1
|
Molloy B, Baum T, Eves-van den Akker S. Unlocking the development- and physiology-altering 'effector toolbox' of plant-parasitic nematodes. Trends Parasitol 2023; 39:732-738. [PMID: 37438213 DOI: 10.1016/j.pt.2023.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 07/14/2023]
Abstract
Plant parasites take advantage of host developmental plasticity to elicit profound developmental and physiological changes. In the case of plant-parasitic nematodes (PPNs), these changes can result in the development of new plant organs. Despite the importance of the development- and physiology-altering abilities of these parasites in pathology, research has historically focused on their abilities to suppress immunity. We argue that, given the dramatic changes involved in feeding site establishment, it is entirely possible that development- and physiology-altering abilities of PPNs may, in fact, dominate effector repertoires - highlighting the need for novel high-throughput screens for development- and physiology-altering 'tools'. Uncovering this portion of the nematode 'toolbox' can enable biotechnology, enhance crop protection, and shed light on fundamental host biology itself.
Collapse
Affiliation(s)
- Beth Molloy
- Department of Plant Sciences - Crop Science Centre, University of Cambridge, Cambridge, Cambridgeshire, UK
| | - Thomas Baum
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA, USA
| | | |
Collapse
|
2
|
Nakagami S, Notaguchi M, Kondo T, Okamoto S, Ida T, Sato Y, Higashiyama T, Tsai AYL, Ishida T, Sawa S. Root-knot nematode modulates plant CLE3-CLV1 signaling as a long-distance signal for successful infection. SCIENCE ADVANCES 2023; 9:eadf4803. [PMID: 37267361 PMCID: PMC10413670 DOI: 10.1126/sciadv.adf4803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 04/28/2023] [Indexed: 06/04/2023]
Abstract
Plants use many long-distance and systemic signals to modulate growth and development, as well as respond to biotic and abiotic stresses. Parasitic nematodes infect host plant roots and cause severe damage to crop plants. However, the molecular mechanisms that regulate parasitic nematode infections are still unknown. Here, we show that plant parasitic root-knot nematodes (RKNs), Meloidogyne incognita, modulate the host CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE)-CLV1 signaling module to promote the infection progression. Plants deficient in the CLE signaling pathway show enhanced RKN resistance, whereas CLE overexpression leads to increased susceptibility toward RKN. Grafting analysis shows that CLV1 expression in the shoot alone is sufficient to positively regulate RKN infection. Together with results from the split-root culture system, infection assays, and CLE3-CLV1 binding assays, we conclude that mobile root-derived CLE signals are perceived by CLV1 in the shoot, which subsequently produce systemic signals to promote gall formation and RKN reproduction.
Collapse
Affiliation(s)
- Satoru Nakagami
- Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
| | - Michitaka Notaguchi
- Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan
| | - Tatsuhiko Kondo
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Satoru Okamoto
- Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Saitama, 332-0012, Japan
| | - Takanori Ida
- Department of Bioactive Peptides, Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Yoshikatsu Sato
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya 464-8601, Japan
| | - Tetsuya Higashiyama
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Allen Yi-Lun Tsai
- Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
- International Research Center for Agricultural & Environmental Biology, Kumamoto University, Kumamoto 860-8555, Japan
| | - Takashi Ishida
- Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
- International Research Organization for Advanced Science and Technology (IROAST), Kumamoto University, Kumamoto 860-8555, Japan
| | - Shinichiro Sawa
- Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
- International Research Center for Agricultural & Environmental Biology, Kumamoto University, Kumamoto 860-8555, Japan
- International Research Organization for Advanced Science and Technology (IROAST), Kumamoto University, Kumamoto 860-8555, Japan
- Institute of Industrial Nanomaterial (IINA), Kumamoto University, Kumamoto 860-8555, Japan
| |
Collapse
|
3
|
Macharia TN, Duong TA, Moleleki LN. In silico secretome analyses of the polyphagous root-knot nematode Meloidogyne javanica: a resource for studying M. javanica secreted proteins. BMC Genomics 2023; 24:296. [PMID: 37264326 DOI: 10.1186/s12864-023-09366-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 05/07/2023] [Indexed: 06/03/2023] Open
Abstract
BACKGROUND Plant-parasitic nematodes (PPNs) that cause most damage include root-knot nematodes (RKNs) which are a major impediment to crop production. Root-knot nematodes, like other parasites, secrete proteins which are required for parasite proliferation and survival within the host during the infection process. RESULTS Here, we used various computational tools to predict and identify classically and non-classically secreted proteins encoded in the Meloidogyne javanica genome. Furthermore, functional annotation analysis was performed using various integrated bioinformatic tools to determine the biological significance of the predicted secretome. In total, 7,458 proteins were identified as secreted ones. A large percentage of this secretome is comprised of small proteins of ≤ 300 aa sequence length. Functional analyses showed that M. javanica secretome comprises cell wall degrading enzymes for facilitating nematode invasion, and migration by disintegrating the complex plant cell wall components. In addition, peptidases and peptidase inhibitors are an important category of M. javanica secretome involved in compatible host-nematode interactions. CONCLUSION This study identifies the putative secretome encoded in the M. javanica genome. Future experimental validation analyses can greatly benefit from this global analysis of M. javanica secretome. Equally, our analyses will advance knowledge of the interaction between plants and nematodes.
Collapse
Affiliation(s)
- Teresia Nyambura Macharia
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Tuan A Duong
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Lucy Novungayo Moleleki
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.
| |
Collapse
|
4
|
van Steenbrugge JJM, van den Elsen S, Holterman M, Lozano‐Torres J, Putker V, Thorpe P, Goverse A, Sterken M, Smant G, Helder J. Comparative genomics among cyst nematodes reveals distinct evolutionary histories among effector families and an irregular distribution of effector-associated promoter motifs. Mol Ecol 2023; 32:1515-1529. [PMID: 35560992 PMCID: PMC10946958 DOI: 10.1111/mec.16505] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 04/26/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022]
Abstract
Potato cyst nematodes (PCNs), an umbrella term used for two species, Globodera pallida and G. rostochiensis, belong worldwide to the most harmful pathogens of potato. Pathotype-specific host plant resistances are essential for PCN control. However, the poor delineation of G. pallida pathotypes has hampered the efficient use of available host plant resistances. Long-read sequencing technology allowed us to generate a new reference genome of G. pallida population D383 and, as compared to the current reference, the new genome assembly is 42 times less fragmented. For comparison of diversification patterns of six effector families between G. pallida and G. rostochiensis, an additional reference genome was generated for an outgroup, the beet cyst nematode Heterodera schachtii (IRS population). Large evolutionary contrasts in effector family topologies were observed. While VAPs (venom allergen-like proteins) diversified before the split between the three cyst nematode species, the families GLAND5 and GLAND13 only expanded in PCNs after their separation from the genus Heterodera. Although DNA motifs in the promoter regions thought to be involved in the orchestration of effector expression ("DOG boxes") were present in all three cyst nematode species, their presence is not a necessity for dorsal gland-produced effectors. Notably, DOG box dosage was only loosely correlated with the expression level of individual effector variants. Comparison of the G. pallida genome with those of two other cyst nematodes underlined the fundamental differences in evolutionary history between effector families. Resequencing of PCN populations with different virulence characteristics will allow for the linking of these characteristics to the composition of the effector repertoire as well as for the mapping of PCN diversification patterns resulting from extreme anthropogenic range expansion.
Collapse
Affiliation(s)
| | - Sven van den Elsen
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
| | - Martijn Holterman
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
- SolyntaWageningenThe Netherlands
| | | | - Vera Putker
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
| | - Peter Thorpe
- School of Medicine, Medical & Biological SciencesUniversity of St. AndrewsSt AndrewsUK
| | - Aska Goverse
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
| | - Mark G. Sterken
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
| | - Geert Smant
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
| | - Johannes Helder
- Laboratory of NematologyWageningen University & ResearchWageningenThe Netherlands
| |
Collapse
|
5
|
Abstract
Peptide signaling is an emerging paradigm in molecular plant-microbe interactions with vast implications for our understanding of plant-nematode interactions and beyond. Plant-like peptide hormones, first discovered in cyst nematodes, are now recognized as an important class of peptide effectors mediating several different types of pathogenic and symbiotic interactions. Here, we summarize what has been learned about nematode-secreted CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) peptide effectors since the last comprehensive review on this topic a decade ago. We also highlight new discoveries of a diverse array of peptide effectors that go beyond the CLE peptide effector family in not only phytonematodes but in organisms beyond the phylum Nematoda.
Collapse
Affiliation(s)
- Melissa G Mitchum
- Department of Plant Pathology and Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Athens, Georgia, USA; ,
| | - Xunliang Liu
- Department of Plant Pathology and Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Athens, Georgia, USA; ,
| |
Collapse
|
6
|
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.
Collapse
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;
| |
Collapse
|
7
|
Dodueva IE, Lebedeva MA, Lutova LA. Phytopathogens and Molecular Mimicry. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422060035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
8
|
Baidoo R, Yan G. Developing a Real-Time PCR Assay for Direct Identification and Quantification of Soybean Cyst Nematode, Heterodera glycines, in Soil and Its Discrimination from Sugar Beet Cyst Nematode, Heterodera schachtii. PLANT DISEASE 2021; 105:3848-3857. [PMID: 34282930 DOI: 10.1094/pdis-01-21-0129-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The soybean cyst nematode (SCN) Heterodera glycines continues to be a major threat to soybean production worldwide. Morphological discrimination between SCN and other nematodes of the Heterodera schachtii sensu stricto group is not only difficult and time-consuming but also requires high expertise in nematode taxonomy. Molecular assays were developed to differentiate SCN from sugar beet cyst nematode (SBCN) and other nematodes and to quantify SCN directly from DNA extracts of field soils. SCN- and SBCN-specific quantitative real-time PCR (qPCR) primers were designed from a nematode-secreted CLAVATA gene and used for these assays. The primers were evaluated on the basis of target specificity to SCN or SBCN using DNA from 20 isolates of SCN and 32 isolates of other plant-parasitic nematodes. A standard curve relating threshold cycle and log values of nematode numbers was generated from artificially infested soils and was used to quantify SCN in naturally infested field soils. There was a high correlation between the SCN numbers estimated from naturally infested field soils by conventional methods, and the numbers quantified using the SYBR Green I-based qPCR assay. The qPCR assay is highly specific and sensitive and provides improved SCN detection sensitivity down to 1 SCN egg in 20 g of soil (10 eggs/200 g soil). This assay is useful for efficient detection and quantification of SCN directly from field soil. Species-specific conventional PCR assays were also developed each for SCN and SBCN, alongside a qPCR assay that simultaneously discriminates SCN from SBCN. These assays require no expertise in nematode taxonomy and morphology, and they may serve as useful diagnostic tools in research, diagnostic laboratories, and extension services for SCN management. Sensitive and accurate detection and quantification of SCN are essential for recommending effective management measures against SCN. We also investigated the impact of soil texture and nematode life stage on molecular quantification of SCN.
Collapse
Affiliation(s)
| | - Guiping Yan
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108
| |
Collapse
|
9
|
Dodueva I, Lebedeva M, Lutova L. Dialog between Kingdoms: Enemies, Allies and Peptide Phytohormones. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112243. [PMID: 34834606 PMCID: PMC8618561 DOI: 10.3390/plants10112243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 05/14/2023]
Abstract
Various plant hormones can integrate developmental and environmental responses, acting in a complex network, which allows plants to adjust their developmental processes to changing environments. In particular, plant peptide hormones regulate various aspects of plant growth and development as well as the response to environmental stress and the interaction of plants with their pathogens and symbionts. Various plant-interacting organisms, e.g., bacterial and fungal pathogens, plant-parasitic nematodes, as well as symbiotic and plant-beneficial bacteria and fungi, are able to manipulate phytohormonal level and/or signaling in the host plant in order to overcome plant immunity and to create the habitat and food source inside the plant body. The most striking example of such phytohormonal mimicry is the ability of certain plant pathogens and symbionts to produce peptide phytohormones of different classes. To date, in the genomes of plant-interacting bacteria, fungi, and nematodes, the genes encoding effectors which mimic seven classes of peptide phytohormones have been found. For some of these effectors, the interaction with plant receptors for peptide hormones and the effect on plant development and defense have been demonstrated. In this review, we focus on the currently described classes of peptide phytohormones found among the representatives of other kingdoms, as well as mechanisms of their action and possible evolutional origin.
Collapse
|
10
|
Favery B, Dubreuil G, Chen MS, Giron D, Abad P. Gall-Inducing Parasites: Convergent and Conserved Strategies of Plant Manipulation by Insects and Nematodes. ANNUAL REVIEW OF PHYTOPATHOLOGY 2020; 58:1-22. [PMID: 32853101 DOI: 10.1146/annurev-phyto-010820-012722] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Gall-inducing insects and nematodes engage in sophisticated interactions with their host plants. These parasites can induce major morphological and physiological changes in host roots, leaves, and other tissues. Sedentary endoparasitic nematodes, root-knot and cyst nematodes in particular, as well as gall-inducing and leaf-mining insects, manipulate plant development to form unique organs that provide them with food from feeding cells. Sometimes, infected tissues may undergo a developmental switch resulting in the formation of aberrant and spectacular structures (clubs or galls). We describe here the complex interactions between these plant-reprogramming sedentary endoparasites and their infected hosts, focusing on similarities between strategies of plant manipulation. We highlight progress in our understanding of the host plant response to infection and focus on the nematode and insect molecules secreted in planta. We suggest thatlooking at similarities may identify convergent and conserved strategies and shed light on the promise they hold for the development of new management strategies in agriculture and forestry.
Collapse
Affiliation(s)
- Bruno Favery
- INRAE, CNRS, Université Côte d'Azur, ISA, F-06600 Sophia-Antipolis, France;
| | - Géraldine Dubreuil
- Institut de Recherche sur la Biologie de l'Insecte, CNRS, Université de Tours, UMR 7261, 37200 Tours, France;
| | - Ming-Shun Chen
- USDA-ARS and Department of Entomology, Kansas State University, Manhattan, Kansas 66506, USA
| | - David Giron
- Institut de Recherche sur la Biologie de l'Insecte, CNRS, Université de Tours, UMR 7261, 37200 Tours, France;
| | - Pierre Abad
- INRAE, CNRS, Université Côte d'Azur, ISA, F-06600 Sophia-Antipolis, France;
| |
Collapse
|
11
|
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.
Collapse
Affiliation(s)
- Erika Asamizu
- Faculty of AgricultureRyukoku UniversityOtsuShigaJapan
| | | | | | | |
Collapse
|
12
|
Dodueva IE, Lebedeva MA, Kuznetsova KA, Gancheva MS, Paponova SS, Lutova LL. Plant tumors: a hundred years of study. PLANTA 2020; 251:82. [PMID: 32189080 DOI: 10.1007/s00425-020-03375-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/11/2020] [Indexed: 05/21/2023]
Abstract
The review provides information on the mechanisms underlying the development of spontaneous and pathogen-induced tumors in higher plants. The activation of meristem-specific regulators in plant tumors of various origins suggests the meristem-like nature of abnormal plant hyperplasia. Plant tumor formation has more than a century of research history. The study of this phenomenon has led to a number of important discoveries, including the development of the Agrobacterium-mediated transformation technique and the discovery of horizontal gene transfer from bacteria to plants. There are two main groups of plant tumors: pathogen-induced tumors (e.g., tumors induced by bacteria, viruses, fungi, insects, etc.), and spontaneous ones, which are formed in the absence of any pathogen in plants with certain genotypes (e.g., interspecific hybrids, inbred lines, and mutants). The causes of the transition of plant cells to tumor growth are different from those in animals, and they include the disturbance of phytohormonal balance and the acquisition of meristematic characteristics by differentiated cells. The aim of this review is to discuss the mechanisms underlying the development of most known examples of plant tumors.
Collapse
Affiliation(s)
- Irina E Dodueva
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia.
| | - Maria A Lebedeva
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Kseniya A Kuznetsova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Maria S Gancheva
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Svetlana S Paponova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Ludmila L Lutova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| |
Collapse
|
13
|
Olsson V, Joos L, Zhu S, Gevaert K, Butenko MA, De Smet I. Look Closely, the Beautiful May Be Small: Precursor-Derived Peptides in Plants. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:153-186. [PMID: 30525926 DOI: 10.1146/annurev-arplant-042817-040413] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
During the past decade, a flurry of research focusing on the role of peptides as short- and long-distance signaling molecules in plant cell communication has been undertaken. Here, we focus on peptides derived from nonfunctional precursors, and we address several key questions regarding peptide signaling. We provide an overview of the regulatory steps involved in producing a biologically active peptide ligand that can bind its corresponding receptor(s) and discuss how this binding and subsequent activation lead to specific cellular outputs. We discuss different experimental approaches that can be used to match peptide ligands with their receptors. Lastly, we explore how peptides evolved from basic signaling units regulating essential processes in plants to more complex signaling systems as new adaptive traits developed and how nonplant organisms exploit this signaling machinery by producing peptide mimics.
Collapse
Affiliation(s)
- Vilde Olsson
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway;
| | - Lisa Joos
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium;
- VIB-UGent Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Shanshuo Zhu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium;
- VIB-UGent Center for Plant Systems Biology, 9052 Ghent, Belgium
- VIB-UGent Center for Medical Biotechnology, 9000 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, 9000 Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium
| | - Melinka A Butenko
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, 0316 Oslo, Norway;
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium;
- VIB-UGent Center for Plant Systems Biology, 9052 Ghent, Belgium
| |
Collapse
|
14
|
Kim J, Yang R, Chang C, Park Y, Tucker ML. The root-knot nematode Meloidogyne incognita produces a functional mimic of the Arabidopsis INFLORESCENCE DEFICIENT IN ABSCISSION signaling peptide. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3009-3021. [PMID: 29648636 PMCID: PMC5972575 DOI: 10.1093/jxb/ery135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 03/27/2018] [Indexed: 05/12/2023]
Abstract
INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) is a signaling peptide that regulates cell separation in Arabidopsis including floral organ abscission and lateral root emergence. IDA is highly conserved in dicotyledonous flowering plant genomes. IDA-like sequences were also found in the genomic sequences of root-knot nematodes, Meloidogyne spp., which are globally deleterious pathogens of agriculturally important plants, but the role of these genes is unknown. Exogenous treatment of the Arabidopsis ida mutant with synthetic peptide identical to the M. incognita IDA-like 1 (MiIDL1) protein sequence minus its N-terminal signal peptide recovered both the abscission and root architecture defects. Constitutive expression of the full-length MiIDL1 open reading frame in the ida mutant substantially recovered the delayed floral organ abscission phenotype whereas transformants expressing a construct missing the MiIDL1 signal peptide retained the delayed abscission phenotype. Importantly, wild-type Arabidopsis plants harboring an MiIDL1-RNAi construct and infected with nematodes had approximately 40% fewer galls per root than control plants. Thus, the MiIDL1 gene produces a functional IDA mimic that appears to play a role in successful gall development on Arabidopsis roots.
Collapse
Affiliation(s)
- Joonyup Kim
- Soybean Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD, USA
- Department of Cell Biology and Molecular Genetics, Bioscience Research Bldg, University of Maryland, MD, USA
- Life and Industry Convergence Research Institute, Department of Horticulture Bioscience, Pusan National University, Miryang, Republic of Korea
| | - Ronghui Yang
- Soybean Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD, USA
| | - Caren Chang
- Department of Cell Biology and Molecular Genetics, Bioscience Research Bldg, University of Maryland, MD, USA
| | - Younghoon Park
- Life and Industry Convergence Research Institute, Department of Horticulture Bioscience, Pusan National University, Miryang, Republic of Korea
| | - Mark L Tucker
- Soybean Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD, USA
- Correspondence:
| |
Collapse
|
15
|
Smant G, Helder J, Goverse A. Parallel adaptations and common host cell responses enabling feeding of obligate and facultative plant parasitic nematodes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:686-702. [PMID: 29277939 DOI: 10.1111/tpj.13811] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 12/10/2017] [Accepted: 12/14/2017] [Indexed: 05/08/2023]
Abstract
Parallel adaptations enabling the use of plant cells as the primary food source have occurred multiple times in distinct nematode clades. The hallmark of all extant obligate and facultative plant-feeding nematodes is the presence of an oral stylet, which is required for penetration of plant cell walls, delivery of pharyngeal gland secretions into host cells and selective uptake of plant assimilates. Plant parasites from different clades, and even within a single clade, display a large diversity in feeding behaviours ranging from short feeding cycles on single cells to prolonged feeding on highly sophisticated host cell complexes. Despite these differences, feeding of nematodes frequently (but certainly not always) induces common responses in host cells (e.g. endopolyploidization and cellular hypertrophy). It is thought that these host cell responses are brought about by the interplay of effectors and other biological active compounds in stylet secretions of feeding nematodes, but this has only been studied for the most advanced sedentary plant parasites. In fact, these responses are thought to be fundamental for prolonged feeding of sedentary plant parasites on host cells. However, as we discuss in this review, some of these common plant responses to independent lineages of plant parasitic nematodes might also be generic reactions to cell stress and as such their onset may not require specific inputs from plant parasitic nematodes. Sedentary plant parasitic nematodes may utilize effectors and their ability to synthesize other biologically active compounds to tailor these common responses for prolonged feeding on host cells.
Collapse
Affiliation(s)
- Geert Smant
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
| | - Johannes Helder
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
| | - Aska Goverse
- Laboratory of Nematology, Wageningen University, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
| |
Collapse
|
16
|
Goad DM, Zhu C, Kellogg EA. Comprehensive identification and clustering of CLV3/ESR-related (CLE) genes in plants finds groups with potentially shared function. THE NEW PHYTOLOGIST 2017; 216:605-616. [PMID: 27911469 DOI: 10.1111/nph.14348] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/14/2016] [Indexed: 05/06/2023]
Abstract
CLV3/ESR (CLE) proteins are important signaling peptides in plants. The short CLE peptide (12-13 amino acids) is cleaved from a larger pre-propeptide and functions as an extracellular ligand. The CLE family is large and has resisted attempts at classification because the CLE domain is too short for reliable phylogenetic analysis and the pre-propeptide is too variable. We used a model-based search for CLE domains from 57 plant genomes and used the entire pre-propeptide for comprehensive clustering analysis. In total, 1628 CLE genes were identified in land plants, with none recognizable from green algae. These CLEs form 12 groups within which CLE domains are largely conserved and pre-propeptides can be aligned. Most clusters contain sequences from monocots, eudicots and Amborella trichopoda, with sequences from Picea abies, Selaginella moellendorffii and Physcomitrella patens scattered in some clusters. We easily identified previously known clusters involved in vascular differentiation and nodulation. In addition, we found a number of discrete groups whose function remains poorly characterized. Available data indicate that CLE proteins within a cluster are likely to share function, whereas those from different clusters play at least partially different roles. Our analysis provides a foundation for future evolutionary and functional studies.
Collapse
Affiliation(s)
- David M Goad
- Department of Biology, Washington University in St Louis, One Brookings Drive, St Louis, MO, 63130, USA
- Donald Danforth Plant Science Center, 975 North Warson Rd, St Louis, MO, 63132, USA
| | - Chuanmei Zhu
- Donald Danforth Plant Science Center, 975 North Warson Rd, St Louis, MO, 63132, USA
| | - Elizabeth A Kellogg
- Donald Danforth Plant Science Center, 975 North Warson Rd, St Louis, MO, 63132, USA
| |
Collapse
|
17
|
Kikuchi T, Eves-van den Akker S, Jones JT. Genome Evolution of Plant-Parasitic Nematodes. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:333-354. [PMID: 28590877 DOI: 10.1146/annurev-phyto-080516-035434] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Plant parasitism has evolved independently on at least four separate occasions in the phylum Nematoda. The application of next-generation sequencing (NGS) to plant-parasitic nematodes has allowed a wide range of genome- or transcriptome-level comparisons, and these have identified genome adaptations that enable parasitism of plants. Current genome data suggest that horizontal gene transfer, gene family expansions, evolution of new genes that mediate interactions with the host, and parasitism-specific gene regulation are important adaptations that allow nematodes to parasitize plants. Sequencing of a larger number of nematode genomes, including plant parasites that show different modes of parasitism or that have evolved in currently unsampled clades, and using free-living taxa as comparators would allow more detailed analysis and a better understanding of the organization of key genes within the genomes. This would facilitate a more complete understanding of the way in which parasitism has shaped the genomes of plant-parasitic nematodes.
Collapse
Affiliation(s)
- Taisei Kikuchi
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan;
| | - Sebastian Eves-van den Akker
- Division of Plant Sciences, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, United Kingdom
- Department of Biological Chemistry, The John Innes Centre, Norwich, NR4 7UH, United Kingdom
| | - John T Jones
- Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Invergowrie, Dundee, DD2 5DA, United Kingdom
- School of Biology, University of St. Andrews, North Haugh, St. Andrews, KY16 9TZ, United Kingdom
| |
Collapse
|
18
|
Mantelin S, Bellafiore S, Kyndt T. Meloidogyne graminicola: a major threat to rice agriculture. MOLECULAR PLANT PATHOLOGY 2017; 18:3-15. [PMID: 26950515 PMCID: PMC6638252 DOI: 10.1111/mpp.12394] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
TAXONOMY Superkingdom Eukaryota; Kingdom Metazoa; Phylum Nematoda; Class Chromadorea; Order Tylenchida; Suborder Tylenchina; Infraorder Tylenchomorpha; Superfamily Tylenchoidea; Family Meloidogynidae; Subfamily Meloidogyninae; Genus Meloidogyne. BIOLOGY Microscopic non-segmented roundworm. Plant pathogen; obligate sedentary endoparasitic root-knot nematode. Reproduction: facultative meiotic parthenogenetic species in which amphimixis can occur at a low frequency (c. 0.5%); relatively fast life cycle completed in 19-27 days on rice depending on the temperature range. HOST RANGE Reported to infect over 100 plant species, including cereals and grass plants, as well as dicotyledonous plants. Main host: rice (Oryza sativa). SYMPTOMS Characteristic hook-shaped galls (root swellings), mainly formed at the root tips of infected plants. Alteration of the root vascular system causes disruption of water and nutrient transport, stunting, chlorosis and loss of vigour, resulting in poor growth and reproduction of the plants with substantial yield losses in crops. DISEASE CONTROL Nematicides, chemical priming, constant immersion of rice in irrigated fields, crop rotation with resistant or non-host plants, use of nematode-free planting material. Some sources of resistance to Meloidogyne graminicola have been identified in African rice species (O. glaberrima and O. longistaminata), as well as in a few Asian rice cultivars. AGRONOMIC IMPORTANCE Major threat to rice agriculture, particularly in Asia. Adapted to flooded conditions, Meloidogyne graminicola causes problems in all types of rice agrosystems.
Collapse
Affiliation(s)
- Sophie Mantelin
- The James Hutton Institute, Dundee Effector ConsortiumInvergowrieDundeeDD2 5DAUK
| | - Stéphane Bellafiore
- IRD‐CIRAD‐Université Montpellier II, UMR Interactions Plantes Microorganismes Environnement (IPME)34394MontpellierFrance
- LMI‐RICEHanoiVietnam
| | - Tina Kyndt
- Department of Molecular BiotechnologyGhent University9000GhentBelgium
| |
Collapse
|
19
|
Petitot AS, Dereeper A, Agbessi M, Da Silva C, Guy J, Ardisson M, Fernandez D. Dual RNA-seq reveals Meloidogyne graminicola transcriptome and candidate effectors during the interaction with rice plants. MOLECULAR PLANT PATHOLOGY 2016; 17:860-74. [PMID: 26610268 PMCID: PMC6638361 DOI: 10.1111/mpp.12334] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 10/09/2015] [Accepted: 10/09/2015] [Indexed: 05/15/2023]
Abstract
Root-knot nematodes secrete proteinaceous effectors into plant tissues to facilitate infection by suppressing host defences and reprogramming the host metabolism to their benefit. Meloidogyne graminicola is a major pest of rice (Oryza sativa) in Asia and Latin America, causing important crop losses. The goal of this study was to identify M. graminicola pathogenicity genes expressed during the plant-nematode interaction. Using the dual RNA-sequencing (RNA-seq) strategy, we generated transcriptomic data of M. graminicola samples covering the pre-parasitic J2 stage and five parasitic stages in rice plants, from the parasitic J2 to the adult female. In the absence of a reference genome, a de novo M. graminicola transcriptome of 66 396 contigs was obtained from those reads that were not mapped on the rice genome. Gene expression profiling across the M. graminicola life cycle revealed key genes involved in nematode development and provided insights into the genes putatively associated with parasitism. The development of a 'secreted protein prediction' pipeline revealed a typical set of proteins secreted by nematodes, as well as a large number of cysteine-rich proteins and putative nuclear proteins. Combined with expression data, this pipeline enabled the identification of 15 putative effector genes, including two homologues of well-characterized effectors from cyst nematodes (CLE-like and VAP1) and a metallothionein. The localization of gene expression was assessed by in situ hybridization for a subset of candidates. All of these data represent important molecular resources for the elucidation of M. graminicola biology and for the selection of potential targets for the development of novel control strategies for this nematode species.
Collapse
Affiliation(s)
- Anne-Sophie Petitot
- IRD, UMR IRD-Cirad-UM2 Interactions Plantes-Microbes-Environnement, 34394, Montpellier Cedex 5, France
| | - Alexis Dereeper
- IRD, UMR IRD-Cirad-UM2 Interactions Plantes-Microbes-Environnement, 34394, Montpellier Cedex 5, France
| | - Mawusse Agbessi
- IRD, UMR IRD-Cirad-UM2 Interactions Plantes-Microbes-Environnement, 34394, Montpellier Cedex 5, France
| | - Corinne Da Silva
- CEA, Institut de Génomique, GENOSCOPE - Centre National de Séquençage, 91057, Evry Cedex, France
| | - Julie Guy
- CEA, Institut de Génomique, GENOSCOPE - Centre National de Séquençage, 91057, Evry Cedex, France
| | - Morgane Ardisson
- INRA, UMR Amélioration Génétique et Adaptation des Plantes, 34060, Montpellier Cedex 1, France
| | - Diana Fernandez
- IRD, UMR IRD-Cirad-UM2 Interactions Plantes-Microbes-Environnement, 34394, Montpellier Cedex 5, France
| |
Collapse
|
20
|
Favery B, Quentin M, Jaubert-Possamai S, Abad P. Gall-forming root-knot nematodes hijack key plant cellular functions to induce multinucleate and hypertrophied feeding cells. JOURNAL OF INSECT PHYSIOLOGY 2016. [PMID: 26211599 DOI: 10.1016/j.jinsphys.2015.07.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Among plant-parasitic nematodes, the root-knot nematodes (RKNs) of the Meloidogyne spp. are the most economically important genus. RKN are root parasitic worms able to infect nearly all crop species and have a wide geographic distribution. During infection, RKNs establish and maintain an intimate relationship with the host plant. This includes the creation of a specialized nutritional structure composed of multinucleate and hypertrophied giant cells, which result from the redifferentiation of vascular root cells. Giant cells constitute the sole source of nutrients for the nematode and are essential for growth and reproduction. Hyperplasia of surrounding root cells leads to the formation of the gall or root-knot, an easily recognized symptom of plant infection by RKNs. Secreted effectors produced in nematode salivary glands and injected into plant cells through a specialized feeding structure called the stylet play a critical role in the formation of giant cells. Here, we describe the complex interactions between RKNs and their host plants. We highlight progress in understanding host plant responses, focusing on how RKNs manipulate key plant processes and functions, including cell cycle, defence, hormones, cellular scaffold, metabolism and transport.
Collapse
Affiliation(s)
- Bruno Favery
- INRA, UMR 1355 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; Univ. Nice Sophia Antipolis, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; CNRS, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France
| | - Michaël Quentin
- INRA, UMR 1355 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; Univ. Nice Sophia Antipolis, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; CNRS, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France
| | - Stéphanie Jaubert-Possamai
- INRA, UMR 1355 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; Univ. Nice Sophia Antipolis, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; CNRS, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France
| | - Pierre Abad
- INRA, UMR 1355 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; Univ. Nice Sophia Antipolis, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France; CNRS, UMR 7254 Institut Sophia Agrobiotech, 06900 Sophia-Antipolis, France.
| |
Collapse
|
21
|
Mesarich CH, Bowen JK, Hamiaux C, Templeton MD. Repeat-containing protein effectors of plant-associated organisms. FRONTIERS IN PLANT SCIENCE 2015; 6:872. [PMID: 26557126 PMCID: PMC4617103 DOI: 10.3389/fpls.2015.00872] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/01/2015] [Indexed: 05/10/2023]
Abstract
Many plant-associated organisms, including microbes, nematodes, and insects, deliver effector proteins into the apoplast, vascular tissue, or cell cytoplasm of their prospective hosts. These effectors function to promote colonization, typically by altering host physiology or by modulating host immune responses. The same effectors however, can also trigger host immunity in the presence of cognate host immune receptor proteins, and thus prevent colonization. To circumvent effector-triggered immunity, or to further enhance host colonization, plant-associated organisms often rely on adaptive effector evolution. In recent years, it has become increasingly apparent that several effectors of plant-associated organisms are repeat-containing proteins (RCPs) that carry tandem or non-tandem arrays of an amino acid sequence or structural motif. In this review, we highlight the diverse roles that these repeat domains play in RCP effector function. We also draw attention to the potential role of these repeat domains in adaptive evolution with regards to RCP effector function and the evasion of effector-triggered immunity. The aim of this review is to increase the profile of RCP effectors from plant-associated organisms.
Collapse
Affiliation(s)
- Carl H. Mesarich
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
- *Correspondence: Carl H. Mesarich
| | - Joanna K. Bowen
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
| | - Cyril Hamiaux
- Human Responses, The New Zealand Institute for Plant & Food Research LimitedAuckland, New Zealand
| | - Matthew D. Templeton
- School of Biological Sciences, The University of AucklandAuckland, New Zealand
- Host–Microbe Interactions, Bioprotection, The New Zealand Institute for Plant & Food Research LtdAuckland, New Zealand
| |
Collapse
|
22
|
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.
Collapse
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:
| |
Collapse
|