Sedentary endoparasitic nematodes as a model for other plant parasitic nematodes

Nematology ◽  
2000 ◽  
Vol 2 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Godelieve Gheysen ◽  
Jan De Meutter ◽  
Tom Tytgat ◽  
August Coomans

AbstractPlant parasitic nematodes are known to cause a severe reduction in crop yield. Recently much effort is being put to engineering new nematode-resistant crop cultivars. Plant parasitic nematodes occur in three widely separated orders: Triplonchida, Dorylaimida and Tylenchida. All triplonchid and dorylaimid plant parasitic nematodes are migratory ectoparasites of roots. Within the Tylenchida, several different types of plant parasitism can be recognised. The sedentary endoparasites have the most complex interaction with their host, and are responsible for the vast majority of the agricultural damage. This causes most research to be concentrated on two groups of the sedentary endoparasitic nematodes: cyst- and root-knot nematodes. Both induce specialised feeding structures in the vascular cylinder of the plant root. The mechanism of phytoparasitism of the cyst- and root-knot nematodes is reviewed, of which some aspects will be applicable to the study of the other plant parasitic nematodes. Les nématodes parasites de plantes sont connus pour provoquer de sévères réductions dans les rendements des cultures. Actuellement, un effort se développe pour créer de nouveaux cultivars résistants aux nématodes. Les nématodes parasite de plantes appartiennent à trois ordres très éloignés: Triplonchida, Dorylaimida et Tylenchida. Tous les nématodes parasites de plantes chez les Triplonchida et Dorylaimida sont des ectoparasites migrateurs. Chez les Tylenchida, plusieurs types différents de parasitisme peuvent être identifiés. Les endoparasites sédentaires ont l’interaction la plus complexe avec leur hôte et sont responsables de la plus grande part des dégâts agricoles. C’est la raison pour laquelle la plupart des recherches sont concentrées sur deux groupes de nématodes endoparasites sédentaires, les nématodes à kystes et les nématodes galligènes. Ces deux groupes induisent des structures d’alimentation spécialisées dans les tissus vasculaires de la racine végétale. Le mécanisme parasitaire des nématodes à kystes et galligènes est revu, certaines de leurs caractéristiques pouvant être applicables à l’étude des autres nématodes phytoparasites.

EDIS ◽  
2007 ◽  
Vol 2007 (19) ◽  
Author(s):  
R. Krueger ◽  
K. E. Dover ◽  
Robert McSorley ◽  
K. H. Wang

ENY-056, an 8-page fact sheet by R. Krueger, K. E. Dover, R. McSorley, and K. -H. Wang, introduces homeowners to the problem of root-knot nematodes, the use of marigolds as an allelopathic cover crop for nematode suppression. It describes the mode of action, planting tips, considerations, and frequently asked questions. Includes references and tables showing susceptibility of marigold varieties to root-knot and plant-parasitic nematodes in Florida. Published by the UF Department of Entomology and Nematology, August 2007. ENY-056/NG045: Marigolds (Tagetes spp.) for Nematode Management (ufl.edu)


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.


Koedoe ◽  
1993 ◽  
Vol 36 (2) ◽  
Author(s):  
Esther Van den Berg

Ogma sekgwaum spec. nov. is described and figured from the Wilderness National Park. Females of this species are characterized by having one lip annulus with smooth, wavy margin, no submedian lobes, 53-59 body annuli, not strongly retrorse anteriorly, but becoming more so posteriorly with 12-14 longitudinal rows of projections at midbody, gradually lengthening and attenuating towards posterior end of body, longer on post-vulval ventral side of body, not branched or bifurcate with small protuberances on extreme tips which become hair-like on post-vulval projections and a 64-81 (im long stylet. Ogma coronatum Schuurmans Stekhoven & Teunissen, 1938 is described and figured with notes on the juvenile. Additional measure^ ments and SEM photographs are given for Criconema duplicivestitum (Andrassy, 1963) Raski & Luc, 1985 and measurements for Ogma naomiae Van den Berg, 1992. A list is given of the other known plant-parasitic nematodes also found. Neolobocriconema palaniense Muthukrishnan, 1987 is transferred to Ogma palaniense (Muthukrishnan, 1987) comb. nov.


2021 ◽  
Author(s):  
Radwa G. Mostafa ◽  
Aida M. El-Zawahry ◽  
Ashraf E. M. Khalil ◽  
Ameer E. Elfarash ◽  
Ali D. A. Allam

Abstract Background Plant-parasitic nematodes are extremely dangerous pests in a variety of economically important crops. The purpose of this study was a survey of all nematode species existing in banana from three sites in Assiut Governorate, Egypt and to characterize the most common species by morphological, morphometric and molecular techniques (PCR with species-specific primers). Then, study of resistance or sensitivity of some banana cultivars to root-knot nematodes.Methods and Results Four nematodes, Meloidogyne, Rotylenchulus reniformis, Helicotylenchus and Pratylenchus were isolated and identified from soil and root samples collected from banana plants. Most frequently occurring of plant parasitic nematode species in banana was Meloidogyne. Former research found differences in species and in resistance to root-knot nematodes among the examined plant cultivars. Identification of Root-knot nematodes by Characterize of morphometric, molecularly, morphological isolate of Meloidogyne related to banana plants. The results revealed that the identified nematode species, Meloidogyne javanica, is the most common plant-parasitic nematodes in all locations. Data on the susceptibility of the tested banana cultivars to M. javanica revealed that Grand Naine was highly susceptible (HS) however, Magraby was susceptible (S) but Williams and Hindi cultivars were moderately resistant (MR).Conclusions we concluded that a survey revealed the significant prevalence of Meloidogyne javanica, the most important nematodes on banana in Assiut. The morphometric, morphological, and molecular identification were harmonic with one another. In addition to the host response of certain banana cultivars, to M. javanica that resistance is of significance and can be helpful to incorporate through planning control measures for root- knot nematodes.


Author(s):  
Janete A. Brito

Abstract This chapter focuses on the efficacy of isoelectric focusing, which is a technique used for separating charged molecules by differences in their isoelectric point, in the examination of general proteins and specific enzymatic differences among plant parasitic nematodes, particularly the potato cyst and root knot nematodes.


Parasitology ◽  
2014 ◽  
Vol 142 (S1) ◽  
pp. S71-S84 ◽  
Author(s):  
DAVID McK. BIRD ◽  
JOHN T. JONES ◽  
CHARLES H. OPPERMAN ◽  
TAISEI KIKUCHI ◽  
ETIENNE G. J. DANCHIN

SUMMARYPlant-parasitic nematodes cause considerable damage to global agriculture. The ability to parasitize plants is a derived character that appears to have independently emerged several times in the phylum Nematoda. Morphological convergence to feeding style has been observed, but whether this is emergent from molecular convergence is less obvious. To address this, we assess whether genomic signatures can be associated with plant parasitism by nematodes. In this review, we report genomic features and characteristics that appear to be common in plant-parasitic nematodes while absent or rare in animal parasites, predators or free-living species. Candidate horizontal acquisitions of parasitism genes have systematically been found in all plant-parasitic species investigated at the sequence level. Presence of peptides that mimic plant hormones also appears to be a trait of plant-parasitic species. Annotations of the few genomes of plant-parasitic nematodes available to date have revealed a set of apparently species-specific genes on every occasion. Effector genes, important for parasitism are frequently found among those species-specific genes, indicating poor overlap. Overall, nematodes appear to have developed convergent genomic solutions to adapt to plant parasitism.


1999 ◽  
Vol 73 (1) ◽  
pp. 67-71 ◽  
Author(s):  
P. Mendoza de Gives ◽  
K.G. Davies ◽  
M. Morgan ◽  
J.M. Behnke

Populations of Pasteuria penetrans isolated from root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.) were tested for their ability to adhere to a limited selection of sheathed and exsheathed animal parasitic nematodes, free living nematodes, including Caenorhabditis elegans wild type and several srf mutants, and plant parasitic nematodes. The attachment of spores of Pasteuria was restricted and no spores were observed adhering to any of the animal parasitic nematodes either with or without their sheath or to any of the free living nematodes including C. elegans and the srf mutants. All spore attachment was restricted to plant parasitic nematodes; however, spores isolated from cyst nematodes showed the ability to adhere to other genera of plant parasitic nematodes which was not the case with spores isolated from root-knot nematodes. The results are discussed in relationship to cuticular heterogeneity.


Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1147-1154 ◽  
Author(s):  
Daniel Téliz ◽  
Blanca B. Landa ◽  
Hava F. Rapoport ◽  
Fernando Pérez Camacho ◽  
Rafael M. Jiménez-Díaz ◽  
...  

Incidence and nematode population densities of plant-parasitic nematodes were determined in 64 samples of soil and grapevine roots collected from commercial vineyards in southern Spain between October 2003 and May 2005. In addition, a histopathological study was done of root-stock roots naturally infected by root-knot nematodes (Meloidogyne spp.). Nematodes infecting the rootstocks were identified according to conventional procedures, and the Meloidogyne spp. were furthermore identified by sequence characterized amplified region-polymerase chain reaction (SCAR-PCR) and isozyme esterase analyses. The most important plant-parasitic nematodes detected, in order of decreasing frequency of total soil infestation and root infection (percentage of samples), were Mesocriconema xenoplax (34.4%), Meloidogyne incognita (26.6%), Meloidogyne javanica (14.1%), Xiphinema index (12.5%), Xiphinema italiae (10.9%), Pratylenchus vulnus (6.3%), and Meloidogyne arenaria (1.6%). No disease symptoms were observed on aboveground plant parts of the infected grapevines, except for plants in some fields where soil was infested with the virus-vector nematodes X. index and X. italiae. Those grapevines showed a yellow mosaic pattern in leaves early in the growing season and the internode shortening characteristic of infections by Grapevine fanleaf virus. Rootstocks infected by root-knot nematodes (Meloidogyne spp.) showed distorted feeder roots and large- to moderate-sized root galls, present either singly or in clusters. Histopathology of galled roots showed a typical susceptible response to infection by root-knot nematodes: cellular alterations were induced in the cortex, endodermis, pericycle, and vascular system, including giant-cell formation and severe distortion of vascular tissues. Most Meloidogyne egg masses ocurred on the surface of the galled root tissues, a position that could facilitate dispersion of the nematode eggs and juveniles and the occurrence of secondary infections. Some of the grapevine rootstocks surveyed in this study (Paulsen 1103, Richter 110, Rupestris du Lot, and SO4) had previously been reported to be resistant to Meloidogyne spp.; however, the population densities of these nematodes found in soil and roots sampled in the present study, as well as the compatible host-parasite relationship revealed by histopathology, indicate a susceptible response to Meloidogyne spp. from southern Spain.


EDIS ◽  
2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Mengyi Gu ◽  
Johan Desaeger

Florida leads the commercial production of caladiums, a popular ornamental. In Florida, root-knot, sting, and stubby root nematodes are found in caladium fields. Root-knot nematodes are considered the most important of all pests in caladiums that are grown in sand. This publication will help caladium growers understand what plant-parasitic nematodes are and current nematode management strategies for the caladium industry.


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