1
|
Parks SC, Okakpu OK, Azizpor P, Nguyen S, Martinez-Beltran S, Claudio I, Anesko K, Bhatia A, Dhillon HS, Dillman AR. Parasitic nematode secreted phospholipase A 2 suppresses cellular and humoral immunity by targeting hemocytes in Drosophila melanogaster. Front Immunol 2023; 14:1122451. [PMID: 37006283 PMCID: PMC10050561 DOI: 10.3389/fimmu.2023.1122451] [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: 12/12/2022] [Accepted: 02/15/2023] [Indexed: 03/17/2023] Open
Abstract
A key aspect of parasitic nematode infection is the nematodes' ability to evade and/or suppress host immunity. This immunomodulatory ability is likely driven by the release of hundreds of excretory/secretory proteins (ESPs) during infection. While ESPs have been shown to display immunosuppressive effects on various hosts, our understanding of the molecular interactions between individual proteins released and host immunity requires further study. We have recently identified a secreted phospholipase A2 (sPLA2) released from the entomopathogenic nematode (EPN) Steinernema carpocapsae we have named Sc-sPLA2. We report that Sc-sPLA2 increased mortality of Drosophila melanogaster infected with Streptococcus pneumoniae and promoted increased bacterial growth. Furthermore, our data showed that Sc-sPLA2 was able to downregulate both Toll and Imd pathway-associated antimicrobial peptides (AMPs) including drosomycin and defensin, in addition to suppressing phagocytosis in the hemolymph. Sc-sPLA2 was also found to be toxic to D. melanogaster with the severity being both dose- and time-dependent. Collectively, our data highlighted that Sc-sPLA2 possessed both toxic and immunosuppressive capabilities.
Collapse
Affiliation(s)
- Sophia C. Parks
- Department of Nematology, University of California, Riverside, CA, United States
| | - Ogadinma K. Okakpu
- Department of Nematology, University of California, Riverside, CA, United States
| | - Pakeeza Azizpor
- Department of Nematology, University of California, Riverside, CA, United States
| | - Susan Nguyen
- Department of Nematology, University of California, Riverside, CA, United States
| | | | - Isaiah Claudio
- Department of Nematology, University of California, Riverside, CA, United States
| | - Kyle Anesko
- Department of Nematology, University of California, Riverside, CA, United States
| | - Anil Bhatia
- Metabolomics Core Facility, IIGB, University of California, Riverside, CA, United States
| | - Harpal S. Dhillon
- Department of Nematology, University of California, Riverside, CA, United States
| | - Adler R. Dillman
- Department of Nematology, University of California, Riverside, CA, United States
| |
Collapse
|
2
|
A ShK-like Domain from Steinernema carpocapsae with Bioinsecticidal Potential. Toxins (Basel) 2022; 14:toxins14110754. [PMID: 36356004 PMCID: PMC9699480 DOI: 10.3390/toxins14110754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Entomopathogenic nematodes are used as biological control agents against a broad range of insect pests. We ascribed the pathogenicity of these organisms to the excretory/secretory products (ESP) released by the infective nematode. Our group characterized different virulence factors produced by Steinernema carpocapsae that underlie its success as an insect pathogen. A novel ShK-like peptide (ScK1) from this nematode that presents high sequence similarity with the ShK peptide from a sea anemone was successfully produced recombinantly in Escherichia coli. The secondary structure of ScK1 appeared redox-sensitive, exhibiting a far-UV circular dichroism spectrum consistent with an alpha-helical secondary structure. Thermal denaturation of the ScK1 allowed estimating the melting temperature to 59.2 ± 0.1 °C. The results from toxicity assays using Drosophila melanogaster as a model show that injection of this peptide can kill insects in a dose-dependent manner with an LD50 of 16.9 µM per adult within 24 h. Oral administration of the fusion protein significantly reduced the locomotor activity of insects after 48 h (p < 0.05, Tukey's test). These data show that this nematode expresses insecticidal peptides with potential as next-generation insecticides.
Collapse
|
3
|
Okakpu OK, Dillman AR. Review of the Role of Parasitic Nematode Excretory/Secretory Proteins in Host Immunomodulation. J Parasitol 2022; 108:199-208. [DOI: 10.1645/21-33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Ogadinma K. Okakpu
- University of California, Riverside 900 University Avenue, Riverside, California 92521
| | - Adler R. Dillman
- University of California, Riverside 900 University Avenue, Riverside, California 92521
| |
Collapse
|
4
|
Huot L, Bigourdan A, Pagès S, Ogier JC, Girard PA, Nègre N, Duvic B. Partner-specific induction of Spodoptera frugiperda immune genes in response to the entomopathogenic nematobacterial complex Steinernema carpocapsae-Xenorhabdus nematophila. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 108:103676. [PMID: 32184079 DOI: 10.1016/j.dci.2020.103676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 06/10/2023]
Abstract
The Steinernema carpocapsae-Xenorhabdus nematophila association is a nematobacterial complex used in biological control of insect crop pests. The infection success of this dual pathogen strongly depends on its interactions with the host's immune system. Here, we used the lepidopteran pest Spodoptera frugiperda to analyze the respective impact of each partner in the induction of its immune responses. First, we used previously obtained RNAseq data to construct the immunome of S. frugiperda and analyze its induction. We then selected representative genes to study by RT-qPCR their induction kinetics and specificity after independent injections of each partner. We showed that both X. nematophila and S. carpocapsae participate in the induction of stable immune responses to the complex. While X. nematophila mainly induces genes classically involved in antibacterial responses, S. carpocapsae induces lectins and genes involved in melanization and encapsulation. We discuss putative relationships between these differential inductions and the pathogen immunosuppressive strategies.
Collapse
Affiliation(s)
- Louise Huot
- DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | | | - Sylvie Pagès
- DGIMI, Univ Montpellier, INRAE, Montpellier, France
| | | | | | - Nicolas Nègre
- DGIMI, Univ Montpellier, INRAE, Montpellier, France.
| | - Bernard Duvic
- DGIMI, Univ Montpellier, INRAE, Montpellier, France.
| |
Collapse
|
5
|
Chen X, Tan A, Palli SR. Identification and functional analysis of promoters of heat-shock genes from the fall armyworm, Spodoptera frugiperda. Sci Rep 2020; 10:2363. [PMID: 32047182 PMCID: PMC7012861 DOI: 10.1038/s41598-020-59197-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/03/2020] [Indexed: 11/09/2022] Open
Abstract
The functional information on heat-shock proteins (Hsp) and heat-shock promoters from an important agricultural insect pest, Spodoptera frugiperda, is still lacking. We conducted a genome-wide identification of Hsp genes and identified a total of 21 genes belonging to four major insect Hsp families (small heat-shock proteins, Hsp60, Hsp70, and Hsp90) in S. frugiperda. Expression of most of S. frugiperda (SfHsp) genes could be detected in Sf9 cells, embryos and larval tissues of S. frugiperda. The heat-inducible activity of heat-shock promoters from several SfHsp genes was tested in Sf9 cells and embryos. The promoter of SfHsp70D showed the high constitutive activity in cell line and embryos, while the activity of SfHsp20.15 and SfHsp20.71 promoters was most dramatically induced in Sf9 cells and embryos. In embryos, the heat-induced activity of SfHsp20.71 and SfHsp70D promoters outperformed commercially used ie1 and ie2 promoters. The heat-induced activity of SfHsp70D and SfHsp19.07 promoters were more robust than ie2 promoter in Sf9 cells. These SfHsp promoters with high basal activity or with heat-induced activity from low basal activity, could be used in S. frugiperda or other lepidopteran insects for many applications including transgenesis and genome editing.
Collapse
Affiliation(s)
- Xien Chen
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, United States of America
| | - Anjiang Tan
- Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Subba Reddy Palli
- Department of Entomology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY, 40546, United States of America.
| |
Collapse
|
6
|
Zhang K, Baiocchi T, Lu D, Chang DZ, Dillman AR. Differentiating between scavengers and entomopathogenic nematodes: Which is Oscheius chongmingensis? J Invertebr Pathol 2019; 167:107245. [DOI: 10.1016/j.jip.2019.107245] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 01/31/2023]
|
7
|
Yadav S, Eleftherianos I. The Imaginal Disc Growth Factors 2 and 3 participate in the Drosophila response to nematode infection. Parasite Immunol 2018; 40:e12581. [PMID: 30107045 DOI: 10.1111/pim.12581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 07/11/2018] [Accepted: 08/09/2018] [Indexed: 01/13/2023]
Abstract
The Drosophila imaginal disc growth factors (IDGFs) induce the proliferation of imaginal disc cells and terminate cell proliferation at the end of larval development. However, the participation of Idgf-encoding genes in other physiological processes of Drosophila including the immune response to infection is not fully understood. Here, we show the contribution of Idgf2 and Idgf3 in the Drosophila response to infection with Steinernema carpocapsae nematodes carrying or lacking their mutualistic Xenorhabdus nematophila bacteria (symbiotic or axenic nematodes, respectively). We find that Idgf2 and Idgf3 are upregulated in Drosophila larvae infected with symbiotic or axenic Steinernema and inactivation of Idgf2 confers a survival advantage to Drosophila larvae against axenic nematodes. Inactivation of Idgf2 induces the Imd and Jak/Stat pathways, whereas inactivation of Idgf3 induces the Imd, Toll and Jak/Stat pathways. We also show that inactivation of the Imd pathway receptor PGRP-LE upregulates Idgf2 against Steinernema nematode infection. Finally, we demonstrate that inactivation of Idgf3 induces the recruitment of larval haemocytes in response to Steinernema. Our results indicate that Idgf2 and Idgf3 might be involved in different yet crucial immune functions in the Drosophila antinematode immune response. Similar findings will promote the development of new targets for species-specific pest control strategies.
Collapse
Affiliation(s)
- Shruti Yadav
- Department of Biological Sciences, The George Washington University, Washington, District of Columbia
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The George Washington University, Washington, District of Columbia
| |
Collapse
|
8
|
Nematobacterial Complexes and Insect Hosts: Different Weapons for the Same War. INSECTS 2018; 9:insects9030117. [PMID: 30208626 PMCID: PMC6164499 DOI: 10.3390/insects9030117] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/22/2018] [Accepted: 09/06/2018] [Indexed: 12/12/2022]
Abstract
Entomopathogenic nematodes (EPNs) are widely used as biological control agents against insect pests, the efficacy of these organisms strongly depends on the balance between the parasitic strategies and the immune response of the host. This review summarizes roles and relationships between insect hosts and two well-known EPN species, Steinernema feltiae and Steinernema carpocapsae and outlines the main mechanisms of immune recognition and defense of insects. Analyzing information and findings about these EPNs, it is clear that these two species use shared immunosuppression strategies, mainly mediated by their symbiotic bacteria, but there are differences in both the mechanism of evasion and interference of the two nematodes with the insect host immune pathways. Based on published data, S. feltiae takes advantage of the cross reaction between its body surface and some host functional proteins, to inhibit defensive processes; otherwise, secretion/excretion products from S. carpocapsae seem to be the main nematode components responsible for the host immunosuppression.
Collapse
|
9
|
Yadav S, Gupta S, Eleftherianos I. Differential Regulation of Immune Signaling and Survival Response in Drosophila melanogaster Larvae upon Steinernema carpocapsae Nematode Infection. INSECTS 2018; 9:insects9010017. [PMID: 29419764 PMCID: PMC5872282 DOI: 10.3390/insects9010017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 01/27/2018] [Accepted: 02/01/2018] [Indexed: 01/11/2023]
Abstract
Drosophila melanogaster is an excellent model to dissect the molecular components and pathways of the innate anti-pathogen immune response. The nematode parasite Steinernema carpocapsae and its mutualistic bacterium Xenorhabdus nematophila form a complex that is highly pathogenic to insects, including D. melanogaster. We have used symbiotic (carrying X. nematophila) and axenic (lacking X. nematophila) nematodes to probe the regulation of genes belonging to different immune signaling pathways in D. melanogaster larvae and assess the survival response of certain mutants to these pathogens. We found that both types of S. carpocapsae upregulate MyD88 (Toll), but not PGRP-LE (Imd); whereas axenic S. carpocapsae strongly upregulate Wengen (Jnk), Domeless (Jak/Stat), Dawdle (TGFβ, Activin), and Decapentaplegic (TGFβ, BMP). We further found that inactivation of Wengen and Decapentaplegic confers a survival advantage to larvae infected with axenic S. carpocapsae, whereas mutating PGRP-LE promotes the survival of larvae infected with symbiotic nematodes.
Collapse
Affiliation(s)
- Shruti Yadav
- Insect Infection and Immunity Lab., Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
| | - Sonali Gupta
- Insect Infection and Immunity Lab., Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
| | - Ioannis Eleftherianos
- Insect Infection and Immunity Lab., Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
| |
Collapse
|
10
|
Lu D, Macchietto M, Chang D, Barros MM, Baldwin J, Mortazavi A, Dillman AR. Activated entomopathogenic nematode infective juveniles release lethal venom proteins. PLoS Pathog 2017; 13:e1006302. [PMID: 28426766 PMCID: PMC5398726 DOI: 10.1371/journal.ppat.1006302] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/20/2017] [Indexed: 12/20/2022] Open
Abstract
Entomopathogenic nematodes (EPNs) are unique parasites due to their symbiosis with entomopathogenic bacteria and their ability to kill insect hosts quickly after infection. It is widely believed that EPNs rely on their bacterial partners for killing hosts. Here we disproved this theory by demonstrating that the in vitro activated infective juveniles (IJs) of Steinernema carpocapsae (a well-studied EPN species) release venom proteins that are lethal to several insects including Drosophila melanogaster. We confirmed that the in vitro activation is a good approximation of the in vivo process by comparing the transcriptomes of individual in vitro and in vivo activated IJs. We further analyzed the transcriptomes of non-activated and activated IJs and revealed a dramatic shift in gene expression during IJ activation. We also analyzed the venom proteome using mass spectrometry. Among the 472 venom proteins, proteases and protease inhibitors are especially abundant, and toxin-related proteins such as Shk domain-containing proteins and fatty acid- and retinol-binding proteins are also detected, which are potential candidates for suppressing the host immune system. Many of the venom proteins have conserved orthologs in vertebrate-parasitic nematodes and are differentially expressed during IJ activation, suggesting conserved functions in nematode parasitism. In summary, our findings strongly support a new model that S. carpocapsae and likely other Steinernema EPNs have a more active role in contributing to the pathogenicity of the nematode-bacterium complex than simply relying on their symbiotic bacteria. Furthermore, we propose that EPNs are a good model system for investigating vertebrate- and human-parasitic nematodes, especially regarding the function of excretory/secretory products. Steinernema carpocapsae belongs to a special group of insect-parasitic nematodes known as entomopathogenic nematodes (EPNs). These differ from other insect parasites in at least two ways; first they kill their hosts quickly (within 2–3 days), and second they associate with bacteria to facilitate their parasitic lifestyle. The infective stage of these parasites, the infective juvenile (IJ) stage, is the only free-living stage and these IJs are developmentally arrested and only reinitiate development once they are inside a suitable host. Little is known about the early stages of parasitism and how these parasites initiate the parasitic phase of their life cycle and reinitiate development. Here we characterized the changes that occur to the nematodes' physical morphology, gene expression, and the release of protein molecules that accompany the transition from developmentally arrested IJ to active, developing parasite. We showed that contrary to long-held assumptions, the nematodes are not merely transporting pathogenic bacteria but that the nematodes contribute to parasitism by releasing toxic proteins into the host. Many of the S. carpocapsae toxins are also found in species of human-parasitic nematodes, and S. carpocapsae may serve as a valuable model for understanding the specific function of these toxins.
Collapse
Affiliation(s)
- Dihong Lu
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Marissa Macchietto
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California, United States of America
| | - Dennis Chang
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Mirayana M. Barros
- Department of Nematology, University of California, Riverside, California, United States of America
| | - James Baldwin
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California, United States of America
| | - Adler R. Dillman
- Department of Nematology, University of California, Riverside, California, United States of America
- * E-mail:
| |
Collapse
|
11
|
Identification of candidate infection genes from the model entomopathogenic nematode Heterorhabditis bacteriophora. BMC Genomics 2017; 18:8. [PMID: 28049427 PMCID: PMC5209865 DOI: 10.1186/s12864-016-3468-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/23/2016] [Indexed: 12/22/2022] Open
Abstract
Background Despite important progress in the field of innate immunity, our understanding of host immune responses to parasitic nematode infections lags behind that of responses to microbes. A limiting factor has been the obligate requirement for a vertebrate host which has hindered investigation of the parasitic nematode infective process. The nematode parasite Heterorhabditis bacteriophora offers great potential as a model to genetically dissect the process of infection. With its mutualistic Photorhabdus luminescens bacteria, H. bacteriophora invades multiple species of insects, which it kills and exploits as a food source for the development of several nematode generations. The ability to culture the life cycle of H. bacteriophora on plates growing the bacterial symbiont makes it a very exciting model of parasitic infection that can be used to unlock the molecular events occurring during infection of a host that are inaccessible using vertebrate hosts. Results To profile the transcriptional response of an infective nematode during the early stage of infection, we performed next generation RNA sequencing on H. bacteriophora IJs incubated in Manduca sexta hemolymph plasma for 9 h. A subset of up-regulated and down-regulated genes were validated using qRT-PCR. Comparative analysis of the transcriptome with untreated controls found a number of differentially expressed genes (DEGs) which cover a number of different functional categories. A subset of DEGs is conserved across Clade V parasitic nematodes revealing an array of candidate parasitic genes. Conclusions Our analysis reveals transcriptional changes in the regulation of a large number of genes, most of which have not been shown previously to play a role in the process of infection. A significant proportion of these genes are unique to parasitic nematodes, suggesting the identification of a group of parasitism factors within nematodes. Future studies using these candidates may provide functional insight into the process of nematode parasitism and also the molecular evolution of parasitism within nematodes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3468-6) contains supplementary material, which is available to authorized users.
Collapse
|
12
|
Rougon-Cardoso A, Flores-Ponce M, Ramos-Aboites HE, Martínez-Guerrero CE, Hao YJ, Cunha L, Rodríguez-Martínez JA, Ovando-Vázquez C, Bermúdez-Barrientos JR, Abreu-Goodger C, Chavarría-Hernández N, Simões N, Montiel R. The genome, transcriptome, and proteome of the nematode Steinernema carpocapsae: evolutionary signatures of a pathogenic lifestyle. Sci Rep 2016; 6:37536. [PMID: 27876851 PMCID: PMC5120318 DOI: 10.1038/srep37536] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 10/31/2016] [Indexed: 11/13/2022] Open
Abstract
The entomopathogenic nematode Steinernema carpocapsae has been widely used for the biological control of insect pests. It shares a symbiotic relationship with the bacterium Xenorhabdus nematophila, and is emerging as a genetic model to study symbiosis and pathogenesis. We obtained a high-quality draft of the nematode’s genome comprising 84,613,633 bp in 347 scaffolds, with an N50 of 1.24 Mb. To improve annotation, we sequenced both short and long RNA and conducted shotgun proteomic analyses. S. carpocapsae shares orthologous genes with other parasitic nematodes that are absent in the free-living nematode C. elegans, it has ncRNA families that are enriched in parasites, and expresses proteins putatively associated with parasitism and pathogenesis, suggesting an active role for the nematode during the pathogenic process. Host and parasites might engage in a co-evolutionary arms-race dynamic with genes participating in their interaction showing signatures of positive selection. Our analyses indicate that the consequence of this arms race is better characterized by positive selection altering specific functions instead of just increasing the number of positively selected genes, adding a new perspective to these co-evolutionary theories. We identified a protein, ATAD-3, that suggests a relevant role for mitochondrial function in the evolution and mechanisms of nematode parasitism.
Collapse
Affiliation(s)
- Alejandra Rougon-Cardoso
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico.,Laboratory of Agrogenomic Sciences, Universidad Nacional Autónoma de México (UNAM), ENES-León, 37684, León, Guanajuato, Mexico
| | - Mitzi Flores-Ponce
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - Hilda Eréndira Ramos-Aboites
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - Christian Eduardo Martínez-Guerrero
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - You-Jin Hao
- College of Life Science, ChongQing Normal University, ChongQing 401331, China
| | - Luis Cunha
- Cardiff School of Biosciences, Cardiff University, Park Place, Sir Martin Evans Building, Museum Avenue, Cardiff, Wales CF10 3US, UK
| | | | - Cesaré Ovando-Vázquez
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - José Roberto Bermúdez-Barrientos
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - Cei Abreu-Goodger
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| | - Norberto Chavarría-Hernández
- Cuerpo Académico de Biotecnología Agroalimentaria. Instituto de Ciencias Agropecuarias, Universidad Autónoma del Estado de Hidalgo. Av. Universidad Km 1, Rancho Universitario, Tulancingo de Bravo, Hidalgo, C.P. 43600, Mexico
| | - Nelson Simões
- CIRN/Departamento de Biologia, Universidade dos Açores, Rua Mãe de Deus, 13. 9500-321 Ponta Delgada. S. Miguel-Açores, Portugal
| | - Rafael Montiel
- Laboratorio Nacional de Genómica para la Biodiversidad, Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Guanajuato, Mexico
| |
Collapse
|
13
|
Lu D, Baiocchi T, Dillman AR. Genomics of Entomopathogenic Nematodes and Implications for Pest Control. Trends Parasitol 2016; 32:588-598. [PMID: 27142565 PMCID: PMC4969101 DOI: 10.1016/j.pt.2016.04.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 12/28/2022]
Abstract
Entomopathogenic nematodes (EPNs) have been used in biological control but improvement is needed to realize their full potential for broader application in agriculture. Some improvements have been gained through selective breeding and the isolation of additional species and populations. Having genomic sequences for at least six EPNs opens the possibility of genetic improvement, either by facilitating the selection of candidate genes for hypothesis-driven studies of gene-trait relations or by genomics-assisted breeding for desirable traits. However, the genomic data will be of limited use without a more mechanistic understanding of the genes underlying traits that are important for biological control. Additionally, molecular tools are required to fully translate the genomic resources into further functional studies and better biological control.
Collapse
Affiliation(s)
- Dihong Lu
- Department of Nematology, University of California, Riverside, CA 92521, USA
| | - Tiffany Baiocchi
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
| | - Adler R Dillman
- Department of Nematology, University of California, Riverside, CA 92521, USA.
| |
Collapse
|
14
|
Shapiro‐Ilan D, Raymond B. Limiting opportunities for cheating stabilizes virulence in insect parasitic nematodes. Evol Appl 2016; 9:462-70. [PMID: 26989437 PMCID: PMC4778107 DOI: 10.1111/eva.12348] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/28/2015] [Accepted: 11/16/2015] [Indexed: 12/31/2022] Open
Abstract
Cooperative secretion of virulence factors by pathogens can lead to social conflict when cheating mutants exploit collective secretion, but do not contribute to it. If cheats outcompete cooperators within hosts, this can cause loss of virulence. Insect parasitic nematodes are important biocontrol tools that secrete a range of significant virulence factors. Critically, effective nematodes are hard to maintain without live passage, which can lead to virulence attenuation. Using experimental evolution, we tested whether social cheating might explain unstable virulence in the nematode Heterorhabditis floridensis by manipulating relatedness via multiplicity of infection (MOI), and the scale of competition. Passage at high MOI, which should reduce relatedness, led to loss of fitness: virulence and reproductive rate declined together and all eight independent lines suffered premature extinction. As theory predicts, relatedness treatments had more impact under stronger global competition. In contrast, low MOI passage led to more stable virulence and increased reproduction. Moreover, low MOI lineages showed a trade-off between virulence and reproduction, particularly for lines under stronger between-host competition. Overall, this study indicates that evolution of virulence theory is valuable for the culture of biocontrol agents: effective nematodes can be improved and maintained if passage methods mitigate possible social conflicts.
Collapse
Affiliation(s)
| | - Ben Raymond
- Royal Holloway University of LondonEghamSurreyUK
- Imperial College LondonSilwood Park CampusAscotBerksUK
| |
Collapse
|
15
|
Insect Immunity to Entomopathogenic Nematodes and Their Mutualistic Bacteria. Curr Top Microbiol Immunol 2016; 402:123-156. [PMID: 27995342 DOI: 10.1007/82_2016_52] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Entomopathogenic nematodes are important organisms for the biological control of insect pests and excellent models for dissecting the molecular basis of the insect immune response against both the nematode parasites and their mutualistic bacteria. Previous research involving the use of various insects has found distinct differences in the number and nature of immune mechanisms that are activated in response to entomopathogenic nematode parasites containing or lacking their associated bacteria. Recent studies using model insects have started to reveal the identity of certain molecules with potential anti-nematode or antibacterial activity as well as the molecular components that nematodes and their bacteria employ to evade or defeat the insect immune system. Identification and characterization of the genes that regulate the insect immune response to nematode-bacteria complexes will contribute significantly to the development of improved practices to control insects of agricultural and medical importance, and potentially nematode parasites that infect mammals, perhaps even humans.
Collapse
|
16
|
Yaari M, Doron-Faigenboim A, Koltai H, Salame L, Glazer I. Transcriptome analysis of stress tolerance in entomopathogenic nematodes of the genus Steinernema. Int J Parasitol 2015; 46:83-95. [PMID: 26598027 DOI: 10.1016/j.ijpara.2015.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 08/13/2015] [Accepted: 08/14/2015] [Indexed: 11/16/2022]
Abstract
Entomopathogenic nematodes of the genus Steinernema are effective biological control agents. The infective stage of these parasites can withstand environmental stresses such as desiccation and heat, but the molecular and physiological mechanisms involved in this tolerance are poorly understood. We used 454 pyrosequencing to analyse transcriptome expression in Steinernema spp. that differ in their tolerance to stress. We compared these species, following heat and desiccation treatments, with their non-stressed counterparts. More than 98% of the transcripts found matched homologous sequences in the UniRef90 database, mostly nematode genes (85%). Among those, 60.8% aligned to the vertebrate parasites including Ascaris suum, Loa loa, and Brugia malayi, 23.3% aligned to bacteriovores, mostly from the genus Caenorhabditis, and 1% aligned to EPNs. Analysing gene expression patterns of the stress response showed a large fraction of down-regulated genes in the desiccation-tolerant nematode Steinernema riobrave, whereas a larger fraction of the genes in the susceptible Steinernema feltiae Carmiel and Gvulot strains were up-regulated. We further compared metabolic pathways and the expression of specific stress-related genes. In the more tolerant nematode, more genes were down-regulated whereas in the less tolerant strains, more genes were up-regulated. This phenomenon warrants further exploration of the mechanism governing induction of the down-regulation process. The present study revealed many genes and metabolic cycles that are differentially expressed in the stressed nematodes. Some of those are well known in other nematodes or anhydrobiotic organisms, but several are new and should be further investigated for their involvement in desiccation and heat tolerance. Our data establish a foundation for further exploration of stress tolerance in entomopathogenic nematodes and, in the long term, for improving their ability to withstand suboptimal environmental conditions.
Collapse
Affiliation(s)
- Mor Yaari
- Department of Entomology and Nematology, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
| | - Adi Doron-Faigenboim
- Department of Ornamental Horticulture, Agricultural Research Organization, Israel
| | - Hinanit Koltai
- Department of Ornamental Horticulture, Agricultural Research Organization, Israel
| | - Liora Salame
- Department of Entomology and Nematology, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
| | - Itamar Glazer
- Department of Entomology and Nematology, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel.
| |
Collapse
|
17
|
Dillman AR, Macchietto M, Porter CF, Rogers A, Williams B, Antoshechkin I, Lee MM, Goodwin Z, Lu X, Lewis EE, Goodrich-Blair H, Stock SP, Adams BJ, Sternberg PW, Mortazavi A. Comparative genomics of Steinernema reveals deeply conserved gene regulatory networks. Genome Biol 2015; 16:200. [PMID: 26392177 PMCID: PMC4578762 DOI: 10.1186/s13059-015-0746-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/10/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Parasitism is a major ecological niche for a variety of nematodes. Multiple nematode lineages have specialized as pathogens, including deadly parasites of insects that are used in biological control. We have sequenced and analyzed the draft genomes and transcriptomes of the entomopathogenic nematode Steinernema carpocapsae and four congeners (S. scapterisci, S. monticolum, S. feltiae, and S. glaseri). RESULTS We used these genomes to establish phylogenetic relationships, explore gene conservation across species, and identify genes uniquely expanded in insect parasites. Protein domain analysis in Steinernema revealed a striking expansion of numerous putative parasitism genes, including certain protease and protease inhibitor families, as well as fatty acid- and retinol-binding proteins. Stage-specific gene expression of some of these expanded families further supports the notion that they are involved in insect parasitism by Steinernema. We show that sets of novel conserved non-coding regulatory motifs are associated with orthologous genes in Steinernema and Caenorhabditis. CONCLUSIONS We have identified a set of expanded gene families that are likely to be involved in parasitism. We have also identified a set of non-coding motifs associated with groups of orthologous genes in Steinernema and Caenorhabditis involved in neurogenesis and embryonic development that are likely part of conserved protein-DNA relationships shared between these two genera.
Collapse
Affiliation(s)
- Adler R Dillman
- Department of Nematology, University of California, Riverside, CA, 92521, USA.
| | - Marissa Macchietto
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
| | - Camille F Porter
- Department of Biology and Evolutionary Ecology Laboratories, Brigham Young University, Provo, UT, 84602, USA.
| | - Alicia Rogers
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Brian Williams
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Igor Antoshechkin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| | - Ming-Min Lee
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA.
| | - Zane Goodwin
- Division of Biology and Biomedical Sciences, Washington University, St Louis, MO, 63110, USA.
| | - Xiaojun Lu
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - Edwin E Lewis
- Department of Entomology and Nematology, University of California, Davis, CA, 95616, USA.
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.
| | - S Patricia Stock
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA.
| | - Byron J Adams
- Department of Biology and Evolutionary Ecology Laboratories, Brigham Young University, Provo, UT, 84602, USA.
| | - Paul W Sternberg
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
- Howard Hughes Medical Institute, Pasadena, CA, 91125, USA.
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
| |
Collapse
|
18
|
Toubarro D, Avila MM, Montiel R, Simões N. A pathogenic nematode targets recognition proteins to avoid insect defenses. PLoS One 2013; 8:e75691. [PMID: 24098715 PMCID: PMC3787073 DOI: 10.1371/journal.pone.0075691] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/20/2013] [Indexed: 01/18/2023] Open
Abstract
Steinernemacarpocapsae is a nematode pathogenic in a wide variety of insect species. The great pathogenicity of this nematode has been ascribed to its ability to overcome the host immune response; however, little is known about the mechanisms involved in this process. The analysis of an expressed sequence tags (EST) library in the nematode during the infective phase was performed and a highly abundant contig homologous to serine protease inhibitors was identified. In this work, we show that this contig is part of a 641-bp cDNA that encodes a BPTI-Kunitz family inhibitor (Sc-KU-4), which is up-regulated in the parasite during invasion and installation. Recombinant Sc-KU-4 protein was produced in Escherichia coli and shown to inhibit chymotrypsin and elastase activities in a dose-dependent manner by a competitive mechanism with Ki values of 1.8 nM and 2.6 nM, respectively. Sc-KU-4 also inhibited trypsin and thrombin activities to a lesser extent. Studies of the mode of action of Sc-KU-4 and its effects on insect defenses suggest that although Sc-KU-4 did not inhibit the activation of hemocytes or the formation of clotting fibers, it did inhibit hemocyte aggregation and the entrapment of foreign particles by fibers. Moreover, Sc-KU-4 avoided encapsulation and the deposition of clotting materials, which usually occurs in response to foreign particles. We show by protein-protein interaction that Sc-KU-4 targets recognition proteins of insect immune system such as masquerade-like and serine protease-like homologs. The interaction of Sc-KU-4 with these proteins explains the ability of the nematode to overcome host reactions and its large pathogenic spectrum, once these immune proteins are well conserved in insects. The discovery of this inhibitor targeting insect recognition proteins opens new avenues for the development of S. carpocapsae as a biological control agent and provides a new tool to study host-pathogen interactions.
Collapse
Affiliation(s)
- Duarte Toubarro
- IBB/CBA and CIRN/Departamento de Biologia, Universidade dos Açores, Ponta Delgada, Portugal
| | - Mónica Martinez Avila
- IBB/CBA and CIRN/Departamento de Biologia, Universidade dos Açores, Ponta Delgada, Portugal
| | - Rafael Montiel
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato, Mexico
| | - Nelson Simões
- IBB/CBA and CIRN/Departamento de Biologia, Universidade dos Açores, Ponta Delgada, Portugal
- * E-mail:
| |
Collapse
|
19
|
Toubarro D, Avila MM, Hao Y, Balasubramanian N, Jing Y, Montiel R, Faria TQ, Brito RM, Simões N. A serpin released by an entomopathogen impairs clot formation in insect defense system. PLoS One 2013; 8:e69161. [PMID: 23874900 PMCID: PMC3712955 DOI: 10.1371/journal.pone.0069161] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 06/07/2013] [Indexed: 11/18/2022] Open
Abstract
Steinernema carpocapsae is an entomopathogenic nematode widely used for the control of insect pests due to its virulence, which is mainly attributed to the ability the parasitic stage has to overcome insect defences. To identify the mechanisms underlying such a characteristic, we studied a novel serpin-like inhibitor (sc-srp-6) that was detected in a transcriptome analysis. Recombinant Sc-SRP-6 produced in Escherichia coli had a native fold of serpins belonging to the α-1-peptidase family and exhibited inhibitory activity against trypsin and α-chymotrypsin with Ki of 0.42×10−7 M and 1.22×10−7 M, respectively. Functional analysis revealed that Sc-SRP-6 inhibits insect digestive enzymes, thus preventing the hydrolysis of ingested particles. Moreover, Sc-SRP-6 impaired the formation of hard clots at the injury site, a major insect defence mechanism against invasive pathogens. Sc-SRP-6 does not prevent the formation of clot fibres and the activation of prophenoloxidases but impairs the incorporation of the melanin into the clot. Binding assays showed a complex formation between Sc-SRP-6 and three proteins in the hemolymph of lepidopteran required for clotting, apolipophorin, hexamerin and trypsin-like, although the catalytic inhibition occurred exclusively in trypsin-like. This data allowed the conclusion that Sc-SRP-6 promotes nematode virulence by inhibiting insect gut juices and by impairing immune clot reaction.
Collapse
Affiliation(s)
- Duarte Toubarro
- Centro Investigação Recursos Naturais do Centro de Biotecnologia dos Açores, Associate Laboratory of Institute for Biotechnology and Bioengineering, Department of Biology, University of Azores, Ponta Delgada, Portugal
| | - Mónica M. Avila
- Centro Investigação Recursos Naturais do Centro de Biotecnologia dos Açores, Associate Laboratory of Institute for Biotechnology and Bioengineering, Department of Biology, University of Azores, Ponta Delgada, Portugal
| | - YouJin Hao
- Centro Investigação Recursos Naturais do Centro de Biotecnologia dos Açores, Associate Laboratory of Institute for Biotechnology and Bioengineering, Department of Biology, University of Azores, Ponta Delgada, Portugal
| | - Natesan Balasubramanian
- Centro Investigação Recursos Naturais do Centro de Biotecnologia dos Açores, Associate Laboratory of Institute for Biotechnology and Bioengineering, Department of Biology, University of Azores, Ponta Delgada, Portugal
| | - Yingjun Jing
- Centro Investigação Recursos Naturais do Centro de Biotecnologia dos Açores, Associate Laboratory of Institute for Biotechnology and Bioengineering, Department of Biology, University of Azores, Ponta Delgada, Portugal
| | - Rafael Montiel
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, Mexico
| | - Tiago Q. Faria
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rui M. Brito
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Nelson Simões
- Centro Investigação Recursos Naturais do Centro de Biotecnologia dos Açores, Associate Laboratory of Institute for Biotechnology and Bioengineering, Department of Biology, University of Azores, Ponta Delgada, Portugal
- * E-mail:
| |
Collapse
|
20
|
Cloning and molecular analysis of the aspartic protease Sc-ASP110 gene transcript in Steinernema carpocapsae. Parasitology 2013; 140:1158-67. [PMID: 23731543 DOI: 10.1017/s0031182013000577] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Many protease genes have previously been shown to be involved in parasitism and in the development of Steinernema carpocapsae, including a gene predicted to encode an aspartic protease, Sc-ASP110, which was cloned and was analysed in this study. A cDNA encoding Sc-ASP110 was cloned based on an expressed sequence tag (EST) fragment from our EST library. The full-length cDNA of Sc-ASP110 consists of 1112 nucleotides with a catalytic aspartic domain (aa18-337). The putative 341 amino acid residues have a calculated molecular mass of 37·1 kDa and a theoretical pI of 4·7. BLASTp analysis of the Sc-ASP110 amino acid sequence showed 45-77% amino acid sequence identity to parasitic and non-parasitic nematode aspartic proteases. An expression analysis showed that the sc-asp110 gene was upregulated during the late parasitic stage, L4, and 24 h after induction of in vitro nematodes. A sequence comparison revealed that Sc-ASP110 was a member of an aspartic protease family; additionally, a phylogenetic analysis indicated that Sc-ASP110 was clustered with the closely related nematode Steinernema feltiae. In situ hybridization showed that sc-asp110 was expressed in the body walls of dorsal cells. The upregulated Sc-ASP110 expression revealed that this protease could play a role in the late parasitic process. In this study, we have cloned and analysed the gene transcript of Sc-ASP110 in S. carpocapsae.
Collapse
|
21
|
Murfin KE, Dillman AR, Foster JM, Bulgheresi S, Slatko BE, Sternberg PW, Goodrich-Blair H. Nematode-bacterium symbioses--cooperation and conflict revealed in the "omics" age. THE BIOLOGICAL BULLETIN 2012; 223:85-102. [PMID: 22983035 PMCID: PMC3508788 DOI: 10.1086/bblv223n1p85] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nematodes are ubiquitous organisms that have a significant global impact on ecosystems, economies, agriculture, and human health. The applied importance of nematodes and the experimental tractability of many species have promoted their use as models in various research areas, including developmental biology, evolutionary biology, ecology, and animal-bacterium interactions. Nematodes are particularly well suited for the investigation of host associations with bacteria because all nematodes have interacted with bacteria during their evolutionary history and engage in a variety of association types. Interactions between nematodes and bacteria can be positive (mutualistic) or negative (pathogenic/parasitic) and may be transient or stably maintained (symbiotic). Furthermore, since many mechanistic aspects of nematode-bacterium interactions are conserved, their study can provide broader insights into other types of associations, including those relevant to human diseases. Recently, genome-scale studies have been applied to diverse nematode-bacterial interactions and have helped reveal mechanisms of communication and exchange between the associated partners. In addition to providing specific information about the system under investigation, these studies also have helped inform our understanding of genome evolution, mutualism, and innate immunity. In this review we discuss the importance and diversity of nematodes, "omics"' studies in nematode-bacterial systems, and the wider implications of the findings.
Collapse
Affiliation(s)
- Kristen E. Murfin
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706
| | - Adler R. Dillman
- HHMI and Division of Biology, California Institute of Technology, 156-29, Pasadena, CA 91125, USA
| | - Jeremy M. Foster
- Parasitology Division, New England Biolabs, Inc., 240 County Rd, Ipswich, MA 01938, USA
| | - Silvia Bulgheresi
- Department of Genetics in Ecology, University of Vienna, Vienna, Austria
| | - Barton E. Slatko
- Parasitology Division, New England Biolabs, Inc., 240 County Rd, Ipswich, MA 01938, USA
| | - Paul W. Sternberg
- HHMI and Division of Biology, California Institute of Technology, 156-29, Pasadena, CA 91125, USA
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706
- Corresponding author Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Dr., Madison, WI 53706, , phone: 608-265-4537, fax: 608-262-9865
| |
Collapse
|
22
|
Balasubramanian N, Nascimento G, Ferreira R, Martinez M, Simões N. Pepsin-like aspartic protease (Sc-ASP155) cloning, molecular characterization and gene expression analysis in developmental stages of nematode Steinernema carpocapsae. Gene 2012; 500:164-71. [PMID: 22503896 DOI: 10.1016/j.gene.2012.03.062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 03/21/2012] [Accepted: 03/22/2012] [Indexed: 11/17/2022]
Abstract
Steinernema carpocapsae is an insect parasitic nematode associated with the bacterium Xenorhabdus nematophila. These symbiotic complexes are virulent against the insect host. Many protease genes were shown previously to be induced during parasitism, including one predicted to encode an aspartic protease, which was cloned and analyzed in this study. A cDNA encoding Sc-ASP155 was cloned based on the EST fragment. The full-length cDNA of Sc-ASP155 consists of 955 nucleotides with multiple domains, including a signal peptide (aa1-15), a pro-peptide region (aa16-45), and a typical catalytic aspartic domain (aa71-230). The putative 230 amino acid residues have a calculated molecular mass of 23,812Da and a theoretical pI of 5.01. Sc-ASP155 blastp analysis showed 40-62% amino acid sequence identity to aspartic proteases from parasitic and free-living nematodes. Expression analysis showed that the sc-asp155 gene was up-regulated during the initial parasitic stage, especially in L3 gut and 6h induced nematodes. Sequence comparison revealed that Sc-ASP155 was a member of an aspartic protease family and phylogenetic analysis indicated that Sc-ASP155 was clustered with Sc-ASP113. In situ hybridization showed that sc-asp155 was expressed in subventral cells. Additionally, we determined that sc-asp155 is a single-copy gene in S. carpocapsae. Homology modeling showed that Sc-ASP155 adopts a typical aspartic protease structure. The up-regulated Sc-ASP155 expression revealed that this protease could play a role in the parasitic process. In this study, we have cloned the gene and determined the expression of the pepsin-like aspartic protease Sc-ASP155 in S. carpocapsae.
Collapse
Affiliation(s)
- Natesan Balasubramanian
- CIRN and Department of Biology, University of Azores, 9501-855 Ponta Delgada, Azores, Portugal.
| | | | | | | | | |
Collapse
|
23
|
Blaxter M, Kumar S, Kaur G, Koutsovoulos G, Elsworth B. Genomics and transcriptomics across the diversity of the Nematoda. Parasite Immunol 2012; 34:108-20. [PMID: 22044053 DOI: 10.1111/j.1365-3024.2011.01342.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The diversity of biology in nematodes is reflected in the diversity of their genomes. Parasitic species in particular have evolved mechanisms to invade and outwit their hosts, and these offer opportunities for the development of control measures. Genomic analyses can reveal the molecular underpinnings of phenotypes such as parasitism and thus, initiate and support research programmes that explore the manipulation of host and parasite physiologies to achieve favourable outcomes. Wide sampling across nematode diversity allows phylogenetically informed formulation of research hypotheses, identification of core features shared by all species or important evolutionary novelties present in isolated clades. Many nematode species have been investigated through the use of the expressed sequence tag approach, which samples from the transcribed genome. Gene catalogues generated in this way can be explored to reveal the patterns of expression associated with parasitism and candidates for testing as drug targets or vaccine components. Analysis environments, such as NEMBASE facilitate exploitation of these data. The development of new high-throughput DNA-sequencing technologies has facilitated transcriptomic and genomic approaches to parasite biology. Whole genome sequencing offers more complete catalogues of genes and assists a systems approach to phenotype dissection. These efforts are being coordinated through the 959 Nematode Genomes initiative.
Collapse
Affiliation(s)
- M Blaxter
- Institute of Evolutionary Biology, The University of Edinburgh, Edinburgh EH9 3JT, UK.
| | | | | | | | | |
Collapse
|
24
|
Balasubramanian N, Toubarro D, Nascimento G, Ferreira R, Simões N. Purification, molecular characterization and gene expression analysis of an aspartic protease (Sc-ASP113) from the nematode Steinernema carpocapsae during the parasitic stage. Mol Biochem Parasitol 2011; 182:37-44. [PMID: 22178695 DOI: 10.1016/j.molbiopara.2011.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/04/2011] [Accepted: 12/01/2011] [Indexed: 10/14/2022]
Abstract
Steinernema carpocapsae is an insect parasitic nematode associated with the bacterium Xenorhabdus nematophila. During invasion, this nematode is able to express many proteases, including aspartic proteases. Genes encoding these aspartic proteases have been identified in the EST, and aspartic protease has been found in excretory-secretory products. The total protease was shown to digest blood hemoglobin in a zymogram gel. When the protein was partially purified by pepstatin affinity chromatography, it was observed to have high activity against both hemoglobin and the synthetic substrate Phe-Ala-Ala-Phe-(4NO(2))-Phe-Val-Leu (4-pyridylmethyl) ester. The protein was confirmed by mass spectrometry and was found to be encoded by the gene sc-asp113. A cDNA encoding aspartic protease was cloned based on the EST fragment, which was constructed in our lab. The full-length cDNA of Sc-ASP113 consists of 1257 nucleotides encoding a protein with multiple domains, including a signal peptide (aa 1-15), a propeptide region (aa 16-45), and a typical catalytic aspartic domain (aa 68-416). The cleavage site of the signal peptide is predicted to be between Ala15 and Ala16. The putative 418 amino acid residues have a calculated molecular mass of 44,742Da and a theoretical pI of 5.14. BLAST analysis showed 33-56% amino acid sequence identity to aspartic proteases from parasitic and free living nematodes. Expression analysis showed that the sc-asp113 gene was up-regulated during the initial parasitic stage, especially during L3 inside the gut. In vitro, we showed that treatment with insect homogenate for 6h is sufficient to induce the expression of this protease in treated infective juveniles. Sequence comparison and evolutionary analysis revealed that Sc-ASP113 is a member of the aspartic protease family with the potential for tissue degradation. Phylogenetic analysis indicates that Sc-ASP113 branched between Haemonchus contortus and Steinernema feltiae proteases. Homology modeling showed that Sc-ASP113 adopts a typical aspartic protease structure. The up-regulation of Sc-ASP113 expression indicates that this protease could play a role in the parasitic process. To facilitate the exploration of this protease as a virulence factor, here we describe the purification of the protease and its molecular characterization in S. carpocapsae.
Collapse
Affiliation(s)
- Natesan Balasubramanian
- CIRN and Department of Biology, University of Azores, 9501-855 Ponta Delgada, Azores, Portugal.
| | | | | | | | | |
Collapse
|
25
|
Insect immune responses to nematode parasites. Trends Parasitol 2011; 27:537-47. [PMID: 21982477 DOI: 10.1016/j.pt.2011.09.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 09/01/2011] [Accepted: 09/08/2011] [Indexed: 12/16/2022]
Abstract
Host innate immunity plays a central role in detecting and eliminating microbial pathogenic infections in both vertebrate and invertebrate animals. Entomopathogenic or insect pathogenic nematodes are of particular importance for the control of insect pests and vectors of pathogens, while insect-borne nematodes cause serious diseases in humans. Recent work has begun to use the power of insect models to investigate host-nematode interactions and uncover host antiparasitic immune reactions. This review describes recent findings on innate immune evasion strategies of parasitic nematodes and host cellular and humoral responses to the infection. Such information can be used to model diseases caused by human parasitic nematodes and provide clues indicating directions for research into the interplay between vector insects and their invading tropical parasites.
Collapse
|
26
|
Cloning, characterisation and heterologous expression of an astacin metalloprotease, Sc-AST, from the entomoparasitic nematode Steinernema carpocapsae. Mol Biochem Parasitol 2010; 174:101-8. [DOI: 10.1016/j.molbiopara.2010.07.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 06/26/2010] [Accepted: 07/12/2010] [Indexed: 11/22/2022]
|
27
|
Toubarro D, Lucena-Robles M, Nascimento G, Santos R, Montiel R, Veríssimo P, Pires E, Faro C, Coelho AV, Simões N. Serine protease-mediated host invasion by the parasitic nematode Steinernema carpocapsae. J Biol Chem 2010; 285:30666-75. [PMID: 20656686 DOI: 10.1074/jbc.m110.129346] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Steinernema carpocapsae is an insect parasitic nematode used in biological control, which infects insects penetrating by mouth and anus and invading the hemocoelium through the midgut wall. Invasion has been described as a key factor in nematode virulence and suggested to be mediated by proteases. A serine protease cDNA from the parasitic stage was sequenced (sc-sp-1); the recombinant protein was produced in an Escherichia coli system, and a native protein was purified from the secreted products. Both proteins were confirmed by mass spectrometry to be encoded by the sc-sp-1 gene. Sc-SP-1 has a pI of 8.7, a molecular mass of 27.3 kDa, a catalytic efficiency of 22.2 × 10(4) s(-1) m(-1) against N-succinyl-Ala-Ala-Pro-Phe-pNA, and is inhibited by chymostatin (IC 0.07) and PMSF (IC 0.73). Sc-SP-1 belongs to the chymotrypsin family, based on sequence and biochemical analysis. Only the nematode parasitic stage expressed sc-sp-1. These nematodes in the midgut lumen, prepared to invade the insect hemocoelium, expressed higher levels than those already in the hemocoelium. Moreover, parasitic nematode sense insect peritrophic membrane and hemolymph more quickly than they do other tissues, which initiates sc-sp-1 expression. Ex vivo, Sc-SP-1 was able to bind to insect midgut epithelium and to cause cell detachment from basal lamina. In vitro, Sc-SP-1 formed holes in an artificial membrane model (Matrigel), whereas Sc-SP-1 treated with PMSF did not, very likely because it hydrolyzes matrix glycoproteins. These findings highlight the S. carpocapsae-invasive process that is a key step in the parasitism thus opening new perspectives for improving nematode virulence to use in biological control.
Collapse
Affiliation(s)
- Duarte Toubarro
- Departamento de Biologia, Universidade dos Açores, Centro de Investigação de Recursos Naturais, Apartado 1422, Ponta Delgada 9501-801, Portugal
| | | | | | | | | | | | | | | | | | | |
Collapse
|