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Půža V, Machado RAR. Systematics and phylogeny of the entomopathogenic nematobacterial complexes Steinernema-Xenorhabdus and Heterorhabditis-Photorhabdus. ZOOLOGICAL LETTERS 2024; 10:13. [PMID: 39020388 PMCID: PMC11256433 DOI: 10.1186/s40851-024-00235-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 06/08/2024] [Indexed: 07/19/2024]
Abstract
Entomopathogenic nematodes of the genera Steinernema and Heterorhabditis, along with their bacterial symbionts from the genera Xenorhabdus and Photorhabdus, respectively, are important biological control agents against agricultural pests. Rapid progress in the development of genomic tools has catalyzed a transformation of the systematics of these organisms, reshaping our understanding of their phylogenetic and cophlylogenetic relationships. In this review, we discuss the major historical events in the taxonomy and systematics of this group of organisms, highlighting the latest advancements in these fields. Additionally, we synthesize information on nematode-bacteria associations and assess the existing evidence regarding their cophylogenetic relationships.
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Affiliation(s)
- Vladimír Půža
- Institute of Entomology, Biology centre of the Czech Academy of Sciences, Branišovská 31, České Budějovice, 37005, Czech Republic.
- Faculty of Agriculture and Technology, University of South Bohemia, Studentská 1668, České Budějovice, 37005, Czech Republic.
| | - Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, 2000, Switzerland.
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Machado RAR, Malan AP, Boss A, Claasen NJ, Bhat AH, Abolafia J. Photorhabdus africana sp. nov. isolated from Heterorhabditis entomopathogenic nematodes. Curr Microbiol 2024; 81:240. [PMID: 38910178 PMCID: PMC11194217 DOI: 10.1007/s00284-024-03744-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 05/20/2024] [Indexed: 06/25/2024]
Abstract
One Gram-negative, rod-shaped bacterial strain, isolated from an undescribed Heterorhabditis entomopathogenic nematode species was characterized to determine its taxonomic position. The 16S rRNA gene sequences indicate that it belongs to the class Gammaproteobacteria, to the family Morganellaceae, to the genus Photorhabdus, and likely represents a novel bacterial species. This strain, designated here as CRI-LCT, was therefore molecularly, biochemically, and morphologically characterized to describe the novel bacterial species. Phylogenetic reconstructions using 16S rRNA gene sequences show that CRI-LCT is closely related to P. laumondii subsp. laumondii TT01T and to P. laumondii subsp. clarkei BOJ-47T. The 16rRNA gene sequences between CRI-LCT and P. laumondii subsp. laumondii TT01T are 99.1% identical, and between CRI-LCT and P. laumondii subsp. clarkei BOJ-47T are 99.2% identical. Phylogenetic reconstructions using whole genome sequences show that CRI-LCT is closely related to P. laumondii subsp. laumondii TT01T and to P. laumondii subsp. clarkei BOJ-47T. Moreover, digital DNA-DNA hybridization (dDDH) values between CRI-LCT and its two relative species P. laumondii subsp. laumondii TT01T and P. laumondii subsp. clarkei BOJ-47T are 65% and 63%, respectively. In addition, we observed that average nucleotide identity (ANI) values between CRI-LCT and its two relative species P. laumondii subsp. laumondii TT01T and P. laumondii subsp. clarkei BOJ-47T are 95.8% and 95.5%, respectively. These values are below the 70% dDDH and the 95-96% ANI divergence thresholds that delimits prokaryotic species. Based on these genomic divergence values, and the phylogenomic separation, we conclude that CRI-LCT represents a novel bacterial species, for which we propose the name Photorhabdus africana sp. nov. with CRI-LCT (= CCM 9390T = CCOS 2112T) as the type strain. The following biochemical tests allow to differentiate P. africana sp. nov. CRI-LCT from other species of the genus, including its more closely related taxa: β-Galactosidase, citrate utilization, urease and tryptophan deaminase activities, indole and acetoin production, and glucose and inositol oxidation. Our study contributes to a better understanding of the taxonomy and biodiversity of this important bacterial group with great biotechnological and agricultural potential.
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Affiliation(s)
- Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland.
| | - Antoinette P Malan
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Anja Boss
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Nicholle J Claasen
- Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Aashaq Hussain Bhat
- Department of Biosciences and University Center for Research and Development, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India
- Department of Biomaterials, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, 600077, India
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus 'Las Lagunillas', Jaén, Spain
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Machado RAR, Bhat AH, Castaneda-Alvarez C, Půža V, San-Blas E. Photorhabdus aballayi sp. nov. and Photorhabdus luminescens subsp. venezuelensis subsp. nov., isolated from Heterorhabditis amazonensis entomopathogenic nematodes. Int J Syst Evol Microbiol 2023; 73. [PMID: 37171451 DOI: 10.1099/ijsem.0.005872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Six Gram-negative, rod-shaped bacterial strains isolated from Heterorhabditis amazonensis entomopathogenic nematodes were characterized to determine their taxonomic position. 16S rRNA and gyrB gene sequences indicate that they belong to the class Gammaproteobacteria, family Morganellaceae and genus Photorhabdus, and that some of them are conspecifics. Two of them, APURET and JART, were selected for further molecular characterization using whole genome- and whole-proteome-based phylogenetic reconstructions and sequence comparisons. Phylogenetic reconstructions using whole genome and whole proteome sequences show that strains APURET and JART are closely related to Photorhabdus luminescens subsp. luminescens ATCC 29999T and to P. luminescens subsp. mexicana MEX47-22T. Moreover, digital DNA-DNA hybridization (dDDH) values between APURET and P. luminescens subsp. luminescens ATCC 29999T, APURET and P. luminescens subsp. mexicana MEX47-22T, and APURET and JART are 61.6, 61.2 and 64.1 %, respectively. These values are below the 70 % divergence threshold that delimits prokaryotic species. dDDH scores between JART and P. luminescens subsp. luminescens ATCC 29999T and between JART and P. luminescens subsp. mexicana MEX47-22T are 71.9 and 74.8 %, respectively. These values are within the 70 and 79 % divergence thresholds that delimit prokaryotic subspecies. Based on these genomic divergence values, APURET and JART represent two different taxa, for which we propose the names: Photorhabdus aballayi sp. nov. with APURET (=CCM 9236T =CCOS 2019T) as type strain and Photorhabdus luminescens subsp. venezuelensis subsp. nov. with JART (=CCM 9235T =CCOS 2021T) as type strain. Our study contributes to a better understanding of the biodiversity of an important bacterial group with enormous biotechnological and agricultural potential.
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Affiliation(s)
- Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
- Department of Biosciences, University Center for Research and Development, Chandigarh University, Gharuan, Mohali, 140413, Punjab, India
| | - Carlos Castaneda-Alvarez
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas. Universidad de Chile, Santiago, Chile
| | - Vladimir Půža
- Biology Centre CAS, Institute of Entomology, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic
| | - Ernesto San-Blas
- Instituto de Ciencias Agroalimentarias, Animales y Ambientales (ICA3), Universidad de O'Higgins, San Fernando, Chile
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Bhat AH, Machado RAR, Abolafia J, Askary TH, Půža V, Ruiz-Cuenca AN, Rana A, Sayed S, Al-Shuraym LA. Multigene Sequence-Based and Phenotypic Characterization Reveals the Occurrence of a Novel Entomopathogenic Nematode Species, Steinernema anantnagense n. sp. J Nematol 2023; 55:20230029. [PMID: 37455851 PMCID: PMC10341053 DOI: 10.2478/jofnem-2023-0029] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Indexed: 07/18/2023] Open
Abstract
Three entomopathogenic nematode populations were isolated from agricultural fields in the Anantnag district of Jammu and Kashmir (India). Sequences of multiple gene regions and phenotypic features show that they are conspecific and represent a novel species. Molecular and morphological features provided evidence for placing the new species into the "Kushidai" clade. Within this clade, analysis of sequence data of the internal transcribed spacer (ITS) gene, the D2D3 region of the 28S rRNA gene, the mitochondrial cytochrome oxidase I (mtCOI) gene, and the mitochondrial 12S (mt12S) gene depicted the novel species as a distinctive entity closely related to Steinernema akhursti, S. kushidai, and S. populi. Phylogenetic analyses also show that the new species is a sister species to S. akhursti, and these two species are closely related to S. kushidai and S. populi. Additionally, the new species does not mate or produce fertile progeny with any of the closely related species, reinforcing its uniqueness from a biological species concept standpoint. The new species is further characterized by the third-stage infective juveniles with almost straight bodies (0.7-0.8 mm length), poorly developed stoma and pharynx, and conoid-elongate tail (49-66 µm) with hyaline posterior part. Adult females are characterized by short and conoid tails bearing a short mucron in the first generation and long conoid tails with thin mucron in the second generation. Adult males have ventrally curved spicules in both generations. Moreover, the first-generation male has rounded manubrium, fusiform gubernaculum, conoid and slightly ventrally curved tails with minute mucron, and the second generation has rhomboid manubrium anteriorly ventrad bent, and tails with long and robust mucron. The morphological, morphometrical, molecular, and phylogenetic analyses support the new species status of this nematode, which is hereby described as Steinernema anantnagense n. sp. The bacterial symbiont associated with S. anantnagense n. sp. represents a novel species, closely related to Xenorhabdus japonica. These findings shed light on the diversity of entomopathogenic nematodes and their symbiotic bacteria, providing valuable information for future studies in this field.
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Affiliation(s)
- Aashaq Hussain Bhat
- Department of Biosciences and University Center for Research and Development, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ricardo A. R. Machado
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus “Las Lagunillas”, Jaén, Spain
| | - Tarique Hassan Askary
- Division of Entomology, Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Wadura Campus, Jammu and Kashmir, India
| | - Vladimír Půža
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 37005České Budějovice, Czech Republic
| | - Alba Nazaret Ruiz-Cuenca
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus “Las Lagunillas”, Jaén, Spain
| | - Aasha Rana
- Department of Zoology, Faculty of Basic and Applied Sciences, Madhav University, Pindwara (Sirohi), Rajasthan, 307026, India
| | - Samy Sayed
- Department of Economic Entomology and Pesticides, Faculty of Agriculture, Cairo University, 12613, Giza, Egypt
| | - Laila A. Al-Shuraym
- Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh11671, Saudi Arabia
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Castaneda-Alvarez C, Machado RAR, Morales-Montero P, Boss A, Muller A, Prodan S, Zamorano A, San-Blas E, Půža V, Aballay E. Photorhabdus antumapuensis sp. nov., a novel symbiotic bacterial species associated with Heterorhabditis atacamensis entomopathogenic nematodes. Int J Syst Evol Microbiol 2022; 72. [DOI: 10.1099/ijsem.0.005525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
One motile, Gram-negative, non-spore-forming and rod-shaped symbiotic bacterium, strain UCH-936T, was isolated from Heterorhabditis atacamensis nematodes. Results of biochemical, physiological, molecular and genomic analyses suggest that it represents a new species, which we propose to name Photorhabdus antumapuensis sp. nov. Digital DNA–DNA hybridization shows that strain UCH-936T is more closely related to
Photorhabdus kleinii
DSM 23513T, but shares solely 50.5 % similarity, which is below the 70% cut-off value that delimits species boundaries in bacteria. Phylogenetic reconstructions using whole-genome sequences show that strain UCH-936T forms a unique clade, suggesting its novel and distinct taxonomic status again. Similarly, comparative genomic analyses shows that the virulence factor flagella-related gene fleR, the type IV pili-related gene pilL and the vibriobactin-related gene vibE are present in the genome of strain UCH-936T but absent in the genomes of its closest relatives. Biochemically and physiologically, UCH-936T differs also from all closely related
Photorhabdus
species. Therefore, Photorhabdus antumapuensis sp. nov. is proposed as a new species with the type strain UCH-936T (CCCT 21.06T=CCM 9188T=CCOS 1991T).
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Affiliation(s)
- Carlos Castaneda-Alvarez
- Programa de Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Campus Sur Universidad de Chile, Santa Rosa 11315, La Pintana, Santiago, CP 8820808, Chile
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, P.O. Box 1004, Santiago, Chile
| | - Ricardo A. R. Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Patricia Morales-Montero
- Departamento de Ciencias Vegetales, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Macul, Santiago, Chile
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Anja Boss
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Arthur Muller
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Simona Prodan
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, P.O. Box 1004, Santiago, Chile
| | - Alan Zamorano
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, P.O. Box 1004, Santiago, Chile
| | - Ernesto San-Blas
- Instituto de Ciencias Agroalimentarias, Animales y Ambientales (ICA3), Universidad de O'Higgins, San Pedro, San José Province, Chile
| | - Vladimír Půža
- Laboratory of Entomopathogenic Nematodes, Institute of Entomology, Biology Centre CAS, Branišovská 31, České Budějovice, 370 05, Czechia
| | - Erwin Aballay
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, P.O. Box 1004, Santiago, Chile
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Muangpat P, Meesil W, Ngoenkam J, Teethaisong Y, Thummeepak R, Sitthisak S, Tandhavanant S, Chantratita N, Bode HB, Vitta A, Thanwisai A. Genome analysis of secondary metabolite‑biosynthetic gene clusters of Photorhabdus akhurstii subsp. akhurstii and its antibacterial activity against antibiotic-resistant bacteria. PLoS One 2022; 17:e0274956. [PMID: 36129957 PMCID: PMC9491552 DOI: 10.1371/journal.pone.0274956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/08/2022] [Indexed: 11/27/2022] Open
Abstract
Xenorhabdus and Photorhabdus can produce a variety of secondary metabolites with broad spectrum bioactivity against microorganisms. We investigated the antibacterial activity of Xenorhabdus and Photorhabdus against 15 antibiotic-resistant bacteria strains. Photorhabdus extracts had strong inhibitory the growth of Methicillin-resistant Staphylococcus aureus (MRSA) by disk diffusion. The P. akhurstii s subsp. akhurstii (bNN168.5_TH) extract showed lower minimum inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC). The interaction between either P. akhurstii subsp. akhurstii (bNN141.3_TH) or P. akhurstii subsp. akhurstii (bNN168.5_TH) or P. hainanensis (bNN163.3_TH) extract in combination with oxacillin determined by checkerboard assay exhibited partially synergistic interaction with fractional inhibitory concentration index (FICI) of 0.53. Time-killing assay for P. akhurstii subsp. akhurstii (bNN168.5_TH) extract against S. aureus strain PB36 significantly decreased cell viability from 105 CFU/ml to 103 CFU/ml within 30 min (P < 0.001, t-test). Transmission electron microscopic investigation elucidated that the bNN168.5_TH extract caused treated S. aureus strain PB36 (MRSA) cell membrane damage. The biosynthetic gene clusters of the bNN168.5_TH contained non-ribosomal peptide synthetase cluster (NRPS), hybrid NRPS-type l polyketide synthase (PKS) and siderophore, which identified potentially interesting bioactive products: xenematide, luminmide, xenortide A-D, luminmycin A, putrebactin/avaroferrin and rhizomide A-C. This study demonstrates that bNN168.5_TH showed antibacterial activity by disrupting bacterial cytoplasmic membrane and the draft genome provided insights into the classes of bioactive products. This also provides a potential approach in developing a novel antibacterial agent.
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Affiliation(s)
- Paramaporn Muangpat
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Wipanee Meesil
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Jatuporn Ngoenkam
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Yothin Teethaisong
- Faculty of Allied Health Sciences, Department of Biomedical Sciences, Burapha University, Chonburi, Thailand
- Research Unit for Sensor Inovation (RUSI), Burapha University, Chon Buri, Thailand
| | - Rapee Thummeepak
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Sutthirat Sitthisak
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
| | - Sarunporn Tandhavanant
- Faculty of Tropical Medicine, Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Narisara Chantratita
- Faculty of Tropical Medicine, Department of Microbiology and Immunology, Mahidol University, Bangkok, Thailand
| | - Helge B. Bode
- Molekulare Biotechnologie, Goethe Universität Frankfurt, Frankfurt am Main, Germany
- Department of Natural Products in Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Apichat Vitta
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
- Faculty of Sciences, Center of Excellence for Biodiversity, Naresuan University, Phitsanulok, Thailand
- Faculty of Medical Science, Centre of Excellence in Medical Biotechnology (CEMB), Naresuan University, Phitsanulok, Thailand
| | - Aunchalee Thanwisai
- Faculty of Medical Science, Department of Microbiology and Parasitology, Naresuan University, Phitsanulok, Thailand
- Faculty of Sciences, Center of Excellence for Biodiversity, Naresuan University, Phitsanulok, Thailand
- Faculty of Medical Science, Centre of Excellence in Medical Biotechnology (CEMB), Naresuan University, Phitsanulok, Thailand
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Booysen E, Malan AP, Dicks LM. Colour of Heterorhabditis zealandica-infected-Galleria mellonella dependent on the Photorhabdus symbiont, with two new nematode-symbiotic associations reported. J Invertebr Pathol 2022; 189:107729. [DOI: 10.1016/j.jip.2022.107729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/24/2022] [Accepted: 01/31/2022] [Indexed: 10/19/2022]
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Machado RAR, Bhat AH, Abolafia J, Shokoohi E, Fallet P, Turlings TCJ, Tarasco E, Půža V, Kajuga J, Yan X, Toepfer S. Steinernema Africanum n. Sp. (Rhabditida, Steinernematidae), a New Entomopathogenic Nematode Species Isolated in the Republic of Rwanda. J Nematol 2022; 54:20220049. [PMID: 36457370 PMCID: PMC9676676 DOI: 10.2478/jofnem-2022-0049] [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: 06/07/2022] [Indexed: 11/06/2022] Open
Abstract
Alternatives to hazardous insecticides are urgently needed for an environmentally friendly and effective management of insect pests. One such option is the use of entomopathogenic nematodes (EPN). To increase the availability of EPN with potential for biocontrol, we surveyed agricultural soils in the Republic of Rwanda and collected two Steinernema isolates. Initial molecular characterization showed that they represent a new species, for which we propose the name S. africanum n. sp. To describe this new species, we reconstructed phylogenetic relationships, calculated sequence similarity scores, characterized the nematodes at the morphological level, conducted crossing experiments, and isolated and characterized their symbiotic bacteria. At the molecular level, S. africanum n. sp. is closely related to S. litorale and S. weiseri. At the morphological level, S. africanum n. sp. differs from closely related species by the position of the nerve ring and also because the stoma and pharynx region is longer. The first-generation males have ventrally curved spicules with lanceolate manubrium and fusiform gubernaculum and the second-generation males have rounded manubrium and anteriorly hook-like gubernaculum. Steinernema africanum n. sp. does not mate or produce fertile progeny with any of the closely related species.
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Affiliation(s)
- Ricardo A. R. Machado
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus ‘Las Lagunillas’, Jaén, Spain
| | - Ebrahim Shokoohi
- Department of Plant Production, Soil Science and Agricultural Engineering, University of Limpopo, Sovenga, South Africa
| | - Patrick Fallet
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
- CABI Switzerland, Delémont, Switzerland
| | - Ted C. J. Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, Switzerland
| | - Eustachio Tarasco
- Department of Soil, Plant and Food Sciences, University of Bari “Aldo Moro”, Bari, Italy
| | - Vladimír Půža
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Joelle Kajuga
- Department of Crop Innovations and Technology Transfer, Rwanda Agriculture and Animal Resources Development Board, Kigali, Rwanda
| | - Xun Yan
- Innovative Institute for Plant Health, College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Stefan Toepfer
- CABI Switzerland, Delémont, Switzerland
- MARA-CABI Joint Laboratory for Biosafety, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Castaneda-Alvarez C, Prodan S, Zamorano A, San-Blas E, Aballay E. Xenorhabdus lircayensis sp. nov., the symbiotic bacterium associated with the entomopathogenic nematode Steinernema unicornum. Int J Syst Evol Microbiol 2021; 71. [PMID: 34898417 DOI: 10.1099/ijsem.0.005151] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Xenorhabdus is a symbiotic group of bacteria associated with entomopathogenic nematodes of the family Steinernematidae. Although the described Steirnernema species list is extensive, not all their symbiotic bacteria have been identified. One single motile, Gram-negative and non-spore-forming rod-shaped symbiotic bacterium, strain VLST, was isolated from the entomopathogenic nematode Steinernema unicornum. Analyses of the 16S rRNA gene determined that the VLST isolate belongs to the genus Xenorhabdus, and its closest related species is Xenorhabdus szentirmaii DSM 16338T (98.2 %). Deeper analyses using the whole genome for phylogenetic reconstruction indicate that VLST exhibits a unique clade in the genus. Genomic comparisons considering digital DNA-DNA hybridization (dDDH) values confirms this result, showing that the VLST values are distant enough from the 70 % threshold suggested for new species, sharing 30.7, 30.5 and 30.3 % dDDH with Xenorhabdus khoisanae MCB, Xenorhabdus koppenhoeferi DSM 18168T and Xenorhabdus miraniensis DSM 18168T, respectively, as the closest species. Detailed physiological, biochemical and chemotaxonomic tests of the VLST isolate reveal consistent differences from previously described Xenorhabdus species. Phylogenetic, physiological, biochemical and chemotaxonomic approaches show that VLST represents a new species of the genus Xenorhabdus, for which the name Xenorhabdus lircayensis sp. nov. (type strain VLST=CCCT 20.04T=DSM 111583T) is proposed.
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Affiliation(s)
- Carlos Castaneda-Alvarez
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, Chile.,Programa de Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Campus Sur Universidad de Chile, Santa Rosa 11315, La Pintana, Santiago, CP: 8820808, Chile
| | - Simona Prodan
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, Chile
| | - Alan Zamorano
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, Chile
| | - Ernesto San-Blas
- Instituto de Ciencias Agroalimentarias, Animales y Ambientales (ICA3), Universidad de O'Higgins, O'Higgins, Chile
| | - Erwin Aballay
- Departamento de Sanidad Vegetal, Facultad de Ciencias Agronómicas, Universidad de Chile, Chile
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Machado RA, Bhat AH, Abolafia J, Muller A, Bruno P, Fallet P, Arce CC, Turlings TC, Bernal JS, Kajuga J, Waweru B, Toepfer S. Multi-locus phylogenetic analyses uncover species boundaries and reveal the occurrence of two new entomopathogenic nematode species, Heterorhabditis ruandica n. sp. and Heterorhabditis zacatecana n. sp. J Nematol 2021; 53:e2021-89. [PMID: 34790901 PMCID: PMC8588743 DOI: 10.21307/jofnem-2021-089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Indexed: 11/17/2022] Open
Abstract
Species of the nematode genus Heterorhabditis are important biological control agents against agricultural pests. The taxonomy of this group is still unclear as it currently relies on phylogenetic reconstructions based on a few genetic markers with little resolutive power, specially of closely related species. To fill this knowledge gap, we sequenced several phylogenetically relevant genetic loci and used them to reconstruct phylogenetic trees, to calculate sequence similarity scores, and to determine signatures of species- and population-specific genetic polymorphism. In addition, we revisited the current literature related to the description, synonymisation, and declaration as species inquirendae of Heterorhabditis species to compile taxonomically relevant morphological and morphometric characters, characterized new nematode isolates at the morphological and morphometrical level, and conducted self-crossing and cross-hybridization experiments. The results of this study show that the sequences of the mitochondrial cytochrome C oxidase subunit I (COI) gene provide better phylogenetic resolutive power than the sequences of nuclear rRNA genes and that this gene marker can phylogenetically resolve closely related species and even populations of the same species with high precision. Using this gene marker, we found two new species, Heterorhabditis ruandica n. sp. and Heterorhabditis zacatecana n. sp. A detailed characterization of these species at the morphological and morphometric levels and nematode reproduction assays revealed that the threshold for species delimitation in this genus, using COI sequences, is 97% to 98%. Our study illustrates the importance of rigorous morphological and morphometric characterization and multi-locus sequencing for the description of new species within the genus Heterorhabditis, serves to clarify the phylogenetic relationships of this important group of biological control agents, and can inform future species descriptions to advance our efforts towards developing more tools for sustainable and environmentally friendly agriculture.
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Affiliation(s)
- Ricardo A.R. Machado
- Experimental Biology Research Group. Institute of Biology. Faculty of Sciences. University of Neuchâtel. Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Department of Zoology, Government Degree College. Billawar-184204, Kathua, Jammu, Jammu and Kashmir, India
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus ‘Las Lagunillas’ s/n, Edificio B3, 23071 Jaén, Spain
| | - Arthur Muller
- Experimental Biology Research Group. Institute of Biology. Faculty of Sciences. University of Neuchâtel. Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Pamela Bruno
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Patrick Fallet
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Carla C.M. Arce
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Ted C.J. Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology. Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Julio S. Bernal
- Department of Entomology, Texas A&M University, College Station, TX
| | - Joelle Kajuga
- Department of Crop Innovations & Technology Transfer. Rwanda Agriculture and Animal Resources Development Board, 5016 Kigali-Rwanda
| | - Bancy Waweru
- Department of Crop Innovations & Technology Transfer. Rwanda Agriculture and Animal Resources Development Board, 5016 Kigali-Rwanda
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11
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Machado RAR, Somvanshi VS, Muller A, Kushwah J, Bhat CG. Photorhabdus hindustanensis sp. nov., Photorhabdus akhurstii subsp. akhurstii subsp. nov. , and Photorhabdus akhurstii subsp. bharatensis subsp. nov. , isolated from Heterorhabditis entomopathogenic nematodes. Int J Syst Evol Microbiol 2021; 71. [PMID: 34524954 DOI: 10.1099/ijsem.0.004998] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Two Gram-negative, rod-shaped bacteria, H1T and H3T, isolated from the digestive tract of Heterorhabditis entomopathogenic nematodes were biochemically and molecularly characterized to determine their taxonomic positions. The 16S rRNA gene sequences of these strains indicate that they belong to the Gammaproteobacteria, to the family Morganellaceae, and to the Photorhabdus genus. Deeper analyses using whole genome-based phylogenetic reconstructions show that strains H1T and H3T are closely related to P. akhurstii DSM 15138T, to P. hainanensis DSM 22397T, and to P. namnaonensis PB45.5T. In silico genomic comparisons confirm these observations and show that strain H1T shares 70.6, 66.8, and 63.5 % digital DNA-DNA hybridization (dDDH) with P. akhurstii DSM 15138T, P. hainanensis DSM 22397T, and P. namnaonensis PB45.5T, respectively, and that strain H3T shares 76.6, 69.4, and 59.2 % dDDH with P. akhurstii DSM 15138T, P. hainanensis DSM 22397T, and P. namnaonensis PB45.5T, respectively. Physiological and biochemical characterization reveals that these two strains differ from most of the validly described Photorhabdus species and from their more closely related taxa. Given the clear phylogenetic separations, that the threshold to discriminate species and subspecies is 70 and 79% dDDH, respectively, and that strains H1T and H3T differ physiologically and biochemically from their more closely related taxa, we propose to classify H1T and H3T into new taxa as follows: H3T as a new subspecies within the species P. akhurstii, and H1T as a new species within the Photorhabdus genus, in spite that H1T shares 70.6 % dDDH with P. akhurstii DSM 15138T, score that is slightly higher than the 70 % threshold that delimits species boundaries. The reason for this is that H1T and P. akhurstii DSM 15138T cluster apart in the phylogenetic trees and that dDDH scores between strain H1T and other P. akhurstii strains are lower than 70 %. Hence, the following names are proposed: Photorhabdus hindustanensis sp. nov. with the type strain H1T (=IARI-SGMG3T,=KCTC 82683T=CCM 9150T=CCOS 1975T) and P. akhurstii subsp. bharatensis subsp. nov. with the type strain H3T (=IARI-SGHR2T=KCTC 82684T=CCM 9149T=CCOS 1976T). These propositions automatically create P. akhurstii subsp. akhurstii subsp. nov. with DSM 15138T as the type strain (currently classified as P. akhurstii).
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Affiliation(s)
- Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Vishal S Somvanshi
- Division of Nematology, Indian Council of Agricultural Research, Indian Agricultural Research Institute (ICAR-IARI), New Delhi, India
| | - Arthur Muller
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Jyoti Kushwah
- Division of Nematology, Indian Council of Agricultural Research, Indian Agricultural Research Institute (ICAR-IARI), New Delhi, India
| | - Chaitra G Bhat
- Division of Nematology, Indian Council of Agricultural Research, Indian Agricultural Research Institute (ICAR-IARI), New Delhi, India
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Photorhabdus spp.: An Overview of the Beneficial Aspects of Mutualistic Bacteria of Insecticidal Nematodes. PLANTS 2021; 10:plants10081660. [PMID: 34451705 PMCID: PMC8401807 DOI: 10.3390/plants10081660] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 11/17/2022]
Abstract
The current approaches to sustainable agricultural development aspire to use safer means to control pests and pathogens. Photorhabdus bacteria that are insecticidal symbionts of entomopathogenic nematodes in the genus Heterorhabditis can provide such a service with a treasure trove of insecticidal compounds and an ability to cope with the insect immune system. This review highlights the need of Photorhabdus-derived insecticidal, fungicidal, pharmaceutical, parasiticidal, antimicrobial, and toxic materials to fit into current, or emerging, holistic strategies, mainly for managing plant pests and pathogens. The widespread use of these bacteria, however, has been slow, due to cost, natural presence within the uneven distribution of their nematode partners, and problems with trait stability during in vitro culture. Yet, progress has been made, showing an ability to overcome these obstacles via offering affordable mass production and mastered genome sequencing, while detecting more of their beneficial bacterial species/strains. Their high pathogenicity to a wide range of arthropods, efficiency against diseases, and versatility, suggest future promising industrial products. The many useful properties of these bacteria can facilitate their integration with other pest/disease management tactics for crop protection.
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13
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Antifungal activity of different Xenorhabdus and Photorhabdus species against various fungal phytopathogens and identification of the antifungal compounds from X. szentirmaii. Appl Microbiol Biotechnol 2021; 105:5517-5528. [PMID: 34250572 DOI: 10.1007/s00253-021-11435-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 10/20/2022]
Abstract
Xenorhabdus and Photorhabdus spp. are enteric bacterial symbionts of Steinernema and Heterorhabditis nematodes, respectively. These bacteria produce an extensive set of natural products (NPs) with antibacterial, antifungal, antiprotozoal, insecticidal, or other bioactivities when vectored into insect hemocoel by nematodes. We assessed the in vitro activity of different Xenorhabdus and Photorhabdus cell-free supernatants against important fungal phytopathogens, viz., Cryphonectria parasitica, Fusarium oxysporum, Rhizoctonia solani, and Sclerotinia sclerotiorum and identified the bioactive antifungal compound/s present in the most effective bacterial supernatant using the easyPACId (easy promoter-activated compound identification) approach against chestnut blight C. parasitica. Our data showed that supernatants from Xenorhabdus species were comparatively more effective than extracts from Photorhabdus in suppressing the fungal pathogens; among the bacteria assessed, Xenorhabdus szentirmaii was the most effective species against all tested phytopathogens especially against C. parasitica. Subsequent analysis revealed fabclavines as antifungal bioactive compounds in X. szentirmaii, generated by a polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) hybrid system. Fabclavines are broad-spectrum, heat-stable NPs that have great potential as biological control compounds against fungal plant pathogens. More studies are needed to assess the potential phytotoxicity of these compounds and their effects on non-target organisms before commercialization. KEY POINTS: • Chemical fungicides have toxic effects on humans and other non-target organisms. • Alternatives with novel modes of action to supplant current fungicide are needed. • A novel bioactive antifungal compound from Xenorhabdus szentirmaii was identified.
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14
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Hill V, Kuhnert P, Erb M, Machado RAR. Identification of Photorhabdus symbionts by MALDI-TOF MS. MICROBIOLOGY-SGM 2021; 166:522-530. [PMID: 32301690 DOI: 10.1099/mic.0.000905] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Species of the bacterial genus Photorhabus live in a symbiotic relationship with Heterorhabditis entomopathogenic nematodes. Besides their use as biological control agents against agricultural pests, some Photorhabdus species are also a source of natural products and are of medical interest due to their ability to cause tissue infections and subcutaneous lesions in humans. Given the diversity of Photorhabdus species, rapid and reliable methods to resolve this genus to the species level are needed. In this study, we evaluated the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of Photorhabdus species. To this end, we established a collection of 54 isolates consisting of type strains and multiple field strains that belong to each of the validly described species and subspecies of this genus. Reference spectra for the strains were generated and used to complement a currently available database. The extended reference database was then used for identification based on the direct transfer sample preparation method and the protein fingerprint of single colonies. High-level discrimination of distantly related species was observed. However, lower discrimination was observed with some of the most closely related species and subspecies. Our results therefore suggest that MALDI-TOF MS can be used to correctly identify Photorhabdus strains at the genus and species level, but has limited resolution power for closely related species and subspecies. Our study demonstrates the suitability and limitations of MALDI-TOF-based identification methods for assessment of the taxonomic position and identification of Photorhabdus isolates.
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Affiliation(s)
- Virginia Hill
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Switzerland.,Institute of Plant Sciences, University of Bern, Switzerland
| | - Peter Kuhnert
- Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Switzerland
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, Switzerland
| | - Ricardo A R Machado
- Experimental Biology Research Group, University of Neuchatel, Switzerland.,Institute of Plant Sciences, University of Bern, Switzerland
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Bhat AH, Chaubey AK, Shokoohi E, Machado RAR. Molecular and Phenotypic Characterization of Heterorhabditis indica (Nematoda: Rhabditida) Nematodes Isolated During a Survey of Agricultural Soils in Western Uttar Pradesh, India. Acta Parasitol 2021; 66:236-252. [PMID: 32970280 DOI: 10.1007/s11686-020-00279-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 08/31/2020] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Entomopathogenic nematodes (EPNs) are important biocontrol agents of insect pests. To increase the availability of locally adapted entomopathogenic nematode isolates for biocontrol programs, a survey of several agricultural soils in Western Uttar Pradesh, India was conducted. MATERIALS AND METHODS Eight hundred and sixty soil samples from the districts Meerut, Bulandshahr, Baghpat, and Bijnor were collected and examined for the presence of entomopathogenic nematodos using the "Galleria baiting method". Steinernema and Heterorhabditis nematodes were recovered. The isolated Heterorhabditis nematodes were molecularly, and morphologically characterized, and their biocontrol potential was evaluated against Spodoptera litura. Finally, the geographical distribution of entomopathogenic nematodes was studied based on the analysis of ITS GenBank records. RESULTS A small proportion of the collected soil samples were positive for Heterorhabditis and Steinernema nematodes. Twelve soil samples were positive for the presence of Heterorhabditis nematodes, and 29 samples were positive for Steinernema. The Heterorhabditis nematodes were identified as Heterorhabditis indica based on morphological, morphometrical and molecular analyses. No other species of Heterorhabditis were isolated from the soil samples analyzed, suggesting that this species is dominant in the western part of Uttar Pradesh, India. The morphology of the nematode isolates was somewhat similar to the morphology of the H. indica isolate used for the original description of this species, with a notable exception mucrons were present in the hermaphrodite and female specimens we collected, but this structure was not observed in the specimens used for the original description of the species. Principal component analyses (PCA) show small inter- and intraspecific morphological variability between the nematodes species of the "Indica" clade. The insecticide properties of one isolate, CH7, were evaluated against Spodoptera litura, and the results show that this isolate effectively killed this pest under laboratory conditions, demonstrating its potential as a biocontrol agent. CONCLUSION This study sets the basis for establishing new biocontrol agents to be used in future pest management programs in India.
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Affiliation(s)
- Aashaq Hussain Bhat
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, 250004, India.
- Department of Zoology, Government Degree College Billawar-184204, University of Jammu, Billawar, Jammu, Jammu and Kashmir, India.
| | - Ashok Kumar Chaubey
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, 250004, India
| | - Ebrahim Shokoohi
- Green Biotechnologies Research Centre of Excellence, University of Limpopo, Private Bag X1106, Sovenga, 0727, Republic of South Africa
| | - Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchatel, 2000, Neuchatel, Switzerland
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16
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Machado RAR, Muller A, Ghazal SM, Thanwisai A, Pagès S, Bode HB, Hussein MA, Khalil KM, Tisa LS. Photorhabdus heterorhabditis subsp. aluminescens subsp. nov., Photorhabdus heterorhabditis subsp. heterorhabditis subsp. nov., Photorhabdus australis subsp. thailandensis subsp. nov., Photorhabdus australis subsp. australis subsp. nov., and Photorhabdus aegyptia sp. nov. isolated from Heterorhabditis entomopathogenic nematodes. Int J Syst Evol Microbiol 2021; 71. [PMID: 33464198 DOI: 10.1099/ijsem.0.004610] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Three Gram-stain-negative, rod-shaped, non-spore-forming bacteria, BA1T, Q614T and PB68.1T, isolated from the digestive system of Heterorhabditis entomopathogenic nematodes, were biochemically and molecularly characterized to clarify their taxonomic affiliations. The 16S rRNA gene sequences of these strains suggest that they belong to the Gammaproteobacteria, to the family Morganellacea, and to the genus Photorhabdus. Deeper analyses using whole genome-based phylogenetic reconstructions suggest that BA1T is closely related to Photorhabdus akhursti, that Q614T is closely related to Photorhabdus heterorhabditis, and that PB68.1T is closely related to Photorhabdus australis. In silico genomic comparisons confirm these observations: BA1T and P. akhursti 15138T share 68.8 % digital DNA-DNA hybridization (dDDH), Q614T and P. heterorhabditis SF41T share 75.4 % dDDH, and PB68.1T and P. australis DSM 17609T share 76.6 % dDDH. Physiological and biochemical characterizations reveal that these three strains also differ from all validly described Photorhabdus species and from their more closely related taxa, contrary to what was previously suggested. We therefore propose to classify BA1T as a new species within the genus Photorhabdus, Q614T as a new subspecies within P. heterorhabditis, and PB68.1T as a new subspecies within P. australis. Hence, the following names are proposed for these strains: Photorhabdus aegyptia sp. nov. with the type strain BA1T(=DSM 111180T=CCOS 1943T=LMG 31957T), Photorhabdus heterorhabditis subsp. aluminescens subsp. nov. with the type strain Q614T (=DSM 111144T=CCOS 1944T=LMG 31959T) and Photorhabdus australis subsp. thailandensis subsp. nov. with the type strain PB68.1T (=DSM 111145T=CCOS 1942T). These propositions automatically create Photorhabdus heterorhabditis subsp. heterorhabditis subsp. nov. with SF41T as the type strain (currently classified as P. heterorhabditis) and Photorhabdus australis subsp. australis subsp. nov. with DSM17609T as the type strain (currently classified as P. australis).
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Affiliation(s)
- Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
| | - Arthur Muller
- Experimental Biology Research Group, Institute of Biology. University of Neuchâtel, Neuchâtel, Switzerland
| | - Shimaa M Ghazal
- Genetics and Cytology Department, Genetic Engineering and Biotechnology Division, National Research Center, Cairo, Egypt.,Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire, USA
| | - Aunchalee Thanwisai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Sylvie Pagès
- INRAe, Université de Montpellier, UMR1333-DGIMI, 34095 Montpellier Cedex 05, France
| | - Helge B Bode
- Molekulare Biotechnologie, Fachbereich Biowissenschaften & Buchmann Institute for Molecular Life Sciences (BMLS), Goethe-Universität Frankfurt am Main & Senckenberg Gesellschaft für Naturforschung, Frankfurt, Germany
| | - Mona A Hussein
- Department of Pests and Plant Protection, Agricultural and Biological Division, National Research Centre, Dokki, Cairo, Egypt
| | - Kamal M Khalil
- Genetics and Cytology Department, Genetic Engineering and Biotechnology Division, National Research Center, Cairo, Egypt
| | - Louis S Tisa
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, USA
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17
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Bruno P, Machado RAR, Glauser G, Köhler A, Campos-Herrera R, Bernal J, Toepfer S, Erb M, Robert CAM, Arce CCM, Turlings TCJ. Entomopathogenic nematodes from Mexico that can overcome the resistance mechanisms of the western corn rootworm. Sci Rep 2020; 10:8257. [PMID: 32427834 PMCID: PMC7237494 DOI: 10.1038/s41598-020-64945-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/28/2020] [Indexed: 12/30/2022] Open
Abstract
Natural enemies of herbivores are expected to adapt to the defence strategies of their preys or hosts. Such adaptations may also include their capacity to cope with plant metabolites that herbivores sequester as a defence. In this study, we evaluated the ability of Mexican entomopathogenic nematodes (EPN) to resist benzoxazinoids that are sequestered from maize roots by the western corn rootworm (WCR, Diabrotica virgifera virgifera; Coleoptera: Chrysomelidae), an important maize pest in America and Europe. From maize fields throughout Mexico, we retrieved 40 EPN isolates belonging to five different species, with a majority identified as Heterorhabditis bacteriophora. In the laboratory, all nematodes readily infected non-sequestering larvae of the banded cucumber beetle (D. balteata), while infectivity varied strongly for WCR larvae. While some H. bacteriophora isolates seemed negatively affected by benzoxazinoids, most showed to be resistant. Thus, EPN from Mexican maize fields can cope with these plant defence metabolites, but the results also indicate that WCR larvae possess other mechanisms that help to resist EPN. This work contributes to a better understanding of the capacity of herbivore natural enemies to resist plant defence metabolites. Furthermore, it identifies several benzoxazinoid-resistant EPN isolates that may be used to control this important maize pest.
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Affiliation(s)
- Pamela Bruno
- Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | | | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland
| | - Angela Köhler
- Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland
- Friedrich Schiller University Jena, Jena, Germany
| | - Raquel Campos-Herrera
- Instituto de Ciencias de la Vid y del Vino (Universidad de La Rioja, CSIC, Gobierno de La Rioja), Logroño, La Rioja, Spain
| | - Julio Bernal
- Department of Entomology, Texas A&M University, Texas, USA
| | - Stefan Toepfer
- CABI, c/o Plant Protection and Soil Conservation Directorate, Hódmezővásárhely, Hungary
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | - Carla C M Arce
- Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland.
| | - Ted C J Turlings
- Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Emile-Argand 11, 2000, Neuchâtel, Switzerland.
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18
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Engineering bacterial symbionts of nematodes improves their biocontrol potential to counter the western corn rootworm. Nat Biotechnol 2020; 38:600-608. [PMID: 32066956 DOI: 10.1038/s41587-020-0419-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 01/10/2020] [Indexed: 01/18/2023]
Abstract
The western corn rootworm (WCR) decimates maize crops worldwide. One potential way to control this pest is treatment with entomopathogenic nematodes (EPNs) that harbor bacterial symbionts that are pathogenic to insects. However, WCR larvae sequester benzoxazinoid secondary metabolites that are produced by maize and use them to increase their resistance to the nematodes and their symbionts. Here we report that experimental evolution and selection for bacterial symbionts that are resistant to benzoxazinoids improve the ability of a nematode-symbiont pair to kill WCR larvae. We isolated five Photorhabdus symbionts from different nematodes and increased their benzoxazinoid resistance through experimental evolution. Benzoxazinoid resistance evolved through multiple mechanisms, including a mutation in the aquaporin-like channel gene aqpZ. We reintroduced benzoxazinoid-resistant Photorhabdus strains into their original EPN hosts and identified one nematode-symbiont pair that was able to kill benzoxazinoid-sequestering WCR larvae more efficiently. Our results suggest that modification of bacterial symbionts might provide a generalizable strategy to improve biocontrol of agricultural pests.
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Sajnaga E, Kazimierczak W. Evolution and taxonomy of nematode-associated entomopathogenic bacteria of the genera Xenorhabdus and Photorhabdus: an overview. Symbiosis 2020. [DOI: 10.1007/s13199-019-00660-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AbstractEntomopathogenic bacteria from the genera Photorhabdus and Xenorhabdus are closely related Gram-negative bacilli from the family Enterobacteriaceae (γ-Proteobacteria). They establish obligate mutualistic associations with soil nematodes from the genera Steinernema and Heterorhabditis to facilitate insect pathogenesis. The research of these two bacterial genera is focused mainly on their unique interactions with two different animal hosts, i.e. nematodes and insects. So far, studies of the mutualistic bacteria of nematodes collected from around the world have contributed to an increase in the number of the described Xenorhabdus and Photorhabdus species. Recently, the classification system of entomopatogenic nematode microsymbionts has undergone profound revision and now 26 species of the genus Xenorhabdus and 19 species of the genus Photorhabdus have been identified. Despite their similar life style and close phylogenetic origin, Photorhabdus and Xenorhabdus bacterial species differ significantly in e.g. the nematode host range, symbiotic strategies for parasite success, and arrays of released antibiotics and insecticidal toxins. As the knowledge of the diversity of entomopathogenic nematode microsymbionts helps to enable the use thereof, assessment of the phylogenetic relationships of these astounding bacterial genera is now a major challenge for researchers. The present article summarizes the main information on the taxonomy and evolutionary history of Xenorhabdus and Photorhabdus, entomopathogenic nematode symbionts.
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