Coffee root-knot nematode

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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 [1] [2] coffee, in which show how this species can be adapting to new hosts and environments.

Contents

Morphology and anatomy

Meloidogyne exigua females are small with medium stylet (12–14 µm) and strong basal knobs. [3] This genus has sexual dimorphism; females are swollen and males keep vermiform as adults. The female has a pear shape when swollen. It is not possible differentiate one species from other on coffee in the field due to coffee being a host of several species of Meloidogyne. M. exigua can be found in Brazil, Guatemala, Colombia and Costa Rica. M. coffeicola has a long neck and brownish body color. Its stylet is 15–17.6 µm long with no prominent knobs. Females also swell, less than M. exigua, however. This species is found in Brazil, exclusively. Another way to distinguish Meloidogyne species is by the perineal patterns. The perineal pattern involves anus, vagina and surrounding area. Each species has a unique pattern that can distinguish them, but only a trained nematologist is able to verify those small differences. Meloidogyne exigua's perineal pattern has a hexagonal shape, with a dorsal arch above the anus and lateral lines not very pronounced on the perineal pattern, [3] while M. coffeicola pattern have a more simple conformation with striations between vulva and anus forming a target. [4] Due to difficulties to identify Meloidogyne species just by perineal pattern, other reliable techniques were developed, such as Isoenzyme characterizations. Oliveira [5] reported difficulties to use perineal pattern and isoenzymes helped to confirm species without mistakes. M. exigua is distinguished by its esterase phenotypes E1 and E2, [5] while M. coffeicola by Est C2. [4]

Life cycle

Attracted by exudates released by the coffee roots, J2 nematode (migratory stage) moves toward to food source. The nematodes penetrate in the roots and search for a site to feed on. Several cells are selected to start uptaking food. Those cells are modified and grow bigger (hypertrophy) without cellular division. However, nuclei division start happening and many nuclei are produced inside generating giant cells. Surrounding cells will suffer hyperplasia and start cellular division wildly. For M. exigua, these cells will become galls, but not for M. coffeicola. [6] The nematode starts to swell and get a swollen shape as it molts through the juvenile stages until the adult stage. Many eggs will be produced by the female nematode, and released in a gelatinous mass. M. exigua lays its eggs under the epidermis, unlike M.coffeicola that lays them outside of the roots. [6] The juveniles that came out in the gelatinous mass will hatch and find a new feeding site and restart the cycle. Some juveniles may become males when the nematode population is high (competition), environmental condition are not favorable, or the plant is resistant. The life cycle of Meloidogyne exigua was reported to be around 35 days at 25–30 °C. [7]

Pathology

M. exigua causes galls on the root system, which are visible with the naked eye. Although, M. coffeicola does not produce galls it causes peeling and cracking of roots instead. Reduction of root system is observed, mostly because nematodes feed closer to xylem and phloem, where water and nutrients are transported into the plant. This blockage reduces root system development. Above ground symptoms include defoliation and leaf chlorosis leading to death of the plant.

Management

The first thing recommendation to control the gall nematodes is to plant healthy seeds in area not infested. Nematode-free seeds are important to avoid disseminating the pathogen to other areas. However, if areas are already contaminated, other measures will be needed. Some nematicides are still applied to stop J2 from infecting coffee plants. However, due phytotoxicity and high value their use became unpractical. Thus, new cultural methods started to be applied such as irrigation control, remove diseased plants, spacing rows and others not as common. M. exigua can survive for six months without the host, while M. coffeicola just survive for few days or weeks. [6] Thus, not planting host plants for a period greater than six months can eradicate both plant feeders. Grafting [8] is another method applied to control Meloidogyne species that attacks coffee. Resistant varieties are used as a support (stock) such Apoatã, [9] Nemaya, or other C. canephora varieties or hybrids. which will provide nutrients to the other variety on the top (scion) such Mundo Novo, that will be the one with flower and coffee fruit production. It is an easier method, that does not harm the environment. Other cultivar that is used to control M. exigua is IAPAR 59. It carries Mex-1 resistance gene, that causes hypersensitive response (HR) in the plant, [10] also having low reproductive factor to M. exigua. [9] This is a competitive variety with good agronomic factors.

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<i>Ficus citrifolia</i> Species of fig native to the Americas

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Root-knot nematode Genus of parasitic worms

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. 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.

<i>Radopholus similis</i> Species of roundworm

Radopholus similis is a species of nematode known commonly as the burrowing nematode. It is a parasite of plants, and it is a pest of many agricultural crops. It is an especially important pest of bananas and citrus, and it can be found on coconut, avocado, coffee, sugarcane, other grasses, and ornamentals. It is a migratory endoparasite of roots, causing lesions that form cankers. Infected plants experience malnutrition.

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

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.

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>

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.

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).

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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>

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.

Tylenchulus semipenetrans 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 and was later described and named by Nathan Cobb that year.

<i>Anguina agrostis</i>

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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.

Helicotylenchus is a genus of nematodes in the family Hoplolaimidae. They are known generally as spiral nematodes. They are found worldwide because they can live and survive in a wide range of habitats. They are among the most common parasitic nematodes of plants; found in corn, bananas, grass, soybeans.

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.

Root gall nematode Genus of roundworms

Root-gall nematodes are plant-parasitic nematodes from the genus Subanguina that affect grasses, including cereals, and some other plants, such as mugwort. They are distinct from the Root-knot nematodes which are from the genus Meloidogyne. So far around twenty-five separate species of Subanguina have been identified, although the most well-known and type species is Subanguina radicicola.

References

  1. ↑ Carneiro, R. M. D. G., Tigano, M. S., Randig, O., Almeida, M. R. A. & Sarah, J-Louis. 2004. Identification and genetic diversity of Meloidogyne spp. (Tylenchida: Meloidogynidae) on coffee from Brazil, Central America and Hawaii. Nematology 6: 287–298.
  2. ↑ Hernandez, A., Fargette, M. & Sarah, J-Louis. 2004. Characterisation of meloidogyne spp. (Tylenchida: Meloidogynidae) from coffee plantations in central America and Brazil. Nematology 6: 193–204.
  3. 1 2 Carneiro, M.D. G. & Cofcewicz, T. E. 2008. Taxonomy of Coffee-Parasitic root-knot nematodes, Meloidogyne spp. In: Souza, R. M (Ed). Plant-Parasitic nematodes of coffee. Campos dos Goytacazes, BR, springer, PP. 87–122.
  4. 1 2 Castro, J. M. C., Campos, V. P. &Dutra M. R. 2004. Ocorrência de Meloidogyne coffeicola em Cafeeiros do Município de Coromandel, Região do Alto Paranaíba em Minas Gerais. Fitop. bras. 29: 227.
  5. 1 2 Oliveira, D. S., Oliveira, R. D. L., Freitas, L. G., & Silva, R. V. 2005. Variability of Meloidogyne exigua on Coffee in the Zona da Mata of minas Gerais State, Brazil. Journal of Nematology 37 (3): 323–327.
  6. 1 2 3 Campos, V. P., Sivapalan, P. & Gnanapragasam, N. C. 1990. Nematode parasites of coffee, cocoa and tea. In: Luc, M., Sikora, R. A. & Bridge, J. (Eds). Plant Parasitic nematodes in subtropical and tropical agriculture. Wallingford, UK, CAB International, PP.387–430.
  7. ↑ D’Arc deLima, R., Ferraz, S. 1985. Biologia de Meloidogyne exigua. I. Desenvolvimento pos-embriogênico e efeito da temperatura na embriogênese. Revista Ceres 32: 339–348.
  8. ↑ Campos, V. P. & Silva, J. R .C. 2008. Management of Meloidogyne spp. in Coffee Plantation. In: Souza, R. M (Ed). Plant-Parasitic nematodes of coffee. Campos dos Goytacazes, BR, springer, PP. 149–164.
  9. 1 2 Salgado, S. M. L., Resende, M. L. V. & Campos, V. P. 2005. Reprodução de Meloidogyne exigua em cultivares de cafeeiros resistentes e suscetiveis. Fitopatol. Bras. 30: 413–415.
  10. ↑ Anthony, F., Topart, P., Martinez, A., Silva, M. & Nicole, M. 2005. Hypersensitive-like reaction conferred by the Mex-1 resistance gene against Meloidogyne exigua in coffee. Plant Pathology 54: 476–482.
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