scholarly journals Effectors of Root-Knot Nematodes: An Arsenal for Successful Parasitism

2021 ◽  
Vol 12 ◽  
Author(s):  
Shounak Jagdale ◽  
Uma Rao ◽  
Ashok P. Giri
Keyword(s):  
Plant Immunity ◽  
Plant Defence ◽  
Giant Cells ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematodes ◽  
Feeding Sites ◽  
The Past ◽  
Complex Functions ◽  
Insight Into

Root-knot nematodes (RKNs) are notorious plant-parasitic nematodes first recorded in 1855 in cucumber plants. They are microscopic, obligate endoparasites that cause severe losses in agriculture and horticulture. They evade plant immunity, hijack the plant cell cycle, and metabolism to modify healthy cells into giant cells (GCs) – RKN feeding sites. RKNs secrete various effector molecules which suppress the plant defence and tamper with plant cellular and molecular biology. These effectors originate mainly from sub-ventral and dorsal oesophageal glands. Recently, a few non-oesophageal gland secreted effectors have been discovered. Effectors are essential for the entry of RKNs in plants, subsequently formation and maintenance of the GCs during the parasitism. In the past two decades, advanced genomic and post-genomic techniques identified many effectors, out of which only a few are well characterized. In this review, we provide molecular and functional details of RKN effectors secreted during parasitism. We list the known effectors and pinpoint their molecular functions. Moreover, we attempt to provide a comprehensive insight into RKN effectors concerning their implications on overall plant and nematode biology. Since effectors are the primary and prime molecular weapons of RKNs to invade the plant, it is imperative to understand their intriguing and complex functions to design counter-strategies against RKN infection.

How do nematodes get their sweets? Solute supply to sedentary plant-parasitic nematodes

Nematology ◽  
2007 ◽  
Vol 9 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Julia Hofmann ◽  
Florian Grundler
Keyword(s):  
Nutrient Supply ◽  
Heterodera Schachtii ◽  
Transport Systems ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Cyst Nematodes ◽  
Root Knot Nematodes ◽  
Feeding Sites ◽  
Inorganic Solutes ◽  
Nematode Development

AbstractSedentary cyst and root-knot nematodes withdraw large amounts of solutes from feeding structures induced in host roots. The feeding structures are specialised cells with a high metabolic activity and a tremendous capacity in translocation of nutrients. The required nutrients are provided by the plant transport systems – water and inorganic solutes from the xylem, assimilates such as sugars and amino acids from the phloem. Here we discuss the available data on the mechanisms by which nutrients are translocated into the nematode feeding sites. The interaction between Heterodera schachtii and Arabidopsis thaliana serves as a model system for cyst nematodes. In this case sufficient data are available to propose a conclusive concept for the mechanisms of nutrient flow: basically, in the early stages of nematode development syncytia are symplasmically isolated, so that transport proteins are responsible for the nutrient supply. Later, connections to the phloem via plasmodesmata are established, so that developing females are well supplied with assimilates. The interactions of root-knot nematodes with their hosts share a number of similarities but the data currently available are not sufficient to draw similar conclusions. As nutrient supply and functionality of feeding structures are the basis of biotrophic parasitism of sedentary nematodes, it is tempting to unravel the mechanisms by which both plant and nematodes influence each other via nutrient fluxes.

scholarly journals Marigolds (Tagetes spp.) for Nematode Management

EDIS ◽  
2007 ◽  
Vol 2007 (19) ◽  
Author(s):  
R. Krueger ◽  
K. E. Dover ◽  
Robert McSorley ◽  
K. H. Wang
Keyword(s):  
Mode Of Action ◽  
Cover Crop ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematodes ◽  
Fact Sheet ◽  
Nematode Management ◽  
Plant Parasitic

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)

scholarly journals Differences in Feeding Sites Induced by Root-Knot Nematodes, Meloidogyne spp., in Chickpea

2005 ◽  
Vol 95 (4) ◽  
pp. 368-375 ◽  
Author(s):  
Nicola Vovlas ◽  
Hava F. Rapoport ◽  
Rafael M. Jiménez Díaz ◽  
Pablo Castillo
Keyword(s):  
Giant Cell ◽  
Faba Bean ◽  
Nematode Species ◽  
Giant Cells ◽  
The Other ◽  
Root Knot Nematodes ◽  
Feeding Site ◽  
Feeding Sites ◽  
Meloidogyne Spp ◽  
Meloidogyne Species

Root-knot nematodes (Meloidogyne spp.) are sedentary, obligate endoparasites in plants, where they induce specialized feeding sites. The feeding sites act as strong metabolic sinks to which photosynthates are mobilized. The histopathological modifications in the nematode-induced feeding sites of artificially inoculated chickpea cv. UC 27 were qualitatively and quantitatively compared using five isolates of M. artiellia and one isolate each of M. arenaria, M. incognita, and M. javanica. All Meloidogyne isolates infected chickpea plants, but root gall thickening was significantly less for M. artiellia isolates than for the other Meloidogyne species. Nevertheless, neither the number of giant cells in the feeding site (averaging four to six) nor the area of individual giant cells was influenced by nematode species or isolate. However, the number of nuclei per giant cell was significantly smaller, and the maximum diameters of nuclei and nucleoli were significantly greater, in giant cells induced by M. artiellia isolates than in those induced by M. arenaria, M. incognita, or M. javanica. In a second experiment, M. artiellia-induced giant cells in faba bean and rapeseed also contained a small number of large nuclei.

scholarly journals Community Analysis of Nematodes Associated with Banana, Identification of root knot nematode and Evaluation the Susceptibility of Some Cultivars to Infection

2021 ◽  
Author(s):  
Radwa G. Mostafa ◽  
Aida M. El-Zawahry ◽  
Ashraf E. M. Khalil ◽  
Ameer E. Elfarash ◽  
Ali D. A. Allam
Keyword(s):  
Meloidogyne Javanica ◽  
Nematode Species ◽  
Common Species ◽  
Molecular Techniques ◽  
Control Measures ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Plant Parasitic

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.

Isoelectric focusing of proteins.

2021 ◽  
pp. 206-217
Author(s):  
Janete A. Brito
Keyword(s):  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematodes ◽  
Plant Parasitic

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.

scholarly journals Attachment tests of Pasteuria penetrans to the cuticle of plant and animal parasitic nematodes, free living nematodes and srf mutants of Caenorhabditis elegans

1999 ◽  
Vol 73 (1) ◽  
pp. 67-71 ◽  
Author(s):  
P. Mendoza de Gives ◽  
K.G. Davies ◽  
M. Morgan ◽  
J.M. Behnke
Keyword(s):  
Caenorhabditis Elegans ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Pasteuria Penetrans ◽  
Cyst Nematodes ◽  
Free Living ◽  
Root Knot Nematodes ◽  
C Elegans ◽  
Spore Attachment ◽  
Plant Parasitic

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.

scholarly journals Plant-Parasitic Nematodes Infecting Grapevine in Southern Spain and Susceptible Reaction to Root-Knot Nematodes of Rootstocks Reported as Moderately Resistant

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 ◽  
...  
Keyword(s):  
Vascular System ◽  
Southern Spain ◽  
Parasitic Nematodes ◽  
Histopathological Study ◽  
Plant Parasitic Nematodes ◽  
Population Densities ◽  
Root Knot Nematodes ◽  
Meloidogyne Spp ◽  
Plant Parasitic ◽  
Susceptible Response

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.

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
Keyword(s):  
Plant Root ◽  
Complex Interaction ◽  
The Other ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematodes ◽  
Plant Parasitism ◽  
Severe Reduction ◽  
Different Types ◽  
Plant Parasitic

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.

scholarly journals Nematode-Induced Changes of Transporter Gene Expression in Arabidopsis Roots

2005 ◽  
Vol 18 (12) ◽  
pp. 1247-1257 ◽  
Author(s):  
Ulrich Z. Hammes ◽  
Daniel P. Schachtman ◽  
R. Howard Berg ◽  
Erik Nielsen ◽  
Wolfgang Koch ◽  
...  
Keyword(s):  
Gene Families ◽  
Transcript Abundance ◽  
Giant Cells ◽  
Transport Processes ◽  
Transfer Cells ◽  
Parasitic Nematodes ◽  
Feeding Site ◽  
Feeding Sites ◽  
The Many ◽  
And Function

Root-knot plant-parasitic nematodes (Meloidogyne spp.) account for much of the damage inflicted to plants by nematodes. The feeding sites of these nematodes consist of “giant” cells, which have characteristics of transfer cells found in other parts of plants. Increased transport activity across the plasma membrane is a hallmark of transfer cells, and giant cells provide nutrition for nematodes; therefore, we initiated a study to identify the transport processes that contribute to the development and function of nematode-induced feeding sites. The study was conducted over a 4-week period, during which time the large changes in the development of giant cells were documented. The Arabidopsis ATH1 GeneChip was used to identify the many transporter genes that were regulated by nematode infestation. Expression of 50 transporter genes from 18 different gene families was significantly changed upon nematode infestation. Sixteen transporter genes were studied in more detail using real-time reverse-transcriptase polymerase chain reaction to determine transcript abundance in nematode-induced galls that contain giant cells and uninfested regions of the root. Certain genes were expressed primarily in galls whereas others were expressed primarily in the uninfested regions of the root, and a third group was expressed evenly throughout the root. Multiple transport processes are regulated and these may play important roles in nematode feeding-site establishment and maintenance.

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