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Chantab K, Rao Z, Zheng X, Han R, Cao L. Ascarosides and Symbiotic Bacteria of Entomopathogenic Nematodes Regulate Host Immune Response in Galleria mellonella Larvae. INSECTS 2024; 15:514. [PMID: 39057246 PMCID: PMC11277396 DOI: 10.3390/insects15070514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/20/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024]
Abstract
Insects protect themselves through their immune systems. Entomopathogenic nematodes and their bacterial symbionts are widely used for the biocontrol of economically important pests. Ascarosides are pheromones that regulate nematode behaviors, such as aggregation, avoidance, mating, dispersal, and dauer recovery and formation. However, whether ascarosides influence the immune response of insects remains unexplored. In this study, we co-injected ascarosides and symbiotic Photorhabdus luminescens subsp. kayaii H06 bacteria derived from Heterorhabditis bacteriophora H06 into the last instar larvae of Galleria mellonella. We recorded larval mortality and analyzed the expressions of AMPs, ROS/RNS, and LPSs. Our results revealed a process in which ascarosides, acting as enhancers of the symbiotic bacteria, co-induced G. mellonella immunity by significantly increasing oxidative stress responses and secreting AMPs (gallerimycin, gloverin, and cecropin). This led to a reduction in color intensity and the symbiotic bacteria load, ultimately resulting in delayed host mortality compared to either ascarosides or symbiotic bacteria. These findings demonstrate the cross-kingdom regulation of insects and symbiotic bacteria by nematode pheromones. Furthermore, our results suggest that G. mellonella larvae may employ nematode pheromones secreted by IJs to modulate insect immunity during early infection, particularly in the presence of symbiotic bacteria, for enhancing resistance to invasive bacteria in the hemolymph.
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Affiliation(s)
- Kanjana Chantab
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou 510260, China; (K.C.); (Z.R.); (X.Z.); (R.H.)
- Department of Plant Sciences, Faculty of Agriculture and Technology, Rajamangala University of Technology Isan, Surin 32000, Thailand
| | - Zhongchen Rao
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou 510260, China; (K.C.); (Z.R.); (X.Z.); (R.H.)
| | - Xuehong Zheng
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou 510260, China; (K.C.); (Z.R.); (X.Z.); (R.H.)
| | - Richou Han
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou 510260, China; (K.C.); (Z.R.); (X.Z.); (R.H.)
| | - Li Cao
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou 510260, China; (K.C.); (Z.R.); (X.Z.); (R.H.)
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Perier JD, Kaplan F, Lewis EE, Alborn H, Schliekelman P, Toews MD, Schiller KC, Shapiro-Ilan DI. Enhancing entomopathogenic nematode efficacy with Pheromones: A field study targeting the pecan weevil. J Invertebr Pathol 2024; 203:108070. [PMID: 38311231 DOI: 10.1016/j.jip.2024.108070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 02/10/2024]
Abstract
Consistent efficacy is required for entomopathogenic nematodes to gain wider adoption as biocontrol agents. Recently, we demonstrated that when exposed to nematode pheromone blends, entomopathogenic nematodes showed increased dispersal, infectivity, and efficacy under laboratory and greenhouse conditions. Prior to this study, the impact of entomopathogenic nematode-pheromone combinations on field efficacy had yet to be studied. Steinernema feltiae is a commercially available entomopathogenic nematode that has been shown to increase mortality in insect pests such as the pecan weevil Curculio caryae. In this study, the pecan weevil was used as a model system to evaluate changes in S. feltiae efficacy when treated with a partially purified ascaroside pheromone blend. Following exposure to the pheromone blend, the efficacy of S. feltiae significantly increased as measured with decreased C. caryae survival despite unfavorable environmental conditions. The results of this study highlight a potential new avenue for using entomopathogenic nematodes in field conditions. With increased efficacy, using entomopathogenic nematodes will reduce reliance on conventional management methods in pecan production, translating into more environmentally acceptable practices.
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Affiliation(s)
- Jermaine D Perier
- Department of Entomology, University of Georgia, Tifton, GA 31793, United States
| | - Fatma Kaplan
- Pheronym, Inc., Woodland, CA 95695, United States
| | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, United States
| | - Hans Alborn
- USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, United States
| | - Paul Schliekelman
- Department of Statistics, University of Georgia, Athens, GA 30602, United States
| | - Michael D Toews
- Department of Entomology, University of Georgia, Tifton, GA 31793, United States
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3
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Stevens G, Usman M, Gulzar S, Stevens C, Pimentel E, Erdogan H, Schliekelman P, Kaplan F, Alborn H, Wakil W, Shapiro-Ilan D, Lewis EE. Group Movement in Entomopathogenic Nematodes: Aggregation Levels Vary Based on Context. J Nematol 2024; 56:20240002. [PMID: 38495935 PMCID: PMC10940270 DOI: 10.2478/jofnem-2024-0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2024] [Indexed: 03/19/2024] Open
Abstract
Maintenance of an aggregated population structure implies within-species communication. In mixed-species environments, species-specific aggregations may reduce interspecific competition and promote coexistence. We studied whether movement and aggregation behavior of three entomopathogenic nematode species changed when isolated, as compared to mixed-species arenas. Movement and aggregation of Steinernema carpocapsae, S. feltiae and S. glaseri were assessed in sand. Each species demonstrated significant aggregation when alone. Mixed-species trials involved adding two species of nematodes, either combined in the center of the arena or at separate corners. While individual species became less aggregated than in single-species conditions when co-applied in the same location, they became more aggregated when applied in separate corners. This increased aggregation in separate-corner trials occurred even though the nematodes moved just as far when mixed together as they did when alone. These findings suggest that maintenance of multiple species within the same habitat is driven, at least in part, by species-specific signals that promote conspecific aggregation, and when the species are mixed (as occurs in some commercial formulations involving multiple EPN species), these signaling mechanisms are muddled.
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Affiliation(s)
- Glen Stevens
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
| | - Muhammad Usman
- Department of Entomology, University of Agriculture Faisalabad38000, Pakistan
| | - Sehrish Gulzar
- Department of Entomology, University of Agriculture Faisalabad38000, Pakistan
| | - Cassandra Stevens
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
| | - Eleanor Pimentel
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
| | - Hilal Erdogan
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
- Faculty of Agriculture, Department of Biosystems Engineering, Bursa Uludağ University, Bursa16059, Turkey
| | - Paul Schliekelman
- University of Georgia, Department of Statistics, Athens, GA30602, USA
| | | | - Hans Alborn
- Center for Medical, Agricultural, and Veterinary Entomology, U.S. Department of Agriculture Agricultural Research Service, 1700SW23rd Drive, Gainesville, FL, USA
| | - Waqas Wakil
- Department of Entomology, University of Agriculture Faisalabad38000, Pakistan
| | | | - Edwin E Lewis
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID83844, USA
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4
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Cao M. CRISPR-Cas9 genome editing in Steinernema entomopathogenic nematodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.24.568619. [PMID: 38045388 PMCID: PMC10690278 DOI: 10.1101/2023.11.24.568619] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Molecular tool development in traditionally non-tractable animals opens new avenues to study gene functions in the relevant ecological context. Entomopathogenic nematodes (EPN) Steinernema and their symbiotic bacteria of Xenorhabdus spp are a valuable experimental system in the laboratory and are applicable in the field to promote agricultural productivity. The infective juvenile (IJ) stage of the nematode packages mutualistic symbiotic bacteria in the intestinal pocket and invades insects that are agricultural pests. The lack of consistent and heritable genetics tools in EPN targeted mutagenesis severely restricted the study of molecular mechanisms underlying both parasitic and mutualistic interactions. Here, I report a protocol for CRISPR-Cas9 based genome-editing that is successful in two EPN species, S. carpocapsae and S. hermaphroditum . I adapted a gonadal microinjection technique in S. carpocapsae , which created on-target modifications of a homologue Sc-dpy-10 (cuticular collagen) by homology-directed repair. A similar delivery approach was used to introduce various alleles in S. hermaphroditum including Sh-dpy-10 and Sh-unc-22 (a muscle gene), resulting in visible and heritable phenotypes of dumpy and twitching, respectively. Using conditionally dominant alleles of Sh-unc-22 as a co-CRISPR marker, I successfully modified a second locus encoding Sh-Daf-22 (a homologue of human sterol carrier protein SCPx), predicted to function as a core enzyme in the biosynthesis of nematode pheromone that is required for IJ development. As a proof of concept, Sh-daf-22 null mutant showed IJ developmental defects in vivo ( in insecta) . This research demonstrates that Steinernema spp are highly tractable for targeted mutagenesis and has great potential in the study of gene functions under controlled laboratory conditions within the relevant context of its ecological niche.
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Wu SY, Tang H, Zhang C, Tang F, Lin J, Wang Y, Chen L, Hou Y. Potential of entomopathogenic nematode-infected insect cadavers for the biocontrol of the red imported fire ant Solenopsis invicta. PEST MANAGEMENT SCIENCE 2023; 79:4383-4389. [PMID: 37384581 DOI: 10.1002/ps.7637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/25/2023] [Accepted: 06/29/2023] [Indexed: 07/01/2023]
Abstract
BACKGROUND Entomopathogenic nematodes (EPNs) in an aqueous suspension treatment showed potential in the biocontrol of the red imported fire ant Solenopsis invicta, whereas colony relocation following this inundative application had restricted overall effectiveness. As a novel strategy, EPN pre-infected insect cadavers carrying the next generation of nematode-infective juveniles (IJs) might be used to efficiently manage insect pests. However, this strategy has not been tested on S. invicta. This study evaluated EPNs emerging from wax moth Galleria mellonella cadavers to facilitate infection of S. invicta compared to those used in aqueous suspensions. RESULTS Among seven EPN species, Steinernema riobrave and Heterorhabditis bacteriophora had the highest insecticidal efficiency in aqueous treatment. Cadavers of G. mellonella colonized by either one of two EPN species were not damaged by worker ants, ensuring that the IJs could develop within and emerge successfully from the cadavers. Likewise, compared to an aqueous suspension treatment with an equivalent number of IJs, treatment with an S. riobrave-infected cadaver increased the mortality of S. invicta by ≈10%, whereas infection by H. bacteriophora did not differ between treatments. However, the coexistence of S. riobrave- and H. bacteriophora-infected cadavers adversely affected the control of S. invicta, likely as a result of competition resulting from the increased dispersal of each emerging EPN species. CONCLUSION Using EPN-infected G. mellonella cadavers as a strategy increased the mortality of S. invicta in the laboratory. This study provides positive evidence for the future applications of S. riobrave-infected cadavers in the biocontrol of red imported fire ants. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Sheng-Yen Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Huatao Tang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chen Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Fanxi Tang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jihang Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuxin Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lihong Chen
- Rural Revitalization and Development Center of Duwei Town, Putian, China
| | - Youming Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, Fujian Agriculture and Forestry University, Fuzhou, China
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Topalović O, Geisen S. Nematodes as suppressors and facilitators of plant performance. THE NEW PHYTOLOGIST 2023; 238:2305-2312. [PMID: 37010088 DOI: 10.1111/nph.18925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 03/26/2023] [Indexed: 05/19/2023]
Abstract
Plant-nematode interactions are mainly considered from the negative aspect with a focus on plant-parasitic nematodes (PPNs), which is justified considering the agronomic losses caused by PPNs. Despite the fact that PPNs are outnumbered by nonparasitic free-living nematodes (FLNs), the functional importance of FLNs, especially with regard to plant performance, remains largely unknown. Here, we provide a comprehensive overview and most recent insights into soil nematodes by showing direct and indirect links of both PPNs and FLNs with plant performance. We especially emphasize the knowledge gaps and potential of FLNs as important indirect players in driving plant performance such as stimulating the resistance to pests via improving the disease suppressive activity of the rhizobiome. Together, we present a holistic view of soil nematodes as positive and negative contributors to plant performance, accentuating the positive but underexplored role of FLNs.
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Affiliation(s)
- Olivera Topalović
- Section of Terrestrial Ecology, University of Copenhagen, Copenhagen, DK-2100, Denmark
- Department of Nematology, Wageningen University and Research, Wageningen, 6708PB, the Netherlands
| | - Stefan Geisen
- Department of Nematology, Wageningen University and Research, Wageningen, 6708PB, the Netherlands
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Yang B, Wang J, Zheng X, Wang X. Nematode Pheromones: Structures and Functions. Molecules 2023; 28:molecules28052409. [PMID: 36903652 PMCID: PMC10005090 DOI: 10.3390/molecules28052409] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/01/2023] [Accepted: 03/04/2023] [Indexed: 03/09/2023] Open
Abstract
Pheromones are chemical signals secreted by one individual that can affect the behaviors of other individuals within the same species. Ascaroside is an evolutionarily conserved family of nematode pheromones that play an integral role in the development, lifespan, propagation, and stress response of nematodes. Their general structure comprises the dideoxysugar ascarylose and fatty-acid-like side chains. Ascarosides can vary structurally and functionally according to the lengths of their side chains and how they are derivatized with different moieties. In this review, we mainly describe the chemical structures of ascarosides and their different effects on the development, mating, and aggregation of nematodes, as well as how they are synthesized and regulated. In addition, we discuss their influences on other species in various aspects. This review provides a reference for the functions and structures of ascarosides and enables their better application.
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Parr McQueen J, Gattoni K, Gendron E, Schmidt S, Sommers P, Porazinska DL. External and Internal Microbiomes of Antarctic Nematodes are Distinct, but More Similar to each other than the Surrounding Environment. J Nematol 2023; 55:20230004. [PMID: 36969543 PMCID: PMC10035304 DOI: 10.2478/jofnem-2023-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 03/11/2023] Open
Abstract
Host-associated microbiomes have primarily been examined in the context of their internal microbial communities, but many animal species also contain microorganisms on external host surfaces that are important to host physiology. For nematodes, single strains of bacteria are known to adhere to the cuticle (e.g., Pasteuria penetrans), but the structure of a full external microbial community is uncertain. In prior research, we showed that internal gut microbiomes of nematodes (Plectus murrayi, Eudorylaimus antarcticus) and tardigrades from Antarctica's McMurdo Dry Valleys were distinct from the surrounding environment and primarily driven by host identity. Building on this work, we extracted an additional set of individuals containing intact external microbiomes and amplified them for 16S and 18S rRNA metabarcoding. Our results showed that external bacterial microbiomes were more diverse than internal microbiomes, but less diverse than the surrounding environment. Host-specific bacterial compositional patterns were observed, and external microbiomes were most similar to their respective internal microbiomes. However, external microbiomes were more influenced by the environment than the internal microbiomes were. Non-host eukaryotic communities were similar in diversity to internal eukaryotic communities, but exhibited more stochastic patterns of assembly compared to bacterial communities, suggesting the lack of a structured external eukaryotic microbiome. Altogether, we provide evidence that nematode and tardigrade cuticles are inhabited by robust bacterial communities that are substantially influenced by the host, albeit less so than internal microbiomes are.
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Affiliation(s)
- J. Parr McQueen
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
| | - K. Gattoni
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
| | - E.M.S. Gendron
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
| | - S.K. Schmidt
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, CO 80309Colorado BoulderUSA
| | - P. Sommers
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, CO 80309Colorado BoulderUSA
| | - D. L. Porazinska
- Department of Entomology and Nematology, University of Florida, FL 32611FloridaUSA
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Transcriptome analysis of aphids exposed to glandular trichomes in tomato reveals stress and starvation related responses. Sci Rep 2022; 12:20154. [PMID: 36418431 PMCID: PMC9684535 DOI: 10.1038/s41598-022-24490-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 11/16/2022] [Indexed: 11/26/2022] Open
Abstract
Understanding the responses of insect herbivores to plant chemical defences is pivotal for the management of crops and pests. However, the mechanisms of interaction are not entirely understood. In this study, we compared the whole transcriptome gene expression of the aphid Macrosiphum euphorbiae grown on two different varieties of tomato that differ in their inducible chemical defences. We used two isogenic lines of tomato with a shared genetic background that only differ in the presence of type IV glandular trichomes and their associated acylsucrose excretions. This works also reports a de novo transcriptome of the aphid M. euphorbiae. Subsequently, we identified a unique and distinct gene expression profile for the first time corresponding to aphid´s exposure to type IV glandular trichomes and acylsugars. The analysis of the aphid transcriptome shows that tomato glandular trichomes and their associated secretions are highly efficient in triggering stress-related responses in the aphid, and demonstrating that their role in plant defence goes beyond the physical impediment of herbivore activity. Some of the differentially expressed genes were associated with carbohydrate, lipid and xenobiotic metabolisms, immune system, oxidative stress response and hormone biosynthesis pathways. Also, the observed responses are compatible with a starvation syndrome. The transcriptome analysis puts forward a wide range of genes involved in the synthesis and regulation of detoxification enzymes that reveal important underlying mechanisms in the interaction of the aphid with its host plant and provides a valuable genomic resource for future study of biological processes at the molecular level using this aphid.
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Gaffke AM, Shapiro-Ilan D, Alborn HT. Deadly scents: Exposure to plant volatiles increases mortality of entomopathogenic nematodes during infection. Front Physiol 2022; 13:978359. [PMID: 36187772 PMCID: PMC9518750 DOI: 10.3389/fphys.2022.978359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 08/26/2022] [Indexed: 11/25/2022] Open
Abstract
Plants attacked by insects commonly mobilize various defense mechanisms, including the biosynthesis and release of so-called herbivore-induced plant volatiles (HIPVs). Entomopathogenic nematodes (EPNs) can be attracted to these belowground HIPVs, which can enhance biocontrol services from EPNs. However, recent research has also demonstrated that HIPVs can induce and initiate insect immune responses, decreasing the insect’s susceptibility to pathogens and parasites. Therefore, experiments were conducted to test the impact of HIPVs on insects and EPNs during the initial stage of EPN infection. Compounds that can impact EPN attraction and infectivity such as pregeijerene, β-caryophyllene, and α-pinene, and compounds that have been determined to increase or decrease susceptibility of insects to pathogens, such as (Z)-3-hexenyl acetate, linalool, and β-ocimene, were selected. Exposure of Galleria mellonella larvae to pregeijerene, linalool, β-ocimene and α-pinene during invasion significantly increased mortality of Steinernema diaprepesi and Heterorhabditis bacteriophora after 48 h. Larval treatment with β-caryophyllene only increased mortality for Heterorhabditis bacteriophora. (Z)-3-hexenyl acetate did not cause differential mortality from the controls for either nematode species. In additional experiments, we found that EPNs exposed to α-pinene and linalool were more readily recognized by the insects’ immune cells compared to the control treatment, thus the observed increased mortality was likely due to HIPVs-EPN interactions with the insect’s immune system. These results show that the presence of HIPVs can impact EPN survival in the model host, G. mellonella.
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Affiliation(s)
- Alexander M. Gaffke
- Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL, United States
- Department of Entomology, Louisiana State University, Baton Rouge, LA, United States
- *Correspondence: Alexander M. Gaffke,
| | - David Shapiro-Ilan
- Southeastern Fruit and Tree Nut Research Station, Agricultural Research Service, United States Department of Agriculture, Byron, GA, United States
| | - Hans T. Alborn
- Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, United States Department of Agriculture, Gainesville, FL, United States
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11
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Rutter WB, Franco J, Gleason C. Rooting Out the Mechanisms of Root-Knot Nematode-Plant Interactions. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:43-76. [PMID: 35316614 DOI: 10.1146/annurev-phyto-021621-120943] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Root-knot nematodes (RKNs; Meloidogyne spp.) engage in complex parasitic interactions with many different host plants around the world, initiating elaborate feeding sites and disrupting host root architecture. Although RKNs have been the focus of research for many decades, new molecular tools have provided useful insights into the biological mechanisms these pests use to infect and manipulate their hosts. From identifying host defense mechanisms underlying resistance to RKNs to characterizing nematode effectors that alter host cellular functions, the past decade of research has significantly expanded our understanding of RKN-plant interactions, and the increasing number of quality parasite and host genomes promises to enhance future research efforts into RKNs. In this review, we have highlighted recent discoveries, summarized the current understanding within the field, and provided links to new and useful resources for researchers. Our goal is to offer insights and tools to support the study of molecular RKN-plant interactions.
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Affiliation(s)
- William B Rutter
- US Vegetable Laboratory, USDA Agricultural Research Service, Charleston, South Carolina, USA
| | - Jessica Franco
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA;
| | - Cynthia Gleason
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA;
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12
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Kong X, Huang Z, Gu X, Cui Y, Li J, Han R, Jin Y, Cao L. Dimethyl sulfoxide and ascarosides improve the growth and yields of entomopathogenic nematodes in liquid cultures. J Invertebr Pathol 2022; 193:107800. [PMID: 35870517 DOI: 10.1016/j.jip.2022.107800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/30/2022]
Abstract
Increasing the infective juvenile (IJ) yields of entomopathogenic nematodes in monoxenic culture systems would reduce their production cost for the market. Ascarosides act as universal nematode pheromones with developmental and behavioral effects of nematodes. Dimethyl sulfoxide (DMSO) is unexpectedly found to enhance the IJ yields of entomopathogenic nematodes on fortified nutrient broth plates. In this study, the influence of selected ascarosides (ascr#7, ascr#9 and ascr#11) and DMSO in three concentrations on the IJ yields of S. carpocapsae All and H. bacteriophora H06 in liquid culture flasks was determined, and the critical development parameters (IJ recovery rate, number of hermaphrodites, number of visible eggs in a hermaphrodite) were examined for H. bacteriophora H06. The results demonstrated that IJ yields were significantly improved in the liquid medium containing 0.01 % DMSO, and 0.02 nM ascr#11 for S. carpocapsae All, and 0.1 % and 0.01 % DMSO and 0.02 pM ascr#11 for H. bacteriophora H06 in proper concentrations. Furthermore, it was discovered that increased recovery rate, hermaphrodite numbers and eggs in the hermaphrodites may contribute to the improved IJ yields of H. bacteriophora H06 in DMSO-supplemented liquid medium. Compared with the control flasks, the IJ yields from the flasks containing 0.01 % DMSO were 15 % and 35 % higher for S. carpocapsae All and H. bacteriophora H06 respectively in 15 days. The cost for ascarosides and DMSO is almost negligible. The results would provide practical technology for low-cost commercial production of these nematodes for pest management program.
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Affiliation(s)
- Xiangxin Kong
- Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang, China; Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou 510260, China
| | - Zhihua Huang
- Yuxi Branch of Yunnan Tobacco Company, Engineering Center for Biological Control of Diseases and Pests in Tobacco Industry, Yuxi 653100, Yunnan Province, China
| | - Xinghui Gu
- Yuxi Branch of Yunnan Tobacco Company, Engineering Center for Biological Control of Diseases and Pests in Tobacco Industry, Yuxi 653100, Yunnan Province, China
| | - Yonghe Cui
- Yuxi Branch of Yunnan Tobacco Company, Engineering Center for Biological Control of Diseases and Pests in Tobacco Industry, Yuxi 653100, Yunnan Province, China
| | - Jiangzhou Li
- Yuxi Branch of Yunnan Tobacco Company, Engineering Center for Biological Control of Diseases and Pests in Tobacco Industry, Yuxi 653100, Yunnan Province, China
| | - Richou Han
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou 510260, China
| | - Yongling Jin
- Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang, China.
| | - Li Cao
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou 510260, China.
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13
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Influence of the ascarosides on the recovery, yield and dispersal of entomopathogenic nematodes. J Invertebr Pathol 2022; 188:107717. [PMID: 35031295 DOI: 10.1016/j.jip.2022.107717] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/08/2022] [Accepted: 01/09/2022] [Indexed: 11/23/2022]
Abstract
Recovery, yield, and dispersal are crucial developmental and behavioral indices for the infective juveniles of entomopathogenic nematodes, which are used as biocontrol agents against a variety of agricultural pests. Ascarosides and isopropylstilbene (ISO) function as nematode pheromones with developmental and behavioral effects. In this study, 11 synthesized ascarosides identified from Caenorhabditis elegans, together with ISO identified from Photorhabdus luminescens, were used to determine their influence on the IJ recovery, growth on agar plates, and dispersal of S. carpocapsae All, H. bacteriophora H06 and H. indica LN2 nematodes. Compared with the controls, significant differences in IJ recovery of three nematode species were detected from the supernatants of their corresponding bacterial cultures with almost all ascarosides or isopropylstilbene (ISO) at 0.04 nM in 6 days. The highest IJ recovery percentages was obtained from ISO and ascr#3 for All strain, ascr#5 and ascr#6 for LN2 strain, and ISO and ascr#12 for H06 strain. The ISO detected from Photorhabdus bacteria also induced IJ recovery of S. carpocapsae All. IJ yields was significantly stimulated by all synthesized compounds for S. carpocapsae All, and by most compounds for H. bacteriophora H06. The higher IJ yields varied with ascarosides. Ascr#7 and DMSO was common for the improved IJ yields of both nematode species. The three nematode species showed marked differences in dispersal behavior. In response to the ascarosides or ISO, S. carpocapsae All IJs actively moved with different dispersal rates, H. indica LN2 IJs in very low dispersal rates, and H. bacteriophora H06 IJs in variable and even suppressed rates on the agar plates at least during the assay period. Based on the synthesized standards, ascr#1, ascr#9 and ascr#10 were detected from three nematode species, ascr#5 and ascr#11 also from S. carpocapsae All and H. bacteriophora H06, and ascr#12 also from H. bacteriophora H06 and H. indica LN2. Ascr#9 was most abundant in three nematode species. Compared with the sterile PBS, significantly more ascr#1, ascr#9 and ascr#10 were detected from S. carpocapsae All and H. indica LN2, but less ascr#5 and ascr#11 from S. carpocapsae All, ascr#1, ascr#5, ascr#11 and ascr#12 from H. bacteriophora H06, in the corresponding bacterial supernatant. It seems that the bacterial supernatants could regulate the ascaroside secretion by the three nematode species. These results will provide useful clues for selecting suitable ascarosides to induce the recovery, improve the yield, and enhance the dispersal of the IJs of these nematodes.
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14
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Kamali S, Javadmanesh A, Stelinski LL, Kyndt T, Seifi A, Cheniany M, Zaki-Aghl M, Hosseini M, Heydarpour M, Asili J, Karimi J. Beneficial worm allies warn plants of parasite attack below-ground and reduce above-ground herbivore preference and performance. Mol Ecol 2021; 31:691-712. [PMID: 34706125 DOI: 10.1111/mec.16254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/05/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022]
Abstract
Antagonistic interactions among different functional guilds of nematodes have been recognized for quite some time, but the underlying explanatory mechanisms are unclear. We investigated responses of tomato (Solanum lycopersicum) to two functional guilds of nematodes-plant parasite (Meloidogyne javanica) and entomopathogens (Heterorhabditis bacteriophora, Steinernema feltiae below-ground, and S. carpocapsae)-as well as a leaf mining insect (Tuta absoluta) above-ground. Our results indicate that entomopathogenic nematodes (EPNs): (1) reduced root knot nematode (RKN) infestation below-ground, (2) reduced herbivore (T. absoluta) host preference and performance above-ground, and (3) induced overlapping plant defence responses by rapidly activating polyphenol oxidase and guaiacol peroxidase activity in roots, but simultaneously suppressing this activity in above-ground tissues. Concurrently, we investigated potential plant signalling mechanisms underlying these interactions using transcriptome analyses. We found that both entomopathogens and plant parasites triggered immune responses in plant roots with shared gene expression. Secondary metabolite transcripts induced in response to the two nematode functional guilds were generally overlapping and showed an analogous profile of regulation. Likewise, we show that EPNs modulate plant defence against RKN invasion, in part, by suppressing active expression of antioxidant enzymes. Inoculations of roots with EPN triggered an immune response in tomato via upregulated phenylpropanoid metabolism and synthesis of protease inhibitors in plant tissues, which may explain decreased egg laying and developmental performance exhibited by herbivores on EPN-inoculated plants. Furthermore, changes induced in the volatile organic compound-related transcriptome indicated that M. javanica and/or S. carpocapsae inoculation of plants triggered both direct and indirect defences. Our results support the hypothesis that plants "mistake" subterranean EPNs for parasites, and these otherwise beneficial worms activate a battery of plant defences associated with systemic acquired resistance and/or induced systemic resistance with concomitant antagonistic effects on temporally co-occurring subterranean plant pathogenic nematodes and terrestrial herbivores.
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Affiliation(s)
- Shokoofeh Kamali
- Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Ali Javadmanesh
- Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Lukasz L Stelinski
- Department of Entomology and Nematology, University of Florida Citrus Research and Education Center, Lake Alfred, Florida, USA
| | - Tina Kyndt
- Department of Molecular Biotechnology, Ghent University, Ghent, Belgium
| | - Alireza Seifi
- Department of Biotechnology and Plant Breeding, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Monireh Cheniany
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mohammad Zaki-Aghl
- Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mojtaba Hosseini
- Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Mahyar Heydarpour
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Javad Asili
- Department of Pharmacognosy, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Javad Karimi
- Department of Plant Protection, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
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15
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Grunseich JM, Aguirre NM, Thompson MN, Ali JG, Helms AM. Chemical Cues from Entomopathogenic Nematodes Vary Across Three Species with Different Foraging Strategies, Triggering Different Behavioral Responses in Prey and Competitors. J Chem Ecol 2021; 47:822-833. [PMID: 34415500 PMCID: PMC8613145 DOI: 10.1007/s10886-021-01304-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/09/2021] [Accepted: 07/27/2021] [Indexed: 11/26/2022]
Abstract
Chemical cues play important roles in predator-prey interactions. Semiochemicals can aid predator foraging and alert prey organisms to the presence of predators. Previous work suggests that predator traits differentially influence prey behavior, however, empirical data on how prey organisms respond to chemical cues from predator species with different hunting strategies, and how foraging predators react to cues from potential competitors, is lacking. Furthermore, most research in this area has focused on aquatic and aboveground terrestrial systems, while interactions among belowground, soiling-dwelling organisms have received relatively little attention. Here, we assessed how chemical cues from three species of entomopathogenic nematodes (EPNs), each with a different foraging strategy, influenced herbivore (cucumber beetle) and natural enemy (EPN) foraging behavior. We predicted these cues could serve as chemical indicators of increased predation risk, prey availability, or competition. Our findings revealed that foraging cucumber beetle larvae avoided chemical cues from Heterorhabditis bacteriophora (active-foraging cruiser EPNs), but not Steinernema carpocapsae (ambusher EPNs) or Steinernema riobrave (intermediate-foraging EPNs). In contrast, foraging H. bacteriophora EPNs were attracted to cues produced by the two Steinernema species but not conspecific cues. Notably, the three EPN species produced distinct blends of olfactory cues, with only a few semi-conserved compounds across species. These results indicate that a belowground insect herbivore responds differently to chemical cues from different EPN species, with some EPN species avoiding prey detection. Moreover, the active-hunting EPNs were attracted to heterospecific cues, suggesting these cues indicate a greater probability of available prey, rather than strong interspecific competition.
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Affiliation(s)
- John M Grunseich
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA
| | - Natalie M Aguirre
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA
| | - Morgan N Thompson
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA
| | - Jared G Ali
- Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Anjel M Helms
- Department of Entomology, Texas A&M University, College Station, TX, 77843, USA.
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16
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Costa SR, Ng JLP, Mathesius U. Interaction of Symbiotic Rhizobia and Parasitic Root-Knot Nematodes in Legume Roots: From Molecular Regulation to Field Application. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:470-490. [PMID: 33471549 DOI: 10.1094/mpmi-12-20-0350-fi] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Legumes form two types of root organs in response to signals from microbes, namely, nodules and root galls. In the field, these interactions occur concurrently and often interact with each other. The outcomes of these interactions vary and can depend on natural variation in rhizobia and nematode populations in the soil as well as abiotic conditions. While rhizobia are symbionts that contribute fixed nitrogen to their hosts, parasitic root-knot nematodes (RKN) cause galls as feeding structures that consume plant resources without a contribution to the plant. Yet, the two interactions share similarities, including rhizosphere signaling, repression of host defense responses, activation of host cell division, and differentiation, nutrient exchange, and alteration of root architecture. Rhizobia activate changes in defense and development through Nod factor signaling, with additional functions of effector proteins and exopolysaccharides. RKN inject large numbers of protein effectors into plant cells that directly suppress immune signaling and manipulate developmental pathways. This review examines the molecular control of legume interactions with rhizobia and RKN to elucidate shared and distinct mechanisms of these root-microbe interactions. Many of the molecular pathways targeted by both organisms overlap, yet recent discoveries have singled out differences in the spatial control of expression of developmental regulators that may have enabled activation of cortical cell division during nodulation in legumes. The interaction of legumes with symbionts and parasites highlights the importance of a comprehensive view of root-microbe interactions for future crop management and breeding strategies.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Sofia R Costa
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Jason Liang Pin Ng
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra ACT 2601, Australia
| | - Ulrike Mathesius
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra ACT 2601, Australia
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17
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Daly AJ, De Meester N, Baetens JM, Moens T, De Baets B. Untangling the mechanisms of cryptic species coexistence in a nematode community through individual‐based modelling. OIKOS 2021. [DOI: 10.1111/oik.07989] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Aisling J. Daly
- KERMIT, Dept of Data Analysis and Mathematical Modelling, Ghent Univ. Ghent Belgium
| | - Nele De Meester
- Marine Biology Unit, Dept of Biology, Ghent Univ. Ghent Belgium
| | - Jan M. Baetens
- KERMIT, Dept of Data Analysis and Mathematical Modelling, Ghent Univ. Ghent Belgium
| | - Tom Moens
- Marine Biology Unit, Dept of Biology, Ghent Univ. Ghent Belgium
| | - Bernard De Baets
- KERMIT, Dept of Data Analysis and Mathematical Modelling, Ghent Univ. Ghent Belgium
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18
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Renahan T, Lo WS, Werner MS, Rochat J, Herrmann M, Sommer RJ. Nematode biphasic 'boom and bust' dynamics are dependent on host bacterial load while linking dauer and mouth-form polyphenisms. Environ Microbiol 2021; 23:5102-5113. [PMID: 33587771 DOI: 10.1111/1462-2920.15438] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 01/06/2023]
Abstract
Cross-kingdom interactions involve dynamic processes that shape terrestrial ecosystems and represent striking examples of co-evolution. The multifaceted relationships of entomopathogenic nematodes with their insect hosts and symbiotic bacteria are well-studied cases of co-evolution and pathogenicity. In contrast, microbial interactions in soil after the natural death of insects and other invertebrates are minimally understood. In particular, the turnover and succession of nematodes and bacteria during insect decay have not been well documented - although it represents a rich ecological niche with multiple species interactions. Here, we utilize developmentally plastic nematode Pristionchus pacificus and its associated scarab beetles as models. On La Réunion Island, we collected rhinoceros beetle Oryctes borbonicus, induced death, and placed carcasses in cages both on the island and in a mock-natural environment in the laboratory controlling for high spatial and temporal resolution. Investigating nematode population density and dispersal dynamics, we were able to connect two imperative plasticities, dauer and mouth form. We observed a biphasic 'boom and bust' dispersal dynamic of dauer larvae that corresponds to bacterial load on carcasses but not bacterial type. Strikingly, all post-dauer adults have the predatory mouth form, demonstrating novel intricate interactions on decaying insect hosts. Thus, ecologically relevant survival strategies incorporate critical plastic traits.
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Affiliation(s)
- Tess Renahan
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
| | - Wen-Sui Lo
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
| | - Michael S Werner
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany.,Department of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA
| | - Jacques Rochat
- Micropoda, 2 Rue De l'é'toile du Berger, Residence le Jardin des Épices, La Possession, La Réunion, 97419, France
| | - Matthias Herrmann
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
| | - Ralf J Sommer
- Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck Ring 9, Tübingen, 720976, Germany
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19
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Gupta S, Kumble ALK, Dey K, Bessière JM, Borges RM. The Scent of Life: Phoretic Nematodes Use Wasp Volatiles and Carbon Dioxide to Choose Functional Vehicles for Dispersal. J Chem Ecol 2021; 47:139-152. [PMID: 33475939 DOI: 10.1007/s10886-021-01242-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/18/2020] [Accepted: 01/04/2021] [Indexed: 10/22/2022]
Abstract
Hitchhikers (phoretic organisms) need vehicles to disperse out of unsuitable habitats. Therefore, finding vehicles with the right functional attributes is essential for phoretic organisms. To locate these vehicles, phoretic organisms employ cues within modalities, ranging from visual to chemical senses. However, how hitchhikers discriminate between individual vehicles has rarely been investigated. Using a phoretic nematode community associated with an obligate fig-fig wasp pollination mutualism, we had earlier established that hitchhiking nematodes make decisions based on vehicle species identity and number of conspecific hitchhikers already present on the vehicle. Here we investigate if hitchhikers can differentiate between physiological states of vehicles. We asked whether phoretic nematodes choose between live or dead vehicles present in a chemically crowded environment and we investigated the basis for any discrimination. We conducted two-choice and single-choice behavioral assays using single nematodes and found that plant- and animal-parasitic nematodes preferred live over dead vehicles and used volatiles as a sensory cue to make this decision. However, in single-choice assays, animal-parasitic nematodes were also attracted towards naturally dead or freeze-killed wasps. The volatile profile of the wasps was dominated by terpenes and spiroketals. We examined the volatile blend emitted by the different wasp physiological states and determined a set of volatiles that the phoretic nematodes might use to discriminate between these states which is likely coupled with respired CO2. We determined that CO2 levels emitted by single wasps are sufficient to attract nematodes, demonstrating the high sensitivity of nematodes to this metabolic product.
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Affiliation(s)
- Satyajeet Gupta
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560012, India
| | - Anusha L K Kumble
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560012, India
| | - Kaveri Dey
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560012, India
| | | | - Renee M Borges
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560012, India.
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20
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Erdogan H, Stevens G, Stevens A, Shapiro-Ilan D, Kaplan F, Alborn H, Lewis E. Infected host responses across entomopathogenic nematode phylogeny. J Nematol 2021; 53:e2021-105. [PMID: 34957409 PMCID: PMC8672421 DOI: 10.21307/jofnem-2021-105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Indexed: 11/11/2022] Open
Abstract
We used a phylogenetic framework to examine the relationship between entomopathogenic nematode (EPN) vertical dispersal and infectivity when EPNs are exposed to a mixture of compounds found in late-stage EPN-infected insect cadavers. EPNs from five phylogenetically close and distant species (Heterorhabditis bacteriophora, H. georgiana, H. megidis, H. indica and Steinernema feltiae) were exposed to cadaver macerate produced by their own species’ infection and by H. bacteriophora infected hosts. We found that only three of the five species (H. bacteriophora, H. indica and S. feltiae) responded to exposure to their own macerate by increasing rates of dispersal. When we exposed all five species to a H. bacteriophora infected host macerate, we found that only H. bacteriophora responded by increasing dispersal, and that the most distantly related species (S. feltiae) essentially halted dispersal. These findings suggest that (1) responses to cadaver macerate vary, and (2) there may be a relationship between inherent dispersal rates and sensitivity to macerate exposure, as the most rapidly dispersing species (H. megidis) showed no response to macerate exposure.
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Affiliation(s)
- Hilal Erdogan
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID, 83844
- Faculty of Agriculture, Department of Biosystems Engineering, Bursa Uludağ University, Bursa, 16059, Turkey
| | - Glen Stevens
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID, 83844
| | - Asa Stevens
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID, 83844
| | - David Shapiro-Ilan
- USDA-ARS, Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA, 31008
| | | | - Hans Alborn
- Center for Medical, Agricultural, and Veterinary Entomology, U.S. Department of Agriculture Agricultural Research Service, 1700 SW 23rd Drive, Gainesville, FL
| | - Edwin Lewis
- University of Idaho, Department of Entomology, Plant Pathology and Nematology, Moscow, ID, 83844
- *E-mail:
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21
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Abstract
The last few decades have seen the structural and functional elucidation of small-molecule chemical signals called ascarosides in C. elegans. Ascarosides mediate several biological processes in worms, ranging from development, to behavior. These signals are modular in their design architecture, with their building blocks derived from metabolic pathways. Behavioral responses are not only concentration dependent, but also are influenced by the current physiological state of the animal. Cellular and circuit-level analyses suggest that these signals constitute a complex communication system, employing both synergistic molecular elements and sex-specific neuronal circuits governing the response. In this review, we discuss research from multiple laboratories, including our own, that detail how these chemical signals govern several different social behaviors in C. elegans. We propose that the ascaroside repertoire represents a link between diverse metabolic and neurobiological life-history traits and governs the survival of C. elegans in its natural environment.
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Affiliation(s)
- Caroline S Muirhead
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Jagan Srinivasan
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
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22
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Kaplan F, Shapiro-Ilan D, Schiller KC. Dynamics of entomopathogenic nematode foraging and infectivity in microgravity. NPJ Microgravity 2020; 6:20. [PMID: 32818149 PMCID: PMC7418002 DOI: 10.1038/s41526-020-00110-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/14/2020] [Indexed: 12/25/2022] Open
Abstract
Microgravity is a unique environment to elucidate host-parasite biology. Entomopathogenic nematodes (EPNs), model parasites, kill host insects with mutualistic bacteria and provide environmentally friendly pest control. It is unknown how microgravity affects a multistep insect invasion by parasites with mutualistic bacteria. EPNs respond directionally to electromagnetic cues and their sinusoidal locomotion is affected by various physical factors. Therefore, we expected microgravity to impact EPN functionality. Microgravity experiments during space flight on the International Space Station (ISS) indicated that EPNs successfully emerged from consumed insect host cadavers, moved through soil, found and infected bait insects in a manner equivalent to Earth controls. However, nematodes that developed entirely in space, from the egg stage, died upon return to Earth, unlike controls in microgravity and on Earth. This agricultural biocontrol experiment in space gives insight to long-term space flight for symbiotic organisms, parasite biology, and the potential for sustainable crop protection in space.
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Affiliation(s)
| | - David Shapiro-Ilan
- US Department of Agriculture, Agricultural Research Service, Byron, GA 31008 USA
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23
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Gulzar S, Usman M, Wakil W, Gulcu B, Hazir C, Karagoz M, Hazir S, Shapiro-Ilan DI. Environmental tolerance of entomopathogenic nematodes differs among nematodes arising from host cadavers versus aqueous suspension. J Invertebr Pathol 2020; 175:107452. [PMID: 32763230 DOI: 10.1016/j.jip.2020.107452] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/22/2020] [Accepted: 08/03/2020] [Indexed: 11/16/2022]
Abstract
Environmental factors such as temperature and desiccation impact the survival and efficacy of entomopathogenic nematodes (EPNs). Most studies on environmental tolerance have focused on EPNs applied in aqueous suspension. Another approach for EPN application is via infected host cadavers. Emergence in host cadavers is also more representative of nematodes in natural populations. In prior studies, certain advantages in fitness have been observed with the cadaver application approach relative to aqueous application, yet the impact of environmental stress on these approaches requires investigation. In this study, we compared the effects of various temperatures (heat and cold) and desiccation intervals (48 and 72 hr) on the survival, virulence and reproductive capacity of Heterorhabditis bacteriophora and Steinernema glaseri when applied via cadaver versus aqueous suspension. In the heat tolerance bioassays, following exposure to 30 °C, 35 °C and 37. 5 °C, nematodes (from both species) in the cadaver treatments exhibited higher survival, and reproductive capacity compared with aqueous application. No survival was observed above 37.5 °C regardless of species or application approach. In cold tolerance, no differences were observed between the cadaver and aqueous treatments after a sequence of exposures from 10 °C to -2 °C. In desiccation assays, following exposure to 85% relative humidity for 2 or 3 days, nematodes (from both species) exhibited higher survival and reproduction in the cadaver treatment than in the aqueous treatment, whereas no differences were observed in virulence. This is the first study to find differential stress tolerance among nematodes emerged from infected host cadavers versus those applied in aqueous suspension. Our findings indicate additional advantages when using the cadaver approach for biocontrol applications, and suggest EPNs existing in natural populations may have broader environmental tolerance than those applied via aqueous suspension.
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Affiliation(s)
- Sehrish Gulzar
- Department of Entomology, University of Agriculture Faisalabad 38000, Punjab, Pakistan
| | - Muhammad Usman
- Department of Entomology, University of Agriculture Faisalabad 38000, Punjab, Pakistan
| | - Waqas Wakil
- Department of Entomology, University of Agriculture Faisalabad 38000, Punjab, Pakistan
| | - Baris Gulcu
- Duzce University, Faculty of Arts and Sciences, Department of Biology, Duzce, Turkey
| | - Canan Hazir
- Adnan Menderes University, Aydin Health Services Vocational School, 09100, Aydin, Turkey
| | - Mehmet Karagoz
- Adnan Menderes University, Faculty of Arts and Sciences, Department of Biology, Aydin, Turkey
| | - Selcuk Hazir
- Adnan Menderes University, Faculty of Arts and Sciences, Department of Biology, 09100 Aydin, Turkey.
| | - David I Shapiro-Ilan
- Southeastern Fruit and Tree Nut Research Laboratory, USDA-ARS, Byron, GA 31008, USA.
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24
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Abstract
Different model systems have, over the years, contributed to our current understanding of the molecular mechanisms underpinning the various types of interaction between bacteria and their animal hosts. The genus
Photorhabdus
comprises Gram-negative insect pathogenic bacteria that are normally found as symbionts that colonize the gut of the infective juvenile stage of soil-dwelling nematodes from the family Heterorhabditis. The nematodes infect susceptible insects and release the bacteria into the insect haemolymph where the bacteria grow, resulting in the death of the insect. At this stage the nematodes feed on the bacterial biomass and, following several rounds of reproduction, the nematodes develop into infective juveniles that leave the insect cadaver in search of new hosts. Therefore
Photorhabdus
has three distinct and obligate roles to play during this life-cycle: (1)
Photorhabdus
must kill the insect host; (2)
Photorhabdus
must be capable of supporting nematode growth and development; and (3)
Photorhabdus
must be able to colonize the gut of the next generation of infective juveniles before they leave the insect cadaver. In this review I will discuss how genetic analysis has identified key genes involved in mediating, and regulating, the interaction between
Photorhabdus
and each of its invertebrate hosts. These studies have resulted in the characterization of several new families of toxins and a novel inter-kingdom signalling molecule and have also uncovered an important role for phase variation in the regulation of these different roles.
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Affiliation(s)
- David J Clarke
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
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25
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Conspecific and heterospecific pheromones stimulate dispersal of entomopathogenic nematodes during quiescence. Sci Rep 2020; 10:5738. [PMID: 32235877 PMCID: PMC7109026 DOI: 10.1038/s41598-020-62817-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 03/18/2020] [Indexed: 01/21/2023] Open
Abstract
Ascaroside pheromones stimulate dispersal, a key nematode behavior to find a new food source. Ascarosides produced by entomopathogenic nematodes (EPNs) drive infective juvenile (IJ) emergence from consumed cadavers and dispersal in soil. Without ascarosides from host cadavers, Steinernema feltiae (EPN) reduce dispersal substantially. To determine whether other Steinernema spp. exhibit the same behavior, we compared S. feltiae and S. carpocapsae IJs without host cadaver pheromones. Unlike S. feltiae, S. carpocapsae IJs continued to disperse. However, S. carpocapsae IJs exhibited a temperature-dependent quiescent period. The IJ quiescent period increased at ≤20 °C but did not appear at ≥25 °C. Consistent with this, S. carpocapsae IJ quiescence increased from 30 min to 24 h at ≤20 °C over 60 days. The quiescent period was overcome by dispersal pheromone extracts of their own, other Steinernema spp. and Heterorhabditis spp. Furthermore, S. carpocapsae IJ ambush foraging associated behaviors (tail standing, waving, and jumping) were unaffected by the absence or presence of host cadaver pheromones. For S. feltiae, IJ dispersal declined at all temperatures tested. Understanding the interaction between foraging strategies and pheromone signals will help uncover molecular mechanisms of host seeking, pathogenicity and practical applications to improve the EPN’s efficacy as biocontrol agents.
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Manohar M, Tenjo-Castano F, Chen S, Zhang YK, Kumari A, Williamson VM, Wang X, Klessig DF, Schroeder FC. Plant metabolism of nematode pheromones mediates plant-nematode interactions. Nat Commun 2020; 11:208. [PMID: 31924834 PMCID: PMC6954178 DOI: 10.1038/s41467-019-14104-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 12/13/2019] [Indexed: 12/22/2022] Open
Abstract
Microorganisms and nematodes in the rhizosphere profoundly impact plant health, and small-molecule signaling is presumed to play a central role in plant rhizosphere interactions. However, the nature of the signals and underlying mechanisms are poorly understood. Here we show that the ascaroside ascr#18, a pheromone secreted by plant-parasitic nematodes, is metabolized by plants to generate chemical signals that repel nematodes and reduce infection. Comparative metabolomics of plant tissues and excretions revealed that ascr#18 is converted into shorter side-chained ascarosides that confer repellency. An Arabidopsis mutant defective in two peroxisomal acyl-CoA oxidases does not metabolize ascr#18 and does not repel nematodes, indicating that plants, like nematodes, employ conserved peroxisomal β-oxidation to edit ascarosides and change their message. Our results suggest that plant-editing of nematode pheromones serves as a defense mechanism that acts in parallel to conventional pattern-triggered immunity, demonstrating that plants may actively manipulate chemical signaling of soil organisms.
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Affiliation(s)
| | | | - Shiyan Chen
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Ying K Zhang
- Boyce Thompson Institute, Ithaca, NY, 14853, USA
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Anshu Kumari
- Boyce Thompson Institute, Ithaca, NY, 14853, USA
| | | | - Xiaohong Wang
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Ithaca, NY, 14853, USA
| | - Daniel F Klessig
- Boyce Thompson Institute, Ithaca, NY, 14853, USA.
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.
| | - Frank C Schroeder
- Boyce Thompson Institute, Ithaca, NY, 14853, USA.
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
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Sharma A, Sandhi RK, Reddy GVP. A Review of Interactions between Insect Biological Control Agents and Semiochemicals. INSECTS 2019; 10:insects10120439. [PMID: 31817457 PMCID: PMC6955951 DOI: 10.3390/insects10120439] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 11/29/2019] [Accepted: 12/02/2019] [Indexed: 11/19/2022]
Abstract
Biological control agents and semiochemicals have become essential parts of the integrated pest management of insect pests over recent years, as the incorporation of semiochemicals with natural enemies and entomopathogenic microbials has gained significance. The potential of insect pheromones to attract natural enemies has mainly been established under laboratory conditions, while semiochemicals from plants have been used to attract and retain natural enemies in field conditions using strategies such as trap crops and the push–pull mechanism. The best-known semiochemicals are those used for parasitoids–insect pest–plant host systems. Semiochemicals can also aid in the successful dispersal of entomopathogenic microbials. The use of semiochemicals to disseminate microbial pathogens is still at the initial stage, especially for bacterial and viral entomopathogens. Future studies should focus on the integration of semiochemicals into management strategies for insects, for which several semiochemical compounds have already been studied. More effective formulations of microbial agents, such as granular formulations of entomopathogenic fungi (EPFs), along with bio-degradable trap materials, could improve this strategy. Furthermore, more studies to evaluate species-specific tactics may be needed, especially where more than one key pest is present.
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Affiliation(s)
- Anamika Sharma
- Montana State University, Western Triangle Agricultural Research Center, 9546 Old Shelby Rd, P.O. Box 656, Conrad, MT 59425, USA; (A.S.); (R.K.S.)
| | - Ramandeep Kaur Sandhi
- Montana State University, Western Triangle Agricultural Research Center, 9546 Old Shelby Rd, P.O. Box 656, Conrad, MT 59425, USA; (A.S.); (R.K.S.)
| | - Gadi V. P. Reddy
- USDA-ARS, Southern Insect Management Research Unit, 141 Experiment Station Road, P.O. Box 346, Stoneville, MS 38776, USA
- Correspondence:
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Hartley CJ, Lillis PE, Owens RA, Griffin CT. Infective juveniles of entomopathogenic nematodes (Steinernema and Heterorhabditis) secrete ascarosides and respond to interspecific dispersal signals. J Invertebr Pathol 2019; 168:107257. [PMID: 31634473 DOI: 10.1016/j.jip.2019.107257] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/30/2019] [Accepted: 10/08/2019] [Indexed: 01/23/2023]
Abstract
Ascarosides are a modular series of signalling molecules that are widely conserved in nematodes where they function as pheromones with both behavioural and developmental effects. Here we show that the developmentally arrested infective juvenile (IJ) stage of entomopathogenic nematodes (EPN) secrete ascarosides into the surrounding medium. The exometabolome of Steinernema carpocapsae and Heterorhabditis megidis was examined at 0, 1, 7 and 21 days of storage. The concentration of several ascarosides (ascr#11, ascr#9, ascr#12, ascr#1 and ascr#14 for both species, plus ascr#10 for H. megidis) showed a progressive increase over this period, while the concentration of longer chain ascarosides increased up to day 7, with an apparent decline thereafter. Ascr #9 was the main ascaroside produced by both species. Similar ascarosides were found over a 7-day period for Steinernema longicaudum and S. feltiae. Ascaroside blends have previously been shown to promote nematode dispersal. S. carpocapsae and H. megidis IJs were stored for up to 12 weeks and assayed at intervals. IJs where exometabolome was allowed to accumulate showed higher dispersal rates than those where water was changed frequently, indicating that IJ exometabolome maintained high dispersal. Infectivity was not affected. IJ exometabolome accumulated over 7 days promoted dispersal of freshly harvested IJs, both of their own and other EPN species. Similarly, extracts of nematode-infected cadavers promoted dispersal of con- and heterospecific IJs. Thus, IJs are encouraged to disperse from a source cadaver or from other crowded conditions by public information cues, a finding that may have application in enhancing biocontrol. However, the complexity of the ascaroside blend produced by IJs suggests that it may have ecological functions other than dispersal.
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Affiliation(s)
- Cathryn J Hartley
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Peter E Lillis
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Rebecca A Owens
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Christine T Griffin
- Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland.
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Roder AC, Wang Y, Butcher RA, Stock SP. Influence of symbiotic and non-symbiotic bacteria on pheromone production in Steinernema nematodes (Nematoda, Steinernematidae). ACTA ACUST UNITED AC 2019; 222:jeb.212068. [PMID: 31511342 DOI: 10.1242/jeb.212068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/04/2019] [Indexed: 11/20/2022]
Abstract
In this study, we assessed the effect of symbiotic (cognate and non-cognate) and non-symbiotic bacteria on ascaroside production of first-generation adults in two Steinernema spp.: S. carpocapsae All strain and S. feltiae SN strain. Each nematode species was reared under three bacterial scenarios: (1) cognate symbiotic, (2) non-cognate symbiotic strain and (3) non-cognate symbiotic species. Our results showed S. carpocapsae produced four quantifiable ascaroside molecules: asc-C5, asc-C6, asc-C7 and asc-C11, whereas in S. feltiae only three molecules were detected: asc-C5, asc-C7 and asc-C11. Bacterial conditions did not significantly affect the quantity of the secreted ascarosides in first-generation adults of S. carpocapsae However, in S. feltiae, Xenorhabdus nematophila All strain influenced the production of two ascaroside molecules: asc-C5 and asc-C11.
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Affiliation(s)
- Alexandra C Roder
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Yuting Wang
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - S Patricia Stock
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA .,Department of Entomology, University of Arizona, Forbes Building Rm 410, 1140 E. South Campus Drive, Tucson, AZ 85721, USA
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30
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Kin K, Baiocchi T, Dillman AR. Dispersal and Repulsion of Entomopathogenic Nematodes to Prenol. BIOLOGY 2019; 8:biology8030058. [PMID: 31382480 PMCID: PMC6783912 DOI: 10.3390/biology8030058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/02/2022]
Abstract
Chemosensory cues are crucial for entomopathogenic nematodes (EPNs)—a guild of insect-killing parasitic nematodes that are used as biological control agents against a variety of agricultural pests. Dispersal is an essential element of the EPN life cycle in which newly developed infective juveniles (IJs) emerge and migrate away from a resource-depleted insect cadaver in order to search for new hosts. Emergence and dispersal are complex processes that involve biotic and abiotic factors, however, the elements that result in EPN dispersal behaviors have not been well-studied. Prenol is a simple isoprenoid and a natural alcohol found in association with EPN-infected, resource-depleted insect cadavers, and this odorant has been speculated to play a role in dispersal behavior in EPNs. This hypothesis was tested by evaluating the behavioral responses of five different species of EPNs to prenol both as a distal-chemotactic cue and as a dispersal cue. The results indicate that prenol acted as a repulsive agent for all five species tested, while only two species responded to prenol as a dispersal cue.
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Affiliation(s)
- Kassandra Kin
- Department of Nematology, University of California Riverside, Riverside, CA 92521, USA
| | - Tiffany Baiocchi
- Department of Nematology, University of California Riverside, Riverside, CA 92521, USA
| | - Adler R Dillman
- Department of Nematology, University of California Riverside, Riverside, CA 92521, USA.
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Oliveira-Hofman C, Kaplan F, Stevens G, Lewis E, Wu S, Alborn HT, Perret-Gentil A, Shapiro-Ilan DI. Pheromone extracts act as boosters for entomopathogenic nematodes efficacy. J Invertebr Pathol 2019; 164:38-42. [PMID: 31034842 DOI: 10.1016/j.jip.2019.04.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 11/17/2022]
Abstract
Inconsistency in entomopathogenic nematode (EPN) efficacy is still one of the biggest challenges for the wider adoption of EPNs as biocontrol agents. Previous studies demonstrated that extracts from EPN-infected hosts enhance dispersal and efficacy, two key factors in success of EPNs. Some active components in the insect host cadavers responsible for dispersal, ascarosides, have been identified as nematode pheromones. We hypothesized that pheromone extracts increase dispersal of EPN infective juveniles (IJs) leading to increased efficacy. First, we determined whether pheromone extracts improved IJ movement/dispersal in soil columns baited with Tenebrio molitor larvae. We found that pheromone extracts induced higher numbers of Steinernema carpocapsae and Steinernema feltiae IJs to move towards T. molitor larvae in the bottom of the column compared to IJs treated with infected cadaver macerate and water, positive and negative controls, respectively. Furthermore, the number of S. carpocapsae IJs that invaded T. molitor larvae was higher for the pheromone extract treatment than the controls. S. feltiae IJs that were pretreated with pheromone extracts and macerate (positive control) infected T. molitor at the same rate but invasion was superior to IJs that were treated with water. Consistent with the soil column tests, both S. carpocapsae and S. feltiae IJs treated with pheromone extracts performed better in killing larvae of two economically important insect larvae, pecan weevil, Curculio caryae, and black soldier fly, Hermetia illucens, in greenhouse tests compared to IJs treated with water. We demonstrated pheromone-mediated behavioral manipulation of a biological control agent to enhance pest control potential. Conceivably, nematodes can be exposed to efficacy-enhancing pheromones prior to field application.
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Affiliation(s)
| | | | - Glen Stevens
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | - Edwin Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | | | - Hans T Alborn
- USDA-ARS Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA
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Helms AM, Ray S, Matulis NL, Kuzemchak MC, Grisales W, Tooker JF, Ali JG. Chemical cues linked to risk: Cues from below‐ground natural enemies enhance plant defences and influence herbivore behaviour and performance. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13297] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Anjel M. Helms
- Department of Entomology Texas A&M University College Station Texas
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
| | - Swayamjit Ray
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
| | - Nina L. Matulis
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
| | - Margaret C. Kuzemchak
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
| | - William Grisales
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
| | - John F. Tooker
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
| | - Jared G. Ali
- Department of Entomology, Center for Chemical Ecology The Pennsylvania State University University Park Pennsylvania
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33
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Wu S, Kaplan F, Lewis E, Alborn HT, Shapiro-Ilan DI. Infected host macerate enhances entomopathogenic nematode movement towards hosts and infectivity in a soil profile. J Invertebr Pathol 2018; 159:141-144. [DOI: 10.1016/j.jip.2018.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/09/2018] [Accepted: 10/15/2018] [Indexed: 11/30/2022]
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McGrath PT, Ruvinsky I. A primer on pheromone signaling in Caenorhabditis elegans for systems biologists. ACTA ACUST UNITED AC 2018; 13:23-30. [PMID: 30984890 DOI: 10.1016/j.coisb.2018.08.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Individuals communicate information about their age, sex, social status, and recent life history with other members of their species through the release of pheromones, chemical signals that elicit behavioral or physiological changes in the recipients. Pheromones provide a fascinating example of information exchange: animals have evolved intraspecific languages in the presence of eavesdroppers and cheaters. In this review, we discuss the recent work using the nematode C. elegans to decipher its chemical language through the analysis of ascaroside pheromones. Genetic dissection has started to identify the enzymes that produce pheromones and the neural circuits that process these signals. Ecological experiments have characterized the biotic environment of C. elegans and its relatives, including ecological relationships with a variety of species that sense or release similar blends of ascarosides. Systems biology approaches should be fruitful in understanding the organization and function of communication systems in C. elegans.
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Affiliation(s)
- Patrick T McGrath
- Department of Biological Sciences, Department of Physics; Georgia Institute of Technology, Atlanta, GA 30332.
| | - Ilya Ruvinsky
- Department of Molecular Biosciences; Northwestern University, Evanston, IL 60208.
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35
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Zhao L, Ahmad F, Lu M, Zhang W, Wickham JD, Sun J. Ascarosides Promote the Prevalence of Ophiostomatoid Fungi and an Invasive Pathogenic Nematode, Bursaphelenchus xylophilus. J Chem Ecol 2018; 44:701-710. [PMID: 30033490 DOI: 10.1007/s10886-018-0996-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/08/2018] [Accepted: 07/12/2018] [Indexed: 01/28/2023]
Abstract
Understanding the coevolution of pathogens and their associated mycoflora depend upon a proper elucidation of the basis of their chemical communication. In the case of pine wilt disease, the mutual interactions between cerambycid beetles, invasive pathogenic nematodes, (Bursaphelenchus xylophilus) and their symbiotic ophiostomatoid fungi provide a unique opportunity to understand the role of small molecules in mediating their chemical communication. Nematodes produce ascarosides, a highly conserved family of small molecules that serve essential functions in nematode biology and ecology. Here we demonstrated that the associated fungi, one of the key natural food resources of pine wood nematodes, can detect and respond to these ascarosides. We found that ascarosides significantly increase the growth of L. pini-densiflorae and Sporothrix sp. 1, which are native fungal species in China that form a symbiotic relationship with pinewood nematodes. Hyphal mass of L. pini-densiflorae increased when treated with asc-C5 compared to other ophiostomatoid species. Field results demonstrated that in forests where higher numbers of PWN were isolated from beetle galleries, L. pini-densiflorae had been prevalent; the same results were confirmed in laboratory studies. Furthermore, when treated with asc-C5, L. pini-densiflorae responded by increasing its production of spores, which leads to a higher likelihood of dispersal by insect vectors, hence explaining the dominance of L. pini-densiflorae over S. sp. 1 in the Tianwang and Nanlu Mountains within the Northern Forestry Centre of China. These findings provide an emphatic representation of coevolution of pine wood nematode and its associated fungi. Our results lay a broader foundation for a better understanding of inter-kingdom mutualisms and the chemical signals that mediate their establishment.
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Affiliation(s)
- Lilin Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Faheem Ahmad
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, 45550, Pakistan
| | - Min Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wei Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 10049, China
| | - Jacob D Wickham
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jianghua Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 10049, China.
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36
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Labaude S, Griffin CT. Transmission Success of Entomopathogenic Nematodes Used in Pest Control. INSECTS 2018; 9:insects9020072. [PMID: 29925806 PMCID: PMC6023359 DOI: 10.3390/insects9020072] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/15/2018] [Accepted: 06/18/2018] [Indexed: 11/16/2022]
Abstract
Entomopathogenic nematodes from the two genera Steinernema and Heterorhabditis are widely used as biological agents against various insect pests and represent a promising alternative to replace pesticides. Efficacy and biocontrol success can be enhanced through improved understanding of their biology and ecology. Many endogenous and environmental factors influence the survival of nematodes following application, as well as their transmission success to the target species. The aim of this paper is to give an overview of the major topics currently considered to affect transmission success of these biological control agents, including interactions with insects, plants and other members of the soil biota including conspecifics.
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Affiliation(s)
- Sophie Labaude
- Department of Biology, Maynooth University, W23 A023 Maynooth, Co. Kildare, Ireland.
| | - Christine T Griffin
- Department of Biology, Maynooth University, W23 A023 Maynooth, Co. Kildare, Ireland.
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37
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Mattiucci S, Cipriani P, Levsen A, Paoletti M, Nascetti G. Molecular Epidemiology of Anisakis and Anisakiasis: An Ecological and Evolutionary Road Map. ADVANCES IN PARASITOLOGY 2018. [PMID: 29530312 DOI: 10.1016/bs.apar.2017.12.001] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review addresses the biodiversity, biology, distribution, ecology, epidemiology, and consumer health significance of the so far known species of Anisakis, both in their natural hosts and in human accidental host populations, worldwide. These key aspects of the Anisakis species' biology are highlighted, since we consider them as main driving forces behind which most of the research in this field has been carried out over the past decade. From a public health perspective, the human disease caused by Anisakis species (anisakiasis) appears to be considerably underreported and underestimated in many countries or regions around the globe. Indeed, when considering the importance of marine fish species as part of the everyday diet in many coastal communities around the globe, there still exist significant knowledge gaps as to local epidemiological and ecological drivers of the transmission of Anisakis spp. to humans. We further identify some key knowledge gaps related to Anisakis species epidemiology in both natural and accidental hosts, to be filled in light of new 'omic' technologies yet to be fully developed. Moreover, we suggest that future Anisakis research takes a 'holistic' approach by integrating genetic, ecological, immunobiological, and environmental factors, thus allowing proper assessment of the epidemiology of Anisakis spp. in their natural hosts, in human populations, and in the marine ecosystem, in both space and time.
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38
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Stilwell MD, Cao M, Goodrich-Blair H, Weibel DB. Studying the Symbiotic Bacterium Xenorhabdus nematophila in Individual, Living Steinernema carpocapsae Nematodes Using Microfluidic Systems. mSphere 2018; 3:e00530-17. [PMID: 29299529 PMCID: PMC5750387 DOI: 10.1128/msphere.00530-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/29/2017] [Indexed: 01/01/2023] Open
Abstract
Animal-microbe symbioses are ubiquitous in nature and scientifically important in diverse areas, including ecology, medicine, and agriculture. Steinernema nematodes and Xenorhabdus bacteria compose an established, successful model system for investigating microbial pathogenesis and mutualism. The bacterium Xenorhabdus nematophila is a species-specific mutualist of insect-infecting Steinernema carpocapsae nematodes. The bacterium colonizes a specialized intestinal pocket within the infective stage of the nematode, which transports the bacteria between insects that are killed and consumed by the pair for reproduction. Current understanding of the interaction between the infective-stage nematode and its bacterial colonizers is based largely on population-level, snapshot time point studies on these organisms. This limitation arises because investigating temporal dynamics of the bacterium within the nematode is impeded by the difficulty of isolating and maintaining individual living nematodes and tracking colonizing bacterial cells over time. To overcome this challenge, we developed a microfluidic system that enables us to spatially isolate and microscopically observe individual, living Steinernema nematodes and monitor the growth and development of the associated X. nematophila bacterial communities-starting from a single cell or a few cells-over weeks. Our data demonstrate, to our knowledge, the first direct, temporal, in vivo visual analysis of a symbiosis system and the application of this system to reveal continuous dynamics of the symbiont population in the living host animal. IMPORTANCE This paper describes an experimental system for directly investigating population dynamics of a symbiotic bacterium, Xenorhabdus nematophila, in its host-the infective stage of the entomopathogenic nematode Steinernema carpocapsae. Tracking individual and groups of bacteria in individual host nematodes over days and weeks yielded insight into dynamic growth and topology changes of symbiotic bacterial populations within infective juvenile nematodes. Our approach for studying symbioses between bacteria and nematodes provides a system to investigate long-term host-microbe interactions in individual nematodes and extrapolate the lessons learned to other bacterium-animal interactions.
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Affiliation(s)
- Matthew D. Stilwell
- Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Mengyi Cao
- Department of Bacteriology, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Department of Microbiology, University of Tennessee—Knoxville, Knoxville, Tennessee, USA
| | - Douglas B. Weibel
- Department of Biochemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin, USA
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Ruan WB, Shapiro-Ilan D, Lewis EE, Kaplan F, Alborn H, Gu XH, Schliekelman P. Movement patterns in Entomopathogenic nematodes: Continuous vs. temporal. J Invertebr Pathol 2017; 151:137-143. [PMID: 29158014 DOI: 10.1016/j.jip.2017.11.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 12/18/2022]
Abstract
To exploit resources, animals implement various foraging behaviors to increase their fitness. Entomopathogenic nematodes are obligate parasites of insects in nature. In previous studies, entomopathogenic nematodes were reported to exhibit group movement behavior in the presence and absence of insect hosts. However, it was not determined if group movement is continuous or temporal. For example, nematode movement behavior upon emergence from the host might start out in an independent fashion prior to aggregation, or group movement may be exhibited continuously. In the present study, we explored the propensity for innate group movement behavior of two insect parasitic nematodes in two families and genera: Heterorhabditis indica and Steinernema carpocapsae. We hypothesized the nematode populations would initially move independently from their origin and then come together for group movement. Movement patterns were investigated in sand when nematodes were applied in aqueous suspension (via filter paper) to a specific locus or when the nematodes emerged naturally from infected insect hosts. To compare nematode movement behavior over time and space, nematode dispersal was monitored at three distances (2.5, 4.5 and 8.0 cm) from the center (origin) and at two different time periods, 2 days and 3 days after nematode addition. We discovered that nematode dispersal continuously exhibited an aggregative pattern (independent movement was not observed). Results from both nematode species as well as the host-cadaver and filter paper (aqueous nematode suspension) application methods indicated a continuous aggregative pattern. The discovery of continuous aggregative movement patterns in steinernematid and heterorhabditid nematodes elucidates further the complexity of their foraging behavior and may serve as basis for exploring foraging behavior in other host-parasite systems.
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Affiliation(s)
- Wei-Bin Ruan
- College of Life Sciences, Nankai University, Tianjin 30071, China
| | | | - Edwin E Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83844, USA
| | | | - Hans Alborn
- USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA
| | - Xin-Hui Gu
- Yuxi Tobacco Company, Yuxi 653100, Yunnan, China
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An oxytocin-dependent social interaction between larvae and adult C. elegans. Sci Rep 2017; 7:10122. [PMID: 28860630 PMCID: PMC5579267 DOI: 10.1038/s41598-017-09350-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 07/26/2017] [Indexed: 12/21/2022] Open
Abstract
Oxytocin has a conserved role in regulating animal social behaviour including parental-offspring interactions. Recently an oxytocin-like neuropeptide, nematocin, and its cognate receptors have been identified in the nematode Caenorhabditis elegans. We provide evidence for a pheromone signal produced by C. elegans larvae that modifies the behaviour of adult animals in an oxytocin-dependent manner increasing their probability of leaving a food patch which the larvae are populating. This increase is positively correlated to the size of the larval population but cannot be explained by food depletion nor is it modulated by biogenic amines, which suggest it is not an aversive behaviour. Moreover, the food-leaving behaviour is conspecific and pheromone dependent: C. elegans adults respond more strongly to C. elegans larvae compared to other nematode species and this effect is absent in C. elegans daf-22 larvae which are pheromone deficient. Neurotransmitter receptors previously implicated in C. elegans foraging decisions NPR-1 and TYRA-3, for NPY-like neuropeptides and tyramine respectively, do not appear to be involved in oxytocin-dependent adult food-leaving. We conclude oxytocin signals within a novel neural circuit that regulates parental-offspring social behaviour in C. elegans and that this provides evidence for evolutionary conservation of molecular components of a parental decision making behaviour.
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Cao M, Goodrich-Blair H. Ready or Not: Microbial Adaptive Responses in Dynamic Symbiosis Environments. J Bacteriol 2017; 199:e00883-16. [PMID: 28484049 PMCID: PMC5512229 DOI: 10.1128/jb.00883-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In mutually beneficial and pathogenic symbiotic associations, microbes must adapt to the host environment for optimal fitness. Both within an individual host and during transmission between hosts, microbes are exposed to temporal and spatial variation in environmental conditions. The phenomenon of phenotypic variation, in which different subpopulations of cells express distinctive and potentially adaptive characteristics, can contribute to microbial adaptation to a lifestyle that includes rapidly changing environments. The environments experienced by a symbiotic microbe during its life history can be erratic or predictable, and each can impact the evolution of adaptive responses. In particular, the predictability of a rhythmic or cyclical series of environments may promote the evolution of signal transduction cascades that allow preadaptive responses to environments that are likely to be encountered in the future, a phenomenon known as adaptive prediction. In this review, we summarize environmental variations known to occur in some well-studied models of symbiosis and how these may contribute to the evolution of microbial population heterogeneity and anticipatory behavior. We provide details about the symbiosis between Xenorhabdus bacteria and Steinernema nematodes as a model to investigate the concept of environmental adaptation and adaptive prediction in a microbial symbiosis.
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Affiliation(s)
- Mengyi Cao
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Microbiology, University of Tennessee Knoxville, Knoxville, Tennessee, USA
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High Levels of the Xenorhabdus nematophila Transcription Factor Lrp Promote Mutualism with the Steinernema carpocapsae Nematode Host. Appl Environ Microbiol 2017; 83:AEM.00276-17. [PMID: 28389546 DOI: 10.1128/aem.00276-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/04/2017] [Indexed: 11/20/2022] Open
Abstract
Xenorhabdus nematophila bacteria are mutualistic symbionts of Steinernema carpocapsae nematodes and pathogens of insects. The X. nematophila global regulator Lrp controls the expression of many genes involved in both mutualism and pathogenic activities, suggesting a role in the transition between the two host organisms. We previously reported that natural populations of X. nematophila exhibit various levels of Lrp expression and that cells expressing relatively low levels of Lrp are optimized for virulence in the insect Manduca sexta The adaptive advantage of the high-Lrp-expressing state was not established. Here we used strains engineered to express constitutively high or low levels of Lrp to test the model in which high-Lrp-expressing cells are adapted for mutualistic activities with the nematode host. We demonstrate that high-Lrp cells form more robust biofilms in laboratory media than do low-Lrp cells, which may reflect adherence to host tissues. Also, our data showed that nematodes cultivated with high-Lrp strains are more frequently colonized than are those associated with low-Lrp strains. Taken together, these data support the idea that high-Lrp cells have an advantage in tissue adherence and colonization initiation. Furthermore, our data show that high-Lrp-expressing strains better support nematode reproduction than do their low-Lrp counterparts under both in vitro and in vivo conditions. Our data indicate that heterogeneity of Lrp expression in X. nematophila populations provides diverse cell populations adapted to both pathogenic (low-Lrp) and mutualistic (high-Lrp) states.IMPORTANCE Host-associated bacteria experience fluctuating conditions during both residence within an individual host and transmission between hosts. For bacteria that engage in evolutionarily stable, long-term relationships with particular hosts, these fluctuations provide selective pressure for the emergence of adaptive regulatory mechanisms. Here we present evidence that the bacterium Xenorhabdus nematophila uses various levels of the transcription factor Lrp to optimize its association with its two animal hosts, nematodes and insects, with which it behaves as a mutualist and a pathogen, respectively. Building on our previous finding that relatively low cellular levels of Lrp are optimal for pathogenesis, we demonstrate that, conversely, high levels of Lrp promote mutualistic activities with the Steinernema carpocapsae nematode host. These data suggest that X. nematophila has evolved to utilize phenotypic variation between high- and low-Lrp-expression states to optimize its alternating behaviors as a mutualist and a pathogen.
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Masler E, Rogers S, Hooks C. Behavioural differences of Heterodera glycines and Meloidogyne incognita infective juveniles exposed to root extracts in vitro. NEMATOLOGY 2017. [DOI: 10.1163/15685411-00003038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In vitro behaviour of infective second-stage juveniles (J2) of Heterodera glycines and Meloidogyne incognita was compared in the presence and absence of plant root extracts. In an agar plate attraction-retention assay, with samples applied by agar disc infused with water (control) or aqueous test solutions, H. glycines was 15-fold more responsive to a chemical attractant (CaCl2) than was M. incognita. Control discs retained H. glycines at a rate 2.9-fold greater than M. incognita. Crude extracts (slurries; 40 mg dry root (ml water)−1) from roots of six plant species (corn, Zea mays; cucumber, Cucumis sativus; marigold, Tagetes patula; mustard, Sinapis alba; pepper, Capsicum annuum; soybean, Glycine max) differentially affected the two nematodes. Cucumber, marigold, pepper and soybean each attracted H. glycines at rates between 2.2- and 3.6-fold greater than controls. No root preparations were attractive to M. incognita, which were significantly repelled by corn, cucumber, mustard and pepper, relative to controls. Preparation of selected root extract supernatants, which involved vacuum drying, decreased the attractiveness of marigold and soybean to H. glycines by 38 and 82%, respectively, but the effect of pepper was unchanged. Supernatant processing had no effect on M. incognita behaviour. In a liquid-based J2 movement assay, root supernatants from marigold, pepper and soybean at 1 mg dry root ml−1 each decreased the frequency of head movement in H. glycines and M. incognita relative to controls. However, dose responses were detected only with marigold, with maximum decreases in activity at 16 mg dry root ml−1 for each species. These decreases were significantly different at 46 and 66%, respectively, for H. glycines and M. incognita. The behaviour of the two nematodes was qualitatively different in assays that required detection of signals across a short distance (agar assay), whereas qualitative responses were similar when juveniles were immersed in treatment solution (liquid assay). In the latter, quantitative responses to marigold differed significantly between H. glycines and M. incognita J2.
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Affiliation(s)
- Edward P. Masler
- USDA-ARS Nematology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA
| | - Stephen T. Rogers
- USDA-ARS Nematology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA
| | - Cerruti R. R. Hooks
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
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Lacey L, Grzywacz D, Shapiro-Ilan D, Frutos R, Brownbridge M, Goettel M. Insect pathogens as biological control agents: Back to the future. J Invertebr Pathol 2015. [DOI: 10.1016/j.jip.2015.07.009] [Citation(s) in RCA: 545] [Impact Index Per Article: 60.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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45
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Willett DS, Alborn HT, Duncan LW, Stelinski LL. Social Networks of Educated Nematodes. Sci Rep 2015; 5:14388. [PMID: 26404058 PMCID: PMC4585912 DOI: 10.1038/srep14388] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/27/2015] [Indexed: 11/09/2022] Open
Abstract
Entomopathogenic nematodes are obligate lethal parasitoids of insect larvae that navigate a chemically complex belowground environment while interacting with their insect hosts, plants, and each other. In this environment, prior exposure to volatile compounds appears to prime nematodes in a compound specific manner, increasing preference for volatiles they previously were exposed to and decreasing attraction to other volatiles. In addition, persistence of volatile exposure influences this response. Longer exposure not only increases preference, but also results in longer retention of that preference. These entomopathogenic nematodes display interspecific social behavioral plasticity; experienced nematodes influence the behavior of different species. This interspecific social behavioral plasticity suggests a mechanism for rapid adaptation of belowground communities to dynamic environments.
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Affiliation(s)
- Denis S Willett
- University of Florida, Entomology and Nematology Department, Citrus Research and Education Center, Lake Alfred, FL, 33850, USA
| | - Hans T Alborn
- Agricultural Research Service, United States Department of Agriculture, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL, 32608, USA
| | - Larry W Duncan
- University of Florida, Entomology and Nematology Department, Citrus Research and Education Center, Lake Alfred, FL, 33850, USA
| | - Lukasz L Stelinski
- University of Florida, Entomology and Nematology Department, Citrus Research and Education Center, Lake Alfred, FL, 33850, USA
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Manosalva P, Manohar M, von Reuss SH, Chen S, Koch A, Kaplan F, Choe A, Micikas RJ, Wang X, Kogel KH, Sternberg PW, Williamson VM, Schroeder FC, Klessig DF. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance. Nat Commun 2015; 6:7795. [PMID: 26203561 PMCID: PMC4525156 DOI: 10.1038/ncomms8795] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 06/10/2015] [Indexed: 01/27/2023] Open
Abstract
Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated protein kinases, as well as salicylic acid- and jasmonic acid-mediated defense signalling pathways. Ascr#18 perception increases resistance in Arabidopsis, tomato, potato and barley to viral, bacterial, oomycete, fungal and nematode infections. These results indicate that plants recognize ascarosides as a conserved molecular signature of nematodes. Using small-molecule signals such as ascarosides to activate plant immune responses has potential utility to improve economic and environmental sustainability of agriculture.
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Affiliation(s)
- Patricia Manosalva
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, California 92521, USA
| | - Murli Manohar
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | | | - Shiyan Chen
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, USA
| | - Aline Koch
- Research Centre for BioSystems, Land Use, and Nutrition, Justus Liebig University, Giessen D-35392, Germany
| | - Fatma Kaplan
- Kaplan Schiller Research, LLC, Gainesville, Florida 32604, USA
| | - Andrea Choe
- Howard Hughes Medical Institute and Biology Division, California Institute of Technology, Pasadena, California 91125, USA
| | - Robert J. Micikas
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Xiaohong Wang
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, USA
- Robert W. Holley Center for Agriculture and Health, US Department of Agricultural Research Service, Ithaca, New York 14853, USA
| | - Karl-Heinz Kogel
- Research Centre for BioSystems, Land Use, and Nutrition, Justus Liebig University, Giessen D-35392, Germany
| | - Paul W. Sternberg
- Howard Hughes Medical Institute and Biology Division, California Institute of Technology, Pasadena, California 91125, USA
| | - Valerie M. Williamson
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Frank C. Schroeder
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Daniel F. Klessig
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
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47
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Manosalva P, Manohar M, von Reuss SH, Chen S, Koch A, Kaplan F, Choe A, Micikas RJ, Wang X, Kogel KH, Sternberg PW, Williamson VM, Schroeder FC, Klessig DF. Conserved nematode signalling molecules elicit plant defenses and pathogen resistance. Nat Commun 2015. [PMID: 26203561 DOI: 10.1038/ncomss8795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
Abstract
Plant-defense responses are triggered by perception of conserved microbe-associated molecular patterns (MAMPs), for example, flagellin or peptidoglycan. However, it remained unknown whether plants can detect conserved molecular patterns derived from plant-parasitic animals, including nematodes. Here we show that several genera of plant-parasitic nematodes produce small molecules called ascarosides, an evolutionarily conserved family of nematode pheromones. Picomolar to micromolar concentrations of ascr#18, the major ascaroside in plant-parasitic nematodes, induce hallmark defense responses including the expression of genes associated with MAMP-triggered immunity, activation of mitogen-activated protein kinases, as well as salicylic acid- and jasmonic acid-mediated defense signalling pathways. Ascr#18 perception increases resistance in Arabidopsis, tomato, potato and barley to viral, bacterial, oomycete, fungal and nematode infections. These results indicate that plants recognize ascarosides as a conserved molecular signature of nematodes. Using small-molecule signals such as ascarosides to activate plant immune responses has potential utility to improve economic and environmental sustainability of agriculture.
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Affiliation(s)
- Patricia Manosalva
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, California 92521, USA
| | - Murli Manohar
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | | | - Shiyan Chen
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, USA
| | - Aline Koch
- Research Centre for BioSystems, Land Use, and Nutrition, Justus Liebig University, Giessen D-35392, Germany
| | - Fatma Kaplan
- Kaplan Schiller Research, LLC, Gainesville, Florida 32604, USA
| | - Andrea Choe
- Howard Hughes Medical Institute and Biology Division, California Institute of Technology, Pasadena, California 91125, USA
| | - Robert J Micikas
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Xiaohong Wang
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, USA
- Robert W. Holley Center for Agriculture and Health, US Department of Agricultural Research Service, Ithaca, New York 14853, USA
| | - Karl-Heinz Kogel
- Research Centre for BioSystems, Land Use, and Nutrition, Justus Liebig University, Giessen D-35392, Germany
| | - Paul W Sternberg
- Howard Hughes Medical Institute and Biology Division, California Institute of Technology, Pasadena, California 91125, USA
| | - Valerie M Williamson
- Department of Plant Pathology, University of California, Davis, California 95616, USA
| | - Frank C Schroeder
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Daniel F Klessig
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
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Lateral Dispersal and Foraging Behavior of Entomopathogenic Nematodes in the Absence and Presence of Mobile and Non-Mobile Hosts. PLoS One 2015; 10:e0129887. [PMID: 26079715 PMCID: PMC4469322 DOI: 10.1371/journal.pone.0129887] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/15/2015] [Indexed: 11/19/2022] Open
Abstract
Entomopathogenic nematodes have been classified into cruisers (active searchers) and ambushers (sit and wait foragers). However, little is known about their dispersal and foraging behavior at population level in soil. We studied lateral dispersal of the ambush foraging Steinernema carpocapsae (ALL strain) and cruise foraging Heterorhabditis bacteriophora (GPS11 strain) from infected host cadavers in microcosms (0.05 m2) containing Wooster silt-loam soil (Oxyaquic fragiudalf) and vegetation in the presence or absence of non-mobile and mobile hosts. Results showed that the presence of a non-mobile host (Galleria mellonella larva in a wire mesh cage) enhanced H. bacteriophora dispersal for up to 24 hr compared with no-host treatment, but had no impact on S. carpocapsae dispersal. In contrast, presence of a mobile host (G. mellonella larvae) increased dispersal of S. carpocapsae compared with no host treatment, but had no effect on H. bacteriophora dispersal. Also H. bacteriophora was better at infecting non-mobile than mobile hosts released into the microcosms and S. carpocapsae was better at infecting mobile than non-mobile hosts, thus affirming the established cruiser-ambusher theory. However, results also revealed that a large proportion of infective juveniles (IJs) of both species stayed near (≤ 3.8 cm) the source cadaver (88-96% S. carpocapsae; 67-79% H. bacteriophora), and the proportion of IJs reaching the farthest distance (11.4 cm) was significantly higher for S. carpocapsae (1.4%) than H. bacteriophora (0.4%) in the presence of mobile hosts. S. carpocapsae also had higher average population displacement than H. bacteriophora in the presence of both the non-mobile (5.07 vs. 3.6 cm/day) and mobile (8.06 vs. 5.3 cm/day) hosts. We conclude that the two species differ in their dispersal and foraging behavior at the population level and this behavior is affected by both the presence and absence of hosts and by their mobility.
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49
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Demarta L, Hibbard BE, Bohn MO, Hiltpold I. The role of root architecture in foraging behavior of entomopathogenic nematodes. J Invertebr Pathol 2014; 122:32-9. [PMID: 25149039 DOI: 10.1016/j.jip.2014.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/05/2014] [Accepted: 08/11/2014] [Indexed: 01/02/2023]
Abstract
As obligate parasites, entomopathogenic nematodes (EPN) rely on insect hosts to complete their development. In insect pest management, EPN infectiousness has varied a lot. A better understanding of their host-finding behavior in the rhizosphere is therefore crucial to enhance EPN potential in biological control. As previously demonstrated, roots can be used as a pathway to insect hosts by EPN, but this interaction and its impact on EPN foraging remain poorly documented. Three artificial model-roots with different degrees of complexity and connectivity were designed to investigate the impact of root architecture on foraging behavior of the EPN Heterorhabditis megidis. Insect baits were placed at the bottom of each model-root that was subsequently buried in moist sand. After injection of the EPN, the number of EPN-infected baits as well as the number of mature nematodes inside each individual carcass was recorded. The influence of insect-induced root volatiles was also evaluated by spiking the baits with a synthetic version of a natural insect-induced root cue. The ecological relevance of the results was tested in soil with two maize genotypes each exhibiting broadly different root architectures. H. megidi performed better in presence of model-roots. Foraging performances of H. megidis declined with the increasing model-root complexity. Adding the synthetic root volatile dramatically changed this pattern and favored the EPN on the most complex model-roots. H. megidis also moved in the vicinity of maize roots to find the insect baits in soil, and natural root architecture also tended to shape H. megidis foraging behavior. This study adds to the scarce body of literature characterizing physical and chemical interactions between EPN and roots. The present data illustrate that root architecture not only modifies plant quality but also shapes upper trophic levels' ecology.
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Affiliation(s)
- Lanila Demarta
- Division of Plant Sciences, University of Missouri, 205 Curtis Hall, Columbia, MO 65211, USA
| | - Bruce E Hibbard
- USDA-ARS, Plant Genetic Research, University of Missouri, 205 Curtis Hall, Columbia, MO 65211, USA
| | - Martin O Bohn
- Maize Breeding and Genetics, Crop Science Department, University of Illinois, S-110 Turner Hall, 1102 S. Goodwin, Urbana, IL 61801, USA
| | - Ivan Hiltpold
- Division of Plant Sciences, University of Missouri, 205 Curtis Hall, Columbia, MO 65211, USA.
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50
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Farine JP, Cortot J, Ferveur JF. Drosophila adult and larval pheromones modulate larval food choice. Proc Biol Sci 2014; 281:20140043. [PMID: 24741012 DOI: 10.1098/rspb.2014.0043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Insects use chemosensory cues to feed and mate. In Drosophila, the effect of pheromones has been extensively investigated in adults, but rarely in larvae. The colonization of natural food sources by Drosophila buzzatii and Drosophila simulans species may depend on species-specific chemical cues left in the food by larvae and adults. We identified such chemicals in both species and measured their influence on larval food preference and puparation behaviour. We also tested compounds that varied between these species: (i) two larval volatile compounds: hydroxy-3-butanone-2 and phenol (predominant in D. simulans and D. buzzatii, respectively), and (ii) adult cuticular hydrocarbons (CHs). Drosophila buzzatii larvae were rapidly attracted to non-CH adult conspecific cues, whereas D. simulans larvae were strongly repulsed by CHs of the two species and also by phenol. Larval cues from both species generally reduced larval attraction and pupariation on food, which was generally--but not always--low, and rarely reflected larval response. As these larval and adult pheromones specifically influence larval food search and the choice of a pupariation site, they may greatly affect the dispersion and survival of Drosophila species in nature.
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Affiliation(s)
- Jean-Pierre Farine
- Centre des Sciences du Goût et de l'Alimentation, UMR6265 CNRS, UMR1324 INRA, Université de Bourgogne, , 6 Boulevard Gabriel, Dijon 21000, France
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