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 Toward genetic modification of plant-parasitic nematodes: delivery of macromolecules to adults and expression of exogenous mRNA in second stage juveniles

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Olaf Kranse ◽  
Helen Beasley ◽  
Sally Adams ◽  
Andre Pires-daSilva ◽  
Christopher Bell ◽  
...  
Keyword(s):  
Food Security ◽  
Genetic Modification ◽  
The Body ◽  
Forward Genetics ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Cyst Nematodes ◽  
Plant Parasitic

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.

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 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.

Nematode management through genome editing.

2021 ◽  
pp. 408-413
Author(s):  
Shahid Siddique ◽  
Sebastian Eves-van den Akker
Keyword(s):  
Rna Interference ◽  
Recent Progress ◽  
Plant Pathogens ◽  
Low Cost ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Cyst Nematodes ◽  
Root Knot Nematodes ◽  
Plant Parasitic

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.

scholarly journals Towards genetic modification of plant-parasitic nematodes: delivery of macromolecules to adults and expression of exogenous mRNA in second stage juveniles

2020 ◽  
Author(s):  
Olaf Kranse ◽  
Helen Beasley ◽  
Sally Adams ◽  
Andre Pires da Silva ◽  
Chris Bell ◽  
...  
Keyword(s):  
Food Security ◽  
Genetic Modification ◽  
The Body ◽  
Forward Genetics ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Root Knot Nematode ◽  
Cyst Nematodes ◽  
Plant Parasitic

AbstractPlant-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 characterise the gonads of male Heterodera schachtii and Meloidogyne hapla in the context of spermatogenesis. We test and optimise 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.

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)

The genome and lifestage-specific transcriptomes of a plant-parasitic nematode and its host reveal susceptibility genes involved in trans-kingdom synthesis of vitamin B5

2021 ◽  
Author(s):  
Shahid Siddique ◽  
Zoran S. Radakovic ◽  
Clarissa Hiltl ◽  
Clement Pellegrin ◽  
Thomas J. Baum ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Crop Production ◽  
Susceptibility Genes ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Cyst Nematodes ◽  
Novel Approach ◽  
Vitamin B5 ◽  
Dual Analysis ◽  
Plant Parasitic

AbstractPlant-parasitic nematodes are a major, and in some cases a dominant, threat to crop production in all agricultural systems. The relative scarcity of classical resistance genes highlights a pressing need to identify new ways to develop nematode-resistant germplasm. Here, we sequence and assemble a high-quality genome of the model cyst nematode Heterodera schachtii to provide a platform for the first system-wide dual analysis of host and parasite gene expression over time, covering all major stages of the interaction. This novel approach enabled the analysis of the hologenome of the infection site, to identify metabolic pathways that were incomplete in the parasite but complemented by the host. Using a combination of bioinformatic, genetic, and biochemical approaches, we show that the highly atypical completion of vitamin B5 biosynthesis by the parasitic animal, putatively enabled by a horizontal gene transfer from a bacterium, is critically important for parasitism. Knockout of either the plant-encoded or the now nematode-encoded steps in the pathway blocks parasitism. Our experiments establish a reference for cyst nematodes, use this platform to further our fundamental understanding of the evolution of plant-parasitism by nematodes, and show that understanding congruent differential expression of metabolic pathways represents a new way to find nematode susceptibility genes, and thereby, targets for future genome editing-mediated generation of nematode-resistant crops.

scholarly journals Activation of hatching in diapaused and quiescent Globodera pallida

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
Keyword(s):  
Bursaphelenchus Xylophilus ◽  
Globodera Pallida ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Cyst Nematodes ◽  
Term Survival ◽  
C Elegans ◽  
Dauer Formation ◽  
Dorsal Gland

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.

scholarly journals Changes in mRNA Abundance within Heterodera schachtii-Infected Roots of Arabidopsis thaliana

2000 ◽  
Vol 13 (3) ◽  
pp. 309-315 ◽  
Author(s):  
Dieter Hermsmeier ◽  
Jennifer K. Hart ◽  
Marina Byzova ◽  
Steven R. Rodermel ◽  
Thomas J. Baum
Keyword(s):  
Arabidopsis Thaliana ◽  
Differential Display ◽  
Tissue Sample ◽  
Mrna Abundance ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Cdna Clones ◽  
Cyst Nematodes ◽  
Tissue Samples ◽  
Feeding Site

Gene expression changes in plant roots infected by plant-parasitic cyst nematodes are involved in the formation of nematode feeding sites. We analyzed mRNA abundance changes within roots of Arabidopsis thaliana during the early compatible interaction with Heterodera schachtii, the sugarbeet cyst nematode. Approximately 1,600 root sections, each containing a single parasitic nematode and its feeding site, and 1,600 adjacent, nematode-free root sections were excised from aseptic A. thaliana cultures 3 to 4 days after inoculation with H. schachtii. These tissue samples were termed infected and uninfected, respectively. Preparasitic nematodes were added to the uninfected tissue sample to maintain the nematode to plant tissue proportion. mRNA extracted from these two tissue samples was subjected to differential display analysis. Thirty-six cDNA clones corresponding to mRNA species with different abundance between both tissue samples were isolated. Of these clones, 24 were of A. thaliana origin and 12 were from H. schachtii. Differential display data predicted that the A. thaliana cDNA clones corresponded to 13 transcripts that were more abundant in the infected root sections and 11 transcripts that were more abundant in the uninfected root sections. H. schachtii cDNA clones were predicted to correspond to four transcripts that were more abundant in parasitic nematodes and to eight transcripts that were more abundant in preparasitic nematodes. In situ hybridization experiments confirmed the mRNA abundance changes in A. thaliana roots predicted by the differential display analyses for two A. thaliana clones.

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