scholarly journals Ingestion of Double-Stranded RNA by Preparasitic Juvenile Cyst Nematodes Leads to RNA Interference

2002 ◽  
Vol 15 (8) ◽  
pp. 747-752 ◽  
Author(s):  
P. E. Urwin ◽  
Catherine J. Lilley ◽  
Howard J. Atkinson

RNA interference is of value in determining gene function in many organisms. Plant parasitic nematodes are refractory to microinjection as a means of introducing RNA and do not show any oral uptake until they are within plants. We have used octopamine to stimulate uptake by prepara-sitic second stage juveniles of two cyst nematodes, Heterodera glycines and Globodera pallida. This new technique was used to facilitate uptake of double stranded RNA (dsRNA) together with fluoroscein isothiocyanate as a visual marker. Targeting cysteine proteinases did not reduce the number of parasites but caused a shift from the normal female/male ratio of 3:1 to 1:1 by 14 days postinfection (dpi). Exposure of H. glycines to dsRNA corresponding to a newly characterized protein with homology to C-type lectins did not affect sexual fate, but 41% fewer parasites were recovered from the plants. As expected, treatment with dsRNA corresponding to the major sperm protein (MSP) had no effect on either parasite development or sexual fate over 14 days. Northern analysis showed lower transcript abundance for the two targeted mRNAs that occur in J2, plus a later inhibition for MSP transcripts when males developed sperm at 15 dpi. These findings establish a procedure for RNAi of plant parasitic nematodes.

2021 ◽  
pp. 408-413
Author(s):  
Shahid Siddique ◽  
Sebastian Eves-van den Akker

Abstract Plant parasitic nematodes are among the most destructive plant pathogens, causing an estimated US$78 billion yield losses globally. Although approximately 3000 species of plant parasitic nematodes have been described, most of the damage is caused by a small group of root-infecting sedentary endoparasitic nematodes that include root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.). Given that previous literature amply reviews the breadth of biotechnological methods for the control of plant parasitic nematodes, this chapter will briefly touch on long-standing biotechnological methods but focus on recent progress in, and long-term promise of, the use of CRISPR technology for introducing targeted modifications into host genomes with the goal of enhancing resistance against plant parasitic nematodes. It is predicted that expanding reverse genetic approaches beyond RNA interference, using low-cost, technically simple and efficient transformation (transient or stable) will be the single most important advance in the field in some years.


2005 ◽  
Vol 18 (7) ◽  
pp. 615-620 ◽  
Author(s):  
M.-N. Rosso ◽  
M. P. Dubrana ◽  
N. Cimbolini ◽  
S. Jaubert ◽  
P. Abad

Plant parasitic nematodes have been, so far, refractory to transformation or mutagenesis. The functional analysis of nematode genes relies on the development of reverse genetic tools adapted to these obligate parasites. Here, we describe the application of RNA interference (RNAi) to the root-knot nematode Meloidogyne incognita for the knock-down of two genes expressed in the subventral esophageal glands of the nematode and potentially involved in parasitism, the calreticulin (Mi-crt) and the polygalacturonase (Mi-pg-1) genes. Incubation in 1% resorcinol for 4 h induced double-stranded RNA uptake through the alimentary track of the nematodes and led to up to 92% depletion of Mi-crt transcripts. Timecourse analysis of the silencing showed different temporal patterns for Mi-crt and Mi-pg-1. The silencing of Mi-crt was optimal 20 h after soaking, whereas the silencing of Mi-pg-1 was optimal 44 h after soaking. For the two genes, the silencing effect was highly time-limited, since no transcript depletion was detectable 68 h after soaking.


2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Olaf Kranse ◽  
Helen Beasley ◽  
Sally Adams ◽  
Andre Pires-daSilva ◽  
Christopher Bell ◽  
...  

Abstract Plant-parasitic nematodes are a continuing threat to food security, causing an estimated 100 billion USD in crop losses each year. The most problematic are the obligate sedentary endoparasites (primarily root knot nematodes and cyst nematodes). Progress in understanding their biology is held back by a lack of tools for functional genetics: forward genetics is largely restricted to studies of natural variation in populations and reverse genetics is entirely reliant on RNA interference. There is an expectation that the development of functional genetic tools would accelerate the progress of research on plant-parasitic nematodes, and hence the development of novel control solutions. Here, we develop some of the foundational biology required to deliver a functional genetic tool kit in plant-parasitic nematodes. We characterize the gonads of male Heterodera schachtii and Meloidogyne hapla in the context of spermatogenesis. We test and optimize various methods for the delivery, expression, and/or detection of exogenous nucleic acids in plant-parasitic nematodes. We demonstrate that delivery of macromolecules to cyst and root knot nematode male germlines is difficult, but possible. Similarly, we demonstrate the delivery of oligonucleotides to root knot nematode gametes. Finally, we develop a transient expression system in plant-parasitic nematodes by demonstrating the delivery and expression of exogenous mRNA encoding various reporter genes throughout the body of H. schachtii juveniles using lipofectamine-based transfection. We anticipate these developments to be independently useful, will expedite the development of genetic modification tools for plant-parasitic nematodes, and ultimately catalyze research on a group of nematodes that threaten global food security.


Parasitology ◽  
2012 ◽  
Vol 140 (4) ◽  
pp. 445-454 ◽  
Author(s):  
JUAN E. PALOMARES-RIUS ◽  
JOHN T. JONES ◽  
PETER J. COCK ◽  
PABLO CASTILLO ◽  
VIVIAN C. BLOK

SUMMARYThe potato cyst nematodes (PCN) Globodera pallida and G. rostochiensis are major pests of potatoes. The G. pallida (and G. rostochiensis) life cycle includes both diapause and quiescent stages. Nematodes in dormancy (diapause or quiescent) are adapted for long-term survival and are more resistant to nematicides. This study analysed the mechanisms underlying diapause and quiescence. The effects of several compounds (8Br-cGMP, oxotremorine and atropine) on the activation of hatching were studied. The measurements of some morphometric parameters in diapaused and quiescent eggs after exposure to PRD revealed differences in dorsal gland length, subventral gland length and dorsal gland nucleolus. In addition, the expression of 2 effectors (IVg9 and cellulase) was not induced in diapaused eggs in water or PRD, while expression was slightly induced in quiescent eggs. Finally, we performed a comparative study to identify orthologues of C. elegans diapause related genes in plant-parasitic nematodes (G. pallida, Meloidogyne incognita, M. hapla and Bursaphelenchus xylophilus). This analysis suggested that it was not possible to identify G. pallida orthologues of the majority of C. elegans genes involved in the control of dauer formation. All these data suggest that G. pallida may use different mechanisms to C. elegans in regulating the survival stage.


Nematology ◽  
2012 ◽  
Vol 14 (7) ◽  
pp. 869-873 ◽  
Author(s):  
Ayano Sasaki-Crawley ◽  
Rosane Curtis ◽  
Michael Birkett ◽  
Apostolos Papadopoulos ◽  
Rod Blackshaw ◽  
...  

This paper demonstrates a simple novel in vitro method using Pluronic F-127 aqueous solution to study the development of the potato cyst nematode, Globodera pallida, in Solanum spp. without any need for sterilisation of either the plants or the nematodes. In this study, this method was successfully applied to comparative studies on the development of G. pallida in Solanum tuberosum (potato) or S. sisymbriifolium (sticky nightshade). The protocol described here could be useful for screening transgenic plants or different plant cultivars/species for their ability to allow development not only of G. pallida but also any other plant-parasitic nematodes.


2007 ◽  
Vol 8 (5) ◽  
pp. 701-711 ◽  
Author(s):  
CATHERINE J. LILLEY ◽  
MANJULA BAKHETIA ◽  
WAYNE L. CHARLTON ◽  
PETER E. URWIN

2021 ◽  
Vol 4 (2) ◽  
pp. 327-338
Author(s):  
Honey Raj Mandal ◽  
Shambhu Katel ◽  
Sudeep Subedi ◽  
Jiban Shrestha

Plant Parasitic Nematodes are small worm like transparent, bilateral symmetry, pseudocoelomate, multicellular, free living or parasitic microorganism which are predatory, aquatic, terrestrial, entopathogenic, ectoparasite, endoparasite, semi-endoparasite or sedentary. They cause substantial problems to major crops throughout the world, including vegetables, fruits, and grain crops. The root knot and cyst nematodes are economically important pests in numerous crops. Crop damage from nematodes is not readily apparent in most cases, and it often remains hidden by the many other factors limiting plant growth. In the past, the control of the nematodes has been based on the synthetic nematicides, the number of which has been drastically restricted in the EU because of their environmental side effects and subsequent restriction in European Union (EU) rules and regulations. Many other methods like cultural control, biological control, use of biotechnological tools and methods, use of resistant cultivars are tested and proven successful in controlling different species of nematodes all over the world. Alternatively, combinations of the different methods are proven to be highly effective both economically and environmentally.


2018 ◽  
Author(s):  
Anna Crisford ◽  
Fernando Calahorro ◽  
Elizabeth Ludlow ◽  
Jessica M.C. Marvin ◽  
Jennifer K. Hibbard ◽  
...  

AbstractPlant parasitic nematodes are microscopic pests that invade plant roots and cause extensive damage to crops worldwide. To investigate mechanisms underpinning their parasitic behaviour we used a chemical biology approach: We discovered that reserpine, a plant alkaloid known for its antagonism of the mammalian vesicular monoamine transporter VMAT and ability to impart a global depletion of synaptic biogenic amines in the nervous system, potently impairs the ability of the potato cyst nematode Globodera pallida to enter the host plant root. We show that this effect of reserpine is mediated by an inhibition of serotonergic signalling that is essential for activation of the stylet, a lance-like organ that protrudes from the mouth of the worm and which is used to pierce the host root to gain access. Prompted by this we identified core molecular components of G. pallida serotonin signalling encompassing the target of reserpine, VMAT; the synthetic enzyme for serotonin, tryptophan hydroxylase; the G protein coupled receptor SER-7 and the serotonin-gated chloride channel MOD-1. We found that inhibitors of tryptophan hydroxylase, SER-7 and MOD-1 phenocopy the plant protecting action of reserpine. Thus targeting the serotonin signalling pathway presents a promising new route to control plant parasitic nematodes.SummaryIndian snakeroot, an herbal medicine prepared from the roots of the shrub Rauwolfia serpentina, has been used for centuries for its calming action. The major active constituent is reserpine which works by depleting a specific class of mood regulating chemical in the brain, the biogenic amines. We have discovered a remarkable effect of reserpine on a pest of global concern, the plant parasitic nematodes. These microscopic worms invade the roots of crops presenting a severe threat to food production. We show that reserpine disables serotonin signalling in the worm’s ‘brain’ that regulates the rhythmic thrusting of the stylet: a lance-like structure that protrudes from its mouth to pierce the plant root and which is essential to its parasitic lifecycle. Thus, reserpine joins nicotine as another intriguing example of Nature evolving its own protection against pests. We have identified key components of the serotonin signalling pathway in the potato cyst nematode Globodera pallida and show that chemicals that target these sites inhibit the ability of the nematode to invade its host plant. We conclude that biogenic amine transmitters are intimately involved in the worm’s parasitic behaviour and provide a new discrete route to crop protection.


Plant Disease ◽  
2021 ◽  
Author(s):  
İmren Mustafa ◽  
Göksel Özer ◽  
Timothy Paulitz ◽  
Alexei Morgounov ◽  
Abdelfattah A. Dababat

Kazakhstan is one of the biggest wheat producers, however, its wheat production is far below the average international wheat production standard due to biotic and abiotic stressors. Plant-parasitic nematodes are devastating for cereal production systems worldwide. A comprehensive survey was conducted in 2019 to identify plant-parasitic nematodes associated with wheat in different locations of central, eastern, and south-eastern Kazakhstan. The results revealed 33 root-lesion and 27 cyst nematode populations from the 77 localities sampled. These two genera occurred in separate or in mixed populations. The root-lesion populations were identified as Pratylenchus neglectus and P. thornei while all cyst nematodes were identified as Heterodera filipjevi. The identification of nematodes was firstly performed based on morphological and morphometric features and confirmed by BLAST and phylogenetic analyses based on the internal transcribed spacer and the D2-D3 expansion located in the 28S gene of ribosomal DNA for CCN and RLN populations, respectively. Pratylenchus neglectus and P. thornei populations from Kazakhstan showed a high similarity with the American, European, and Asian populations. Heterodera filipjevi populations formed a well-supported cluster with the corresponding populations from different countries and showed a slightly intraspecific polymorphism. Kazakhstan populations of H. filipjevi may have multiple introductions in Kazakhstan due to the divergence among them. The results of this study are of great importance for breeding programs and will enable awareness to extension advisors to develop measures to control these nematodes in cereal cropping areas in Kazakhstan.


Plant Disease ◽  
2021 ◽  
Author(s):  
Andrea Caroline Ruthes ◽  
Paul Dahlin

Globodera rostochiensis and Globodera pallida are some of the most successful and highly specialized plant-parasitic nematodes, and appear among the most regulated quarantine pests globally. In Switzerland, they have been monitored by annual surveys since their first detection in Swiss soil, in 1958. The dataset created was reviewed to give an overview of the development and actual status of PCN in Switzerland. Positive fields represent 0.2% of all the samples analyzed, and currently their distribution is limited to central-west and western Switzerland, suggesting that new introduction of PCN and the spread of the initial introduced PCN populations did not occur. In this way, the integrated management used in Switzerland appears to be effective. However, the increasing availability of potato varieties with resistance to G. rostochiensis and the limited availability of varieties with resistance to G. pallida, together with other biotic and abiotic factors promoted changes in the dominance of either species. Consequently, an extended monitoring program would be of interest to Swiss farmers, to avoid favoring virulent traits that could be present within Swiss Globodera populations.


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