, Maira; Gaju, Núria; Sorribas, Francisco J

    2016-01-01

    The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55) in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness. Fungal parasites were identified by molecular methods. In parallel, pot tests characterized the level of soil suppressiveness and the fungal species growing from the eggs. In addition, the egg parasitic ability of 10 fungal isolates per site was also assessed. The genetic profiles of fungal and bacterial populations from M10.23 and M10.55 soils were obtained by Denaturing Gradient Gel Electrophoresis (DGGE), and compared with a non-suppressive soil (M10.33). In M10.23, Meloidogyne population in soil decreased progressively throughout the rotation zucchini, tomato, and radish or spinach. The percentage of egg parasitism was 54.7% in zucchini crop, the only one in which eggs were detected. Pochonia chlamydosporia was the only fungal species isolated. In M10.55, nematode densities peaked at the end of the spring-summer crops (tomato, zucchini, and cucumber), but disease severity was lower than expected (0.2-6.3). The percentage of fungal egg parasitism ranged from 3 to 84.5% in these crops. The results in pot tests confirmed the suppressiveness of the M10.23 and M10.55 soils against Meloidogyne. The number of eggs per plant and the reproduction factor of the population were reduced (P < 0.05) in both non-sterilized soils compared to the sterilized ones after one nematode generation. P. chlamydosporia was the only fungus isolated from Meloidogyne eggs. In in vitro tests, P. chlamydosporia isolates were able to parasitize Meloidogyne eggs from 50 to 97% irrespective of the site. DGGE fingerprints revealed a high diversity in the microbial populations analyzed. Furthermore, both bacterial and fungal genetic patterns differentiated suppressive from non-suppressive

  13. Characterization of soil suppressiveness to root-knot nematodes in organic horticulture in plastic greenhouse

    Directory of Open Access Journals (Sweden)

    Ariadna eGiné

    2016-02-01

    Full Text Available The fluctuation of Meloidogyne population density and the percentage of fungal egg parasitism were determined from July 2011 to July 2013 in two commercial organic vegetable production sites (M10.23 and M10.55 in plastic greenhouses, located in northeastern Spain, in order to know the level of soil suppressiveness. Fungal parasites were identified by molecular methods. In parallel, pot tests characterized the level of soil suppressiveness and the fungal species growing from the eggs. In addition, the egg parasitic ability of ten fungal isolates per site was also assessed. The genetic profiles of fungal and bacterial populations from M10.23 and M10.55 soils were obtained by Denaturing Gradient Gel Electrophoresis (DGGE, and compared with a non-suppressive soil (M10.33. In M10.23, Meloidogyne population in soil decreased progressively throughout the rotation zucchini, tomato, and radish or spinach. The percentage of egg parasitism was 54.7% in zucchini crop, the only one in which eggs were detected. Pochonia chlamydosporia was the only fungal species isolated. In M10.55, nematode densities peaked at the end of the spring-summer crops (tomato, zucchini, and cucumber, but disease severity was lower than expected (0.2 to 6.3. The percentage of fungal egg parasitism ranged from 3 to 84.5% in these crops. The results in pot tests confirmed the suppressiveness of the M10.23 and M10.55 soils against Meloidogyne. The number of eggs per plant and the reproduction factor of the population were reduced (P < 0.05 in both non-sterilized soils compared to the sterilized ones after one nematode generation. Pochonia chlamydosporia was the only fungus isolated from Meloidogyne eggs. In in vitro tests, P. chlamydosporia isolates were able to parasitize Meloidogyne eggs from 50 to 97% irrespective of the site. DGGE fingerprints revealed a high diversity in the microbial populations analyzed. Furthermore, both bacterial and fungal genetic patterns differentiated

  14. Can arbuscular mycorrhiza fungi and NPK fertilizer suppress nematodes and improve tuber yield of yam (Dioscorea rotundata ‘cv’ ewuru?

    Directory of Open Access Journals (Sweden)

    Gani Oladejo Kolawole

    2018-04-01

    Full Text Available Poor soil fertility and nematodes limit yam tuber yield and quality. Arbuscular mycorrhizal fungi (AMF and fertilizers may suppress nematodes and improve yam productivity. We evaluated the extent AMF and fertilizer suppressed nematodes and improved yam performance. Tuber weight, mycorrhizal colonization of roots and nematode populations were evaluated with eight treatments; Control (No amendments, 90-50-75, kg N- P2O5-K2O ha-1 (NPK, (AMF (2g/kg soil, nematodes (5000 juvenile/pot, and their combinations. Tuber weight was higher in NPK+AMF and NPK+nematode treatments than AMF+nematode. NPK+AMF improved tuber weight by 17.5% and 32% compared with sole NPK or AMF respectively. Compared with control, nematodes did not reduce tuber weight but, AMF+nematode reduced it by 49.4%. NPK reduced AMF colonization of roots and reduced nematode population on tuber, in roots and soil by 34%, 42.6% and 41% respectively. NPK+AMF treatment was superior to either NPK or AMF in improving tuber yield while NPK was superior to AMF in suppressing nematodes in roots, soil, and tuber.

  15. Screening fusarium resistant rootstocks for plant parasitic nematode resistance

    Science.gov (United States)

    The phase out of methyl bromide has directed research toward alternative methods of managing soil-borne pathogens. A limiting factor in many watermelon producing regions is Fusarium wilt caused by the soil-borne fungi Fusarium oxysporum f.sp. niveum (FON). There is no varietal resistance to FON depl...

  16. occurrence of plant parasitic nematodes and factors that enhance

    African Journals Online (AJOL)

    Administrator

    investment and impacts in developing countries1991-1992. CIMMYT Mexico. CIMMYT (International Maize and Wheat. Improvement Center), 1992. CIMMYT world maize facts and trends: maize research investment and impacts in developing countries1991-1992. CIMMYT Mexico. Coyne, D. L. and Talwana, L. A. H. 2000.

  17. Dinâmica de nemátodes fitoparasitas e sua relação com alguns parâmetros físico-químicos do solo durante o cultivo de beterraba sacarina Population dynamics of plant-parasitic nematodes and their relationships with some soil physico-chemical characteristics during sugarbeet cultivation

    Directory of Open Access Journals (Sweden)

    P. Barbosa

    2007-01-01

    Full Text Available O objectivo do estudo centrou-se na avaliação da dinâmica de nemátodes fito parasitas, e relação com alguns parâmetros físico-químicos, num terreno utilizado para produção de beterraba sacarina, na zona de Coruche. Com o intuito de acompanhar o processo de crescimento da cultura, o estudo foi efectuado de Janeiro a Junho de 2003. Recorreu-se a métodos standard para a amostragem, extracção e observação dos nemátodes. Empregaramse comparações estatísticas (Kruskal-Wallis na análise da distribuição mensal dos fitoparasitas. As relações entre indivíduos e parâmetros físico-químicos do seu habitat foram verificadas por análise de componentes principais (PCA, análise canónica de correspondência (CCA e correlações. Em virtude das acções causadas pelas práticas agrícolas, a comunidade decresceu de Janeiro a Abril, aumentando até Junho com o início do processo de rega. O número de nemátodes do género Meloidogyne foi significativamente superior, secundado por Helicotylenchus e Tylenchus. As correlações entre indivíduos e parâmetros ambientais indicam que, aparte a influência directa do hospedeiro, o cálcio, o potássio, o azoto e a humidade do solo influenciaram a abundância e as relações entre os géneros.The objective of this research was studying population dynamics of plant-parasitic nematodes (PPN and their relationships with some soil physico-chemical characteristics, from 1 plot used for sugarbeet production in Coruche. The study was performed from January to June 2003, following the plant growth cycle. Standard sampling, extraction and observation methods were employed. Statistical comparisons (Kruskal-Wallis were used to analyze nematode monthly distribution. Principal Component Analysis (PCA, Correspondence Canonical Analysis (CCA and correlations were used to correlate PPN numbers and several physical and chemical parameters. As a result of agricultural practices, the community declined from

  18. Microbial ecology and nematode control in natural ecosystems

    NARCIS (Netherlands)

    Costa, S.R.; Van der Putten, W.H.; Kerry, B.R.

    2011-01-01

    Plant-parasitic nematodes have traditionally been studied in agricultural systems, where they can be pests of importance on a wide range of crops. Nevertheless, nematode ecology in natural ecosystems is receiving increasing interest because of the role of nematodes in soil food webs, nutrient

  19. Nematode CLE signaling in Arabidopsis requires CLAVATA2 and CORYNE

    Science.gov (United States)

    Plant-parasitic cyst nematodes secrete CLAVATA3 (CLV3)/ESR(CLE)-like effector proteins. These proteins have been shown to act as ligand mimics of plant CLE peptides and are required for successful nematode infection; however, the receptors for nematode CLE-like peptides have not been identified. Her...

  20. Bacterial microbiome and nematode occurrence in different potato agricultural soils

    Science.gov (United States)

    Pratylenchus neglectus and Meloidogyne chitwoodi are the main plant-parasitic nematodes in potato crops of the San Luis Valley, Colorado. Bacterial microbiome (16S rRNA copies per gram of soil) and nematode communities (nematodes per 200 gr of soil) from five different potato farms were analyzed to ...

  1. A Novel Meloidogyne incognita Effector Misp12 Suppresses Plant Defense Response at Latter Stages of Nematode Parasitism

    Science.gov (United States)

    Xie, Jialian; Li, Shaojun; Mo, Chenmi; Wang, Gaofeng; Xiao, Xueqiong; Xiao, Yannong

    2016-01-01

    Secreted effectors in plant root-knot nematodes (RKNs, or Meloidogyne spp.) play key roles in their parasite processes. Currently identified effectors mainly focus on the early stage of the nematode parasitism. There are only a few reports describing effectors that function in the latter stage. In this study, we identified a potential RKN effector gene, Misp12, that functioned during the latter stage of parasitism. Misp12 was unique in the Meloidogyne spp., and highly conserved in Meloidogyne incognita. It encoded a secretory protein that specifically expressed in the dorsal esophageal gland, and highly up-regulated during the female stages. Transient expression of Misp12-GUS-GFP in onion epidermal cell showed that Misp12 was localized in cytoplast. In addition, in planta RNA interference targeting Misp12 suppressed the expression of Misp12 in nematodes and attenuated parasitic ability of M. incognita. Furthermore, up-regulation of jasmonic acid (JA) and salicylic acid (SA) pathway defense-related genes in the virus-induced silencing of Misp12 plants, and down-regulation of SA pathway defense-related genes in Misp12-expressing plants indicated the gene might be associated with the suppression of the plant defense response. These results demonstrated that the novel nematode effector Misp12 played a critical role at latter parasitism of M. incognita. PMID:27446188

  2. Plant parasite control and soil fauna diversity.

    Science.gov (United States)

    Lavelle, Patrick; Blouin, Manuel; Boyer, Johnny; Cadet, Patrice; Laffray, Daniel; Pham-Thi, Anh-Thu; Reversat, Georges; Settle, William; Zuily, Yasmine

    2004-07-01

    The use of pesticides to control plant parasites and diseases has generated serious problems of public health and environmental quality, leading to the promotion of alternative Integrated Pest Management strategies that tend to rely more on natural processes and the active participation of farmers as observers and experimenters in their own fields. We present three case studies that point at different options provided by locally available populations of soil organisms, the maintenance of diverse populations of pests or increased resistance of plants to pest attacks by their interactions with earthworms and other useful soil organisms. These examples demonstrate the diversity of options offered by the non-planned agro-ecosystem diversity in pest control and the need to identify management options that maintain this biodiversity.

  3. Suppression of soil decomposers and promotion of long-lived, root herbivorous nematodes by climate change

    DEFF Research Database (Denmark)

    Stevnbak, Karen; Maraldo, Kristine; Georgieva, Slavka

    2012-01-01

    to climate change predictions for the coming decades. Removing precipitation for two summer months reduced all decomposer organisms assessed, i.e., microbial biomass, protozoa, bacteri- and fungivorous nematodes and enchytraeids, probably with negative effects on soil decomposition. Increasing temperature...... by about 1 °C reduced all nematodes including the dominant trophic group, the root herbivores, by almost 50% in the upper layer. The remaining assemblage of root herbivorous nematodes, however, shifted towards species with longer generation times, possibly because of an earlier start of plant growth...

  4. Pasteuria spp.: Systematics and Phylogeny of These Bacterial Parasites of Phytopathogenic Nematodes.

    Science.gov (United States)

    Preston, J F; Dickson, D W; Maruniak, J E; Nong, G; Brito, J A; Schmidt, L M; Giblin-Davis, R M

    2003-06-01

    Pasteuria spp. include endospore-forming bacterial pathogens of cladoceran crustaceans and plant-parasitic nematodes. Propagation of these nematode pathogens requires attachment of soilborne endospores to nematode hosts, infection, growth, sporulation, and release of endospores to repeat the cycle of infection and propagation. The ability of these bacteria to suppress the levels of plant-parasitic nematodes in the field has made them particularly promising candidates for biocontrol of nematode diseases of plants. Genes encoding 16S ribosomal RNA have been sequenced for the cladoceran (water flea) parasite and type species, Pasteuria ramosa, and for Pasteuria spp. isolated from root-knot (Meloidogyne arenaria race 1 and Meloidogyne sp.), soybean cyst (Heterodera glycines), and sting (Belonolaimus longicaudatus) nematodes. These have provided a phylogenetic basis for their designation to a distinct clade within the family Alicyclobacillaceae of the gram-positive endospore-forming bacteria. Two apparent biotypes of P. penetrans demonstrating a host preference for different Meloidogyne spp. showed identical 16S rDNA sequences, suggesting host-recognition evolves within a given species. The sequences of genes encoding sporulation transcription factors, sigE and sigF, from P. penetrans biotype P-20 show different phylogenetic relationships to other endospore-forming bacteria, supporting their application to further discriminate Pasteuria spp. and biotypes. Distribution of an adhesin-associated epitope on polypeptides from different Pasteuria isolates provides an immunochemical approach to differentiate species and biotypes with specific host preferences. Application of bioinformatics to genomic data, as well as further characterization of the biochemical basis for host recognition, will facilitate development of Pasteuria spp. as benign alternatives to chemical nematicides.

  5. Genomic characterisation of the effector complement of the potato cyst nematode Globodera pallida.

    Science.gov (United States)

    Thorpe, Peter; Mantelin, Sophie; Cock, Peter Ja; Blok, Vivian C; Coke, Mirela C; Eves-van den Akker, Sebastian; Guzeeva, Elena; Lilley, Catherine J; Smant, Geert; Reid, Adam J; Wright, Kathryn M; Urwin, Peter E; Jones, John T

    2014-10-23

    The potato cyst nematode Globodera pallida has biotrophic interactions with its host. The nematode induces a feeding structure - the syncytium - which it keeps alive for the duration of the life cycle and on which it depends for all nutrients required to develop to the adult stage. Interactions of G. pallida with the host are mediated by effectors, which are produced in two sets of gland cells. These effectors suppress host defences, facilitate migration and induce the formation of the syncytium. The recent completion of the G. pallida genome sequence has allowed us to identify the effector complement from this species. We identify 128 orthologues of effectors from other nematodes as well as 117 novel effector candidates. We have used in situ hybridisation to confirm gland cell expression of a subset of these effectors, demonstrating the validity of our effector identification approach. We have examined the expression profiles of all effector candidates using RNAseq; this analysis shows that the majority of effectors fall into one of three clusters of sequences showing conserved expression characteristics (invasive stage nematode only, parasitic stage only or invasive stage and adult male only). We demonstrate that further diversity in the effector pool is generated by alternative splicing. In addition, we show that effectors target a diverse range of structures in plant cells, including the peroxisome. This is the first identification of effectors from any plant pathogen that target this structure. This is the first genome scale search for effectors, combined to a life-cycle expression analysis, for any plant-parasitic nematode. We show that, like other phylogenetically unrelated plant pathogens, plant parasitic nematodes deploy hundreds of effectors in order to parasitise plants, with different effectors required for different phases of the infection process.

  6. Mechanisms and Characterization of Trichoderma longibrachiatum T6 in Suppressing Nematodes (Heterodera avenae in Wheat

    Directory of Open Access Journals (Sweden)

    Shuwu Zhang

    2017-09-01

    Full Text Available Heterodera avenae is an important soil-borne pathogen that affects field crops worldwide. Chemical nematicides can be used to control the nematode, but they bring toxicity to the environment and human. Trichoderma longibrachiatum has been shown to have the ability to control H. avenae cysts, but detailed microscopic observations and bioassays are lacking. In this study, we used microscopic observations and bioassays to study the effect of T. longibrachiatum T6 (TL6 on the eggs and second stage juveniles (J2s of H. avenae, and investigate the role of TL6 in inducing the resistance to H. avenae in wheat seedling at physiological and biochemical levels. Microscopic observations recorded that TL6 parasitized on the H. avenae eggs, germinated, and produced a large number of hyphae on the eggs surface at the initial stage, thereafter, the eggs were completely surrounded by dense mycelia and the contents of eggs were lysed at the late stage. Meanwhile, the conidia suspension of TL6 parasitized on the surface of J2s, produced a large number of hyphae that penetrated the cuticle and caused deformation of the nematodes. TL6 at the concentration of 1.5 × 107 conidia ml−1 had the highest rates of parasitism on eggs and J2s, reflected by the highest hatching-inhibition of eggs and the mortality of J2s. In the greenhouse experiments, wheat seedlings treated with TL6 at 1.5 × 107 conidia ml−1 had reduced H. avenae infection, and increased plant growth significantly compared to the control. The cysts and juveniles in soil were reduced by 89.8 and 92.7%, the juveniles and females in roots were reduced by 88.3 and 91.3%, whereas the activity of chitinase and β-1, 3-glucanase, total flavonoids and lignin contents in wheat roots were increased significantly at different stage after inoculation with the eggs and TL6 conidia in comparison to the control. Maximum activity of chitinase and β-1, 3-glucanase were recorded at the 20th and 15th Days after

  7. Effect of winter cover crops on nematode population levels in north Florida.

    Science.gov (United States)

    Wang, K-H; McSorley, R; Gallaher, R N

    2004-12-01

    Two experiments were conducted in north-central Florida to examine the effects of various winter cover crops on plant-parasitic nematode populations through time. In the first experiment, six winter cover crops were rotated with summer corn (Zea mays), arranged in a randomized complete block design. The cover crops evaluated were wheat (Triticum aestivum), rye (Secale cereale), oat (Avena sativa), lupine (Lupinus angustifolius), hairy vetch (Vicia villosa), and crimson clover (Trifolium incarnatum). At the end of the corn crop in year 1, population densities of Meloidogyne incognita were lowest on corn following rye or oat (P rye or lupine was planted into field plots with histories of five tropical cover crops: soybean (Glycine max), cowpea (Vigna unguiculata), sorghum-sudangrass (Sorghum bicolor x S. sudanense), sunn hemp (Crotalaria juncea), and corn. Population densities of M. incognita and Helicotylenchus dihystera were affected by previous tropical cover crops (P cover crops present at the time of sampling. Plots planted to sunn hemp in the fall maintained the lowest M. incognita and H. dihystera numbers. Results suggest that winter cover crops tested did not suppress plant-parasitic nematodes effectively. Planting tropical cover crops such as sunn hemp after corn in a triple-cropping system with winter cover crops may provide more versatile nematode management strategies in northern Florida.

  8. Regulatory interplay between soybean root and soybean cyst nematode during a resistant and susceptible reaction

    Science.gov (United States)

    Background: Plant parasitic nematodes (PPNs) are obligate parasites that feed on the roots of living host plants. Often, these nematodes can lay hundreds of eggs, each capable of surviving in the soil for as long as 12 years. When it comes to wreaking havoc on agricultural yield, few nematodes can c...

  9. Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis

    NARCIS (Netherlands)

    Jones, J.T.; Reavy, B.; Smant, G.; Prior, A.E.

    2004-01-01

    We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for

  10. Book review: Systematics of Cyst Nematodes (Nematoda: Heteroderinae)

    Science.gov (United States)

    The cyst nematodes are an important group of plant-parasitic nematodes that cause billions of dollars in economic damage to crops every year. This article reviews a recently published, two-volume monograph that describes the morphological and molecular characteristics of these agriculturally signif...

  11. Disruption of prefoldin-2 protein synthesis in root-knot nematodes via host-mediated gene silencing efficiently reduces nematode numbers and thus protects plants.

    Science.gov (United States)

    Ajjappala, Hemavathi; Chung, Ha Young; Sim, Joon-Soo; Choi, Inchan; Hahn, Bum-Soo

    2015-03-01

    The aim of this study is to demonstrate the feasibility of down-regulating endogeneous prefoldin-2 root-knot nematode transcripts by expressing dsRNA with sequence identity to the nematode gene in tobacco roots under the influence of strong Arabidopsis ubiquitin (UBQ1) promoter. Root-knot nematodes (RKNs) are sedentary endoparasites infecting a wide range of plant species. They parasitise the root system, thereby disrupting water and nutrient uptake and causing major reductions in crop yields. The most reliable means of controlling RKNs is via the use of soil fumigants such as methyl bromide. With the emergence of RNA interference (RNAi) technology, which permits host-mediated nematode gene silencing, a new strategy to control plant pathogens has become available. In the present study, we investigated host-induced RNAi gene silencing of prefoldin-2 in transgenic Nicotiana benthamiana. Reductions in prefoldin-2 mRNA transcript levels were observed when nematodes were soaked in a dsRNA solution in vitro. Furthermore, nematode reproduction was suppressed in RNAi transgenic lines, as evident by reductions in the numbers of root knots (by 34-60 % in independent RNAi lines) and egg masses (by 33-58 %). Endogenous expression of prefoldin-2, analysed via real-time polymerase chain reaction and Western blotting, revealed that the gene was strongly expressed in the pre-parasitic J2 stage. Our observations demonstrate the relevance and potential importance of targeting the prefoldin gene during the nematode life cycle. The work also suggests that further improvements in silencing efficiency in economically important crops can be accomplished using RNAi directed against plant-parasitic nematodes.

  12. Functional analysis of pathogenicity proteins of the potato cyst nematode Globodera rostochiensis using RNAi.

    Science.gov (United States)

    Chen, Qing; Rehman, S; Smant, G; Jones, John T

    2005-07-01

    RNA interference (RNAi) has been used widely as a tool for examining gene function and a method that allows its use with plant-parasitic nematodes recently has been described. Here, we use a modified method to analyze the function of secreted beta-1,4, endoglucanases of the potato cyst nematode Globodera rostochiensis, the first in vivo functional analysis of a pathogenicity protein of a plant-parasitic nematode. Knockout of the beta-1,4, endoglucanases reduced the ability of the nematodes to invade roots. We also use RNAi to show that gr-ams-1, a secreted protein of the main sense organs (the amphids), is essential for host location.

  13. A SNARE-Like Protein and Biotin Are Implicated in Soybean Cyst Nematode Virulence.

    Directory of Open Access Journals (Sweden)

    Sadia Bekal

    Full Text Available Phytoparasitic nematodes that are able to infect and reproduce on plants that are considered resistant are referred to as virulent. The mechanism(s that virulent nematodes employ to evade or suppress host plant defenses are not well understood. Here we report the use of a genetic strategy (allelic imbalance analysis to associate single nucleotide polymorphisms (SNPs with nematode virulence genes in Heterodera glycines, the soybean cyst nematode (SCN. To accomplish this analysis, a custom SCN SNP array was developed and used to genotype SCN F3-derived populations grown on resistant and susceptible soybean plants. Three SNPs reproducibly showed allele imbalances between nematodes grown on resistant and susceptible plants. Two candidate SCN virulence genes that were tightly linked to the SNPs were identified. One SCN gene encoded biotin synthase (HgBioB, and the other encoded a bacterial-like protein containing a putative SNARE domain (HgSLP-1. The two genes mapped to two different linkage groups. HgBioB contained sequence polymorphisms between avirulent and virulent nematodes. However, the gene encoding HgSLP-1 had reduced copy number in virulent nematode populations and appears to produce multiple forms of the protein via intron retention and alternative splicing. We show that HgSLP-1 is an esophageal-gland protein that is secreted by the nematode during plant parasitism. Furthermore, in bacterial co-expression experiments, HgSLP-1 co-purified with the SCN resistance protein Rhg1 α-SNAP, suggesting that these two proteins physically interact. Collectively our data suggest that multiple SCN genes are involved in SCN virulence, and that HgSLP-1 may function as an avirulence protein and when absent it helps SCN evade host defenses.

  14. Root-lesion nematodes suppress cabbage aphid population development by reducing aphid daily reproduction

    Directory of Open Access Journals (Sweden)

    W. H. Gera eHol

    2016-02-01

    Full Text Available Empirical studies have shown that belowground feeding herbivores can affect the performance of aboveground herbivores in different ways. Often the critical life-history parameters underlying the observed performance effects remain unexplored. In order to better understand the cause for the observed effects on aboveground herbivores, these ecological mechanisms must be better understood. In this study we combined empirical experiments with a modelling approach to analyse the effect of two root feeding endoparasitic nematodes with different feeding strategies on the population growth of the aboveground feeding specialist aphid Brevicoryne brassicae on Brassica nigra. The aim was to test whether emerging differences in life history characteristics (days until reproduction, daily reproduction would be sufficient to explain observed differences in aphid population development on plants with and without two species of nematodes. Aphid numbers were lower on plants with Pratylenchus penetrans in comparison to aphid numbers on plants with Meloidogyne spp. A dedicated experiment showed that aphid daily reproduction was lower on plants with P. penetrans (3.08 offspring per female per day in comparison to both uninfested plants and plants with Meloidogyne spp. (3.50 offspring per female per day. The species-specific reduction of aphid reproduction appeared independent of changes in amino acids, soluble sugars or the glucosinolate sinigrin in the phloem. An individual-based model revealed that relatively small differences in reproduction rate per female were sufficient to yield a similar difference in aphid populations as was found in the empirical experiments.

  15. Eosinophils are required to suppress Th2 responses in Peyer's patches during intestinal infection by nematodes.

    Science.gov (United States)

    Strandmark, J; Steinfelder, S; Berek, C; Kühl, A A; Rausch, S; Hartmann, S

    2017-05-01

    Infections with enteric nematodes result in systemic type 2 helper T (Th2) responses, expansion of immunoglobulin (Ig)G1 antibodies, and eosinophilia. Eosinophils have a supportive role in mucosal Th2 induction during airway hyperreactivity. Whether eosinophils affect the local T-cell and antibody response in the gut-associated lymphoid tissue during enteric infections is unknown. We infected eosinophil-deficient ΔdblGATA-1 mice with the Th2-inducing small intestinal nematode Heligmosomoides polygyrus and found that parasite fecundity was decreased in the absence of eosinophils. A lack of eosinophils resulted in significantly augmented expression of GATA-3 and IL-4 by CD4 + T cells during acute infection, a finding strictly limited to Peyer's patches (PP). The increase in IL-4-producing cells in ΔdblGATA-1 mice was particularly evident within the CXCR5 + PD-1 + T-follicular helper cell population and was associated with a switch of germinal centre B cells to IgG1 production and elevated serum IgG1 levels. In contrast, infected wild-type mice had a modest IgG1 response in the PP, whereas successfully maintaining a population of IgA + germinal center B cells. Our results suggest a novel role for eosinophils during intestinal infection whereby they restrict IL-4 responses by follicular T helper cells and IgG1 class switching in the PP to ensure maintenance of local IgA production.

  16. Identification and functional analysis of secreted effectors from phytoparasitic nematodes.

    Science.gov (United States)

    Rehman, Sajid; Gupta, Vijai K; Goyal, Aakash K

    2016-03-21

    Plant parasitic nematodes develop an intimate and long-term feeding relationship with their host plants. They induce a multi-nucleate feeding site close to the vascular bundle in the roots of their host plant and remain sessile for the rest of their life. Nematode secretions, produced in the oesophageal glands and secreted through a hollow stylet into the host plant cytoplasm, are believed to play key role in pathogenesis. To combat these persistent pathogens, the identity and functional analysis of secreted effectors can serve as a key to devise durable control measures. In this review, we will recapitulate the knowledge over the identification and functional characterization of secreted nematode effector repertoire from phytoparasitic nematodes. Despite considerable efforts, the identity of genes encoding nematode secreted proteins has long been severely hampered because of their microscopic size, long generation time and obligate biotrophic nature. The methodologies such as bioinformatics, protein structure modeling, in situ hybridization microscopy, and protein-protein interaction have been used to identify and to attribute functions to the effectors. In addition, RNA interference (RNAi) has been instrumental to decipher the role of the genes encoding secreted effectors necessary for parasitism and genes attributed to normal development. Recent comparative and functional genomic approaches have accelerated the identification of effectors from phytoparasitic nematodes and offers opportunities to control these pathogens. Plant parasitic nematodes pose a serious threat to global food security of various economically important crops. There is a wealth of genomic and transcriptomic information available on plant parasitic nematodes and comparative genomics has identified many effectors. Bioengineering crops with dsRNA of phytonematode genes can disrupt the life cycle of parasitic nematodes and therefore holds great promise to develop resistant crops against plant-parasitic

  17. Role of stress-related hormones in plant defence during early infection of the cyst nematode Heterodera schachtii in Arabidopsis

    Science.gov (United States)

    Kammerhofer, Nina; Radakovic, Zoran; Regis, Jully M A; Dobrev, Petre; Vankova, Radomira; Grundler, Florian M W; Siddique, Shahid; Hofmann, Julia; Wieczorek, Krzysztof

    2015-01-01

    Heterodera schachtii, a plant-parasitic cyst nematode, invades host roots and induces a specific syncytial feeding structure, from which it withdraws all required nutrients, causing severe yield losses. The system H. schachtii–Arabidopsis is an excellent research model for investigating plant defence mechanisms. Such responses are suppressed in well-established syncytia, whereas they are induced during early parasitism. However, the mechanisms by which the defence responses are modulated and the role of phytohormones are largely unknown. The aim of this study was to elucidate the role of hormone-based defence responses at the onset of nematode infection. First, concentrations of main phytohormones were quantified and the expression of several hormone-related genes was analysed using quantitative real-time (qRT)-PCR or GeneChip. Further, the effects of individual hormones were evaluated via nematode attraction and infection assays using plants with altered endogenous hormone concentrations. Our results suggest a pivotal and positive role for ethylene during nematode attraction, whereas jasmonic acid triggers early defence responses against H. schachtii. Salicylic acid seems to be a negative regulator during later syncytium and female development. We conclude that nematodes are able to impose specific changes in hormone pools, thus modulating hormone-based defence and signal transduction in strict dependence on their parasitism stage. PMID:25825039

  18. Interspecific nematode signals regulate dispersal behavior.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available Dispersal is an important nematode behavior. Upon crowding or food depletion, the free living bacteriovorus nematode Caenorhabditis elegans produces stress resistant dispersal larvae, called dauer, which are analogous to second stage juveniles (J2 of plant parasitic Meloidogyne spp. and infective juveniles (IJs of entomopathogenic nematodes (EPN, e.g., Steinernema feltiae. Regulation of dispersal behavior has not been thoroughly investigated for C. elegans or any other nematode species. Based on the fact that ascarosides regulate entry in dauer stage as well as multiple behaviors in C. elegans adults including mating, avoidance and aggregation, we hypothesized that ascarosides might also be involved in regulation of dispersal behavior in C. elegans and for other nematodes such as IJ of phylogenetically related EPNs.Liquid chromatography-mass spectrometry analysis of C. elegans dauer conditioned media, which shows strong dispersing activity, revealed four known ascarosides (ascr#2, ascr#3, ascr#8, icas#9. A synthetic blend of these ascarosides at physiologically relevant concentrations dispersed C. elegans dauer in the presence of food and also caused dispersion of IJs of S. feltiae and J2s of plant parasitic Meloidogyne spp. Assay guided fractionation revealed structural analogs as major active components of the S. feltiae (ascr#9 and C. elegans (ascr#2 dispersal blends. Further analysis revealed ascr#9 in all Steinernema spp. and Heterorhabditis spp. infected insect host cadavers.Ascaroside blends represent evolutionarily conserved, fundamentally important communication systems for nematodes from diverse habitats, and thus may provide sustainable means for control of parasitic nematodes.

  19. Impact of no-till cover cropping of Italian ryegrass on above and below ground faunal communities inhabiting a soybean field with special emphasis on soybean cyst nematodes

    Science.gov (United States)

    Two field trials were conducted in Maryland to evaluate the ability of an Italian ryegrass (IR) (Lolium multiflorum) cover crop in a no-till soybean (Glycine max) planting to 1) reduce populations of plant-parasitic nematodes (i.e., the soybean cyst nematode, Heterodera glycines and lesion nematodes...

  20. In planta processing and glycosylation of a nematode CLE effector and its interaction with a CLV2-like receptor to promote parasitism

    Science.gov (United States)

    Like other biotrophic plant pathogens, plant-parasitic nematodes secrete effector proteins into host cells to facilitate infection. Effector proteins that mimic plant CLAVATA3/ESR (CLE)-like proteins have been identified in several cyst nematodes including the potato cyst nematode (PCN); however, th...

  1. Evaluation of tomato genotypes for resistance to root-knot nematodes

    African Journals Online (AJOL)

    Tomato (Solanum lycopersicum) is one of the most popular vegetable crops worldwide, owing to its high nutritive value and diversified use. Tomato production in Ghana is threatened by plant parasitic nematodes, especially the root knot nematodes (Meloidogyne spp.), which are responsible for huge economic yield losses.

  2. The suppression of tomato defence response genes upon potato cyst nematode infection indicates a key regulatory role of miRNAs.

    Science.gov (United States)

    Święcicka, Magdalena; Skowron, Waldemar; Cieszyński, Piotr; Dąbrowska-Bronk, Joanna; Matuszkiewicz, Mateusz; Filipecki, Marcin; Koter, Marek Daniel

    2017-04-01

    Potato cyst nematode Globodera rostochiensis is an obligate parasite of solanaceous plants, triggering metabolic and morphological changes in roots which may result in substantial crop yield losses. Previously, we used the cDNA-AFLP to study the transcriptional dynamics in nematode infected tomato roots. Now, we present the rescreening of already published, upregulated transcript-derived fragment dataset using the most current tomato transcriptome sequences. Our reanalysis allowed to add 54 novel genes to 135, already found as upregulated in tomato roots upon G. rostochiensis infection (in total - 189). We also created completely new catalogue of downregulated sequences leading to the discovery of 76 novel genes. Functional classification of candidates showed that the 'wound, stress and defence response' category was enriched in the downregulated genes. We confirmed the transcriptional dynamics of six genes by qRT-PCR. To place our results in a broader context, we compared the tomato data with Arabidopsis thaliana, revealing similar proportions of upregulated and downregulated genes as well as similar enrichment of defence related transcripts in the downregulated group. Since transcript suppression is quite common in plant-nematode interactions, we assessed the possibility of miRNA-mediated inverse correlation on several tomato sequences belonging to NB-LRR and receptor-like kinase families. The qRT-PCR of miRNAs and putative target transcripts showed an opposite expression pattern in 9 cases. These results together with in silico analyses of potential miRNA targeting to the full repertoire of tomato R-genes show that miRNA mediated gene suppression may be a key regulatory mechanism during nematode parasitism. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Synergistic interaction of CLAVATA1, CLAVATA2, and RECEPTOR-LIKE PROTEIN KINASE 2 in cyst nematode parasitism of Arabidopsis

    Science.gov (United States)

    Plant-parasitic cyst nematodes secrete CLAVATA3 (CLV3)/ENDOSPERM SURROUNDING REGION (ESR) (CLE)-like effector proteins. These proteins act as ligand mimics of plant CLE peptides and are required for successful nematode infection. Previously, we showed that CLV2 and CORYNE (CRN), a heterodimer recept...

  4. Parasitic nematode interactions with mammals and plants.

    Science.gov (United States)

    Jasmer, Douglas P; Goverse, Aska; Smant, Geert

    2003-01-01

    Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.

  5. Connection between the decline of spruce and occurrence of animal pests, especially nematodes

    Energy Technology Data Exchange (ETDEWEB)

    Timans, U.

    1986-12-01

    In various regions of Bavaria, affected by the decline of spruce, attack by insects and especially nematodes was examined on diseased and healthy spruces. A connection between harmful forest insects and the decline of spruce did not become evident, neither over wide areas nor by examination of single trees. Attack by nematodes was examined in soil and wood samples and also in fine feeder roots of diseased and healthy trees. Plant-parasitic nematodes were not found in the wood and in feeder roots. Although root-parasitic nematodes were present in soil samples, their density was too little to account for a direct damage to spruce. They occurred likewise in samples from healthy and diseased trees. Plant-parasitic nematodes can thus be excluded as a possible causal agent for the decline of spruce.

  6. A novel Meloidogyne graminicola effector, MgGPP, is secreted into host cells and undergoes glycosylation in concert with proteolysis to suppress plant defenses and promote parasitism.

    Directory of Open Access Journals (Sweden)

    Jiansong Chen

    2017-04-01

    Full Text Available Plant pathogen effectors can recruit the host post-translational machinery to mediate their post-translational modification (PTM and regulate their activity to facilitate parasitism, but few studies have focused on this phenomenon in the field of plant-parasitic nematodes. In this study, we show that the plant-parasitic nematode Meloidogyne graminicola has evolved a novel effector, MgGPP, that is exclusively expressed within the nematode subventral esophageal gland cells and up-regulated in the early parasitic stage of M. graminicola. The effector MgGPP plays a role in nematode parasitism. Transgenic rice lines expressing MgGPP become significantly more susceptible to M. graminicola infection than wild-type control plants, and conversely, in planta, the silencing of MgGPP through RNAi technology substantially increases the resistance of rice to M. graminicola. Significantly, we show that MgGPP is secreted into host plants and targeted to the ER, where the N-glycosylation and C-terminal proteolysis of MgGPP occur. C-terminal proteolysis promotes MgGPP to leave the ER, after which it is transported to the nucleus. In addition, N-glycosylation of MgGPP is required for suppressing the host response. The research data provide an intriguing example of in planta glycosylation in concert with proteolysis of a pathogen effector, which depict a novel mechanism by which parasitic nematodes could subjugate plant immunity and promote parasitism and may present a promising target for developing new strategies against nematode infections.

  7. Soil nematode community under the non-native trees in the Botanic Garden of Petrozavodsk State University

    Directory of Open Access Journals (Sweden)

    Sushchuk Anna

    2016-12-01

    Full Text Available The particularities of soil nematode communities of the rhizosphere of non-native trees were studied in the Botanic Garden of Petrozavodsk State University (Republic of Karelia. Taxonomic diversity, abundance, community structure and ecological indices derived from nematode fauna analysis were used as the evaluation parameters. Nematode fauna included 51 genera, 6 of them were plant parasitic. The dominant eco-trophic group in the nematode community structure of coniferous trees was bacterial feeders; fungal feeders in most cases were observed in the second numbers. The contribution of bacterial feeders was decreased and plant parasites were increased in eco-trophic structure of nematode communities of deciduous trees in compared with coniferous trees. Analysis of ecological indices showed that the state of soil nematode communities reflects complex, structured (stable soil food web in the biocenoses with deciduous trees, and degraded (basal food web – under coniferous trees.

  8. Nematode neuropeptides as transgenic nematicides.

    Directory of Open Access Journals (Sweden)

    Neil D Warnock

    2017-02-01

    Full Text Available Plant parasitic nematodes (PPNs seriously threaten global food security. Conventionally an integrated approach to PPN management has relied heavily on carbamate, organophosphate and fumigant nematicides which are now being withdrawn over environmental health and safety concerns. This progressive withdrawal has left a significant shortcoming in our ability to manage these economically important parasites, and highlights the need for novel and robust control methods. Nematodes can assimilate exogenous peptides through retrograde transport along the chemosensory amphid neurons. Peptides can accumulate within cells of the central nerve ring and can elicit physiological effects when released to interact with receptors on adjoining cells. We have profiled bioactive neuropeptides from the neuropeptide-like protein (NLP family of PPNs as novel nematicides, and have identified numerous discrete NLPs that negatively impact chemosensation, host invasion and stylet thrusting of the root knot nematode Meloidogyne incognita and the potato cyst nematode Globodera pallida. Transgenic secretion of these peptides from the rhizobacterium, Bacillus subtilis, and the terrestrial microalgae Chlamydomonas reinhardtii reduce tomato infection levels by up to 90% when compared with controls. These data pave the way for the exploitation of nematode neuropeptides as a novel class of plant protective nematicide, using novel non-food transgenic delivery systems which could be deployed on farmer-preferred cultivars.

  9. Mechanisms of host seeking by parasitic nematodes.

    Science.gov (United States)

    Gang, Spencer S; Hallem, Elissa A

    2016-07-01

    The phylum Nematoda comprises a diverse group of roundworms that includes parasites of vertebrates, invertebrates, and plants. Human-parasitic nematodes infect more than one billion people worldwide and cause some of the most common neglected tropical diseases, particularly in low-resource countries [1]. Parasitic nematodes of livestock and crops result in billions of dollars in losses each year [1]. Many nematode infections are treatable with low-cost anthelmintic drugs, but repeated infections are common in endemic areas and drug resistance is a growing concern with increasing therapeutic and agricultural administration [1]. Many parasitic nematodes have an environmental infective larval stage that engages in host seeking, a process whereby the infective larvae use sensory cues to search for hosts. Host seeking is a complex behavior that involves multiple sensory modalities, including olfaction, gustation, thermosensation, and humidity sensation. As the initial step of the parasite-host interaction, host seeking could be a powerful target for preventative intervention. However, host-seeking behavior remains poorly understood. Here we review what is currently known about the host-seeking behaviors of different parasitic nematodes, including insect-parasitic nematodes, mammalian-parasitic nematodes, and plant-parasitic nematodes. We also discuss the neural bases of these behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Chitosan Increases Tomato Root Colonization by Pochonia chlamydosporia and Their Combination Reduces Root-Knot Nematode Damage

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    Nuria Escudero

    2017-09-01

    Full Text Available The use of biological control agents could be a non-chemical alternative for management of Meloidogyne spp. [root-knot nematodes (RKN], the most damaging plant-parasitic nematodes for horticultural crops worldwide. Pochonia chlamydosporia is a fungal parasite of RKN eggs that can colonize endophytically roots of several cultivated plant species, but in field applications the fungus shows a low persistence and efficiency in RKN management. The combined use of P. chlamydosporia with an enhancer could help its ability to develop in soil and colonize roots, thereby increasing its efficiency against nematodes. Previous work has shown that chitosan enhances P. chlamydosporia sporulation and production of extracellular enzymes, as well as nematode egg parasitism in laboratory bioassays. This work shows that chitosan at low concentrations (up to 0.1 mg ml-1 do not affect the viability and germination of P. chlamydosporia chlamydospores and improves mycelial growth respect to treatments without chitosan. Tomato plants irrigated with chitosan (same dose limit increased root weight and length after 30 days. Chitosan irrigation increased dry shoot and fresh root weight of tomato plants inoculated with Meloidogyne javanica, root length when they were inoculated with P. chlamydosporia, and dry shoot weight of plants inoculated with both P. chlamydosporia and M. javanica. Chitosan irrigation significantly enhanced root colonization by P. chlamydosporia, but neither nematode infection per plant nor fungal egg parasitism was affected. Tomato plants cultivated in a mid-suppressive (29.3 ± 4.7% RKN egg infection non-sterilized clay loam soil and irrigated with chitosan had enhanced shoot growth, reduced RKN multiplication, and disease severity. Chitosan irrigation in a highly suppressive (73.7 ± 2.6% RKN egg infection sterilized-sandy loam soil reduced RKN multiplication in tomato. However, chitosan did not affect disease severity or plant growth irrespective of

  11. The effect of partial soil sterilization on plant parasitic nematodes and plant growth

    NARCIS (Netherlands)

    Eissa, M.F.M.

    1971-01-01

    Research was carried out on the possible yield increase of crops in The Netherlands by the use of PSS (partial soil sterilization) on the soil, on the basis of published as well as unpublished data and by experimentation with different disinfectants, soils and plants.

    Following review of the

  12. Role of Horizontal Gene Transfer in the Evolution of Plant Parasitism Among Nematodes

    NARCIS (Netherlands)

    Mitreva, M.; Smant, G.; Helder, J.

    2009-01-01

    Horizontal gene transfer (HGT) implies the non-sexual exchange of genetic material between species ¿ in some cases even across kingdoms. Although common among Bacteria and Archaea, HGTs from pro- to eukaryotes and between eukaryotes were thought to be extremely rare. Recent studies on intracellular

  13. Comparative genomics of a plant-parasitic nematode endosymbiont suggest a role in nutritional symbiosis

    Science.gov (United States)

    Bacterial mutualists can increase the biochemical capacity of animals. Highly co-evolved nutritional mutualists do this by synthesizing nutrients missing from the host's diet. Genomics tools have recently advanced the study of these partnerships. Here we examined the endosymbiont Xiphinematobacter (...

  14. Origin, distribution and 3D-modeling of Gr-EXPB1, an expansin from the potato cyst nematode Globodera rostochiensis

    NARCIS (Netherlands)

    Kudla, U.; Qin Ling,; Milac, A.; Kielak, A.; Maissen, C.; Overmars, H.A.; Popeijus, H.E.; Roze, E.H.A.; Petrescu, A.J.; Smant, G.; Bakker, J.; Helder, J.

    2005-01-01

    Southern analysis showed that Gr-EXPB1, a functional expansin from the potato cyst nematode Globodera rostochiensis, is member of a multigene family, and EST data suggest expansins to be present in other plant parasitic nematodes as well. Homology modeling predicted that Gr-EXPB1 domain 1 (D1) has a

  15. Recombination suppression at the dominant Rhg1/Rfs2 locus underlying soybean resistance to the cyst nematode.

    Science.gov (United States)

    Afzal, Ahmed J; Srour, Ali; Saini, Navinder; Hemmati, Naghmeh; El Shemy, Hany A; Lightfoot, David A

    2012-04-01

    Host resistance to "yellow dwarf" or "moonlight" disease cause by any population (Hg type) of Heterodera glycines I., the soybean cyst nematode (SCN), requires a functional allele at rhg1. The host resistance encoded appears to mimic an apoptotic response in the giant cells formed at the nematode feeding site about 24-48 h after nematode feeding commences. Little is known about how the host response to infection is mediated but a linked set of 3 genes has been identified within the rhg1 locus. This study aimed to identify the role of the genes within the locus that includes a receptor-like kinase (RLK), a laccase and an ion antiporter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles, gene-based markers, and a new Hg type 0 and new recombination events. A syntenic gene cluster on Lg B1 was found. The effectiveness of SNP probes from the RLK for distinguishing homolog sequence variants on LgB1 from alleles at the rhg1 locus on LgG was shown. The resistant allele of the rhg1 locus was shown to be dominant in NILs. None of the recombination events were within the cluster of the three candidate genes. Finally, rhg1 was shown to reduce the plant root development. A model for rhg1 as a dominant multi-gene resistance locus based on the developmental control was inferred.

  16. Arbuscular mycorrhizal fungi affect both penetration and further life stage development of root-knot nematodes in tomato.

    Science.gov (United States)

    Vos, Christine; Geerinckx, Katleen; Mkandawire, Rachel; Panis, Bart; De Waele, Dirk; Elsen, Annemie

    2012-02-01

    The root-knot nematode Meloidogyne incognita poses a worldwide threat to agriculture, with an increasing demand for alternative control options since most common nematicides are being withdrawn due to environmental concerns. The biocontrol potential of arbuscular mycorrhizal fungi (AMF) against plant-parasitic nematodes has been demonstrated, but the modes of action remain to be unraveled. In this study, M. incognita penetration of second-stage juveniles at 4, 8 and 12 days after inoculation was compared in tomato roots (Solanum lycopersicum cv. Marmande) pre-colonized or not by the AMF Glomus mosseae. Further life stage development of the juveniles was also observed in both control and mycorrhizal roots at 12 days, 3 weeks and 4 weeks after inoculation by means of acid fuchsin staining. Penetration was significantly lower in mycorrhizal roots, with a reduction up to 32%. Significantly lower numbers of third- and fourth-stage juveniles and females accumulated in mycorrhizal roots, at a slower rate than in control roots. The results show for the first time that G. mosseae continuously suppresses root-knot nematodes throughout their entire early infection phase of root penetration and subsequent life stage development.

  17. The importance, biology and management of cereal cyst nematodes (Heterodera spp.

    Directory of Open Access Journals (Sweden)

    F. Mokrini

    2018-01-01

    Full Text Available Cereals are exposed to biotic and abiotic stresses. Among the biotic stresses, plant-parasitic nematodes play an important role in decreasing crop yield. Cereal cyst nematodes (CCNs are known to be a major constraint to wheat production in several parts of the world. Significant economic losses due to CCNs have been reported. Recognition and identification of CCNs are the first steps in nematode management. This paper reviews the current distribution of CCNs in different parts of the world and the recent advances in nematode identification. The different approaches for managing CCNs are also discussed.

  18. Host-microbe and microbe-microbe interactions in the evolution of obligate plant parasitism.

    Science.gov (United States)

    Kemen, Ariane C; Agler, Matthew T; Kemen, Eric

    2015-06-01

    Research on obligate biotrophic plant parasites, which reproduce only on living hosts, has revealed a broad diversity of filamentous microbes that have independently acquired complex morphological structures, such as haustoria. Genome studies have also demonstrated a concerted loss of genes for metabolism and lytic enzymes, and gain of diversity of genes coding for effectors involved in host defense suppression. So far, these traits converge in all known obligate biotrophic parasites, but unexpected genome plasticity remains. This plasticity is manifested as transposable element (TE)-driven increases in genome size, observed to be associated with the diversification of virulence genes under selection pressure. Genome expansion could result from the governing of the pathogen response to ecological selection pressures, such as host or nutrient availability, or to microbial interactions, such as competition, hyperparasitism and beneficial cooperations. Expansion is balanced by alternating sexual and asexual cycles, as well as selfing and outcrossing, which operate to control transposon activity in populations. In turn, the prevalence of these balancing mechanisms seems to be correlated with external biotic factors, suggesting a complex, interconnected evolutionary network in host-pathogen-microbe interactions. Therefore, the next phase of obligate biotrophic pathogen research will need to uncover how this network, including multitrophic interactions, shapes the evolution and diversity of pathogens. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  19. Analysis and Characterization of Vitamin B Biosynthesis Pathways in the Phytoparasitic Nematode Heterodera Glycines

    Science.gov (United States)

    Craig, James P.

    2009-01-01

    The soybean cyst nematode (SCN), "Heterodera glycines" is an obligate plant parasite that can cause devastating crop losses. To aide in the study of this pathogen, the SCN genome and the transcriptome of second stage juveniles and eggs were shotgun sequenced. A bioinformatic screen of the data revealed nine genes involved in the "de novo"…

  20. Nematode parasites of animals are more prone to develop xenobiotic resistance than nematode parasites of plants

    Directory of Open Access Journals (Sweden)

    Silvestre A.

    2004-06-01

    Full Text Available In this paper, we concentrate on a comparison of plant and animal-parasitic nematodes, to gain insight into the factors that influence the acquisition of the drug resistance by nematodes. Comparing nematode parasite of domestic animals and cultivated plants, it appears that drug resistance threatens only domestic animal production. Does the paucity of report on nematicide field resistance reflect reality or, is nematicide resistance bypassed by other management practices, specific to cultivated plants (i.e. agricultural control ? First, it seems that selection pressure by treatments in plants is not as efficient as selection pressure in ruminants. Agronomic practices (i.e. sanitation, early planting, usage of nematodes resistant cultivar and crop rotation are frequently used to control parasitic-plant nematodes. Although the efficiency of such measures is generally moderate to high, integrated approaches are developing successfully in parasitic-plant nematode models. Secondly, the majority of anthelmintic resistance cases recorded in animal-parasitic nematodes concern drug families that are not used in plant-parasitic nematodes control (i.e. benzimidazoles, avermectines and levamisole. Thirdly, particular life traits of parasitic-plant nematodes (low to moderate fecundity and reproductive strategy are expected to reduce probability of appearance and transmission of drug resistance genes. It has been demonstrated that, for a large number of nematodes such as Meloidogyne spp., the mode of reproduction by mitotic parthenogenesis reduced genetic diversity of populations which may prevent a rapid drug resistance development. In conclusion, anthelmintic resistance develops in nematode parasite of animals as a consequence of an efficient selection pressure. Early detection of anthelmintic resistance is then crucial : it is not possible to avoid it, but only to delay its development in farm animal industry.

  1. Expression of Arabidopsis genes AtNPR1 and AtTGA2 in transgenic soybean roots of composite plants confers resistance to root-knot nematode (Meloidogyne incognita)

    Science.gov (United States)

    Root-knot nematodes (RKN; Meloidogyne spp.) are among the most destructive of the plant parasitic nematodes, infecting almost all cultivated plants and resulting in yield losses of billions of dollars annually. NPR1 (nonexpresser of pathogenesis related genes 1, AtNPR1) plays a positive role in the ...

  2. Molecular Diagnostics and Variability of Longidorid Nematodes

    Directory of Open Access Journals (Sweden)

    Francesca De Luca

    2004-08-01

    Full Text Available PCR-RFLP and sequencing approaches of ribosomal DNA are being used to study taxonomy, molecular identification and phylogeny of plant parasitic nematodes. In this paper, we discuss on the usefulness of ITS PCRRFLP analysis to differentiate among longidorid species. In addition, we examined how well ITS PCR-RFLP differentiated between longidorid species, and how well sequencing of two different ribosomal regions, the ITS containing region and D1-D2 domains of the 26S rDNA, were able to infer phylogenetic relationships among those same species. These methods and their advantages in identifying longidorids and establishing their phylogenetic relationships are examined and discussed.

  3. [Effect of the soil contamination with a potato cyst-forming nematode on the community structure of soil-inhabiting nematodes].

    Science.gov (United States)

    Gruzdeva, L I; Suzhchuk, A A

    2008-01-01

    Nematode community structure of the potato fields with different infection levels of potato cyst-forming nematode (PCN) such as 10, 30 and 214 cysts per 100 g of soil has been investigated. The influence of specialized parasite on nematode fauna and dominance character of different ecological-trophic groups were described. Parasitic nematode genera in natural meadow biocenosis and agrocenoses without PCN are Paratylenchus, Tylenchorhynchus, and Helicotylenchus. It is established, that Paratylenchus nanus was the prevalent species among plant parasites at low infection level. Larvae of Globodera prevailed in the soil with middle and high infection levels and substituted individuals of other genera of parasitic nematodes. The fact of increase in number of hyphal-feeding nematode Aphelenchus avenae was revealed.

  4. Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses

    Science.gov (United States)

    Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins that are delivered to the apoplast, as well as...

  5. Infection Assay of Cyst Nematodes on Arabidopsis Roots.

    Science.gov (United States)

    Bohlmann, Holger; Wieczorek, Krzysztof

    2015-09-20

    Plant parasitic nematodes are devastating pests on many crops. Juveniles (J2) of cyst nematodes invade the roots to induce a syncytium. This feeding site is their only source of nutrients. Male nematodes leave the roots after the fourth molt to mate with females. The females stay attached to their syncytia throughout their life and produce hundreds of eggs, which are contained in their bodies. When the females die their bodies form the cysts, which protect the eggs. Cysts can survive for many years in the soil until favorable conditions induce hatching of the juveniles. The beet cyst nematode Heterodera schachtii ( H. schachtii )is a pathogen of sugar beet ( Beta vulgaris ) but can also complete its life cycle on Arabidopsis roots growing on agar plates under sterile conditions. We present here protocols for a stock culture of H. schachtii and an infection assay on agar plates.

  6. In Vivo Production of Entomopathogenic Nematodes.

    Science.gov (United States)

    Shapiro-Ilan, David I; Morales-Ramos, Juan A; Rojas, M Guadalupe

    2016-01-01

    In nature, entomopathogenic nematodes in the genera Heterorhabditis and Steinernema are obligate parasites of insects. The nematodes are used widely as biopesticides for suppression of insect pests. More than a dozen entomopathogenic nematode species have been commercialized for use in biological control. Most nematodes intended for commercial application are produced in artificial media via solid or liquid fermentation. However, for laboratory research and small greenhouse or field trials, in vivo production of entomopathogenic nematodes is the common method of propagation. Additionally, small companies continue to produce nematodes using in vivo methods for application in niche markets. Advances in mechanization and alternative production routes (e.g., production geared toward application of nematodes in infected host cadavers) can improve efficiency and economy of scale. The objective of this chapter is to describe basic and advanced procedures for in vivo production of entomopathogenic nematodes.

  7. Effectiveness of the native strain of Bacillus subtilis as a suppressant agent of the nematode Meloidogyne spp knot in cultures of Capsicum annuum “piquillo pepper chili”

    Directory of Open Access Journals (Sweden)

    Nancy Mercedes Soto Deza

    2012-05-01

    Full Text Available In croping fields infested with nematodes, the RCBD complete blocks design was applied. 85% pure chicken manure was also incorporated, 15 t / ha and 30 t /. Spores of B. subtilis, 1 X106 eng / mL and 2 x 106 sperm / mL Capsicum annuum seeds in direct seeding were inoculated (experiment I and transplantation (experiment II. At 45 and 90 days analysis of nematode populations were determined, nodulation index, plant height and fruit number. The data was subjected to analysis of variance using the Statgraphics Plus 5.0 software. To estimate the significant differences between treatments, the Tukey test was applied. Initially, the study showed highly infested knot nematode Meloidogyne spp., 275 to 27720 soil nematodes/100 cm3, and in Trial II it was between 9 and 1 nematodes/100 cm3 of soil, with significant difference (P & 0.05. The final population recorded after the application of Bacillus subtilis, was 13 and 0 nematodes/100 cm3 of soil, the nematode  population levels, decreased significantly, showing significant difference (P & 0.05. Efficacy of B. subtilis on Meloidogyne spp., it was clear, reduced initial populations of the nematode, reaching a reproduction rate less than 1, non-galling index reached grade 3. The interaction of B. subtilis with poultry manure amendment favored the production achieved in the cultivation of Capsicum annuum.

  8. Plant nematodes in South Africa. 11. Checklist of plant nematodes of the protected areas of KwaZulu-Natal

    Directory of Open Access Journals (Sweden)

    Mariette Marais

    2013-03-01

    Full Text Available Nematodes are some of the most abundant soil organisms and are an essential part of soil ecology. These organisms are used as indicator organisms and can be linked to soil health. Biological collections contain vast amounts of data, with the National Collection of Nematodes housed at the Plant Protection Research Institute, Agricultural Research Council being no different. During the digitising of the collection a number of unpublished records of plant nematodes reported from protected areas in KwaZulu-Natal were found in the South African Plant-Parasitic Nematode Survey database. A total of 222 plant nematode species belonging to 39 genera were reported from the province, with only 94 of these species reported from the protected areas and 172 and 159 species reported from uncultivated (outside the protected areas and cultivated areas, respectively. Only nine species, Criconema silvum, Criconema talanum, Helicotylenchus marethae, Ogma dracomontanum, Ogma louisi, Ogma ueckermanni, Paralongidorus deborae, Trichodorus rinae and Xiphinemella marindae were described from protected areas, whilst O. dracomontanum, P. deborae and T. rinae were subsequently also reported from other provinces. Conservation implications: A higher degree of diversity of nematodes was observed in the unprotected areas of the province. The observation suggests that nematode fauna, and by implication also other invertebrates, are not adequately protected.

  9. Plant nematodes in South Africa. 11. Checklist of plant nematodes of the protected areas of KwaZulu-Natal

    Directory of Open Access Journals (Sweden)

    Mariette Marais

    2013-02-01

    Full Text Available Nematodes are some of the most abundant soil organisms and are an essential part of soil ecology. These organisms are used as indicator organisms and can be linked to soil health. Biological collections contain vast amounts of data, with the National Collection of Nematodes housed at the Plant Protection Research Institute, Agricultural Research Council being no different. During the digitising of the collection a number of unpublished records of plant nematodes reported from protected areas in KwaZulu-Natal were found in the South African Plant-Parasitic Nematode Survey database. A total of 222 plant nematode species belonging to 39 genera were reported from the province, with only 94 of these species reported from the protected areas and 172 and 159 species reported from uncultivated (outside the protected areas and cultivated areas, respectively. Only nine species, Criconema silvum, Criconema talanum, Helicotylenchus marethae, Ogma dracomontanum, Ogma louisi, Ogma ueckermanni, Paralongidorus deborae, Trichodorus rinae and Xiphinemella marindae were described from protected areas, whilst O. dracomontanum, P. deborae and T. rinae were subsequently also reported from other provinces. Conservation implications: A higher degree of diversity of nematodes was observed in the unprotected areas of the province. The observation suggests that nematode fauna, and by implication also other invertebrates, are not adequately protected.

  10. Nematodes as bioindicators of ecosystem recovery during phytoremediation of crude oil contaminated soil.

    Science.gov (United States)

    Savin, Mary C; Wolf, Duane C; Davis, K Jody; Gbur, Edward E; Thoma, Greg J

    2015-01-01

    Restoration of a weathered crude oil contaminated site undergoing phytoremediation was evaluated using nematodes as bioindicators. Samples were collected twice per year equating to spring and fall/winter. Mean annual total abundances ranged from 18-130 in the non-fertilized non-vegetated control (CTR) to 69-728 in tall fescue-ryegrass (FES) to 147-749 (100 g(-1)) in the fertilized bermudagrass-fescue (BER) treatment. Proportions of plant-parasitic (PP) and free-living (FL) nematodes were significantly impacted by treatment, but not year, with PP nematodes accounting for 27, 59, and 68% of CTR, FES, and BER communities, respectively. There was no significant year by season by treatment or treatment by year effect for total, PP, or FL nematode abundances. Diversity did not increase over time. The BER and FES treatments had more mature communities as indicated by higher plant-parasitic index (PPI) values. Phytoremediation accelerates petroleum degradation and alters the soil habitat which is reflected in the nematode community. However, low numbers and inconsistent presence of persister strategist omnivores and predators, and the lack in improvement over time in treatment effects for total and PP nematode abundances, PP and FL proportions, or PPI indicate the system is being rehabilitated but has not been restored after 69 months of phytoremediation.

  11. Rather than by direct acquisition via lateral gene transfer, GHF5 cellulases were passed on from early Pratylenchidae to root-knot and cyst nematodes

    NARCIS (Netherlands)

    Rybarczyk-Mydlowska, K.D.; Maboreke, H.R.; Megen, van H.H.B.; Elsen, van den S.J.J.; Mooijman, P.J.W.; Smant, G.; Bakker, J.; Helder, J.

    2012-01-01

    Background: Plant parasitic nematodes are unusual Metazoans as they are equipped with genes that allow for symbiont-independent degradation of plant cell walls. Among the cell wall-degrading enzymes, glycoside hydrolase family 5 (GHF5) cellulases are relatively well characterized, especially for

  12. Anaerobic Soil Disinfestation (ASD) Combined with Soil Solarization for Root-Knot Nematode Control in Vegetable and Ornamental Crops in Florida

    Science.gov (United States)

    Anaerobic soil disinfestation (ASD) combined with soil solarization continues to be evaluated for management of plant-parasitic nematodes in vegetable and ornamental crops in Florida. ASD combines organic amendments and soil saturation to stimulate microbial activity and create anaerobic conditions...

  13. The Role of Cytokinin During Infection of Arabidopsis thaliana by the Cyst Nematode Heterodera schachtii.

    Science.gov (United States)

    Shanks, Carly M; Rice, J Hollis; Zubo, Yan; Schaller, G Eric; Hewezi, Tarek; Kieber, Joseph J

    2016-01-01

    Plant-parasitic cyst nematodes induce the formation of hypermetabolic feeding sites, termed syncytia, as their sole source of nutrients. The formation of the syncytium is orchestrated by the nematode, in part, by modulation of phytohormone responses, including cytokinin. In response to infection by the nematode Heterodera schachtii, cytokinin signaling is transiently induced at the site of infection and in the developing syncytium. Arabidopsis lines with reduced cytokinin sensitivity show reduced susceptibility to nematode infection, indicating that cytokinin signaling is required for optimal nematode development. Furthermore, lines with increased cytokinin sensitivity also exhibit reduced nematode susceptibility. To ascertain why cytokinin hypersensitivity reduces nematode parasitism, we examined the transcriptomes in wild type and a cytokinin-hypersensitive type-A arr Arabidopsis mutant in response to H. schachtii infection. Genes involved in the response to biotic stress and defense response were elevated in the type-A arr mutant in the absence of nematodes and were hyperinduced following H. schachtii infection, which suggests that the Arabidopsis type-A arr mutants impede nematode development because they are primed to respond to pathogen infection. These results suggest that cytokinin signaling is required for optimal H. schachtii parasitism of Arabidopsis but that elevated cytokinin signaling triggers a heightened immune response to nematode infection.

  14. Composition and vertical distribution of free living and plant parasitic nematodes in hop gardens in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Čermák, V.; Gaar, V.; Háněl, Ladislav; Široká, K.

    2011-01-01

    Roč. 48, č. 2 (2011), s. 124-136 ISSN 0440-6605 Institutional research plan: CEZ:AV0Z60660521 Keywords : Nematoda * diversity * vertical distribution Subject RIV: EH - Ecology, Behaviour Impact factor: 0.773, year: 2011

  15. Parasitic nematodes modulate PIN-mediated auxin transport to facilitate infection.

    Directory of Open Access Journals (Sweden)

    Wim Grunewald

    2009-01-01

    Full Text Available Plant-parasitic nematodes are destructive plant pathogens that cause significant yield losses. They induce highly specialized feeding sites (NFS in infected plant roots from which they withdraw nutrients. In order to establish these NFS, it is thought that the nematodes manipulate the molecular and physiological pathways of their hosts. Evidence is accumulating that the plant signalling molecule auxin is involved in the initiation and development of the feeding sites of sedentary plant-parasitic nematodes. Intercellular transport of auxin is essential for various aspects of plant growth and development. Here, we analysed the spatial and temporal expression of PIN auxin transporters during the early events of NFS establishment using promoter-GUS/GFP fusion lines. Additionally, single and double pin mutants were used in infection studies to analyse the role of the different PIN proteins during cyst nematode infection. Based on our results, we postulate a model in which PIN1-mediated auxin transport is needed to deliver auxin to the initial syncytial cell, whereas PIN3 and PIN4 distribute the accumulated auxin laterally and are involved in the radial expansion of the NFS. Our data demonstrate that cyst nematodes are able to hijack the auxin distribution network in order to facilitate the infection process.

  16. Parasitic nematodes modulate PIN-mediated auxin transport to facilitate infection.

    Science.gov (United States)

    Grunewald, Wim; Cannoot, Bernard; Friml, Jirí; Gheysen, Godelieve

    2009-01-01

    Plant-parasitic nematodes are destructive plant pathogens that cause significant yield losses. They induce highly specialized feeding sites (NFS) in infected plant roots from which they withdraw nutrients. In order to establish these NFS, it is thought that the nematodes manipulate the molecular and physiological pathways of their hosts. Evidence is accumulating that the plant signalling molecule auxin is involved in the initiation and development of the feeding sites of sedentary plant-parasitic nematodes. Intercellular transport of auxin is essential for various aspects of plant growth and development. Here, we analysed the spatial and temporal expression of PIN auxin transporters during the early events of NFS establishment using promoter-GUS/GFP fusion lines. Additionally, single and double pin mutants were used in infection studies to analyse the role of the different PIN proteins during cyst nematode infection. Based on our results, we postulate a model in which PIN1-mediated auxin transport is needed to deliver auxin to the initial syncytial cell, whereas PIN3 and PIN4 distribute the accumulated auxin laterally and are involved in the radial expansion of the NFS. Our data demonstrate that cyst nematodes are able to hijack the auxin distribution network in order to facilitate the infection process.

  17. Role of mungbean root nodule associated fluorescent Pseudomonas and rhizobia in suppressing the root rotting fungi and root knot nematodes in chickpea (Cicer arietinum L.)

    International Nuclear Information System (INIS)

    Noreen, R.; Shafique, A.; Haque, S.E.; Ali, S.A.

    2016-01-01

    Three isolates each of fluorescent Pseudomonas (NAFP-19, NAFP-31 and NAFP-32) and rhizobia (NFB- 103, NFB-107 and NFB-109) which were originally isolated from root nodules of mungbean (Vigna radiata) showed significant biocontrol activity in the screen house and under field condition, against root rotting fungi viz., Macrophomina phaseolina, Fusarium solani, F. oxysporum and Rhizoctonia solani evaluated on chickpea. Biocontrol potential of these isolates was also evaluated against Meloidogyne incognita, the root knot nematode. Application of Pseudomonas and rhizobial isolates as a soil drench, separately or mixed significantly reduced root rot disease under screen house and field conditions. Nematode penetration in roots was also found significantly less in rhizobia or Pseudomonas treatments used separately or mixed as compared to control. Fluorescent Pseudomonas treated plants produced greater number of nodules per plant than control plants and about equal to rhizobia treated plants, indicating that root nodule associated fluorescent Pseudomonas enhance root nodulation. (author)

  18. Biotransformation of (-)-dihydromyrcenyl acetate using the plant parasitic fungus Glomerella cingulata as a biocatalyst.

    Science.gov (United States)

    Miyazawa, M; Akazawa, S i; Sakai, H; Nankai, H

    2000-10-01

    The microbial transformation of (-)-dihydromyrcenyl acetate was investigated using the plant parasitic fungus Glomerella cingulata. As a result, (-)-dihydromyrcenyl acetate was converted to dihydromyrcenol, 3,7-dihydroxy-3,7-dimethyl-1-octene-7-carboxylate, 3,7-dihydroxy-3,7-dimethyl-1-octene, 3,7-dimethyloctane-1,2, 7-triol-7-carboxylate, and 3,7-dimethyloctane-1,2,7-triol. In addition, microbial transformation of dihydromyrcenol by G. cingulata was carried out. The metabolic pathway of (-)-dihydromyrcenyl acetate is discussed.

  19. A parasitic nematode releases cytokinin that controls cell division and orchestrates feeding site formation in host plants.

    Science.gov (United States)

    Siddique, Shahid; Radakovic, Zoran S; De La Torre, Carola M; Chronis, Demosthenis; Novák, Ondřej; Ramireddy, Eswarayya; Holbein, Julia; Matera, Christiane; Hütten, Marion; Gutbrod, Philipp; Anjam, Muhammad Shahzad; Rozanska, Elzbieta; Habash, Samer; Elashry, Abdelnaser; Sobczak, Miroslaw; Kakimoto, Tatsuo; Strnad, Miroslav; Schmülling, Thomas; Mitchum, Melissa G; Grundler, Florian M W

    2015-10-13

    Sedentary plant-parasitic cyst nematodes are biotrophs that cause significant losses in agriculture. Parasitism is based on modifications of host root cells that lead to the formation of a hypermetabolic feeding site (a syncytium) from which nematodes withdraw nutrients. The host cell cycle is activated in an initial cell selected by the nematode for feeding, followed by activation of neighboring cells and subsequent expansion of feeding site through fusion of hundreds of cells. It is generally assumed that nematodes manipulate production and signaling of the plant hormone cytokinin to activate cell division. In fact, nematodes have been shown to produce cytokinin in vitro; however, whether the hormone is secreted into host plants and plays a role in parasitism remained unknown. Here, we analyzed the spatiotemporal activation of cytokinin signaling during interaction between the cyst nematode, Heterodera schachtii, and Arabidopsis using cytokinin-responsive promoter:reporter lines. Our results showed that cytokinin signaling is activated not only in the syncytium but also in neighboring cells to be incorporated into syncytium. An analysis of nematode infection on mutants that are deficient in cytokinin or cytokinin signaling revealed a significant decrease in susceptibility of these plants to nematodes. Further, we identified a cytokinin-synthesizing isopentenyltransferase gene in H. schachtii and show that silencing of this gene in nematodes leads to a significant decrease in virulence due to a reduced expansion of feeding sites. Our findings demonstrate the ability of a plant-parasitic nematode to synthesize a functional plant hormone to manipulate the host system and establish a long-term parasitic interaction.

  20. Glutathione peroxidases of the potato cyst nematode Globodera Rostochiensis.

    Science.gov (United States)

    Jones, J T; Reavy, B; Smant, G; Prior, A E

    2004-01-07

    We report the cloning and characterisation of full-length DNAs complementary to RNA (cDNAs) encoding two glutathione peroxidases (GpXs) from a plant parasitic nematode, the potato cyst nematode (PCN) Globodera rostochiensis. One protein has a functional signal peptide that targets the protein for secretion from animal cells while the other is predicted to be intracellular. Both genes are expressed in all parasite stages tested. The mRNA encoding the intracellular GpX is present throughout the nematode second stage juvenile and is particularly abundant in metabolically active tissues including the genital primordia. The mRNA encoding the secreted GpX is restricted to the hypodermis, the outermost cellular layer of the nematode, a location from which it is likely to be secreted to the parasite surface. Biochemical studies confirmed the secreted protein as a functional GpX and showed that, like secreted GpXs of other parasitic nematodes, it does not metabolise hydrogen peroxide but has a preference for larger hydroperoxide substrates. The intracellular protein is likely to have a role in metabolism of active oxygen species derived from internal body metabolism while the secreted protein may protect the parasite from host defences. Other functional roles for this protein are discussed.

  1. Population Genetics of Hirsutella rhossiliensis, a Dominant Parasite of Cyst Nematode Juveniles on a Continental Scale.

    Science.gov (United States)

    Wang, Niuniu; Zhang, Yongjie; Jiang, Xianzhi; Shu, Chi; Hamid, M Imran; Hussain, Muzammil; Chen, Senyu; Xu, Jianping; Xiang, Meichun; Liu, Xingzhong

    2016-11-01

    Hirsutella rhossiliensis is a parasite of juvenile nematodes, effective against a diversity of plant-parasitic nematodes. Its global distribution on various nematode hosts and its genetic variation for several geographic regions have been reported, while the global population genetic structure and factors underlying patterns of genetic variation of H. rhossiliensis are unclear. In this study, 87 H. rhossiliensis strains from five nematode species (Globodera sp., Criconemella xenoplax, Rotylenchus robustus, Heterodera schachtii, and Heterodera glycines) in Europe, the United States, and China were investigated by multilocus sequence analyses. A total of 280 variable sites (frequency, 0.6%) at eight loci and six clustering in high accordance with geographic populations or host nematode-associated populations were identified. Although H. rhossiliensis is currently recognized as an asexual fungus, recombination events were frequently detected. In addition, significant genetic isolation by geography and nematode hosts was revealed. Overall, our analyses showed that recombination, geographic isolation, and nematode host adaptation have played significant roles in the evolutionary history of H. rhossiliensis IMPORTANCE: H. rhossiliensis has great potential for use as a biocontrol agent to control nematodes in a sustainable manner as an endoparasitic fungus. Therefore, this study has important implications for the use of H. rhossiliensis as a biocontrol agent and provides interesting insights into the biology of this species. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  2. Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses

    Directory of Open Access Journals (Sweden)

    Peter eMoffett

    2015-08-01

    Full Text Available Potato cyst nematodes (PCNs, including Globodera rostochiensis (Woll., are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from G. rostochiensis predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC family. SPRYSEC proteins are unique to members of the genera Globodera and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different G. rostochiensis SPRYSEC proteins by expressing them in Nicotiana benthamiana and N. tabacum. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time, GrSPRYSEC-15 elicited a defense response in N. tabacum, and tobacco was found to be resistant to a virus expressing GrSPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system.

  3. Analysis of Globodera rostochiensis effectors reveals conserved functions of SPRYSEC proteins in suppressing and eliciting plant immune responses

    KAUST Repository

    Ali, Shawkat

    2015-08-11

    Potato cyst nematodes (PCNs), including Globodera rostochiensis (Woll.), are important pests of potato. Plant parasitic nematodes produce multiple effector proteins, secreted from their stylets, to successfully infect their hosts. These include proteins delivered to the apoplast and to the host cytoplasm. A number of effectors from G. rostochiensis predicted to be delivered to the host cytoplasm have been identified, including several belonging to the secreted SPRY domain (SPRYSEC) family. SPRYSEC proteins are unique to members of the genus Globodera and have been implicated in both the induction and the repression of host defense responses. We have tested the properties of six different G. rostochiensis SPRYSEC proteins by expressing them in Nicotiana benthamiana and N. tabacum. We have found that all SPRYSEC proteins tested are able to suppress defense responses induced by NB-LRR proteins as well as cell death induced by elicitors, suggesting that defense repression is a common characteristic of members of this effector protein family. At the same time, GrSPRYSEC-15 elicited a defense responses in N. tabacum, which was found to be resistant to a virus expressing GrSPRYSEC-15. These results suggest that SPRYSEC proteins may possess characteristics that allow them to be recognized by the plant immune system.

  4. Survey of crop losses in response to phytoparasitic nematodes in the United States for 1994.

    Science.gov (United States)

    Koenning, S R; Overstreet, C; Noling, J W; Donald, P A; Becker, J O; Fortnum, B A

    1999-12-01

    Previous reports of crop losses to plant-parasitic nematodes have relied on published results of survey data based on certain commodities, including tobacco, peanuts, cotton, and soybean. Reports on crop-loss assessment by land-grant universities and many commodity groups generally are no longer available, with the exception of the University of Georgia, the Beltwide Cotton Conference, and selected groups concerned with soybean. The Society of Nematologists Extension Committee contacted extension personnel in 49 U.S. states for information on estimated crop losses caused by plant-parasitic nematodes in major crops for the year 1994. Included in this paper are survey results from 35 states on various crops including corn, cotton, soybean, peanut, wheat, rice, sugarcane, sorghum, tobacco, numerous vegetable crops, fruit and nut crops, and golf greens. The data are reported systematically by state and include the estimated loss, hectarage of production, source of information, nematode species or taxon when available, and crop value. The major genera of phytoparasitic nematodes reported to cause crop losses were Heterodera, Hoplolaimus, Meloidogyne, Pratylenchus, Rotylenchulus, and Xiphinema.

  5. Analysis of the Transcriptome of the Infective Stage of the Beet Cyst Nematode, H. schachtii.

    Directory of Open Access Journals (Sweden)

    John Fosu-Nyarko

    Full Text Available The beet cyst nematode, Heterodera schachtii, is a major root pest that significantly impacts the yield of sugar beet, brassicas and related species. There has been limited molecular characterisation of this important plant pathogen: to identify target genes for its control the transcriptome of the pre-parasitic J2 stage of H. schachtii was sequenced using Roche GS FLX. Ninety seven percent of reads (i.e., 387,668 with an average PHRED score > 22 were assembled with CAP3 and CLC Genomics Workbench into 37,345 and 47,263 contigs, respectively. The transcripts were annotated by comparing with gene and genomic sequences of other nematodes and annotated proteins on public databases. The annotated transcripts were much more similar to sequences of Heterodera glycines than to those of Globodera pallida and root knot nematodes (Meloidogyne spp.. Analysis of these transcripts showed that a subset of 2,918 transcripts was common to free-living and plant parasitic nematodes suggesting that this subset is involved in general nematode metabolism and development. A set of 148 contigs and 183 singletons encoding putative homologues of effectors previously characterised for plant parasitic nematodes were also identified: these are known to be important for parasitism of host plants during migration through tissues or feeding from cells or are thought to be involved in evasion or modulation of host defences. In addition, the presence of sequences from a nematode virus is suggested. The sequencing and annotation of this transcriptome significantly adds to the genetic data available for H. schachtii, and identifies genes primed to undertake required roles in the critical pre-parasitic and early post-parasitic J2 stages. These data provide new information for identifying potential gene targets for future protection of susceptible crops against H. schachtii.

  6. [Diversity of soil nematode communities in the subalpine and alpine forests of western Sichuan, China.

    Science.gov (United States)

    Chen, Ya; Yang, Wan Qin; Wu, Fu Zhong; Yang, Fan; Lan, Li Ying; Liu, Yu Wei; Guo, Cai Hong; Tan, Bo

    2017-10-01

    In order to understand the diversity of soil nematodes in the subalpine/alpine forests of the eastern Qinghai-Tibet Plateau, soil nematodes in the primary forest, mixed forest and secondary forest of Abies faxoniana were extracted by elutriation and sugar-centrifugation method in July 2015, and the composition and structure characteristics of soil nematode communities were studied in the three forests at different altitudes. A total of 37950 soil nematodes were collected, which belonged to 20 families and 27 genera, and the mean density was 4217 ind·100 g -1 dry soil. Filenchus was the dominant genus in the primary forest, and Filenchus and Pararotylenchus in the mixed forest and secondary forest, respectively. The individual number of each dominant genus was significantly affected by forest type. All nematode individuals were classified into the four trophic groups of bacterivores, fungivores, plant-parasites and omnivore-predators. The fungivores were dominant in the primary and secondary forest and the bacterivores in the mixed forest. The number of soil nematode c-p (colonizer-persister) groups of c-p 1, c-p 2, c-p 3 and c-p 4 accounted for 6.1%, 51.1%, 30.0% and 12.7% of the total nematode abundance, respectively. The maturity index (MI), the total maturity index (∑MI) and the plant parasitic index (PPI) of soil nematodes decreased gradually with the increase of altitude. The nematode channel ratio in the mixed forest was higher than 0.5, but that in the primary forest and secondary forest was below 0.5. The forest type significantly affected the soil nematode maturity index and channel ratio, but the forest type, soil layer and their interaction had no significant effect on the diversity index. There were obvious diffe-rences in the composition, nutrient structure and energy flow channel of soil nematodes in the subalpine/alpine forests of western Sichuan, providing an important reference for understanding the function of soil nematodes in soil processes

  7. Mate Finding, Sexual Spore Production, and the Spread of Fungal Plant Parasites.

    Science.gov (United States)

    Hamelin, Frédéric M; Castella, François; Doli, Valentin; Marçais, Benoît; Ravigné, Virginie; Lewis, Mark A

    2016-04-01

    Sexual reproduction and dispersal are often coupled in organisms mixing sexual and asexual reproduction, such as fungi. The aim of this study is to evaluate the impact of mate limitation on the spreading speed of fungal plant parasites. Starting from a simple model with two coupled partial differential equations, we take advantage of the fact that we are interested in the dynamics over large spatial and temporal scales to reduce the model to a single equation. We obtain a simple expression for speed of spread, accounting for both sexual and asexual reproduction. Taking Black Sigatoka disease of banana plants as a case study, the model prediction is in close agreement with the actual spreading speed (100 km per year), whereas a similar model without mate limitation predicts a wave speed one order of magnitude greater. We discuss the implications of these results to control parasites in which sexual reproduction and dispersal are intrinsically coupled.

  8. Geography and major host evolutionary transitions shape the resource use of plant parasites.

    Science.gov (United States)

    Calatayud, Joaquín; Hórreo, José Luis; Madrigal-González, Jaime; Migeon, Alain; Rodríguez, Miguel Á; Magalhães, Sara; Hortal, Joaquín

    2016-08-30

    The evolution of resource use in herbivores has been conceptualized as an analog of the theory of island biogeography, assuming that plant species are islands separated by phylogenetic distances. Despite its usefulness, this analogy has paradoxically led to neglecting real biogeographical processes in the study of macroevolutionary patterns of herbivore-plant interactions. Here we show that host use is mostly determined by the geographical cooccurrence of hosts and parasites in spider mites (Tetranychidae), a globally distributed group of plant parasites. Strikingly, geography accounts for most of the phylogenetic signal in host use by these parasites. Beyond geography, only evolutionary transitions among major plant lineages (i.e., gymnosperms, commelinids, and eudicots) shape resource use patterns in these herbivores. Still, even these barriers have been repeatedly overcome in evolutionary time, resulting in phylogenetically diverse parasite communities feeding on similar hosts. Therefore, our results imply that patterns of apparent evolutionary conservatism may largely be a byproduct of the geographic cooccurrence of hosts and parasites.

  9. Ectopic expression of AtPAD4 broadens resistance of soybean to soybean cyst and root-knot nematodes.

    Science.gov (United States)

    Youssef, Reham M; MacDonald, Margaret H; Brewer, Eric P; Bauchan, Gary R; Kim, Kyung-Hwan; Matthews, Benjamin F

    2013-04-25

    The gene encoding PAD4 (PHYTOALEXIN-DEFICIENT4) is required in Arabidopsis for expression of several genes involved in the defense response to Pseudomonas syringae pv. maculicola. AtPAD4 (Arabidopsis thaliana PAD4) encodes a lipase-like protein that plays a regulatory role mediating salicylic acid signaling. We expressed the gene encoding AtPAD4 in soybean roots of composite plants to test the ability of AtPAD4 to deter plant parasitic nematode development. The transformed roots were challenged with two different plant parasitic nematode genera represented by soybean cyst nematode (SCN; Heterodera glycines) and root-knot nematode (RKN; Meloidogyne incognita). Expression of AtPAD4 in soybean roots decreased the number of mature SCN females 35 days after inoculation by 68 percent. Similarly, soybean roots expressing AtPAD4 exhibited 77 percent fewer galls when challenged with RKN. Our experiments show that AtPAD4 can be used in an economically important crop, soybean, to provide a measure of resistance to two different genera of nematodes.

  10. Co-operative suppression of inflammatory responses in human dendritic cells by plant proanthocyanidins and products from the parasitic nematode Trichuris suis

    DEFF Research Database (Denmark)

    Williams, Andrew R; Klaver, Elsenoor J; Laan, Lisa C

    2017-01-01

    Interactions between dendritic cells (DCs) and environmental, dietary and pathogen antigens play a key role in immune homeostasis and regulation of inflammation. Dietary polyphenols such as proanthocyanidins (PAC) may reduce inflammation, and we therefore hypothesized that PAC may suppress lipopo...

  11. Foxp3⁺ regulatory T cells delay expulsion of intestinal nematodes by suppression of IL-9-driven mast cell activation in BALB/c but not in C57BL/6 mice.

    Directory of Open Access Journals (Sweden)

    Birte Blankenhaus

    2014-02-01

    Full Text Available Accumulating evidence suggests that IL-9-mediated immunity plays a fundamental role in control of intestinal nematode infection. Here we report a different impact of Foxp3⁺ regulatory T cells (Treg in nematode-induced evasion of IL-9-mediated immunity in BALB/c and C57BL/6 mice. Infection with Strongyloides ratti induced Treg expansion with similar kinetics and phenotype in both strains. Strikingly, Treg depletion reduced parasite burden selectively in BALB/c but not in C57BL/6 mice. Treg function was apparent in both strains as Treg depletion increased nematode-specific humoral and cellular Th2 response in BALB/c and C57BL/6 mice to the same extent. Improved resistance in Treg-depleted BALB/c mice was accompanied by increased production of IL-9 and accelerated degranulation of mast cells. In contrast, IL-9 production was not significantly elevated and kinetics of mast cell degranulation were unaffected by Treg depletion in C57BL/6 mice. By in vivo neutralization, we demonstrate that increased IL-9 production during the first days of infection caused accelerated mast cell degranulation and rapid expulsion of S. ratti adults from the small intestine of Treg-depleted BALB/c mice. In genetically mast cell-deficient (Cpa3-Cre BALB/c mice, Treg depletion still resulted in increased IL-9 production but resistance to S. ratti infection was lost, suggesting that IL-9-driven mast cell activation mediated accelerated expulsion of S. ratti in Treg-depleted BALB/c mice. This IL-9-driven mast cell degranulation is a central mechanism of S. ratti expulsion in both, BALB/c and C57BL/6 mice, because IL-9 injection reduced and IL-9 neutralization increased parasite burden in the presence of Treg in both strains. Therefore our results suggest that Foxp3⁺ Treg suppress sufficient IL-9 production for subsequent mast cell degranulation during S. ratti infection in a non-redundant manner in BALB/c mice, whereas additional regulatory pathways are functional in

  12. Foxp3+ Regulatory T Cells Delay Expulsion of Intestinal Nematodes by Suppression of IL-9-Driven Mast Cell Activation in BALB/c but Not in C57BL/6 Mice

    Science.gov (United States)

    Brenz, Yannick; Eschbach, Marie-Luise; Hartmann, Wiebke; Haben, Irma; Sparwasser, Tim; Huehn, Jochen; Kühl, Anja; Feyerabend, Thorsten B.; Rodewald, Hans-Reimer; Breloer, Minka

    2014-01-01

    Accumulating evidence suggests that IL-9-mediated immunity plays a fundamental role in control of intestinal nematode infection. Here we report a different impact of Foxp3+ regulatory T cells (Treg) in nematode-induced evasion of IL-9-mediated immunity in BALB/c and C57BL/6 mice. Infection with Strongyloides ratti induced Treg expansion with similar kinetics and phenotype in both strains. Strikingly, Treg depletion reduced parasite burden selectively in BALB/c but not in C57BL/6 mice. Treg function was apparent in both strains as Treg depletion increased nematode-specific humoral and cellular Th2 response in BALB/c and C57BL/6 mice to the same extent. Improved resistance in Treg-depleted BALB/c mice was accompanied by increased production of IL-9 and accelerated degranulation of mast cells. In contrast, IL-9 production was not significantly elevated and kinetics of mast cell degranulation were unaffected by Treg depletion in C57BL/6 mice. By in vivo neutralization, we demonstrate that increased IL-9 production during the first days of infection caused accelerated mast cell degranulation and rapid expulsion of S. ratti adults from the small intestine of Treg-depleted BALB/c mice. In genetically mast cell-deficient (Cpa3-Cre) BALB/c mice, Treg depletion still resulted in increased IL-9 production but resistance to S. ratti infection was lost, suggesting that IL-9-driven mast cell activation mediated accelerated expulsion of S. ratti in Treg-depleted BALB/c mice. This IL-9-driven mast cell degranulation is a central mechanism of S. ratti expulsion in both, BALB/c and C57BL/6 mice, because IL-9 injection reduced and IL-9 neutralization increased parasite burden in the presence of Treg in both strains. Therefore our results suggest that Foxp3+ Treg suppress sufficient IL-9 production for subsequent mast cell degranulation during S. ratti infection in a non-redundant manner in BALB/c mice, whereas additional regulatory pathways are functional in Treg-depleted C57BL/6

  13. Foxp3⁺ regulatory T cells delay expulsion of intestinal nematodes by suppression of IL-9-driven mast cell activation in BALB/c but not in C57BL/6 mice.

    Science.gov (United States)

    Blankenhaus, Birte; Reitz, Martina; Brenz, Yannick; Eschbach, Marie-Luise; Hartmann, Wiebke; Haben, Irma; Sparwasser, Tim; Huehn, Jochen; Kühl, Anja; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Breloer, Minka

    2014-02-01

    Accumulating evidence suggests that IL-9-mediated immunity plays a fundamental role in control of intestinal nematode infection. Here we report a different impact of Foxp3⁺ regulatory T cells (Treg) in nematode-induced evasion of IL-9-mediated immunity in BALB/c and C57BL/6 mice. Infection with Strongyloides ratti induced Treg expansion with similar kinetics and phenotype in both strains. Strikingly, Treg depletion reduced parasite burden selectively in BALB/c but not in C57BL/6 mice. Treg function was apparent in both strains as Treg depletion increased nematode-specific humoral and cellular Th2 response in BALB/c and C57BL/6 mice to the same extent. Improved resistance in Treg-depleted BALB/c mice was accompanied by increased production of IL-9 and accelerated degranulation of mast cells. In contrast, IL-9 production was not significantly elevated and kinetics of mast cell degranulation were unaffected by Treg depletion in C57BL/6 mice. By in vivo neutralization, we demonstrate that increased IL-9 production during the first days of infection caused accelerated mast cell degranulation and rapid expulsion of S. ratti adults from the small intestine of Treg-depleted BALB/c mice. In genetically mast cell-deficient (Cpa3-Cre) BALB/c mice, Treg depletion still resulted in increased IL-9 production but resistance to S. ratti infection was lost, suggesting that IL-9-driven mast cell activation mediated accelerated expulsion of S. ratti in Treg-depleted BALB/c mice. This IL-9-driven mast cell degranulation is a central mechanism of S. ratti expulsion in both, BALB/c and C57BL/6 mice, because IL-9 injection reduced and IL-9 neutralization increased parasite burden in the presence of Treg in both strains. Therefore our results suggest that Foxp3⁺ Treg suppress sufficient IL-9 production for subsequent mast cell degranulation during S. ratti infection in a non-redundant manner in BALB/c mice, whereas additional regulatory pathways are functional in Treg-depleted C57BL/6

  14. Functional Characterization of a Novel Class of Morantel-Sensitive Acetylcholine Receptors in Nematodes.

    Directory of Open Access Journals (Sweden)

    Elise Courtot

    2015-12-01

    Full Text Available Acetylcholine receptors are pentameric ligand-gated channels involved in excitatory neuro-transmission in both vertebrates and invertebrates. In nematodes, they represent major targets for cholinergic agonist or antagonist anthelmintic drugs. Despite the large diversity of acetylcholine-receptor subunit genes present in nematodes, only a few receptor subtypes have been characterized so far. Interestingly, parasitic nematodes affecting human or animal health possess two closely related members of this gene family, acr-26 and acr-27 that are essentially absent in free-living or plant parasitic species. Using the pathogenic parasitic nematode of ruminants, Haemonchus contortus, as a model, we found that Hco-ACR-26 and Hco-ACR-27 are co-expressed in body muscle cells. We demonstrated that co-expression of Hco-ACR-26 and Hco-ACR-27 in Xenopus laevis oocytes led to the functional expression of an acetylcholine-receptor highly sensitive to the anthelmintics morantel and pyrantel. Importantly we also reported that ACR-26 and ACR-27, from the distantly related parasitic nematode of horses, Parascaris equorum, also formed a functional acetylcholine-receptor highly sensitive to these two drugs. In Caenorhabditis elegans, a free-living model nematode, we demonstrated that heterologous expression of the H. contortus and P. equorum receptors drastically increased its sensitivity to morantel and pyrantel, mirroring the pharmacological properties observed in Xenopus oocytes. Our results are the first to describe significant molecular determinants of a novel class of nematode body wall muscle AChR.

  15. Functional Characterization of a Novel Class of Morantel-Sensitive Acetylcholine Receptors in Nematodes

    Science.gov (United States)

    Courtot, Elise; Charvet, Claude L.; Beech, Robin N.; Harmache, Abdallah; Wolstenholme, Adrian J.; Holden-Dye, Lindy; O’Connor, Vincent; Peineau, Nicolas; Woods, Debra J.; Neveu, Cedric

    2015-01-01

    Acetylcholine receptors are pentameric ligand–gated channels involved in excitatory neuro-transmission in both vertebrates and invertebrates. In nematodes, they represent major targets for cholinergic agonist or antagonist anthelmintic drugs. Despite the large diversity of acetylcholine-receptor subunit genes present in nematodes, only a few receptor subtypes have been characterized so far. Interestingly, parasitic nematodes affecting human or animal health possess two closely related members of this gene family, acr-26 and acr-27 that are essentially absent in free-living or plant parasitic species. Using the pathogenic parasitic nematode of ruminants, Haemonchus contortus, as a model, we found that Hco-ACR-26 and Hco-ACR-27 are co-expressed in body muscle cells. We demonstrated that co-expression of Hco-ACR-26 and Hco-ACR-27 in Xenopus laevis oocytes led to the functional expression of an acetylcholine-receptor highly sensitive to the anthelmintics morantel and pyrantel. Importantly we also reported that ACR-26 and ACR-27, from the distantly related parasitic nematode of horses, Parascaris equorum, also formed a functional acetylcholine-receptor highly sensitive to these two drugs. In Caenorhabditis elegans, a free-living model nematode, we demonstrated that heterologous expression of the H. contortus and P. equorum receptors drastically increased its sensitivity to morantel and pyrantel, mirroring the pharmacological properties observed in Xenopus oocytes. Our results are the first to describe significant molecular determinants of a novel class of nematode body wall muscle AChR. PMID:26625142

  16. Mitochondrial genome diversity in dagger and needle nematodes (Nematoda: Longidoridae).

    Science.gov (United States)

    Palomares-Rius, J E; Cantalapiedra-Navarrete, C; Archidona-Yuste, A; Blok, V C; Castillo, P

    2017-02-02

    Dagger and needle nematodes included in the family Longidoridae (viz. Longidorus, Paralongidorus, and Xiphinema) are highly polyphagous plant-parasitic nematodes in wild and cultivated plants and some of them are plant-virus vectors (nepovirus). The mitochondrial (mt) genomes of the dagger and needle nematodes, Xiphinema rivesi, Xiphinema pachtaicum, Longidorus vineacola and Paralongidorus litoralis were sequenced in this study. The four circular mt genomes have an estimated size of 12.6, 12.5, 13.5 and 12.7 kb, respectively. Up to date, the mt genome of X. pachtaicum is the smallest genome found in Nematoda. The four mt genomes contain 12 protein-coding genes (viz. cox1-3, nad1-6, nad4L, atp6 and cob) and two ribosomal RNA genes (rrnL and rrnS), but the atp8 gene was not detected. These mt genomes showed a gene arrangement very different within the Longidoridae species sequenced, with the exception of very closely related species (X. americanum and X. rivesi). The sizes of non-coding regions in the Longidoridae nematodes were very small and were present in a few places in the mt genome. Phylogenetic analysis of all coding genes showed a closer relationship between Longidorus and Paralongidorus and different phylogenetic possibilities for the three Xiphinema species.

  17. Palaeosymbiosis revealed by genomic fossils of Wolbachia in a strongyloidean nematode.

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    Georgios Koutsovoulos

    2014-06-01

    Full Text Available Wolbachia are common endosymbionts of terrestrial arthropods, and are also found in nematodes: the animal-parasitic filaria, and the plant-parasite Radopholus similis. Lateral transfer of Wolbachia DNA to the host genome is common. We generated a draft genome sequence for the strongyloidean nematode parasite Dictyocaulus viviparus, the cattle lungworm. In the assembly, we identified nearly 1 Mb of sequence with similarity to Wolbachia. The fragments were unlikely to derive from a live Wolbachia infection: most were short, and the genes were disabled through inactivating mutations. Many fragments were co-assembled with definitively nematode-derived sequence. We found limited evidence of expression of the Wolbachia-derived genes. The D. viviparus Wolbachia genes were most similar to filarial strains and strains from the host-promiscuous clade F. We conclude that D. viviparus was infected by Wolbachia in the past, and that clade F-like symbionts may have been the source of filarial Wolbachia infections.

  18. Prevalence of Pasteuria SP. on Renfirom Nematode in a Georgia Cotton Field

    Science.gov (United States)

    Pasteuria species are bacterial parasites of nematodes and have been associated with suppression of root-knot, sting, and cyst nematode populations. Little is known about the Pasteuria sp. infecting the reniform nematode. While sampling a cotton field study near Cochran, GA, we found Pasteuria spo...

  19. A SNARE-like protein and biotin are implicated in soybean cyst nematode virulence

    Science.gov (United States)

    Some phytoparasitic nematodes have the ability to infect and reproduce on plants that are normally considered resistant to nematode infection. Such nematodes are referred to as virulent and the mechanisms they use to evade or suppress host plant defenses are not well understood. Here, we report the ...

  20. A Standardized Method to Assess Infection Rates of Root-Knot and Cyst Nematodes in Arabidopsis thaliana Mutants with Alterations in Root Development Related to Auxin and Cytokinin Signaling.

    Science.gov (United States)

    Olmo, Rocío; Silva, Ana Cláudia; Díaz-Manzano, Fernando E; Cabrera, Javier; Fenoll, Carmen; Escobar, Carolina

    2017-01-01

    Plant parasitic nematodes cause a great impact in agricultural systems. The search for effective control methods is partly based on the understanding of underlying molecular mechanisms leading to the formation of nematode feeding sites. In this respect, crosstalk of hormones such as auxins and cytokinins (IAA, CK) between the plant and the nematode seems to be crucial. Thence, the study of loss of function or overexpressing lines with altered IAA and CK functioning is entailed. Those lines frequently show developmental defects in the number, position and/or length of the lateral roots what could generate a bias in the interpretation of the nematode infection parameters. Here we present a protocol to assess differences in nematode infectivity with the lowest interference of root architecture phenotypes in the results. Thus, tailored growth conditions and normalization parameters facilitate the standardized phenotyping of nematode infection.

  1. Molecular diversity of bacterial endosymbionts associated with dagger nematodes of the genus Xiphinema (Nematoda: Longidoridae) reveals a high degree of phylogenetic congruence with their host.

    Science.gov (United States)

    Palomares-Rius, Juan E; Archidona-Yuste, Antonio; Cantalapiedra-Navarrete, Carolina; Prieto, Pilar; Castillo, Pablo

    2016-12-01

    Bacterial endosymbionts have been detected in some groups of plant-parasitic nematodes, but few cases have been reported compared to other groups in the phylum Nematoda, such as animal-parasitic or free-living nematodes. This study was performed on a wide variety of plant-parasitic nematode families and species from different host plants and nematode populations. A total of 124 nematode populations (previously identified morphologically and molecularly) were screened for the presence of potential bacterial endosymbionts using the partial 16S rRNA gene and fluorescence in situ hybridization (FISH) and confocal microscopy. Potential bacterial endosymbionts were only detected in nematode species belonging to the genus Xiphinema and specifically in the X. americanum group. Fifty-seven partial 16S rRNA sequences were obtained from bacterial endosymbionts in this study. One group of sequences was closely related to the genus 'Candidatus Xiphinematobacter' (19 bacterial endosymbiont sequences were associated with seven nematode host species, including two that have already been described and three unknown bacterial endosymbionts). The second bacterial endosymbiont group (38 bacterial endosymbiont sequences associated with six nematode species) was related to the family Burkholderiaceae, which includes fungal and soil-plant bacterial endosymbionts. These endosymbionts were reported for the first time in the phylum Nematoda. Our findings suggest that there is a highly specific symbiotic relationship between nematode host and bacterial endosymbionts. Overall, these results were corroborated by a phylogeny of nematode host and bacterial endosymbionts that suggested that there was a high degree of phylogenetic congruence and long-term evolutionary persistence between hosts and endosymbionts. © 2016 John Wiley & Sons Ltd.

  2. Studies of nematode population of damaged forest ecosystems with special regard to phytopathogen species able to transmit viruses. Final report. Untersuchungen ueber Nematodenpopulationen in geschaedigten Waldoekosystemen unter besonderer Beruecksichtigung von pflanzenpathogenen Arten mit Virusuebertraegereigenschaften. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, R A; Gierlich, D; Lasthaus, U

    1989-02-01

    Over 250 soil and root samples were collected from forest nurseries and regional research plots as well as from open-air and open-top chambers. The samples were examined for plant parasitic, mycophagous and microphagous nematode and for nematodes able to transmit plant viruses. The results allow conclusions to be drawn concerning nematode population dynamics and the composition of the various trophic groups as related to intensity of forest decline in each station and to some extent to the pH level of the soil. (orig./MG).

  3. Short-term effects of forest disturbances on soil nematode communities in European mountain spruce forests.

    Science.gov (United States)

    Čerevková, A; Renčo, M; Cagáň, L

    2013-09-01

    The nematode communities in spruce forests were compared with the short-term effects of forest damage, caused by windstorm, wildfire and management practices of forest soils. Soil samples were collected in June and October from 2006 to 2008 in four different sites: (1) forest unaffected by the wind (REF); (2) storm-felled forest with salvaged timber (EXT); (3) modified forest affected by timber salvage (wood removal) and forest fire (FIR); and (4) storm-felled forest where timber had been left unsalvaged (NEX). Nematode analysis showed that the dominant species in all four investigated sites were Acrobeloides nanus and Eudorylaimus silvaticus. An increase of A. nanus (35% of the total nematode abundance) in the first year in the FIR site led to the highest total abundance of nematodes compared with other sites, where nematode abundance reached the same level in the third year. In the FIR site bacterial feeders appeared to be the most representative trophic group, although in the second and third year, after disturbance, the abundance of this trophic group gradually decreased. In the NEX site, the number of nematode species, population densities and Maturity Index were similar to that recorded for the FIR site. In EXT and NEX sites, the other dominant species was the plant parasitic nematode Paratylenchus microdorus. Analyses of nematodes extracted from different forest soil samples showed that the highest number of species and diversity index for species (H'spp) were in the REF site. Differences between the nematode fauna in REF and other localities were clearly depicted by cluster analysis. The greatest Structure Index and Enrichment Index values were also in REF. In the EXT site, the number of nematode species, their abundance, H'spp and Maturity Index were not significantly different from those recorded in the reference site.

  4. MicroRNA discovery and analysis of pinewood nematode Bursaphelenchus xylophilus by deep sequencing.

    Directory of Open Access Journals (Sweden)

    Qi-Xing Huang

    Full Text Available BACKGROUND: MicroRNAs (miRNAs are considered to be very important in regulating the growth, development, behavior and stress response in animals and plants in post-transcriptional gene regulation. Pinewood nematode, Bursaphelenchus xylophilus, is an important invasive plant parasitic nematode in Asia. To have a comprehensive knowledge about miRNAs of the nematode is necessary for further in-depth study on roles of miRNAs in the ecological adaptation of the invasive species. METHODS AND FINDINGS: Five small RNA libraries were constructed and sequenced by Illumina/Solexa deep-sequencing technology. A total of 810 miRNA candidates (49 conserved and 761 novel were predicted by a computational pipeline, of which 57 miRNAs (20 conserved and 37 novel encoded by 53 miRNA precursors were identified by experimental methods. Ten novel miRNAs were considered to be species-specific miRNAs of B. xylophilus. Comparison of expression profiles of miRNAs in the five small RNA libraries showed that many miRNAs exhibited obviously different expression levels in the third-stage dispersal juvenile and at a cold-stressed status. Most of the miRNAs exhibited obviously down-regulated expression in the dispersal stage. But differences among the three geographic libraries were not prominent. A total of 979 genes were predicted to be targets of these authentic miRNAs. Among them, seven heat shock protein genes were targeted by 14 miRNAs, and six FMRFamide-like neuropeptides genes were targeted by 17 miRNAs. A real-time quantitative polymerase chain reaction was used to quantify the mRNA expression levels of target genes. CONCLUSIONS: Basing on the fact that a negative correlation existed between the expression profiles of miRNAs and the mRNA expression profiles of their target genes (hsp, flp by comparing those of the nematodes at a cold stressed status and a normal status, we suggested that miRNAs might participate in ecological adaptation and behavior regulation of the

  5. Distribution and Prevalence of Parasitic Nematodes of Cowpea (Vigna unguiculata) in Burkina Faso.

    Science.gov (United States)

    Sawadogo, A; Thio, B; Kiemde, S; Drabo, I; Dabire, C; Ouedraogo, J; Mullens, T R; Ehlers, J D; Roberts, P A

    2009-06-01

    A comprehensive survey of the plant parasitic nematodes associated with cowpea (Vigna unguiculata) production fields was carried out in the three primary agro-climatic zones of Burkina Faso in West Africa. Across the three zones, a total of 109 samples were collected from the farms of 32 villages to provide a representative coverage of the cowpea production areas. Samples of rhizosphere soil and samples of roots from actively growing cowpea plants were collected during mid- to late-season. Twelve plant-parasitic nematode genera were identified, of which six appeared to have significant parasitic potential on cowpea based on their frequency and abundance. These included Helicotylenchus, Meloidogyne, Pratylenchus, Scutellonema, Telotylenchus, and Tylenchorhynchus. Criconemella and Rotylenchulus also had significant levels of abundance and frequency, respectively. Of the primary genera, Meloidogyne, Pratylenchus, and Scutellonema contained species which are known or suspected to cause losses of cowpea yield in other parts of the world. According to the prevalence and distribution of these genera in Burkina Faso, their potential for damage to cowpea increased from the dry Sahelian semi-desert zone in the north (annual rainfall < 600 mm/year), through the north-central Soudanian zone (annual rainfall of 600-800 mm/year), to the wet Soudanian zone (annual rainfall ≥ 1000 mm) in the more humid south-western region of the country. This distribution trend was particularly apparent for the endoparasitic nematode Meloidogyne and the migratory endoparasite Pratylenchus.

  6. Influence of industrial heavy metal pollution on soil free-living nematode population

    International Nuclear Information System (INIS)

    Pen-Mouratov, Stanislav; Shukurov, Nosir; Steinberger, Yosef

    2008-01-01

    The effect of distance from a heavy metal pollution source on the soil nematode community (trophic structure, sex structure, and taxa composition) was investigated along a 15-km transect originating at the Almalyk Industrial Complex, Uzbekistan (pollution source). The soil nematode community was exposed to heavy metal influence both directly and through soil properties changes. Pollution effect on the density and biomass of soil free-living nematodes was found to be highest at pollution source, with fungivores and plant parasites dominating at the upper and deeper soil layers next to the pollution source. These groups decreased along the transect, yielding domination to bacteria- and fungi-feeders. The sex ratio of nematode communities was found to be dependent on heavy metal pollution levels, with the juveniles being the most sensitive nematode group. The Maturity and modified Maturity Indices, reflecting the degree of disturbance of the soil ecosystem, were found to be the most sensitive indices. - Trophic structure and sex ratio of soil nematode population are sensitive tools for monitoring industrial pollution

  7. Dynamics in the tomato root transcriptome on infection with the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Swiecicka, Magdalena; Filipecki, Marcin; Lont, Dieuwertje; Van Vliet, Joke; Qin, Ling; Goverse, Aska; Bakker, Jaap; Helder, Johannes

    2009-07-01

    Plant parasitic nematodes infect roots and trigger the formation of specialized feeding sites by substantial reprogramming of the developmental process of root cells. In this article, we describe the dynamic changes in the tomato root transcriptome during early interactions with the potato cyst nematode Globodera rostochiensis. Using amplified fragment length polymorphism-based mRNA fingerprinting (cDNA-AFLP), we monitored 17 600 transcript-derived fragments (TDFs) in infected and uninfected tomato roots, 1-14 days after inoculation with nematode larvae. Six hundred and twenty-four TDFs (3.5%) showed significant differential expression on nematode infection. We employed GenEST, a computer program which links gene expression profiles generated by cDNA-AFLP and databases of cDNA sequences, to identify 135 tomato sequences. These sequences were grouped into eight functional categories based on the presence of genes involved in hormone regulation, plant pathogen defence response, cell cycle and cytoskeleton regulation, cell wall modification, cellular signalling, transcriptional regulation, primary metabolism and allocation. The presence of unclassified genes was also taken into consideration. This article describes the responsiveness of numerous tomato genes hitherto uncharacterized during infection with endoparasitic cyst nematodes. The analysis of transcriptome profiles allowed the sequential order of expression to be dissected for many groups of genes and the genes to be connected with the biological processes involved in compatible interactions between the plant and nematode.

  8. Influence of industrial heavy metal pollution on soil free-living nematode population

    Energy Technology Data Exchange (ETDEWEB)

    Pen-Mouratov, Stanislav [The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel); Shukurov, Nosir [Institute of Geology and Geophysics, Academy of Sciences, Tashkent 700041 (Uzbekistan); Steinberger, Yosef [The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel)], E-mail: steinby@mail.biu.ac.il

    2008-03-15

    The effect of distance from a heavy metal pollution source on the soil nematode community (trophic structure, sex structure, and taxa composition) was investigated along a 15-km transect originating at the Almalyk Industrial Complex, Uzbekistan (pollution source). The soil nematode community was exposed to heavy metal influence both directly and through soil properties changes. Pollution effect on the density and biomass of soil free-living nematodes was found to be highest at pollution source, with fungivores and plant parasites dominating at the upper and deeper soil layers next to the pollution source. These groups decreased along the transect, yielding domination to bacteria- and fungi-feeders. The sex ratio of nematode communities was found to be dependent on heavy metal pollution levels, with the juveniles being the most sensitive nematode group. The Maturity and modified Maturity Indices, reflecting the degree of disturbance of the soil ecosystem, were found to be the most sensitive indices. - Trophic structure and sex ratio of soil nematode population are sensitive tools for monitoring industrial pollution.

  9. Interspecific RNA interference of SHOOT MERISTEMLESS-like disrupts Cuscuta pentagona plant parasitism.

    Science.gov (United States)

    Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

    2012-07-01

    Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA-mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection.

  10. Mate Limitation in Fungal Plant Parasites Can Lead to Cyclic Epidemics in Perennial Host Populations.

    Science.gov (United States)

    Ravigné, Virginie; Lemesle, Valérie; Walter, Alicia; Mailleret, Ludovic; Hamelin, Frédéric M

    2017-03-01

    Fungal plant parasites represent a growing concern for biodiversity and food security. Most ascomycete species are capable of producing different types of infectious spores both asexually and sexually. Yet the contributions of both types of spores to epidemiological dynamics have still to been fully researched. Here we studied the effect of mate limitation in parasites which perform both sexual and asexual reproduction in the same host. Since mate limitation implies positive density dependence at low population density, we modeled the dynamics of such species with both density-dependent (sexual) and density-independent (asexual) transmission rates. A first simple SIR model incorporating these two types of transmission from the infected compartment, suggested that combining sexual and asexual spore production can generate persistently cyclic epidemics in a significant part of the parameter space. It was then confirmed that cyclic persistence could occur in realistic situations by parameterizing a more detailed model fitting the biology of the Black Sigatoka disease of banana, for which literature data are available. We discuss the implications of these results for research on and management of Sigatoka diseases of banana.

  11. Anthelmintic resistance in equine nematodes

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    Jacqueline B. Matthews

    2014-12-01

    Full Text Available Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole, tetrahydropyrimidines (pyrantel and macrocyclic lactones (ivermectin, moxidectin. Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantially reduced clinical disease, especially that associated with large strongyle species; however, high treatment frequency has led to considerable selection pressure for anthelmintic resistance, particularly in cyathostomin species. Field studies published over the last decade indicate that benzimidazole resistance is widespread globally in cyathostomins and there are also many reports of resistance to pyrantel in these worms. Cyathostomin resistance to macrocyclic lactone compounds is emerging, principally measured as a reduction in strongyle egg reappearance time observed after treatment. Ivermectin resistance is a further concern in the small intestinal nematode, Parascaris equorum, an important pathogen of foals. These issues indicate that horse nematodes must now be controlled using methods less dependent on anthelmintic use and more reliant on management practices designed to reduce the force of infection in the environment. Such strategies include improved grazing management integrated with targeted anthelmintic administration involving faecal egg count (FEC-directed treatments. The latter require that the supporting diagnostic tests available are robust and practically applicable. Recent research has focused on maximising the value of FEC analysis in horses and on optimizing protocols for anthelmintic efficacy testing. Other studies have sought to develop

  12. A multipartite mitochondrial genome in the potato cyst nematode Globodera pallida.

    Science.gov (United States)

    Armstrong, M R; Blok, V C; Phillips, M S

    2000-01-01

    The mitochondrial genome (mtDNA) of the plant parasitic nematode Globodera pallida exists as a population of small, circular DNAs that, taken individually, are of insufficient length to encode the typical metazoan mitochondrial gene complement. As far as we are aware, this unusual structural organization is unique among higher metazoans, although interesting comparisons can be made with the multipartite mitochondrial genome organizations of plants and fungi. The variation in frequency between populations displayed by some components of the mtDNA is likely to have major implications for the way in which mtDNA can be used in population and evolutionary genetic studies of G. pallida.

  13. The feeding tube of cyst nematodes: characterisation of protein exclusion.

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    Sebastian Eves-van den Akker

    Full Text Available Plant parasitic nematodes comprise several groups; the most economically damaging of these are the sedentary endoparasites. Sedentary endoparasitic nematodes are obligate biotrophs and modify host root tissue, using a suite of effector proteins, to create a feeding site that is their sole source of nutrition. They feed by withdrawing host cell assimilate from the feeding site though a structure known as the feeding tube. The function, composition and molecular characteristics of feeding tubes are poorly characterised. It is hypothesised that the feeding tube facilitates uptake of host cell assimilate by acting as a molecular sieve. Several studies, using molecular mass as the sole indicator of protein size, have given contradictory results about the exclusion limits of the cyst nematode feeding tube. In this study we propose a method to predict protein size, based on protein database coordinates in silico. We tested the validity of these predictions using travelling wave ion mobility spectrometry--mass spectrometry, where predictions and measured values were within approximately 6%. We used the predictions, coupled with mass spectrometry, analytical ultracentrifugation and protein electrophoresis, to resolve previous conflicts and define the exclusion characteristics of the cyst nematode feeding tube. Heterogeneity was tested in the liquid, solid and gas phase to provide a comprehensive evaluation of three proteins of particular interest to feeding tube size exclusion, GFP, mRFP and Dual PI. The data and procedures described here could be applied to the design of plant expressed defence compounds intended for uptake into cyst nematodes. We also highlight the need to assess protein heterogeneity when creating novel fusion proteins.

  14. The feeding tube of cyst nematodes: characterisation of protein exclusion.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J; Ault, James R; Ashcroft, Alison E; Jones, John T; Urwin, Peter E

    2014-01-01

    Plant parasitic nematodes comprise several groups; the most economically damaging of these are the sedentary endoparasites. Sedentary endoparasitic nematodes are obligate biotrophs and modify host root tissue, using a suite of effector proteins, to create a feeding site that is their sole source of nutrition. They feed by withdrawing host cell assimilate from the feeding site though a structure known as the feeding tube. The function, composition and molecular characteristics of feeding tubes are poorly characterised. It is hypothesised that the feeding tube facilitates uptake of host cell assimilate by acting as a molecular sieve. Several studies, using molecular mass as the sole indicator of protein size, have given contradictory results about the exclusion limits of the cyst nematode feeding tube. In this study we propose a method to predict protein size, based on protein database coordinates in silico. We tested the validity of these predictions using travelling wave ion mobility spectrometry--mass spectrometry, where predictions and measured values were within approximately 6%. We used the predictions, coupled with mass spectrometry, analytical ultracentrifugation and protein electrophoresis, to resolve previous conflicts and define the exclusion characteristics of the cyst nematode feeding tube. Heterogeneity was tested in the liquid, solid and gas phase to provide a comprehensive evaluation of three proteins of particular interest to feeding tube size exclusion, GFP, mRFP and Dual PI. The data and procedures described here could be applied to the design of plant expressed defence compounds intended for uptake into cyst nematodes. We also highlight the need to assess protein heterogeneity when creating novel fusion proteins.

  15. Nitrate analogs as attractants for soybean cyst nematode.

    Science.gov (United States)

    Hosoi, Akito; Katsuyama, Tsutomu; Sasaki, Yasuyuki; Kondo, Tatsuhiko; Yajima, Shunsuke; Ito, Shinsaku

    2017-08-01

    Soybean cyst nematode (SCN) Heterodera glycines Ichinohe, a plant parasite, is one of the most serious pests of soybean. In this paper, we report that SCN is attracted to nitrate and its analogs. We performed attraction assays to screen for novel attractants for SCN and found that nitrates were attractants for SCN and SCN recognized nitrate gradients. However, attraction of SCN to nitrates was not observed on agar containing nitrate. To further elucidate the attraction mechanism in SCN, we performed attraction assays using nitrate analogs ([Formula: see text], [Formula: see text], [Formula: see text]). SCN was attracted to all nitrate analogs; however, attraction of SCN to nitrate analogs was not observed on agar containing nitrate. In contrast, SCN was attracted to azuki root, irrespective of presence or absence of nitrate in agar media. Our results suggest that the attraction mechanisms differ between plant-derived attractant and nitrate.

  16. Identification and characterisation of a hyper-variable apoplastic effector gene family of the potato cyst nematodes.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J; Jones, John T; Urwin, Peter E

    2014-09-01

    Sedentary endoparasitic nematodes are obligate biotrophs that modify host root tissues, using a suite of effector proteins to create and maintain a feeding site that is their sole source of nutrition. Using assumptions about the characteristics of genes involved in plant-nematode biotrophic interactions to inform the identification strategy, we provide a description and characterisation of a novel group of hyper-variable extracellular effectors termed HYP, from the potato cyst nematode Globodera pallida. HYP effectors comprise a large gene family, with a modular structure, and have unparalleled diversity between individuals of the same population: no two nematodes tested had the same genetic complement of HYP effectors. Individuals vary in the number, size, and type of effector subfamilies. HYP effectors are expressed throughout the biotrophic stages in large secretory cells associated with the amphids of parasitic stage nematodes as confirmed by in situ hybridisation. The encoded proteins are secreted into the host roots where they are detectable by immunochemistry in the apoplasm, between the anterior end of the nematode and the feeding site. We have identified HYP effectors in three genera of plant parasitic nematodes capable of infecting a broad range of mono- and dicotyledon crop species. In planta RNAi targeted to all members of the effector family causes a reduction in successful parasitism.

  17. Identification and characterisation of a hyper-variable apoplastic effector gene family of the potato cyst nematodes.

    Directory of Open Access Journals (Sweden)

    Sebastian Eves-van den Akker

    2014-09-01

    Full Text Available Sedentary endoparasitic nematodes are obligate biotrophs that modify host root tissues, using a suite of effector proteins to create and maintain a feeding site that is their sole source of nutrition. Using assumptions about the characteristics of genes involved in plant-nematode biotrophic interactions to inform the identification strategy, we provide a description and characterisation of a novel group of hyper-variable extracellular effectors termed HYP, from the potato cyst nematode Globodera pallida. HYP effectors comprise a large gene family, with a modular structure, and have unparalleled diversity between individuals of the same population: no two nematodes tested had the same genetic complement of HYP effectors. Individuals vary in the number, size, and type of effector subfamilies. HYP effectors are expressed throughout the biotrophic stages in large secretory cells associated with the amphids of parasitic stage nematodes as confirmed by in situ hybridisation. The encoded proteins are secreted into the host roots where they are detectable by immunochemistry in the apoplasm, between the anterior end of the nematode and the feeding site. We have identified HYP effectors in three genera of plant parasitic nematodes capable of infecting a broad range of mono- and dicotyledon crop species. In planta RNAi targeted to all members of the effector family causes a reduction in successful parasitism.

  18. The effect of linalool on second-stage juveniles of the potato cyst nematodes Globodera rostochiensis and G. pallida.

    Science.gov (United States)

    Būda, Vincas; Cepulytė-Rakauskienė, Rasa

    2011-09-01

    Linalool is either a toxic compound to a few species of plant parasitic nematodes or attractive to entomopathogenic nematodes. This compound is produced and emitted by several host plants of Globodera rostochiensis and G. pallida, the potato cyst nematodes (PCN). With the aim to reveal the effect of linalool on PCN, laboratory assays were carried out. Survival of PCN second-stage juveniles (J2s) in water + linalool control did not differ; thus, proving linalool to be nontoxic to PCN. Behavioral assays carried out in Petri dishes revealed attractiveness in the form of positive response of J2s of both PCN species towards linalool. Based on these behavioral assays, sensitivity to linalool of G. rostochiensis J2s was higher compared with that of G. pallida J2s. Linalool is the first compound of plant origin to elicit positive response in both PCN species.

  19. Identification of novel target genes for safer and more specific control of root-knot nematodes from a pan-genome mining.

    Directory of Open Access Journals (Sweden)

    Etienne G J Danchin

    2013-10-01

    Full Text Available Root-knot nematodes are globally the most aggressive and damaging plant-parasitic nematodes. Chemical nematicides have so far constituted the most efficient control measures against these agricultural pests. Because of their toxicity for the environment and danger for human health, these nematicides have now been banned from use. Consequently, new and more specific control means, safe for the environment and human health, are urgently needed to avoid worldwide proliferation of these devastating plant-parasites. Mining the genomes of root-knot nematodes through an evolutionary and comparative genomics approach, we identified and analyzed 15,952 nematode genes conserved in genomes of plant-damaging species but absent from non target genomes of chordates, plants, annelids, insect pollinators and mollusks. Functional annotation of the corresponding proteins revealed a relative abundance of putative transcription factors in this parasite-specific set compared to whole proteomes of root-knot nematodes. This may point to important and specific regulators of genes involved in parasitism. Because these nematodes are known to secrete effector proteins in planta, essential for parasitism, we searched and identified 993 such effector-like proteins absent from non-target species. Aiming at identifying novel targets for the development of future control methods, we biologically tested the effect of inactivation of the corresponding genes through RNA interference. A total of 15 novel effector-like proteins and one putative transcription factor compatible with the design of siRNAs were present as non-redundant genes and had transcriptional support in the model root-knot nematode Meloidogyne incognita. Infestation assays with siRNA-treated M. incognita on tomato plants showed significant and reproducible reduction of the infestation for 12 of the 16 tested genes compared to control nematodes. These 12 novel genes, showing efficient reduction of parasitism when

  20. Enhanced resistance to soybean cyst nematode Heterodera glycines in transgenic soybean by silencing putative CLE receptors.

    Science.gov (United States)

    Guo, Xiaoli; Chronis, Demosthenis; De La Torre, Carola M; Smeda, John; Wang, Xiaohong; Mitchum, Melissa G

    2015-08-01

    CLE peptides are small extracellular proteins important in regulating plant meristematic activity through the CLE-receptor kinase-WOX signalling module. Stem cell pools in the SAM (shoot apical meristem), RAM (root apical meristem) and vascular cambium are controlled by CLE signalling pathways. Interestingly, plant-parasitic cyst nematodes secrete CLE-like effector proteins, which act as ligand mimics of plant CLE peptides and are required for successful parasitism. Recently, we demonstrated that Arabidopsis CLE receptors CLAVATA1 (CLV1), the CLAVATA2 (CLV2)/CORYNE (CRN) heterodimer receptor complex and RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2), which transmit the CLV3 signal in the SAM, are required for perception of beet cyst nematode Heterodera schachtii CLEs. Reduction in nematode infection was observed in clv1, clv2, crn, rpk2 and combined double and triple mutants. In an effort to develop nematode resistance in an agriculturally important crop, orthologues of Arabidopsis receptors including CLV1, CLV2, CRN and RPK2 were identified from soybean, a host for the soybean cyst nematode Heterodera glycines. For each of the receptors, there are at least two paralogues in the soybean genome. Localization studies showed that most receptors are expressed in the root, but vary in their level of expression and spatial expression patterns. Expression in nematode-induced feeding cells was also confirmed. In vitro direct binding of the soybean receptors with the HgCLE peptide was analysed. Knock-down of the receptors in soybean hairy roots showed enhanced resistance to SCN. Our findings suggest that targeted disruption of nematode CLE signalling may be a potential means to engineer nematode resistance in crop plants. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  1. Nematodes Relevance in Soil Quality Management and their Significance as Biomarkers in Aquatic Substrates: Review.

    Science.gov (United States)

    Akpheokhai, Leonard I; Oribhabor, Blessing J

    2016-01-01

    The interaction of man with the ecosystem is a major factor causing environmental pollution and its attendant consequences such as climate change in our world today. Patents relating to nematodes' relevance in soil quality management and their significance as biomarkers in aquatic substrates were reviewed. Nematodes are useful in rapid, easy and inexpensive method for testing the toxicity of substance (e.g. aquatic substrates). This review paper sets out to examine and discuss the issue of soil pollution, functions of nematodes in soil and aquatic substrates as well as bio-indicators in soil health management in terrestrial ecology. The information used were on the basis of secondary sources from previous research. It is abundantly clear that the population dynamics of plant parasitic or free-living nematodes have useful potentials as biomonitor for soil health and other forms of environmental contamination through agricultural activities, industrial pollution and oil spillage, and the analysis of nematode community structure could be used as complementary information obtained from conventional soil testing approaches.

  2. Phloem development in nematode-induced feeding sites: The implications of auxin and cytokinin

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    Birgit eAbsmanner

    2013-07-01

    Full Text Available Sedentary plant parasitic nematodes such as root-knot nematodes and cyst nematodes induce giant cells or syncytia, respectively, in their host plant’s roots. These highly specialized structures serve as feeding sites from which exclusively the nematodes withdraw nutrients. While giant cells are symplastically isolated and obtain assimilates by transporter-mediated processes syncytia are massively connected to the phloem by plasmodesmata. To support the feeding sites and the nematode during their development, phloem is induced around syncytia and giant cells. In the case of syncytia the unloading phloem consists of sieve elements and companion cells and in the case of root knots it consists exclusively of sieve elements. We applied immunohistochemistry to identify the cells within the developing phloem that responded to auxin and cytokinin. Both feeding sites themselves did not respond to either hormone. We were able to show that in root knots an auxin response precedes the differentiation of these auxin responsive cells into phloem elements. This process appears to be independent of B-type Arabidopsis response regulators. Using additional markers for tissue identity we provide evidence that around giant cells protophloem is formed and proliferates dramatically. In contrast, the phloem around syncytia responded to both hormones. The presence of companion cells as well as hormone-responsive sieve elements suggests that metaphloem development occurs. The implication of auxin and cytokinin in the further development of the metaphloem is discussed.

  3. Effect of tillage and crop residue management on nematode densities on corn.

    Science.gov (United States)

    McSorley, R; Gallaher, R N

    1994-12-01

    Effects of winter cover crop management on nematode densities associated with a subsequent corn (Zea mays) crop were examined in five sites in north Florida. Two sites had received winter cover crops of lupine (Lupinus angustifolius), and one site each had rye (Secale cereale), hairy vetch (Vicia villosa), and crimson clover (Trifolium incarnatum). In each site, five different management regimes were compared: 1) conventional tillage after the cover crop was removed for forage; 2) conventional tillage with the cover crop retained as green manure; 3) no-till with the cover crop mowed and used as a mulch; 4) no-till with the cover crop removed as forage; and 5) fallow. Sites were sampled at corn planting and harvest for estimates of initial (Pi) and final (Pf) nematode population densities, respectively. Whether the cover crop was removed as forage or retained as green manure or mulch had no effect (P > 0.10) on population densities of any plant-parasitic nematode before or after corn at any site. Differences between conventional-till and no-till treatments were significant (P cover crop residues had little consistent effect on nematodes, and these practices should be considered based on agronomic benefits rather than for nematode management.

  4. 1,10-Phenanthroline and its derivatives are novel hatching stimulants for soybean cyst nematodes.

    Science.gov (United States)

    Nonaka, Shiori; Katsuyama, Tsutomu; Kondo, Tatsuhiko; Sasaki, Yasuyuki; Asami, Tadao; Yajima, Shunsuke; Ito, Shinsaku

    2016-11-01

    Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a plant-parasitic nematode and one of the most serious soybean pests. Herein, we present the heterocyclic compound 1,10-phenanthroline (Phen) and its derivatives as novel hatching stimulants for SCN. Phen treatment promoted hatching of second-stage juveniles of SCNs in a concentration-dependent manner. In addition, the hatching of SCNs following treatment with Phen occurred more rapidly than that following treatment with the known hatching stimulant, glycinoeclepin A (GEA). Furthermore, the co-application of Phen and GEA enhanced SCN hatching rate compared with that of Phen or GEA alone. A structure-activity relationship study for Phen derivatives suggested that 2,2'-bipyridine is the essential structure of the SCN-hatching stimulants. These results suggest that Phen and its derivatives activate different hatching pathways of SCNs from GEA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Isolation of Antagonistic Endophytes from Banana Roots against Meloidogyne javanica and Their Effects on Soil Nematode Community

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    Lanxi Su

    2017-10-01

    Full Text Available Banana production is seriously hindered by Meloidogyne spp. all over the world. Endophytes are ideal candidates compared to pesticides as an environmentally benign agent. In the present study, endophytes isolated from banana roots infected by Meloidogyne spp. with different disease levels were tested in vitro, and in sterile and nature banana monoculture soils against Meloidogyne javanica. The proportion of antagonistic endophytes were higher in the roots of middle and high disease levels. Among those, bacteria were dominant, and Pseudomonas spp., Bacillus spp. and Streptomyces spp. showed more abundant populations. One strain, named as SA, with definite root inner-colonization ability was isolated and identified as Streptomyces sp. This strain showed an inhibiting rate of >50% in vitro and biocontrol efficiency of 70.7% in sterile soil against Meloidogyne javanica, compared to the control. Greenhouse experiment results showed that the strain SA exhibits excellent biological control ability for plant-parasites both in roots and in root-knot nematode infested soil. SA treatment showed a higher number of bacterivores, especially Mesorhabditis and Cephalobus. The maturity index was significantly lower, while enrichment index (EI was significantly higher in the SA treatment. In conclusion, this study presents an important potential application of the endophytic strain Streptomyces sp. for the control of plant-parasitic nematodes, especially Meloidogyne javanica, and presents the effects on the associated variation of the nematode community.

  6. Study of Enhanced Radiation Impact on the Resistance of Plant - Parasite System

    International Nuclear Information System (INIS)

    Damianova, A.; Sivriev, I.; Baicheva, O.; Ivanova, I

    2004-01-01

    The paper aimed to report the results from the experiments carried out in order to investigate the dependence between the increasing radiation doses and the vitality and reproductivity of the wide spread in the natural and agroecosystems nematodes Meloidogyne arenaria used as a laboratory model. In this study the influence of different doses of α- and γ- radiation have been examined using isotopes of 241 Am and 60 Co. As a result of the performed experiments a conclusion could be made for the protective role of the glycoproteid structures of the parasite sac against α-radiation. Part of the effects observed probably are due to the development in the process of evolution of a protective mechanism in order to adapt the organisms to the modifying of the radiation background

  7. Management of Root-Nematode (Meloidogyne SPP)

    International Nuclear Information System (INIS)

    Miano, D.W

    2002-01-01

    Greenhouse and field experiments were undertaken to determine the possibility of using soil amendments with different C:N levels or applied at different rates and times in the control of root-knot nematodes (Meloidogyne spp.)in tomato c.v Cal J.A naturally infested field was used while artificial inoculation was done in the greenhouse. Root galling was rated on a scale of 0-10, nematode population was estimated by counting second stage juveniles extracted from 200 cm 3 soil and fruit yields were recorded at the end of the season. Nematode population densities and galling indices were significantly (P< or=0.05) lower in amended soils compared to the control. Application of the amendments also resulted in significant (P< or=0.05) increase in yields. Chicken manure, compost manure, neem products and pig manure were were the most effective amendments. Fresh chicken manure had a more suppressive effect on nematode than when the manure was decomposed within or outside a nematode infested field. A general decrease in juvenile populations and galling was observed with increase of organic amendments applied

  8. A distinct role of pectate lyases in the formation of feeding structures induced by cyst and root-knot nematodes.

    Science.gov (United States)

    Wieczorek, K; Elashry, A; Quentin, M; Grundler, F M W; Favery, B; Seifert, G J; Bohlmann, H

    2014-09-01

    Pectin in the primary plant cell wall is thought to be responsible for its porosity, charge density, and microfibril spacing and is the main component of the middle lamella. Plant-parasitic nematodes secrete cell wall-degrading enzymes that macerate the plant tissue, facilitating the penetration and migration within the roots. In sedentary endoparasitic nematodes, these enzymes are released only during the migration of infective juveniles through the root. Later, nematodes manipulate the expression of host plant genes, including various cell wall enzymes, in order to induce specific feeding sites. In this study, we investigated expression of two Arabidopsis pectate lyase-like genes (PLL), PLL18 (At3g27400) and PLL19 (At4g24780), together with pectic epitopes with different degrees of methylesterification in both syncytia induced by the cyst nematode Heterodera schachtii and giant cells induced by the root-knot nematode Meloidogyne incognita. We confirmed upregulation of PLL18 and PLL19 in both types of feeding sites with quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) and in situ RT-PCR. Furthermore, the functional analysis of mutants demonstrated the important role of both PLL genes in the development and maintenance of syncytia but not giant cells. Our results show that both enzymes play distinct roles in different infected root tissues as well as during parasitism of different nematodes.

  9. Rather than by direct acquisition via lateral gene transfer, GHF5 cellulases were passed on from early Pratylenchidae to root-knot and cyst nematodes.

    Science.gov (United States)

    Rybarczyk-Mydłowska, Katarzyna; Maboreke, Hazel Ruvimbo; van Megen, Hanny; van den Elsen, Sven; Mooyman, Paul; Smant, Geert; Bakker, Jaap; Helder, Johannes

    2012-11-21

    Plant parasitic nematodes are unusual Metazoans as they are equipped with genes that allow for symbiont-independent degradation of plant cell walls. Among the cell wall-degrading enzymes, glycoside hydrolase family 5 (GHF5) cellulases are relatively well characterized, especially for high impact parasites such as root-knot and cyst nematodes. Interestingly, ancestors of extant nematodes most likely acquired these GHF5 cellulases from a prokaryote donor by one or multiple lateral gene transfer events. To obtain insight into the origin of GHF5 cellulases among evolutionary advanced members of the order Tylenchida, cellulase biodiversity data from less distal family members were collected and analyzed. Single nematodes were used to obtain (partial) genomic sequences of cellulases from representatives of the genera Meloidogyne, Pratylenchus, Hirschmanniella and Globodera. Combined Bayesian analysis of ≈ 100 cellulase sequences revealed three types of catalytic domains (A, B, and C). Represented by 84 sequences, type B is numerically dominant, and the overall topology of the catalytic domain type shows remarkable resemblance with trees based on neutral (= pathogenicity-unrelated) small subunit ribosomal DNA sequences. Bayesian analysis further suggested a sister relationship between the lesion nematode Pratylenchus thornei and all type B cellulases from root-knot nematodes. Yet, the relationship between the three catalytic domain types remained unclear. Superposition of intron data onto the cellulase tree suggests that types B and C are related, and together distinct from type A that is characterized by two unique introns. All Tylenchida members investigated here harbored one or multiple GHF5 cellulases. Three types of catalytic domains are distinguished, and the presence of at least two types is relatively common among plant parasitic Tylenchida. Analysis of coding sequences of cellulases suggests that root-knot and cyst nematodes did not acquire this gene directly

  10. Rather than by direct acquisition via lateral gene transfer, GHF5 cellulases were passed on from early Pratylenchidae to root-knot and cyst nematodes

    Directory of Open Access Journals (Sweden)

    Rybarczyk-Mydłowska Katarzyna

    2012-11-01

    Full Text Available Abstract Background Plant parasitic nematodes are unusual Metazoans as they are equipped with genes that allow for symbiont-independent degradation of plant cell walls. Among the cell wall-degrading enzymes, glycoside hydrolase family 5 (GHF5 cellulases are relatively well characterized, especially for high impact parasites such as root-knot and cyst nematodes. Interestingly, ancestors of extant nematodes most likely acquired these GHF5 cellulases from a prokaryote donor by one or multiple lateral gene transfer events. To obtain insight into the origin of GHF5 cellulases among evolutionary advanced members of the order Tylenchida, cellulase biodiversity data from less distal family members were collected and analyzed. Results Single nematodes were used to obtain (partial genomic sequences of cellulases from representatives of the genera Meloidogyne, Pratylenchus, Hirschmanniella and Globodera. Combined Bayesian analysis of ≈ 100 cellulase sequences revealed three types of catalytic domains (A, B, and C. Represented by 84 sequences, type B is numerically dominant, and the overall topology of the catalytic domain type shows remarkable resemblance with trees based on neutral (= pathogenicity-unrelated small subunit ribosomal DNA sequences. Bayesian analysis further suggested a sister relationship between the lesion nematode Pratylenchus thornei and all type B cellulases from root-knot nematodes. Yet, the relationship between the three catalytic domain types remained unclear. Superposition of intron data onto the cellulase tree suggests that types B and C are related, and together distinct from type A that is characterized by two unique introns. Conclusions All Tylenchida members investigated here harbored one or multiple GHF5 cellulases. Three types of catalytic domains are distinguished, and the presence of at least two types is relatively common among plant parasitic Tylenchida. Analysis of coding sequences of cellulases suggests that root

  11. Nematode-Trapping Fungi.

    Science.gov (United States)

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

    Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

  12. Nematode pests threatening soybean production in South Africa, with reference to Meloidogyne

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    Hendrika Fourie

    2015-09-01

    Full Text Available The area planted to soybean in South Africa has increased by 54% since the 2009 growing season, mainly as a result of the increasing demand for protein-rich food and fodder sources. Moreover, the introduction of advanced technology, namely the availability of genetically modified herbicide tolerant soybean cultivars also contributed towards increased soybean production. The omnipresence of plant-parasitic nematodes in local agricultural soils, however, poses a threat to the sustainable expansion and production of soybean and other rotation crops. Meloidogyne incognita and M. javanica are the predominant nematode pests in local soybean production areas and those where other grain-, legume- and/or vegetable crops are grown. The lack of registered nematicides for soybean locally, crop production systems that are conducive to nematode pest build-ups as well as the limited availability of genetic host plant resistance to root-knot nematode pests, complicate their management. Research aimed at various aspects related to soybean-nematode research, namely, audits of nematode assemblages associated with the crop, identification of genetic host plant resistance in soybean germplasm to M. incognita and M. javanica, the use of molecular markers that are linked to such genetic resistance traits as well as agronomic performance of pre-released cultivars that can be valuable to producers and the industry are accentuated in this review. Evaluation of synthetically-derived as well as biological-control agents are also discussed as complementary management tactics. It is important that lessons learned through extensive research on soybean-nematode interactions in South Africa be shared with researchers and industries in other countries as they might experience or expect similar problems and/or challenges.

  13. Transcriptome analysis of resistant and susceptible alfalfa cultivars infected with root-knot nematode Meloidogyne incognita.

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    Olga A Postnikova

    Full Text Available Nematodes are one of the major limiting factors in alfalfa production. Root-knot nematodes (RKN, Meloidogyne spp. are widely distributed and economically important sedentary endoparasites of agricultural crops and they may inflict significant damage to alfalfa fields. As of today, no studies have been published on global gene expression profiling in alfalfa infected with RKN or any other plant parasitic nematode. Very little information is available about molecular mechanisms that contribute to pathogenesis and defense responses in alfalfa against these pests and specifically against RKN. In this work, we performed root transcriptome analysis of resistant (cv. Moapa 69 and susceptible (cv. Lahontan alfalfa cultivars infected with RKN Meloidogyne incognita, widespread root-knot nematode species and a major pest worldwide. A total of 1,701,622,580 pair-end reads were generated on an Illumina Hi-Seq 2000 platform from the roots of both cultivars and assembled into 45,595 and 47,590 transcripts in cvs Moapa 69 and Lahontan, respectively. Bioinformatic analysis revealed a number of common and unique genes that were differentially expressed in susceptible and resistant lines as a result of nematode infection. Although the susceptible cultivar showed a more pronounced defense response to the infection, feeding sites were successfully established in its roots. Characteristically, basal gene expression levels under normal conditions differed between the two cultivars as well, which may confer advantage to one of the genotypes toward resistance to nematodes. Differentially expressed genes were subsequently assigned to known Gene Ontology categories to predict their functional roles and associated biological processes. Real-time PCR validated expression changes in genes arbitrarily selected for experimental confirmation. Candidate genes that contribute to protection against M. incognita in alfalfa were proposed and alfalfa-nematode interactions with

  14. INFLUENCE OF LAND USE AND SOIL MANAGEMENT PRACTICES ON THE OCCURRENCE OF NEMATODE DESTROYING FUNGI IN TAITA TAVETA, KENYA

    Directory of Open Access Journals (Sweden)

    Peter M. Wachira

    2009-02-01

    Full Text Available Due to the increased concerns about the effect of agro-chemicals on soil health and soil biodiversity, use of biological methods has become most acceptable alternative methods for farmers to control soil pathogens during crop production. A study was therefore undertaken to determine the occurrence of nematode destroying fungi in Taita Taveta with the aim of isolating and characterizing them for biological control of plant parasitic nematodes. Twenty eight fungal isolates, distributed in three genera, were identified as nematode destroying fungi from all the positive soil samples. Out of the isolates that were identified, 71, 25 and 4 % were in the genera Arthrobotrys, Monacrosporium and Nematoctonus respectively. Arthrobotrys oligospora had an occurrence frequency of 42.9% which was the highest followed by A. dactyloides, M.cionopagum, Monacrosporium sp and Nematoctonus sp with frequencies of 28.6, 17.9 and 7.1and 3.6% respectively. The occurrence of nematode destroying fungi was affected by land use and organic inputs (P ≤ 0.05 while it was not affected by crop rotation (P ≥ 0.05. Napier land use was more diverse than the other land uses with a mean shannon diversity index of 0.717 followed by horticulture (index 0.497. Maize /bean, coffee/beans, fallow and shrub land uses had a mean shannon index of 0. The same trend was observed on richness where napier had a mean richness of 2.2, horticulture 1.8, maize bean 1 while shrub, fallow and coffee/ beans all had mean richness of 0.2. A.oligospora was the most frequently isolated fungi (42.9 % and showed high potential in biocontrol of plant-parasitic nematodes and was recommended for further studies and development as a biological control agent.

  15. Sugarcane straw and the populations of pests and nematodes

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    Leila Luci Dinardo-Miranda

    2013-10-01

    Full Text Available The green cane harvesting represented a significant change in sugarcane ecosystem due to the presence of straw left on the soil and to the absence of fire. These two factors may affect the populations of pests and their natural enemies. Among the pests benefit from the green cane harvesting stand out the spittlebug, Mahanarva fimbriolata, the curculionid Sphenophorus levis and sugarcane borer, Diatraea saccharalis. In areas of green cane harvesting, the population of these species grew faster than in areas of burnt cane. On the other hand, there are virtually no records of attacks by lesser cornstalk borers in areas of green cane harvesting. Populations of plant parasitic nematodes and the beetles Migdolus fryanus, very important pests of sugarcane, were apparently not affected by the green cane harvesting. Despite the absence of more consistent information, it appears that populations of ants and the giant borer Telchin licus can increase in green cane areas, due primarily to the difficulty of pest control. The partial or total removal of straw from the field represents an additional change to the ecosystem that could alter the status of pests and nematodes. It is likely that spittlebug, the curculionid S. levis and sugarcane borer populations decrease if a portion of the straw is removed from the field. However, the pest populations in areas where the straw is collected will not return to their original conditions at the time of burnt cane harvesting because the absence of fire will be maintained.

  16. Inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (Meloidogyne spp.) as revealed by a bacterial parasite (Pasteuria penetrans).

    Science.gov (United States)

    Davies, K G; Rowe, J A; Williamson, V M

    2008-06-01

    Specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the Gram-positive bacterial hyperparasite Pasteuria penetrans. This bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. Endospore attachment of P. penetrans populations to second-stage juveniles of the root-knot nematode species Meloidogyne incognita and Meloidogyne hapla showed there were interactive differences between bacterial populations and nematode species. Infected females of M. incognita produced a few progeny which were used to establish two nematode lines from single infective juveniles encumbered with either three or 26 endospores. Single juvenile descent lines of each nematode species were produced to test whether cuticle variation was greater within M. hapla lines that reproduce by facultative meiotic parthenogenesis than within lines of M. incognita, which reproduces by obligate parthenogenesis. Assays revealed variability between broods of individual females derived from single second-stage juvenile descent lines of both M. incognita and M. hapla suggesting that progeny derived from a single individual can differ in spore adhesion in both sexual and asexual nematode species. These results suggest that special mechanisms that produced these functional differences in the cuticle surface may have evolved in both sexually and asexually reproducing nematodes as a strategy to circumvent infection by this specialised hyperparasite.

  17. Sequence mining and transcript profiling to explore cyst nematode parasitism

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    Recknor Justin

    2009-01-01

    Full Text Available Abstract Background Cyst nematodes are devastating plant parasites that become sedentary within plant roots and induce the transformation of normal plant cells into elaborate feeding cells with the help of secreted effectors, the parasitism proteins. These proteins are the translation products of parasitism genes and are secreted molecular tools that allow cyst nematodes to infect plants. Results We present here the expression patterns of all previously described parasitism genes of the soybean cyst nematode, Heterodera glycines, in all major life stages except the adult male. These insights were gained by analyzing our gene expression dataset from experiments using the Affymetrix Soybean Genome Array GeneChip, which contains probeset sequences for 6,860 genes derived from preparasitic and parasitic H. glycines life stages. Targeting the identification of additional H. glycines parasitism-associated genes, we isolated 633 genes encoding secretory proteins using algorithms to predict secretory signal peptides. Furthermore, because some of the known H. glycines parasitism proteins have strongest similarity to proteins of plants and microbes, we searched for predicted protein sequences that showed their highest similarities to plant or microbial proteins and identified 156 H. glycines genes, some of which also contained a signal peptide. Analyses of the expression profiles of these genes allowed the formulation of hypotheses about potential roles in parasitism. This is the first study combining sequence analyses of a substantial EST dataset with microarray expression data of all major life stages (except adult males for the identification and characterization of putative parasitism-associated proteins in any parasitic nematode. Conclusion We have established an expression atlas for all known H. glycines parasitism genes. Furthermore, in an effort to identify additional H. glycines genes with putative functions in parasitism, we have reduced the

  18. Soil Nematode Response to Biochar Addition in a Chinese Wheat Field

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-Ke; LI Qi; LIANG Wen-Ju; ZHANG Min; BAO Xue-Lian; XIE Zu-Bin

    2013-01-01

    While studies have focused on the use of biochar as soil amendment,little attention has been paid to its effect on soil fauna.The biochar was produced from slow pyrolysis of wheat straw in the present study.Four treatments,no addition (CK) and three rates of biochar addition at 2400 (B1),12000 (B5) and 48000 kg ha-1 (B20),were investigated to assess the effect of biochar addition to soil on nematode abundance and diversity in a microcosm trial in China.The B5 and B20 application significantly increased the total organic carbon and the C/N ratio.No significant difference in total nematode abundance was found among the treatments.The biochar addition to the soil significantly increased the abundance of fungivores,and decreased that of plant parasites.The diversity of soil nematodes was significantly increased by B1 compared to CK.Nematode trophic groups were more effectively indicative to biochar addition than total abundance.

  19. Origin, distribution and 3D-modeling of Gr-EXPB1, an expansin from the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Kudla, Urszula; Qin, Ling; Milac, Adina; Kielak, Anna; Maissen, Cyril; Overmars, Hein; Popeijus, Herman; Roze, Erwin; Petrescu, Andrei; Smant, Geert; Bakker, Jaap; Helder, Johannes

    2005-04-25

    Southern analysis showed that Gr-EXPB1, a functional expansin from the potato cyst nematode Globodera rostochiensis, is member of a multigene family, and EST data suggest expansins to be present in other plant parasitic nematodes as well. Homology modeling predicted that Gr-EXPB1 domain 1 (D1) has a flat beta-barrel structure with surface-exposed aromatic rings, whereas the 3D structure of Gr-EXPB1-D2 was remarkably similar to plant expansins. Gr-EXPB1 shows highest sequence similarity to two extracellular proteins from saprophytic soil-inhabiting Actinobacteria, and includes a bacterial type II carbohydrate-binding module. These results support the hypothesis that a number of pathogenicity factors of cyst nematodes is of procaryotic origin and were acquired by horizontal gene transfer.

  20. Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

    Science.gov (United States)

    Ramirez, Ricardo A; Spears, Lori R

    2014-10-01

    Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

  1. De novo assembly and characterization of the transcriptome of the parasitic weed dodder identifies genes associated with plant parasitism.

    Science.gov (United States)

    Ranjan, Aashish; Ichihashi, Yasunori; Farhi, Moran; Zumstein, Kristina; Townsley, Brad; David-Schwartz, Rakefet; Sinha, Neelima R

    2014-11-01

    Parasitic flowering plants are one of the most destructive agricultural pests and have major impact on crop yields throughout the world. Being dependent on finding a host plant for growth, parasitic plants penetrate their host using specialized organs called haustoria. Haustoria establish vascular connections with the host, which enable the parasite to steal nutrients and water. The underlying molecular and developmental basis of parasitism by plants is largely unknown. In order to investigate the process of parasitism, RNAs from different stages (i.e. seed, seedling, vegetative strand, prehaustoria, haustoria, and flower) were used to de novo assemble and annotate the transcriptome of the obligate plant stem parasite dodder (Cuscuta pentagona). The assembled transcriptome was used to dissect transcriptional dynamics during dodder development and parasitism and identified key gene categories involved in the process of plant parasitism. Host plant infection is accompanied by increased expression of parasite genes underlying transport and transporter categories, response to stress and stimuli, as well as genes encoding enzymes involved in cell wall modifications. By contrast, expression of photosynthetic genes is decreased in the dodder infective stages compared with normal stem. In addition, genes relating to biosynthesis, transport, and response of phytohormones, such as auxin, gibberellins, and strigolactone, were differentially expressed in the dodder infective stages compared with stems and seedlings. This analysis sheds light on the transcriptional changes that accompany plant parasitism and will aid in identifying potential gene targets for use in controlling the infestation of crops by parasitic weeds. © 2014 American Society of Plant Biologists. All Rights Reserved.

  2. De novo transcriptome sequencing and analysis of the cereal cyst nematode, Heterodera avenae.

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar

    Full Text Available The cereal cyst nematode (CCN, Heterodera avenae is a major pest of wheat (Triticum spp that reduces crop yields in many countries. Cyst nematodes are obligate sedentary endoparasites that reproduce by amphimixis. Here, we report the first transcriptome analysis of two stages of H. avenae. After sequencing extracted RNA from pre parasitic infective juvenile and adult stages of the life cycle, 131 million Illumina high quality paired end reads were obtained which generated 27,765 contigs with N50 of 1,028 base pairs, of which 10,452 were annotated. Comparative analyses were undertaken to evaluate H. avenae sequences with those of other plant, animal and free living nematodes to identify differences in expressed genes. There were 4,431 transcripts common to H. avenae and the free living nematode Caenorhabditis elegans, and 9,462 in common with more closely related potato cyst nematode, Globodera pallida. Annotation of H. avenae carbohydrate active enzymes (CAZy revealed fewer glycoside hydrolases (GHs but more glycosyl transferases (GTs and carbohydrate esterases (CEs when compared to M. incognita. 1,280 transcripts were found to have secretory signature, presence of signal peptide and absence of transmembrane. In a comparison of genes expressed in the pre-parasitic juvenile and feeding female stages, expression levels of 30 genes with high RPKM (reads per base per kilo million value, were analysed by qRT-PCR which confirmed the observed differences in their levels of expression levels. In addition, we have also developed a user-friendly resource, Heterodera transcriptome database (HATdb for public access of the data generated in this study. The new data provided on the transcriptome of H. avenae adds to the genetic resources available to study plant parasitic nematodes and provides an opportunity to seek new effectors that are specifically involved in the H. avenae-cereal host interaction.

  3. De novo transcriptome sequencing and analysis of the cereal cyst nematode, Heterodera avenae.

    Science.gov (United States)

    Kumar, Mukesh; Gantasala, Nagavara Prasad; Roychowdhury, Tanmoy; Thakur, Prasoon Kumar; Banakar, Prakash; Shukla, Rohit N; Jones, Michael G K; Rao, Uma

    2014-01-01

    The cereal cyst nematode (CCN, Heterodera avenae) is a major pest of wheat (Triticum spp) that reduces crop yields in many countries. Cyst nematodes are obligate sedentary endoparasites that reproduce by amphimixis. Here, we report the first transcriptome analysis of two stages of H. avenae. After sequencing extracted RNA from pre parasitic infective juvenile and adult stages of the life cycle, 131 million Illumina high quality paired end reads were obtained which generated 27,765 contigs with N50 of 1,028 base pairs, of which 10,452 were annotated. Comparative analyses were undertaken to evaluate H. avenae sequences with those of other plant, animal and free living nematodes to identify differences in expressed genes. There were 4,431 transcripts common to H. avenae and the free living nematode Caenorhabditis elegans, and 9,462 in common with more closely related potato cyst nematode, Globodera pallida. Annotation of H. avenae carbohydrate active enzymes (CAZy) revealed fewer glycoside hydrolases (GHs) but more glycosyl transferases (GTs) and carbohydrate esterases (CEs) when compared to M. incognita. 1,280 transcripts were found to have secretory signature, presence of signal peptide and absence of transmembrane. In a comparison of genes expressed in the pre-parasitic juvenile and feeding female stages, expression levels of 30 genes with high RPKM (reads per base per kilo million) value, were analysed by qRT-PCR which confirmed the observed differences in their levels of expression levels. In addition, we have also developed a user-friendly resource, Heterodera transcriptome database (HATdb) for public access of the data generated in this study. The new data provided on the transcriptome of H. avenae adds to the genetic resources available to study plant parasitic nematodes and provides an opportunity to seek new effectors that are specifically involved in the H. avenae-cereal host interaction.

  4. Response of Pinus ponderosa Seedlings to Stylet-Bearing Nematodes

    Science.gov (United States)

    Viglierchio, D. R.

    1979-01-01

    Of 12 stylet-bearing nematodes used for inoculations, Pratylenchus penetrans, P. brachyurus, P. vulnus, Ditylenchus destructor, Meloidogyne incognita, M. javanica, and M. hapla reproduced on Pinus ponderosa, while Xiphinema index, Aphelenchus avenae, Paratylenehus neoamblycephalus, Tylenchulus semipenetrans, and Macroposthonia xenoplax did not. P. vulnus, P. brachyurus, P. penetrans, A. avenae, D. destructor, T. semipenetrans, and P. neoamblycephalus significantly suppressed both the shoot and root wet weights of ponderosa pine seedlings obtained from stands in five different locations. X. index significantly suppressed root wet weights, M. xenoplax siguificantly suppressed shoot wet weight, and M. incognita, M. javanica, and M. hapla suppressed neither at the inoculation levels used. Injurious nematodes tended to suppress root growth more than shoot growth. Seedlings from two locations produced greater shoot growth wet weight than did seedlings from the other three locations. The more injurious nematodes tended to cause an increase in the water content of shoots. Frequency analyses of seedling population shoot-root ratios indicated that ponderosa pine seedlings could be selected for better shoot-root ratios as well as for resistance to several pathogenic nematodes. PMID:19300659

  5. Genome-wide association study uncovers a novel QTL allele of AtS40-3 that affects the sex ratio of cyst nematodes in Arabidopsis.

    Science.gov (United States)

    Anwer, Muhammad Arslan; Anjam, Muhammad Shahzad; Shah, Syed Jehangir; Hasan, M Shamim; Naz, Ali A; Grundler, Florian M W; Siddique, Shahid

    2018-03-24

    Plant-parasitic cyst nematodes are obligate sedentary parasites that infect the roots of a broad range of host plants. Cyst nematodes are sexually dimorphic, but differentiation into male or female is strongly influenced by interactions with the host environment. Female populations typically predominate under favorable conditions, whereas male populations predominate under adverse conditions. Here, we performed a genome-wide association study (GWAS) in an Arabidopsis diversity panel to identify host loci underlying variation in susceptibility to cyst nematode infection. Three different susceptibility parameters were examined, with the aim of providing insights into the infection process, the number of females and males present in the infected plant, and the female-to-male sex ratio. GWAS results suggested that variation in sex ratio is associated with a novel quantitative trait locus allele on chromosome 4. Subsequent candidate genes and functional analyses revealed that a senescence-associated transcription factor, AtS40-3, and PPR may act in combination to influence nematode sex ratio. A detailed molecular characterization revealed that variation in nematode sex ratio was due to the disturbed common promoter of AtS40-3 and PPR genes. Additionally, single nucleotide polymorphisms in the coding sequence of AtS40-3 might contribute to the natural variation in nematode sex ratio.

  6. The diverse nematicidal properties and biocontrol efficacy of Bacillus thuringiensis Cry6A against the root-knot nematode Meloidogyne hapla.

    Science.gov (United States)

    Yu, Ziquan; Xiong, Jing; Zhou, Qiaoni; Luo, Haiyan; Hu, Shengbiao; Xia, Liqiu; Sun, Ming; Li, Lin; Yu, Ziniu

    2015-02-01

    Cry6A toxin from Bacillus thuringiensis is a representative nematicidal crystal protein with a variety of nematicidal properties to free-living nematode Caenorhabditis elegans. Cry6A shares very low homology and different structure with Cry5B, another representative nematicidal crystal protein, and probably acts in a distinct pathway. All these strongly indicate that Cry6A toxin is likely a potent candidate for nematicide. The present study dealt with global investigation to determine the detrimental impacts of Cry6Aa2 toxin on Meloidogyne hapla, a root-knot nematode, and evaluated its biocontrol efficacy in pot experiment. Obtained results indicated that Cry6Aa2 toxin exhibits obvious toxicity to second-stage juvenile of M. hapla, and significantly inhibits egg hatch, motility, and penetration to host plant. Pot experiment suggested that soil drenching with spore-crystal mixture of Cry6Aa2 can clearly lighten the disease of root-knot nematode, including reduction of galling index and egg masses on host plant root, decreasing final population of nematode in soil. Moreover, application of Cry6Aa2 can obviously promote plant growth. These results demonstrated that Cry6Aa2 toxin is a promising nematicidal agent, and possesses great potential in plant-parasitic nematode management and construction of transgenic crop with constant resistance to nematode. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Nematode cholinergic pharmacology

    International Nuclear Information System (INIS)

    Segerberg, M.A.

    1989-01-01

    Nematode acetylcholine (ACh) receptors were characterized using both biochemical and electrophysiological techniques, including: (1) receptor binding studies in crude homogenates of the free-living nematode Caenorhabditis elegans and the parasitic nematode Ascaris lumbricoides with the high-affinity probe [ 3 H]N-methylscopolamine ([ 3 H]NMS) which binds to muscarinic receptors in many vertebrate and invertebrate tissues (2) measurement of depolarization and contraction induced by a variety of cholinergic agents, including N-methylscopolamine (NMS), in an innervated dorsal muscle strip preparation of Ascaris; (3) examination of the antagonistic actions of d-tubocurarine (dTC) and NMS at dorsal neuromuscular junction; (4) measurement of input resistance changes in Ascaris commissural motorneurons induced by ACh, dTC, NMS, pilocarpine and other cholinergic drugs

  8. Alternative splicing: a novel mechanism of regulation identified in the chorismate mutase gene of the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Lu, Shun-Wen; Tian, Duanhua; Borchardt-Wier, Harmony B; Wang, Xiaohong

    2008-11-01

    Chorismate mutase (CM) secreted from the stylet of plant-parasitic nematodes plays an important role in plant parasitism. We isolated and characterized a new nematode CM gene (Gr-cm-1) from the potato cyst nematode, Globodera rostochiensis. The Gr-cm-1 gene was found to exist in the nematode genome as a single-copy gene that has two different alleles, Gr-cm-1A and Gr-cm-1B, both of which could give rise to two different mRNA transcripts of Gr-cm-1 and Gr-cm-1-IRII. In situ mRNA hybridization showed that the Gr-cm-1 gene was exclusively expressed within the subventral oesophageal gland cells of the nematode. Gr-cm-1 was demonstrated to encode a functional CM (GR-CM-1) potentially having a dimeric structure as the secreted bacterial *AroQ CMs. Gr-cm-1-IRII, generated by retention of intron 2 of the Gr-cm-1 pre-mRNA through alternative splicing (AS), would encode a truncated protein (GR-CM-1t) lacking the CM domain with no CM activity. The quantitative real-time reverse transcription-PCR assay revealed that splicing of the Gr-cm-1 gene was developmentally regulated; Gr-cm-1 was up-regulated whereas Gr-cm-1-IRII was down-regulated in early nematode parasitic stages compared to the preparasitic juvenile stage. Low-temperature SDS-PAGE analysis revealed that GR-CM-1 could form homodimers when expressed in Escherichia coli and the dimerization domain was retained in the truncated GR-CM-1t protein. The specific interaction between the two proteins was demonstrated in yeast. Our data suggested that the novel splice variant might function as a dominant negative isoform through heterodimerization with the full-length GR-CM-1 protein and that AS may represent an important mechanism for regulating CM activity during nematode parasitism.

  9. Detection and characterization of Pasteuria 16S rRNA gene sequences from nematodes and soils.

    Science.gov (United States)

    Duan, Y P; Castro, H F; Hewlett, T E; White, J H; Ogram, A V

    2003-01-01

    Various bacterial species in the genus Pasteuria have great potential as biocontrol agents against plant-parasitic nematodes, although study of this important genus is hampered by the current inability to cultivate Pasteuria species outside their host. To aid in the study of this genus, an extensive 16S rRNA gene sequence phylogeny was constructed and this information was used to develop cultivation-independent methods for detection of Pasteuria in soils and nematodes. Thirty new clones of Pasteuria 16S rRNA genes were obtained directly from nematodes and soil samples. These were sequenced and used to construct an extensive phylogeny of this genus. These sequences were divided into two deeply branching clades within the low-G + C, Gram-positive division; some sequences appear to represent novel species within the genus Pasteuria. In addition, a surprising degree of 16S rRNA gene sequence diversity was observed within what had previously been designated a single strain of Pasteuria penetrans (P-20). PCR primers specific to Pasteuria 16S rRNA for detection of Pasteuria in soils were also designed and evaluated. Detection limits for soil DNA were 100-10,000 Pasteuria endospores (g soil)(-1).

  10. The novel nematicide wact-86 interacts with aldicarb to kill nematodes.

    Directory of Open Access Journals (Sweden)

    Andrew R Burns

    2017-04-01

    Full Text Available Parasitic nematodes negatively impact human and animal health worldwide. The market withdrawal of nematicidal agents due to unfavourable toxicities has limited the available treatment options. In principle, co-administering nematicides at lower doses along with molecules that potentiate their activity could mitigate adverse toxicities without compromising efficacy. Here, we screened for new small molecules that interact with aldicarb, which is a highly effective treatment for plant-parasitic nematodes whose toxicity hampers its utility. From our collection of 638 worm-bioactive compounds, we identified 20 molecules that interact positively with aldicarb to either kill or arrest the growth of the model nematode Caenorhabditis elegans. We investigated the mechanism of interaction between aldicarb and one of these novel nematicides called wact-86. We found that the carboxylesterase enzyme GES-1 hydrolyzes wact-86, and that the interaction is manifested by aldicarb's inhibition of wact-86's metabolism by GES-1. This work demonstrates the utility of C. elegans as a platform to search for new molecules that can positively interact with industrial nematicides, and provides proof-of-concept for prospective discovery efforts.

  11. Optimizing the efficacy of Paecilomyces lilacinus (strain 251) for the control of root-knot nematodes.

    Science.gov (United States)

    Kiewnick, S; Sikora, R A

    2004-01-01

    The egg pathogenic fungus Paecilomyces lilacinus (strain 251) is a biocontrol fungus with a potential range of activity to control the worldwide most important plant parasitic nematodes. This biological nematicide may be an useful tool in an integrated approach to control mainly sedentary nematodes. Greenhouse experiments were conducted with the root-knot nematodes Meloidogyne incognita and M. hapla on tomato. P. lilacinus, formulated as WG (BIOACT WG), was incorporated into soil inoculated with root-knot nematode eggs prior to transplanting the susceptible tomato cultivar "Hellfrucht". Furthermore, soil treatments were combined with seedling treatments 24 hours before transplanting and a soil drench 2 weeks after planting, respectively. Seedling and post planting treatment was also combined with a soil treatment at planting. All single or combination treatments tested decreased the gall index and the number of egg masses compared to the untreated control 12 weeks after planting. However, the combination of the seedling treatment with a pre- or at-planting application of P. lilacinus was necessary to achieve higher levels of control. Additional post plant drenching resulted in only a slight increase In efficacy. To the feasibility of this modified application system for the control of root-knot nematodes, a yield experiment was conducted with M. hapla and the susceptible cultivar "Gnom F1 Hybrid". It could be demonstrated that the above mentioned combination of pre-planting application plus the seedling and one post plant drench gave the best control and resulted in a significant fruit yield increase in concurrence with a decrease in number of galls per root.

  12. Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism[C][W][OA

    Science.gov (United States)

    Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M.; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

    2012-01-01

    Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA–mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection. PMID:22822208

  13. Progressive metabolic impairment underlies the novel nematicidal action of fluensulfone on the potato cyst nematode Globodera pallida.

    Science.gov (United States)

    Kearn, James; Lilley, Catherine; Urwin, Peter; O'Connor, Vincent; Holden-Dye, Lindy

    2017-10-01

    Fluensulfone is a new nematicide with an excellent profile of selective toxicity against plant parasitic nematodes. Here, its effects on the physiology and biochemistry of the potato cyst nematode Globodera pallida have been investigated and comparisons made with its effect on the life-span of the free-living nematode Caenorhabditis elegans to provide insight into its mode of action and its selective toxicity. Fluensulfone exerts acute effects (≤1h; ≥100μM) on stylet thrusting and motility of hatched second stage G. pallida juveniles (J2s). Chronic exposure to lower concentrations of fluensulfone (≥3days; ≤30μM), reveals a slowly developing metabolic insult in which G. pallida J2s sequentially exhibit a reduction in motility, loss of a metabolic marker for cell viability, high lipid content and tissue degeneration prior to death. These effects are absent in adults and dauers of the model genetic nematode Caenorhabditis elegans. The nematicidal action of fluensulfone follows a time-course which progresses from an early impact on motility through to an accumulating metabolic impairment, an inability to access lipid stores and death. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Long-term in vitro system for maintenance and amplification of root-knot nematodes in Cucumis sativus roots

    Directory of Open Access Journals (Sweden)

    Fernando E. eDíaz-Manzano

    2016-02-01

    Full Text Available Root-knot nematodes (RKN are polyphagous plant-parasitic roundworms that produce large crop losses, representing a relevant agricultural pest worldwide. After infection, they induce swollen root structures called galls containing giant cells (GCs indispensable for nematode development. Among efficient control methods are biotechnology-based strategies that require a deep knowledge of underlying molecular processes during the plant-nematode interaction. Methods of achieving this knowledge include the application of molecular biology techniques such as transcriptomics (massive sequencing or microarray hybridization, proteomics or metabolomics. These require aseptic experimental conditions, as undetected contamination with other microorganisms could compromise the interpretation of the results. Herein, we present a simple, efficient and long-term method for nematode amplification on cucumber roots grown in vitro. Amplification of juveniles (J2 from the starting inoculum is around 40-fold. The method was validated for three Meloidogyne species (M. javanica, M. incognita and M. arenaria, producing viable and robust freshly hatched J2s. These can be used for further in vitro infection of different plant species such as Arabidopsis, tobacco and tomato, as well as enough J2s to maintain the population. The method allowed maintenance of around 90 Meloidogyne spp. generations (one every two months from a single initial female over 15 years.

  15. The Role of Programmed Cell Death Regulator LSD1 in Nematode-Induced Syncytium Formation

    Science.gov (United States)

    Matuszkiewicz, Mateusz; Sobczak, Miroslaw; Cabrera, Javier; Escobar, Carolina; Karpiński, Stanislaw; Filipecki, Marcin

    2018-01-01

    Cyst-forming plant-parasitic nematodes are common pests of many crops. They inject secretions into host cells to induce the developmental and metabolic reprogramming that leads to the formation of a syncytium, which is the sole food source for growing nematodes. As in other host-parasite models, avirulence leads to rapid and local programmed cell death (PCD) known as the hypersensitive response (HR), whereas in the case of virulence, PCD is still observed but is limited to only some cells. Several regulators of PCD were analyzed to understand the role of PCD in compatible plant–nematode interactions. Thus, Arabidopsis plants carrying recessive mutations in LESION SIMULATING DISEASE1 (LSD1) family genes were subjected to nematode infection assays with juveniles of Heterodera schachtii. LSD1 is a negative and conditional regulator of PCD, and fewer and smaller syncytia were induced in the roots of lsd1 mutants than in wild-type Col-0 plants. Mutation in LSD ONE LIKE2 (LOL2) revealed a pattern of susceptibility to H. schachtii antagonistic to lsd1. Syncytia induced on lsd1 roots compared to Col0 showed significantly retarded growth, modified cell wall structure, increased vesiculation, and some myelin-like bodies present at 7 and 12 days post-infection. To place these data in a wider context, RNA-sequencing analysis of infected and uninfected roots was conducted. During nematode infection, the number of transcripts with changed expression in lsd1 was approximately three times smaller than in wild-type plants (1440 vs. 4206 differentially expressed genes, respectively). LSD1-dependent PCD in roots is thus a highly regulated process in compatible plant–nematode interactions. Two genes identified in this analysis, coding for AUTOPHAGY-RELATED PROTEIN 8F and 8H were down-regulated in syncytia in the presence of LSD1 and showed an increased susceptibility to nematode infection contrasting with lsd1 phenotype. Our data indicate that molecular regulators belonging to the

  16. The Role of Programmed Cell Death Regulator LSD1 in Nematode-Induced Syncytium Formation

    Directory of Open Access Journals (Sweden)

    Mateusz Matuszkiewicz

    2018-03-01

    Full Text Available Cyst-forming plant-parasitic nematodes are common pests of many crops. They inject secretions into host cells to induce the developmental and metabolic reprogramming that leads to the formation of a syncytium, which is the sole food source for growing nematodes. As in other host-parasite models, avirulence leads to rapid and local programmed cell death (PCD known as the hypersensitive response (HR, whereas in the case of virulence, PCD is still observed but is limited to only some cells. Several regulators of PCD were analyzed to understand the role of PCD in compatible plant–nematode interactions. Thus, Arabidopsis plants carrying recessive mutations in LESION SIMULATING DISEASE1 (LSD1 family genes were subjected to nematode infection assays with juveniles of Heterodera schachtii. LSD1 is a negative and conditional regulator of PCD, and fewer and smaller syncytia were induced in the roots of lsd1 mutants than in wild-type Col-0 plants. Mutation in LSD ONE LIKE2 (LOL2 revealed a pattern of susceptibility to H. schachtii antagonistic to lsd1. Syncytia induced on lsd1 roots compared to Col0 showed significantly retarded growth, modified cell wall structure, increased vesiculation, and some myelin-like bodies present at 7 and 12 days post-infection. To place these data in a wider context, RNA-sequencing analysis of infected and uninfected roots was conducted. During nematode infection, the number of transcripts with changed expression in lsd1 was approximately three times smaller than in wild-type plants (1440 vs. 4206 differentially expressed genes, respectively. LSD1-dependent PCD in roots is thus a highly regulated process in compatible plant–nematode interactions. Two genes identified in this analysis, coding for AUTOPHAGY-RELATED PROTEIN 8F and 8H were down-regulated in syncytia in the presence of LSD1 and showed an increased susceptibility to nematode infection contrasting with lsd1 phenotype. Our data indicate that molecular regulators

  17. FMRFamide-related peptides in potato cyst nematodes.

    Science.gov (United States)

    Kimber, M J; Fleming, C C; Bjourson, A J; Halton, D W; Maule, A G

    2001-09-03

    This study presents data demonstrating the presence of FMRFamide-related peptides (FaRPs) in potato cyst nematodes (PCN). Five transcripts of FaRP encoding genes, designated gpflp-1 to gpflp-5, were characterised using RACE. In terms of ORFs, gpflp-1 was 444 base pairs (bp) long and coded for four copies of the FaRP, PF3 (KSAYMRFamide) whilst gpflp-2 was 309 bp long and encoded one copy of the peptide, KNKFEFIRFamide. gpflp-3 (420 bp) Encoded two copies of KHEYLRFamide (AF2) and the genes gpflp-4 and gpflp-5 encoded a total of 11 FaRPs, most of which are novel to PCN. FMRFamide-related peptide (FaRP)-like immunoreactivity was observed in both PCN species, Globodera pallida and Globodera rostochiensis, using an antiserum raised against the invertebrate peptide, FMRFamide. Immunopositive neurones were found throughout the central nervous system in the ventral and dorsal nerve cords and the circumpharyngeal and perianal nerve rings. Reactive neurones were also present peripherally, innervating the highly muscular pharynx with a nerve net and ring-like structures. Positive immunostaining was also observed in neurones running toward the stylet protractor muscles and/or the anterior sensory apparatus. This study implicates a role for FaRPs in feeding, host penetration and sensory function of PCN. This is the first study to characterise FaRP encoding genes from a plant-parasitic nematode using a targeted PCR based RACE approach and further underlines the importance and diversity of this neuropeptide group in the phylum Nematoda.

  18. Towards multi-level biomonitoring of nematodes to assess risk of nitrogen and phosphorus pollution in Jinchuan Wetland of Northeast China.

    Science.gov (United States)

    Wang, Yunbiao; Qiao, Jie; He, Chunguang; Wang, Zhongqiang; Luo, Wenbo; Sheng, Lianxi

    2015-12-01

    Cultivation for agricultural production often poses threats to nearby wetlands ecosystems in fertile landscapes. In this study, nematode ecological indexes were assessed through the main soil properties of the wetlands, farmlands, and edges of wetlands and farmlands in Jinchuan Wetland by the random sampling. Behavior and reproduction in Caenorhabditis elegans (C. elegans) exposed to the sampled waters were also examined. Stress proteins Hsp70 and Hsp90 were measured both in the living field samples of C. elegans and the lab-tested C. elegans. Our results suggested that disturbance to wetland ecosystems by nitrogen and phosphorus reduced nematode richness and proportions of bacterivore nematodes. Bacterivore nematode diversity and plant-parasitic ecological index were proven to be sensitive indicators of the ecological health of wetlands. Nematode Hsp70 were useful biosensors to monitor and assess the levels of nitrogen and phosphorus pollutions in wetlands. Furthermore, multi-level soil faunal assessments by canonical correspondence analysis showed that Jinchuan Wetland is threatened with non-point source pollution from nearby farmlands.

  19. Impact of No-till Cover Cropping of Italian Ryegrass on Above and Below Ground Faunal Communities Inhabiting a Soybean Field with Emphasis on Soybean Cyst Nematodes.

    Science.gov (United States)

    Hooks, Cerruti R R; Wang, Koon-Hui; Meyer, Susan L F; Lekveishvili, Mariam; Hinds, Jermaine; Zobel, Emily; Rosario-Lebron, Armando; Lee-Bullock, Mason

    2011-09-01

    Two field trials were conducted between 2008 and 2010 in Maryland to evaluate the ability of an Italian ryegrass (IR) (Lolium multiflorum) cover crop to reduce populations of plant-parasitic nematodes while enhancing beneficial nematodes, soil mites and arthropods in the foliage of a no-till soybean (Glycine max) planting. Preplant treatments were: 1) previous year soybean stubble (SBS); and 2) herbicide-killed IR cover crop + previous year soybean stubble (referred to as IR). Heterodera glycines population densities were very low and no significant difference in population densities of H. glycines or Pratylenchus spp. were observed between IR and SBS. Planting of IR increased abundance of bacterivorous nematodes in 2009. A reverse trend was observed in 2010 where SBS had higher abundance of bacterivorous nematodes and nematode richness at the end of the cover cropping period. Italian ryegrass also did not affect insect pests on soybean foliage. However, greater populations of spiders were found on soybean foliage in IR treatments during both field trials. Potential causes of these findings are discussed.

  20. A novel serine protease, Sep1, from Bacillus firmus DS-1 has nematicidal activity and degrades multiple intestinal-associated nematode proteins.

    Science.gov (United States)

    Geng, Ce; Nie, Xiangtao; Tang, Zhichao; Zhang, Yuyang; Lin, Jian; Sun, Ming; Peng, Donghai

    2016-04-27

    Plant-parasitic nematodes (PPNs) cause serious harm to agricultural production. Bacillus firmus shows excellent control of PPNs and has been produced as a commercial nematicide. However, its nematicidal factors and mechanisms are still unknown. In this study, we showed that B. firmus strain DS-1 has high toxicity against Meloidogyne incognita and soybean cyst nematode. We sequenced the whole genome of DS-1 and identified multiple potential virulence factors. We then focused on a peptidase S8 superfamily protein called Sep1 and demonstrated that it had toxicity against the nematodes Caenorhabditis elegans and M. incognita. The Sep1 protein exhibited serine protease activity and degraded the intestinal tissues of nematodes. Thus, the Sep1 protease of B. firmus is a novel biocontrol factor with activity against a root-knot nematode. We then used C. elegans as a model to elucidate the nematicidal mechanism of Sep1, and the results showed that Sep1 could degrade multiple intestinal and cuticle-associated proteins and destroyed host physical barriers. The knowledge gained in our study will lead to a better understanding of the mechanisms of B. firmus against PPNs and will aid in the development of novel bio-agents with increased efficacy for controlling PPNs.

  1. The evolutionary position of nematodes

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    Gojobori Takashi

    2002-04-01

    Full Text Available Abstract Background The complete genomes of three animals have been sequenced by global research efforts: a nematode worm (Caenorhabditis elegans, an insect (Drosophila melanogaster, and a vertebrate (Homo sapiens. Remarkably, their relationships have yet to be clarified. The confusion concerns the enigmatic position of nematodes. Traditionally, nematodes have occupied a basal position, in part because they lack a true body cavity. However, the leading hypothesis now joins nematodes with arthropods in a molting clade, Ecdysozoa, based on data from several genes. Results We tested the Ecdysozoa hypothesis with analyses of more than 100 nuclear protein alignments, under conditions that would expose biases, and found that it was not supported. Instead, we found significant support for the traditional hypothesis, Coelomata. Our result is robust to different rates of sequence change among genes and lineages, different numbers of taxa, and different species of nematodes. Conclusion We conclude that insects (arthropods are genetically and evolutionarily closer to humans than to nematode worms.

  2. Molecular and Morphological Characterization and Biological Control Capabilities of a Pasteuria ssp. Parasitizing Rotylenchulus reniformis, the Reniform Nematode.

    Science.gov (United States)

    Schmidt, Liesbeth M; Hewlett, Thomas E; Green, April; Simmons, Lee J; Kelley, Karen; Doroh, Mark; Stetina, Salliana R

    2010-09-01

    Rotylenchulus reniformis is one of 10 described species of reniform nematodes and is considered the most economically significant pest within the genus, parasitizing a variety of important agricultural crops. Rotylenchulus reniformis collected from cotton fields in the Southeastern US were observed to have the nematode parasitic bacterium Pasteuria attached to their cuticles. Challenge with a Pasteuria-specific monoclonal antibody in live immuno-fluorescent assay (IFA) confirmed the discovery of Pasteuria infecting R. reniformis. Scanning and transmission electron microscopy were employed to observe endospore ultrastructure and sporogenesis within the host. Pasteuria were observed to infect and complete their life-cycle in juvenile, male and female R. reniformis. Molecular analysis using Pasteuria species-specific and degenerate primers for 16s rRNA and spoII, and subsequent phylogenetic assessment, placed the Pasteuria associated with R. reniformis in a distinct clade within established assemblages for the Pasteuria infecting phytopathogenic nematodes. A global phylogenetic assessment of Pasteuria 16s rDNA using the Neighbor-Joining method resulted in a clear branch with 100% boot-strap support that effectively partitioned the Pasteuria infecting phytopathogenic nematodes from the Pasteuria associated with bacterivorous nematodes. Phylogenetic analysis of the R. reniformis Pasteuria and Pasteuria spp. parasitizing a number of economically important plant parasitic nematodes revealed that Pasteuria with different host specificities are closely related and likely constitute biotypes of the same species. This suggests host preference, and thus effective differentiation and classification are most likely predicated by an influential virulence determinant(s) that has yet to be elucidated. Pasteuria Pr3 endospores produced by in vitro fermentation demonstrated efficacy as a commercial bionematicide to control R. reniformis on cotton in pot tests, when applied as a seed

  3. A northward colonisation of the Andes by the potato cyst nematode during geological times suggests multiple host-shifts from wild to cultivated potatoes.

    Science.gov (United States)

    Picard, Damien; Sempere, Thierry; Plantard, Olivier

    2007-02-01

    The cyst nematode Globodera pallida is a major pest of potato in South America where this specialist parasite is native. To investigate its phylogeography, we have genotyped individuals from 42 Peruvian populations using mitochondrial and nuclear molecular markers. A clear south-to-north phylogeographical pattern was revealed with five well-supported clades. The clade containing the southern populations is genetically more diverse and forms the most basal branch. The large divergence among cytochrome b haplotypes suggests that they diverged before human domestication of potato. As the nematodes studied have been sampled on cultivated potato, multiple host-shifts from wild to cultivated potatoes must have occurred independently in each clade. We hypothesise that this south-to-north pattern took place during the uplift of the Andes beginning 20 My ago and following the same direction. To our knowledge, this is the first study of a plant parasite sampled on cultivated plants revealing an ancient phylogeographical pattern.

  4. Identification of Nematode Fauna in Vineyards of South of Western Azerbaijan and Determination of the Dominant Parasitic Species

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    E. Mohajeri

    2017-12-01

    Full Text Available Introduction: Grapevine belongs to the Vitaceae family that consists of 14 genera and about 700 species. Only in the genus Vitis fruits are edible. Italy is the largest producer of grapes and Iran has the seventh position in the world from this point of view. Western Azarbaijan province comprises a high diversity of crops including wild grapes. Although, some nematodes are free living and antagonists of another soil microfauna, the other are plant parasitic agents. Most of which live in the agricultural soils where they are widely dispersed. Effectiveness of the disease management strategies are affected by the accurate identification of the plant disease causal agents and the nematodal diseases are not the exception from this rule. Therefore, for control of the diseases caused by the nematodes, it is necessary to separate the parasitic nematodes from the suspected contaminated soils and identify them. Although separation and identification of the nematodes are partly time-consuming, it is not very complicated. Some nematodes likeXiphinema, Longidorus and Ditylenchus are cosmopolitan and catastrophic nematodes in vineyards worldwide. So far no study has been performed regarding the plant parasitic nematode in vineyards of the south of Western Azerbaijan. Therefore, in this study as an introduction to the management ofthe vineyard parasitic nematodes, the dominant nematodes of the plant were identified. In the next step, investigation of nematodes bioecology, the interaction of nematodes with the other plant pathogens, their host range and their damages to the host plants would be studied. Materials and Methods: In order to identify the fauna of plant parasitic nematodes in vineyards of the south of Western Azarbaijan, during 2013-2014, 50 soil samples were collected from the rhizosphere of grapevine. The sampling was carried out from the vineyards of five grapevine growing cities including Mahabad, Bookan, Sardasht, Piranshahr and Miyandoab. The

  5. Variation in the susceptibility of Drosophila to different entomopathogenic nematodes.

    Science.gov (United States)

    Peña, Jennifer M; Carrillo, Mayra A; Hallem, Elissa A

    2015-03-01

    Entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema are lethal parasites of insects that are of interest as models for understanding parasite-host interactions and as biocontrol agents for insect pests. EPNs harbor a bacterial endosymbiont in their gut that assists in insect killing. EPNs are capable of infecting and killing a wide range of insects, yet how the nematodes and their bacterial endosymbionts interact with the insect immune system is poorly understood. Here, we develop a versatile model system for understanding the insect immune response to parasitic nematode infection that consists of seven species of EPNs as model parasites and five species of Drosophila fruit flies as model hosts. We show that the EPN Steinernema carpocapsae, which is widely used for insect control, is capable of infecting and killing D. melanogaster larvae. S. carpocapsae is associated with the bacterium Xenorhabdus nematophila, and we show that X. nematophila induces expression of a subset of antimicrobial peptide genes and suppresses the melanization response to the nematode. We further show that EPNs vary in their virulence toward D. melanogaster and that Drosophila species vary in their susceptibilities to EPN infection. Differences in virulence among different EPN-host combinations result from differences in both rates of infection and rates of postinfection survival. Our results establish a powerful model system for understanding mechanisms of host-parasite interactions and the insect immune response to parasitic nematode infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Investigation on the infection mechanism of the fungus Clonostachys rosea against nematodes using the green fluorescent protein.

    Science.gov (United States)

    Zhang, Lin; Yang, Jinkui; Niu, Qiuhong; Zhao, Xuna; Ye, Fengping; Liang, Lianming; Zhang, Ke-Qin

    2008-04-01

    The fungus Clonostachys rosea (syn. Gliocladium roseum) is a potential biocontrol agent. It can suppress the sporulation of the plant pathogenic fungus Botrytis cinerea and kill pathogenic nematodes, but the process of nematode pathogenesis is poorly understood. To help understand the underlying mechanism, we constructed recombinant strains containing a plasmid with both the enhanced green fluorescent protein gene egfp and the hygromycin resistance gene hph. Expression of the green fluorescent protein (GFP) was monitored using fluorescence microscopy. Our observations reveal that the pathogenesis started from the adherence of conidia to nematode cuticle for germination, followed by the penetration of germ tubes into the nematode body and subsequent death and degradation of the nematodes. These are the first findings on the infection process of the fungal pathogen marked with GFP, and the developed method can become an important tool for studying the molecular mechanisms of nematode infection by C. rosea.

  7. Characterization of Three Novel Fatty Acid- and Retinoid-Binding Protein Genes (Ha-far-1, Ha-far-2 and Hf-far-1 from the Cereal Cyst Nematodes Heterodera avenae and H. filipjevi.

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    Fen Qiao

    Full Text Available Heterodera avenae and H. filipjevi are major parasites of wheat, reducing production worldwide. Both are sedentary endoparasitic nematodes, and their development and parasitism depend strongly on nutrients obtained from hosts. Secreted fatty acid- and retinol-binding (FAR proteins are nematode-specific lipid carrier proteins used for nutrient acquisition as well as suppression of plant defenses. In this study, we obtained three novel FAR genes Ha-far-1 (KU877266, Ha-far-2 (KU877267, Hf-far-1 (KU877268. Ha-far-1 and Ha-far-2 were cloned from H. avenae, encoding proteins of 191 and 280 amino acids with molecular masses about 17 and 30 kDa, respectively and sequence identity of 28%. Protein Blast in NCBI revealed that Ha-FAR-1 sequence is 78% similar to the Gp-FAR-1 protein from Globodera pallida, while Ha-FAR-2 is 30% similar to Rs-FAR-1 from Radopholus similis. Only one FAR protein Hf-FAR-1was identified in H. filipjevi; it had 96% sequence identity to Ha-FAR-1. The three proteins are alpha-helix-rich and contain the conserved domain of Gp-FAR-1, but Ha-FAR-2 had a remarkable peptide at the C-terminus which was random-coil-rich. Both Ha-FAR-1 and Hf-FAR-1 had casein kinase II phosphorylation sites, while Ha-FAR-2 had predicted N-glycosylation sites. Phylogenetic analysis showed that the three proteins clustered together, though Ha-FAR-1 and Hf-FAR-1 adjoined each other in a plant-parasitic nematode branch, but Ha-FAR-2 was distinct from the other proteins in the group. Fluorescence-based ligand binding analysis showed the three FAR proteins bound to a fluorescent fatty acid derivative and retinol and with dissociation constants similar to FARs from other species, though Ha-FAR-2 binding ability was weaker than that of the two others. In situ hybridization detected mRNAs of Ha-far-1 and Ha-far-2 in the hypodermis. The qRT-PCR results showed that the Ha-far-1and Ha-far-2 were expressed in all developmental stages; Ha-far-1 expressed 70 times more

  8. Characterization of Three Novel Fatty Acid- and Retinoid-Binding Protein Genes (Ha-far-1, Ha-far-2 and Hf-far-1) from the Cereal Cyst Nematodes Heterodera avenae and H. filipjevi.

    Science.gov (United States)

    Qiao, Fen; Luo, Lilian; Peng, Huan; Luo, Shujie; Huang, Wenkun; Cui, Jiangkuan; Li, Xin; Kong, Lingan; Jiang, Daohong; Chitwood, David J; Peng, Deliang

    2016-01-01

    Heterodera avenae and H. filipjevi are major parasites of wheat, reducing production worldwide. Both are sedentary endoparasitic nematodes, and their development and parasitism depend strongly on nutrients obtained from hosts. Secreted fatty acid- and retinol-binding (FAR) proteins are nematode-specific lipid carrier proteins used for nutrient acquisition as well as suppression of plant defenses. In this study, we obtained three novel FAR genes Ha-far-1 (KU877266), Ha-far-2 (KU877267), Hf-far-1 (KU877268). Ha-far-1 and Ha-far-2 were cloned from H. avenae, encoding proteins of 191 and 280 amino acids with molecular masses about 17 and 30 kDa, respectively and sequence identity of 28%. Protein Blast in NCBI revealed that Ha-FAR-1 sequence is 78% similar to the Gp-FAR-1 protein from Globodera pallida, while Ha-FAR-2 is 30% similar to Rs-FAR-1 from Radopholus similis. Only one FAR protein Hf-FAR-1was identified in H. filipjevi; it had 96% sequence identity to Ha-FAR-1. The three proteins are alpha-helix-rich and contain the conserved domain of Gp-FAR-1, but Ha-FAR-2 had a remarkable peptide at the C-terminus which was random-coil-rich. Both Ha-FAR-1 and Hf-FAR-1 had casein kinase II phosphorylation sites, while Ha-FAR-2 had predicted N-glycosylation sites. Phylogenetic analysis showed that the three proteins clustered together, though Ha-FAR-1 and Hf-FAR-1 adjoined each other in a plant-parasitic nematode branch, but Ha-FAR-2 was distinct from the other proteins in the group. Fluorescence-based ligand binding analysis showed the three FAR proteins bound to a fluorescent fatty acid derivative and retinol and with dissociation constants similar to FARs from other species, though Ha-FAR-2 binding ability was weaker than that of the two others. In situ hybridization detected mRNAs of Ha-far-1 and Ha-far-2 in the hypodermis. The qRT-PCR results showed that the Ha-far-1and Ha-far-2 were expressed in all developmental stages; Ha-far-1 expressed 70 times more than Ha-far-2 in

  9. Structural and functional diversity of CLAVATA3/ESR (CLE)-like genes from the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Lu, Shun-Wen; Chen, Shiyan; Wang, Jianying; Yu, Hang; Chronis, Demosthenis; Mitchum, Melissa G; Wang, Xiaohong

    2009-09-01

    Plant CLAVATA3/ESR-related (CLE) peptides have diverse roles in plant growth and development. Here, we report the isolation and functional characterization of five new CLE genes from the potato cyst nematode Globodera rostochiensis. Unlike typical plant CLE peptides that contain a single CLE motif, four of the five Gr-CLE genes encode CLE proteins with multiple CLE motifs. These Gr-CLE genes were found to be specifically expressed within the dorsal esophageal gland cell of nematode parasitic stages, suggesting a role for their encoded proteins in plant parasitism. Overexpression phenotypes of Gr-CLE genes in Arabidopsis mimicked those of plant CLE genes, and Gr-CLE proteins could rescue the Arabidopsis clv3-2 mutant phenotype when expressed within meristems. A short root phenotype was observed when synthetic GrCLE peptides were exogenously applied to roots of Arabidopsis or potato similar to the overexpression of Gr-CLE genes in Arabidopsis and potato hairy roots. These results reveal that G. rostochiensis CLE proteins with either single or multiple CLE motifs function similarly to plant CLE proteins and that CLE signaling components are conserved in both Arabidopsis and potato roots. Furthermore, our results provide evidence to suggest that the evolution of multiple CLE motifs may be an important mechanism for generating functional diversity in nematode CLE proteins to facilitate parasitism.

  10. Identification and characterization of parasitism genes from the pinewood nematode Bursaphelenchus xylophilus reveals a multilayered detoxification strategy.

    Science.gov (United States)

    Espada, Margarida; Silva, Ana Cláudia; Eves van den Akker, Sebastian; Cock, Peter J A; Mota, Manuel; Jones, John T

    2016-02-01

    The migratory endoparasitic nematode Bursaphelenchus xylophilus, which is the causal agent of pine wilt disease, has phytophagous and mycetophagous phases during its life cycle. This highly unusual feature distinguishes it from other plant-parasitic nematodes and requires profound changes in biology between modes. During the phytophagous stage, the nematode migrates within pine trees, feeding on the contents of parenchymal cells. Like other plant pathogens, B. xylophilus secretes effectors from pharyngeal gland cells into the host during infection. We provide the first description of changes in the morphology of these gland cells between juvenile and adult life stages. Using a comparative transcriptomics approach and an effector identification pipeline, we identify numerous novel parasitism genes which may be important for the mediation of interactions of B. xylophilus with its host. In-depth characterization of all parasitism genes using in situ hybridization reveals two major categories of detoxification proteins, those specifically expressed in either the pharyngeal gland cells or the digestive system. These data suggest that B. xylophilus incorporates effectors in a multilayer detoxification strategy in order to protect itself from host defence responses during phytophagy. © 2015 BSPP AND JOHN WILEY & SONS LTD.

  11. The plant cell wall in the feeding sites of cyst nematodes.

    Science.gov (United States)

    Bohlmann, Holger; Sobczak, Miroslaw

    2014-01-01

    Plant parasitic cyst nematodes (genera Heterodera and Globodera) are serious pests for many crops. They enter the host roots as migratory second stage juveniles (J2) and migrate intracellularly toward the vascular cylinder using their stylet and a set of cell wall degrading enzymes produced in the pharyngeal glands. They select an initial syncytial cell (ISC) within the vascular cylinder or inner cortex layers to induce the formation of a multicellular feeding site called a syncytium, which is the only source of nutrients for the parasite during its entire life. A syncytium can consist of more than hundred cells whose protoplasts are fused together through local cell wall dissolutions. While the nematode produces a cocktail of cell wall degrading and modifying enzymes during migration through the root, the cell wall degradations occurring during syncytium development are due to the plants own cell wall modifying and degrading proteins. The outer syncytial cell wall thickens to withstand the increasing osmotic pressure inside the syncytium. Furthermore, pronounced cell wall ingrowths can be formed on the outer syncytial wall at the interface with xylem vessels. They increase the surface of the symplast-apoplast interface, thus enhancing nutrient uptake into the syncytium. Processes of cell wall degradation, synthesis and modification in the syncytium are facilitated by a variety of plant proteins and enzymes including expansins, glucanases, pectate lyases and cellulose synthases, which are produced inside the syncytium or in cells surrounding the syncytium.

  12. Analysis of survival and hatching transcriptomes from potato cyst nematodes, Globodera rostochiensis and G. pallida.

    Science.gov (United States)

    Duceppe, Marc-Olivier; Lafond-Lapalme, Joël; Palomares-Rius, Juan Emilio; Sabeh, Michaël; Blok, Vivian; Moffett, Peter; Mimee, Benjamin

    2017-06-20

    Potato cyst nematodes (PCNs), Globodera rostochiensis and G. pallida, cause important economic losses. They are hard to manage because of their ability to remain dormant in soil for many years. Although general knowledge about these plant parasitic nematodes has considerably increased over the past decades, very little is known about molecular events involved in cyst dormancy and hatching, two key steps of their development. Here, we have studied the progression of PCN transcriptomes from dry cysts to hatched juveniles using RNA-Seq. We found that several cell detoxification-related genes were highly active in the dry cysts. Many genes linked to an increase of calcium and water uptake were up-regulated during transition from dormancy to hydration. Exposure of hydrated cysts to host plant root exudates resulted in different transcriptional response between species. After 48 h of exposure, G. pallida cysts showed no significant modulation of gene expression while G. rostochiensis had 278 differentially expressed genes. The first G. rostochiensis significantly up-regulated gene was observed after 8 h and was coding for a transmembrane metalloprotease. This enzyme is able to activate/inactivate peptide hormones and could be involved in a cascade of events leading to hatching. Several known effector genes were also up-regulated during hatching.

  13. Sampling Error in Relation to Cyst Nematode Population Density Estimation in Small Field Plots.

    Science.gov (United States)

    Župunski, Vesna; Jevtić, Radivoje; Jokić, Vesna Spasić; Župunski, Ljubica; Lalošević, Mirjana; Ćirić, Mihajlo; Ćurčić, Živko

    2017-06-01

    Cyst nematodes are serious plant-parasitic pests which could cause severe yield losses and extensive damage. Since there is still very little information about error of population density estimation in small field plots, this study contributes to the broad issue of population density assessment. It was shown that there was no significant difference between cyst counts of five or seven bulk samples taken per each 1-m 2 plot, if average cyst count per examined plot exceeds 75 cysts per 100 g of soil. Goodness of fit of data to probability distribution tested with χ 2 test confirmed a negative binomial distribution of cyst counts for 21 out of 23 plots. The recommended measure of sampling precision of 17% expressed through coefficient of variation ( cv ) was achieved if the plots of 1 m 2 contaminated with more than 90 cysts per 100 g of soil were sampled with 10-core bulk samples taken in five repetitions. If plots were contaminated with less than 75 cysts per 100 g of soil, 10-core bulk samples taken in seven repetitions gave cv higher than 23%. This study indicates that more attention should be paid on estimation of sampling error in experimental field plots to ensure more reliable estimation of population density of cyst nematodes.

  14. The plant cell wall in the feeding sites of cyst nematodes

    Directory of Open Access Journals (Sweden)

    Holger eBohlmann

    2014-03-01

    Full Text Available Plant parasitic cyst nematodes (genera Heterodera and Globodera are serious pests for many crops. They enter the host roots as migratory second stage juveniles (J2 and migrate intracellularly towards the vascular cylinder using their stylet and a set of cell wall degrading enzymes produced in the pharyngeal glands. They select an initial syncytial cell (ISC within the vascular cylinder or inner cortex layers to induce the formation of a multicellular feeding site called a syncytium, which is the only source of nutrients for the parasite during its entire life. A syncytium can consist of more than hundred cells whose protoplasts are fused together through local cell wall dissolutions. While the nematode produces a cocktail of cell wall degrading and modifying enzymes during migration through the root, the cell wall degradations occurring during syncytium development are due to the plants own cell wall modifying and degrading proteins. The outer syncytial cell wall thickens to withstand the increasing osmotic pressure inside the syncytium. Furthermore, pronounced cell wall ingrowths can be formed on the outer syncytial wall at the interface with xylem vessels. They increase the surface of the symplast-apoplast interface, thus enhancing nutrient uptake into the syncytium. Processes of cell wall degradation, synthesis and modification in the syncytium are facilitated by a variety of plant proteins and enzymes including expansins, glucanases, pectate lyases and cellulose synthases, which are produced inside the syncytium or in cells surrounding the syncytium.

  15. A realistic appraisal of methods to enhance desiccation tolerance of entomopathogenic nematodes.

    Science.gov (United States)

    Perry, Roland N; Ehlers, Ralf-Udo; Glazer, Itamar

    2012-06-01

    Understanding the desiccation survival attributes of infective juveniles of entomopathogenic nematodes (EPN) of the genera Steinernema and Heterorhabditis, is central to evaluating the reality of enhancing the shelf-life and field persistence of commercial formulations. Early work on the structural and physiological aspects of desiccation survival focused on the role of the molted cuticle in controlling the rate of water loss and the importance of energy reserves, particularly neutral lipids. The accumulation of trehalose was also found to enhance desiccation survival. Isolation of natural populations that can survive harsh environments, such as deserts, indicated that some populations have enhanced abilities to survive desiccation. However, survival abilities of EPN are limited compared with those of some species of plant-parasitic nematodes inhabiting aerial parts of plants. Research on EPN stress tolerance has expanded on two main lines: i) to select strains of species, currently in use commercially, which have increased tolerance to environmental extremes; and ii) to utilize molecular information, including expressed sequence tags and genome sequence data, to determine the underlying genetic factors that control longevity and stress tolerance of EPN. However, given the inherent limitations of EPN survival ability, it is likely that improved formulation will be the major factor to enhance EPN longevity and, perhaps, increase the range of applications.

  16. Molecular aspects of cyst nematodes.

    Science.gov (United States)

    Lilley, Catherine J; Atkinson, Howard J; Urwin, Peter E

    2005-11-01

    SUMMARY Taxonomy: Superkingdom Eukaryota; kingdom Metazoa; phylum Nematoda; class Chromadorea; order Tylenchida; suborder Tylenchina; superfamily Tylenchoidea; family Heteroderidae; subfamily Heteroderinae; main genera Heterodera and Globodera. Cyst nematodes comprise approximately 100 known species in six genera. They are pathogens of temperate, subtropical and tropical plant species and the host range of many species is narrow. The most economically important species are within the Globodera and Heterodera genera. Globodera pallida and G. rostochiensis are important pathogens of potato crops. There are many economic species in the Heterodera genus, including Heterodera glycines (soybean cyst nematode), H. avenae (cereal cyst nematode) and H. schachtii (sugar beet cyst nematode), the last of which attacks a range of Chenopodiaceae and Cruciferae, including Arabidopsis thaliana. Disease symptoms: Field symptoms of severe cyst nematode infection are often stunting, wilting and chlorosis, but considerable yield loss can occur without obvious symptoms. The only unique indicator of cyst nematode infection is the presence of adult female nematodes attached to host roots after several weeks of parasitism. Disease control: This is usually achieved by using integrated pest management involving cultural practices such as crop rotation, resistant cultivars if available and chemical control when economically justified.

  17. RNAi effector diversity in nematodes.

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    Johnathan J Dalzell

    2011-06-01

    Full Text Available While RNA interference (RNAi has been deployed to facilitate gene function studies in diverse helminths, parasitic nematodes appear variably susceptible. To test if this is due to inter-species differences in RNAi effector complements, we performed a primary sequence similarity survey for orthologs of 77 Caenorhabditis elegans RNAi pathway proteins in 13 nematode species for which genomic or transcriptomic datasets were available, with all outputs subjected to domain-structure verification. Our dataset spanned transcriptomes of Ancylostoma caninum and Oesophagostomum dentatum, and genomes of Trichinella spiralis, Ascaris suum, Brugia malayi, Haemonchus contortus, Meloidogyne hapla, Meloidogyne incognita and Pristionchus pacificus, as well as the Caenorhabditis species C. brenneri, C. briggsae, C. japonica and C. remanei, and revealed that: (i Most of the C. elegans proteins responsible for uptake and spread of exogenously applied double stranded (dsRNA are absent from parasitic species, including RNAi-competent plant-nematodes; (ii The Argonautes (AGOs responsible for gene expression regulation in C. elegans are broadly conserved, unlike those recruited during the induction of RNAi by exogenous dsRNA; (iii Secondary Argonautes (SAGOs are poorly conserved, and the nuclear AGO NRDE-3 was not identified in any parasite; (iv All five Caenorhabditis spp. possess an expanded RNAi effector repertoire relative to the parasitic nematodes, consistent with the propensity for gene loss in nematode parasites; (v In spite of the quantitative differences in RNAi effector complements across nematode species, all displayed qualitatively similar coverage of functional protein groups. In summary, we could not identify RNAi effector deficiencies that associate with reduced susceptibility in parasitic nematodes. Indeed, similarities in the RNAi effector complements of RNAi refractory and competent nematode parasites support the broad applicability of this research

  18. De Novo Assembly and Characterization of the Transcriptome of the Parasitic Weed Dodder Identifies Genes Associated with Plant Parasitism1[C][W][OPEN

    Science.gov (United States)

    Ranjan, Aashish; Ichihashi, Yasunori; Farhi, Moran; Zumstein, Kristina; Townsley, Brad; David-Schwartz, Rakefet; Sinha, Neelima R.

    2014-01-01

    Parasitic flowering plants are one of the most destructive agricultural pests and have major impact on crop yields throughout the world. Being dependent on finding a host plant for growth, parasitic plants penetrate their host using specialized organs called haustoria. Haustoria establish vascular connections with the host, which enable the parasite to steal nutrients and water. The underlying molecular and developmental basis of parasitism by plants is largely unknown. In order to investigate the process of parasitism, RNAs from different stages (i.e. seed, seedling, vegetative strand, prehaustoria, haustoria, and flower) were used to de novo assemble and annotate the transcriptome of the obligate plant stem parasite dodder (Cuscuta pentagona). The assembled transcriptome was used to dissect transcriptional dynamics during dodder development and parasitism and identified key gene categories involved in the process of plant parasitism. Host plant infection is accompanied by increased expression of parasite genes underlying transport and transporter categories, response to stress and stimuli, as well as genes encoding enzymes involved in cell wall modifications. By contrast, expression of photosynthetic genes is decreased in the dodder infective stages compared with normal stem. In addition, genes relating to biosynthesis, transport, and response of phytohormones, such as auxin, gibberellins, and strigolactone, were differentially expressed in the dodder infective stages compared with stems and seedlings. This analysis sheds light on the transcriptional changes that accompany plant parasitism and will aid in identifying potential gene targets for use in controlling the infestation of crops by parasitic weeds. PMID:24399359

  19. Apoplastic Venom Allergen-like Proteins of Cyst Nematodes Modulate the Activation of Basal Plant Innate Immunity by Cell Surface Receptors

    NARCIS (Netherlands)

    Lozano Torres, J.L.; Wilbers, R.H.P.; Warmerdam, S.; Finkers-Tomczak, A.M.; Diaz Granados Muñoz, A.; Schaik, van C.C.; Helder, J.; Bakker, J.; Goverse, A.; Schots, A.; Smant, G.

    2014-01-01

    Despite causing considerable damage to host tissue during the onset of parasitism, nematodes establish remarkably persistent infections in both animals and plants. It is thought that an elaborate repertoire of effector proteins in nematode secretions suppresses damage-triggered immune responses of

  20. Entomopathogenic nematodes in agricultural areas in Brazil.

    Science.gov (United States)

    de Brida, Andressa Lima; Rosa, Juliana Magrinelli Osório; Oliveira, Cláudio Marcelo Gonçalves de; Castro, Bárbara Monteiro de Castro E; Serrão, José Eduardo; Zanuncio, José Cola; Leite, Luis Garrigós; Wilcken, Silvia Renata Siciliano

    2017-04-06

    Entomopathogenic nematodes (EPNs) (Steinernematidae and Heterorhabditidae) can control pests due to the mutualistic association with bacteria that kill the host by septicemia and make the environment favorable for EPNs development and reproduction. The diversity of EPNs in Brazilian soils requires further study. The identification of EPNs, adapted to environmental and climatic conditions of cultivated areas is important for sustainable pest suppression in integrated management programs in agricultural areas of Brazil. The objective was to identify EPNs isolated from agricultural soils with annual, fruit and forest crops in Brazil. Soil samples were collected and stored in 250 ml glass vials. The nematodes were isolated from these samples with live bait traps ([Galleria mellonella L. (Lepidoptera: Pyralidae) larvae]. Infective juveniles were collected with White traps and identified by DNA barcoding procedures by sequencing the D2/D3 expansion of the 28S rDNA region by PCR. EPNs identified in agricultural areas in Brazil were Heterorhabditis amazonensis, Metarhabditis rainai, Oscheios tipulae and Steinernema rarum. These species should be considered pest biocontrol agents in Brazilian agricultural areas.

  1. The pinewood nematode, Bursaphelenchus xylophilus

    OpenAIRE

    Mota, Manuel; Vieira, Paulo

    2004-01-01

    According to the European Plant Protection Organization, the pinewood nematode (PWN), Bursaphelenchus xylophilus is a quarantine organism at the top of the list of the pathogenic species. PWN may be found in North America (Canada, USA and Mexico) and in East Asia (Japan, Korea, China and Taiwan) and has a highly destructive capability towards conifers, in a relatively short time, causing serious economic damage in Japan, China and Korea. This nematode surveying is extremely imp...

  2. Antagonistic Activities of Streptomyces against Root Knot Nematode of Kiwifruit

    Directory of Open Access Journals (Sweden)

    S. Bashiri

    2016-02-01

    Full Text Available Introduction: Iran is among the world leading kiwifruit producers with 2.816 ha cultivated and 31.567 tones production. Plant parasitic nematodes cause damages to a variety of agricultural crops throughout the world. Interest in biological control of nematodes has increased because of the need for alternative methods to fumigant and non-fumigant nematicides and overall improvement of IPM programs. Bacterial species with nematicidal activity have also been used with some success for controlling root-knot diseases, including Streptomyces spp., Serratia spp., Bacillus spp. and Pseudomonas spp. The goal of the current study was to isolate, identify and investigate the potential of local Streptomyces bacteria for controlling and reducing root-knot nematode population in the north of Iran. Materials and Methods: In order to evaluate the effect of antagonistic bacteria on control of root-knot nematode of Kiwifruit, 100 isolates of bacteria were collected from Kiwifruit rhizosphere in the north of Iran and screened for pigmented microorganisms especially Streptomyces by applying standard serial dilution plate technique, using starch casein nitrate agar and glycerol asparagine agar. Morphological characterizations were achieved by the microscopic method. The microscopic characterization was done by cover slip culture method. The mycelium structure, color and arrangement of conidiospore and arthrospore on the mycelium were observed through the oil immersion (100X. The observed structure was compared with Bergey’s Manual of Determinative Bacteriology and the organism was identified. Various biochemical tests performed for the identification of the potent isolates are as follows: casein hydrolysis, starch hydrolysis, urea hydrolysis, esculin hydrolysis, acid production from sugar, NaCl resistance, temperature tolerance. Soil samples (100g were collected, and then processed for nematode egg and larvae extraction Hussey method. The suspension was pipetted

  3. The novel cyst nematode effector protein 19C07 interacts with the Arabidopsis auxin influx transporter LAX3 to control feeding site development.

    Science.gov (United States)

    Lee, Chris; Chronis, Demosthenis; Kenning, Charlotte; Peret, Benjamin; Hewezi, Tarek; Davis, Eric L; Baum, Thomas J; Hussey, Richard; Bennett, Malcolm; Mitchum, Melissa G

    2011-02-01

    Plant-parasitic cyst nematodes penetrate plant roots and transform cells near the vasculature into specialized feeding sites called syncytia. Syncytia form by incorporating neighboring cells into a single fused cell by cell wall dissolution. This process is initiated via injection of esophageal gland cell effector proteins from the nematode stylet into the host cell. Once inside the cell, these proteins may interact with host proteins that regulate the phytohormone auxin, as cellular concentrations of auxin increase in developing syncytia. Soybean cyst nematode (Heterodera glycines) Hg19C07 is a novel effector protein expressed specifically in the dorsal gland cell during nematode parasitism. Here, we describe its ortholog in the beet cyst nematode (Heterodera schachtii), Hs19C07. We demonstrate that Hs19C07 interacts with the Arabidopsis (Arabidopsis thaliana) auxin influx transporter LAX3. LAX3 is expressed in cells overlying lateral root primordia, providing auxin signaling that triggers the expression of cell wall-modifying enzymes, allowing lateral roots to emerge. We found that LAX3 and polygalacturonase, a LAX3-induced cell wall-modifying enzyme, are expressed in the developing syncytium and in cells to be incorporated into the syncytium. We observed no decrease in H. schachtii infectivity in aux1 and lax3 single mutants. However, a decrease was observed in both the aux1lax3 double mutant and the aux1lax1lax2lax3 quadruple mutant. In addition, ectopic expression of 19C07 was found to speed up lateral root emergence. We propose that Hs19C07 most likely increases LAX3-mediated auxin influx and may provide a mechanism for cyst nematodes to modulate auxin flow into root cells, stimulating cell wall hydrolysis for syncytium development.

  4. Competition between endoparasitic nematodes and effect on biomass of Ammophila arenaria (marram grass) as affected by timing of inoculation and plant age

    NARCIS (Netherlands)

    Brinkman, E.P.; Duyts, H.; Van der Putten, W.H.

    2005-01-01

    We studied the effects of intra- and interspecific competition on the abundance of endoparasitic nematodes and assessed the consequences for biomass production of the natural dune grass Ammophila arenaria. Pratylenchus penetrans was limited by intraspecific competition and it suppressed the

  5. Further Screening of Entomopathogenic Fungi and Nematodes as Control Agents for Drosophila suzukii

    Directory of Open Access Journals (Sweden)

    Andrew G. S. Cuthbertson

    2016-06-01

    Full Text Available Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B; Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p < 0.001 reduced population development of D. suzukii from infested berries. All nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed.

  6. Further Screening of Entomopathogenic Fungi and Nematodes as Control Agents for Drosophila suzukii.

    Science.gov (United States)

    Cuthbertson, Andrew G S; Audsley, Neil

    2016-06-09

    Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B); Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed.

  7. Microbiomes associated with infective stages of root-knot and lesion nematodes in soil.

    Directory of Open Access Journals (Sweden)

    Ahmed Elhady

    Full Text Available Endoparasitic root-knot (Meloidogyne spp. and lesion (Pratylenchus spp. nematodes cause considerable damage in agriculture. Before they invade roots to complete their life cycle, soil microbes can attach to their cuticle or surface coat and antagonize the nematode directly or by induction of host plant defenses. We investigated whether the nematode-associated microbiome in soil differs between infective stages of Meloidogyne incognita and Pratylenchus penetrans, and whether it is affected by variation in the composition of microbial communities among soils. Nematodes were incubated in suspensions of five organically and two integrated horticultural production soils, recovered by sieving and analyzed for attached bacteria and fungi after washing off loosely adhering microbes. Significant effects of the soil type and nematode species on nematode-associated fungi and bacteria were revealed as analyzed by community profiling using denaturing gradient gel electrophoresis. Attached microbes represented a small specific subset of the soil microbiome. Two organic soils had very similar bacterial and fungal community profiles, but one of them was strongly suppressive towards root-knot nematodes. They were selected for deep amplicon sequencing of bacterial 16S rRNA genes and fungal ITS. Significant differences among the microbiomes associated with the two species in both soils suggested specific surface epitopes. Among the 28 detected bacterial classes, Betaproteobacteria, Bacilli and Actinobacteria were the most abundant. The most frequently detected fungal genera were Malassezia, Aspergillus and Cladosporium. Attached microbiomes did not statistically differ between these two soils. However, Malassezia globosa and four fungal species of the family Plectosphaerellaceae, and the bacterium Neorhizobium galegae were strongly enriched on M. incognita in the suppressive soil. In conclusion, the highly specific attachment of microbes to infective stages of

  8. A Nematode Calreticulin, Rs-CRT, Is a Key Effector in Reproduction and Pathogenicity of Radopholus similis.

    Science.gov (United States)

    Li, Yu; Wang, Ke; Xie, Hui; Wang, Yan-Tao; Wang, Dong-Wei; Xu, Chun-Lin; Huang, Xin; Wang, De-Sen

    2015-01-01

    Radopholus similis is a migratory plant-parasitic nematode that causes severe damage to many agricultural and horticultural crops. Calreticulin (CRT) is a Ca2+-binding multifunctional protein that plays key roles in the parasitism, immune evasion, reproduction and pathogenesis of many animal parasites and plant nematodes. Therefore, CRT is a promising target for controlling R. similis. In this study, we obtained the full-length sequence of the CRT gene from R. similis (Rs-crt), which is 1,527-bp long and includes a 1,206-bp ORF that encodes 401 amino acids. Rs-CRT and Mi-CRT from Meloidogyne incognita showed the highest similarity and were grouped on the same branch of the phylogenetic tree. Rs-crt is a multi-copy gene that is expressed in the oesophageal glands and gonads of females, the gonads of males, the intestines of juveniles and the eggs of R. similis. The highest Rs-crt expression was detected in females, followed by juveniles, eggs and males. The reproductive capability and pathogenicity of R. similis were significantly reduced after treatment with Rs-crt dsRNA for 36 h. Using plant-mediated RNAi, we confirmed that Rs-crt expression was significantly inhibited in the nematodes, and resistance to R. similis was significantly improved in transgenic tomato plants. Plant-mediated RNAi-induced silencing of Rs-crt could be effectively transmitted to the F2 generation of R. similis; however, the silencing effect of Rs-crt induced by in vitro RNAi was no longer detectable in F1 and F2 nematodes. Thus, Rs-crt is essential for the reproduction and pathogenicity of R. similis.

  9. A Nematode Calreticulin, Rs-CRT, Is a Key Effector in Reproduction and Pathogenicity of Radopholus similis.

    Directory of Open Access Journals (Sweden)

    Yu Li

    Full Text Available Radopholus similis is a migratory plant-parasitic nematode that causes severe damage to many agricultural and horticultural crops. Calreticulin (CRT is a Ca2+-binding multifunctional protein that plays key roles in the parasitism, immune evasion, reproduction and pathogenesis of many animal parasites and plant nematodes. Therefore, CRT is a promising target for controlling R. similis. In this study, we obtained the full-length sequence of the CRT gene from R. similis (Rs-crt, which is 1,527-bp long and includes a 1,206-bp ORF that encodes 401 amino acids. Rs-CRT and Mi-CRT from Meloidogyne incognita showed the highest similarity and were grouped on the same branch of the phylogenetic tree. Rs-crt is a multi-copy gene that is expressed in the oesophageal glands and gonads of females, the gonads of males, the intestines of juveniles and the eggs of R. similis. The highest Rs-crt expression was detected in females, followed by juveniles, eggs and males. The reproductive capability and pathogenicity of R. similis were significantly reduced after treatment with Rs-crt dsRNA for 36 h. Using plant-mediated RNAi, we confirmed that Rs-crt expression was significantly inhibited in the nematodes, and resistance to R. similis was significantly improved in transgenic tomato plants. Plant-mediated RNAi-induced silencing of Rs-crt could be effectively transmitted to the F2 generation of R. similis; however, the silencing effect of Rs-crt induced by in vitro RNAi was no longer detectable in F1 and F2 nematodes. Thus, Rs-crt is essential for the reproduction and pathogenicity of R. similis.

  10. Basic and applied research: Entomopathogenic nematodes

    Science.gov (United States)

    Entomopathogenic nematodes in the genera Heterorhabditis and Steinernema kill arthropods with the aid of their bacterial symbionts. These nematodes are potent microbial control agents that have been widely commercialized for control of economically important insect pests. Biocontrol efficacy relies...

  11. Differential Change Patterns of Main Antimicrobial Peptide Genes During Infection of Entomopathogenic Nematodes and Their Symbiotic Bacteria.

    Science.gov (United States)

    Darsouei, Reyhaneh; Karimi, Javad; Ghadamyari, Mohammad; Hosseini, Mojtaba

    2017-08-01

    The expression of antimicrobial peptides (AMPs) as the main humoral defense reactions of insects during infection by entomopathogenic nematodes (EPNs) and their symbiont is addressed herein. Three AMPs, attacin, cecropin, and spodoptericin, were evaluated in the fifth instar larvae of Spodoptera exigua Hübner (beet armyworm) when challenged with Steinernema carpocapsae or Heterorhabditis bacteriophora. The results indicated that attacin was expressed to a greater extent than either cecropin or spodoptericin. While spodoptericin was expressed to a much lesser extent, this AMP was induced against Gram-positive bacteria, and thus not expressed after penetration of Xenorhabdus nematophila and Photorhabdus luminescens. Attacin and cecropin in the larvae treated with S. carpocapsae at 8 hr post-injection (PI) attained the maximum expression levels and were 138.42-fold and 65.84-fold greater than those of larvae infected with H. bacteriophora, respectively. Generally, the ability of H. bacteriophora to suppress attacin, cecropin, and spodoptericin was greater than that of S. carpocapsae. According to the results, the expression of AMPs by Sp. exigua larvae against S. carpocapsae was determined in the 4 statuses of monoxenic nematode, axenic nematode, live symbiotic bacterium, and dead symbiotic bacterium. The expression of attacin in larvae treated with a monoxenic nematode and live bacterium at 8 and 2 hr PI, respectively, were increased to the maximum amount. Live X. nematophila was the strongest agent for the suppression of attacin. The expression of cecropin against monoxenic nematodes and live symbiotic bacteria at 8 and 4 hr PI, respectively, reached the maximum amount while the expression levels of attacin and cecropin for axenic nematodes were lesser and stable. The results highlighted that the ability of P. luminescens in AMPs suppression was much more than X. nematophila. The results also showed that the effect of symbiotic bacterium in suppressing attacin and

  12. Entomopathogenic nematodes for the biocontrol of ticks.

    Science.gov (United States)

    Samish, M; Glazer, I

    2001-08-01

    Entomopathogenic steinemematid and heterorhabditid nematodes are increasingly used to control insect pests of economically important crops. Laboratory and field simulation trials show that ticks are also susceptible to these nematodes. The authors review the potential of entomogenous nematodes for the control of ticks.

  13. Transgenic potatoes for potato cyst nematode control can replace pesticide use without impact on soil quality.

    Science.gov (United States)

    Green, Jayne; Wang, Dong; Lilley, Catherine J; Urwin, Peter E; Atkinson, Howard J

    2012-01-01

    Current and future global crop yields depend upon soil quality to which soil organisms make an important contribution. The European Union seeks to protect European soils and their biodiversity for instance by amending its Directive on pesticide usage. This poses a challenge for control of Globodera pallida (a potato cyst nematode) for which both natural resistance and rotational control are inadequate. One approach of high potential is transgenically based resistance. This work demonstrates the potential in the field of a new transgenic trait for control of G. pallida that suppresses root invasion. It also investigates its impact and that of a second transgenic trait on the non-target soil nematode community. We establish that a peptide that disrupts chemoreception of nematodes without a lethal effect provides resistance to G. pallida in both a containment and a field trial when precisely targeted under control of a root tip-specific promoter. In addition we combine DNA barcoding and quantitative PCR to recognise nematode genera from soil samples without microscope-based observation and use the method for nematode faunal analysis. This approach establishes that the peptide and a cysteine proteinase inhibitor that offer distinct bases for transgenic plant resistance to G. pallida do so without impact on the non-target nematode soil community.

  14. Transgenic potatoes for potato cyst nematode control can replace pesticide use without impact on soil quality.

    Directory of Open Access Journals (Sweden)

    Jayne Green

    Full Text Available Current and future global crop yields depend upon soil quality to which soil organisms make an important contribution. The European Union seeks to protect European soils and their biodiversity for instance by amending its Directive on pesticide usage. This poses a challenge for control of Globodera pallida (a potato cyst nematode for which both natural resistance and rotational control are inadequate. One approach of high potential is transgenically based resistance. This work demonstrates the potential in the field of a new transgenic trait for control of G. pallida that suppresses root invasion. It also investigates its impact and that of a second transgenic trait on the non-target soil nematode community. We establish that a peptide that disrupts chemoreception of nematodes without a lethal effect provides resistance to G. pallida in both a containment and a field trial when precisely targeted under control of a root tip-specific promoter. In addition we combine DNA barcoding and quantitative PCR to recognise nematode genera from soil samples without microscope-based observation and use the method for nematode faunal analysis. This approach establishes that the peptide and a cysteine proteinase inhibitor that offer distinct bases for transgenic plant resistance to G. pallida do so without impact on the non-target nematode soil community.

  15. Rhizosphere Colonization and Control of Meloidogyne spp. by Nematode-trapping Fungi

    Science.gov (United States)

    Persson, Christina; Jansson, Hans-Börje

    1999-01-01

    The ability of nematode-trapping fungi to colonize the rhizosphere of crop plants has been suggested to be an important factor in biological control of root-infecting nematodes. In this study, rhizosphere colonization was evaluated for 38 isolates of nematode-trapping fungi representing 11 species. In an initial screen, Arthrobotrys dactyloides, A. superba, and Monacrosporium ellipsosporum were most frequently detected in the tomato rhizosphere. In subsequent pot experiments these fungi and the non-root colonizing M. geophyropagum were introduced to soil in a sodium alginate matrix, and further tested both for establishment in the tomato rhizosphere and suppression of root-knot nematodes. The knob-forming M. ellipsosporum showed a high capacity to colonize the rhizosphere both in the initial screen and the pot experiments, with more than twice as many fungal propagules in the rhizosphere as in the root-free soil. However, neither this fungus nor the other nematode-trapping fungi tested reduced nematode damage to tomato plants. PMID:19270886

  16. Lipopolysaccharides of Rhizobium etli strain G12 act in potato roots as an inducing agent of systemic resistance to infection by the cyst nematode Globodera pallida.

    Science.gov (United States)

    Reitz, M; Rudolph, K; Schröder, I; Hoffmann-Hergarten, S; Hallmann, J; Sikora, R A

    2000-08-01

    Recent studies have shown that living and heat-killed cells of the rhizobacterium Rhizobium etli strain G12 induce in potato roots systemic resistance to infection by the potato cyst nematode Globodera pallida. To better understand the mechanisms of induced resistance, we focused on identifying the inducing agent. Since heat-stable bacterial surface carbohydrates such as exopolysaccharides (EPS) and lipopolysaccharides (LPS) are essential for recognition in the symbiotic interaction between Rhizobium and legumes, their role in the R. etli-potato interaction was studied. EPS and LPS were extracted from bacterial cultures, applied to potato roots, and tested for activity as an inducer of plant resistance to the plant-parasitic nematode. Whereas EPS did not affect G. pallida infection, LPS reduced nematode infection significantly in concentrations as low as 1 and 0.1 mg ml(-1). Split-root experiments, guaranteeing a spatial separation of inducing agent and challenging pathogen, showed that soil treatments of one half of the root system with LPS resulted in a highly significant (up to 37%) systemic induced reduction of G. pallida infection of potato roots in the other half. The results clearly showed that LPS of R. etli G12 act as the inducing agent of systemic resistance in potato roots.

  17. Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate.

    Science.gov (United States)

    Palomares-Rius, Juan Emilio; Hedley, Pete; Cock, Peter J A; Morris, Jenny A; Jones, John T; Blok, Vivian C

    2016-01-01

    Plant-parasitic nematodes (PPN) need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN) (Globodera pallida and G. rostochiensis) are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD) using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD) treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium), while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules).

  18. A major QTL corresponding to the Rk locus for resistance to root-knot nematodes in cowpea (Vigna unguiculata L. Walp.).

    Science.gov (United States)

    Huynh, Bao-Lam; Matthews, William C; Ehlers, Jeffrey D; Lucas, Mitchell R; Santos, Jansen R P; Ndeve, Arsenio; Close, Timothy J; Roberts, Philip A

    2016-01-01

    Genome resolution of a major QTL associated with the Rk locus in cowpea for resistance to root-knot nematodes has significance for plant breeding programs and R gene characterization. Cowpea (Vigna unguiculata L. Walp.) is a susceptible host of root-knot nematodes (Meloidogyne spp.) (RKN), major plant-parasitic pests in global agriculture. To date, breeding for host resistance in cowpea has relied on phenotypic selection which requires time-consuming and expensive controlled infection assays. To facilitate marker-based selection, we aimed to identify and map quantitative trait loci (QTL) conferring the resistance trait. One recombinant inbred line (RIL) and two F2:3 populations, each derived from a cross between a susceptible and a resistant parent, were genotyped with genome-wide single nucleotide polymorphism (SNP) markers. The populations were screened in the field for root-galling symptoms and/or under growth-chamber conditions for nematode reproduction levels using M. incognita and M. javanica biotypes. One major QTL was mapped consistently on linkage group VuLG11 of each population. By genotyping additional cowpea lines and near-isogenic lines derived from conventional backcrossing, we confirmed that the detected QTL co-localized with the genome region associated with the Rk locus for RKN resistance that has been used in conventional breeding for many decades. This chromosomal location defined with flanking markers will be a valuable target in marker-assisted breeding and for positional cloning of genes controlling RKN resistance.

  19. Gene expression changes in diapause or quiescent potato cyst nematode, Globodera pallida, eggs after hydration or exposure to tomato root diffusate

    Directory of Open Access Journals (Sweden)

    Juan Emilio Palomares-Rius

    2016-02-01

    Full Text Available Plant-parasitic nematodes (PPN need to be adapted to survive in the absence of a suitable host or in hostile environmental conditions. Various forms of developmental arrest including hatching inhibition and dauer stages are used by PPN in order to survive these conditions and spread to other areas. Potato cyst nematodes (PCN (Globodera pallida and G. rostochiensis are frequently in an anhydrobiotic state, with unhatched nematode persisting for extended periods of time inside the cyst in the absence of the host. This paper shows fundamental changes in the response of quiescent and diapaused eggs of G. pallida to hydration and following exposure to tomato root diffusate (RD using microarray gene expression analysis encompassing a broad set of genes. For the quiescent eggs, 547 genes showed differential expression following hydration vs. hydratation and RD (H-RD treatment whereas 708 genes showed differential regulation for the diapaused eggs following these treatments. The comparison between hydrated quiescent and diapaused eggs showed marked differences, with 2,380 genes that were differentially regulated compared with 987 genes following H-RD. Hydrated quiescent and diapaused eggs were markedly different indicating differences in adaptation for long-term survival. Transport activity is highly up-regulated following H-RD and few genes were coincident between both kinds of eggs. With the quiescent eggs, the majority of genes were related to ion transport (mainly sodium, while the diapaused eggs showed a major diversity of transporters (amino acid transport, ion transport, acetylcholine or other molecules.

  20. Development of enzyme linked immunosorbent assay (ELISA) for the detection of root-knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Kapur-Ghai, J; Kaur, M; Goel, P

    2014-09-01

    Root-knot nematodes (Meloidogyne incognita) are obligate, sedentary plant endoparasites that are extremely polyphagous in nature and cause severe economic losses in agriculture. Hence, it is essential to control the parasite at an early stage. For any control strategy to be effective, an early and accurate diagnosis is of paramount importance. Immunoassays have the inherent advantages of sensitivity and specificity; have the potential to identify and quantify these plant-parasitic nematodes. Hence, in the present studies, enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of M.incognita antigens. First an indirect ELISA was developed for detection and titration of anti-M.incognita antibodies. Results indicated as high as 320 K titre of the antisera. Finally competitive inhibition ELISA was developed employing these anti-M.incognita antibodies for detection of M.incognita antigens. Sensitivity of ELISA was 10 fg. Competitive inhibition ELISA developed in the present studies has the potential of being used as an easy, rapid, specific and sensitive diagnostic tool for the detection of M.incognita infection.

  1. Predator-prey interactions of nematode-trapping fungi and nematodes: both sides of the coin.

    Science.gov (United States)

    Vidal-Diez de Ulzurrun, Guillermo; Hsueh, Yen-Ping

    2018-05-01

    Nematode-trapping fungi develop complex trapping devices to capture and consume nematodes. The dynamics of these organisms is especially important given the pathogenicity of nematodes and, consequently, the potential application of nematode-trapping fungi as biocontrol agents. Furthermore, both the nematodes and nematode-trapping fungi can be easily grown in laboratories, making them a unique manipulatable predator-prey system to study their coevolution. Several different aspects of these fungi have been studied, such as their genetics and the different factors triggering trap formation. In this review, we use the nematode-trapping fungus Arthrobotrys oligospora (which forms adhesive nets) as a model to describe the trapping process. We divide this process into several stages; namely attraction, recognition, trap formation, adhesion, penetration, and digestion. We summarize the latest findings in the field and current knowledge on the interactions between nematodes and nematode-trapping fungi, representing both sides of the predator-prey interaction.

  2. Olfactory circuits and behaviors of nematodes.

    Science.gov (United States)

    Rengarajan, Sophie; Hallem, Elissa A

    2016-12-01

    Over one billion people worldwide are infected with parasitic nematodes. Many parasitic nematodes actively search for hosts to infect using volatile chemical cues, so understanding the olfactory signals that drive host seeking may elucidate new pathways for preventing infections. The free-living nematode Caenorhabditis elegans is a powerful model for parasitic nematodes: because sensory neuroanatomy is conserved across nematode species, an understanding of the microcircuits that mediate olfaction in C. elegans may inform studies of olfaction in parasitic nematodes. Here we review circuit mechanisms that allow C. elegans to respond to odorants, gases, and pheromones. We also highlight work on the olfactory behaviors of parasitic nematodes that lays the groundwork for future studies of their olfactory microcircuits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Immunity to gastrointestinal nematode infections

    DEFF Research Database (Denmark)

    Sorobetea, D.; Svensson Frej, M.; Grencis, R.

    2018-01-01

    Numerous species of nematodes have evolved to inhabit the gastrointestinal tract of animals and humans, with over a billion of the world's population infected with at least one species. These large multicellular pathogens present a considerable and complex challenge to the host immune system give...

  4. Simultaneous exposure of nematophagous fungi, entomopathogenic nematodes and entomopathogenic fungi can modulate belowground insect pest control.

    Science.gov (United States)

    Bueno-Pallero, Francisco Ángel; Blanco-Pérez, Rubén; Dionísio, Lídia; Campos-Herrera, Raquel

    2018-05-01

    Entomopathogenic nematodes (EPNs) and fungi (EPF) are well known biological control agents (BCAs) against insect pests. Similarly, the nematophagous fungi (NF) are considered good BCA candidates for controlling plant parasitic nematodes. Because NF can employ EPNs as food and interact with EPF, we speculate that the simultaneous application of EPNs and EPF might result in higher insect mortality, whereas the triple species combination with NF will reduce the EPN and EPF activity by predation or inhibition. Here we evaluated single, dual (EPN + EPF, EPF + NF, EPN + NF) and triple (EPN + EPF + NF) combinations of one EPN, Steinernema feltiae (Rhabditida: Steinernematidae), one EPF, Beauveria bassiana (Hypocreales: Clavicipitaceae), and two NF, Arthrobotrys musiformis (Orbiliales: Orbiliaceae) and Purpureocillium lilacinum (Hypocreales: Ophiocordycipitaceae) under laboratory conditions. First, we showed that EPF reduced the growth rate of NF and vice versa when combined in both rich and limiting media, suggesting a negative interaction when combining both fungi. Three different fungal applications (contact with mycelia-conidia, immersion in conidial suspension, and injection of conidial suspension) were tested in single, dual and triple species combinations, evaluating Galleria mellonella (Lepidoptera: Pyralidae) larval mortality and time to kill. When mycelia was presented, the EPF appeared to be the dominant in combined treatments, whereas in immersion exposure was the EPN. In both types of exposure, NF alone did not produce any effect on larvae. However, when A. musiformis was injected, it produced larval mortalities >70% in the same time span as EPN. Overall, additive effects dominated the dual and triple combinations, with the exception of injection method, where synergisms occurred for both NF species combined with EPN + EPF. This study illustrates how differences in species combination and timing of fungal arrival can modulate the action

  5. The genome of the yellow potato cyst nematode, Globodera rostochiensis, reveals insights into the basis of parasitism and virulence.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Laetsch, Dominik R; Thorpe, Peter; Lilley, Catherine J; Danchin, Etienne G J; Da Rocha, Martine; Rancurel, Corinne; Holroyd, Nancy E; Cotton, James A; Szitenberg, Amir; Grenier, Eric; Montarry, Josselin; Mimee, Benjamin; Duceppe, Marc-Olivier; Boyes, Ian; Marvin, Jessica M C; Jones, Laura M; Yusup, Hazijah B; Lafond-Lapalme, Joël; Esquibet, Magali; Sabeh, Michael; Rott, Michael; Overmars, Hein; Finkers-Tomczak, Anna; Smant, Geert; Koutsovoulos, Georgios; Blok, Vivian; Mantelin, Sophie; Cock, Peter J A; Phillips, Wendy; Henrissat, Bernard; Urwin, Peter E; Blaxter, Mark; Jones, John T

    2016-06-10

    The yellow potato cyst nematode, Globodera rostochiensis, is a devastating plant pathogen of global economic importance. This biotrophic parasite secretes effectors from pharyngeal glands, some of which were acquired by horizontal gene transfer, to manipulate host processes and promote parasitism. G. rostochiensis is classified into pathotypes with different plant resistance-breaking phenotypes. We generate a high quality genome assembly for G. rostochiensis pathotype Ro1, identify putative effectors and horizontal gene transfer events, map gene expression through the life cycle focusing on key parasitic transitions and sequence the genomes of eight populations including four additional pathotypes to identify variation. Horizontal gene transfer contributes 3.5 % of the predicted genes, of which approximately 8.5 % are deployed as effectors. Over one-third of all effector genes are clustered in 21 putative 'effector islands' in the genome. We identify a dorsal gland promoter element motif (termed DOG Box) present upstream in representatives from 26 out of 28 dorsal gland effector families, and predict a putative effector superset associated with this motif. We validate gland cell expression in two novel genes by in situ hybridisation and catalogue dorsal gland promoter element-containing effectors from available cyst nematode genomes. Comparison of effector diversity between pathotypes highlights correlation with plant resistance-breaking. These G. rostochiensis genome resources will facilitate major advances in understanding nematode plant-parasitism. Dorsal gland promoter element-containing effectors are at the front line of the evolutionary arms race between plant and parasite and the ability to predict gland cell expression a priori promises rapid advances in understanding their roles and mechanisms of action.

  6. In planta processing and glycosylation of a nematode CLAVATA3/ENDOSPERM SURROUNDING REGION-like effector and its interaction with a host CLAVATA2-like receptor to promote parasitism.

    Science.gov (United States)

    Chen, Shiyan; Lang, Ping; Chronis, Demosthenis; Zhang, Sheng; De Jong, Walter S; Mitchum, Melissa G; Wang, Xiaohong

    2015-01-01

    Like other biotrophic plant pathogens, plant-parasitic nematodes secrete effector proteins into host cells to facilitate infection. Effector proteins that mimic plant CLAVATA3/ENDOSPERM SURROUNDING REGION-related (CLE) proteins have been identified in several cyst nematodes, including the potato cyst nematode (PCN); however, the mechanistic details of this cross-kingdom mimicry are poorly understood. Plant CLEs are posttranslationally modified and proteolytically processed to function as bioactive ligands critical to various aspects of plant development. Using ectopic expression coupled with nanoliquid chromatography-tandem mass spectrometry analysis, we show that the in planta mature form of proGrCLE1, a multidomain CLE effector secreted by PCN during infection, is a 12-amino acid arabinosylated glycopeptide (named GrCLE1-1Hyp4,7g) with striking structural similarity to mature plant CLE peptides. This glycopeptide is more resistant to hydrolytic degradation and binds with higher affinity to a CLAVATA2-like receptor (StCLV2) from potato (Solanum tuberosum) than its nonglycosylated forms. We further show that StCLV2 is highly up-regulated at nematode infection sites and that transgenic potatoes with reduced StCLV2 expression are less susceptible to PCN infection, indicating that interference of the CLV2-mediated signaling pathway confers nematode resistance in crop plants. These results strongly suggest that phytonematodes have evolved to utilize host cellular posttranslational modification and processing machinery for the activation of CLE effectors following secretion into plant cells and highlight the significance of arabinosylation in regulating nematode CLE effector activity. Our finding also provides evidence that multidomain CLEs are modified and processed similarly to single-domain CLEs, adding new insight into CLE maturation in plants. © 2015 American Society of Plant Biologists. All Rights Reserved.

  7. In Planta Processing and Glycosylation of a Nematode CLAVATA3/ENDOSPERM SURROUNDING REGION-Like Effector and Its Interaction with a Host CLAVATA2-Like Receptor to Promote Parasitism1[OPEN

    Science.gov (United States)

    Chen, Shiyan; Lang, Ping; Chronis, Demosthenis; Zhang, Sheng; De Jong, Walter S.; Mitchum, Melissa G.

    2015-01-01

    Like other biotrophic plant pathogens, plant-parasitic nematodes secrete effector proteins into host cells to facilitate infection. Effector proteins that mimic plant CLAVATA3/ENDOSPERM SURROUNDING REGION-related (CLE) proteins have been identified in several cyst nematodes, including the potato cyst nematode (PCN); however, the mechanistic details of this cross-kingdom mimicry are poorly understood. Plant CLEs are posttranslationally modified and proteolytically processed to function as bioactive ligands critical to various aspects of plant development. Using ectopic expression coupled with nanoliquid chromatography-tandem mass spectrometry analysis, we show that the in planta mature form of proGrCLE1, a multidomain CLE effector secreted by PCN during infection, is a 12-amino acid arabinosylated glycopeptide (named GrCLE1-1Hyp4,7g) with striking structural similarity to mature plant CLE peptides. This glycopeptide is more resistant to hydrolytic degradation and binds with higher affinity to a CLAVATA2-like receptor (StCLV2) from potato (Solanum tuberosum) than its nonglycosylated forms. We further show that StCLV2 is highly up-regulated at nematode infection sites and that transgenic potatoes with reduced StCLV2 expression are less susceptible to PCN infection, indicating that interference of the CLV2-mediated signaling pathway confers nematode resistance in crop plants. These results strongly suggest that phytonematodes have evolved to utilize host cellular posttranslational modification and processing machinery for the activation of CLE effectors following secretion into plant cells and highlight the significance of arabinosylation in regulating nematode CLE effector activity. Our finding also provides evidence that multidomain CLEs are modified and processed similarly to single-domain CLEs, adding new insight into CLE maturation in plants. PMID:25416475

  8. The interactive effect of entomopathogenic nematode, Steinernema carpocapsae (Weiser) and gamma radiation ori callosobruchus maculatus (F.) and their biochemical Effects

    International Nuclear Information System (INIS)

    EI-Orabi, M.N.; Slwfei, D.M.Y.; Amer, A.M.

    2007-01-01

    Cowpea weevil, Callosobruchus maculatus (F.) adults were infected with entomopathogenic nematodes, Steinernema carpocapsae (Weiser) for evaluating their potential for suppressing this insect pest. Morality percentage of un-irradiated C. maculatus infected with irradiated nematodes decreased at higher doses of gamma irradiation. The results generally Indicated that the reduction of mortality was directly related to gamma irradiation. The results indicated that infestation intensity decreased at higher doses of gamma irradiation when irradiated nematodes infected the irradiated or non-irradiated C. maculatus. Protein content of irradiated C. maculatus adults infected with nematodes showed a slight decrease by increasing radiation dose and time elapsed from infection. Comparing the protein bands at different time intervals for all tested dosage used showed absence of some bands and reduction in the intensity of the others

  9. Biocontrol: Fungal Parasites of Female Cyst Nematodes

    OpenAIRE

    Kerry, Brian

    1980-01-01

    Three species of fungi, Catenaria auxiliarls (Kühn) Tribe, Nematophthora gynophila Kerry and Crump, and a Lagenidiaceous fungus have been found attacking female cyst nematodes. All are zoosporic fungi which parasitize females on the root surface, cause the breakdown of the nematode cuticle, and prevent cyst formation. Their identification and some aspects of their biology are reviewed. N. gynophila is widespread in Britain and reduces populations of the cereal cyst nematode, Heterodera avenae...

  10. Epidemiological studies of nematodes in fishes

    International Nuclear Information System (INIS)

    Qamar, M.F.; Butt, K.; Qureshi, N.A.

    2014-01-01

    Three hundred fresh water fishes of six species were collected from six different fish farms of Lahore for the prevalence of nematodes. Out of 300 fishes examined, 12 were found to be infected with the helminthes, majority of them were isolated from the stomach and intestines. The following two species of nematodes were recorded; Capillaria spp. and Eustrongylides spp. The overall prevalence of intestinal nematodes was recorded as 4%(12/300). The prevalence of nematodes was recorded on monthly basis which ranged from 0-8%. The highest prevalence of nematodes was 8% (4/50) during March, while the lowest prevalence was noted in June 0%.Singharee (Sperata sawari) showed the maximum infestation of nematodes of 8% (4/50), whereas in Silver Carp (Hypopthaimichthys molitrix) minimum prevalence of nematode (0%) was noted. The prevalence of different nematode in a particular fish specie was also recorded, and it was stated that overall prevalence of capillaria spp. was 6% in Rahu (Labeo rohita) and Saul (Channa marullius). Similarly overall infestation of Eustrongylides sp. was recorded as 4% in Singharee (Sperata sawari) and Silver carp (Hypopthaimichthys molitrix). The nematode intensity might be linked with the genetic makeup, intestinal vigor, and other managemental and environmental factors. (author)

  11. root nematode control and crop yield

    African Journals Online (AJOL)

    SARAH

    2016-05-31

    May 31, 2016 ... The relationship between cost and benefit of the nematicide applications was also estimated. ... based on nematode threshold (100 nematodes per g of fresh root) which resulted in two applications; ..... France. Araya M, 2004. Situación actual del manejo de nematodos en banano (Musa AAA) y plátano.

  12. Benthic freshwater nematode community dynamics under conditions ...

    African Journals Online (AJOL)

    Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, ...

  13. Potato Cyst Nematode in East Java: Newly Infected Areas and Identification

    Directory of Open Access Journals (Sweden)

    Happy Cahya Nugrahana

    2017-12-01

    Full Text Available Potato Cyst Nematodes (PCN, Globodera rostochiensis has noted to be a devastated pest on potato in Indonesia. It is listed as the A2 pest by Plant Quarantine of Republik Indonesia, and it was also being a highly concerned plant parasitic nematode species worlwide. Therefore, both intensive and extensive surveys should be done to monitor the spread of PCN, especially in East Java as one of the centre of potato plantations in Indonesia. The aim of this study was to study the distribution of PCN in four potato plantations in East Java, i.e. Batu, Magetan, Probolinggo, and Pasuruan which were located between 1,205 to 2,063 m above the sea level. Extraction and isolation of cysts from soil samples was done using Baunacke method, and it was followed by identification of the nematodes using morphological and molecular approaches according to Baldwin and Mundo-Ocampo. The results showed that PCN was found on all sampling sites, i.e. Batu (Sumber Brantas, Jurang Kuali, Tunggangan, Junggo, Brakseng; Magetan (Dadi, Sarangan, Singolangu; Probolinggo (Tukul, Pandansari, Ledokombo, Sumberanom, Wonokerto, Ngadas, Pasuruan (Wonokerto, Tosari, Ledoksari, Ngadiwono. Magetan and Pasuruan were noted as new infested areas in East Java. Both morphological and molecular methods showed that the species found on all sites was Globodera rostochiensis.   Intisari Nematoda Sista Kentang (NSK, Globodera rostochiensis telah tercatat sebagai hama yang menghancurkan tanaman kentang di Indonesia. NSK terdaftar sebagai Organisme Pengganggu Tumbuhan Karantina golongan A2 oleh Badan Karantina Pertanian Republik Indonesia, dan juga merupakan spesies nematoda parasit tanaman yang sangat merugikan di seluruh dunia. Oleh karena itu, baik survei intensif maupun ekstensif harus dilakukan untuk memantau penyebaran NSK, terutama di Jawa Timur sebagai salah satu sentra tanaman kentang di Indonesia. Tujuan dari penelitian ini adalah untuk mempelajari distribusi NSK pada empat daerah sentra

  14. How do humans affect wildlife nematodes?

    Science.gov (United States)

    Weinstein, Sara B.; Lafferty, Kevin D.

    2015-01-01

    Human actions can affect wildlife and their nematode parasites. Species introductions and human-facilitated range expansions can create new host–parasite interactions. Novel hosts can introduce parasites and have the potential to both amplify and dilute nematode transmission. Furthermore, humans can alter existing nematode dynamics by changing host densities and the abiotic conditions that affect larval parasite survival. Human impacts on wildlife might impair parasites by reducing the abundance of their hosts; however, domestic animal production and complex life cycles can maintain transmission even when wildlife becomes rare. Although wildlife nematodes have many possible responses to human actions, understanding host and parasite natural history, and the mechanisms behind the changing disease dynamics might improve disease control in the few cases where nematode parasitism impacts wildlife.

  15. The simplest "field" methods for extractin of nematodes from plants, wood, insects and soil, with additional description how to keep extracted nematodes alive for a long time.

    Science.gov (United States)

    Ryss, A Yu

    2017-01-01

    The simplest modification of the dynamic extraction method using cottonwool filter based on the Baermann funnel principle, is described. This modification excludes the funnel because a great share of Sticky worms attach to sloping walls of a funnel and thus do not reach the collector Eppendorf tube. But the main principle of the Baermann funnel is used, I. e. sinking down of actively moving heavy narrow bodies via wide holes of filter and thus separating the active worms from passive non-Brownian moving substrate particles, which do not pass the filter and remain above it. This principle is illustrated because it has never been described before. In the proposed modification any sloping walls in the extraction paths are excluded and thus the probability to attach sticky nemotodes to walls is also excluded; only cylindrical equipment with abrupt vertical walls is used; procedures are extremely simplified to be user-friendly for beginners: only filter (cotton pads), Eppendorf tubes, plastic glasses and narrow PVC tubing are applied. The new simplified modification allows one to collect nematodes by non-professional workers, e. g. in Polar expeditions without microscopic study of results. As an addition, an efficient method to maintain extracted nematodes alive is proposed, using the "effect of water film" in foam rubber inside the Eppendorf tube. To maintain nematodes alive during several months it is recommended to suppress bacteria via addition of 0.2-0.4% formaldehyde solution and then keep the tube with nematodes in a refrigerator.

  16. Natural suppression of Meloidogyne incognita by Pasteuria penetrans in cotton

    Science.gov (United States)

    The endospore-forming bacterium Pasteuria penetrans is an obligate parasite of root-knot nematodes (Meloidogyne spp.). This bacterium is commonly found in agricultural soils and has been associated with suppression of Meloidogyne spp. In a field site naturally infested with both P. penetrans and M...

  17. An efficient cDNA-AFLP-based strategy for the identification of putative pathogenicity factors from the potato cyst nematode Globodera rostochiensis.

    Science.gov (United States)

    Qin, L; Overmars, H; Helder, J; Popeijus, H; van der Voort, J R; Groenink, W; van Koert, P; Schots, A; Bakker, J; Smant, G

    2000-08-01

    A new strategy has been designed to identify putative pathogenicity factors from the dorsal or subventral esophageal glands of the potato cyst nematode Globodera rostochiensis. Three independent criteria were used for selection. First, genes of interest should predominantly be expressed in infective second-stage juveniles, and not, or to a far lesser extent, in younger developmental stages. For this, gene expression profiles from five different developmental stages were generated with cDNA-AFLP (amplified fragment length polymorphism). Secondly, the mRNA corresponding to such a putative pathogenicity factor should predominantly be present in the esophageal glands of pre-parasitic juveniles. This was checked by in situ hybridization. As a third criterion, these proteinaceous factors should be preceded by a signal peptide for secretion. Expression profiles of more than 4,000 genes were generated and three up-regulated, dorsal gland-specific proteins preceded by signal peptide for secretion were identified. No dorsal gland genes have been cloned before from plant-parasitic nematodes. The partial sequence of these three factors, A4, A18, and A41, showed no significant homology to any known gene. Their presence in the dorsal glands of infective juveniles suggests that these proteins could be involved in feeding cell initiation, and not in migration in the plant root or in protection against plant defense responses. Finally, the applicability of this new strategy in other plant-microbe interactions is discussed.

  18. Spatial and temporal expression patterns of auxin response transcription factors in the syncytium induced by the beet cyst nematode Heterodera schachtii in Arabidopsis.

    Science.gov (United States)

    Hewezi, Tarek; Piya, Sarbottam; Richard, Geoffrey; Rice, J Hollis

    2014-09-01

    Plant-parasitic cyst nematodes induce the formation of a multinucleated feeding site in the infected root, termed the syncytium. Recent studies point to key roles of the phytohormone auxin in the regulation of gene expression and establishment of the syncytium. Nevertheless, information about the spatiotemporal expression patterns of the transcription factors that mediate auxin transcriptional responses during syncytium formation is limited. Here, we provide a gene expression map of 22 auxin response factors (ARFs) during the initiation, formation and maintenance stages of the syncytium induced by the cyst nematode Heterodera schachtii in Arabidopsis. We observed distinct and overlapping expression patterns of ARFs throughout syncytium development phases. We identified a set of ARFs whose expression is predominantly located inside the developing syncytium, whereas others are expressed in the neighbouring cells, presumably to initiate specific transcriptional programmes required for their incorporation within the developing syncytium. Our analyses also point to a role of certain ARFs in determining the maximum size of the syncytium. In addition, several ARFs were found to be highly expressed in fully developed syncytia, suggesting a role in maintaining the functional phenotype of mature syncytia. The dynamic distribution and overlapping expression patterns of various ARFs seem to be essential characteristics of ARF activity during syncytium development. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  19. Nematode communities in contaminated river sediments

    International Nuclear Information System (INIS)

    Heininger, Peter; Hoess, Sebastian; Claus, Evelyn; Pelzer, Juergen; Traunspurger, Walter

    2007-01-01

    Nematode communities of eight sites from three river catchments were investigated in terms of the genera composition, feeding types, and life-history strategists. The sampling sites showed a gradient of anthropogenic contamination with heavy metals and organic pollutants being important factors in differentiating the sites. Nematode community structure was related to sediment pollution and the hydro-morphological structure of the sampling sites. Heavily contaminated sites were characterized by communities with high relative abundances of omnivorous and predacious nematodes (Tobrilus, c-p 3; Mononchus, c-p 4), while sites with low to medium contamination were dominated by bacterivorous nematodes (Monhystera, Daptonema; c-p 2) or suction feeders (Dorylaimus, c-p 4). The relatively high Maturity Index values in the heavily polluted sites were surprising. Nematodes turned out to be a suitable organism group for monitoring sediment quality, with generic composition being the most accurate indicator for assessing differences in nematode community structure. - Nematode community structure of river sediments is related to pollution and site structure

  20. Nematode communities in contaminated river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Heininger, Peter [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Hoess, Sebastian [Ecossa - Ecological Sediment and Soil Assessment, Thierschstr. 43, 80538 Munich (Germany); Claus, Evelyn [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Pelzer, Juergen [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Traunspurger, Walter [University of Bielefeld, Department of Animal Ecology, Morgenbreede 45, 33615 Bielefeld (Germany)]. E-mail: traunspurger@uni-bielefeld.de

    2007-03-15

    Nematode communities of eight sites from three river catchments were investigated in terms of the genera composition, feeding types, and life-history strategists. The sampling sites showed a gradient of anthropogenic contamination with heavy metals and organic pollutants being important factors in differentiating the sites. Nematode community structure was related to sediment pollution and the hydro-morphological structure of the sampling sites. Heavily contaminated sites were characterized by communities with high relative abundances of omnivorous and predacious nematodes (Tobrilus, c-p 3; Mononchus, c-p 4), while sites with low to medium contamination were dominated by bacterivorous nematodes (Monhystera, Daptonema; c-p 2) or suction feeders (Dorylaimus, c-p 4). The relatively high Maturity Index values in the heavily polluted sites were surprising. Nematodes turned out to be a suitable organism group for monitoring sediment quality, with generic composition being the most accurate indicator for assessing differences in nematode community structure. - Nematode community structure of river sediments is related to pollution and site structure.

  1. influence of some types of Algerian soil on the development of rot-knot nematodes Meloidogyne incognita, M. javanica and M. arenaria (Tylenchida,Meloidogynidae)

    International Nuclear Information System (INIS)

    Hammach, M.

    2010-01-01

    Crops under greenhouses offer the possibility of vegetables production of high added value by focusing on earliness. They help to spread the availability timing of vegetables and fruits in the market throughout the year. However, these crops are subject to numerous attacks entailing heavy losses of yield quantity and quality. The plant parasitic nematodes especially rot-knot nematodes of the genus Meloidogyne are considered dangerous enemies of these cultures. The evolution study of these nematodes in different soil types allows one to compare the migration and movement of these nematodes in sandy soils considered as light soils, in clay soils heavy and intermediate silty clay soils. These soils have also rates of organic matter and a percentage of magnesium and calcium that might provide better conditions to the survival and migration of second stage larvae inoculated at a rate of 650 juveniles per pot of 24 cm in diameter where plants of melon Cucumis melo var. (Charentais) known to be susceptible to Meloidogyne was cultivated. The results for the population development of Meloidogyne, after a growing period of 3 months show an increase in the number of eggs, juvenile stages, inflated, swollen females and males in the 3 types of soil and that independently of clay fraction although clay soil may asphyxiate Meloidogyne. The development of the three species of Meloidogyne studied in these soils, the parameters taken into consideration (index of galls, which were 1.58, 1.75 and 1.5 for the sandy clay and the middle ground soils, vigour index and the evolution of populations of Meloidogyne and roots and soil as well as parameters related to production reveal the adaptation of these root-knot nematodes to the clay and sandy loam soils. At the end of culture, the final populations are important in the soils studied; 2680 for soil S. (sandy), 2272 for soil A (clay) and 2327 for soil I (intermediate) with a multiplication rate almost similar ( 4.12, 3.49 and 3

  2. The nematicidal effect of camellia seed cake on root-knot nematode Meloidogyne javanica of banana.

    Directory of Open Access Journals (Sweden)

    Xiujuan Yang

    Full Text Available Suppression of root-knot nematodes is crucially important for maintaining the worldwide development of the banana industry. Growing concerns about human and environmental safety have led to the withdrawal of commonly used nematicides and soil fumigants, thus motivating the development of alternative nematode management strategies. In this study, Meloidogyne javanica was isolated, and the nematicidal effect of Camellia seed cake on this pest was investigated. The results showed that in dish experiments, Camellia seed cake extracts under low concentration (2 g/L showed a strong nematicidal effect. After treatment for 72 h, the eggs of M. javanica were gradually dissolved, and the intestine of the juveniles gradually became indistinct. Nematicidal compounds, including saponins identified by HPLC-ESI-MS and 8 types of volatile compounds identified by GC-MS, exhibited effective nematicidal activities, especially 4-methylphenol. The pot experiments demonstrated that the application of Camellia seed cake suppressed M. javanica, and promoted the banana plant growth. This study explored an effective nematicidal agent for application in soil and revealed its potential mechanism of nematode suppression.

  3. IMPORTANT NEMATODE INFECTIONS IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Sri Oemijati

    2012-09-01

    Full Text Available At least 13 species of intestinal nematodes and 4 species of blood and tissue nematodes have been reported infecting man in Indonesia. Five species of intestinal nematodes are very common and highly prevalent, especially in the rural areas and slums of the big cities. Those species are Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, Trichuris trichiura and Oxyuris vermicularis, while Strongyloides stercoralis is disappearing. The prevalence of the soil transmitted helminths differs from place to place, depending on many factors such as the type of soil, human behaviour etc. Three species of lymph dwelling filarial worms are known to be endemic, the urban Wuchereria bancrofti is low endemic in Jakarta and a few other cities along the north coast of Java, with Culex incriminated as vector, high endemicity is found in Irian Jaya, where Anopheline mosquitoes act as vectors. Brugia malayi is widely distributed and is still highly endemic in many areas. The zoonotic type is mainly endemic in swampy areas, and has many species of Mansonia mosquitoes as vectors. B.timori so far has been found only in the south eastern part of the archipelago and has Anopheles barbirostris as vector. Human infections with animal parasites have been diagnosed properly only when adult stages were found either in autopsies or removed tissues. Cases of infections with A. caninum, A.braziliense, A.ceylanicum, Trichostrongylus colubriformis, T.axei and Oesophagostomum apiostomum have been desribed from autopsies, while infections with Gnathostoma spiningerum have been reported from removed tissues. Infections with the larval stages such as VLM, eosinophylic meningitis, occult filanasis and other could only be suspected, since the diagnosis was extremely difficult and based on the finding and identification of the parasite. Many cases of creeping eruption which might be caused by the larval stages of A.caninum and A.braziliense and Strongyloides stercoralis

  4. Suppressed Belief

    Directory of Open Access Journals (Sweden)

    Komarine Romdenh-Romluc

    2009-12-01

    Full Text Available Moran’s revised conception of conscious belief requires us to reconceptualise suppressed belief. The work of Merleau-Ponty offers a way to do this. His account of motor-skills allows us to understand suppressed beliefs as pre-reflective ways of dealing with the world.

  5. Different responses of soybean cyst nematode resistance between two RIL populations derived from Peking x 7605 under two ecological sites.

    Science.gov (United States)

    Li, Yongchun; Guo, Na; Zhao, Jinming; Zhou, Bin; Xu, Ran; Ding, Hui; Zhao, Weiguo; Gai, Junyi; Xing, Han

    2016-12-01

    The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a plant-parasitic nematode that feeds on the roots of soybean and most economically devastating pathogen of soybean (Glycine max (L.) Merr.) worldwide. Host plant resistance is the most effective control method. To understand SCN resistance in different environments, two recombinant-inbred lines (RILs) populations NJ(RN)P7 (217 F 2:8:11 lines) and JN(RN)P7 (248 F 2:7:9 lines) were developed from the cross of the cultivars Peking x 7605 in Nanjing and Jinan, respectively, and examined in this study. Peking is resistant to SCN race 1 (HG types 2.5.7), while 7605 is highly susceptible. Chi-square test of frequency distribution of families' female index (FI) showed that resistance to SCN was significantly different between NJ(RN)P7 and JN(RN)P7 populations. Three recessive genes conditioned the inheritance of resistance to SCN race 1 in both populations, but significant difference was detected for the mean of FI on two populations (DM= -16.68, P< 0.01). This indicated that natural selection may affect resistance to SCN. By analysing the variation of phenotype, the genetic structure of the two populations was determined to be different. The inheritance and variation of resistance were confirmed by simple sequence repeat (SSR) markers. For the two populations, 10 SSR markers showed polymorphism of resistant and susceptible DNA bulks. Some markers associated with the resistance of SCN races 1, 2, 3 and 5, and two markers, Satt163 and Satt309, reportedly related to rgh1 were detected both in NJ(RN)P7 and JN(RN)P7 populations. The results support the view that a disease acts as a selective force on plant resistance characteristics, which may alter the relative fitness of resistance alleles.

  6. Parasitic Nematode Interactions with Mammals and Plants

    NARCIS (Netherlands)

    Jasmer, D.P.; Goverse, A.; Smant, G.

    2003-01-01

    Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent

  7. WormBase: Annotating many nematode genomes.

    Science.gov (United States)

    Howe, Kevin; Davis, Paul; Paulini, Michael; Tuli, Mary Ann; Williams, Gary; Yook, Karen; Durbin, Richard; Kersey, Paul; Sternberg, Paul W

    2012-01-01

    WormBase (www.wormbase.org) has been serving the scientific community for over 11 years as the central repository for genomic and genetic information for the soil nematode Caenorhabditis elegans. The resource has evolved from its beginnings as a database housing the genomic sequence and genetic and physical maps of a single species, and now represents the breadth and diversity of nematode research, currently serving genome sequence and annotation for around 20 nematodes. In this article, we focus on WormBase's role of genome sequence annotation, describing how we annotate and integrate data from a growing collection of nematode species and strains. We also review our approaches to sequence curation, and discuss the impact on annotation quality of large functional genomics projects such as modENCODE.

  8. The potential signalling pathways which regulate surface changes induced by phytohormones in the potato cyst nematode (Globodera rostochiensis).

    Science.gov (United States)

    Akhkha, A; Curtis, R; Kennedy, M; Kusel, J

    2004-05-01

    It has been demonstrated that the surface lipophilicity of the plant-parasitic nematode Globodera rostochiensis decreases when infective larvae are exposed to the phytohormones indole-3-acetic acid (auxin) or kinetin (cytokinin). In the present study, it was shown that inhibition of phospholipase C (PLC) or phosphatidylinositol 3 kinase (PI3-kinase) reversed the effect of phytohormones on surface lipophilicity. The signalling pathway(s) involved in surface modification were investigated using 'caged' signalling molecules and stimulators or inhibitors of different signalling enzymes. Photolysis of the 'caged' signalling molecules, NPE-caged Ins 1,4,5-P3, NITR-5/AM or caged-cAMP to liberate IP3, Ca2+ or cAMP respectively, decreased the surface lipophilicity. Activation of adenylate cyclase also decreased the surface lipophilicity. In contrast, inhibition of PI3-kinase using Wortmannin, LY-294002 or Quercetin, and inhibition of PLC using U-73122 all increased the surface lipophilicity. Two possible signalling pathways involved in phytohormone-induced surface modification are proposed.

  9. Viruses and Phytoparasitic Nematodes of Cicer arietinum L.: Biotechnological Approaches in Interaction Studies and for Sustainable Control

    Science.gov (United States)

    Leonetti, Paola; Accotto, Gian Paolo; Hanafy, Moemen S.; Pantaleo, Vitantonio

    2018-01-01

    Cicer arietinum L. (chickpea) is the world's fourth most widely grown pulse. Chickpea seeds are a primary source of dietary protein for humans, and chickpea cultivation contributes to biological nitrogen fixation in the soil, given its symbiotic relationship with rhizobia. Therefore, chickpea cultivation plays a pivotal role in innovative sustainable models of agro-ecosystems inserted in crop rotation in arid and semi-arid environments for soil improvement and the reduction of chemical inputs. Indeed, the arid and semi-arid tropical zones of Africa and Asia have been primary areas of cultivation and diversification. Yet, nowadays, chickpea is gaining prominence in Canada, Australia, and South America where it constitutes a main ingredient in vegetarian and vegan diets. Viruses and plant parasitic nematodes (PPNs) have been considered to be of minor and local impact in primary areas of cultivation. However, the introduction of chickpea in new environments exposes the crop to these biotic stresses, compromising its yields. The adoption of high-throughput genomic technologies, including genome and transcriptome sequencing projects by the chickpea research community, has provided major insights into genome evolution as well as genomic architecture and domestication. This review summarizes the major viruses and PPNs that affect chickpea cultivation worldwide. We also present an overview of the current state of chickpea genomics. Accordingly, we explore the opportunities that genomics, post-genomics and novel editing biotechnologies are offering in order to understand chickpea diseases and stress tolerance and to design innovative control strategies. PMID:29599788

  10. Viruses and Phytoparasitic Nematodes of Cicer arietinum L.: Biotechnological Approaches in Interaction Studies and for Sustainable Control

    Directory of Open Access Journals (Sweden)

    Paola Leonetti

    2018-03-01

    Full Text Available Cicer arietinum L. (chickpea is the world's fourth most widely grown pulse. Chickpea seeds are a primary source of dietary protein for humans, and chickpea cultivation contributes to biological nitrogen fixation in the soil, given its symbiotic relationship with rhizobia. Therefore, chickpea cultivation plays a pivotal role in innovative sustainable models of agro-ecosystems inserted in crop rotation in arid and semi-arid environments for soil improvement and the reduction of chemical inputs. Indeed, the arid and semi-arid tropical zones of Africa and Asia have been primary areas of cultivation and diversification. Yet, nowadays, chickpea is gaining prominence in Canada, Australia, and South America where it constitutes a main ingredient in vegetarian and vegan diets. Viruses and plant parasitic nematodes (PPNs have been considered to be of minor and local impact in primary areas of cultivation. However, the introduction of chickpea in new environments exposes the crop to these biotic stresses, compromising its yields. The adoption of high-throughput genomic technologies, including genome and transcriptome sequencing projects by the chickpea research community, has provided major insights into genome evolution as well as genomic architecture and domestication. This review summarizes the major viruses and PPNs that affect chickpea cultivation worldwide. We also present an overview of the current state of chickpea genomics. Accordingly, we explore the opportunities that genomics, post-genomics and novel editing biotechnologies are offering in order to understand chickpea diseases and stress tolerance and to design innovative control strategies.

  11. Viruses and Phytoparasitic Nematodes of Cicer arietinum L.: Biotechnological Approaches in Interaction Studies and for Sustainable Control.

    Science.gov (United States)

    Leonetti, Paola; Accotto, Gian Paolo; Hanafy, Moemen S; Pantaleo, Vitantonio

    2018-01-01

    Cicer arietinum L. (chickpea) is the world's fourth most widely grown pulse. Chickpea seeds are a primary source of dietary protein for humans, and chickpea cultivation contributes to biological nitrogen fixation in the soil, given its symbiotic relationship with rhizobia. Therefore, chickpea cultivation plays a pivotal role in innovative sustainable models of agro-ecosystems inserted in crop rotation in arid and semi-arid environments for soil improvement and the reduction of chemical inputs. Indeed, the arid and semi-arid tropical zones of Africa and Asia have been primary areas of cultivation and diversification. Yet, nowadays, chickpea is gaining prominence in Canada, Australia, and South America where it constitutes a main ingredient in vegetarian and vegan diets. Viruses and plant parasitic nematodes (PPNs) have been considered to be of minor and local impact in primary areas of cultivation. However, the introduction of chickpea in new environments exposes the crop to these biotic stresses, compromising its yields. The adoption of high-throughput genomic technologies, including genome and transcriptome sequencing projects by the chickpea research community, has provided major insights into genome evolution as well as genomic architecture and domestication. This review summarizes the major viruses and PPNs that affect chickpea cultivation worldwide. We also present an overview of the current state of chickpea genomics. Accordingly, we explore the opportunities that genomics, post-genomics and novel editing biotechnologies are offering in order to understand chickpea diseases and stress tolerance and to design innovative control strategies.

  12. Fungi associated with free-living soil nematodes in Turkey

    Directory of Open Access Journals (Sweden)

    Karabörklü Salih

    2015-01-01

    Full Text Available Free-living soil nematodes have successfully adapted world-wide to nearly all soil types from the highest to the lowest of elevations. In the current study, nematodes were isolated from soil samples and fungi associated with these free-living soil nematodes were determined. Large subunit (LSU rDNAs of nematode-associated fungi were amplified and sequenced to construct phylogenetic trees. Nematode-associated fungi were observed in six nematode strains belonging to Acrobeloides, Steinernema and Cephalobus genera in different habitats. Malassezia and Cladosporium fungal strains indicated an association with Acrobeloides and Cephalobus nematodes, while Alternaria strains demonstrated an association with the Steinernema strain. Interactions between fungi and free-living nematodes in soil are discussed. We suggest that nematodes act as vectors for fungi.

  13. A Plant-Feeding Nematode Indirectly Increases the Fitness of an Aphid

    Directory of Open Access Journals (Sweden)

    Grace A. Hoysted

    2017-11-01

    Full Text Available Plants suffer multiple, simultaneous assaults from above and below ground. In the laboratory, pests and/or pathogen attack are commonly studied on an individual basis. The molecular response of the plant to attack from multiple organisms and the interaction of different defense pathways is unclear. The inducible systemic responses of the potato (Solanum tuberosum L. host plant were analyzed to characterize the plant-mediated indirect interactions between a sedentary, endoparasitic nematode (Globodera pallida, and a phloem-sucking herbivore (Myzus persicae. The reproductive success of M. persicae was greater on potato plants pre-infected with G. pallida compared to control plants. Salicylic acid (SA increased systemically in the leaves of potato plants following nematode and aphid infection singly with a corresponding increase in expression of SA-mediated marker genes. An increase in jasmonic acid associated with aphid infection was suppressed when plants were co-infected with nematodes. Our data suggests a positive, asymmetric interaction between a sedentary endoparasitic nematode and a sap-sucking insect. The systemic response of the potato plant following infection with G. pallida indirectly influences the performance of M. persicae. This work reveals additional secondary benefits of controlling individual crop pests.

  14. Epidemiology and effects of gastrointestinal nematode infection on milk productions of dairy ewes

    Directory of Open Access Journals (Sweden)

    Suarez V.H.

    2009-06-01

    Full Text Available 66 Pampinta breed ewes were studied during milking to evaluate the infection and the effect of gastrointestinal nematode on milk production sheep system. Naturally infected ewes on pasture were randomly allocated to two groups: TG, suppressively treated group every four weeks with levamisole and UG, untreated group. Faecal nematode egg counts and larval differentiation were conducted monthly. Successive groups of worm free tracer lambs were grazed with ewes and then slaughtered for worm counts. Test-day milk yield of individual ewes was recorded and ewe machine-milking period length (MPL were estimated. Faecal egg counts and tracer nematode numbers increased towards midsummer and declined sharply toward the end of the study. TG (188.0 ± 60 liters produced more (p < 0.066 milk liters than UG (171.9 ± 52.2 and TG had significantly more extended (p < 0.041 MPL than those of UG. The present study showed that dairy sheep were negatively affected by worms, even when exposed to short periods of high acute nematode (mainly Haemonchus contortus infection.

  15. Characterization of genes coding for small hypervariable peptides in Globodera rostochiensis

    NARCIS (Netherlands)

    Bers, van N.E.M.

    2008-01-01

    Plant parasitic nematodes secrete a cocktail of effector molecules, which are involved
    in several aspects of the interaction with the host, eg. in host defense suppression, in
    migration and in feeding cell formation. In this thesis, we performed the first study on
    10 novel peptide

  16. First Report of Korean Cyst Nematode, Heterodera koreana, Parasitic on Bamboo, Phyllostachys nigra, from Iran.

    Science.gov (United States)

    Maafi, Zahra Tanha; Taheri, Zahra Majd

    2015-09-01

    Bamboo is grown sporadically in the north of Iran and is confined to very limited areas. The history of growing bamboo was to some extent simultaneous with the entrance, commencement, and growth of the tea industry in the north about a century ago. The bamboo was used for making baskets to transfer the harvested tea foliage from farm to the factory and other linked functions. A main area allocated for bamboo growing is located in Lahidjan Agricultural Research Station (LARS) in the north of Iran, where several species of bamboo were cultivated in an area of 5 ha. The species include five species of Phyllostachys (viz., P. aurea, P. bambusoides, P. decora, P. nigra, P. vivax) and one species of Arundinaria gigantean, Pleioblastus fortune, and Semiarundinaria fastuosa; however, only P. aurea and P. nigra have been precisely identified. A survey on plant parasitic nematodes associated with bamboo mainly on P. nigra in LARS revealed second-stage juveniles of cyst forming nematode in soil samples. Further analysis of root and soil samples led to recovery of a cyst nematode belonging to the genus Heterodera and the Afenestrata group. Cysts, vulval cone, and second-stage juveniles were studied for morphological and morphometric features. The classical identification was followed by amplification of the ribosomal RNA-ITS region and the D2-D3 expansion segments of 28S large-subunit rRNA gene; the amplified fragments were sequenced, edited, and compared with those of the corresponding published gene sequences. New D2-D3 and rRNA-ITS gene sequences were deposited in the GenBank database under the accession numbers KR818910 and KR818911, respectively. Based on the morphological and molecular data, the species of the cyst-forming nematode was identified as H. koreana (Vovlas et al., 1992; Mundo-Ocampo et al., 2008). The body contour of cysts was mainly subspherical, vey often with irregular shape (Fig. 1A), yellowish to light brown, thin cuticle with fine zigzag pattern

  17. Extended phenotype: nematodes turn ants into bird-dispersed fruits

    DEFF Research Database (Denmark)

    Hughes, D P; Kronauer, D J C; Boomsma, J J

    2008-01-01

    A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs.......A recent study has discovered a novel extended phenotype of a nematode which alters its ant host to resemble ripe fruit. The infected ants are in turn eaten by frugivorous birds that disperse the nematode's eggs....

  18. Studies on Lasioseius scapulatus, a Mesostigmatid mite predaceous on nematodes

    OpenAIRE

    Imbriani, I.; Mankau, R.

    1983-01-01

    The life history and feeding habits of Lasioseius scapulatus, an ascid predator and potential biocontrol agent of nematodes, was examined. Reproduction was asexual, and the life cycle was 8-10 days at room temperature. Life history consisted of the egg, protonymph, deutonymph, and adult. Both nymphal stages and the adult captured and consumed nematodes. Two fungal genera and eight genera of nematodes were suitable food sources. Second-stage root-knot nematode juveniles were eaten, but eggs an...

  19. Biocontrol: The Potential of Entomophilic Nematodes in Insect Management

    OpenAIRE

    Webster, John M.

    1980-01-01

    A review of the development of entomophilic nematology and a commentary on the potential of entomophilic nematodes in controlling insect pests. The paper considers some of the major contributions to our knowledge of entomophilic nematology; factors involved in insect pest management and how they are applicable to the use of nematodes; nematodes which are most promising as biological control agents; and problems to be solved to facilitate the use of entomophilic nematodes in insect management.

  20. Effects of Php Gene-Associated versus Induced Resistance to Tobacco Cyst Nematode in Flue-Cured Tobacco

    Science.gov (United States)

    Johnson, Charles S.; Eisenback, Jon D.

    2009-01-01

    Effects of the systemic acquired resistance (SAR)-inducing compound acibenzolar-S-methyl (ASM) and the plant-growth promoting rhizobacterial mixture Bacillus subtilis A13 and B. amyloliquefaciens IN937a (GB99+GB122) were assessed on the reproduction of a tobacco cyst nematode (TCN- Globodera tabacum solanacearum) under greenhouse conditions. Two sets of two independent experiments were conducted, each involving soil or root sampling. Soil sample experiments included flue-cured tobacco cultivars with (Php+: NC71 and NC102) and without (Php-: K326 and K346) a gene (Php) suppressing TCN parasitism. Root sample experiments examined TCN root parasitism of NC71 and K326. Cultivars possessing the Php gene (Php+) were compared with Php- cultivars to assess the effects of resistance mediated via Php gene vs. induced resistance to TCN. GB99+GB122 consistently reduced nematode reproductive ratio on both Php+ and Php- cultivars, but similar effects of ASM across Php- cultivars were less consistent. In addition, ASM application resulted in leaf yellowing and reduced root weight. GB99+GB122 consistently reduced nematode development in roots of both Php+ and Php- cultivars, while similar effects of ASM were frequently less consistent. The results of this study indicate that GB99+GB122 consistently reduced TCN reproduction in all flue-cured tobacco cultivars tested, while the effects of ASM were only consistent in Php+ cultivars. Under most circumstances, GB99+GB122 suppressed nematode reproduction more consistently than ASM compared to the untreated control. PMID:22736824

  1. The prevalence of gastrointestinal nematode infection and their ...

    African Journals Online (AJOL)

    GIN infection was associated with 1.4 litres per cow per day less milk and this ... Gastrointestinal nematode (GIN) infections in cattle are of considerable economic importance .... Table 2. Mean faecal egg counts of gastrointestinal nematodes and the 95% confidence ... 3.2 Gastrointestinal nematode species. The pooled ...

  2. Ecology of the Pinewood Nematode in Southern Pine Chip Piles

    Science.gov (United States)

    L. David Dwinell

    1986-01-01

    The optimum temperature range for pinewood nematodes in southern pine chips was 35 to 40° C. Nematode populations declined at temperatures of -20°C. at temperatures above 45°C. and in anaerobic environments. Wood moisture content and presence of bluestain fungus also influenced nematode populations.

  3. Opportunity to use native nematodes for pest control

    Science.gov (United States)

    We have surveyed wild cranberry bogs in WI and found three isolates of native nematodes. We have been testing these nematodes as potential biological control agents in for cranberry insect pests including sparganothis fruitworm and flea beetle. The nematodes seem to be effective at finding and killi...

  4. 77 FR 22185 - Golden Nematode; Removal of Regulated Areas

    Science.gov (United States)

    2012-04-13

    ...-0036] Golden Nematode; Removal of Regulated Areas AGENCY: Animal and Plant Health Inspection Service..., without change, an interim rule that amended the golden nematode regulations by removing the townships of... that the fields in these two townships are free of golden nematode, and we determined that regulation...

  5. 76 FR 60357 - Golden Nematode; Removal of Regulated Areas

    Science.gov (United States)

    2011-09-29

    .... APHIS-2011-0036] Golden Nematode; Removal of Regulated Areas AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Interim rule and request for comments. SUMMARY: We are amending the golden nematode... infested areas. Surveys have shown that the fields in these two townships are free of golden nematode, and...

  6. The miRNAome dynamics during developmental and metabolic reprogramming of tomato root infected with potato cyst nematode.

    Science.gov (United States)

    Koter, Marek D; Święcicka, Magdalena; Matuszkiewicz, Mateusz; Pacak, Andrzej; Derebecka, Natalia; Filipecki, Marcin

    2018-03-01

    Cyst-forming plant-parasitic nematodes are pests threatening many crops. By means of their secretions cyst nematodes induce the developmental and metabolic reprogramming of host cells that lead to the formation of a syncytium, which is the sole food source for growing nematodes. The in depth micro RNA (miRNA) dynamics in the syncytia induced by Globodera rostochiensis in tomato roots was studied. The miRNAomes were obtained from syncytia covering the early and intermediate developmental stages, and were the subject of differential expression analysis. The expression of 1235 miRNAs was monitored. The fold change (log 2 FC) ranged from -7.36 to 8.38, indicating that this transcriptome fraction was very variable. Moreover, we showed that the DE (differentially expressed) miRNAs do not fully overlap between the selected time points, suggesting infection stage specific regulation by miRNA. The correctness of RNA-seq expression profiling was confirmed by qRT-PCR (quantitative Real Time Polymerase Chain Reaction) for seven miRNA species. Down- and up-regulated miRNA species, including their isomiRs, were further used to identify their potential targets. Among them there are a large number of transcription factors linked to different aspects of plant development belonging to gene families, such as APETALA2 (AP2), SQUAMOSA (MADS-box), MYB, GRAS, and AUXIN RESPONSE FACTOR (ARF). The substantial portion of potential target genes belong to the NB-LRR and RLK (RECEPTOR-LIKE KINASE) families, indicating the involvement of miRNA mediated regulation in defense responses. We also collected the evidence for target cleavage in the case of 29 miRNAs using one of three alternative methods: 5' RACE (5' Rapid Amplification of cDNA Ends), a search of tasiRNA within our datasets, and the meta-analysis of tomato degradomes in the GEO (Gene Expression Omnibus) database. Eight target transcripts showed a negative correlation with their respective miRNAs at two or three time points. These

  7. Interocular suppression

    Science.gov (United States)

    Tuna, Ana Rita; Almeida Neves Carrega, Filipa; Nunes, Amélia Fernandes

    2017-08-01

    The objective of this work is to quantify the suppressive imbalance, based on the manipulation of ocular luminance, between a group of subjects with normal binocular vision and a group of subjects with amblyopia. The result reveals that there are statistically significant differences in interocular dominance between two groups, evidencing a greater suppressive imbalance in amblyopic subjects. The technique used, proved to be a simple, easy to apply and economic method, for quantified ocular dominance. It is presented as a technique with the potential to accompany subjects with a marked dominance in one of the eyes that makes fusion difficult.

  8. Remote Sensing of Parasitic Nematodes in Plants

    Science.gov (United States)

    Lawrence, Gary W.; King, Roger; Kelley, Amber T.; Vickery, John

    2007-01-01

    A method and apparatus for remote sensing of parasitic nematodes in plants, now undergoing development, is based on measurement of visible and infrared spectral reflectances of fields where the plants are growing. Initial development efforts have been concentrated on detecting reniform nematodes (Rotylenchulus reniformis) in cotton plants, because of the economic importance of cotton crops. The apparatus includes a hand-held spectroradiometer. The readings taken by the radiometer are processed to extract spectral reflectances at sixteen wavelengths between 451 and 949 nm that, taken together, have been found to be indicative of the presence of Rotylenchulus reniformis. The intensities of the spectral reflectances are used to estimate the population density of the nematodes in an area from which readings were taken.

  9. Nematode taxonomy: from morphology to metabarcoding

    Science.gov (United States)

    Ahmed, M.; Sapp, M.; Prior, T.; Karssen, G.; Back, M.

    2015-11-01

    Nematodes represent a species rich and morphologically diverse group of metazoans inhabiting both aquatic and terrestrial environments. Their role as biological indicators and as key players in nutrient cycling has been well documented. Some groups of nematodes are also known to cause significant losses to crop production. In spite of this, knowledge of their diversity is still limited due to the difficulty in achieving species identification using morphological characters. Molecular methodology has provided very useful means of circumventing the numerous limitations associated with classical morphology based identification. We discuss herein the history and the progress made within the field of nematode systematics, the limitations of classical taxonomy and how the advent of high throughput sequencing is facilitating advanced ecological and molecular studies.

  10. Venereal worms: sexually transmitted nematodes in the decorated cricket.

    Science.gov (United States)

    Luong, L T; Platzer, E G; Zuk, M; Giblin-Davis, R M

    2000-06-01

    The nematode, Mehdinema alii, occurs in the alimentary canal of the decorated cricket Gryllodes sigillatus. Adult nematodes occur primarily in the hindgut of mature male crickets, whereas juvenile nematodes are found in the genital chambers of mature male and female crickets. Here, we present experimental evidence for the venereal transmission of M. alii in G. sigillatus. Infectivity experiments were conducted to test for transmission via oral-fecal contamination, same-sex contact, and copulation. The infective dauers of the nematode are transferred from male to female crickets during copulation. Adult female crickets harboring infective dauers subsequently transfer the nematode to their next mates. Thus, M. alii is transmitted sexually during copulation.

  11. An improved method for generating axenic entomopathogenic nematodes.

    Science.gov (United States)

    Yadav, Shruti; Shokal, Upasana; Forst, Steven; Eleftherianos, Ioannis

    2015-09-19

    Steinernema carpocapsae are parasitic nematodes that invade and kill insects. The nematodes are mutualistically associated with the bacteria Xenorhabdus nematophila and together form an excellent model to study pathogen infection processes and host anti-nematode/antibacterial immune responses. To determine the contribution of S. carpocapsae and their associated X. nematophila to the successful infection of insects as well as to investigate the interaction of each mutualistic partner with the insect immune system, it is important to develop and establish robust methods for generating nematodes devoid of their bacteria. To produce S. carpocapsae nematodes without their associated X. nematophila bacteria, we have modified a previous method, which involves the use of a X. nematophila rpoS mutant strain that fails to colonize the intestine of the worms. We confirmed the absence of bacteria in the nematodes using a molecular diagnostic and two rounds of an axenicity assay involving appropriate antibiotics and nematode surface sterilization. We used axenic and symbiotic S. carpocapsae to infect Drosophila melanogaster larvae and found that both types of nematodes were able to cause insect death at similar rates. Generation of entomopathogenic nematodes lacking their mutualistic bacteria provides an excellent tool to dissect the molecular and genetic basis of nematode parasitism and to identify the insect host immune factors that participate in the immune response against nematode infections.

  12. Cryopreservation of roe deer abomasal nematodes for morphological identification.

    Science.gov (United States)

    Beraldo, Paola; Pascotto, Ernesto

    2014-02-01

    Conventional methods to preserve adult nematodes for taxonomic purposes involve the use of fixative or clearing solutions (alcohol, formaldehyde, AFA and lactophenol), which cause morphological alterations and are toxic. The aim of this study is to propose an alternative method based on glycerol-cryopreservation of nematodes for their subsequent identification. Adults of trichostrongylid nematodes from the abomasum of roe deer (Capreolus capreolus Linnaeus) were glycerol-cryopreserved and compared with those fixed in formaldehyde, fresh and frozen without cryoprotectans. Morphology, transparency and elasticity of the anterior and posterior portion of male nematodes were compared, especially the caudal cuticular bursa and genital accessories. The method presented is quick and easy to use, and the quality of nematode specimens is better than that of nematodes fixed by previously used fixatives. Moreover, glycerol cryopreserved nematodes can be stored for a long time at -20 degrees C in perfect condition and they could be suitable for further analyses, such as histological or ultrastructural examinations.

  13. Induction of SA-signaling pathway and ethylene biosynthesis in Trichoderma harzianum-treated tomato plants after infection of the root-knot nematode Meloidogyne incognita.

    Science.gov (United States)

    Leonetti, Paola; Zonno, Maria Chiara; Molinari, Sergio; Altomare, Claudio

    2017-04-01

    Salicylic acid-signaling pathway and ethylene biosynthesis were induced in tomato treated with Trichoderma harzianum when infected by root-knot nematodes and limited the infection by activation of SAR and ethylene production. Soil pre-treatment with Trichoderma harzianum (Th) strains ITEM 908 (T908) and T908-5 decreased susceptibility of tomato to Meloidogyne incognita, as assessed by restriction in nematode reproduction and development. The effect of T. harzianum treatments on plant defense was detected by monitoring the expression of the genes PR-1/PR-5 and JERF3/ACO, markers of the SA- and JA/ET-dependent signaling pathways, respectively. The compatible nematode-plant interaction in absence of fungi caused a marked suppression of PR-1, PR-5, and ACO gene expressions, either locally or systemically, whilst expression of JERF3 gene resulted unaffected. Conversely, when plants were pre-treated with Th-strains, over-expression of PR-1, PR-5, and ACO genes was observed in roots 5 days after nematode inoculation. JERF3 gene expression did not change in Th-colonized plants challenged with nematodes. In the absence of nematodes, Trichoderma-root interaction was characterized by the inhibition of both SA-dependent signaling pathway and ET biosynthesis, and, in the case of PR-1 and ACO genes, this inhibition was systemic. JERF3 gene expression was systemically restricted only at the very early stages of plant-fungi interaction. Data presented indicate that Th-colonization primed roots for Systemic Acquired Resistance (SAR) against root-knot nematodes and reacted to nematode infection more efficiently than untreated plants. Such a response probably involves also activation of ET production, through an augmented transcription of the ACO gene, which encodes for the enzyme catalyzing the last step of ET biosynthesis. JA signaling and Induced Systemic Resistance (ISR) do not seem to be involved in the biocontrol action of the tested Th-strains against RKNs.

  14. PCR detection of potato cyst nematode.

    Science.gov (United States)

    Reid, Alex

    2009-01-01

    Potato cyst nematode (PCN) is responsible for losses in potato production totalling millions of euros every year in the EC. It is important for growers to know which species is present in their land as this determines its subsequent use. The two species Globodera pallida and Globodera rostochiensis can be differentiated using an allele-specific PCR.

  15. [Biomorphology of gastrointestinal nematodes of small ruminants].

    Science.gov (United States)

    Giannetto, S

    2006-09-01

    Under the term gastrointestinal nematodes are included numerous parasites species of livestock belonging to the families Strongyloididae (Strongyloides), Strongylidae (Chabertia, Oesophagostomum) Trichostrongylidae (Trichostrongylus, Ostertagia, Teladorsagia, Cooperia, Marshallagia), Molineidae (Nematodirus), Ancylostomatidae (Bunostomum) and Trichuridae (Trichuris). This paper reviews the biomorphology aspects of these parasites as well as the controversy by the taxonomists in the classifications.

  16. Excretory/secretory products of anisakid nematodes

    DEFF Research Database (Denmark)

    Mehrdana, Foojan; Buchmann, Kurt

    2017-01-01

    Parasites from the family Anisakidae are widely distributed in marine fish populations worldwide and mainly nematodes of the three genera Anisakis, Pseudoterranova and Contracaecum have attracted attention due to their pathogenicity in humans. Their life cycles include invertebrates and fish as i...

  17. Potato cyst nematodes: pests of national importance

    Science.gov (United States)

    Potato cyst nematodes (PCN; G. rostochiensis and G. pallida) are internationally-recognized quarantine pests and considered the most devastating pests of potatoes due to annual worldwide yield losses estimated at 12.2%. PCNs continue to spread throughout North America and were recently detected in I...

  18. Nutritional requirements for soybean cyst nematode

    Science.gov (United States)

    Soybeans [Glycine max] are the second largest cash crop in US Agriculture, but the soybean yield is compromised by infections from Heterodera glycines, also known as Soybean Cyst Nematodes [SCN]. SCN are the most devastating pathogen or plant disease soybean producers confront. This obligate parasi...

  19. Natural product synthesis: Making nematodes nervous

    Science.gov (United States)

    Snyder, Scott A.

    2011-06-01

    A highly inventive route for the synthesis of a key substance that stimulates potato cyst nematodes to hatch has been developed. This discovery has potential to impact food supplies, as treatment of crops with this compound could alleviate the devastating effect of these parasites.

  20. Nematodes: Model Organisms in High School Biology

    Science.gov (United States)

    Bliss, TJ; Anderson, Margery; Dillman, Adler; Yourick, Debra; Jett, Marti; Adams, Byron J.; Russell, RevaBeth

    2007-01-01

    In a collaborative effort between university researchers and high school science teachers, an inquiry-based laboratory module was designed using two species of insecticidal nematodes to help students apply scientific inquiry and elements of thoughtful experimental design. The learning experience and model are described in this article. (Contains 4…

  1. Nematode survival in relation to soil moisture

    NARCIS (Netherlands)

    Simons, W.R.

    1973-01-01

    Established nematode populations are very persistent in the soil. It is known that they need sufficient soil moisture for movement, feeding and reproduction (fig. 5), and that there are adverse soil moisture conditions which they cannot survive. The influence of soil moisture on survival

  2. Results of the FAO/IAEA program on 'Irradiation as a Quarantine Treatment of Mites, Nematodes and Insects other than Fruit Fly'

    International Nuclear Information System (INIS)

    Ignatowicz, S.

    1998-01-01

    The FAO/IAEA Program on 'Irradiation as a Quarantine Treatment of Mites, Nematodes and Insects other than Fruit Fly' has been implemented in 1992, and lasted up to the end of 1997. The Coordination Research Program put emphasis on the following aspects of research: (1) Determine criteria, e.g. inability to reproduce, for accepting irradiation as a quarantine treatment against quarantine pests; (2) Determine the effete of irradiation on the most resistant stage of these quarantine pests at the time of treatment; (3) Evaluate the quality of agricultural commodities irradiated at 2-3 times the dose(s) required to meet quarantine requirements; (4) Develop method(s) for identifying insects/other pests which were subjected to irradiation at a dose required for quarantine purposes. The followings are the most important achievements of the CRP: Generic dose for sterilization of both males and females of spider mites (Tetranychidae) was determined to be 320 Gy. With regard to insects other than fruit flies, it appears that a minimum dose of 300 Gy would cause either no adult emergence or sterility of most species of insects studied. Radiation doses required to cause complete mortality to various infective stages of plant parasitic nematodes is higher than 6 kGy. The minimum dose required to prevent gall development and reproduction of these nematodes is largely over 2 kGy, which is too high for most fresh plant materials. Thus, irradiation should be considered as an alternative to methyl bromide fumigation to control nematodes in non-perishable materials. While many fresh fruits and vegetables could tolerate radiation doses required for quarantine purposes, the response of various types of cut-flowers to irradiation varied widely. Some cut-flowers and ornamentals such as ferns, phoenix leaf, narcissus, tulips, carnation or red ginger were tolerant to radiation up to 700 Gy and more, others such as chrysanthemum, rose, lily, anthurium, dendrobium, gerbera did not tolerate

  3. Benzimidazole resistance of sheep nematodes in Norway confirmed through controlled efficacy test

    Directory of Open Access Journals (Sweden)

    Domke Atle V

    2012-08-01

    Full Text Available Abstract Background Resistance against benzimidazoles (BZ has recently been detected in Norwegian sheep flocks through a large scale prevalence survey based on the faecal egg count reduction test (FECRT. The use of this test in combination with bulk larval culture only gives an indication of which gastrointestinal nematodes genera that are involved and these results have to be confirmed by a controlled efficacy test (CET to get accurate information about resistant nematodes populations at species level. A CET was therefore performed with larvae from two flocks where BZ resistance was previously detected through FECRT. Results The latter test confirmed the previous results in both flocks. In flock A, the BZ resistant nematode population consisted solely of Haemonchus contortus, whereas H. contortus and Teladorsagia circumcincta comprised the resistant worm population in flock B. Conclusions Some discrepancies that have been recorded between FECRT and CET results regarding time for post-treatment coproscopical examination and a temporary suppression of faecal egg excretion are discussed.

  4. The bacterial community of entomophilic nematodes and host beetles.

    Science.gov (United States)

    Koneru, Sneha L; Salinas, Heilly; Flores, Gilberto E; Hong, Ray L

    2016-05-01

    Insects form the most species-rich lineage of Eukaryotes and each is a potential host for organisms from multiple phyla, including fungi, protozoa, mites, bacteria and nematodes. In particular, beetles are known to be associated with distinct bacterial communities and entomophilic nematodes. While entomopathogenic nematodes require symbiotic bacteria to kill and reproduce inside their insect hosts, the microbial ecology that facilitates other types of nematode-insect associations is largely unknown. To illuminate detailed patterns of the tritrophic beetle-nematode-bacteria relationship, we surveyed the nematode infestation profiles of scarab beetles in the greater Los Angeles area over a five-year period and found distinct nematode infestation patterns for certain beetle hosts. Over a single season, we characterized the bacterial communities of beetles and their associated nematodes using high-throughput sequencing of the 16S rRNA gene. We found significant differences in bacterial community composition among the five prevalent beetle host species, independent of geographical origin. Anaerobes Synergistaceae and sulphate-reducing Desulfovibrionaceae were most abundant in Amblonoxia beetles, while Enterobacteriaceae and Lachnospiraceae were common in Cyclocephala beetles. Unlike entomopathogenic nematodes that carry bacterial symbionts, insect-associated nematodes do not alter the beetles' native bacterial communities, nor do their microbiomes differ according to nematode or beetle host species. The conservation of Diplogastrid nematodes associations with Melolonthinae beetles and sulphate-reducing bacteria suggests a possible link between beetle-bacterial communities and their associated nematodes. Our results establish a starting point towards understanding the dynamic interactions between soil macroinvertebrates and their microbiota in a highly accessible urban environment. © 2016 John Wiley & Sons Ltd.

  5. Influence of Bxpel1 Gene Silencing by dsRNA Interference on the Development and Pathogenicity of the Pine Wood Nematode, Bursaphelenchus xylophilus

    Science.gov (United States)

    Qiu, Xiu-Wen; Wu, Xiao-Qin; Huang, Lin; Ye, Jian-Ren

    2016-01-01

    As the causal agent of pine wilt disease (PWD), the pine wood nematode (PWN), Bursaphelenchus xylophilus, causes huge economic losses by devastating pine forests worldwide. The pectate lyase gene is essential for successful invasion of their host plants by plant-parasitic nematodes. To demonstrate the role of pectate lyase gene in the PWD process, RNA interference (RNAi) is used to analyze the function of the pectate lyase 1 gene in B. xylophilus (Bxpel1). The efficiency of RNAi was detected by real-time PCR. The result demonstrated that the quantity of B. xylophilus propagated with control solution treatment was 62 times greater than that soaking in double-stranded RNA (dsRNA) after B. xylophilus inoculation in Botrytis cinerea for the first generation (F1). The number of B. xylophilus soaking in control solution was doubled compared to that soaking in Bxpel1 dsRNA four days after inoculation in Pinus thunbergii. The quantity of B. xylophilus was reduced significantly (p < 0.001) after treatment with dsRNAi compared with that using a control solution treatment. Bxpel1 dsRNAi reduced the migration speed and reproduction of B. xylophilus in pine trees. The pathogenicity to P. thunbergii seedling of B. xylophilus was weaker after soaking in dsRNA solution compared with that after soaking in the control solution. Our results suggest that Bxpel1 gene is a significant pathogenic factor in the PWD process and this basic information may facilitate a better understanding of the molecular mechanism of PWD. PMID:26797602

  6. Transcriptome-wide selection of a reliable set of reference genes for gene expression studies in potato cyst nematodes (Globodera spp.).

    Science.gov (United States)

    Sabeh, Michael; Duceppe, Marc-Olivier; St-Arnaud, Marc; Mimee, Benjamin

    2018-01-01

    Relative gene expression analyses by qRT-PCR (quantitative reverse transcription PCR) require an internal control to normalize the expression data of genes of interest and eliminate the unwanted variation introduced by sample preparation. A perfect reference gene should have a constant expression level under all the experimental conditions. However, the same few housekeeping genes selected from the literature or successfully used in previous unrelated experiments are often routinely used in new conditions without proper validation of their stability across treatments. The advent of RNA-Seq and the availability of public datasets for numerous organisms are opening the way to finding better reference genes for expression studies. Globodera rostochiensis is a plant-parasitic nematode that is particularly yield-limiting for potato. The aim of our study was to identify a reliable set of reference genes to study G. rostochiensis gene expression. Gene expression levels from an RNA-Seq database were used to identify putative reference genes and were validated with qRT-PCR analysis. Three genes, GR, PMP-3, and aaRS, were found to be very stable within the experimental conditions of this study and are proposed as reference genes for future work.

  7. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes.

    Science.gov (United States)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S; Lozano-Torres, Jose L; Grundler, Florian M W; Siddique, Shahid

    2017-12-16

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in plant-nematode interactions remain unexplored. Here, we characterized the role of a group of cell wall receptor proteins in Arabidopsis, designated as polygalacturonase-inhibiting proteins (PGIPs), during infection with the cyst nematode Heterodera schachtii and the root-knot nematode Meloidogyne incognita. PGIPs are encoded by a family of two genes in Arabidopsis, and are involved in the formation of active OG elicitors. Our results show that PGIP gene expression is strongly induced in response to cyst nematode invasion of roots. Analyses of loss-of-function mutants and overexpression lines revealed that PGIP1 expression attenuates infection of host roots by cyst nematodes, but not root-knot nematodes. The PGIP1-mediated attenuation of cyst nematode infection involves the activation of plant camalexin and indole-glucosinolate pathways. These combined results provide new insights into the molecular mechanisms underlying plant damage perception and response pathways during infection by cyst and root-knot nematodes, and establishes the function of PGIP in plant resistance to cyst nematodes. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  8. The effect of different initial densities of nematode (Meloidogyne javanica) on the build-up of Pasteuria penetrans population.

    Science.gov (United States)

    Darban, Daim Ali; Pathan, Mumtaz Ali; Bhatti, Abdul Ghaffar; Maitelo, Sultan Ahmed

    2005-02-01

    Pasteuria penetrans will build-up faster where there is a high initial nematode density and can suppress root-knot nematode populations in the roots of tomato plants. The effect of different initial densities of nematode (Meloidogyne javanica) (150, 750, 1500, 3000) and P. penetrans infected females (F1, F3) densities (F0=control and AC=absolute control without nematode or P. penetrans inoculum) on the build-up of Pasteuria population was investigated over four crop cycles. Two major points of interest were highlighted. First, that within a confined soil volume, densities of P. penetrans can increase >100 times within 2 or 3 crop cycles. Second, from a relatively small amount of spore inoculum, infection of the host is very high. There were more infected females in the higher P. penetrans doses. The root growth data confirms the greater number of females in the controls particularly at the higher inoculum densities in the third and fourth crops. P. penetrans generally caused the fresh root weights to be higher than those in the control. P. penetrans has shown greater reduction of egg masses per plant at most densities. The effects of different initial densities of M. javanica and P. penetrans on the development of the pest and parasite populations were monitored. And no attempt was made to return the P. penetrans spores to the pots after each crop so the build-up in actual numbers of infected females and spores under natural conditions may be underestimated.

  9. Small RNAs and extracellular vesicles in filarial nematodes: From nematode development to diagnostics.

    Science.gov (United States)

    Quintana, J F; Babayan, S A; Buck, A H

    2017-02-01

    Parasitic nematodes have evolved sophisticated mechanisms to communicate with their hosts in order to survive and successfully establish an infection. The transfer of RNA within extracellular vesicles (EVs) has recently been described as a mechanism that could contribute to this communication in filarial nematodes. It has been shown that these EVs are loaded with several types of RNAs, including microRNAs, leading to the hypothesis that parasites could actively use these molecules to manipulate host gene expression and to the exciting prospect that these pathways could result in new diagnostic and therapeutic strategies. Here, we review the literature on the diverse RNAi pathways that operate in nematodes and more specifically our current knowledge of extracellular RNA (exRNA) and EVs derived from filarial nematodes in vitro and within their hosts. We further detail some of the issues and questions related to the capacity of RNA-mediated communication to function in parasite-host interactions and the ability of exRNA to enable us to distinguish and detect different nematode parasites in their hosts. © 2016 The Authors. Parasite Immunology published by John Wiley & Sons Ltd.

  10. Caenorhabditis elegans: nature and nurture gift to nematode parasitologists.

    Science.gov (United States)

    Salinas, Gustavo; Risi, Gastón

    2017-12-06

    The free-living nematode Caenorhabditis elegans is the simplest animal model organism to work with. Substantial knowledge and tools have accumulated over 50 years of C. elegans research. The use of C. elegans relating to parasitic nematodes from a basic biology standpoint or an applied perspective has increased in recent years. The wealth of information gained on the model organism, the use of the powerful approaches and technologies that have advanced C. elegans research to parasitic nematodes and the enormous success of the omics fields have contributed to bridge the divide between C. elegans and parasite nematode researchers. We review key fields, such as genomics, drug discovery and genetics, where C. elegans and nematode parasite research have convened. We advocate the use of C. elegans as a model to study helminth metabolism, a neglected area ready to advance. How emerging technologies being used in C. elegans can pave the way for parasitic nematode research is discussed.

  11. Efficacy of moxidectin against nematodes in naturally infected sheep.

    Science.gov (United States)

    Coles, G C; Giordano-Fenton, D J; Tritschler, J P

    1994-07-09

    The activity of an oral drench of moxidectin against nematodes in naturally infected sheep known to harbour Nematodirus species was evaluated at doses of 0.2 and 0.4 mg/kg bodyweight. Moxidectin was 100 per cent effective against nematodes in the abomasum and 100 per cent effective against nematodes in the small intestine except for adult Trichostrongylus species, against which its efficacy was 94 per cent. It was 100 per cent effective against nematodes in the large intestine except for Trichuris ovis, against which its efficacy was 83 per cent.

  12. identification of banana varieties with resistance to nematodes in ...

    African Journals Online (AJOL)

    jen

    Institut des Sciences Agronomiques du Rwanda (ISAR), ISAR-Kibungo, Ngoma district, Rwanda ... for sustainable nematode management. Previous studies ..... Technology Development and Transfer project. ... INIBAP, Montpellier, France.

  13. Assaying environmental nickel toxicity using model nematodes.

    Directory of Open Access Journals (Sweden)

    David Rudel

    Full Text Available Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 µg Ni/g dry weight of sediment and 50-800 µg NiCl2/L of water, we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegans and P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  14. Association of nematodes and dogwood cankers.

    Science.gov (United States)

    Self, L H; Bernard, E C

    1994-03-01

    Dogwood canker is a serious production problem of unknown etiology. From May 1985 through April 1989, cankers from 290 flowering dogwood trees in 15 separate nurseries were sampled for nematodes. Seventy-three percent (213) of the cankers contained nematodes. Panagrolaimus rigidus (Schneider) Thorne (115/290) and Aphelenchoides spp. (91/290) were the most frequently collected taxa. Panagrolaimus rigidus was reared on 2% water agar with unidentified bacteria as the food source. Aphelenchoides spp. were reared in antibiotic-amended agar culture with the fungus Glomerella cingulata (Stoneman) Spauld. &Schrenk as a food source. Repeated attempts to culture Aphelenchoides spp. on dogwood callus tissue were unsuccessful. Artificially created stem wounds inoculated with combinations of Aphelenchoides spp. and P. rigidus callused completely in 60 days with no indication of canker development. Very low numbers of nematodes were recovered from inoculated trees, but P. rigidus and one Aphelenchoides sp. were efficient dispersers and occurred in treatments other than those in which they were inoculated.

  15. Assaying environmental nickel toxicity using model nematodes

    Science.gov (United States)

    Rudel, David; Douglas, Chandler; Huffnagle, Ian; Besser, John M.; Ingersoll, Christopher G.

    2013-01-01

    Although nickel exposure results in allergic reactions, respiratory conditions, and cancer in humans and rodents, the ramifications of excess nickel in the environment for animal and human health remain largely undescribed. Nickel and other cationic metals travel through waterways and bind to soils and sediments. To evaluate the potential toxic effects of nickel at environmental contaminant levels (8.9-7,600 µg Ni/g dry weight of sediment and 50-800 µg NiCl2/L of water), we conducted assays using two cosmopolitan nematodes, Caenorhabditis elegans and Pristionchus pacificus. We assayed the effects of both sediment-bound and aqueous nickel upon animal growth, developmental survival, lifespan, and fecundity. Uncontaminated sediments were collected from sites in the Midwestern United States and spiked with a range of nickel concentrations. We found that nickel-spiked sediment substantially impairs both survival from larval to adult stages and adult longevity in a concentration-dependent manner. Further, while aqueous nickel showed no adverse effects on either survivorship or longevity, we observed a significant decrease in fecundity, indicating that aqueous nickel could have a negative impact on nematode physiology. Intriguingly, C. elegansand P. pacificus exhibit similar, but not identical, responses to nickel exposure. Moreover, P. pacificus could be tested successfully in sediments inhospitable to C. elegans. Our results add to a growing body of literature documenting the impact of nickel on animal physiology, and suggest that environmental toxicological studies could gain an advantage by widening their repertoire of nematode species.

  16. Prevalence of intestinal nematodes in alcoholic patients

    Directory of Open Access Journals (Sweden)

    Zago-Gomes Maria P.

    2002-01-01

    Full Text Available We report the results of a retrospective study on the frequency of intestinal nematodes among 198 alcoholic and 440 nonalcoholic patients at the University Hospital Cassiano Antonio Moraes in Vitória, ES, Brazil. The control sample included 194 nonalcoholic patients matched according to age, sex and neighborhood and a random sample of 296 adults admitted at the same hospital. Stool examination by sedimentation method (three samples was performed in all patients. There was a significantly higher frequency of intestinal nematodes in alcoholics than in controls (35.3% and 19.2%, respectively, due to a higher frequency of Strongyloides stercoralis (21.7% and 4.1%, respectively. Disregarding this parasite, the frequency of the other nematodes was similar in both groups. The higher frequency of S. stercoralis infection in alcoholics could be explained by immune modulation and/or by some alteration in corticosteroid metabolism induced by chronic ethanol ingestion. Corticosteroid metabolites would mimic the worm ecdisteroids, that would in turn increase the fecundity of females in duodenum and survival of larvae. Consequently, the higher frequency of Strongyloides larvae in stool of alcoholics does not necessarily reflect an increased frequency of infection rate, but only an increased chance to present a positive stool examination using sedimentation methods.

  17. Evaluation of entomopathogenic nematodes and the supernatants of the in vitro culture medium of their mutualistic bacteria for the control of the root-knot nematodes Meloidogyne incognita and M. arenaria.

    Science.gov (United States)

    Kepenekci, Ilker; Hazir, Selcuk; Lewis, Edwin E

    2016-02-01

    The suppressive effects of various formulations of four entomopathogenic nematode (EPN) species and the supernatants of their mutualistic bacteria on the root-knot nematodes (RKNs) Meloidogyne incognita and M. arenaria in tomato roots were evaluated. The EPNs Steinernema carpocapsae, S. feltiae, S. glaseri and Heterorhabditis bacteriophora were applied as either live infective juveniles (IJs) or infected insect cadavers. Spent medium from culturing the bacterial symbionts Xenorhabdus bovienii and Photorhabdus luminescens kayaii with the cells removed was also applied without their nematode partners. The aqueous suspensions of IJs, infected cadaver applications of EPNs and especially treatments of X. bovienii supernatant suppressed the negative impact of RKNs on tomatoes. Specific responses to treatment were reduced RKN egg masses, increased plant height and increased fresh and dry weights compared with the control where only RKNs were applied. Among the treatments tested, the plant-dipping method of X. bovienii into bacterial culture fluid may be the most practical and effective method for M. incognita and M. arenaria control. © 2015 Society of Chemical Industry.

  18. Effect of Entomopathogenic Nematodes on Mesocriconema xenoplax Populations in Peach and Pecan

    Science.gov (United States)

    Nyczepir, A. P.; Shapiro-Ilan, D. I.; Lewis, E. E.; Handoo, Z. A.

    2004-01-01

    The effect of Steinernema riobrave and Heterorhabditis bacteriophora on population density of Mesocriconema xenoplax in peach was studied in the greenhouse. Twenty-one days after adding 112 M. xenoplax adults and juveniles/1,500 cm³ soil to the soil surface of each pot, 50 infective juveniles/cm² soil surface of either S. riobrave or H. bacteriophora were applied. Another entomopathogenic nematode application of the same density was administered 3 months later. The experiment was repeated once. Mesocriconema xenoplax populations were not suppressed (P ≤ 0.05) in the presence of either S. riobrave or H. bacteriophora 180 days following ring nematode inoculation. On pecan, 200 S. riobrave infective-stage juveniles/cm² were applied to the soil surface of 2-year-old established M. xenoplax populations in field microplots. Additional applications of S. riobrave were administered 2 and 4 months later. This study was terminated 150 days following the initial application of S. riobrave. Populations of M. xenoplax were not suppressed in the presence of S. riobrave. PMID:19262805

  19. Effect of Entomopathogenic Nematodes on Mesocriconema xenoplax Populations in Peach and Pecan.

    Science.gov (United States)

    Nyczepir, A P; Shapiro-Ilan, D I; Lewis, E E; Handoo, Z A

    2004-06-01

    The effect of Steinernema riobrave and Heterorhabditis bacteriophora on population density of Mesocriconema xenoplax in peach was studied in the greenhouse. Twenty-one days after adding 112 M. xenoplax adults and juveniles/1,500 cm(3) soil to the soil surface of each pot, 50 infective juveniles/cm(2) soil surface of either S. riobrave or H. bacteriophora were applied. Another entomopathogenic nematode application of the same density was administered 3 months later. The experiment was repeated once. Mesocriconema xenoplax populations were not suppressed (P nematode inoculation. On pecan, 200 S. riobrave infective-stage juveniles/cm(2) were applied to the soil surface of 2-year-old established M. xenoplax populations in field microplots. Additional applications of S. riobrave were administered 2 and 4 months later. This study was terminated 150 days following the initial application of S. riobrave. Populations of M. xenoplax were not suppressed in the presence of S. riobrave.

  20. Meloidogyne incognita Fatty Acid- and Retinol- Binding Protein (Mi-FAR-1) Affects Nematode Infection of Plant Roots and the Attachment of Pasteuria penetrans Endospores.

    Science.gov (United States)

    Phani, Victor; Shivakumara, Tagginahalli N; Davies, Keith G; Rao, Uma

    2017-01-01

    Root-knot nematode (RKN) Meloidogyne incognita is an economically important pest of crops. Pasteuria penetrans , is a nematode hyperparasitic bacterium capable of suppressing the reproduction of RKN and thereby useful for its management. Secreted fatty acid and retinol-binding proteins are unique in nematodes and are engaged in nutrient acquisition, development and reproduction; they are also a component of the nematode cuticle and thought to be involved in the interface between hosts and parasites. Attachment of endospores to the cuticle of second stage juveniles of RKN is the primary step of infection and several factors have been identified to facilitate attachment. In this study, the full length of Mi-far-1 (573 bp) was cloned from M. incognita and characterized. Analysis revealed that the Mi-far-1 was rich in α-helix structure, contained a predicted consensus casein kinase II phosphorylation site and a glycosylation site. Quantitative PCR showed the highest expression in the fourth stage juveniles and in situ hybridization revealed the presence of Mi-far-1 mRNA in the hypodermis below the cuticle. Single copy insertion pattern of Mi-far-1 in M. incognita genome was detected by Southern blotting. Knockdown of Mi-far-1 showed significantly increased attachment of P. penetrans' endospores on juvenile cuticle surface and also affected host finding, root infection and nematode fecundity.

  1. Meloidogyne incognita Fatty Acid- and Retinol- Binding Protein (Mi-FAR-1 Affects Nematode Infection of Plant Roots and the Attachment of Pasteuria penetrans Endospores

    Directory of Open Access Journals (Sweden)

    Victor Phani

    2017-11-01

    Full Text Available Root-knot nematode (RKN Meloidogyne incognita is an economically important pest of crops. Pasteuria penetrans, is a nematode hyperparasitic bacterium capable of suppressing the reproduction of RKN and thereby useful for its management. Secreted fatty acid and retinol-binding proteins are unique in nematodes and are engaged in nutrient acquisition, development and reproduction; they are also a component of the nematode cuticle and thought to be involved in the interface between hosts and parasites. Attachment of endospores to the cuticle of second stage juveniles of RKN is the primary step of infection and several factors have been identified to facilitate attachment. In this study, the full length of Mi-far-1 (573 bp was cloned from M. incognita and characterized. Analysis revealed that the Mi-far-1 was rich in α-helix structure, contained a predicted consensus casein kinase II phosphorylation site and a glycosylation site. Quantitative PCR showed the highest expression in the fourth stage juveniles and in situ hybridization revealed the presence of Mi-far-1 mRNA in the hypodermis below the cuticle. Single copy insertion pattern of Mi-far-1 in M. incognita genome was detected by Southern blotting. Knockdown of Mi-far-1 showed significantly increased attachment of P. penetrans’ endospores on juvenile cuticle surface and also affected host finding, root infection and nematode fecundity.

  2. Unexpected variation in neuroanatomy among diverse nematode species

    Directory of Open Access Journals (Sweden)

    Ziduan eHan

    2016-01-01

    Full Text Available Nematodes are considered excellent models for understanding fundamental aspects of neuron function. However, nematodes are less frequently used as models for examining the evolution of nervous systems. While the habitats and behaviors of nematodes are diverse, the neuroanatomy of nematodes is often considered highly conserved. A small number of nematode species greatly influences our understanding of nematode neurobiology. The free-living species Caenorhabditis elegans and, to a lesser extent, the mammalian gastrointestinal parasite Ascaris suum are, historically, the primary sources of knowledge regarding nematode neurobiology. Despite differences in size and habitat, C. elegans and Ascaris suum share a surprisingly similar neuroanatomy. Here, we examined species across several clades in the phylum Nematoda and show that there is a surprising degree of neuroanatomical variation both within and among nematode clades when compared to C. elegans and Ascaris. We found variation in the numbers of neurons in the ventral nerve cord and dye-filling pattern of sensory neurons. For example, we found that Pristionchus pacificus, a bacterial feeding species used for comparative developmental research, had 20% fewer ventral cord neurons compared to C. elegans. Steinernema carpocapse, an insect-parasitic nematode capable of jumping behavior, had 40% more ventral cord neurons than C. elegans. Interestingly, the non-jumping congeneric nematode, S. glaseri showed an identical number of ventral cord neurons as S. carpocapsae. There was also variability in the timing of neurodevelopment of the ventral cord with two of five species that hatch as second-stage juveniles showing delayed neurodevelopment. We also found unexpected variation in the dye-filling of sensory neurons among examined species. Again, sensory neuron dye-filling pattern did not strictly correlate with phylogeny. Our results demonstrate that variation in nematode neuroanatomy is more prevalent

  3. Trait-mediated diversification in nematode predator–prey systems

    NARCIS (Netherlands)

    Mulder, C.; Helder, J.; Vervoort, M.T.W.; Vonk, J.A.

    2011-01-01

    Nematodes are presumably the most numerous Metazoans in terrestrial habitats. They are represented at all trophic levels and are known to respond to nutrient limitation, prey availability, and microbial resources. Predatory nematodes reside at the highest trophic level, and as such their feeding

  4. A model of nematode dynamics in the Westerschelde estuary

    NARCIS (Netherlands)

    Li, J.; Vincx, M.; Herman, P.M.J.

    1996-01-01

    We developed a time dynamic model to investigate the temporal dynamics of nematode community in the brackish zone of the Westerschelde Estuary. The biomass of four nematode feeding groups observed from March 1991 to February 1992 is used to calibrate the model. Using environmental data as the input,

  5. A Survey of Nematode Infection in Oreochromis niloticus (L ...

    African Journals Online (AJOL)

    The incidence and intensity of nematode infection was investigated in Nile tilapia Oreochromis niloticus from Lake Kyoga, Uganda and 11% of the 406 fish examined were parasitized by nematodes of the genus Contracaecum. The prevalence of these parasites was greatest in the smallest and largest size classes, but this ...

  6. Free-living Marine Nematodes. Part 1 British Enoplids

    African Journals Online (AJOL)

    This is the first of three volumes dealing with the most abundant group of animals on the sea-bed and sea-shore, the free-living marine nematodes, and is devoted to those marine nematodes belonging to the subclass Enoplia. Separate volumes will deal with the orders Chromadorida and. Monhysterida. To most marine ...

  7. 5 Spatial Distribution of Nematodes at Organic.cdr

    African Journals Online (AJOL)

    user

    in organic crop production fields can favour or inhibit nematode build-up. ... that nematode control strategies employed on the organic field might be less effective than expected. ... Method. Study site. Soil samples were collected from an organic vegetable field and a conventional ..... chemical analysis: a practical handbook.

  8. Nematode effector proteins: an emerging paradigm of parasitism

    Science.gov (United States)

    Phytonematodes use a stylet and secreted effectors to invade host tissues and extract nutrients to support their growth and development. The molecular function of nematode effectors is currently the subject of intense investigation. In this review, we summarize our current understanding of nematode ...

  9. Mapping genetic factors controlling potato - cyst nematode interactions

    NARCIS (Netherlands)

    Rouppe van der Voort, J.N.A.M.

    1998-01-01

    The thesis describes strategies for genetic mapping of the genomes of the potato cyst nematode and potato. Mapping in cyst nematodes was achieved by AFLP genotyping of single cysts and subsequent segregation analysis in a family of sibling populations. The genetic map of Globodera

  10. Cyst nematode-induced changes in plant development

    NARCIS (Netherlands)

    Goverse, A.

    1999-01-01

    This thesis describes a first attempt to investigate the biological activity of cyst nematode secretions on plant cell proliferation and the molecular mechanisms underlying feeding cell development in plant roots upon cyst nematode infection.

    To investigate the role of

  11. Molecular and genetic analyses of potato cyst nematode resistance loci

    NARCIS (Netherlands)

    Bakker, E.H.

    2003-01-01

    This thesis describes the genomic localisation and organisation of loci that harbour resistance to the potato cyst nematode species Globodera pallida and G. rostochiensis . Resistance to the potato cyst nematodes G. pallida and G. rostochiensis is an important aspect in potato breeding. To gain

  12. Nematode community structure as a bioindicator in environmental monitoring

    NARCIS (Netherlands)

    Bongers, T.; Ferris, H.

    1999-01-01

    Four of every five multicellular animals on the planet are nematodes. They occupy any niche that provides an available source of organic carbon in marine, freshwater and terrestrial environments. Nematodes vary in sensitivity to pollutants and environmental disturbance. Recent development of indices

  13. Human Intraocular Filariasis Caused by Pelecitus sp. Nematode, Brazil

    Science.gov (United States)

    Bain, Odile; Diniz, Daniel G.; Nascimento dos Santos, Jeannie; Pinto de Oliveira, Norimar; Frota de Almeida, Izabela Negrão; Frota de Almeida, Rafael Negrão; Frota de Almeida, Luciana Negrão; Dantas-Torres, Filipe; Sobrinho, Edmundo Frota de Almeida

    2011-01-01

    A male nematode was extracted from iris fibers of a man from the Brazilian Amazon region. This nematode belonged to the genus Pelecitus but was distinct from the 16 known species in this genus. Similarities with Pelecitus spp. from neotropical birds suggested an avian origin for this species. PMID:21529397

  14. 75 FR 11111 - Pale Cyst Nematode; Update of Quarantined Areas

    Science.gov (United States)

    2010-03-10

    ...] Pale Cyst Nematode; Update of Quarantined Areas AGENCY: Animal and Plant Health Inspection Service...: Background The pale cyst nematode (PCN, Globodera pallida) is a major pest of potato crops in cool... made changes to the area in the State of Idaho that is quarantined to prevent the spread of pale cyst...

  15. 75 FR 54592 - Pale Cyst Nematode; Update of Quarantined Areas

    Science.gov (United States)

    2010-09-08

    ...] Pale Cyst Nematode; Update of Quarantined Areas AGENCY: Animal and Plant Health Inspection Service... made changes to the area in the State of Idaho that is quarantined to prevent the spread of pale cyst nematode. The description of the quarantined area was updated on April 26, 2010. As a result of these...

  16. Biocontrol of ticks by entomopathogenic nematodes. Research update.

    Science.gov (United States)

    Samish, M; Alekseev, E; Glazer, I

    2000-01-01

    Entomopathogenic nematodes (EPNs) are lethal to ticks even though they do not use their normal propagation cycle within tick cadavers. The tick Boophilus annulatus was found to be far more susceptible to EPNs than Hyalomma excavatum, Rhipicephalus bursa, or Rhipicephalus sanguineus. Ticks seem to be less susceptible to nematodes when feeding on a host. Preimaginal tick stages were less susceptible to nematodes than adult ticks. The mortality rate of unfed females was highest, followed by unfed males, and engorged females. The virulence of nematodes to ticks varied greatly among different nematode strains. In most cases, the Heterorhabditis sp. strains were the most virulent strains tested in petri dishes. In buckets containing sandy soil sprayed with 50 nematodes/cm2 and engorged B. annulatus females, the LT50 of the ticks was less than five days. The addition of manure to soil or a manure extract to petri dishes reduced nematode virulence. Since ticks spend most of their life cycle in the upper humid layer of the ground, and many nematode strains share this same ecological niche, the use of EPNs for biocontrol of ticks appears promising.

  17. Laboratory experiments on the infaunal activity of intertidal nematodes

    NARCIS (Netherlands)

    Steyaert, M.; Moodley, L.; Vanaverbeke, J.; Vandewiele, S.L.; Vincx, M.

    2005-01-01

    The impact of oxygen on the vertical distribution of an intertidal nematode community was investigated in a manipulation experiment with sediments collected from the Oosterschelde (The Netherlands). The vertical distribution of nematodes was examined in response to sediment inversion in perspex

  18. Native nematodes as new bio-insecticides for cranberries

    Science.gov (United States)

    In the summer of 2015, an effort was made in central Wisconsin to find an entomopathogenic nematode capable controlling Wisconsin’s cranberry pests. Using a standard baiting method, a nematode of the Oscheius genus was collected from the mossy, sandy, peat-filled soils of a wild cranberry marsh. Thi...

  19. The cyst nematodes Heterodera and Globodera species in Egypt

    Science.gov (United States)

    Information concerning the occurrence and distribution of the cyst nematodes (Heterodera spp. and Globodera spp.) in Egypt is important to assess their potential to cause economic damage to many crop plants. A nematode survey was conducted in Alexandria, El Behera and Sohag governorates during 2012-...

  20. Screening of in vitro derived mutants of banana against nematodes ...

    African Journals Online (AJOL)

    The rest of the mutants namely Ro Im V4 6-1-2 and Si Im V4 6-2-5 were found to be susceptible to nematodes. The resistant and moderately resistant mutants of banana could be further used in breeding programmes as well as being recognized as potential cultivars of commerce. Key words: Banana, nematode, resistance, ...

  1. Statistical analysis of nematode counts from interlaboratory proficiency tests

    NARCIS (Netherlands)

    Berg, van den W.; Hartsema, O.; Nijs, Den J.M.F.

    2014-01-01

    A series of proficiency tests on potato cyst nematode (PCN; n=29) and free-living stages of Meloidogyne and Pratylenchus (n=23) were investigated to determine the accuracy and precision of the nematode counts and to gain insights into possible trends and potential improvements. In each test, each

  2. Nematode parasitism in adult dairy cows in Belgium

    NARCIS (Netherlands)

    Agneessens, J.; Claerebout, E.; Dorny, P.; Borgsteede, F.H.M.; Vercruysse, J.

    2000-01-01

    Over a period of 1 year, from November 1997 to October 1998, the abomasa, blood and faecal samples of 121 dairy cows in Belgium were collected and examined for nematode infections. Nematodes were present in the abomasa of 110 animals. Ostertagia was found in all 110, Trichostrongylus was seen in 65

  3. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Directory of Open Access Journals (Sweden)

    Mohamed Adam

    Full Text Available The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  4. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Science.gov (United States)

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  5. Entomogenous nematode Neoaplectana carpocapsae: radiation and mammalian safety

    International Nuclear Information System (INIS)

    Gaugler, R.R.

    1978-01-01

    Infective-stage juveniles of Neoaplacetana carpocapsae were acutely sensitive to short uv radiation (254 nm) and natural sunlight. High nematode mortality, although delayed, accompanied uv exposure. Irradiation rapidly reduced nematode pathogenicity, so that nematodes exposed for 7 min were unable to cause lethal infections in Galleria mallonella larvae. Moreover, the median survival time of Galleria larvae increased progressively as nematode exposure to uv was lengthened. Inhibition of nematode reproduction and development was noted at exposure periods more than 2.45 and 5 min, respectively. However, irradiation did not appear to affect juvenile motility. Exposure to direct sunlight also reduced pathogenicity, in a range from 6.9 to 94.9% at 30 and 60 min of exposure, respectively. Long uv (366 nm) did not affect juveniles at the exposures tested

  6. BASIDIOMYCETE-BASED METHOD FOR BIOCONTROL OF PHYTOPATHOGENIC NEMATODES

    Directory of Open Access Journals (Sweden)

    Tiberius BALAEŞ

    2015-12-01

    Full Text Available Phytopathogenic nematodes represent one of the most important groups of pathogens in crops. The use of chemical to control the nematodes attack in crops is decreasing every year due to the concern of the toxicity and side effects of such compounds. In the course for finding alternatives to the use of chemicals, biological control of nematodes is gaining much attention. Some saprotrophic fungi are able to feed on invertebrates, thus becoming efficient agents of control. In this study, three species of basidiomycetes were analyzed for their potential to be used as control agents of phytopathogenic nematodes. Through on in vitro investigation of these potential, one strain – Gymnopilus junonius was further selected for a pot test against Meloidogyne incognita, a very important phytopathogenic species of nematodes. The fungal treatment strongly decreased the M. incognita population on the tested pots, proving the potential of G. junonius strain to be used in biocontrol.

  7. Survey of nematodes associated with terrestrial slugs in Norway.

    Science.gov (United States)

    Ross, J L; Ivanova, E S; Hatteland, B A; Brurberg, M B; Haukeland, S

    2016-09-01

    A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway.

  8. Coupling of MIC-3 overexpression with the chromosome 11 and 14 root-knot nematode (RKN) (Meloidogyne incognita) resistance QTLs provides insights into the regulation of the RKN resistance response in Upland cotton...

    Science.gov (United States)

    High levels of resistance to root-knot nematode (RKN) (Meloidogyne incognita) in Upland cotton (Gossypium hirsutum) is mediated by two major quantitative trait loci (QTL) located on chromosomes 11 and 14. We had previously determined that MIC-3 expression played a direct role in suppressing RKN egg...

  9. Multifaceted effects of host plants on entomopathogenic nematodes.

    Science.gov (United States)

    Hazir, Selcuk; Shapiro-Ilan, David I; Hazir, Canan; Leite, Luis G; Cakmak, Ibrahim; Olson, Dawn

    2016-03-01

    The success of parasites can be impacted by multi-trophic interactions. Tritrophic interactions have been observed in parasite-herbivore-host plant systems. Here we investigate aspects of multi-trophic interactions in a system involving an entomopathogenic nematode (EPN), its insect host, and host plant. Novel issues investigated include the impact of tritrophic interactions on nematode foraging behavior, the ability of EPNs to overcome negative tritrophic effects through genetic selection, and interactions with a fourth trophic level (nematode predators). We tested infectivity of the nematode, Steinernema riobrave, to corn earworm larvae (Helicoverpa zea) in three host plants, tobacco, eggplant and tomato. Tobacco reduced nematode virulence and reproduction relative to tomato and eggplant. However, successive selection (5 passages) overcame the deficiency; selected nematodes no longer exhibited reductions in phenotypic traits. Despite the loss in virulence and reproduction nematodes, first passage S. riobrave was more attracted to frass from insects fed tobacco than insects fed on other host plants. Therefore, we hypothesized the reduced virulence and reproduction in S. riobrave infecting tobacco fed insects would be based on a self-medicating tradeoff, such as deterring predation. We tested this hypothesis by assessing predatory success of the mite Sancassania polyphyllae and the springtail Sinella curviseta on nematodes reared on tobacco-fed larvae versus those fed on greater wax moth, Galleria mellonella, tomato fed larvae, or eggplant fed larvae. No advantage was observed in nematodes derived from tobacco fed larvae. In conclusion, our results indicated that insect-host plant diet has an important effect on nematode foraging, infectivity and reproduction. However, negative host plant effects, might be overcome through directed selection. We propose that host plant species should be considered when designing biocontrol programs using EPNs. Copyright © 2016

  10. Development of the system nematode, Ditylenchus Dipsaci (Kuehn) Filipjev, and the potato tuber nematode, D. Destructor thore, after gamma irradiation

    International Nuclear Information System (INIS)

    Ignatowicz, S.; Karnkowski, W.

    1996-01-01

    Juvenile and adult nematodes emerged from onion and garlic samples on the 3 rd week after irradiation with doses up to 0.5 kGy and from potato treated with doses up to 2.0 kGy. However, irradiation of onion infected with Ditylenchus dipsaci caused the inhibition of the development and growth of juvenile nematodes to mature forms. Doses of gamma radiation ranging from 0.1 to 0.5 kGy had only a slight effect, if any, on the development and growth of D. dipsaci nematodes infecting garlic, but they increased juvenile mortality. Gamma radiation at doses up to 2.0 kGy induced increased mortality of nematode juveniles of the potato tuber nematode, D. destructor but less so inhibited their development to mature forms. Nematodes were found to be resistant to irradiation treatment. Therefore the use of gamma irradiation for nematode disinfestation of agricultural products seems to be impractical, if the aim of the treatment is to kill these pests within a few weeks. The level of radiation required to kill nematodes in infected plants would damage plant tissues so that the further storage of vegetables will be impossible. (author). 22 refs, 3 figs, 2 tabs

  11. Entomopathogenic nematodes in the European biocontrol market.

    Science.gov (United States)

    Ehlers, R U

    2003-01-01

    In Europe total revenues in the biocontrol market have reached approximately 200 million Euros. The sector with the highest turn-over is the market for beneficial invertebrates with a 55% share, followed by microbial agents with approximately 25%. Annual growth rates of up to 20% have been estimated. Besides microbial plant protection products that are currently in the process of re-registration, several microbial products have been registered or are in the process of registration, following the EU directive 91/414. Entomopathogenic nematodes (EPN) are exceptionally safe biocontrol agents. Until today, they are exempted from registration in most European countries, the reason why SMEs were able to offer economically reasonable nematode-based products. The development of technology for mass production in liquid media significantly reduced the product costs and accelerated the introduction of nematode products in tree nurseries, ornamentals, strawberries, mushrooms, citrus and turf. Progress in storage and formulation technology has resulted in high quality products which are more resistant to environmental extremes occurring during transportation to the user. The cooperation between science, industry and extension within the EU COST Action 819 has supported the development of quality control methods. Today four companies produce EPN in liquid culture, offering 8 different nematode species. Problems with soil insects are increasing. Grubs, like Melolontha melolontha and other scarabaeidae cause damage in orchards and turf. Since the introduction of the Western Corn Rootworm Diabrotica virgifera into Serbia in 1992, this pests as spread all over the Balkan Region and has reached Italy, France and Austria. These soil insect pests are potential targets for EPN. The development of insecticide resistance has opened another sector for EPN. Novel adjuvants used to improve formulation of EPN have enabled the foliar application against Western Flower Thrips and Plutella

  12. Persistence and Suppressiveness of Pasteuria penetrans to Meloidogyne arenaria Race.

    Science.gov (United States)

    Cetintas, R; Dickson, D W

    2004-12-01

    The long-term persistence and suppressiveness of Pasteuria penetrans against Meloidogyne arenaria race 1 were investigated in a formerly root-knot nematode suppressive site following 9 years of continuous cultivation of three treatments and 4 years of continuous peanut. The three treatments were two M. arenaria race 1 nonhost crops, bahiagrass (Paspalum notatum cv. Pensacola var. Tifton 9), rhizomal peanut (Arachis glabrata cv. Florigraze), and weed fallow. Two root-knot nematode susceptible weeds commonly observed in weed fallow plots were hairy indigo (Indigofera hirsuta) and alyce clover (Alysicarpus vaginalis). The percentage of J2 with endospores attached reached the highest level of 87% in 2000 in weed fallow, and 63% and 53% in 2002 in bahiagrass and rhizomal peanut, respectively. The percentage of endospore-filled females extracted from peanut roots grown in weed fallow plots increased from nondetectable in 1999 to 56% in 2002, whereas the percentages in bahiagrass and rhizomal peanut plots were 41% and 16%, respectively. Over 4 years, however, there was no strong evidence that endospores densities reached suppressive levels because peanut roots, pods, and pegs were heavily galled, and yields were suppressed. This might be attributed to the discovery of M. javanica infecting peanut in this field in early autumn 2001. A laboratory test confirmed that although the P. penetrans isolate specific to M. arenaria attached to M. javanica J2, no development occurred. In summary, P. penetrans increased on M. arenaria over a 4-year period, but apparently because of infection of M. javanica on peanut at the field site root-knot disease was not suppressed. This was confirmed by a suppressive soil test that showed a higher level of soil suppressiveness than occurred in the field (P

  13. Mining the secretome of root-knot nematodes for cell wall modifying proteins

    NARCIS (Netherlands)

    Roze, E.H.A.

    2008-01-01

    The products of parasitism genes in nematodes must be secreted to reach their targets at the nematode-plant interface. These nematode secretory proteins are therefore recognised to play an important role in the nematode-plant interaction and as a result have been subject of intense study for years.

  14. [Nematodes (Nematoda) from bats (Chiroptera) of the Samarskaya Luka Peninsula (Russia)].

    Science.gov (United States)

    Kirillova, N Iu; Kirillov, A A; Vekhnik, V P

    2008-01-01

    Fauna of parasitic nematodes from Chiroptera of the Samarskaya Luka has been studied. Seven nematode species has been recorded. Numbers of host specimens, indices of extensiveness and intensiveness of the invasion, parasite abundance, and brief characteristics of the nematode species are given. Some nematode species were for the first time recorded in bats of Russia.

  15. Viability Test Device for anisakid nematodes

    Directory of Open Access Journals (Sweden)

    Michael Kroeger

    2018-03-01

    Full Text Available Up to now the visual inspection of mobility of isolated anisakid larvae serves as a measure of viability and possible risk of infection. This paper presents a new method to rule out unreliability – caused by the temporary immobility of the larvae and by the human uncertainty factor of visual observation. By means of a Near infrared (NIR imaging method, elastic curvature energies and geometric shape parameters were determined from contours, and used as a measure of viability. It was based on the modelling of larvae as a cylindrical membrane system. The interaction between curvatures, contraction of the longitudinal muscles, and inner pressure enabled the derivation of viability from stationary form data. From series of spectrally signed images within a narrow wavelength range, curvature data of the larvae were determined. Possible mobility of larvae was taken into account in statistical error variables. Experiments on individual living larvae, long-term observations of Anisakis larvae, and comparative studies of the staining method and the VTD measurements of larvae from the tissue of products confirmed the effectiveness of this method. The VTD differentiated clearly between live and dead nematode larvae isolated from marinated, deep-frozen and salted products. The VTD has been proven as excellent method to detect living anisakid nematode larvae in fishery products and is seen as useful tool for fish processing industry and control authorities. Keywords: Biophysics

  16. Arrested larval development in cattle nematodes.

    Science.gov (United States)

    Armour, J; Duncan, M

    1987-06-01

    Most economically important cattle nematodes are able to arrest their larval development within the host - entering a period of dormancy or hypobiosis. Arrested larvae have a low death rate, and large numbers can accumulate in infected cattle during the grazing season. Because of this, outbreaks of disease caused by such nematodes can occur at times when recent infection with the parasites could not have occurred, for example during winter in temperature northern climates when cattle are normally housed. The capacity to arrest is a heritable trait. It is seen as an adaptation by the parasite to avoid further development to its free-living stages during times when the climate is unsuitable for free-living survival. But levels of arrestment can vary markedly in different regions, in different cattle, and under different management regimes. Climatic factors, previous conditioning, host immune status, and farm management all seem to affect arrestment levels. In this article, James Armour and Mary Duncan review the biological basis of the phenomenon, and discuss the apparently conflicting views on how it is controlled.

  17. The whipworm (Trichuris suis) secretes prostaglandin E2 to suppress proinflammatory properties in human dendritic cells

    DEFF Research Database (Denmark)

    Laan, Lisa C; Williams, Andrew R; Stavenhagen, Kathrin

    2017-01-01

    Clinical trials have shown that administration of the nematode Trichuris suis can be beneficial in treating various immune disorders. To provide insight into the mechanisms by which this worm suppresses inflammatory responses, an active component was purified from T. suis soluble products (TsSPs)...

  18. Identification of Virulence Factors in Nematode-Trapping Fungi - Insights from Genomics, Transcriptomics and Proteomics

    OpenAIRE

    Andersson, Karl-Magnus

    2013-01-01

    Nematode-trapping fungi are soil-living organisms with the unique ability to capture and infect free-living nematodes. The interest in studying these fungi arises from their potential use as biological control agents for plant- and animal-parasitic nematodes. To enter the parasitic stage, nematode-trapping fungi develop different kinds of trapping structures. In order to understand more about the evolution of parasitism in the nematode-trapping fungi and to identify virulence factors in these...

  19. Changes in soil nematode communities under the impact of fertilizers

    Science.gov (United States)

    Gruzdeva, L. I.; Matveeva, E. M.; Kovalenko, T. E.

    2007-06-01

    Changes taking place in the communities of soil nematodes of an artificially sown meadow under the impact of annually applied mineral fertilizers have been studied in a field experiment for nine years. It is shown that changes in the species composition, trophic structure, and numbers of nematodes from different genera depend on the fertilizer applied and on the competitiveness of the plant species grown. The spectra of nematode genera sensitive to the complete mineral fertilizer (NPK) and to the particular nutrients have been identified with the use of a number of parameters, including the maturity index of nematode communities, the biotope preferences of the particular nematode genera, and the general pattern of nematode habitats. The results obtained in this study can be used to assess the effect of mineral fertilizers on the soil fauna and to suggest optimum application rates of mineral fertilizers ensuring the sustainable development of meadow herbs. The use of the data on the trophic structure of nematode communities for predicting the ways of organic matter decomposition in the soil is discussed.

  20. Reciprocal Interactions between Nematodes and Their Microbial Environments.

    Science.gov (United States)

    Midha, Ankur; Schlosser, Josephine; Hartmann, Susanne

    2017-01-01

    Parasitic nematode infections are widespread in nature, affecting humans as well as wild, companion, and livestock animals. Most parasitic nematodes inhabit the intestines of their hosts living in close contact with the intestinal microbiota. Many species also have tissue migratory life stages in the absence of severe systemic inflammation of the host. Despite the close coexistence of helminths with numerous microbes, little is known concerning these interactions. While the environmental niche is considerably different, the free-living nematode Caenorhabditis elegans ( C. elegans ) is also found amongst a diverse microbiota, albeit on decaying organic matter. As a very well characterized model organism that has been intensively studied for several decades, C. elegans interactions with bacteria are much more deeply understood than those of their parasitic counterparts. The enormous breadth of understanding achieved by the C. elegans research community continues to inform many aspects of nematode parasitology. Here, we summarize what is known regarding parasitic nematode-bacterial interactions while comparing and contrasting this with information from work in C. elegans . This review highlights findings concerning responses to bacterial stimuli, antimicrobial peptides, and the reciprocal influences between nematodes and their environmental bacteria. Furthermore, the microbiota of nematodes as well as alterations in the intestinal microbiota of mammalian hosts by helminth infections are discussed.

  1. Unraveling flp-11/flp-32 dichotomy in nematodes.

    Science.gov (United States)

    Atkinson, Louise E; Miskelly, Iain R; Moffett, Christy L; McCoy, Ciaran J; Maule, Aaron G; Marks, Nikki J; Mousley, Angela

    2016-10-01

    FMRFamide-like peptide (FLP) signalling systems are core to nematode neuromuscular function. Novel drug discovery efforts associated with nematode FLP/FLP receptor biology are advanced through the accumulation of basic biological data that can reveal subtle complexities within the neuropeptidergic system. This study reports the characterisation of FMRFamide-like peptide encoding gene-11 (flp-11) and FMRFamide-like peptide encoding gene-32 (flp-32), two distinct flp genes which encode the analogous peptide, AMRN(A/S)LVRFamide, in multiple nematode species - the only known example of this phenomenon within the FLPergic system of nematodes. Using bioinformatics, in situ hybridisation, immunocytochemistry and behavioural assays we show that: (i) flp-11 and -32 are distinct flp genes expressed individually or in tandem across multiple nematode species, where they encode a highly similar peptide; (ii) flp-11 does not appear to be the most widely expressed flp in Caenorhabditis elegans; (iii) in species expressing both flp-11 and flp-32, flp-11 displays a conserved, restricted expression pattern across nematode clades and lifestyles; (iv) in species expressing both flp-11 and flp-32, flp-32 expression is more widespread and less conserved than flp-11; (v) in species expressing only flp-11, the flp-11 expression profile is more similar to the flp-32 profile observed in species expressing both; and (vi) FLP-11 peptides inhibit motor function in multiple nematode species. The biological significance and evolutionary origin of flp-11 and -32 peptide duplication remains unclear despite attempts to identify a common ancestor; this may become clearer as the availability of genomic data improves. This work provides insight into the complexity of the neuropeptidergic system in nematodes, and begins to examine how nematodes may compensate for structural neuronal simplicity. From a parasite control standpoint, this work underscores the importance of basic biological data, and has

  2. Scanning electron microscopy of the predatory ability of agents of the biocontrol of nematodes/ Microscopia eletrônica de varredura da habilidade predatória de agentes do biocontrole de nematóides

    Directory of Open Access Journals (Sweden)

    João Carlos de Oliveira

    2001-08-01

    Full Text Available Nematode-trapping fungi have been studied as a promising alternative to control bovine gastrointestinal parasites and plant parasitic nematodes. Some encouraging results have been achieved with some species, by many researchers. Nematophagous fungi such as Arthrobotrys javanica, Dactylella leptospora, Monacrosporium eudermatum, M. robustum e Nematoctonus campylosporus were isolated from soil samples collected from different crops and agronomic environments proceeding from varies places in Brazil, making use of soil spreading methods. These fungi species were isolated at the Center of Animal Parasitology (CPPAR at UNESP/FCAV, Campus Jaboticabal – SP. The predatory ability of these fungi, on free living nematodes (Panagrellus sp. was documented at the Scanning Electron Microscopy Lab. The objectives of this work were to document, through Scanning Electron Microscopy (SEM, the morphological structures of these fungi, such as: capturing structures, size, form, septation of the conidia, connection clamp, exclusively on N. campylosporus, as well as the free-living nematodes captured by these fungi.Fungos nematófagos têm sido estudados como uma alternativa promissora para o manejo de nematóides de plantas e parasitos gastrintestinais de bovinos. Resultados encorajadores têm sido obtidos com algumas espécies, por vários pesquisadores. A partir de amostras de solo coletadas em diferentes culturas e agroecossistemas provenientes de diversas localidades do Brasil, foram isolados, pelo método de espalhamento de solo, os fungos nematófagos Arthrobotrys javanica, Dactylella leptospora, Monacrosporium eudermatum, M. robustum e Nematoctonus campylosporus, no Centro de Pesquisas em Sanidade Animal (CPPAR da UNESP/FCAV, Câmpus de Jaboticabal - SP, e a habilidade predatória destes fungos sobre o nematóide de vida livre Panagrellus sp. foi estudada no Laboratório de Microscopia Eletrônica de Varredura. Este trabalho teve como objetivo documentar ao

  3. Cereal Cyst Nematode (Heterodera avenae) on Oats. II. Early Root Development and Nematode Tolerance

    OpenAIRE

    Volkmar, K. M.

    1989-01-01

    The effect of Heterodera avenae infestation on early seminal and lateral root growth was examined in four oat genotypes differing in tolerance to H. avenae. Recently emerged seminal roots were inoculated with a range of H. avenae larval densities, then transferred a hydroponic system to remove the effect of later nematode penetration on root development. Intolerance to H. avenae was assessed in terms of impairment of seminal root extension resulting in fewer primary lateral roots emerging fro...

  4. Condensed tannins act against cattle nematodes

    DEFF Research Database (Denmark)

    Novobilský, Adam; Mueller-Harvey, Irene; Thamsborg, Stig Milan

    2011-01-01

    The use of natural plant anthelmintics was suggested as a possible alternative control of gastrointestinal nematodes (GIN) in ruminants. Direct anthelmintic effects of tannin-containing plants have already been shown in sheep and goat GIN. These anthelmintic properties are mainly associated...... with condensed tannins. In the present study, we evaluated possible in vitro effects of three tannin-containing plants against bovine GIN. Effects of Onobrychis viciifolia, Lotus pedunculatus and Lotus corniculatus condensed tannin (CT) extracts on Cooperia oncophora and Ostertagia ostertagi were determined...... (third stage larvae) was also affected by CT extracts from all three plants. In both in vitro assays, extracts with added polyvinylpolypyrrolidone, an inhibitor of tannins, generated almost the same values as the negative control; this confirms the role of CT in the anthelmintic effect of these plant...

  5. Management of crotalaria and pigeon pea for control of yam nematode diseases Manejo da crotalária e do guandu no controle de nematoses do inhame

    Directory of Open Access Journals (Sweden)

    Marlon da Silva Garrido

    2008-09-01

    Full Text Available Management of plant-parasitic nematodes with the use of nematicides has not been recommended for small farmers that grow yam in the Northeastern region of Brazil, due to its high cost and residue toxicity. The use of plants with antagonistic effect to nematodes and green manure which improves soil chemical, physical and biological characteristics can be a viable and low cost alternative to control parasitic nematodes. This work aimed to evaluate the effect of crotalaria (Crotalaria juncea and pigeon pea (Cajanus cajan plants on the control of yam nematodes. Three experiments were carried out. The first was conducted under in vitro conditions to evaluate the nematostatic and nematicide effect of extracts from fresh and dry matter of the above ground parts of crotalaria, pigeon pea, and the combination of both. The second experiment was carried out under greenhouse conditions to evaluate the effect of soil amendment with crotalaria, pigeon pea, and the combination of both in the infectivity of Scutellonema bradys, using tomato plants as the host plant. The third experiment was conducted under field conditions to evaluate the effect of crotalaria, pigeon pea, and the combination of both, cultivated between yam planting rows and incorporated to soil surface, on yam nematodes. The aqueous extract obtained form fresh matter of crotalaria had a nematicide effect of 100% for S. bradys. Extracts from dry matter of both crotalaria and pigeon pea did not have any nematicide effect, but had a nematostatic effect. Incorporation of crotalaria to soil inhibited infectivity of S. bradys in tomato seedlings. These results showed that planting crotalaria alone or in combination with pigeon pea, between the yam planting rows, is an efficient method for controlling S. bradys and Rotylenchulus reniformis associated with yams. Crotalaria can be used for controlling these plant-parasitic nematodes in soil.O manejo de fitomenatóides com o uso de nematicidas não tem

  6. Prevalence of common gastro-intestinal nematode infections in ...

    African Journals Online (AJOL)

    ACSS

    (GIN) infection and identified the common GIN parasites in commercial goat production in. Central Uganda. .... Table 1. Prevalence of gastro-intestinal nematode parasites in goats in Central Uganda .... ILCA, Addis Ababa, Ethiopia. pp. 40-76.

  7. Integrated management of root-knot nematode (Meloidogyne ...

    African Journals Online (AJOL)

    Integrated management of root-knot nematode (Meloidogyne incognita) for tomato production and productivity. Bayuh Belay1* ... important food and cash crop of the farmers and is ...... some part of the research budget without any reservation.

  8. Potential Nematode Alarm Pheromone Induces Acute Avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Zhou, Ying; Loeza-Cabrera, Mario; Liu, Zheng; Aleman-Meza, Boanerges; Nguyen, Julie K; Jung, Sang-Kyu; Choi, Yuna; Shou, Qingyao; Butcher, Rebecca A; Zhong, Weiwei

    2017-07-01

    It is crucial for animal survival to detect dangers such as predators. A good indicator of dangers is injury of conspecifics. Here we show that fluids released from injured conspecifics invoke acute avoidance in both free-living and parasitic nematodes. Caenorhabditis elegans avoids extracts from closely related nematode species but not fruit fly larvae. The worm extracts have no impact on animal lifespan, suggesting that the worm extract may function as an alarm instead of inflicting physical harm. Avoidance of the worm extract requires the function of a cGMP signaling pathway that includes the cGMP-gated channel TAX-2/TAX-4 in the amphid sensory neurons ASI and ASK. Genetic evidence indicates that the avoidance behavior is modulated by the neurotransmitters GABA and serotonin, two common targets of anxiolytic drugs. Together, these data support a model that nematodes use a nematode-specific alarm pheromone to detect conspecific injury. Copyright © 2017 by the Genetics Society of America.

  9. Variation in estuarine littoral nematode populations over three spatial scales

    Science.gov (United States)

    Hodda, M.

    1990-04-01

    The population characteristics of the nematode fauna from five replicate cores taken over four seasons at nine sites within mangroves, at three different estuaries on the south-east coast of Australia, are compared. Using cluster analysis, principal co-ordinate analysis and other statistical techniques, the variation in nematode populations is identified as arising from several sources: temperature changes between the more northerly and southerly estuaries (5%); changes in grain size and organic content of the sediment between sites (22%); changes between sites in the frequency of samples containing certain types of food, particularly associated with pools of water and surface topography (30%); stochastic changes in nematode populations within individual samples, probably caused by small scale spatial and temporal variability in food sources (35%); and seasonal changes at all the sites and estuaries (8%). The implications of this pattern of variation for the biology of the nematodes is discussed.

  10. Anisakid nematodes associated with aquatic orga- nisms and ...

    African Journals Online (AJOL)

    spamer

    and respond to long- and medium-term physical, chemical and biological .... that the formation of fibrotic capsules around nematode larvae might prevent further ... capabilities and function primarily in the encapsulation of large parasitic ...

  11. Systemic induced tolerance against root-knot nematodes in rice

    African Journals Online (AJOL)

    user

    Rice plantlets were randomly grown in laboratory, sprayed with hormones and riboflavin .... between riboflavin, SA, JA and ET pathways in rice-nematodes interaction, ..... oxidative damage caused by aging as well as biotic and abiotic stress.

  12. Challenges for mass production of nematodes in submerged culture.

    Science.gov (United States)

    de la Torre, Mayra

    2003-08-01

    Nematodes of Steinernema and Heterorhabditis genera are used as agents in insect biocontrol programs. They are associated with specific bacteria which are also involved in the mechanism of pathogenicity and which are consumed by nematodes as living food. S. feltiae has various developmental stages in its life cycle, including four juvenile stages, adults and the free living form. During mating, males coil themselves around the female, which is around 1 cm long. Successful commercialization of nematode-bacteria biocontrol products depends on the ability to produce sufficient quantities of these products at competitive prices for a full pest control program. This could be feasible if high cell density submerged cultures are designed and implemented; however, major problems related to nematodes mass production in a bioreactor remain unsolved due to the lack of knowledge about the physiological aspects of the nematode, bacteria and nematode-bacteria association, interaction between the three phases present in the bioreactor (liquid, gas, nematodes-bacteria), possibility of mating under hydrodynamic stress conditions, etc. We have found that the two most important engineering aspects to take into account the mass propagation of nematodes are oxygen transfer rate and hydrodynamics to allow mating and to avoid mechanical damage of juveniles in stage 2. This article focuses on several aspects related to the fermentation system such as kinetics of growth, shear stress, hydrodynamics fields in the bioreactor and oxygen demand. Also, results published by other groups, together with those of our own, will be discussed in relation to the main challenges found during the fermentation process.

  13. Biocontrol: Bacillus penetrans and Related Parasites of Nematodes

    OpenAIRE

    Sayre, R. M.

    1980-01-01

    Bacillus penetrans Mankau, 1975, previously described as Duboscqia penetrans Thorne 1940, is a candidate agent for biocontrol of nematodes. This review considers the life stages of this bacterium: vegetative growth phase, colony fragmentation, sporogenesis, soil phase, spore attachment, and penetration into larvae of root-knot nematodes. The morphology of the microthallus colonies and the unusual external features of the spore are discussed. Taxonomic affinities with the actinomycetes, partic...

  14. Nematodes from terrestrial and freshwater habitats in the Arctic

    Science.gov (United States)

    2014-01-01

    Abstract We present an updated list of terrestrial and freshwater nematodes from all regions of the Arctic, for which records of properly identified nematode species are available: Svalbard, Jan Mayen, Iceland, Greenland, Nunavut, Northwest territories, Alaska, Lena River estuary, Taymyr and Severnaya Zemlya and Novaya Zemlya. The list includes 391 species belonging to 146 genera, 54 families and 10 orders of the phylum Nematoda. PMID:25197239

  15. Targeted mutagenesis in a human-parasitic nematode

    Science.gov (United States)

    Gang, Spencer S.; Castelletto, Michelle L.

    2017-01-01

    Parasitic nematodes infect over 1 billion people worldwide and cause some of the most common neglected tropical diseases. Despite their prevalence, our understanding of the biology of parasitic nematodes has been limited by the lack of tools for genetic intervention. In particular, it has not yet been possible to generate targeted gene disruptions and mutant phenotypes in any parasitic nematode. Here, we report the development of a method for introducing CRISPR-Cas9-mediated gene disruptions in the human-parasitic threadworm Strongyloides stercoralis. We disrupted the S. stercoralis twitchin gene unc-22, resulting in nematodes with severe motility defects. Ss-unc-22 mutations were resolved by homology-directed repair when a repair template was provided. Omission of a repair template resulted in deletions at the target locus. Ss-unc-22 mutations were heritable; we passed Ss-unc-22 mutants through a host and successfully recovered mutant progeny. Using a similar approach, we also disrupted the unc-22 gene of the rat-parasitic nematode Strongyloides ratti. Our results demonstrate the applicability of CRISPR-Cas9 to parasitic nematodes, and thereby enable future studies of gene function in these medically relevant but previously genetically intractable parasites. PMID:29016680

  16. Relationship between production, nematodes and "redness" in strawberries

    Directory of Open Access Journals (Sweden)

    Paula Nogueira Curi

    2016-08-01

    Full Text Available ABSTRACT: In recent years "redness" has increasingly appeared in strawberry plants with leaves taking on a reddish color. No causal agent has been associated with plants. Since strawberries presented problems due to the incidence of nematodes, the purpose of this study was to look at the relationship between production, resistance to the Meloidogyne hapla nematode and the "redness" symptom in strawberry cultivars. Two experiments were performed, both with the 'Camino Real', 'Festival', 'Oso Grande', 'Albion' and 'Camarosa' cultivars. The first experiment was performed in the field, where the following were evaluated: strawberry production, fruit quality, macro and micronutrient contents in fruit and leaves, percentage of plant survival, incidence of nematodes, quantity of eggs in the roots and juveniles in the soil, and the incidence of Botrytis cinerea . In the second experiment, the strawberries were transplanted into pots and filled with pinus bark-based commercial substrate. Half the pots were inocculated with Meloidogyne hapla . Cultivars presented differences in fruit production and also in the incidence of "redness". Lowest performance in production was related to the high incidence of the nematode Meloidogyne hapla. 'Oso Grande' and 'Albion' presented nematode-resistant behavior. It was possible find a relationship between the incidence of the Meloidogyne hapla nematode, and the incidence of "redness" only 'Camino Real' cultivar.

  17. Communities of terrestrial nematodes after different approaches to heathland restoration

    Science.gov (United States)

    Radochova, Petra; Frouz, Jan

    2016-04-01

    Since the 20th century, the distribution of European heathlands rapidly decreased due to agricultural intensification, heavy use of artificial fertilizers or acidification (Aerts & Heil, 1993). Therefore, various attempts of heathland restoration are under way in these days. Analysis of nematode community composition can be one of the tools suitable for succession evaluation (Ferris et al., 2001). In 2011, 2013 and 2014, soil samples were collected from heathland restoration experiment (launched in 2011) where different restoration methods were applied in a 3 × 3 factorial experiment; existing heathlands were also sampled to identify the target community both in dry and wet heathland. A total of 60 samples of extracted nematodes were analysed for absolute abundance, trophic groups, and genera dominance. Various indices were calculated to describe the nematode community. We were able to prove faster development of wet heathlands towards the target community. However, because of large data variability, there was no significant difference between treatments. Development of wet and dry heathlands differed also in increased proportion of omniphagous nematodes in 2013 and predators in 2014 in dry heathlands. After three years of heathland restoration, nematode community has not yet reached parameters of the target community. References Aerts, R., Heil, G. W., 1993. Heathlands: patterns and processes in a changing environment, 1st ed, Geobotany: 20. Springer Netherlands, Dordrecht, p. 229. Ferris, H., Bongers, T., De Goede, R. G. M., 2001. A framework for soil food web diagnostics: Extension of the nematode faunal analysis oncept. Appl. Soil Ecol. 18, 13-29.

  18. Discovery of genomic intervals that underlie nematode responses to benzimidazoles.

    Science.gov (United States)

    Zamanian, Mostafa; Cook, Daniel E; Zdraljevic, Stefan; Brady, Shannon C; Lee, Daehan; Lee, Junho; Andersen, Erik C

    2018-03-01

    Parasitic nematodes impose a debilitating health and economic burden across much of the world. Nematode resistance to anthelmintic drugs threatens parasite control efforts in both human and veterinary medicine. Despite this threat, the genetic landscape of potential resistance mechanisms to these critical drugs remains largely unexplored. Here, we exploit natural variation in the model nematodes Caenorhabditis elegans and Caenorhabditis briggsae to discover quantitative trait loci (QTL) that control sensitivity to benzimidazoles widely used in human and animal medicine. High-throughput phenotyping of albendazole, fenbendazole, mebendazole, and thiabendazole responses in panels of recombinant lines led to the discovery of over 15 QTL in C. elegans and four QTL in C. briggsae associated with divergent responses to these anthelmintics. Many of these QTL are conserved across benzimidazole derivatives, but others show drug and dose specificity. We used near-isogenic lines to recapitulate and narrow the C. elegans albendazole QTL of largest effect and identified candidate variants correlated with the resistance phenotype. These QTL do not overlap with known benzimidazole target resistance genes from parasitic nematodes and present specific new leads for the discovery of novel mechanisms of nematode benzimidazole resistance. Analyses of orthologous genes reveal conservation of candidate benzimidazole resistance genes in medically important parasitic nematodes. These data provide a basis for extending these approaches to other anthelmintic drug classes and a pathway towards validating new markers for anthelmintic resistance that can be deployed to improve parasite disease control.

  19. A metagenetic approach to determine the diversity and distribution of cyst nematodes at the level of the country, the field and the individual.

    Science.gov (United States)

    Eves-van den Akker, Sebastian; Lilley, Catherine J; Reid, Alex; Pickup, Jon; Anderson, Eric; Cock, Peter J A; Blaxter, Mark; Urwin, Peter E; Jones, John T; Blok, Vivian C

    2015-12-01

    Distinct populations of the potato cyst nematode (PCN) Globodera pallida exist in the UK that differ in their ability to overcome various sources of resistance. An efficient method for distinguishing between populations would enable pathogen-informed cultivar choice in the field. Science and Advice for Scottish Agriculture (SASA) annually undertake national DNA diagnostic tests to determine the presence of PCN in potato seed and ware land by extracting DNA from soil floats. These DNA samples provide a unique resource for monitoring the distribution of PCN and further interrogation of the diversity within species. We identify a region of mitochondrial DNA descriptive of three main groups of G. pallida present in the UK and adopt a metagenetic approach to the sequencing and analysis of all SASA samples simultaneously. Using this approach, we describe the distribution of G. pallida mitotypes across Scotland with field-scale resolution. Most fields contain a single mitotype, one-fifth contain a mix of mitotypes, and less than 3% contain all three mitotypes. Within mixed fields, we were able to quantify the relative abundance of each mitotype across an order of magnitude. Local areas within mixed fields are dominated by certain mitotypes and indicate towards a complex underlying 'pathoscape'. Finally, we assess mitotype distribution at the level of the individual cyst and provide evidence of 'hybrids'. This study provides a method for accurate, quantitative and high-throughput typing of up to one thousand fields simultaneously, while revealing novel insights into the national genetic variability of an economically important plant parasite. © 2015 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  20. Tomato transgenic plants expressing hairpin construct of a nematode protease gene conferred enhanced resistance to root-knot nematodes

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Dutta

    2015-04-01

    Full Text Available Root-knot nematodes (Meloidogyne incognita cause substantial yield losses in vegetables worldwide, and are difficult to manage. Continuous withdrawal of environmentally-harmful nematicides from the global market warrants the need for novel nematode management strategies. Utility of host-delivered RNAi has been demonstrated in several plants (Arabidopsis, tobacco and soybean that exhibited resistance against root-knot and cyst nematodes. Herein, a M. incognita-specific protease gene, cathepsin L cysteine proteinase (Mi-cpl-1, was targeted to generate tomato transgenic lines to evaluate the genetically modified nematode resistance. In vitro knockdown of Mi-cpl-1 gene led to the reduced attraction and penetration of M. incognita in tomato, suggesting the involvement of Mi-cpl-1 in nematode parasitism. Transgenic expression of the RNAi construct of Mi-cpl-1 gene resulted in 60-80% reduction in infection and multiplication of M. incognita in tomato. Evidence for in vitro and in vivo silencing of Mi-cpl-1 was confirmed by expression analysis using quantitative PCR. Our study demonstrates that Mi-cpl-1 plays crucial role during plant-nematode interaction and plant-mediated downregulation of this gene elicits detrimental effect on M. incognita development, reinforcing the potential of RNAi technology for management of phytonematodes in crop plants.

  1. Dexamethasone suppression test

    Science.gov (United States)

    DST; ACTH suppression test; Cortisol suppression test ... During this test, you will receive dexamethasone. This is a strong man-made (synthetic) glucocorticoid medicine. Afterward, your blood is drawn ...

  2. Deconstructing continuous flash suppression

    OpenAIRE

    Yang, Eunice; Blake, Randolph

    2012-01-01

    In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in co...

  3. RNA-Seq reveals the molecular mechanism of trapping and killing of root-knot nematodes by nematode-trapping fungi.

    Science.gov (United States)

    Pandit, Ramesh; Patel, Reena; Patel, Namrata; Bhatt, Vaibhav; Joshi, Chaitanya; Singh, Pawan Kumar; Kunjadia, Anju

    2017-04-01

    Nematode-trapping fungi are well known for their inherent potential to trap and kill nematodes using specialized trapping devices. However, the molecular mechanisms underlying the trapping and subsequent processes are still unclear. Therefore, in this study, we examined differential genes expression in two nematode-trapping fungi after baiting with nematode extracts. In Arthrobotrys conoides, 809 transcripts associated with diverse functions such as signal transduction, morphogenesis, stress response and peroxisomal proteins, proteases, chitinases and genes involved in the host-pathogen interaction showed differential expression with fold change (>±1.5 fold) in the presence of nematode extract with FDR (p-value nematode-trapping fungi for its host. The findings illustrate the molecular mechanism of fungal parasitism in A. conoides which may be helpful in developing a potential biocontrol agent against parasitic nematodes.

  4. Effects of abscisic acid and nitric oxide on trap formation and trapping of nematodes by the fungus Drechslerella stenobrocha AS6.1.

    Science.gov (United States)

    Xu, Ling-Ling; Lai, Yi-Ling; Wang, Lin; Liu, Xing-Zhong

    2011-02-01

    The in vitro effects of abscisic acid (ABA) and nitric oxide (NO) on the nematode-trapping fungus Drechslerella stenobrocha AS6.1 were examined. The average number of traps (constricting rings) per colony and the percentage of nematodes (Caenorhabditis elegans) trapped were greatly increased by addition of ABA but greatly suppressed by addition of sodium nitroprusside (SNP, an NO donor) to corn meal agar. The suppressive effect of SNP was not negated by addition of an NO synthase competitive inhibitor (l-naphthylacetic acid, L-NNA) or an NO-specific scavenger [2-(4-carboxyphenyl)-4,4, 5,5-tetramethylimidazoline-1-oxyl-3-oxide, cPTIO]. When added without SNP, however, L-NNA and cPTIO caused moderate increases in trap number and trapping. The results indicate that the trap formation and nematode-trapping ability of D. stenobrocha were enhanced by ABA but decreased by exogenous NO. Copyright © 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  5. The entomopathogenic nematode Heterorhabditis megidis: host searching behaviour, infectivity and reproduction

    NARCIS (Netherlands)

    Boff, M.I.C.

    2001-01-01

    Entomopathogenic nematodes in the families Heterorhabditidae and Steinernematidae have considerable potential as biological control agents of soil-inhabiting insect pests. Attributes making these nematodes ideal biological control agents include their broad host range, high virulence,

  6. Characterization of soil nematode communities in three cropping systems through morphological and DNA metabarcoding approaches

    Science.gov (United States)

    Communities of soil nematodes impact ecosystem functions, including plant growth, decomposition, and nutrient cycling, all of which are vital processes in agriculture. We used complementary morphological and DNA metabarcoding analyses to characterize soil nematode communities in three cropping syste...

  7. Plant and soil nematodes from Lokchao Yangoupokpi Wildlife Sanctuary, Manipur, India

    OpenAIRE

    N. Mohilal; M. Pramodini; L. Bina

    2009-01-01

    In the present study soil samples were collected from Lokchao Yangoupokpi Wildlife Sanctuary to investigate about what nematode species are associated with different plant hosts. This study shows rich nematode diversity in the sanctuary.

  8. Plant and soil nematodes from Lokchao Yangoupokpi Wildlife Sanctuary, Manipur, India

    Directory of Open Access Journals (Sweden)

    N. Mohilal

    2009-03-01

    Full Text Available In the present study soil samples were collected from Lokchao Yangoupokpi Wildlife Sanctuary to investigate about what nematode species are associated with different plant hosts. This study shows rich nematode diversity in the sanctuary.

  9. Survival and Movement of Insect Parasitic Nematodes in Poultry Manure and Their Infectivity Against Musca domestica

    OpenAIRE

    Georgis, Ramon; Mullens, Bradley A.; Meyer, Jeffery A.

    1987-01-01

    Survival, infectivity, and movement of three insect parasitic nematodes (Steinernema feltiae All strain, S. bibionis SN strain, and Heterorhabditis heliothidis NC strain) in poultry manure were tested under laboratory conditions. The majority (70-100%) of the nematodes died within 18 hours after exposure to the manure. Nematodes exposed to manure slurry for 6 hours killed at least 95% of the house fly larvae, Musca domestica, but nematodes exposed for 12 hours achieved less than 40% larval mo...

  10. The FMRFamide-like peptide family in nematodes

    Directory of Open Access Journals (Sweden)

    Katleen ePeymen

    2014-06-01

    Full Text Available In the three decades since the FMRFamide peptide was isolated from the mollusk Macrocallista nimbosa, structurally similar peptides sharing a C-terminal RFamide motif have been identified across the animal kingdom. FMRFamide-like peptides (FLPs represent the largest known family of neuropeptides in invertebrates. In the phylum Nematoda, at least 32 flp genes are classified, making the FLP system of nematodes unusually complex. The diversity of the nematode FLP complement is most extensively mapped in Caenorhabditis elegans, where over 70 FLPs have been predicted. FLPs have shown to be expressed in the majority of the 302 C. elegans neurons including interneurons, sensory and motor neurons. The vast expression of FLPs is reflected in the broad functional repertoire of nematode FLP signaling, including neuroendocrine and neuromodulatory effects on locomotory activity, reproduction, feeding, and behavior. In contrast to the many identified nematode FLPs, only few peptides have been assigned a receptor and there is the need to clarify the pathway components and working mechanisms of the FLP signaling network. Here, we review the diversity, distribution, and functions of FLPs in nematodes.

  11. Smart Parasitic Nematodes Use Multifaceted Strategies to Parasitize Plants

    Directory of Open Access Journals (Sweden)

    Muhammad A. Ali

    2017-10-01

    Full Text Available Nematodes are omnipresent in nature including many species which are parasitic to plants and cause enormous economic losses in various crops. During the process of parasitism, sedentary phytonematodes use their stylet to secrete effector proteins into the plant cells to induce the development of specialized feeding structures. These effectors are used by the nematodes to develop compatible interactions with plants, partly by mimicking the expression of host genes. Intensive research is going on to investigate the molecular function of these effector proteins in the plants. In this review, we have summarized which physiological and molecular changes occur when endoparasitic nematodes invade the plant roots and how they develop a successful interaction with plants using the effector proteins. We have also mentioned the host genes which are induced by the nematodes for a compatible interaction. Additionally, we discuss how nematodes modulate the reactive oxygen species (ROS and RNA silencing pathways in addition to post-translational modifications in their own favor for successful parasitism in plants.

  12. Application of entomopathogenic nematode-infected cadavars from hard-bodied arthropods for insect suppression

    OpenAIRE

    2003-01-01

    Pesticidal and/or antimicrobial biological agent-infected hard-bodied arthropod cadavers, such as from the family Tenebrionidae are used to control pest and/or microbial infestations in agriculture, commercial and urban environments.

  13. 78 FR 27856 - Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY

    Science.gov (United States)

    2013-05-13

    .... APHIS-2012-0079] Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY... nematode regulations by removing areas in Livingston and Steuben Counties in New York from the list of... nematode, and we determined that regulation of these areas was no longer necessary. As a result of that...

  14. 7 CFR 301.85-9 - Movement of live golden nematodes.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

  15. 78 FR 1713 - Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY

    Science.gov (United States)

    2013-01-09

    ...-0079] Golden Nematode; Removal of Regulated Areas in Livingston and Steuben Counties, NY AGENCY: Animal... are amending the golden nematode regulations by removing areas in Livingston and Steuben Counties in... areas in these two counties are free of golden nematode, and we have determined that regulation of these...

  16. Mechanisms Involved in Nematode Control by Endophytic Fungi.

    Science.gov (United States)

    Schouten, Alexander

    2016-08-04

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood but most likely multifactorial. This knowledge gap obstructs the progress regarding the development of endophytes or endophyte-derived constituents into biocontrol agents. In part, this may be caused by the fact that endophytic fungi form a rather heterogeneous group. By combining the knowledge of the currently characterized antagonistic endophytic fungi and their effects on nematode behavior and biology with the knowledge of microbial competition and induced plant defenses, the various mechanisms by which this nematode antagonism operates or may operate are discussed. Now that new technologies are becoming available and more accessible, the currently unresolved mechanisms can be studied in greater detail than ever before.

  17. Induction of mutations for nematode resistance in tomato

    International Nuclear Information System (INIS)

    Alameddine, A.

    1976-01-01

    The objective of this work is to develop resistance to root-knot nematodes in tomato by induction, selection and utilization of the newly created resistant strains. Seeds of two varieties of tomato Lycopersicon esculentum L., namely Amcopack and Supermarmande, were subjected to various doses of gamma rays ranging from 10 Krads to 40 Krads in an effort to gain resistance to Meloidogyne incognita Chitwood, the prevalent species of nematodes in Lebanon. The variety Supermarmande seemed not to be affected by irradiation while Amcopack gained some resistance with a corresponding increase in the dose of radiation. The data suggest that in a variety like Amcopack, irradiation may stimulate resistance while in others like Supermarmande, susceptibility is not reduced with a corresponding increase of dosage. Those alterations in reaction within varieties may be due to genetic differences which allow some varieties to acquire resistance to nematodes when exposed to certain dosages, while others to suffer seriously due to sensitivity. (author)

  18. Small-molecule pheromones and hormones controlling nematode development.

    Science.gov (United States)

    Butcher, Rebecca A

    2017-05-17

    The existence of small-molecule signals that influence development in Caenorhabditis elegans has been known for several decades, but only in recent years have the chemical structures of several of these signals been established. The identification of these signals has enabled connections to be made between these small molecules and fundamental signaling pathways in C. elegans that influence not only development but also metabolism, fertility, and lifespan. Spurred by these important discoveries and aided by recent advances in comparative metabolomics and NMR spectroscopy, the field of nematode chemistry has the potential to expand dramatically in the coming years. This Perspective will focus on small-molecule pheromones and hormones that influence developmental events in the nematode life cycle (ascarosides, dafachronic acids, and nemamides), will cover more recent work regarding the biosynthesis of these signals, and will explore how the discovery of these signals is transforming our understanding of nematode development and physiology.

  19. Nematode spatial and ecological patterns from tropical and temperate rainforests.

    Directory of Open Access Journals (Sweden)

    Dorota L Porazinska

    Full Text Available Large scale diversity patterns are well established for terrestrial macrobiota (e.g. plants and vertebrates, but not for microscopic organisms (e.g. nematodes. Due to small size, high abundance, and extensive dispersal, microbiota are assumed to exhibit cosmopolitan distributions with no biogeographical patterns. This assumption has been extrapolated from local spatial scale studies of a few taxonomic groups utilizing morphological approaches. Recent molecularly-based studies, however, suggest something quite opposite. Nematodes are the most abundant metazoans on earth, but their diversity patterns are largely unknown. We conducted a survey of nematode diversity within three vertical strata (soil, litter, and canopy of rainforests at two contrasting latitudes in the North American meridian (temperate: the Olympic National Forest, WA, U.S.A and tropical: La Selva Biological Station, Costa Rica using standardized sampling designs and sample processing protocols. To describe nematode diversity, we applied an ecometagenetic approach using 454 pyrosequencing. We observed that: 1 nematode communities were unique without even a single common species between the two rainforests, 2 nematode communities were unique among habitats in both rainforests, 3 total species richness was 300% more in the tropical than in the temperate rainforest, 4 80% of the species in the temperate rainforest resided in the soil, whereas only 20% in the tropics, 5 more than 90% of identified species were novel. Overall, our data provided no support for cosmopolitanism at both local (habitats and large (rainforests spatial scales. In addition, our data indicated that biogeographical patterns typical of macrobiota also exist for microbiota.

  20. Nematode Spatial and Ecological Patterns from Tropical and Temperate Rainforests

    Science.gov (United States)

    Porazinska, Dorota L.; Giblin-Davis, Robin M.; Powers, Thomas O.; Thomas, W. Kelley

    2012-01-01

    Large scale diversity patterns are well established for terrestrial macrobiota (e.g. plants and vertebrates), but not for microscopic organisms (e.g. nematodes). Due to small size, high abundance, and extensive dispersal, microbiota are assumed to exhibit cosmopolitan distributions with no biogeographical patterns. This assumption has been extrapolated from local spatial scale studies of a few taxonomic groups utilizing morphological approaches. Recent molecularly-based studies, however, suggest something quite opposite. Nematodes are the most abundant metazoans on earth, but their diversity patterns are largely unknown. We conducted a survey of nematode diversity within three vertical strata (soil, litter, and canopy) of rainforests at two contrasting latitudes in the North American meridian (temperate: the Olympic National Forest, WA, U.S.A and tropical: La Selva Biological Station, Costa Rica) using standardized sampling designs and sample processing protocols. To describe nematode diversity, we applied an ecometagenetic approach using 454 pyrosequencing. We observed that: 1) nematode communities were unique without even a single common species between the two rainforests, 2) nematode communities were unique among habitats in both rainforests, 3) total species richness was 300% more in the tropical than in the temperate rainforest, 4) 80% of the species in the temperate rainforest resided in the soil, whereas only 20% in the tropics, 5) more than 90% of identified species were novel. Overall, our data provided no support for cosmopolitanism at both local (habitats) and large (rainforests) spatial scales. In addition, our data indicated that biogeographical patterns typical of macrobiota also exist for microbiota. PMID:22984536

  1. Viability and Virulence of Entomopathogenic Nematodes Exposed to Ultraviolet Radiation.

    Science.gov (United States)

    Shapiro-Ilan, David I; Hazir, Selcuk; Lete, Luis

    2015-09-01

    Entomopathogenic nematodes (EPNs) can be highly effective biocontrol agents, but their efficacy can be reduced due to exposure to environmental stress such as from ultraviolet (UV) radiation. Our objectives were to 1) compare UV tolerance among a broad array of EPN species, and 2) investigate the relationship between reduced nematode viability (after exposure to UV) and virulence. Nematodes exposed to a UV radiation (254 nm) for 10 or 20 min were assessed separately for viability (survival) and virulence to Galleria mellonella. We compared 9 different EPN species and 15 strains: Heterorhabditis bacteriophora (Baine, fl11, Oswego, and Vs strains), H. floridensis (332), H. georgiana (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All, Cxrd, DD136, and Sal strains), S. feltiae (SN), S. rarum (17C&E), and S. riobrave (355). In viability assessments, steinernematids, particularly strains of S. carpocapsae, generally exhibited superior UV tolerance compared with the heterorhabditids. However, some heterorhabditids tended to be more tolerant than others, e.g., H. megidis and H. bacteriophora (Baine) were most susceptible and H. bacteriophora (Vs) was the only heterorhabditid that did not exhibit a significant effect after 10 min of exposure. All heterorhabditids experienced reduced viability after 20 min exposure though several S. carpocapsae strains did not. In total, after 10 or 20 min exposure, the viability of seven nematode strains did not differ from their non-UV exposed controls. In virulence assays, steinernematids (particularly S. carpocapsae strains) also tended to exhibit higher UV tolerance. However, in contrast to the viability measurements, all nematodes experienced a reduction in virulence relative to their controls. Correlation analysis revealed that viability among nematode strains is not necessarily related to virulence. In conclusion, our results indicate that the impact of UV varies substantially among EPNs, and viability alone

  2. Microbeam irradiation of the C. elegans nematode

    International Nuclear Information System (INIS)

    Bertucci, Antonella; Brenner, David J.; Pocock, Roger D.J.; Randers-Pehrson, Gerhard

    2009-01-01

    The understanding of complex radiation responses in biological systems, such as non-targeted effects as represented by the bystander response, can be enhanced by the use of genetically amenable model organisms. Almost all bystander studies to date have been carried out by using conventional single-cell in vitro systems, which are useful tools to characterize basic cellular and molecular responses. A few studies have been reported in monolayer explants and bystander responses have been also investigated in a three-dimensional normal human tissue system. However, despite the well-know usefulness of in vitro models, they cannot capture the complexity of radiation responses of living systems such as animal models. To carry out in vivo studies on the bystander effect we have developed a new technique to expose living organisms using proton microbeams. We report the use of a nematode C. elegans strain with a Green Fluorescent Protein (GFP) reporter for the hsp-4 heat-shock gene as an in vivo model for radiation studies. Exposing animals to heat and chemicals stressors leads to whole body increases in the hsp-4 protein reflected by enhanced fluorescence. We report here that γ-rays also can induce stress response in a dose dependent manner. However, whole body exposure to stress agents does not allow for evaluation of distance dependent response in non targeted tissues: the so-called bystander effect. We used the RARAF microbeam to site specifically deliver 3 MeV protons to a site in the tail of young worms. GFP expression was enhanced after 24 hours in a number dependent manner at distances > 100 μm from the site of irradiation. (author)

  3. Statistical and Economic Techniques for Site-specific Nematode Management.

    Science.gov (United States)

    Liu, Zheng; Griffin, Terry; Kirkpatrick, Terrence L

    2014-03-01

    Recent advances in precision agriculture technologies and spatial statistics allow realistic, site-specific estimation of nematode damage to field crops and provide a platform for the site-specific delivery of nematicides within individual fields. This paper reviews the spatial statistical techniques that model correlations among neighboring observations and develop a spatial economic analysis to determine the potential of site-specific nematicide application. The spatial econometric methodology applied in the context of site-specific crop yield response contributes to closing the gap between data analysis and realistic site-specific nematicide recommendations and helps to provide a practical method of site-specifically controlling nematodes.

  4. Modelling nematode movement using time-fractional dynamics.

    Science.gov (United States)

    Hapca, Simona; Crawford, John W; MacMillan, Keith; Wilson, Mike J; Young, Iain M

    2007-09-07

    We use a correlated random walk model in two dimensions to simulate the movement of the slug parasitic nematode Phasmarhabditis hermaphrodita in homogeneous environments. The model incorporates the observed statistical distributions of turning angle and speed derived from time-lapse studies of individual nematode trails. We identify strong temporal correlations between the turning angles and speed that preclude the case of a simple random walk in which successive steps are independent. These correlated random walks are appropriately modelled using an anomalous diffusion model, more precisely using a fractional sub-diffusion model for which the associated stochastic process is characterised by strong memory effects in the probability density function.

  5. Deconstructing continuous flash suppression.

    Science.gov (United States)

    Yang, Eunice; Blake, Randolph

    2012-03-08

    In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in contrast detection thresholds) as a function of the visual features of the stimulus being suppressed and the stimulus evoking suppression, namely, the popular "Mondrian" CFS stimulus (N. Tsuchiya & C. Koch, 2005). First, we found that CFS differentially suppresses the spatial components of the suppressed stimulus: Observers' sensitivity for stimuli of relatively low spatial frequency or cardinally oriented features was more strongly impaired in comparison to high spatial frequency or obliquely oriented stimuli. Second, we discovered that this feature-selective bias primarily arises from the spatiotemporal structure of the CFS stimulus, particularly within information residing in the low spatial frequency range and within the smooth rather than abrupt luminance changes over time. These results imply that this CFS stimulus operates by selectively attenuating certain classes of low-level signals while leaving others to be potentially encoded during suppression. These findings underscore the importance of considering the contribution of low-level features in stimulus-driven effects that are reported under CFS.

  6. Evaluation of methyl bromide alternatives efficacy against soil-borne pathogens, nematodes and soil microbial community.

    Directory of Open Access Journals (Sweden)

    Hongwei Xie

    Full Text Available Methyl bromide (MB and other alternatives were evaluated for suppression of Fusarium spp., Phytophthora spp., and Meloidogyne spp. and their influence on soil microbial communities. Both Fusarium spp. and Phytophthora spp. were significantly reduced by the MB (30.74 mg kg-1, methyl iodide (MI: 45.58 mg kg-1, metham sodium (MS: 53.92 mg kg-1 treatments. MS exhibited comparable effectiveness to MB in controlling Meloidogyne spp. and total nematodes, followed by MI at the tested rate. By contrast, sulfuryl fluoride (SF: 33.04 mg kg-1 and chloroform (CF: 23.68 mg kg-1 showed low efficacy in controlling Fusarium spp., Phytophthora spp., and Meloidogyne spp. MB, MI and MS significantly lowered the abundance of different microbial populations and microbial biomass in soil, whereas SF and CF had limited influence on them compared with the control. Diversity indices in Biolog studies decreased in response to fumigation, but no significant difference was found among treatments in PLFA studies. Principal component and cluster analyses of Biolog and PLFA data sets revealed that MB and MI treatments greatly influenced the soil microbial community functional and structural diversity compared with SF treatment. These results suggest that fumigants with high effectiveness in suppressing soil-borne disease could significantly influence soil microbial community.

  7. The complete mitochondrial genomes of three parasitic nematodes of birds: a unique gene order and insights into nematode phylogeny

    Science.gov (United States)

    2013-01-01

    Background Analyses of mitochondrial (mt) genome sequences in recent years challenge the current working hypothesis of Nematoda phylogeny proposed from morphology, ecology and nuclear small subunit rRNA gene sequences, and raise the need to sequence additional mt genomes for a broad range of nematode lineages. Results We sequenced the complete mt genomes of three Ascaridia species (family Ascaridiidae) that infest chickens, pigeons and parrots, respectively. These three Ascaridia species have an identical arrangement of mt genes to each other but differ substantially from other nematodes. Phylogenetic analyses of the mt genome sequences of the Ascaridia species, together with 62 other nematode species, support the monophylies of seven high-level taxa of the phylum Nematoda: 1) the subclass Dorylaimia; 2) the orders Rhabditida, Trichinellida and Mermithida; 3) the suborder Rhabditina; and 4) the infraorders Spiruromorpha and Oxyuridomorpha. Analyses of mt genome sequences, however, reject the monophylies of the suborders Spirurina and Tylenchina, and the infraorders Rhabditomorpha, Panagrolaimomorpha and Tylenchomorpha. Monophyly of the infraorder Ascaridomorpha varies depending on the methods of phylogenetic analysis. The Ascaridomorpha was more closely related to the infraorders Rhabditomorpha and Diplogasteromorpha (suborder Rhabditina) than they were to the other two infraorders of the Spirurina: Oxyuridorpha and Spiruromorpha. The closer relationship among Ascaridomorpha, Rhabditomorpha and Diplogasteromorpha was also supported by a shared common pattern of mitochondrial gene arrangement. Conclusions Analyses of mitochondrial genome sequences and gene arrangement has provided novel insights into the phylogenetic relationships among several major lineages of nematodes. Many lineages of nematodes, however, are underrepresented or not represented in these analyses. Expanding taxon sampling is necessary for future phylogenetic studies of nematodes with mt genome

  8. A Simple Method to Measure Nematodes' Propulsive Thrust and the Nematode Ratchet.

    Science.gov (United States)

    Bau, Haim; Yuan, Jinzhou; Raizen, David

    2015-11-01

    Since the propulsive thrust of micro organisms provides a more sensitive indicator of the animal's health and response to drugs than motility, a simple, high throughput, direct measurement of the thrust is desired. Taking advantage of the nematode C. elegans being heavier than water, we devised a simple method to determine the propulsive thrust of the animals by monitoring their velocity when swimming along an inclined plane. We find that the swimming velocity is a linear function of the sin of the inclination angle. This method allows us to determine, among other things, the animas' propulsive thrust as a function of genotype, drugs, and age. Furthermore, taking advantage of the animals' inability to swim over a stiff incline, we constructed a sawteeth ratchet-like track that restricts the animals to swim in a predetermined direction. This research was supported, in part, by NIH NIA Grant 5R03AG042690-02.

  9. [Diversity of actinomycetes associated with root-knot nematode and their potential for nematode control].

    Science.gov (United States)

    Luo, Hong-li; Sun, Man-hong; Xie, Jian-ping; Liu, Zhi-heng; Huang, Ying

    2006-08-01

    Twenty actinomycetes were isolated from root-knot nematode eggs and females collected from 11 plant root samples infested by Meloidogyne spp.. The isolates were assigned to the genera Streptomyces, Nocardia and Pseudonocardia respectively, based on analysis of morphological characteristics, cell-wall DAPs and 16S rRNA gene sequences. 80% of them were streptomycetes. Biocontrol potential of the isolates against Meloidogyne hapla was evaluated in liquid culture in vitro. The average percentages of egg parasitism, egg hatching, and juvenile mortality were 54.1, 40.4 and 26.2, respectively. Three Streptomyces strains and one Nocardia strain with high pathogenicity in vitro were selected to determine their ability to reduce tomato root galls in greenhouse. The results demonstrated good biocontrol efficacy (31.4%-56.4%) of the strains.

  10. Differential Selection by Nematodes on an Introduced Biocontrol Fungus vs. Indigenous Fungi in Nonsterile Soil.

    Science.gov (United States)

    Kim, Tae Gwan; Knudsen, Guy R

    2018-03-15

    Trophic interactions of introduced biocontrol fungi with soil animals can bea key determinant in the fungal proliferation and activity.This study investigated trophic interaction of an introduced biocontrol fungus with soil nematodes. The biocontrol fungus Trichoderma harzianum ThzID1-M3 and the fungivorous nematode Aphelenchoides sp. (10 per gram of soil) were added to nonsterile soil, and microbial populations were monitored for 40 days. Similar results were obtained when the experiment was duplicated. ThzID1-M3 stimulated the population growth of indigenous nematodes ( p nematodes did not increase in number and the added Aphelenchoides sp. nematodes almost disappeared by day 10. With ThzID1-M3, population growth of nematodes was rapid between 5 and 10 days after treatment. ThzID1-M3 biomass peaked on day 5, dropped at day 10, and then almost disappeared at day 20, which was not influenced by the addition of nematodes.In contrast, a large quantity of ThzID1-M3 hyphae were present in a heat-treated soil in which nematodes were eliminated.Total fungal biomass in all treatments peaked on day 5 and subsequently decreased.Addition of nematodes increased the total fungal biomass ( p nematode population growth; however, hyphae of the introduced fungus when densely localized did.The results suggest that soil fungivorous nematodes are an important constraint onhyphal proliferation of fungal agents introduced into natural soils.

  11. High-throughput sequencing of nematode communities from total soil DNA extractions

    DEFF Research Database (Denmark)

    Sapkota, Rumakanta; Nicolaisen, Mogens

    2015-01-01

    nematodes without the need for enrichment was developed. Using this strategy on DNA templates from a set of 22 agricultural soils, we obtained 64.4% sequences of nematode origin in total, whereas the remaining sequences were almost entirely from other metazoans. The nematode sequences were derived from...... in previous sequence-based studies are not nematode specific but also amplify other groups of organisms such as fungi and plantae, and thus require a nematode enrichment step that may introduce biases. Results: In this study an amplification strategy which selectively amplifies a fragment of the SSU from...... a broad taxonomic range and most sequences were from nematode taxa that have previously been found to be abundant in soil such as Tylenchida, Rhabditida, Dorylaimida, Triplonchida and Araeolaimida. Conclusions: Our amplification and sequencing strategy for assessing nematode diversity was able to collect...

  12. Profiling nematode communities in unmanaged flowerbed and agricultural field soils in Japan by DNA barcode sequencing.

    Directory of Open Access Journals (Sweden)

    Hisashi Morise

    Full Text Available Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU rDNA fragments were directly amplified from each of 68 (flowerbed samples and 48 (field samples isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs, indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis.

  13. Profiling Nematode Communities in Unmanaged Flowerbed and Agricultural Field Soils in Japan by DNA Barcode Sequencing

    Science.gov (United States)

    Morise, Hisashi; Miyazaki, Erika; Yoshimitsu, Shoko; Eki, Toshihiko

    2012-01-01

    Soil nematodes play crucial roles in the soil food web and are a suitable indicator for assessing soil environments and ecosystems. Previous nematode community analyses based on nematode morphology classification have been shown to be useful for assessing various soil environments. Here we have conducted DNA barcode analysis for soil nematode community analyses in Japanese soils. We isolated nematodes from two different environmental soils of an unmanaged flowerbed and an agricultural field using the improved flotation-sieving method. Small subunit (SSU) rDNA fragments were directly amplified from each of 68 (flowerbed samples) and 48 (field samples) isolated nematodes to determine the nucleotide sequence. Sixteen and thirteen operational taxonomic units (OTUs) were obtained by multiple sequence alignment from the flowerbed and agricultural field nematodes, respectively. All 29 SSU rDNA-derived OTUs (rOTUs) were further mapped onto a phylogenetic tree with 107 known nematode species. Interestingly, the two nematode communities examined were clearly distinct from each other in terms of trophic groups: Animal predators and plant feeders were markedly abundant in the flowerbed soils, in contrast, bacterial feeders were dominantly observed in the agricultural field soils. The data from the flowerbed nematodes suggests a possible food web among two different trophic nematode groups and plants (weeds) in the closed soil environment. Finally, DNA sequences derived from the mitochondrial cytochrome oxidase c subunit 1 (COI) gene were determined as a DNA barcode from 43 agricultural field soil nematodes. These nematodes were assigned to 13 rDNA-derived OTUs, but in the COI gene analysis were assigned to 23 COI gene-derived OTUs (cOTUs), indicating that COI gene-based barcoding may provide higher taxonomic resolution than conventional SSU rDNA-barcoding in soil nematode community analysis. PMID:23284767

  14. Trigonella foenum-graecum (fenugreek-mediated suppression of Meloidogyne javanica in mungbean

    Directory of Open Access Journals (Sweden)

    Tayyaba Zia

    2013-12-01

    Full Text Available Soil amendments with powdered seeds of Trigonella foenum - graecum (fenugreek caused soil suppressiveness against Meloidogyne javanica. Decomposed seeds of fenugreek caused marked reduction in nematode population densities and subsequent root-knot development as compared to the aqueous extract of the seeds indicating that some indirect factors are involved in the suppression of root-knot nematode. Both decomposed seeds and aqueous extracts enhanced plant height and fresh weights of shoot whereas root growth remained uninfluenced. Changes in fungal communities associated with nematode control were studied by comparing population numbers of fungi in the soil and in internal root tissues (endorhiza in non-amended and fenugreekamended soils. Acremonium sp., Chaetomium globosum, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani were found to colonize inner root tissues of mungbean. Acremonium sp., C. globosum and F.solani were isolated in a relatively higher frequency from roots growing in the amended soils while M. phaseolina and R. solani colonized greatly in roots growing in non-amended soil. Of the fungi isolated from soils, Penicillium brefaldianum caused maximum juvenile mortality of M.javanica whereas F.solani caused greatest inhibition of egg hatch.

  15. The dynamics of nematode infections of farmed ruminants

    NARCIS (Netherlands)

    Roberts, M.G.; Heesterbeek, J.A.P.

    1995-01-01

    In this paper the dynamics and control of nematode parasites of farmed ruminants are discussed via a qualitative analysis of a differential equation model. To achieve this a quantity, 'the basic reproduction quotient' (Q0), whose definition coincides with previous definitions of R0 for

  16. Foraging behavior and virulence of some entomopathogenic nematodes

    Directory of Open Access Journals (Sweden)

    Manana A. Lortkipanidze

    2016-06-01

    Full Text Available At present the biological control as a pest control technology is becoming more desirable. Biological formulations on basis of entomopathogenic nematodes are one of the effective means for the protection of agricultural and forest plants from harmful insects. Nowadays, the use of entomopathogenic nematodes as biological control agents is a key component in IPM system. The foraging strategies of entomopathogenic nematodes (EPNs vary between species. This variation is consistent with use of different foraging strategies between ambush, cruise and intermediate to find their host insects. In order to ambush prey, some species of EPNs nictate, or raise their bodies of the soil surface so they are better poised to attach passing insects, other species adopt a cruising strategy and rarely nictate. Some species adopt an intermediate strategy between ambush and cruise. We compared in laboratory the foraging strategies of the entomopathogenic nematode species: Steinernema carpocapsae, Heterorhabditis bacteriophora and the recently described species Steinernema tbilisiensis and assessed their virulence against mealworm beetle, Tenebrio molitor L. (Coleoptera: Tenebrionidae. The tests showed that S. tbilisiensis adopts both foraging strategies.

  17. Pack hunting by a common soil amoeba on nematodes

    NARCIS (Netherlands)

    Geisen, Stefan; Rosengarten, J.; Koller, R.; Mulder, Christian; Urich, T.; Bonkowski, M.

    2015-01-01

    Soils host the most complex communities on Earth,
    including the most diverse and abundant eukaryotes,
    i.e. heterotrophic protists. Protists are generally con-
    sidered as bacterivores, but evidence for negative
    interactions with nematodes both from laboratory and
    field studies

  18. A critique of current methods in nematode taxonomy | Abebe ...

    African Journals Online (AJOL)

    In the past few decades, there have been efforts to integrate molecular methods and digital 3D image-capturing technology in nematode taxonomy, the former to enhance the accuracy of identification of such a taxonomically challenging group and the latter to communicate morphological data. While the employment of ...

  19. Nematode Infections Are Risk Factors for Staphylococcal Infection in Children

    Directory of Open Access Journals (Sweden)

    Sandra F Moreira-Silva

    2002-04-01

    Full Text Available Nematode infection may be a risk factor for pyogenic liver abscess in children and we hypothesized that the immunomodulation induced by those parasites would be a risk factor for any staphylococcal infection in children. The present study was designed to compare, within the same hospital, the frequency of intestinal nematodes and Toxocara infection in children with and without staphylococcal infections. From October 1997 to February 1998, 80 children with staphylococcal infection and 110 children with other diseases were submitted to fecal examination, serology for Toxocara sp., evaluation of plasma immunoglobulin levels, and eosinophil counts. Mean age, gender distribution, birthplace, and socioeconomic conditions did not differ significantly between the two groups. Frequency of intestinal nematodes and positive serology for Toxocara, were remarkably higher in children with staphylococcal infections than in the non-staphylococcal group. There was a significant correlation between intestinal nematodes or Toxocara infection and staphylococcal infection in children, reinforced by higher eosinophil counts and higher IgE levels in these children than in the control group. One possible explanation for this association would be the enhancement of bacterial infection by the immunomodulation induced by helminth infections, due to strong activation of the Th2 subset of lymphocytes by antigens from larvae and adult worms.

  20. Human Intraocular Filariasis Caused by Dirofilaria sp. Nematode, Brazil

    Science.gov (United States)

    Diniz, Daniel G.; Dantas-Torres, Filipe; Casiraghi, Maurizio; de Almeida, Izabela N.F.; de Almeida, Luciana N.F.; Nascimento dos Santos, Jeannie; Furtado, Adriano Penha; Sobrinho, Edmundo F. de Almeida; Bain, Odile

    2011-01-01

    A case of human intraocular dirofilariasis is reported from northern Brazil. The nematode was morphologically and phylogenetically related to Dirofilaria immitis but distinct from reference sequences, including those of D. immitis infesting dogs in the same area. A zoonotic Dirofilaria species infesting wild mammals in Brazil and its implications are discussed. PMID:21529396

  1. Evolutionary history of nematodes associated with sweat bees.

    Science.gov (United States)

    McFrederick, Quinn S; Taylor, Douglas R

    2013-03-01

    Organisms that live in close association with other organisms make up a large part of the world's diversity. One driver of this diversity is the evolution of host-species specificity, which can occur via reproductive isolation following a host-switch or, given the correct circumstances, via cospeciation. In this study, we explored the diversity and evolutionary history of Acrostichus nematodes that are associated with halictid bees in North America. First, we conducted surveys of bees in Virginia, and found six halictid species that host Acrostichus. To test the hypothesis of cospeciation, we constructed phylogenetic hypotheses of Acrostichus based on three genes. We found Acrostichus puri and Acrostichus halicti to be species complexes comprising cryptic, host-specific species. Although several nodes in the host and symbiont phylogenies were congruent and tests for cospeciation were significant, the host's biogeography, the apparent patchiness of the association across the host's phylogeny, and the amount of evolution in the nematode sequence suggested a mixture of cospeciation, host switching, and extinction events instead of strict cospeciation. Cospeciation can explain the relationships between Ac. puri and its augochlorine hosts, but colonization of Halictus hosts is more likely than cospeciation. The nematodes are vertically transmitted, but sexual transmission is also likely. Both of these transmission modes may explain host-species specificity and congruent bee and nematode phylogenies. Additionally, all halictid hosts come from eusocial or socially polymorphic lineages, suggesting that sociality may be a factor in the suitability of hosts for Acrostichus. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Genetic diversity of the potato cyst nematode in the Netherlands

    NARCIS (Netherlands)

    Folkertsma, R.T.

    1997-01-01


    The potato cyst nematodes Globodera rostochiensis (Woll.) Skarbilovich and G. pallida (Stone) originate from the Andes region in South America and have been introduced into Western Europe since 1850. Both species are

  3. Endogenous cellulases in stylet secretions of cyst nematodes

    NARCIS (Netherlands)

    Smant, G.

    1998-01-01

    This thesis describes the identification ofβ-1,4-endoglucanases (cellulases) in stylet secretions of the two cyst nematodes species, Globodera rostochiensis and Heterodera glycines . A novel method was developed to raise monoclonal antibodies that were

  4. Limiting opportunities for cheating stabilizes virulence in insect parasitic nematodes.

    Science.gov (United States)

    Shapiro-Ilan, David; Raymond, Ben

    2016-03-01

    Cooperative secretion of virulence factors by pathogens can lead to social conflict when cheating mutants exploit collective secretion, but do not contribute to it. If cheats outcompete cooperators within hosts, this can cause loss of virulence. Insect parasitic nematodes are important biocontrol tools that secrete a range of significant virulence factors. Critically, effective nematodes are hard to maintain without live passage, which can lead to virulence attenuation. Using experimental evolution, we tested whether social cheating might explain unstable virulence in the nematode Heterorhabditis floridensis by manipulating relatedness via multiplicity of infection (MOI), and the scale of competition. Passage at high MOI, which should reduce relatedness, led to loss of fitness: virulence and reproductive rate declined together and all eight independent lines suffered premature extinction. As theory predicts, relatedness treatments had more impact under stronger global competition. In contrast, low MOI passage led to more stable virulence and increased reproduction. Moreover, low MOI lineages showed a trade-off between virulence and reproduction, particularly for lines under stronger between-host competition. Overall, this study indicates that evolution of virulence theory is valuable for the culture of biocontrol agents: effective nematodes can be improved and maintained if passage methods mitigate possible social conflicts.

  5. Farmer evaluation of biocontrol methods against rootknot nematodes in tomatoes

    OpenAIRE

    McLeod, Anni; Ndungu, Beth; Karanja, Daniel; Karanja, Peter

    2002-01-01

    This report was presented at the UK Organic Research 2002 Conference. Root-knot nematodes in tomatoes cause financial loss to Kenyan smallholders. While soil fumigation appears to be losing effectiveness two bio-control agents (bcas), Pasteuria penetrans and Verticillium chlamydosporium, appear promising. Participatory budgeting is being used to compare the bcas with chemical and other biological controls on commercial and organic smallholdings.

  6. Mechanisms Involved in Nematode Control by Endophytic Fungi

    NARCIS (Netherlands)

    Schouten, Sander

    2016-01-01

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood

  7. Parasitic nematodes in the chimpanzee population on Rubondo Island, Tanzania

    Czech Academy of Sciences Publication Activity Database

    Petrželková, Klára Judita; Hasegawa, H.; Moscovice, L. R.; Kaur, T.; Issa, M. H.; Huffman, M. A.

    2006-01-01

    Roč. 27, č. 3 (2006), s. 767-777 ISSN 0164-0291 Institutional research plan: CEZ:AV0Z60930519 Keywords : chimpanzee * introduced population * nematode * new parasite record * Rubondo Island Subject RIV: EG - Zoology Impact factor: 1.331, year: 2006

  8. Nematodes inhabit soils of forest and clear-cut areas

    Science.gov (United States)

    Alex L. Shigo; George Yelenosky

    1960-01-01

    Nematodes are present in all forest soils, but their effects on forest trees are not known. The known destructive nature of these worms on other woody crops suggests that they may also be involved in causing some of the unexplainable losses in vigor and mortality of forest trees.

  9. Nematodes for the biological control of the woodwasp, Sirex noctilio

    Science.gov (United States)

    Robin A. Bedding

    2007-01-01

    The tylenchid nematode Beddingia (Deladenus) siricidicola (Bedding) is by far the most important control agent of Sirex noctilio F., a major pest of pine plantations. It sterilizes female sirex, is density dependent, can achieve nearly 100 percent parasitism and, as a result of its complicated biology can be readily manipulated for sirex control. Bedding and Iede (2005...

  10. Effect of entomopathogenic nematodes on Plectrodera scalator (Fabricius) (Coleoptera: Cerambycidae)

    Science.gov (United States)

    Declan J. Fallon; Leellen F. Solter; Leah S. Bauer; Deborah L. Miller; James R. Cate; Michael L. McManus

    2006-01-01

    Entomopathogenic nematodes were screened for efficacy against the cottonwood borer, Plectrodera scalator (Fabricius). Steinernema feltiae SN and S. carpocapsae All killed 58 and 50% of larvae, respectively, in Wlter paper bioassays but less than 10% in diet cup bioassays. S. glaseri NJ, S. riobrave TX, and H. indica MG-13 killed less than 10% of larvae in both assays....

  11. Radiation Effects on Nematodes: Results from IML-1 Esperiments

    Science.gov (United States)

    Nelson, G. A.; Schubert, W. W.; Kazarians, G. A.; Righards, G. F.; Benton, E. V; Benton, E. R.; Henke, R.

    1993-01-01

    The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA Biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plactic nuclear track detectors to correlate fluence of HZE particles with genetic events.

  12. Anthelmintic effects of forage chicory against parasitic nematodes in cattle

    DEFF Research Database (Denmark)

    Pena-Espinoza, Miguel Angel; Williams, Andrew; Thamsborg, Stig Milan

    BACKGROUND: Chicory (Cichorium intybus) has potential as a natural anthelmintic in livestock, however evidence of efficacy against cattle nematodes is lacking. Here, we investigated anthelmintic effects of chicory in stabled calves. METHODS: Jersey male calves (2-4 months) were stratified by live...

  13. Pyramiding, alternating or mixing: comparative performances of deployment strategies of nematode resistance genes to promote plant resistance efficiency and durability.

    Science.gov (United States)

    Djian-Caporalino, Caroline; Palloix, Alain; Fazari, Ariane; Marteu, Nathalie; Barbary, Arnaud; Abad, Pierre; Sage-Palloix, Anne-Marie; Mateille, Thierry; Risso, Sabine; Lanza, Roger; Taussig, Catherine; Castagnone-Sereno, Philippe

    2014-02-22

    Resistant cultivars are key elements for pathogen control and pesticide reduction, but their repeated use may lead to the emergence of virulent pathogen populations, able to overcome the resistance. Increased research efforts, mainly based on theoretical studies, explore spatio-temporal deployment strategies of resistance genes in order to maximize their durability. We evaluated experimentally three of these strategies to control root-knot nematodes: cultivar mixtures, alternating and pyramiding resistance genes, under controlled and field conditions over a 3-years period, assessing the efficiency and the durability of resistance in a protected crop rotation system with pepper as summer crop and lettuce as winter crop. The choice of the resistance gene and the genetic background in which it is introgressed, affected the frequency of resistance breakdown. The pyramiding of two different resistance genes in one genotype suppressed the emergence of virulent isolates. Alternating different resistance genes in rotation was also efficient to decrease virulent populations in fields due to the specificity of the virulence and the trapping effect of resistant plants. Mixing resistant cultivars together appeared as a less efficient strategy to control nematodes. This work provides experimental evidence that, in a cropping system with seasonal sequences of vegetable species, pyramiding or alternating resistance genes benefit yields in the long-term by increasing the durability of resistant cultivars and improving the long-term control of a soil-borne pest. To our knowledge, this result is the first one obtained for a plant-nematode interaction, which helps demonstrate the general applicability of such strategies for breeding and sustainable management of resistant cultivars against pathogens.

  14. Characterizing Ancylostoma caninum transcriptome and exploring nematode parasitic adaptation

    Directory of Open Access Journals (Sweden)

    Hawdon John

    2010-05-01

    Full Text Available Abstract Background Hookworm infection is one of the most important neglected diseases in developing countries, with approximately 1 billion people infected worldwide. To better understand hookworm biology and nematode parasitism, the present study generated a near complete transcriptome of the canine hookworm Ancylostoma caninum to a very high coverage using high throughput technology, and compared it to those of the free-living nematode Caenorhabditis elegans and the parasite Brugia malayi. Results The generated transcripts from four developmental stages, infective L3, serum stimulated L3, adult male and adult female, covered 93% of the A. caninum transcriptome. The broad diversity among nematode transcriptomes was confirmed, and an impact of parasitic adaptation on transcriptome diversity was inferred. Intra-population analysis showed that A. caninum has higher coding sequence diversity than humans. Examining the developmental expression profiles of A. caninum revealed major transitions in gene expression from larval stages to adult. Adult males expressed the highest number of selectively expressed genes, but adult female expressed the highest number of selective parasitism-related genes. Genes related to parasitism adaptation and A. caninum specific genes exhibited more expression selectivity while those conserved in nematodes tend to be consistently expressed. Parasitism related genes were expressed more selectively in adult male and female worms. The comprehensive analysis of digital expression profiles along with transcriptome comparisons enabled identification of a set of parasitism genes encoding secretory proteins in animal parasitic nematode. Conclusions This study validated the usage of deep sequencing for gene expression profiling. Parasitic adaptation of the canine hookworm is related to its diversity and developmental dynamics. This comprehensive comparative genomic and expression study substantially improves our understanding of

  15. Practical application of insect-parasitic nematodes and sterile flies

    International Nuclear Information System (INIS)

    Galle, F.; Loosjes, M.

    1987-01-01

    The company 'de Groene Vlieg' started with commercial control of the onion fly by means of the sterile insect technique. At the moment 10 per cent of the Dutch spring sown onions are treated with this method. The mass-rearing, the estimations of populations and the repeated releases of sterilized flies make it a rather complicated method. It can be applied economically per field, but only in areas with a concentration of onion growing. For export we see no possibilities yet. In principle the sterile insect technique can be applied also to other flies (carrot rust fly, cabbage root fly), but a suitable artificial diet is still lacking. Since some years we also rear the insect parasitic nematodes Heterorhabditis sp. and Neoaplectana bibionis. The later is experimentally used with success against Agrotis segetum caterpillars in lettuce. Research will yield more applications of nematodes against different pests. We use Heterorhabditis sp. in practice against the black vine weevil (Otiorhynchus sulcatus), a serious pest in glass houses, tree nurseries and gardens. Good control is achieved with a dose of one half to one million nematodes per square meter in moist soil and with temperatures above 12 degrees C. The application is similar to that of a chemical insecticide. The pest is killed by symbiontic bacteria, released by the nematodes after penetrating into the body cavity of the larvae. The nematodes are delivered by mail. If cooled they can be kept alive for over four weeks in the package. We export already to Switzerland and plan to export also to Western Germany. At this moment a possible admittance is under investigation in the Netherlands for application of a nuclear polyhedrosis virus against Spodoptera exigua caterpillars

  16. SPRYSEC effectors: a versatile protein-binding platform to disrupt plant innate immunity

    Directory of Open Access Journals (Sweden)

    Amalia Diaz-Granados

    2016-10-01

    Full Text Available Persistent infections by sedentary plant-parasitic nematodes are a major threat to important food crops all over the world. These round worms manipulate host plant cell morphology and physiology to establish sophisticated feeding structures. Key modifications to plant cells during their transition into feeding structures are largely attributed to the activity of effectors secreted by the nematodes. The SPRYSEC effectors were initially identified in the potato cyst nematodes Globodera rostochiensis and G. pallida, and are characterized by a single SPRY domain, a non-catalytic domain present in modular proteins with different functions. The SPRY domain is wide-spread among eukaryotes and thought to be involved in mediating protein-protein interactions. Thus far, the SPRY domain is only reported as a functional domain in effectors of plant-parasitic nematodes, but not of other plant pathogens. SPRYSEC effectors have been implicated in both suppression and activation of plant immunity, but other possible roles in nematode virulence remain undefined. Here, we review the latest reports on the structure, function, and sequence diversity of SPRYSEC effectors, which provide support for a model featuring these effectors as a versatile protein-binding platform for the nematodes to target a wide range of host proteins during parasitism.

  17. Synthetic Ligands of Cannabinoid Receptors Affect Dauer Formation in the Nematode Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Pedro Reis Rodrigues

    2016-06-01

    Full Text Available Under adverse environmental conditions the nematode Caenorhabditis elegans can enter an alternate developmental stage called the dauer larva. To identify lipophilic signaling molecules that influence this process, we screened a library of bioactive lipids and found that AM251, an antagonist of the human cannabinoid (CB receptor, suppresses dauer entry in daf-2 insulin receptor mutants. AM251 acted synergistically with glucose supplementation indicating that the metabolic status of the animal influenced the activity of this compound. Similarly, loss of function mutations in the energy-sensing AMP-activated kinase subunit, aak-2, enhanced the dauer-suppressing effects of AM251, while constitutive activation of aak-2 in neurons was sufficient to inhibit AM251 activity. Chemical epistasis experiments indicated that AM251 acts via G-protein signaling and requires the TGF-β ligand DAF-7, the insulin peptides DAF-28 and INS-6, and a functional ASI neuron to promote reproductive growth. AM251 also required the presence of the SER-5 serotonin receptor, but in vitro experiments suggest that this may not be via a direct interaction. Interestingly, we found that other antagonists of mammalian CB receptors also suppress dauer entry, while the nonselective CB receptor agonist, O-2545, not only inhibited the activity of AM251, but also was able to promote dauer entry when administered alone. Since worms do not have obvious orthologs of CB receptors, the effects of synthetic CBs on neuroendocrine signaling in C. elegans are likely to be mediated via another, as yet unknown, receptor mechanism. However, we cannot exclude the existence of a noncanonical CB receptor in C. elegans.

  18. Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes

    NARCIS (Netherlands)

    Shah, Syed Jehangir; Anjam, Muhammad Shahzad; Mendy, Badou; Anwer, Muhammad Arslan; Habash, Samer S.; Lozano-Torres, Jose L.; Grundler, Florian M.W.; Siddique, Shahid

    2017-01-01

    When nematodes invade and subsequently migrate within plant roots, they generate cell wall fragments (in the form of oligogalacturonides; OGs) that can act as damage-associated molecular patterns and activate host defence responses. However, the molecular mechanisms mediating damage responses in

  19. The effector SPRYSEC-19 of Globodera rostochiensis suppresses CC-NB-LRR-mediated disease resistance in plants.

    Science.gov (United States)

    Postma, Wiebe J; Slootweg, Erik J; Rehman, Sajid; Finkers-Tomczak, Anna; Tytgat, Tom O G; van Gelderen, Kasper; Lozano-Torres, Jose L; Roosien, Jan; Pomp, Rikus; van Schaik, Casper; Bakker, Jaap; Goverse, Aska; Smant, Geert

    2012-10-01

    The potato cyst nematode Globodera rostochiensis invades roots of host plants where it transforms cells near the vascular cylinder into a permanent feeding site. The host cell modifications are most likely induced by a complex mixture of proteins in the stylet secretions of the nematodes. Resistance to nematodes conferred by nucleotide-binding-leucine-rich repeat (NB-LRR) proteins usually results in a programmed cell death in and around the feeding site, and is most likely triggered by the recognition of effectors in stylet secretions. However, the actual role of these secretions in the activation and suppression of effector-triggered immunity is largely unknown. Here we demonstrate that the effector SPRYSEC-19 of G. rostochiensis physically associates in planta with the LRR domain of a member of the SW5 resistance gene cluster in tomato (Lycopersicon esculentum). Unexpectedly, this interaction did not trigger defense-related programmed cell death and resistance to G. rostochiensis. By contrast, agroinfiltration assays showed that the coexpression of SPRYSEC-19 in leaves of Nicotiana benthamiana suppresses programmed cell death mediated by several coiled-coil (CC)-NB-LRR immune receptors. Furthermore, SPRYSEC-19 abrogated resistance to Potato virus X mediated by the CC-NB-LRR resistance protein Rx1, and resistance to Verticillium dahliae mediated by an unidentified resistance in potato (Solanum tuberosum). The suppression of cell death and disease resistance did not require a physical association of SPRYSEC-19 and the LRR domains of the CC-NB-LRR resistance proteins. Altogether, our data demonstrated that potato cyst nematodes secrete effectors that enable the suppression of programmed cell death and disease resistance mediated by several CC-NB-LRR proteins in plants.

  20. Soil properties influencing phytoparasitic nematode population on Chilean vineyards Propiedades del suelo que influyen en la población de nematodos fitoparásitos en viñedos de Chile

    Directory of Open Access Journals (Sweden)

    Mario Fajardo P

    2011-06-01

    Full Text Available Lifecycle of phytoparasitic nematode takes place in the rhizosphere, therefore their breeding, parasitism and mobility dynamics are inevitably influenced by the soil-root interaction, A study was performed to evaluate the influence of Vitis rootstocks to some plant parasitic nematodes under different soil conditions. Nematode populations were assessed in Vitis vinifera L. var ‘Chardonnay’ plants grafted on two rootstocks (K5BB, SO4 and ungrafted ‘Chardonnay’ as a control in three diferent alluvial soils in the central zone of Chile. Soils were two Inceptisols of the Casablanca Valley (Valparaíso Region, the first one without soil structure and with a densification zone in depth (S1 and the second one with sandy textural class (S3. A third soil was a Mollisol (S2 more structured than the others, situated on a locality of Melipilla (Metropolitan Region. The soils were characterized physically and morphologically and nematode genera were identified and counted using a dissecting microscope. ‘Chardonnay’ presented the highest population of Meloidogyne spp. on the three soil conditions but only significant in S2 soil. The population of Xiphinema spp. and Mesocriconema xenoplax were not representative enough to relate them with either soil or the different rootstocks. The amount of Meloidogyne spp. was inversely related with the sand content but positively related with the more structured soil. The stepwise regressions resulted useful when relating nematode populations with multiple soil factors.El ciclo de vida de los nematodos fitoparásitos ocurre en la rizósfera, por lo tanto, sus dinámicas de alimentación, parasitismo y movilidad están inevitablemente influenciadas por la interacción suelo-raíz. Se llevó a cabo un estudio para evaluar la respuesta de diferentes portainjertos de Vitis frente a algunas poblaciones de nematodos fitoparásitos en diferentes tipos de suelos. Se determinaron las poblaciones de nematodos fitopar