The Parasitism of Root Knot Nematodes: A Mini review
Mohamed S Khalil*1, Amira E Mahmoud2, Mohamed A Ghorab3 and Esmail Ebrahim1
1Central Agricultural Pesticides Laboratory (CAPL), Agricultural Research Center (ARC), Egypt
2AgriculturalBotany Department, Alexandria University, Egypt
3National Institute of Oceanography and Fisheries (NIOF), Environmental Toxicology Laboratory, Central Laboratories Unit (CLU), Egypt
Submission: September 20, 2017; Published: September 25, 2017
*Corresponding author: Mohamed S Khalil, Central Agricultural Pesticides Laboratory (CAPL), Agricultural Research Center (ARC), Egypt, mail: melonema@gmail.com
How to cite this article: Mohamed S K, Amira E M, Mohamed A G, Esmail E. The Parasitism of Root Knot Nematodes: A Mini review. 2017;5(3): 555664. DOI:10.19080/IJESNR.2017.05.555664
Abstract
Phyto nematodes, or plant-parasitic nematodes, are considered to be among the most important economic pathogens around the world. Plant tissues are the main source of food for plant parasitic nematodes. There are thousands of nematodes genera, but the root- knot nematodes (Meloidogynespp.) were and still the most dominant and destructive genus around the world. Meloidogynespp. Cause an estimated an nualloss of $157 billion globally. Root-knot nematodes release certain proteins that modifying the plant cell wall to disrupt it, in addition to the mechanicals hearing by the stylet of nematodes. The parasitism proteins secreted by root- knot nematode might include plant cell wall modifying enzymes, besides proteins that are capable of localizing in the host plant cell nucleus, suppressors of host defense, proteins that can mimic plant proteins as reported in other cyst and root knot nematodes.
Keywords: Root-Knot Nematodes; Plant Cell-Wall; Life Cycle; Parasitism; Degrading Enzymes
Introduction
Plant parasitic nematodes (PPN) are tiny micro scopic worms and occur abundantly in soil. Moreover, plant parasitic ematodes are the hidden enemy of crops and are one of the many groups of harmful organisms which depend on plants for their survival and reproduction [1]. PPN infesting several growing crops, such as vegetables and leguminous crops, oil crops, fiber crops, grain crops and fruit trees next to weeds which are the secondary host to parasitic nematodes [2]. Among the root-knot nematodes, Meloidogynejavanica (Treub) Chitw., M.incognita (KofoidandWhite) Chitw., M.arenaria (Neal) Chitw., and M.hapla Chitw. are the major agronomic importance, being responsible for at least 90% of all damage caused by nematodes form any cultivated crops around the world [3,4].
The root-knot nematodes (Meloidogynespp.) are end parasitic & sedentary nematodes which complete their life cycle inside the plant tissues and produce large numbers of eggs, which accumulate in masses attached to their bodies. Otherwise, the common symptoms of the infestation with root-knot nematode are stunting, yellowing and wilting, but the major symptom is the gall formation in plant roots [2]. The estimated annual losses to world crops by plant parasitic nematodes are $118b [5]. Plant parasitic nematodes feed on living plant tissues, using an oral styled to puncture host cells. All plant nematodes inject enzymes (saliva), in to a host cell before feeding. The saliva stimulates cell enlargement and also liquefies part of the contents of the cells, which are then withdrawn by the nematode through its stylet. Therefore, this simple mini-review aimed to make a small notification, for those interesting by parasitism of root- knot nematodes and how nematodes degrade the plant cells wall. Also, it is helpful for those work or study in field of pest management to understand the parasitism mechanisms.
Life Cycle and Giant Cell Formation of Root-Knot Nematodes
The life cycle of root-knot nematode from egg to egg is complete in about 25 days at 27°C, but it could be increased or decreased expending on the levels of temperature (lower or higher). Each female lays approximately 500eggs in a gelatinous mass produced by the female from rectum glands. Embryo genesis within the egg is transformed to the second stage juvenile after the first molting. The second-stage juveniles (J2) considered the infectious stage which starts immediately seeking about the host [6]. Nematodes use their chemo receptors to find the host and this depending on the root exudates of the host plant [7]. Moreover, juveniles (J2) penetrate the root just behind the root tip and migrate between cells until staying near to vascular cylinder. The second-stage juveniles may migrate from within galls to adjacent parts of the root and cause new infections in the same root, or they may emerge from the root and infect other roots of the same plants or roots of other plants.
The second-stage juveniles (J2) induce about five to seven parenchyma tic root cells into multinucleate and hypertrophied feeding cells. These transformed root cells are the giant cells which function as specialized source to provide nutrients to the nematodeuntilre production. During feeding process, then nematode becomes sedentary, going through three molts before becoming a mature adult. Most RKNs reproduce by parthenogenesis [8]. Males migrate out of the plant and playnorolein reproduction. After the development of the pear shaped female, eggs are released on the root surface in a protective, gelatinous matrix. It is so easy to distinguish between male and female of root-knot nematodes through the morphological form. The males of root-knot nematodes are worm like and about 1.2 to 1.5mm long by 30 to 36μm India meter. Whereas, females in last stage are pear shaped and about 0. 40 to 1.30mm long by 0.27 to 0.75mm wide.
Giant-cells expand rapidly, reaching their full size during 2 or 3 weeks after onset of nematode feeding [9]. The induced cells by root-knot nematodes are between three to six giant-cells to feed from. The first sign of giant-cell induction is the formation of binucleate cells [10]. Giant cells have a very dense cytoplasm containing numerous mitochondria, plastids, ribosomes, a well- developed Golgi apparatus and smooth end oplasmicreticulum, generally organized in swirls [10]. The vacuole disappears and gives rise to many small vacuoles. To enhance solute up take from the vascular system, cell wall ingrowths develop in contact with the xylem. Thus, mature giant cells are metabolically active and act as transfer cells for the feeding nematode. Historically, Nemec was the first scientist who explains the mode of giant-cell information [11]. He mentioned that development of giant-cells occur by expansion of cell without degradation of cell wall. Also, he clarified that the cell extension is accompanied with repeated rounds of mitosis without cell wall formation providing an explanation for the high numbers of nuclei in these large cells.
Parasitism of Root-Knot Nematodes
Parasitism genes which found in root knot nematodes are responsible for production of Parasitism proteins that secreted by the nematode and play a direct role in plant parasitism [12]. The secreted proteins are mostly originated from the esophageal gland cells, but secretions from the chemo sensory amphids might also be important [13]. In most cases of parasitism the second stage juvenile (J2) is the infectious stage who initiate the parasitic relationship with the host by releasing their secretions into the root cells through its style which stimulate the root cells of the host to become specialized feeding cells (giant cells), which considered the essential and only source of nutrients for the nematode's survival [14,15]. Plant cell walls serve as obstacles.nematodes release a mixture of cell-wall-digesting enzymes to break structural plant cell walls [15]. Mean while, migratory plant nematodes that enter plant tissues facing additional obstacles to feeding through different tissues, as well as evasion of host defense [16]. Zenov'eva et al. [17] summarized several gene products isolated from sub-ventral glands of nematodes which included lipo protein, cellulose-binding protein, endo- glucanase, chitinase, pectinase and proteinase.
Enzymes Involved in Cell Wall Breakdown
Calreticulin: Calreticulin like proteins are also reported to be secreted from other plant parasitic nematodes and play a role in the interactions among parasite and host [18,19]. A calreticulin-like protein preceded by a signal peptide was also reported to be secreted from the sub-ventral glands of a root knot nematode [20].
Cellulase: After the hatching of eggs, the juveniles of root- knot nematodes are needed to penetrate the root of host plant to complete their life cycle. The main structural component of the plant cell wall is Cellulose which needs to degrade by Cellulase enzyme. Cellulases are responsible for the hydrolysis of β- 1, 4- glucosidic linkages. The Celluloses enzymes were identified in the sedentary nematode genre a as Meloidogyne, Heterodera and Globodera [21]. The plant cell wall digesting enzyme cellulose gene is already described for root knot nematodes [14,22,23].
Chorismate Mutase: The enzyme chorismatemutase is proved to be involved in early development of the feedings it as induced by plant parasitic nematodes, but how this enzyme alters the development of plant cells is not properly known [24]. The first animal chorismate mutasegene (Mj-cm-1) was cloned from Meloido gyne javanica and found to be expressed in the oesophageal gland cells of the nematode [25]. Chorismate mutase was also identified from soybean and potato cyst nematodes recently [26-28].
PectateLyase: Certain evidences proved that Pectatelyases enzymes are produced and released during the process of nematode penetration and migration or not at all during these dentary stages of the nematodes [14,29,30]. Pectatelyases enzymes were identified in many genre a such as Meloidogyne spp., Heterodera, Globodera and Bursaphelenchus spp. [14,31]. Moreover, some reports mentioned that the pectinase proteins obtained from root knot nematodes was of the type pectatelyase which is found in fungi and bacteria [32,33].
Polygalacturonase: The first recorded animal Polygalacturonases (PGs) enzymes were reproduced from Meloidogyneincognita [34]. Polygalacturonases are enzymes that catalyze the degradation of pectins which is major plant cell wall components, in another word, the poly galacturonase which produced by M.incognita could play an important role in weakening the plant cell wall so froot tissue during nematode penetration and inter cellular migration by the parasite like other nematode parasitism genes [35]. Also, PGs enzymes stimulate the hydrolysis of pectic-polygalacturonic acid and turn release oligo galacturonides.
Xylanase: Xylan is the widest spread poly saccharide in nature after cellulose. The functional characterizations of endo-1, 4-β-xylanase was obtained for the first time from the southern root-knot nematode (Meloidogyneincognita). The nematode endo-xylanase has similarity to bacteria lendo-xylanases [36].
Conclusion
The main purpose of this review is to throw alight and or make an instant notification about the parasitism of plant parasitic nematodes especially root-knot nematodes (RKN). In this review we can clarify some points about the importance of some modifying enzymes which play role in penetration processes, besides the mechanical penetration by the stylet. Cellulase, Polygalacturonase, Xylanase and others which considered cell wall modifying enzymes' were proved to be released by certain plant parasitic nematodes including RKN.
References
- Khan MR (2008) Current Options for Managing Nematodes Pest of Crops in India. Department of Agricultural Entomology, West Bengal, India.
- Khalil MS (2013) Alternative approaches to manage plant parasitic nematodes. J Plant Pathol Microbiol 4(1): e105.
- Castagnone Sereno P (2002) Genetic variability in partheno genetic root-knot nematodes Meloido gyne spp and their ability to overcome plant resistance genes. Nematol 4: 605-608.
- Trifonova Z, KaradjovaJ, GeorgievaT (2009) Fungal parasites of the root-knot nematodes Meloidogyne spp. In southern Bulgaria. Estonian J Ecol 58(1): 47-52.
- Atkinson HJ, CJ Lilley, PE Urwin (2012) Strategies for Trans genic nematode control in developed and developing world crops. Food Bio technology and Plant Bio technology 23(2): 251-256.
- Doncaster CC, MK Seymour (1973) Exploration and selection of penetration site by Tylenchida. Nematol 19: 137-145.
- Huettel RN (1986) Chemical communicators in nematodes. J Nematol 18: 3-8.
- Castagnone Sereno P (2006) Genetic variability and adaptive evolution in partheno genetic root-knot nematodes. Heredity 96:282-289
- Bird AF (1972) Quantitative studies on the growth of syncytia induced in plants by root-knot nematodes. Int J Parasitol 2: 157-170.
- Jones MGK, Payne HL (1978) Early stages of nematode-induced giant cell formation in roots of Impatiens balsamina. J Nematol10: 70-84.
- Nemec B (1910) Das Problem der be fruch Tungs vorgange und and erezytologische Fragen. In: Vielkernige Riesenzell enin Heterodera- Gallen. Gebruder Borntraeger Berlin, pp. 151-173.
- Gao BR, Allen T Maier, EL Davis, TJ Baum, RS Hussey (2002) Identification of anewbeta-1,4-endo glucanase gene expressed in the esophageal sub ventral gland cells of Heterodera glycines. J Nematol 34: 12-15.
- Davis EL, RS Hussey, TJ Baum (2004) Getting to the roots of parasitism by nematodes. Trends Parasitol 20: 134-141.
- Huang G, R Dong, R Allen, EL Davis, TJ Baum , RS Hussey (2005) Two chorismate mutase genes from the root-knot nematode Meloidogyneincognita. Mol PlantPathol 6: 23-30.
- Baum TJ, RS Hussey, LE Davis (2007) Root-knot and cyst nematode parasitism genes: the molecular basis of plant parasitism. Genetic Eng 28: 17-43.
- Hussey RS, FM Grundler (1998) Nematode parasitism of plants. In: Perry RN Wright DJ (Eds), Physiology and bio chemistry of free-living and plant parasitic nematodes. CAB InternationalPress, Wallingford, UK, pp. 213-243.
- Zinove eva S, N Vasyukov, O Ozeretskovskaya (2004) Bio chemical aspects of plant interaction with phyto parasitic nematodes: A review. Appl Bio technol Microbiol 40: 111-119.
- Nakhasi HL, GP Pogue, RC Duncan, M Joshi, CD Atreya, et al. (1998) Implications of cal reticulin function in parasite biology. Parasitol Today 14: 157-160.
- Pritchard D, A Brown, G Kasper, PM celroy, A Loukas, et al. (1999) A hook worm allergen which strongly resembles cal reticulin. Parasite Immunol 21: 439-450.
- Jaubert S, TN Ledger, JB Laffaire, C Piotte, P Abad, MN Rosso (2002) Direct identification of style secreted proteins from root-knot nematodes by a proteomic approach. Mol Biochem Parasitol 121: 205211.
- Smant G, JPWG Stokkermans, YT Yan, JM De Boer, TJ Baum, et al. (1998) Endo genous cellulases in animals: Isolation of beta-1,4-endo glucanase genes from two species of plant-parasitic cyst nematodes. Proceedings of the National Academy of Sciences of the United States of America 95: 4906-4911.
- Huang G, R Dong, T Maier, R Allen, EL Davis, et al. (2003) Use of solidphase subtractive hybridization for the identification of parasitism gene candidates from the root-knot nematode Meloidogyneincognita. Mol PlantPathol 5: 217-222.
- Huang G, B Gao, T Maier, R Allen, EL Davis, TJ Baum, RS Hussey (2004) A profile of putative parasitism genes expressed in the esophageal gland cells of the root-knot nematode Meloidogyneincognita. Mol Plant Microbe 16: 376-381.
- Doyle EA, KN Lambert (2002) Meloido gyne javanica chorismate mutase1alters plant cell development. Mol Plant MicrobeIn 16: 123131.
- Lambert KN, KD Allen, IM Sussex (1999) Cloning and characterization of an esophageal-gland-specific chorismate mutase from the phyto parasitic nematode Meloidogynejavanica. Mol Plant Microbe 12: 328336.
- Bekal S, TL Niblack, KN Lambert (2003) A chorismate mutase from the soy bean cyst nematode Hetero dera glycines shows polymorphism that correlate with virulence. Mol Plant Microbe 1: 439-446.
- Gao B, R Allen, T Maier, EL davis, TJ Baum, RS Hussey (2003) The parasitome of the phyto nematodes Hetero dera glycines. Mol Plant Microbe In 16: 720-726.
- Jones JT, C Furlanetto, E Bakker, B Banks, V Blok, Q Chen, MP, A Prior (2005) Characterization of a chorismate mutase from the potato cyst nemato de Globo dera pallida. Mol Plant Pathol 4: 43-50.
- Rosso MN, B Favery, C Piotte, L Arthaud, JM DeBoer, et al. (1999) Isolation of ac DNA encoding a beta-1,4-endoglucanase in the root- knot nematode Meloidogyneincognita and expression analysis during plant parasitism. Mol Plant Microbe 12: 585-591.
- Goellner M, G Smant, JM DeBoer, TJ Baum, EL Davis (2000) Isolation of beta-1,4-endo glucanase genes from Globo dera tabacum and their expression during parasitism. J Nematol 32: 154-165.
- Vanholme B, J DeMeutter, T Tytgat, M VanMontagu, A Coomans, G Gheysen (2007) Secretions of plant-parasitic nematodes: a molecular update. Gene 332: 13-27.
- Popeijus H, H Overmars, J Jones, V Blok, A Goverse, et al. (2000] Enzymology -degradation of plant cell walls by anematode. Nature 406: 36-37.
- DeBoer JM, JPM cdermott, EL Davis, RS Hussey, H Popeijus, G Smant, T J Baum (2002) Cloning of aputative pecta telyase gene expressed in the sub ventral esophageal glands of Heterodera glycines. J Nematol 34: 9-11.
- Jaubert S, JB Laffaire, P Abad, MN Rosso (2002) A poly galacturonase of animal origin isolated from the root-knot nematode Meloidogyneincognita. FEBS Lett 522: 109-112.
- Brummell DA, MH Harpster (2001) Cell wall metabolism in fruits oftening and quality and its anipulation in trans genic plants. Plant Mol Biol 47: 311-340.
- Mitreva dautova M, E Roze, H Overmars, L DeGraaff, A Schots, et al.(2006) A symbiont-independentendo-1,4-beta-xylanase from the plant-parasitic nematode Meloidogyneincognita. Mol Plant Microbe 19: 521-529.