scholarly journals RNA Interference of Dual Oxidase in the Plant Nematode Meloidogyne incognita

2005 ◽  
Vol 18 (10) ◽  
pp. 1099-1106 ◽  
Author(s):  
Manjula Bakhetia ◽  
Wayne Charlton ◽  
Howard J. Atkinson ◽  
Michael J. McPherson
Keyword(s):  
Rna Interference ◽  
Gene Function ◽  
Meloidogyne Incognita ◽  
Feeding Strategy ◽  
Model Organisms ◽  
Parasitic Nematodes ◽  
In Planta ◽  
Oxidase Gene ◽  
Dual Oxidase

RNA interference (RNAi) is a powerful tool for the analysis of gene function in model organisms such as the nematode Caenorhabditis elegans. Recent demonstrations of RNAi in plant parasitic nematodes provide a stimulus to explore the potential of using RNAi to investigate disruption of gene function in Meloidogyne incognita, one of the most important nematode pests of global agriculture. We have used RNAi to examine the importance of dual oxidases (peroxidase and NADPH oxidase), a class of enzyme associated with extracellular matrix cross-linking in C. elegans. RNAi uptake by M. incognita juveniles is highly efficient. In planta infection data show that a single 4-h preinfection treatment with double-stranded RNA derived from the peroxidase region of a dual oxidase gene has effects on gene expression that are phenotypically observable 35 days postinfection. This RNAi effect results in a reduction in egg numbers at 35 days of up to 70%. The in vitro feeding strategy provides a powerful tool for identifying functionally important genes, including those that are potential targets for the development of new agrochemicals or transgenic resistance strategies.

The Use of RNA Interference in Enhancing Plant Resistance against Nematodes

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Siye Chen
Keyword(s):  
Rna Interference ◽  
Plant Resistance ◽  
Parasitic Nematodes ◽  
Great Success ◽  
Plant Parasitic Nematodes ◽  
In Planta ◽  
Rnai Technology ◽  
Wide Range ◽  
Plant Parasitic

Plant-parasitic nematodes caused severe yield loss in major crops all over the world. The most wild-used strategies to combat the nematodes is the chamical nematicides, but the overuse of synthetic nematicides threaten sustainable agriculture development. Other strategies, like resistance cultivars and crop rotation, have limited efficiency. Thus, the utilization of molecular biotechnology like RNA interference (RNAi) would be one of the alternative ways to enhance plant resistance against nematodes. RNAi has already used as a tool for gene functional analysis in a wide range of species, especially in the non-parasitic nematode, Caenorhabtidis elegans. In plant-parasitic nematodes, RNAi is induced by soaking nematodes with double-strand RNA(dsRNA) solution mixed with neurostimulants, which is called in vitro RNAi delivery method. In another way around, in planta RNAi method, which is Host-mediated RNAi approach also showed a great success in conferring the resistance against root-knock nematodes. Two main advantages of RNAi-based transgenics are RNAi technology do not produce any functional foreign proteins and it target organisms in a sequence-specific way. Even though the development of RNAi-based transgenics against plant-parasitic nematodes is still in the initial phase, it offers the prospect into a novel nematode control strategy in the future.

Getting to the root of neuronal signalling in plant-parasitic nematodes using RNA interference

Nematology ◽  
2007 ◽  
Vol 9 (3) ◽  
pp. 301-315 ◽  
Author(s):  
Steven McMaster ◽  
Susan McKinney ◽  
Aaron Maule ◽  
Michael Kimber ◽  
Colin Fleming ◽  
...  
Keyword(s):  
Rna Interference ◽  
Control Strategies ◽  
Large Family ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
In Planta ◽  
Nematode Parasites ◽  
Neuronal Signalling ◽  
Plant Parasitic

AbstractA variety of genes expressed in preparasitic second-stage juveniles (J2) of plant-parasitic nematodes appear to be vulnerable to RNA interference (RNAi) in vitro by coupling double-stranded (ds)RNA soaking with the artificial stimulation of pharyngeal pumping. Also, there is mounting evidence that the in planta generation of nematode-specific double-stranded RNAs (dsRNAs) has real utility in the control of these pests. Although neuronally-expressed genes in Caenorhabditis elegans are commonly refractory to RNAi, we have discovered that neuronally-expressed genes in plant-parasitic nematodes are highly susceptible to RNAi and that silencing can be induced by simple soaking procedures without the need for pharyngeal stimulation. Since most front-line anthelmintics that are used for the control of nematode parasites of animals and humans act to disrupt neuromuscular coordination, we argue that intercellular signalling processes associated with neurons have much appeal as targets for transgenic plant-based control strategies for plant-parasitic nematodes. FMRFamide-like peptides (FLPs) are a large family of neuropeptides which are intimately associated with neuromuscular regulation, and our studies on flp gene function in plant-parasitic nematodes have revealed that their expression is central to coordinated locomotory activities. We propose that the high level of conservation in nervous systems across nematodes coupled with the RNAi-susceptibility of neuronally-expressed genes in plant-parasitic nematodes provides a valuable research tool which could be used to interrogate neuronal signalling processes in nematodes.

Combinatorial in vitro RNAi of two neuropeptide genes and a pharyngeal gland gene on Meloidogyne incognita

Nematology ◽  
2015 ◽  
Vol 17 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Prakash Banakar ◽  
Amita Sharma ◽  
Catherine J. Lilley ◽  
Nagavara Prasad Gantasala ◽  
Mukesh Kumar ◽  
...  
Keyword(s):  
Meloidogyne Incognita ◽  
Parasitic Nematodes ◽  
Specific Gene ◽  
Plant Parasitic Nematodes ◽  
Rnai Silencing ◽  
Transcript Quantification ◽  
The Central Nervous System ◽  
Pharyngeal Gland

Root-knot nematodes are the most economically important group of plant-parasitic nematodes. In the present study, functional validation using in vitro RNAi was carried out on Meloidogyne incognita with two FMRFamide-like peptide genes, flp-14 and flp-18, and a subventral pharyngeal gland specific gene, 16D10. It was found that RNAi silencing of each gene reduced the attraction of M. incognita at different time intervals both in combination and individually. Silencing of the genes reduced nematode infection by 23-30% and development as indicated by a reduction in the number of females by 26-62%. Reproduction was decreased by 27-73% and fecundity was decreased by 19-51%. In situ hybridisation revealed the expression of flp-18 in cells associated with the ventral and retro vesicular ganglia of the central nervous system. qRT-PCR supported the correlation between phenotypic effects of silencing with that of transcript quantification.

scholarly journals Activity of Saponins from Medicago Species against Phytoparasitic Nematodes

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 443 ◽  
Author(s):  
Trifone D’Addabbo ◽  
Maria Pia Argentieri ◽  
Jerzy Żuchowski ◽  
Elisa Biazzi ◽  
Aldo Tava ◽  
...  
Keyword(s):  
Meloidogyne Incognita ◽  
In Vitro Assays ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Phytoparasitic Nematodes ◽  
Phytochemical Profile ◽  
Medicago Species ◽  
Phytoparasitic Nematode ◽  
Plant Parasitic

Content of bioactive saponins of Medicago species suggests that they may also exert, as previously demonstrated on M. sativa, nematicidal properties exploitable for the formulation of new products for sustainable phytoparasitic nematode management. This study was addressed to highlight the bioactivity of saponins from five different Medicago species still poorly known for their biological efficacy, i.e., M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, against the plant parasitic nematodes Meloidogyne incognita, Xiphinema index and Globodera rostochiensis. The bioactivity of the extracts from the five Medicago species was assessed by in vitro assays on the juveniles (J2) and eggs of M. incognita and G. rostochiensis and the adult females of X. index. The suppressiveness to M. incognita of soil treatments with the Medicago plant biomasses was also investigated in a tomato experiment. The nematicidal activity of the five Medicago species was reported and discussed in relation to their phytochemical profile.

Considering RNAi experimental design in parasitic helminths

Parasitology ◽  
2012 ◽  
Vol 139 (5) ◽  
pp. 589-604 ◽  
Author(s):  
JOHNATHAN J. DALZELL ◽  
NEIL D. WARNOCK ◽  
PAUL MCVEIGH ◽  
NIKKI J. MARKS ◽  
ANGELA MOUSLEY ◽  
...  
Keyword(s):  
Rna Interference ◽  
Experimental Design ◽  
Gene Function ◽  
Experimental Validation ◽  
Parasite Species ◽  
Model Organisms ◽  
Helminth Parasites ◽  
Parasitic Helminth ◽  
Parasitic Helminths ◽  
Parasite Biology

SUMMARYAlmost a decade has passed since the first report of RNA interference (RNAi) in a parasitic helminth. Whilst much progress has been made with RNAi informing gene function studies in disparate nematode and flatworm parasites, substantial and seemingly prohibitive difficulties have been encountered in some species, hindering progress. An appraisal of current practices, trends and ideals of RNAi experimental design in parasitic helminths is both timely and necessary for a number of reasons: firstly, the increasing availability of parasitic helminth genome/transcriptome resources means there is a growing need for gene function tools such as RNAi; secondly, fundamental differences and unique challenges exist for parasite species which do not apply to model organisms; thirdly, the inherent variation in experimental design, and reported difficulties with reproducibility undermine confidence. Ideally, RNAi studies of gene function should adopt standardised experimental design to aid reproducibility, interpretation and comparative analyses. Although the huge variations in parasite biology and experimental endpoints make RNAi experimental design standardization difficult or impractical, we must strive to validate RNAi experimentation in helminth parasites. To aid this process we identify multiple approaches to RNAi experimental validation and highlight those which we deem to be critical for gene function studies in helminth parasites.

scholarly journals Antisense RNA Modulation of Alkyl Hydroperoxide Reductase Levels in Helicobacter pylori Correlates with Organic Peroxide Toxicity but Not Infectivity

2007 ◽  
Vol 189 (9) ◽  
pp. 3359-3368 ◽  
Author(s):  
Matthew A. Croxen ◽  
Peter B. Ernst ◽  
Paul S. Hoffman
Keyword(s):  
Helicobacter Pylori ◽  
Rna Interference ◽  
Gene Function ◽  
Antisense Rna ◽  
In Vitro Growth ◽  
Protein Levels ◽  
Alkyl Hydroperoxide ◽  
Gastric Colonization ◽  
H Pylori

ABSTRACT Much of the gene content of the human gastric pathogen Helicobacter pylori (∼1.7-Mb genome) is considered essential. This view is based on the completeness of metabolic pathways, infrequency of nutritional auxotrophies, and paucity of pathway redundancies typically found in bacteria with larger genomes. Thus, genetic analysis of gene function is often hampered by lethality. In the absence of controllable promoters, often used to titrate gene function, we investigated the feasibility of an antisense RNA interference strategy. To test the antisense approach, we targeted alkyl hydroperoxide reductase (AhpC), one of the most abundant proteins expressed by H. pylori and one whose function is essential for both in vitro growth and gastric colonization. Here, we show that antisense ahpC (as-ahpC) RNA expression from shuttle vector pDH37::as-ahpC achieved an ∼72% knockdown of AhpC protein levels, which correlated with increased susceptibilities to hydrogen peroxide, cumene, and tert-butyl hydroperoxides but not with growth efficiency. Compensatory increases in catalase levels were not observed in the knockdowns. Expression of single-copy antisense constructs (expressed under the urease promoter and containing an fd phage terminator) from the rdxA locus of mouse-colonizing strain X47 achieved a 32% knockdown of AhpC protein levels (relative to wild-type X47 levels), which correlated with increased susceptibility to organic peroxides but not with mouse colonization efficiency. Our studies indicate that high levels of AhpC are not required for in vitro growth or for primary gastric colonization. Perhaps AhpC, like catalase, assumes a greater role in combating exogenous peroxides arising from lifelong chronic inflammation. These studies also demonstrate the utility of antisense RNA interference in the evaluation of gene function in H. pylori.

Toxicity of ethanol solutions and vapours against Meloidogyne incognita

Nematology ◽  
2017 ◽  
Vol 19 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Julio C.P. Silva ◽  
Vicente P. Campos ◽  
Eduardo S. Freire ◽  
Willian C. Terra ◽  
Liliana E. Lopez
Keyword(s):  
Root System ◽  
Meloidogyne Incognita ◽  
Parasitic Nematodes ◽  
Infested Soil ◽  
Large Reduction ◽  
Plant Parasitic Nematodes ◽  
Second Stage ◽  
Plant Parasitic

Ethanol (EtOH) is less harmful to humans than currently available nematicide molecules. This study evaluated the efficacy of EtOH in controlling Meloidogyne incognita in vitro and in lettuce plants under glasshouse conditions. Aqueous EtOH solutions (5-70% volume) and their vapours caused an acute nematicidal effect in vitro in second-stage juveniles (J2) of M. incognita and reduced hatching of J2. There was a large reduction of galls and eggs in the root system when 40 ml of EtOH was applied to M. incognita-infested soil at concentrations of 40 and 70%. Water exposed to EtOH vapours for 1 h became toxic, and a 12-h exposure caused 100% J2 mortality. Use of a plastic cover did not increase the efficiency of EtOH in controlling M. incognita in lettuce plants. The observed EtOH effects indicate its prospective use in controlling plant-parasitic nematodes, especially in glasshouses.

Responses of Heterodera glycines and Meloidogyne incognita to exogenously applied biogenic amines

Nematology ◽  
2008 ◽  
Vol 10 (6) ◽  
pp. 911-917 ◽  
Author(s):  
Edward Masler
Keyword(s):  
Biogenic Amines ◽  
Meloidogyne Incognita ◽  
Head Movement ◽  
Heterodera Glycines ◽  
Parasitic Nematodes ◽  
Stage Juvenile ◽  
Quantitative Analyses ◽  
Effective Doses ◽  
Plant Parasitic

AbstractHatching and head movement behaviours of second-stage juvenile (J2) of two agriculturally important plant-parasitic nematodes were affected by the in vitro application of biogenic amines. The behavioural responses of Heterodera glycines and Meloidogyne incognita to treatments of serotonin, octopamine and dopamine were qualitatively similar, but significant quantitative differences between the species were revealed. The frequency of J2 head movement was decreased by as little as 250 μM serotonin in H. glycines and 500 μM serotonin in M. incognita, with effective doses (ED50) of 0.73 mM for H. glycines and 1.72 mM for M. incognita. Octopamine had the opposite effect of serotonin, increasing J2 head movement frequency at thresholds of 2 mM in H. glycines and 1 mM in M. incognita. Octopamine ED50 values were 32.35 mM and 1.91 mM, respectively. Dopamine had no effect on head movement in either species up to concentrations of 20 mM. Serotonin inhibited hatch in both species but was more potent against H. glycines (90% inhibition at 1 mM) than M. incognita (40% inhibition at 5 mM). Octopamine reduced hatch equally in both species with over 95% inhibition at 80 mM. Dopamine had no effect on hatch in M. incognita but did inhibit H. glycines hatch over 60% at 40 mM. The value of detailed quantitative analyses of plant-parasitic nematode responses to biogenic amines for studies on nematode control is discussed.

scholarly journals Chromatin landscape dynamics in development of the plant parasitic nematode Meloidogyne incognita

2021 ◽  
Author(s):  
Rahim Hassanaly-Goulamhoussen ◽  
Ronaldo De Carvalho Augusto ◽  
Nathalie Marteu-Garello ◽  
Arthur Péré ◽  
Bruno Favery ◽  
...  
Keyword(s):  
Gene Expression ◽  
Histone Modifications ◽  
Meloidogyne Incognita ◽  
Developmental Stages ◽  
Model Organisms ◽  
Parasitic Nematodes ◽  
Epigenetic Mechanisms ◽  
Root Knot Nematode ◽  
Dynamic Regulation ◽  
Plant Parasitic

In model organisms, epigenome dynamics underlies a plethora of biological processes. The role of epigenetic modifications in development and parasitism in nematode pests remains unknown. The root-knot nematode Meloidogyne incognita adapts rapidly to unfavorable conditions, despite its asexual reproduction. However, the mechanisms underlying this remarkable plasticity and their potential impact on gene expression remain unknown. This study provides the first insight into contribution of epigenetic mechanisms to this plasticity, by studying histone modifications in M. incognita. The distribution of five histone modifications revealed the existence of strong epigenetic signatures, similar to those found in the model nematode Caenorhabditis elegans. We investigated their impact on chromatin structure and their distribution relative to transposable elements (TE) loci. We assessed the influence of the chromatin landscape on gene expression at two developmental stages: eggs, and pre-parasitic juveniles. H3K4me3 histone modification was strongly correlated with high levels of expression for protein-coding genes implicated in stage-specific processes during M. incognita development. We provided new insights in the dynamic regulation of parasitism genes kept under histone modifications silencing. In this pioneering study, we establish a comprehensive framework for the importance of epigenetic mechanisms in the regulation of the genome expression and its stability in plant-parasitic nematodes.

RNA interference in parasitic helminths: current situation, potential pitfalls and future prospects

Parasitology ◽  
2006 ◽  
Vol 134 (5) ◽  
pp. 609-619 ◽  
Author(s):  
P. GELDHOF ◽  
A. VISSER ◽  
D. CLARK ◽  
G. SAUNDERS ◽  
C. BRITTON ◽  
...  
Keyword(s):  
Rna Interference ◽  
Culture Conditions ◽  
Gene Knockdown ◽  
Future Application ◽  
Parasitic Nematodes ◽  
Parasitic Helminths ◽  
Rnai Treatment ◽  
Free Living Nematode ◽  
Invaluable Tool

SUMMARYRNA interference (RNAi) has become an invaluable tool for the functional analysis of genes in a wide variety of organisms including the free-living nematode Caenorhabditis elegans. Recently, attempts have been made to apply this technology to parasitic helminths of animals and plants with variable success. Gene knockdown has been reported for Schistosoma mansoni by soaking or electroporating different life-stages in dsRNA. Similar approaches have been tested on parasitic nematodes which clearly showed that, under certain conditions, it was possible to interfere with gene expression. However, despite these successes, the current utility of this technology in parasite research is questionable. First, problems have arisen with the specificity of RNAi. Treatment of the parasites with dsRNA resulted, in many cases, in non-specific effects. Second, the current RNAi methods have a limited efficiency and effects are sometimes difficult to reproduce. This was especially the case in strongylid parasites where only a small number of genes were susceptible to RNAi-mediated gene knockdown. The future application of RNAi in parasite functional genomics will greatly depend on how we can overcome these difficulties. Optimization of the dsRNA delivery methods and in vitro culture conditions will be the major challenges.

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