Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America
Abstract Background Heterorhabditis are important biological control agents in agriculture. Two Heterorhabditis populations, S8 and S10, were isolated from agricultural soils in the United States of America. Molecular analyses, based on mitochondrial and nuclear genes, showed that these populations...
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BMC
2025-03-01
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| Series: | Parasites & Vectors |
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| Online Access: | https://doi.org/10.1186/s13071-025-06702-5 |
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| author | Ricardo A. R. Machado Joaquín Abolafia María-Cristina Robles Alba N. Ruiz-Cuenca Aashaq Hussain Bhat Ebrahim Shokoohi Vladimír Půža Xi Zhang Matthias Erb Christelle A. M. Robert Bruce Hibbard |
| author_facet | Ricardo A. R. Machado Joaquín Abolafia María-Cristina Robles Alba N. Ruiz-Cuenca Aashaq Hussain Bhat Ebrahim Shokoohi Vladimír Půža Xi Zhang Matthias Erb Christelle A. M. Robert Bruce Hibbard |
| author_sort | Ricardo A. R. Machado |
| collection | DOAJ |
| description | Abstract Background Heterorhabditis are important biological control agents in agriculture. Two Heterorhabditis populations, S8 and S10, were isolated from agricultural soils in the United States of America. Molecular analyses, based on mitochondrial and nuclear genes, showed that these populations are conspecific and represent a novel species of the “Bacteriophora” clade. This species was named Heterorhabditis americana n. sp. and is described in this study. Methods To describe H. americana n. sp., we carried out phylogenetic reconstructions using multiple genes, characterized their morphology, conducted self-crossing and cross-hybridization experiments, and isolated and identified their symbiotic bacteria. Results Heterorhabditis americana n. sp. is molecularly and morphologically similar to H. georgiana. Morphological differences between the males of H. americana n. sp. and H. georgiana include variations in the excretory pore position, the gubernaculum size, the gubernaculum-to-spicule length ratio, the tail length, and the body diameter. Infective juveniles (IJs) of H. americana n. sp. differ from H. georgiana IJs because H. americana n. sp. IJs have an invisible bacterial cell pouch posterior to the cardia and a small posterior phasmid, whereas H. georgiana IJs have a visible bacterial cell pouch and an inconspicuous phasmid. Hermaphrodites of H. americana n. sp. and H. georgiana are differentiated by the body length, the nerve ring distance from the anterior end, the excretory pore distance from the anterior end, the anal body diameter, and the c′ ratio. Females of H. americana n. sp. can be differentiated from H. georgiana females by the anal body diameter and the c′ ratio. Reproductive isolation was confirmed, as H. americana n. sp. does not produce viable offspring with any of the species of the “Bacteriophora” clade. Heterorhabditis americana n. sp. is associated with the symbiotic bacterium Photorhabdus kleinii. Conclusions Based on the observed morphological and morphometric differences, the distinct phylogenetic placement, and the reproductive isolation, the nematode isolates S8 and S10 represent a novel species, which we named Heterorhabditis americana n. sp. This study provides a detailed characterization of this novel species, contributing to enhancing our knowledge of species diversity and evolutionary relationships of the Heterorhabditis genus. Graphical Abstract |
| format | Article |
| id | doaj-art-54d7b7f2702a44a48e3f726371a2f8e0 |
| institution | DOAJ |
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| language | English |
| publishDate | 2025-03-01 |
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| spelling | doaj-art-54d7b7f2702a44a48e3f726371a2f8e02025-08-20T03:01:23ZengBMCParasites & Vectors1756-33052025-03-0118112810.1186/s13071-025-06702-5Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North AmericaRicardo A. R. Machado0Joaquín Abolafia1María-Cristina Robles2Alba N. Ruiz-Cuenca3Aashaq Hussain Bhat4Ebrahim Shokoohi5Vladimír Půža6Xi Zhang7Matthias Erb8Christelle A. M. Robert9Bruce Hibbard10Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of NeuchâtelDepartamento de Biología Animal, Biología Vegetal y Ecología, Universidad de JaénDepartamento de Biología Animal, Biología Vegetal y Ecología, Universidad de JaénDepartamento de Biología Animal, Biología Vegetal y Ecología, Universidad de JaénExperimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of NeuchâtelDepartment of Biochemistry, Microbiology and Biotechnology, University of LimpopoInstitute of Entomology, Biology Centre of the Czech Academy of Sciences, CASInstitute of Plant Sciences, University of BernInstitute of Plant Sciences, University of BernInstitute of Plant Sciences, University of BernPlant Genetics Research Unit, United States Department of Agriculture (USDA)-Agricultural Research ServiceAbstract Background Heterorhabditis are important biological control agents in agriculture. Two Heterorhabditis populations, S8 and S10, were isolated from agricultural soils in the United States of America. Molecular analyses, based on mitochondrial and nuclear genes, showed that these populations are conspecific and represent a novel species of the “Bacteriophora” clade. This species was named Heterorhabditis americana n. sp. and is described in this study. Methods To describe H. americana n. sp., we carried out phylogenetic reconstructions using multiple genes, characterized their morphology, conducted self-crossing and cross-hybridization experiments, and isolated and identified their symbiotic bacteria. Results Heterorhabditis americana n. sp. is molecularly and morphologically similar to H. georgiana. Morphological differences between the males of H. americana n. sp. and H. georgiana include variations in the excretory pore position, the gubernaculum size, the gubernaculum-to-spicule length ratio, the tail length, and the body diameter. Infective juveniles (IJs) of H. americana n. sp. differ from H. georgiana IJs because H. americana n. sp. IJs have an invisible bacterial cell pouch posterior to the cardia and a small posterior phasmid, whereas H. georgiana IJs have a visible bacterial cell pouch and an inconspicuous phasmid. Hermaphrodites of H. americana n. sp. and H. georgiana are differentiated by the body length, the nerve ring distance from the anterior end, the excretory pore distance from the anterior end, the anal body diameter, and the c′ ratio. Females of H. americana n. sp. can be differentiated from H. georgiana females by the anal body diameter and the c′ ratio. Reproductive isolation was confirmed, as H. americana n. sp. does not produce viable offspring with any of the species of the “Bacteriophora” clade. Heterorhabditis americana n. sp. is associated with the symbiotic bacterium Photorhabdus kleinii. Conclusions Based on the observed morphological and morphometric differences, the distinct phylogenetic placement, and the reproductive isolation, the nematode isolates S8 and S10 represent a novel species, which we named Heterorhabditis americana n. sp. This study provides a detailed characterization of this novel species, contributing to enhancing our knowledge of species diversity and evolutionary relationships of the Heterorhabditis genus. Graphical Abstracthttps://doi.org/10.1186/s13071-025-06702-5Entomopathogenic nematodesBiocontrol agentsSpecies descriptionNematode morphologyPhylogeneticsTaxonomy |
| spellingShingle | Ricardo A. R. Machado Joaquín Abolafia María-Cristina Robles Alba N. Ruiz-Cuenca Aashaq Hussain Bhat Ebrahim Shokoohi Vladimír Půža Xi Zhang Matthias Erb Christelle A. M. Robert Bruce Hibbard Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America Parasites & Vectors Entomopathogenic nematodes Biocontrol agents Species description Nematode morphology Phylogenetics Taxonomy |
| title | Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America |
| title_full | Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America |
| title_fullStr | Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America |
| title_full_unstemmed | Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America |
| title_short | Description of Heterorhabditis americana n. sp. (Rhabditida, Heterorhabditidae), a new entomopathogenic nematode species isolated in North America |
| title_sort | description of heterorhabditis americana n sp rhabditida heterorhabditidae a new entomopathogenic nematode species isolated in north america |
| topic | Entomopathogenic nematodes Biocontrol agents Species description Nematode morphology Phylogenetics Taxonomy |
| url | https://doi.org/10.1186/s13071-025-06702-5 |
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