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Winter MR, Taranto AP, Yimer HZ, Coomer Blundell A, Siddique S, Williamson VM, Lunt DH. Phased chromosome-scale genome assembly of an asexual, allopolyploid root-knot nematode reveals complex subgenomic structure. PLoS One 2024; 19:e0302506. [PMID: 38843263 PMCID: PMC11156385 DOI: 10.1371/journal.pone.0302506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 04/05/2024] [Indexed: 06/09/2024] Open
Abstract
We present the chromosome-scale genome assembly of the allopolyploid root-knot nematode Meloidogyne javanica. We show that the M. javanica genome is predominantly allotetraploid, comprising two subgenomes, A and B, that most likely originated from hybridisation of two ancestral parental species. The assembly was annotated using full-length non-chimeric transcripts, comparison to reference databases, and ab initio prediction techniques, and the subgenomes were phased using ancestral k-mer spectral analysis. Subgenome B appears to show fission of chromosomal contigs, and while there is substantial synteny between subgenomes, we also identified regions lacking synteny that may have diverged in the ancestral genomes prior to or following hybridisation. This annotated and phased genome assembly forms a significant resource for understanding the origins and genetics of these globally important plant pathogens.
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Affiliation(s)
- Michael R. Winter
- School of Natural Sciences, University of Hull, Hull, United Kingdom
| | - Adam P. Taranto
- Department of Plant Pathology, University of California Davis, Davis, CA, United States of America
| | - Henok Zemene Yimer
- Department of Entomology and Nematology, University of California Davis, Davis, CA, United States of America
| | - Alison Coomer Blundell
- Department of Plant Pathology, University of California Davis, Davis, CA, United States of America
| | - Shahid Siddique
- Department of Entomology and Nematology, University of California Davis, Davis, CA, United States of America
| | - Valerie M. Williamson
- Department of Plant Pathology, University of California Davis, Davis, CA, United States of America
| | - David H. Lunt
- School of Natural Sciences, University of Hull, Hull, United Kingdom
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2
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Gibson AK, Mundim FM, Ramirez AL, Timper P. Do biological control agents adapt to local pest genotypes? A multiyear test across geographic scales. Evol Appl 2024; 17:e13682. [PMID: 38617827 PMCID: PMC11009426 DOI: 10.1111/eva.13682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/05/2024] [Accepted: 03/05/2024] [Indexed: 04/16/2024] Open
Abstract
Parasite local adaptation has been a major focus of (co)evolutionary research on host-parasite interactions. Studies of wild host-parasite systems frequently find that parasites paired with local, sympatric host genotypes perform better than parasites paired with allopatric host genotypes. In contrast, there are few such tests in biological control systems to establish whether biological control parasites commonly perform better on sympatric pest genotypes. This knowledge gap prevents the optimal design of biological control programs: strong local adaptation could argue for the use of sympatric parasites to achieve consistent pest control. To address this gap, we tested for local adaptation of the biological control bacterium Pasteuria penetrans to the root-knot nematode Meloidogyne arenaria, a global threat to a wide range of crops. We measured the probability and intensity of P. penetrans infection on sympatric and allopatric M. arenaria over the course of 4 years. Our design accounted for variation in adaptation across scales by conducting tests within and across fields, and we isolated the signature of parasite adaptation by comparing parasites collected over the course of the growing season. Our results are largely inconsistent with local adaptation of P. penetrans to M. arenaria: in 3 of 4 years, parasites performed similarly well in sympatric and allopatric combinations. In 1 year, however, infection probability was 28% higher for parasites paired with hosts from their sympatric plot, relative to parasites paired with hosts from other plots within the same field. These mixed results argue for population genetic data to characterize the scale of gene flow and genetic divergence in this system. Overall, our findings do not provide strong support for using P. penetrans from local fields to enhance biological control of Meloidogyne.
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Affiliation(s)
| | - Fabiane M. Mundim
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
- Department of BiologyUtah State UniversityLoganUtahUSA
| | - Abbey L. Ramirez
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Patricia Timper
- United States Department of Agriculture Agricultural Research ServiceTiftonGeorgiaUSA
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3
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Al-Jawabreh R, Lastik D, McKenzie D, Reynolds K, Suleiman M, Mousley A, Atkinson L, Hunt V. Advancing Strongyloides omics data: bridging the gap with Caenorhabditis elegans. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220437. [PMID: 38008117 PMCID: PMC10676819 DOI: 10.1098/rstb.2022.0437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/31/2023] [Indexed: 11/28/2023] Open
Abstract
Among nematodes, the free-living model organism Caenorhabditis elegans boasts the most advanced portfolio of high-quality omics data. The resources available for parasitic nematodes, including Strongyloides spp., however, are lagging behind. While C. elegans remains the most tractable nematode and has significantly advanced our understanding of many facets of nematode biology, C. elegans is not suitable as a surrogate system for the study of parasitism and it is important that we improve the omics resources available for parasitic nematode species. Here, we review the omics data available for Strongyloides spp. and compare the available resources to those for C. elegans and other parasitic nematodes. The advancements in C. elegans omics offer a blueprint for improving omics-led research in Strongyloides. We suggest areas of priority for future research that will pave the way for expansions in omics resources and technologies. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.
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Affiliation(s)
- Reem Al-Jawabreh
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
| | - Dominika Lastik
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
| | | | - Kieran Reynolds
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
| | - Mona Suleiman
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
| | | | | | - Vicky Hunt
- Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK
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4
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Shigueoka LH, de Batista Fonseca IC, Sera GH, Sera T, Aleandro da Silva S, Dorigo OF, Machado ACZ. Virulence and Reproductive Fitness of Meloidogyne paranaensis Field Populations in Coffee Genotypes. PLANT DISEASE 2022; 106:2618-2624. [PMID: 35442053 DOI: 10.1094/pdis-01-22-0247-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The aim of this study was to characterize Meloidogyne paranaensis populations collected from infested coffee crops. Methodologies used to characterize the 11 studied populations from municipalities in Paraná and Minas Gerais States involved the morphological analysis of perineal patterns, biochemical analysis by isozyme electrophoresis, sequencing of internal transcribes spacer 1 (ITS-1) and D2/D3 ribosomal DNA (rDNA) regions, reproductive fitness, and virulence characterization in coffee genotypes. Morphological evaluations showed the existence of variation between populations, although the majority of them showed typical perineal patterns. The biochemical identification was based on α-esterase isozyme analyses and resulted in the appearance of three distinct profiles: P1 (typical), P2 (atypical), and a nondescribed profile, P2b. BLAST of the ITS-1 and D2/D3 rDNA regions indicated homology (>95%) with other sequences deposited in GenBank. For reproductive fitness and virulence characterization, 13 coffee genotypes (5 Coffea arabica and 8 C. canephora) were inoculated with 11 M. paranaensis populations. Variation in the reproductive fitness of populations was observed for cultivar Mundo Novo, a genotype without resistance genes, and variation in the virulence of populations was observed in genotypes carrying resistance genes. Three populations exhibited virulence combined with high reproductive fitness, while one showed virulence with low reproductive fitness. Some hosts were resistant to 11 populations, while one of the hosts was resistant to only one population, indicating the presence of different resistance genes. Nevertheless, no relationship was observed between the origin of population and their variations in perineal patterns, esterase profiles, phylogeny, or reproductive fitness in coffee genotypes, or between the different characterizations, although differences were observed within each characteristic.
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Affiliation(s)
| | | | - Gustavo Hiroshi Sera
- Instituto de Desenvolvimento Rural do Paraná-IAPAR-EMATER, 86047-902, Londrina, PR, Brazil
| | - Tumoru Sera
- Instituto de Desenvolvimento Rural do Paraná-IAPAR-EMATER, 86047-902, Londrina, PR, Brazil
| | | | - Orazília França Dorigo
- Instituto de Desenvolvimento Rural do Paraná-IAPAR-EMATER, 86047-902, Londrina, PR, Brazil
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5
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Molecular Phylogenetic Characterization of Anguina tritici (Steinbuch, 1799) Filipjev, 1936 (Rhabditida: Anguinidae) on Barley from Iraq. J Nematol 2022; 54:20220040. [PMID: 36338424 PMCID: PMC9583410 DOI: 10.2478/jofnem-2022-0040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Indexed: 11/07/2022] Open
Abstract
During a nematological survey in Iraq, in the Bashika area, Ninevah province, an anguinid nematode population was isolated from galls of infected barley plants. The morphological characteristics indicated that the recovered species is identical to Anguina tritici. The barley population of A. tritici was molecularly characterized by sequencing two ribosomal regions (ITS and 18S rRNA genes), and their phylogenetic analyses revealed the newly generated sequences are in sister relation to corresponding sequences of A. tritici from wheat in the Bayesian tree, providing further evidence that the host plant can contribute to the separation of new isolates of plant parasitic nematodes.
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Rutter WB, Franco J, Gleason C. Rooting Out the Mechanisms of Root-Knot Nematode-Plant Interactions. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:43-76. [PMID: 35316614 DOI: 10.1146/annurev-phyto-021621-120943] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Root-knot nematodes (RKNs; Meloidogyne spp.) engage in complex parasitic interactions with many different host plants around the world, initiating elaborate feeding sites and disrupting host root architecture. Although RKNs have been the focus of research for many decades, new molecular tools have provided useful insights into the biological mechanisms these pests use to infect and manipulate their hosts. From identifying host defense mechanisms underlying resistance to RKNs to characterizing nematode effectors that alter host cellular functions, the past decade of research has significantly expanded our understanding of RKN-plant interactions, and the increasing number of quality parasite and host genomes promises to enhance future research efforts into RKNs. In this review, we have highlighted recent discoveries, summarized the current understanding within the field, and provided links to new and useful resources for researchers. Our goal is to offer insights and tools to support the study of molecular RKN-plant interactions.
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Affiliation(s)
- William B Rutter
- US Vegetable Laboratory, USDA Agricultural Research Service, Charleston, South Carolina, USA
| | - Jessica Franco
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA;
| | - Cynthia Gleason
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA;
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7
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Marquez J, Hajihassani A, Davis RF. Evaluation of summer and winter cover crops for variations in host suitability for Meloidogyne incognita, M. arenaria and M. javanica. NEMATOLOGY 2022. [DOI: 10.1163/15685411-bja10172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Summary
Root-knot nematode (RKN) is an important pathogen on vegetables; therefore, planting a non- or poor host cover crop following a susceptible vegetable crop is a promising management option. This study builds upon previous studies and evaluates the variations in host status of cover crop candidates for reducing the reproduction of RKN populations (Meloidogyne incognita, M. arenaria and M. javanica) in Georgia, USA, to shed light on previous inconsistencies regarding the host status of cover crops and effectiveness in the field. Two glasshouse trials tested the host status of 14 plant species and 18 cultivars plus susceptible tomato ‘Rutgers’. Sixty days after inoculation, roots were evaluated for galling (GI) and egg mass index (EI). Gall formation was not a reliable indication of RKN reproduction for many cover crops, which had higher EI than GI. Based on GI, all cover crops were either non-hosts, ranging from non-hosts to poor hosts or poor hosts to all three RKN species, except blue lupine and hairy vetch, which were susceptible to all three RKN species and had a GI and EI equal to the susceptible tomato control. Based on EI, only bahiagrass, bermudagrass, marigold, millet and velvetbean were either non-hosts or ranged from non-hosts to poor hosts. Eleven cover crops varied in host status to the three RKN species screened, ranging from either non-host to poor hosts or poor hosts to susceptible, which could explain inconsistencies in glasshouse and field trials.
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Affiliation(s)
- Josiah Marquez
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
| | - Abolfazl Hajihassani
- Department of Entomology and Nematology, Fort Lauderdale Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Davie, FL 33314, USA
| | - Richard F. Davis
- Crop Genetics and Breeding Research Unit, United States Department of Agriculture – Agricultural Research Service, Tifton, GA 31793, USA
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8
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Hassanaly-Goulamhoussen R, De Carvalho Augusto R, Marteu-Garello N, Péré A, Favery B, Da Rocha M, Danchin EGJ, Abad P, Grunau C, Perfus-Barbeoch L. Chromatin Landscape Dynamics in the Early Development of the Plant Parasitic Nematode Meloidogyne incognita. Front Cell Dev Biol 2021; 9:765690. [PMID: 34938734 PMCID: PMC8685519 DOI: 10.3389/fcell.2021.765690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/03/2021] [Indexed: 11/17/2022] Open
Abstract
In model organisms, epigenome dynamics underlies a plethora of biological processes. The role of epigenetic modifications in development and parasitism in nematode pests remains unknown. The root-knot nematode Meloidogyne incognita adapts rapidly to unfavorable conditions, despite its asexual reproduction. However, the mechanisms underlying this remarkable plasticity and their potential impact on gene expression remain unknown. This study provides the first insight into contribution of epigenetic mechanisms to this plasticity, by studying histone modifications in M. incognita. The distribution of five histone modifications revealed the existence of strong epigenetic signatures, similar to those found in the model nematode Caenorhabditis elegans. We investigated their impact on chromatin structure and their distribution relative to transposable elements (TE) loci. We assessed the influence of the chromatin landscape on gene expression at two developmental stages: eggs, and pre-parasitic juveniles. H3K4me3 histone modification was strongly correlated with high levels of expression for protein-coding genes implicated in stage-specific processes during M. incognita development. We provided new insights in the dynamic regulation of parasitism genes kept under histone modifications silencing. In this pioneering study, we establish a comprehensive framework for the importance of epigenetic mechanisms in the regulation of the genome expression and its stability in plant-parasitic nematodes.
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Affiliation(s)
| | - Ronaldo De Carvalho Augusto
- IHPE, Univ Perpignan Via Domitia, CNRS, IFREMER, Univ Montpellier, Perpignan, France.,Laboratory of Biology and Modeling of the Cell, Ecole Normale Supérieure de Lyon, CNRS, Université Claude Bernard de Lyon, Université de Lyon, Lyon, France
| | | | - Arthur Péré
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | - Bruno Favery
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | - Martine Da Rocha
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | | | - Pierre Abad
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France
| | - Christoph Grunau
- IHPE, Univ Perpignan Via Domitia, CNRS, IFREMER, Univ Montpellier, Perpignan, France
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9
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Nguyen VC, Khallouk S, Polidori J, Truch J, Portier U, Lafargue M, Tandonnet JP, Ollat N, Van Ghelder C, Banora MY, Esmenjaud D. Evidence of Sexual Reproduction Events in the Dagger Nematode Xiphinema index in Grapevine Resistance Experiments Under Controlled Conditions. PLANT DISEASE 2021; 105:2664-2669. [PMID: 33320044 DOI: 10.1094/pdis-06-20-1409-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The dagger nematode Xiphinema index has a major economic impact because of its transmission of Grapevine fanleaf virus to grapevines. This vector nematode, which was introduced into Western countries from the Middle East together with the domesticated grapevine, mostly reproduces by meiotic parthenogenesis, but microsatellite multilocus genotype (MLG) analysis has revealed the occurrence of rare sexual reproduction events in field conditions. In a previous 6-year study under controlled conditions, we evaluated the durability of resistance to X. index in accessions derived from a muscadine resistance source and reference accessions. In this previous study, we used an equal-proportion mixture of four lines (from Spain, Italy, Greece, and Iran) representative of X. index diversity as the inoculum, and we collected random samples in 3-, 4-, 5-, and 6-year-old vines. Here, we genotyped the individuals from these samples using the MLG technique, and we analyzed the changes in line frequency and the occurrence of sexual reproduction events between lines over time. The nematode lines differed in aggressiveness and hybrids between lines were detected at a low, but apparently increasing rate. Hybridization events were recovered in all accessions, regardless of resistance status and propagation type. Finally, our data provide the first evidence of sexual reproduction in the nematode X. index under controlled conditions.
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Affiliation(s)
- Van Chung Nguyen
- INRAE, Université Côte d'Azur, CNRS, ISA, 06903 Sophia Antipolis, France
| | | | - Joël Polidori
- INRAE, Université Côte d'Azur, CNRS, ISA, 06903 Sophia Antipolis, France
| | - Julia Truch
- INRAE, Université Côte d'Azur, CNRS, ISA, 06903 Sophia Antipolis, France
| | - Ulysse Portier
- INRAE, Université Côte d'Azur, CNRS, ISA, 06903 Sophia Antipolis, France
| | - Maria Lafargue
- EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, 33882 Villenave d'Ornon, France
| | - Jean-Pascal Tandonnet
- EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, 33882 Villenave d'Ornon, France
| | - Nathalie Ollat
- EGFV, Univ. Bordeaux, Bordeaux Sciences Agro, INRAE, ISVV, 33882 Villenave d'Ornon, France
| | - Cyril Van Ghelder
- INRAE, Université Côte d'Azur, CNRS, ISA, 06903 Sophia Antipolis, France
| | - Mohamed Youssef Banora
- Ain Shams University, Faculty of Agriculture, Department of Plant Pathology, 11241 Hadayek Shoubra, Cairo, Egypt
| | - Daniel Esmenjaud
- INRAE, Université Côte d'Azur, CNRS, ISA, 06903 Sophia Antipolis, France
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10
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Kozlowski DKL, Hassanaly‐Goulamhoussen R, Da Rocha M, Koutsovoulos GD, Bailly‐Bechet M, Danchin EGJ. Movements of transposable elements contribute to the genomic plasticity and species diversification in an asexually reproducing nematode pest. Evol Appl 2021; 14:1844-1866. [PMID: 34295368 PMCID: PMC8288018 DOI: 10.1111/eva.13246] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 12/14/2022] Open
Abstract
Despite reproducing without sexual recombination, Meloidogyne incognita is an adaptive and versatile phytoparasitic nematode. This species displays a global distribution, can parasitize a large range of plants, and can overcome plant resistance in a few generations. The mechanisms underlying this adaptability remain poorly known. At the whole-genome level, only a few single nucleotide variations have been observed across different geographical isolates with distinct ranges of compatible hosts. Exploring other factors possibly involved in genomic plasticity is thus important. Transposable elements (TEs), by their repetitive nature and mobility, can passively and actively impact the genome dynamics. This is particularly expected in polyploid hybrid genomes such as the one of M. incognita. Here, we have annotated the TE content of M. incognita, analyzed the statistical properties of this TE landscape, and used whole-genome pool-seq data to estimate the mobility of these TEs across twelve geographical isolates, presenting variations in ranges of compatible host plants. DNA transposons are more abundant than retrotransposons, and the high similarity of TE copies to their consensus sequences suggests they have been at least recently active. We have identified loci in the genome where the frequencies of presence of a TE showed substantial variations across the different isolates. Overall, variations in TE frequencies across isolates followed their phylogenetic divergence, suggesting TEs participate in the species diversification. Compared with the M. incognita reference genome, we detected isolate and lineage-specific de novo insertion of some TEs, including within genic regions or in the upstream regulatory regions. We validated by PCR the insertion of some of these TEs inside genic regions, confirming TE movements have possible functional impacts. Overall, we show DNA transposons can drive genomic plasticity in M. incognita and their role in genome evolution of other parthenogenetic animal deserves further investigation.
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11
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Iqbal S, Jones MGK, Fosu-Nyarko J. RNA interference of an orthologue of Dicer of Meloidogyne incognita alludes to the gene's importance in nematode development. Sci Rep 2021; 11:11156. [PMID: 34045504 PMCID: PMC8160347 DOI: 10.1038/s41598-021-90363-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 05/04/2021] [Indexed: 12/13/2022] Open
Abstract
Dicers and dicer-like enzymes play an essential role in small RNA processing in eukaryotes. Nematodes are thought to encode one dicer, DCR-1; only that for Caenorhabditis spp. is well-characterised. Using genomic sequences of eight root-knot nematodes (Meloidogyne spp.), we identified putative coding sequences typical of eukaryotic DICERS. We noted that the primary and secondary structures of DICERS they encode were different for different Meloidogyne species and even for isolates of the same species, suggesting paralogy for the gene. One of the genes for M. incognita (Midcr-1.1) expressed in eggs, juvenile stage 2 and adults, with the highest expression in the adult females. All the Meloidogyne DICERS had seven major domains typical of those for Caenorhabditis spp. and humans with very similar protein folding. RNAi of Midcr-1.1 in J2s using seven dsRNAs, each based on sequences encoding the domains, induced mild paralysis but measurable knockdown was detected in J2s treated with five of the dsRNAs. For four of the dsRNAs, the RNAi effect lasted and reduced the nematode’s infectivity. Also, host plant delivery of dsRNAs complementary to coding sequences of the Dicer Dimerisation domain impaired development, reducing nematode infection by 71%. These results confirm the importance of the gene to nematode health.
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Affiliation(s)
- Sadia Iqbal
- Crop Biotechnology Research Group, College of Science, Health, Engineering and Education, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, Australia.
| | - Michael G K Jones
- Crop Biotechnology Research Group, College of Science, Health, Engineering and Education, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, Australia
| | - John Fosu-Nyarko
- Crop Biotechnology Research Group, College of Science, Health, Engineering and Education, WA State Agricultural Biotechnology Centre, Murdoch University, Perth, Australia.
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12
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Montarry J, Mimee B, Danchin EGJ, Koutsovoulos GD, Ste-Croix DT, Grenier E. Recent Advances in Population Genomics of Plant-Parasitic Nematodes. PHYTOPATHOLOGY 2021; 111:40-48. [PMID: 33151824 DOI: 10.1094/phyto-09-20-0418-rvw] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plant-parasitic nematodes are a costly burden of crop production. Ubiquitous in nature, phytoparasitic nematodes are associated with nearly every important agricultural crop and represent a significant constraint on global food security. Population genetics is a key discipline in plant nematology to understand aspects of the life strategies of these parasites, in particular their modes of reproduction, geographic origins, evolutionary histories, and dispersion abilities. Advances in high-throughput sequencing technologies have enabled a recent but active effort in genomic analyses of plant-parasitic nematodes. Such genomic approaches applied to multiple populations are providing new insights into the molecular and evolutionary processes that underpin the establishment of these nematodes and into a better understanding of the genetic and mechanistic basis of their pathogenicity and adaptation to their host plants. In this review, we attempt to update information about genome resources and genotyping techniques useful for nematologists who are thinking about initiating population genomics or genome sequencing projects. This review is intended also to foster the development of population genomics in plant-parasitic nematodes through highlighting recent publications that illustrate the potential for this approach to identify novel molecular markers or genes of interest and improve our knowledge of the genome variability, pathogenicity, and evolutionary potential of plant-parasitic nematodes.
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Affiliation(s)
| | - Benjamin Mimee
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, Québec, Canada
| | - Etienne G J Danchin
- Institut Sophia Agrobiotech, Université Côte d'Azur, INRAE, CNRS, Sophia Antipolis, France
| | | | - Dave T Ste-Croix
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, Québec, Canada
| | - Eric Grenier
- IGEPP, INRAE, Institut Agro, Univ Rennes, 35650, Le Rheu, France
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13
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Comparative Genomics Reveals Novel Target Genes towards Specific Control of Plant-Parasitic Nematodes. Genes (Basel) 2020; 11:genes11111347. [PMID: 33202889 PMCID: PMC7696266 DOI: 10.3390/genes11111347] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 11/17/2022] Open
Abstract
Plant-parasitic nematodes cause extensive annual yield losses to worldwide agricultural production. Most cultivated plants have no known resistance against nematodes and the few bearing a resistance gene can be overcome by certain species. Chemical methods that have been deployed to control nematodes have largely been banned from use due to their poor specificity and high toxicity. Hence, there is an urgent need for the development of cleaner and more specific control methods. Recent advances in nematode genomics, including in phytoparasitic species, provide an unprecedented opportunity to identify genes and functions specific to these pests. Using phylogenomics, we compared 61 nematode genomes, including 16 for plant-parasitic species and identified more than 24,000 protein families specific to these parasites. In the genome of Meloidogyne incognita, one of the most devastating plant parasites, we found ca. 10,000 proteins with orthologs restricted only to phytoparasitic species and no further homology in protein databases. Among these phytoparasite-specific proteins, ca. 1000 shared the same properties as known secreted effectors involved in essential parasitic functions. Of these, 68 were novel and showed strong expression during the endophytic phase of the nematode life cycle, based on both RNA-seq and RT-qPCR analyses. Besides effector candidates, transcription-related and neuro-perception functions were enriched in phytoparasite-specific proteins, revealing interesting targets for nematode control methods. This phylogenomics analysis constitutes a unique resource for the further understanding of the genetic basis of nematode adaptation to phytoparasitism and for the development of more efficient control methods.
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Genome assembly and annotation of Meloidogyne enterolobii, an emerging parthenogenetic root-knot nematode. Sci Data 2020; 7:324. [PMID: 33020495 PMCID: PMC7536185 DOI: 10.1038/s41597-020-00666-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 08/27/2020] [Indexed: 11/21/2022] Open
Abstract
Root-knot nematodes (genus Meloidogyne) are plant parasites causing huge economic loss in the agricultural industry and affecting severely numerous developing countries. Control methods against these plant pests are sparse, the preferred one being the deployment of plant cultivars bearing resistance genes against Meloidogyne species. However, M. enterolobii is not controlled by the resistance genes deployed in the crop plants cultivated in Europe. The recent identification of this species in Europe is thus a major concern. Here, we sequenced the genome of M. enterolobii using short and long-read technologies. The genome assembly spans 240 Mbp with contig N50 size of 143 kbp, enabling high-quality annotations of 59,773 coding genes, 4,068 non-coding genes, and 10,944 transposable elements (spanning 8.7% of the genome). We validated the genome size by flow cytometry and the structure, quality and completeness by bioinformatics metrics. This ensemble of resources will fuel future projects aiming at pinpointing the genome singularities, the origin, diversity, and adaptive potential of this emerging plant pest. Measurement(s) | genome • sequence_assembly • sequence feature annotation | Technology Type(s) | DNA sequencing assay • sequence assembly process • sequence annotation | Sample Characteristic - Organism | Meloidogyne enterolobii |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12410363
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Chapuis E, Ali N, Noûs C, Besnard G. Adaptive response to olive cultivation in a generalist parasitic nematode (Meloidogyne javanica). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractCultivated plants usually differ from their wild progenitors in several morphological and/or physiological traits. Their microbe communities might also differ because of adaptation to new conditions related to cultivation. To test this hypothesis, we investigated morphological traits in a parthenogenetic root-knot nematode (Meloidogyne javanica) from natural and agricultural environments. Seventeen populations of M. javanica were sampled on cultivated and wild olives in Morocco, then maintained in controlled conditions for a ‘common garden’ experiment. We estimated the genetic variation based on three traits (stylet size, neck width and body width) by a quantitative genetic design (ten families per population and nine individuals per family were measured), and molecular variation was investigated with a mitochondrial marker to identify the genetic lineages of nematode isolates sampled from wild and cultivated olives. Significant morphological differences were detected between individuals from wild vs. cultivated hosts for the three traits, whereas no phylogenetic clustering was observed among isolates collected on those two hosts. Our results thus suggest an adaptive response of the asexual parasite, possibly related to the deep modification of soil nematode communities between natural olive stands and orchards.
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Affiliation(s)
- Elodie Chapuis
- CBGP, IRD, CIRAD, INRA, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Nadeen Ali
- CBGP, IRD, CIRAD, INRA, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | | | - Guillaume Besnard
- CNRS, UPS, IRD, UMR5174, EDB, Université Toulouse III Paul Sabatier, Toulouse Cedex, France
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Asamizu E, Shirasawa K, Hirakawa H, Iwahori H. Root-knot nematode genetic diversity associated with host compatibility to sweetpotato cultivars. MOLECULAR PLANT PATHOLOGY 2020; 21:1088-1098. [PMID: 32558191 PMCID: PMC7368124 DOI: 10.1111/mpp.12961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/10/2020] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
Plant parasitic root-knot nematodes (RKN) such as Meloidogyne incognita cause significant crop losses worldwide. Although RKN are polyphagous, with wide host ranges, races with differing host compatibilities have evolved. Associations between genotype and infection phenotype in M. incognita have not yet been discovered. In this study, 48 M. incognita isolates were collected from geographically diverse fields in Japan and their genomes sequenced. The isolates exhibited various infection compatibilities to five sweetpotato (SP) cultivars and were assigned to SP races. Genome-wide association analysis identified 743 SNPs affecting gene coding sequences, a large number of which (575) were located on a single 1 Mb region. To examine how this polymorphic region evolved, nucleotide diversity (Pi) was scanned at the whole genome scale. The SNP-rich 1 Mb region exhibited high Pi values and was clearly associated with the SP races. SP1 and 2 races showed high Pi values in this region whereas the Pi values of SP3, 4, and 6 were low. Principal component analysis of isolates from this study and globally collected isolates showed selective divergence in this 1 Mb region. Our results suggest for the first time that the host could be a key determining factor stimulating the genomic divergence of M. incognita.
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Affiliation(s)
- Erika Asamizu
- Faculty of AgricultureRyukoku UniversityOtsuShigaJapan
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Bacterial Community Structure Dynamics in Meloidogyne incognita-Infected Roots and Its Role in Worm-Microbiome Interactions. mSphere 2020; 5:5/4/e00306-20. [PMID: 32669465 PMCID: PMC7364209 DOI: 10.1128/msphere.00306-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Plant parasitic nematodes such as Meloidogyne incognita have a complex life cycle, occurring sequentially in various niches of the root and rhizosphere. They are known to form a range of interactions with bacteria and other microorganisms that can affect their densities and virulence. High-throughput sequencing can reveal these interactions in high temporal and geographic resolutions, although thus far we have only scratched the surface. In this study, we have carried out a longitudinal sampling scheme, repeatedly collecting rhizosphere soil, roots, galls, and second-stage juveniles from 20 plants to provide a high-resolution view of bacterial succession in these niches, using 16S rRNA metabarcoding. Our findings indicate that a structured community develops in the root, in which gall communities diverge from root segments lacking a gall, and that this structure is maintained throughout the crop season. We describe the successional process leading toward this structure, which is driven by interactions with the nematode and later by an increase in bacteria often found in hypoxic and anaerobic environments. We present evidence that this structure may play a role in the nematode's chemotaxis toward uninfected root segments. Finally, we describe the J2 epibiotic microenvironment as ecologically deterministic, in part, due to the active bacterial attraction of second-stage juveniles.IMPORTANCE The study of high-resolution successional processes within tightly linked microniches is rare. Using the power and relatively low cost of metabarcoding, we describe the bacterial succession and community structure in roots infected with root-knot nematodes and in the nematodes themselves. We reveal separate successional processes in galls and adjacent non-gall root sections, which are driven by the nematode's life cycle and the progression of the crop season. With their relatively low genetic diversity, large geographic range, spatially complex life cycle, and the simplified agricultural ecosystems they occupy, root-knot nematodes can serve as a model organism for terrestrial holobiont ecology. This perspective can improve our understanding of the temporal and spatial aspects of biological control efficacy.
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