Root-knot nematode

Last updated

Root-knot nematode
A juvenile root-knot nematode (Meloidogyne incognita) penetrates a tomato root - USDA-ARS.jpg
Larva of root-knot nematode, Meloidogyne incognita, magnified 500×, shown here penetrating a tomato root
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Tylenchida
Family: Heteroderidae
Genus: Meloidogyne
Göldi, 1889
Species

Meloidogyne hapla
Meloidogyne incognita
Meloidogyne enterolobii syn. M. mayaguensis
...

Contents

Root-knot nematodes are plant-parasitic nematodes from the genus Meloidogyne. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause approximately 5% of global crop loss. [1] Root-knot nematode larvae infect plant roots, causing the development of root-knot galls that drain the plant's photosynthate and nutrients. Infection of young plants may be lethal, while infection of mature plants causes decreased yield.

Economic impact

Root-knot nematodes (Meloidogyne spp.) are one of the three most economically damaging genera of plant-parasitic nematodes on horticultural and field crops. Root-knot nematodes are distributed worldwide, and are obligate parasites of the roots of thousands of plant species, including monocotyledonous and dicotyledonous, herbaceous and woody plants. The genus includes more than 90 species, [2] with some species having several races. Four Meloidogyne species ( M. javanica, M. arenaria, M. incognita, and M. hapla ) are major pests worldwide, with another seven being important on a local basis. [3] Meloidogyne occurs in 23 of 43 crops listed as having plant-parasitic nematodes of major importance, ranging from field crops, through pasture and grasses, to horticultural, ornamental and vegetable crops. [4] If root-knot nematodes become established in deep-rooted, perennial crops, control is difficult and options are limited.[ citation needed ]

Meloidogyne spp. were first reported in cassava by Neal in 1889. [5] Damage on cassava is variable depending on cultivar planted, and can range from negligible to serious. [6] Early-season infection leads to worse damage. [7] In most crops, nematode damage reduces plant health and growth; in cassava, though, nematode damage sometimes leads to increased aerial growth as the plants try to compensate. This possibly enables the plant to maintain a reasonable level of production. Therefore, aerial correlations to nematode density can be positive, negative or not at all. [8] Vegetable crops grown in warm climates can experience severe losses from root-knot nematodes, and are often routinely treated with a chemical nematicide. Root-knot nematode damage results in poor growth, a decline in quality and yield of the crop and reduced resistance to other stresses (e.g. drought, other diseases). A high level of damage can lead to total crop loss. Nematode-damaged roots do not use water and fertilisers as effectively, leading to additional losses for the grower. In cassava, it has been suggested that levels of Meloidogyne spp. that are sufficient to cause injury rarely occur naturally. [8] However, with changing farming systems, in a disease complex or weakened by other factors, nematode damage is likely to be associated with other problems. [9]

Root-knot galls Nematode nodules.jpg
Root-knot galls

Control

Root-knot nematodes can be controlled with biocontrol agents Paecilomyces lilacinus , Pasteuria penetrans [10] and Juglone. [11]

Life cycle

All nematodes pass through an embryonic stage, four juvenile stages (J1–J4) and an adult stage. Juvenile Meloidogynes parasites hatch from eggs as vermiform, second-stage juveniles (J2), the first moult having occurred within the egg. Newly hatched juveniles have a short free-living stage in the soil, in the rhizosphere of the host plants. They may reinvade the host plants of their parent or migrate through the soil to find a new host root. J2 larvae do not feed during the free-living stage, but use lipids stored in the gut. [3]

An excellent model system for the study of the parasitic behaviour of plant-parasitic nematodes has been developed using Arabidopsis thaliana as a model host. [12] The Arabidopsis roots are initially small and transparent, enabling every detail to be seen. Invasion and migration in the root was studied using M. incognita. [13] Briefly, second stage juveniles invade in the root elongation region and migrate in the root until they became sedentary. Signals from the J2 promote parenchyma cells near the head of the J2 to become multinucleate [14] to form feeding cells, generally known as giant cells, from which the J2 and later the adults feed. [15] Concomitant with giant cell formation, the surrounding root tissue gives rise to a gall in which the developing juvenile is embedded. Juveniles first feed from the giant cells about 24 hours after becoming sedentary.[ citation needed ]

After further feeding, the J2s undergo morphological changes and become saccate. Without further feeding, they moult three times and eventually become adults. In females, which are close to spherical, feeding resumes and the reproductive system develops. [3] The life span of an adult female may extend to three months, and many hundreds of eggs can be produced. Females can continue egg laying after harvest of aerial parts of the plant and the survival stage between crops is generally within the egg.[ citation needed ]

The length of the life cycle is temperature-dependent. [16] [17] The relationship between rate of development and temperature is linear over much of the root-knot nematode life cycle, though it is possible the component stages of the life cycle, e.g. egg development, host root invasion or growth, have slightly different optima. Species within the genus Meloidogyne also have different temperature optima. In M. javanica , development occurs between 13 and 34 °C, with optimal development at about 29 °C. [18]

Gelatinous matrix

Root-knot nematode females lay eggs into a gelatinous matrix produced by six rectal glands and secreted before and during egg laying. [19] The matrix initially forms a canal through the outer layers of root tissue and later surrounds the eggs, providing a barrier to water loss by maintaining a high moisture level around the eggs. [20] As the gelatinous matrix ages, it becomes tanned, turning from a sticky, colourless jelly to an orange-brown substance which appears layered. [21]

Egg formation and development

Egg formation in M. javanica has been studied in detail, [22] and is similar to egg formation in the well studied, free-living nematode Caenorhabditis elegans. [23] Embryogenesis has also been studied, and the stages of development are easily identifiable with a phase contrast microscope following preparation of an egg mass squash. The egg is formed as one cell, with two-cell, four-cell and eight-cell stages recognisable. Further cell division leads to the tadpole stage, with further elongation resulting in the first stage juvenile, which is roughly four times as long as the egg. The J1 stage of C. elegans has 558 cells, and the J1 of M. javanica likely has a similar number, since all nematodes are morphologically and anatomically similar. [23] The egg shell has three layers, with the vitelline layer outermost, then a chitinous layer and a lipid layer innermost.

Egg hatching

Preceded by induced changes in eggshell permeability, hatching may involve physical and/or enzymatic processes in plant-parasitic nematodes. [24] Cyst nematodes, such as Globodera rostochiensis, may require a specific signal from the root exudates of the host to trigger hatching. Root-knot nematodes are generally unaffected by the presence of a host, but hatch freely at the appropriate temperature when water is available. However, in an egg mass or cyst, not all eggs will hatch when the conditions are optimal for their particular species, leaving some eggs to hatch at a later date. Ammonium ions have been shown to inhibit hatching and to reduce the plant-penetration ability of M. incognita juveniles that do hatch. [25]

Reproduction

Root-knot nematodes exhibit a range of reproductive modes, including sexuality (amphimixis), facultative sexuality, meiotic parthenogenesis (automixis) and mitotic parthenogenesis (apomixis).

Species

Related Research Articles

Northern root-knot nematode is a species of vegetable pathogens which produces tiny galls on around 550 crop and weed species. They invade root tissue after birth. Females are able to lay up to 1,000 eggs at a time in a large egg mass. By surviving harsh winters, they can survive in cold climates.

<i>Meloidogyne incognita</i> Nematode worm, plant disease, many hosts

Meloidogyne incognita, also known as the southern root-nematode or cotton root-knot nematode is a plant-parasitic roundworm in the family Heteroderidae. This nematode is one of the four most common species worldwide and has numerous hosts. It typically incites large, usually irregular galls on roots as a result of parasitism.

<i>Rotylenchulus reniformis</i> Species of roundworm

Rotylenchulus reniformis, the reniform nematode, is a species of parasitic nematode of plants with a worldwide distribution in the tropical and subtropical regions.

<i>Meloidogyne arenaria</i> Species of roundworm

Meloidogyne arenaria is a species of plant pathogenic nematodes. This nematode is also known as the peanut root knot nematode. The word "Meloidogyne" is derived from two Greek words that mean "apple-shaped" and "female". The peanut root knot nematode, M. arenaria is one of the "major" Meloidogyne species because of its worldwide economic importance. M. arenaria is a predominant nematode species in the United States attacking peanut in Alabama, Florida, Georgia, and Texas. The most damaging nematode species for peanut in the USA is M. arenaria race 1 and losses can exceed 50% in severely infested fields. Among the several Meloidogyne species that have been characterized, M. arenaria is the most variable both morphologically and cytologically. In 1949, two races of this nematode had been identified, race 1 which reproduces on peanut and race 2 which cannot do so. However, in a recent study, three races were described. López-Pérez et al (2011) had also studied populations of M. arenaria race 2, which reproduces on tomato plants carrying the Mi gene and race 3, which reproduces on both resistant pepper and tomato.

<i>Meloidogyne javanica</i> Species of roundworm

Meloidogyne javanica is a species of plant-pathogenic nematodes. It is one of the tropical root-knot nematodes and a major agricultural pest in many countries. It has many hosts. Meloidogyne javanica reproduces by obligatory mitotic parthenogenesis (apomixis).

Pratylenchus brachyurus is a plant parasitic nematode.

<i>Pratylenchus penetrans</i> Species of roundworm

Pratylenchus penetrans is a species of nematode in the genus Pratylenchus, the lesion nematodes. It occurs in temperate regions worldwide, regions between the subtropics and the polar circles. It is an animal that inhabits the roots of a wide variety of plants and results in necrotic lesions on the roots. Symptoms of P. penetrans make it hard to distinguish from other plant pathogens; only an assay of soil can conclusively diagnose a nematode problem in the field. P. penetrans is physically very similar to other nematode species, but is characterized by its highly distinctive mouthpiece. P. penetrans uses its highly modified mouth organs to rupture the outer surface of subterranean plant root structures. It will then enter into the root interior and feed on the plant tissue inside. P. penetrans is considered to be a crop parasite and farmers will often treat their soil with various pesticides in an attempt to eliminate the damage caused by an infestation. In doing this, farmers will also eliminate many of the beneficial soil fauna, which will lead to an overall degradation of soil quality in the future. Alternative, more environmentally sustainable methods to control P. penetrans populations may be possible in certain regions.

Hirschmanniella oryzae, i.e. rice root nematode (RRN), is among the major pests of rice and is the most common plant-parasitic nematode found on irrigated rice. Recent modifications in cultivation practices have led to a substantial increase in rice production, which has been accompanied by heightened levels of RRN. The proportional increases in RRN with rice production can be explained by the nematode's impeccable adaptation towards constantly flooded conditions in which irrigated rice is often being grown.

Meloidogyne brevicauda is a plant-parasitic nematode. It is also called tea root-knot nematode, mature tea nematode or Indian root-knot nematode. It is a member of the root-knot nematodes, which was identified by C. A. Loos in 1953 in Sri Lanka.

<i>Paratylenchus hamatus</i> Species of roundworm

Paratylenchus hamatus, the fig pin nematode, is a species of migratory plant endoparasites, that causes lesions on plant roots resulting in symptoms of chlorosis, wilting and ultimately yield losses. They move and feed on different parts of host tissue throughout their life cycle in order to find enough susceptible host tissue to survive and reproduce. A wide range of host plant species are susceptible to the fig pin nematode, including many valuable fruit and vegetable crops such as figs, carrots and celery. They are also commonly found associated with woody perennials in California. P. hamatus inhabits soils in both Europe and North America, and was originally isolated from fig in central California in 1950.

Xiphinema americanum, the American dagger nematode, is a species of plant pathogenic nematodes. It is one of many species that belongs to the genus Xiphinema. It was first described by N. A. Cobb in 1913, who found it on both sides of the United States on the roots of grass, corn, and citrus trees. Not only is Xiphinema americanum known to vector plant viruses, but also X. americanum has been referred to as "the most destructive plant parasitic nematode in America", and one of the four major nematode pests in the Southeastern United States.

Tylenchulus semipenetrans, also known as the citrus nematode or citrus root nematode, is a species of plant pathogenic nematodes and the causal agent of slow decline of citrus. T. semipenetrans is found in most citrus production areas and diverse soil textures worldwide. Their feeding strategy is semi-endoparasitic and has a very narrow host range among commonly grown crops. These nematodes are considered as major plant-parasitic nematode because they can cause 10-30% losses reported on citrus trees. They also parasitize other hosts such as olive, grape, persimmon and lilac. The citrus nematode was first discovered in California in 1913 by J. R. Hodges, a horticultural inspector for Los Angeles County, and was later described and named by Nathan Cobb that year. T. semipenetrans is the only species of Tylenchulidae that are economically important to agriculture.

Mesocriconema xenoplax is a species of plant parasitic nematodes. Nematodes of this particular species are collectively called ring nematodes.

There are many plant-parasitic species in the root-knot nematode genus (Meloidogyne) that attack coffee such as M. incognita, M. arenaria, M. exigua, M. javanica and M. coffeicola. Study has already shown interspecific variability coffee, in which show how this species can be adapting to new hosts and environments.

Meloidogyne enterolobii was originally described from a population collected from the pacara earpod tree in China in 1983. In 2001 it was reported for the first time in the continental USA in Florida. M. enterolobii is now considered one of the most important root-knot nematode species because of its ability of reproducing on root-knot nematode-resistant bell pepper and other economically important crops.

Globodera tabacum, commonly known as a tobacco cyst nematode, is a plant parasitic nematode that mainly infests the tobacco plant, but also plants in family Solanaceae.

<i>Purpureocillium lilacinum</i> Species of fungus

Purpureocillium lilacinum is a species of filamentous fungus in the family Ophiocordycipitaceae. It has been isolated from a wide range of habitats, including cultivated and uncultivated soils, forests, grassland, deserts, estuarine sediments and sewage sludge, and insects. It has also been found in nematode eggs, and occasionally from females of root-knot and cyst nematodes. In addition, it has frequently been detected in the rhizosphere of many crops. The species can grow at a wide range of temperatures – from 8 to 38 °C for a few isolates, with optimal growth in the range 26 to 30 °C. It also has a wide pH tolerance and can grow on a variety of substrates. P. lilacinum has shown promising results for use as a biocontrol agent to control the growth of destructive root-knot nematodes.

Heterodera zeae, the corn cyst nematode (CCN), is a plant parasitic nematode that feeds on Zea mays (maize/corn). The CCN has a limited economic impact worldwide due to its high soil temperature requirements.

Pasteuria is a genus of mycelial and endospore-forming, nonmotile gram-positive bacteria that are obligate parasites of some nematodes and crustaceans. The genus of Pasteuria was previously classified within the family Alicyclobacillaceae, but has since been moved to the family Pasteuriaceae.

Mononchoides fortidens, of the order Diplogasterida, is a free-living predacious nematode that feeds on both nematodes and bacteria . The predatory behavior of this nematode presents the opportunity to use it as a bio-control agent against other plant parasitic nematodes. It has been shown to have a preference for the second stage juveniles of Meloidogyne incognita.

References

  1. ↑ Sasser JN, Carter CC: Overview of the International Meloidogyne Project 1975–1984. In An Advanced Treatise on Meloidogyne. Edited by: Sasser JN, Carter CC. Raleigh: North Carolina State University Graphics; 1985:19–24.
  2. ↑ Moens, Maurice, Roland N Perry, and James L Starr. 2009. "Meloidogyne Species: a Diverse Group of Novel and Important Plant Parasites." In Root-knot Nematodes, ed. Roland N Perry, Maurice Moens, and James L Starr, 1–17. Wallingford, UK: CABI Publishing.
  3. 1 2 3 Eisenback, J. D. & Triantaphyllou, H. H. 1991 Root-knot Nematodes: Meloidogyne species and races. In: Manual of Agricultural Nematology, W. R. Nickle. (Ed). Marcel Dekker, New York. pp 281–286.
  4. ↑ Stirling, G. R.; Stanton, J. M.; Marshall, J. W. (1992). "The importance of plant-parasitic nematodes to Australian and New Zealand agriculture". Australasian Plant Pathology. 21 (3): 104–115. doi:10.1071/app9920104. S2CID   30012090.
  5. ↑ Neal, J. C. 1889. The root-knot disease of the peach, orange and other plants in Florida due to the work of Anguillula Bull. I.S. Bur. Ent.20.31pp.
  6. ↑ Jatala, P., bridge, J. 1990. Nematode parasites of root and tuber crops. In Plant parasitic nematodes in sub-tropical and tropical agriculture., pp 137-180. Luc, M., Sikora, R.A., Bridge, J., CABI Publishing, Wallingford, UK.
  7. ↑ Makumbi-kidza, N. N., Speijer and Sikora R. A. 2000. Effects of Meloidogyne incognita on growth and storage-root formation of cassava (Manihot esculenta). J Nematol.; 32(4S): 475–477.
  8. 1 2 Gapasin, R.M. 1980. Reaction of golden yellow cassava to Meloidogyne spp. Inoculation. Annals of Tropical Research 2:49–53.
  9. ↑ Theberge, R. L. (eds). 1985. Common African Pests and Diseases of cassava, Yam, Sweet Potato and Cocoyam. International Institute of Tropical Agriculture (IITA). Ibadan, Nigeria 107 p.
  10. ↑ Charles, Lauren; Carbone, Ignazio; Davies, Keith G.; Bird, David; Burke, Mark; Kerry, Brian R.; Opperman, Charles H. (2005). "Phylogenetic analysis of Pasteuria penetrans by use of multiple genetic loci". Journal of Bacteriology. 187 (August 2005): 5700–5708. doi:10.1128/JB.187.16.5700-5708.2005. PMC   1196054 . PMID   16077116.
  11. ↑ Dama, L.B.; Poul, B.N.; Jadhav, B.V.; Hafeez, M.D. (1999). "Effect of Herbal "Juglone" on Development of the plant parasitic nematode (Meloidogyne spp.) on Arachis hypogaea". Journal of Ecotoxicology and Environmental Monitoring. 9: 73–76.
  12. ↑ Sijmons, P. C.; Grundler, F. M. W.; von Mende, N.; Burrows, P. R.; Wyss, U. (1991). "Arabidopsis thalliana as a new model host for plant-parasitic nematodes". The Plant Journal. 1 (2): 245–254. doi:10.1111/j.1365-313x.1991.00245.x.
  13. ↑ Wyss, U., Grundler, F.M.W. & Munch, A. 1992 The parasitic behaviour of second stage juveniles of Meloidogyne incognita in roots of Arabidopsis thaliana. Nematologica, 38, 98–111.
  14. ↑ Hussey, R. S. & Grundler, F. M. W. 1998 Nematode parasitism of plants. In: The Physiology and Biochemistry of free-living and plant-parasitic nematodes. Perry, R. N. & Wright, D. J. (Eds), CABI Publishing, UK. pp 213 – 243.
  15. ↑ Sijmons, P. C.; Atkinson, H. J.; Wyss, U. (1994). "Parasitic strategies of root nematodes and associated host cell responses". Annual Review of Phytopathology. 32: 235–259. doi:10.1146/annurev.phyto.32.1.235.
  16. ↑ Madulu, J. & Trudgill, D. L. 1994 Influence of temperature on Meloidogyne javanica. Nematologica, 40, 230–243.
  17. ↑ Trudgill, D. L. 1995 An assessment of the relevance of thermal time relationships to nematology. Fundamental and Applied Nematology, 18, 407–417.
  18. ↑ Bird, A. F.; Wallace, H.R. (1965). "The Influence of Temperature On Meloidogyne Hapla and M. Javanica". Nematologica. 11 (4): 581–589. doi:10.1163/187529265X00726.
  19. ↑ Maggenti, A. R. & Allen, M. W. 1960 The origin of the gelatinous matrix in Meloidogyne. Proceedings of the Helminthological Society of Washington, 27, 4–10.
  20. ↑ Wallace, H. R. 1968 The influence of soil moisture on survival and hatch of Meloidogyne javanica. Nematologica, 14, 231–242.
  21. ↑ Bird, A. F. 1958 The adult female cuticle and egg sac of the genus Meloidogyne Goeldi, 1887. Nematologica, 3, 205–212.
  22. ↑ McClure, M. A.; Bird, A. F. (1976). "The tylenchid (Nematoda) egg shell: formation of the egg shell in Meloidogyne javanica". Parasitology. 72: 29–39. doi:10.1017/s003118200004316x. S2CID   84455043.
  23. 1 2 Wood, W. B. 1988 Introduction to C.elegans. In::The Nematode Caenorhabditis elegans, W. B. Wood (Ed), Cold Spring Harbour Laboratory, New York. pp 1–16.
  24. ↑ Norton, D. C. & Niblack, T. L. 1991 Biology and ecology of nematodes. In: Manual of Agricultural Nematology, Nickle, W. R. (Ed), Marcel Dekker, New York. pp 47–68.
  25. ↑ Surdiman; Webster, J. M. (1995). "Effect of ammonium ions on egg hatching and second-stage juveniles of Meloidogyne incognita in axenic tomato root culture". Journal of Nematology. 27 (3): 346–352. PMC   2619617 . PMID   19277298.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.