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Molecular Characterization of Three B-1,4-Endoglucanase Genes in Pratylenchus loosi and Functional Analysis of Pl-eng-2 Gene. PLANTS 2021; 10:plants10030568. [PMID: 33802850 PMCID: PMC8002642 DOI: 10.3390/plants10030568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/12/2021] [Accepted: 03/14/2021] [Indexed: 11/16/2022]
Abstract
Pratylenchus loosi is an important root-lesion nematode that causes damage to tea plantations in Iran and all over the world. The present study reports on the characterization and evolution of three ß-1,4-endoglucanase genes: Pl-eng-2, Pl-eng-3 and Pl-eng-4. The gene structure of Pl-eng-2 was fully determined with the predicted signal peptide and devoid of the linker domain and carbohydrate-binding domain, while Pl-eng-3 and Pl-eng-4 were only partially sequenced. The transcription of Pl-eng-2 was localized in the secretory esophageal glands of all life stages, but it was upregulated in male and female stages. The exon/intron structures of Pl-eng-2, Pl-eng-3 and Pl-eng-4 confirmed that they resulted from gene duplication followed by sequence and gene structure diversification with loss of the linker domain and carbohydrate-binding domain during evolution. A phylogenetic analysis further confirmed that nematode endoglucanases resulted from the horizontal gene transfer of a bacterial gene, as Pl-eng-3 showed sister relationships with the CelB cellulase of Bacillus subtilis. Silencing Pl-eng-2 by in vitro RNA interference produced a 60% decrease of the transcript level. The reproductive ability of silenced P. loosi showed a 35% reduction of eggs and larval stages compared to untreated nematodes, suggesting that this gene is involved in the early steps of invasion.
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Bauters L, Kyndt T, De Meyer T, Morreel K, Boerjan W, Lefevere H, Gheysen G. Chorismate mutase and isochorismatase, two potential effectors of the migratory nematode Hirschmanniella oryzae, increase host susceptibility by manipulating secondary metabolite content of rice. MOLECULAR PLANT PATHOLOGY 2020; 21:1634-1646. [PMID: 33084136 PMCID: PMC7694671 DOI: 10.1111/mpp.13003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/07/2020] [Accepted: 09/07/2020] [Indexed: 05/11/2023]
Abstract
Hirschmanniella oryzae is one of the most devastating nematodes on rice, leading to substantial yield losses. Effector proteins aid the nematode during the infection process by subduing plant defence responses. In this research we characterized two potential H. oryzae effector proteins, chorismate mutase (HoCM) and isochorismatase (HoICM), and investigated their enzymatic activity and their role in plant immunity. Both HoCM and HoICM proved to be enzymatically active in complementation tests in mutant Escherichia coli strains. Infection success by the migratory nematode H. oryzae was significantly higher in transgenic rice lines constitutively expressing HoCM or HoICM. Expression of HoCM, but not HoICM, increased rice susceptibility against the sedentary nematode Meloidogyne graminicola also. Transcriptome and metabolome analyses indicated reductions in secondary metabolites in the transgenic rice plants expressing the potential nematode effectors. The results presented here demonstrate that both HoCM and HoICM suppress the host immune system and that this may be accomplished by lowering secondary metabolite levels in the plant.
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Affiliation(s)
- Lander Bauters
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| | - Tina Kyndt
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| | - Tim De Meyer
- Department of Data Analysis and Mathematical ModellingFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| | - Kris Morreel
- VIB‐UGent Center for Plant Systems BiologyGhentBelgium
- Department of Plant Biotechnology and BioinformaticsFaculty of SciencesGhent UniversityGhentBelgium
| | - Wout Boerjan
- VIB‐UGent Center for Plant Systems BiologyGhentBelgium
- Department of Plant Biotechnology and BioinformaticsFaculty of SciencesGhent UniversityGhentBelgium
| | - Hannes Lefevere
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
| | - Godelieve Gheysen
- Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityGhentBelgium
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3
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Abstract
Background: The more than 4100 species of phytoparasitic nematodes are responsible for an estimated economic loss in the agricultural sector of nearly $125 billion annually. Knowing the main lines of research and concerns about nematodes that affect plants is fundamental. Methods: For this reason, an analysis using bibliometric data has been carried out, with the aim of tracing the state of world research in this field, as well as knowing the main lines of work, their priorities, and their evolution. Results: This will allow us to establish strategic lines for the future development of this research. Conclusions: The analysis has allowed us to detect that the interest in nematodes affecting plants has not stopped growing in the last decades, and that tomato, soybean, and potato crops are the ones that generate the most interest, as well as nematodes of the genus Meloidogyne and Globodera. Likewise, we have detected that the main lines of research in this field are focused on biological control and host–parasite interaction.
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Mantelin S, Thorpe P, Jones JT. Translational biology of nematode effectors. Or, to put it another way, functional analysis of effectors – what’s the point? NEMATOLOGY 2017. [DOI: 10.1163/15685411-00003048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
There has been a huge amount of work put into identifying and characterising effectors from plant-parasitic nematodes in recent years. Although this work has provided insights into the mechanisms by which nematodes can infect plants, the potential translational outputs of much of this research are not always clear. This short article will summarise how developments in effector biology have allowed, or will allow, new control strategies to be developed, drawing on examples from nematology and from other pathosystems.
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Affiliation(s)
- Sophie Mantelin
- Dundee Effector Consortium, Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Peter Thorpe
- Dundee Effector Consortium, Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - John T. Jones
- Dundee Effector Consortium, Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Biology Department, University of St Andrews, St Andrews, Fife KY16 9TZ, UK
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Li R, Rashotte AM, Singh NK, Lawrence KS, Weaver DB, Locy RD. Transcriptome Analysis of Cotton (Gossypium hirsutum L.) Genotypes That Are Susceptible, Resistant, and Hypersensitive to Reniform Nematode (Rotylenchulus reniformis). PLoS One 2015; 10:e0143261. [PMID: 26571375 PMCID: PMC4646469 DOI: 10.1371/journal.pone.0143261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 11/02/2015] [Indexed: 11/18/2022] Open
Abstract
Reniform nematode is a semi-endoparasitic nematode species causing significant yield loss in numerous crops, including cotton (Gossypium hirsutum L.). An RNA-sequencing analysis was conducted to measure transcript abundance in reniform nematode susceptible (DP90 & SG747), resistant (BARBREN-713), and hypersensitive (LONREN-1) genotypes of cotton (Gossypium hirsutum L.) with and without reniform nematode infestation. Over 90 million trimmed high quality reads were assembled into 84,711 and 80, 353 transcripts using the G. arboreum and the G. raimondii genomes as references. Many transcripts were significantly differentially expressed between the three different genotypes both prior to and during nematode pathogenesis, including transcripts corresponding to the gene ontology categories of cell wall, hormone metabolism and signaling, redox reactions, secondary metabolism, transcriptional regulation, stress responses, and signaling. Further analysis revealed that a number of these differentially expressed transcripts mapped to the G. raimondii and/or the G. arboreum genomes within 1 megabase of quantitative trait loci that had previously been linked to reniform nematode resistance. Several resistance genes encoding proteins known to be strongly linked to pathogen perception and resistance, including LRR-like and NBS-LRR domain-containing proteins, were among the differentially expressed transcripts mapping near these quantitative trait loci. Further investigation is required to confirm a role for these transcripts in reniform nematode susceptibility, hypersensitivity, and/or resistance. This study presents the first systemic investigation of reniform nematode resistance-associated genes using different genotypes of cotton. The candidate reniform nematode resistance-associated genes identified in this study can serve as the basis for further functional analysis and aid in further development of reniform a nematode resistant cotton germplasm.
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Affiliation(s)
- Ruijuan Li
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Aaron M. Rashotte
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Narendra K. Singh
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Kathy S. Lawrence
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, United States of America
| | - David B. Weaver
- Department of Crop, Soil and Environmental Sciences, Auburn University, Auburn, Alabama, United States of America
| | - Robert D. Locy
- Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America
- * E-mail:
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6
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Eves-van den Akker S, Lilley CJ, Jones JT, Urwin PE. Identification and characterisation of a hyper-variable apoplastic effector gene family of the potato cyst nematodes. PLoS Pathog 2014; 10:e1004391. [PMID: 25255291 PMCID: PMC4177990 DOI: 10.1371/journal.ppat.1004391] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 08/11/2014] [Indexed: 11/18/2022] Open
Abstract
Sedentary endoparasitic nematodes are obligate biotrophs that modify host root tissues, using a suite of effector proteins to create and maintain a feeding site that is their sole source of nutrition. Using assumptions about the characteristics of genes involved in plant-nematode biotrophic interactions to inform the identification strategy, we provide a description and characterisation of a novel group of hyper-variable extracellular effectors termed HYP, from the potato cyst nematode Globodera pallida. HYP effectors comprise a large gene family, with a modular structure, and have unparalleled diversity between individuals of the same population: no two nematodes tested had the same genetic complement of HYP effectors. Individuals vary in the number, size, and type of effector subfamilies. HYP effectors are expressed throughout the biotrophic stages in large secretory cells associated with the amphids of parasitic stage nematodes as confirmed by in situ hybridisation. The encoded proteins are secreted into the host roots where they are detectable by immunochemistry in the apoplasm, between the anterior end of the nematode and the feeding site. We have identified HYP effectors in three genera of plant parasitic nematodes capable of infecting a broad range of mono- and dicotyledon crop species. In planta RNAi targeted to all members of the effector family causes a reduction in successful parasitism. Sedentary plant parasitic nematodes are pathogens that invade plant roots and establish a feeding site. The feeding site is a specialist structure used by the nematode to support its development within the plant. The nematode secretes a suite of proteins, termed ‘effector proteins’ that are responsible for initiating and maintaining the feeding site. The nematode must also evade recognition by the plant defence systems throughout its lifecycle that can last for many weeks. We describe a diverse and variable effector gene family (HYP), the products of which are secreted into the plant by the nematode and are required for successful infection. The variability and modular structure of this gene family can lead to the production of a large array of effector proteins. This diversity may allow the nematodes to combat any resistance mechanisms developed by the plant. Each nematode tested within a population is genetically unique in terms of these effector genes. We found huge variation in the number, size and type of HYP effectors at the level of the individual. This may explain some of the difficulties in breeding nematode resistant plants and has profound implications for those working with other plant pathogens.
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Affiliation(s)
- Sebastian Eves-van den Akker
- Centre for Plant Sciences, University of Leeds, Leeds, United Kingdom
- Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Invergowrie, Dundee, United Kingdom
| | | | - John T. Jones
- Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Invergowrie, Dundee, United Kingdom
| | - Peter E. Urwin
- Centre for Plant Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail:
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Nyaku ST, Sripathi VR, Kantety RV, Cseke SB, Buyyarapu R, Mc Ewan R, Gu YQ, Lawrence K, Senwo Z, Sripathi P, George P, Sharma GC. Characterization of the reniform nematode genome by shotgun sequencing. Genome 2014; 57:209-21. [PMID: 25036535 DOI: 10.1139/gen-2014-0019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The reniform nematode (RN), a major agricultural pest particularly on cotton in the United States, is among the major plant-parasitic nematodes for which limited genomic information exists. In this study, over 380 Mb of sequence data were generated from pooled DNA of four adult female RNs and assembled into 67,317 contigs, including 25,904 (38.5%) predicted coding contigs and 41,413 (61.5%) noncoding contigs. Most of the characterized repeats were of low complexity (88.9%), and 0.9% of the contigs matched with 53.2% of GenBank ESTs. The most frequent Gene Ontology (GO) terms for molecular function and biological process were protein binding (32%) and embryonic development (20%). Further analysis showed that 741 (1.1%), 94 (0.1%), and 169 (0.25%) RN genomic contigs matched with 1328 (13.9%), 1480 (5.4%), and 1330 (7.4%) supercontigs of Meloidogyne incognita, Brugia malayi, and Pristionchus pacificus, respectively. Chromosome 5 of Caenorhabditis elegans had the highest number of hits to the RN contigs. Seven putative detoxification genes and three carbohydrate-active enzymes (CAZymes) involved in cell wall degradation were studied in more detail. Additionally, kinases, G protein-coupled receptors, and neuropeptides functioning in physiological, developmental, and regulatory processes were identified in the RN genome.
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Affiliation(s)
- Seloame T Nyaku
- a Department of Biological and Environmental Sciences, Alabama A&M University, Normal, AL 35762, USA
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Ganji S, Jenkins JN, Wubben MJ. Molecular characterization of the reniform nematode C-type lectin gene family reveals a likely role in mitigating environmental stresses during plant parasitism. Gene 2014; 537:269-78. [PMID: 24424511 DOI: 10.1016/j.gene.2013.12.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 11/26/2022]
Abstract
The reniform nematode, Rotylenchulus reniformis, is a damaging semi-endoparasitic pathogen of more than 300 plant species. Transcriptome sequencing of R. reniformis parasitic females revealed an enrichment for sequences homologous to C-type lectins (CTLs), an evolutionarily ancient family of Ca(+2)-dependent carbohydrate-binding proteins that are involved in the innate immune response. To gain further insight as to the potential role of CTLs in facilitating plant parasitism by R. reniformis, we performed a comprehensive assessment of the CTL gene family. 5'- and 3'-RACE experiments identified a total of 11 R. reniformis CTL transcripts (Rr-ctl-1 through Rr-ctl-11) that ranged in length from 1083 to 1,194 bp and showed 93-99% identity with one another. An alignment of cDNA and genomic sequences revealed three introns with the first intron residing within the 5'-untranslated region. BLAST analyses showed the closest homologs belonging to the parasitic nematodes Heligmosomoides polygyrus and Heterodera glycines. Rr-ctl-1, -2, and -3 were expressed throughout the R. reniformis life cycle; whereas, the remaining Rr-ctl genes showed life stage-specific expression. Quantitative real time RT-PCR determined that Rr-ctl transcripts were 839-fold higher in sedentary female nematodes than the next most abundant life stage. Predicted Rr-CTL peptides ranged from 301 to 338 amino acids long, possessed an N-terminal signal peptide for secretion, and contained a conserved CLECT domain, including the mannose-binding motifs EPN and EPD and the conserved WND motif that is required for binding Ca(+2). In addition, Rr-CTL peptides harbored repeats of a novel 17-mer motif within their C-terminus that showed similarity to motifs associated with bacterial ice nucleation proteins. In situ hybridization of Rr-ctl transcripts within sedentary females showed specific accumulation within the hypodermis of the body regions exposed to the soil environment; those structures embedded within the root during parasitism did not show Rr-ctl expression. A phylogenetic analysis of the Rr-CTL CLECT domain with homologous domains from other nematode species suggested that CTLs from animal- and plant-parasitic genera may have evolved in order to play an active role in the parasitic process.
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Affiliation(s)
- Satish Ganji
- Department of Biochemistry and Molecular Biology, Mississippi State University, Mississippi State, MS 39762, USA.
| | - Johnie N Jenkins
- Department of Biochemistry and Molecular Biology, Mississippi State University, Mississippi State, MS 39762, USA; USDA-ARS, Crop Science Research Laboratory, Genetics and Precision Agriculture Research Unit, Mississippi State, MS 39762, USA.
| | - Martin J Wubben
- Department of Biochemistry and Molecular Biology, Mississippi State University, Mississippi State, MS 39762, USA; USDA-ARS, Crop Science Research Laboratory, Genetics and Precision Agriculture Research Unit, Mississippi State, MS 39762, USA.
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9
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Jones JT, Haegeman A, Danchin EGJ, Gaur HS, Helder J, Jones MGK, Kikuchi T, Manzanilla-López R, Palomares-Rius JE, Wesemael WML, Perry RN. Top 10 plant-parasitic nematodes in molecular plant pathology. MOLECULAR PLANT PATHOLOGY 2013; 14:946-61. [PMID: 23809086 PMCID: PMC6638764 DOI: 10.1111/mpp.12057] [Citation(s) in RCA: 794] [Impact Index Per Article: 72.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The aim of this review was to undertake a survey of researchers working with plant-parasitic nematodes in order to determine a 'top 10' list of these pathogens based on scientific and economic importance. Any such list will not be definitive as economic importance will vary depending on the region of the world in which a researcher is based. However, care was taken to include researchers from as many parts of the world as possible when carrying out the survey. The top 10 list emerging from the survey is composed of: (1) root-knot nematodes (Meloidogyne spp.); (2) cyst nematodes (Heterodera and Globodera spp.); (3) root lesion nematodes (Pratylenchus spp.); (4) the burrowing nematode Radopholus similis; (5) Ditylenchus dipsaci; (6) the pine wilt nematode Bursaphelenchus xylophilus; (7) the reniform nematode Rotylenchulus reniformis; (8) Xiphinema index (the only virus vector nematode to make the list); (9) Nacobbus aberrans; and (10) Aphelenchoides besseyi. The biology of each nematode (or nematode group) is reviewed briefly.
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Affiliation(s)
- John T Jones
- James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
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10
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Mitchum MG, Hussey RS, Baum TJ, Wang X, Elling AA, Wubben M, Davis EL. Nematode effector proteins: an emerging paradigm of parasitism. THE NEW PHYTOLOGIST 2013; 199:879-894. [PMID: 23691972 DOI: 10.1111/nph.12323] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/05/2013] [Indexed: 05/18/2023]
Abstract
Phytonematodes use a stylet and secreted effectors to modify host cells and ingest nutrients to support their growth and development. The molecular function of nematode effectors is currently the subject of intense investigation. In this review, we summarize our current understanding of nematode effectors, with a particular focus on proteinaceous stylet-secreted effectors of sedentary endoparasitic phytonematodes, for which a wealth of information has surfaced in the past 10 yr. We provide an update on the effector repertoires of several of the most economically important genera of phytonematodes and discuss current approaches to dissecting their function. Lastly, we highlight the latest breakthroughs in effector discovery that promise to shed new light on effector diversity and function across the phylum Nematoda.
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Affiliation(s)
- Melissa G Mitchum
- Division of Plant Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Richard S Hussey
- Department of Plant Pathology, University of Georgia, Athens, GA, 30602, USA
| | - Thomas J Baum
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA
| | - Xiaohong Wang
- USDA-ARS, Robert W. Holley Center for Agriculture and Health and Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Axel A Elling
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
| | - Martin Wubben
- USDA-ARS, Crop Science Research Laboratory, Genetics and Precision Agriculture Research Unit and Department of Biochemistry and Molecular Biology, Mississippi State University, Mississippi State, MS, 39762, USA
| | - Eric L Davis
- Department of Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
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11
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Showmaker K, Lawrence GW, Lu S, Balbalian C, Klink VP. Quantitative field testing Rotylenchulus reniformis DNA from metagenomic samples isolated directly from soil. PLoS One 2011; 6:e28954. [PMID: 22194958 PMCID: PMC3241691 DOI: 10.1371/journal.pone.0028954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 11/17/2011] [Indexed: 11/19/2022] Open
Abstract
A quantitative PCR procedure targeting the β-tubulin gene determined the number of Rotylenchulus reniformis Linford & Oliveira 1940 in metagenomic DNA samples isolated from soil. Of note, this outcome was in the presence of other soil-dwelling plant parasitic nematodes including its sister genus Helicotylenchus Steiner, 1945. The methodology provides a framework for molecular diagnostics of nematodes from metagenomic DNA isolated directly from soil.
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Affiliation(s)
- Kurt Showmaker
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Gary W. Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Shien Lu
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Clarissa Balbalian
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Bost Extension Center, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Vincent P. Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, Mississippi, United States of America
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12
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Haegeman A, Mantelin S, Jones JT, Gheysen G. Functional roles of effectors of plant-parasitic nematodes. Gene 2011; 492:19-31. [PMID: 22062000 DOI: 10.1016/j.gene.2011.10.040] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/12/2011] [Accepted: 10/20/2011] [Indexed: 11/17/2022]
Abstract
Plant pathogens have evolved a variety of different strategies that allow them to successfully infect their hosts. Plant-parasitic nematodes secrete numerous proteins into their hosts. These proteins, called effectors, have various functions in the plant cell. The most studied effectors to date are the plant cell wall degrading enzymes, which have an interesting evolutionary history since they are believed to have been acquired from bacteria or fungi by horizontal gene transfer. Extensive genome, transcriptome and proteome studies have shown that plant-parasitic nematodes secrete many additional effectors. The function of many of these is less clear although during the last decade, several research groups have determined the function of some of these effectors. Even though many effectors remain to be investigated, it has already become clear that they can have very diverse functions. Some are involved in suppression of plant defences, while others can specifically interact with plant signalling or hormone pathways to promote the formation of nematode feeding sites. In this review, the most recent progress in the understanding of the function of plant-parasitic nematode effectors is discussed.
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Affiliation(s)
- Annelies Haegeman
- Department of Molecular Biotechnology, Ghent University, Coupure links 653, 9000 Ghent, Belgium
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13
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Zhou R, Xia Q, Huang H, Lai M, Wang Z. Construction of a cDNA library from female adult of Toxocara canis, and analysis of EST and immune-related genes expressions. Exp Parasitol 2011; 129:120-6. [PMID: 21767535 DOI: 10.1016/j.exppara.2011.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 05/29/2011] [Accepted: 07/04/2011] [Indexed: 02/05/2023]
Abstract
Toxocara canis is a widespread intestinal nematode parasite of dogs, which can also cause disease in humans. We employed an expressed sequence tag (EST) strategy in order to study gene-expression including development, digestion and reproduction of T. canis. ESTs provided a rapid way to identify genes, particularly in organisms for which we have very little molecular information. In this study, a cDNA library was constructed from a female adult of T. canis and 215 high-quality ESTs from 5'-ends of the cDNA clones representing 79 unigenes were obtained. The titer of the primary cDNA library was 1.83×10(6)pfu/mL with a recombination rate of 99.33%. Most of the sequences ranged from 300 to 900bp with an average length of 656bp. Cluster analysis of these ESTs allowed identification of 79 unique sequences containing 28 contigs and 51 singletons. BLASTX searches revealed that 18 unigenes (22.78% of the total) or 70 ESTs (32.56% of the total) were novel genes that had no significant matches to any protein sequences in the public databases. The rest of the 61 unigenes (77.22% of the total) or 145 ESTs (67.44% of the total) were closely matched to the known genes or sequences deposited in the public databases. These genes were classified into seven groups based on their known or putative biological functions. We also confirmed the gene expression patterns of several immune-related genes using RT-PCR examination. This work will provide a valuable resource for the further investigations in the stage-, sex- and tissue-specific gene transcription or expression.
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Affiliation(s)
- Rongqiong Zhou
- Department of Veterinary Medicine, Rongchang Campus, Southwest University, Chongqing 402460, PR China
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14
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Haegeman A, Joseph S, Gheysen G. Analysis of the transcriptome of the root lesion nematode Pratylenchus coffeae generated by 454 sequencing technology. Mol Biochem Parasitol 2011; 178:7-14. [PMID: 21513748 DOI: 10.1016/j.molbiopara.2011.04.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/30/2011] [Accepted: 04/04/2011] [Indexed: 10/18/2022]
Abstract
To study interactions between plants and plant-parasitic nematodes, several omics studies have nowadays become extremely useful. Since most data available so far is derived from sedentary nematodes, we decided to improve the knowledge on migratory nematodes by studying the transcriptome of the nematode Pratylenchus coffeae through generating expressed sequence tags (ESTs) on a 454 sequencing platform. In this manuscript we present the generation, assembly and annotation of over 325,000 reads from P. coffeae. After assembling these reads, 56,325 contigs and singletons with an average length of 353bp were selected for further analyses. Homology searches revealed that 25% of these sequences had significant matches to the Swiss-prot/trEMBL database and 29% had significant matches in nematode ESTs. Over 10,000 sequences were successfully annotated, corresponding to over 6000 unique Gene Ontology identifiers and 5000 KEGG orthologues. Different approaches led to the identification of different sequences putatively involved in the parasitism process. Several plant cell wall modifying enzymes were identified, including an arabinogalactan galactosidase, so far identified in cyst nematodes only. Additionally, some new putative cell wall modifying enzymes are present belonging to GHF5 and GHF16, although further functional studies are needed to determine the true role of these proteins. Furthermore, a homologue to a chorismate mutase was found, suggesting that this parasitism gene has a wider occurrence in plant-parasitic nematodes than previously assumed. Finally, the dataset was searched for orthologues against the Meloidogyne genomes and genes involved in the RNAi pathway. In conclusion, the generated transcriptome data of P. coffeae will be very useful in the future for several projects: (1) evolutionary studies of specific gene families, such as the plant cell wall modifying enzymes, (2) the identification and functional analysis of candidate effector genes, (3) the development of new control strategies, e.g. by finding new targets for RNAi and (4) the annotation of the upcoming genome sequence.
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Affiliation(s)
- Annelies Haegeman
- Ghent University, Department of Molecular Biotechnology, Ghent, Belgium
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