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Menon AG, Bhaskar H, Gopal KS, M R, Subramanian SM. Symbiotic and Nonsymbiotic Bacteria Associated With the Entomo-Pathogenic Nematode, Heterorhabditis spp (Rhabditida: Heterorhabditidae) From South India. J Basic Microbiol 2024:e2400108. [PMID: 39239913 DOI: 10.1002/jobm.202400108] [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: 03/10/2024] [Revised: 08/02/2024] [Accepted: 08/24/2024] [Indexed: 09/07/2024]
Abstract
Sixteen isolates of bacteria obtained from the entomopathogenic nematode (Heterorhabditis sp.) infected cadavers of Galleria mellonella larvae were identified following phenotypic characterization and molecular analysis of 16S rRNA. Two isolates were identified as the symbiotic bacterium, Photothabdus luminescens, while 14 other isolates were represented by nine species of nonsymbiotic bacteria viz., Stenotrophomonas maltophilia, Alcaligenes aquatilis, Brevundimonas diminuta, Brucella pseudointermedia, Ochrobactrum sp., Brucella pseudogrignonensis, Brucella anthropic, Pseudomonas azatoformans and Pseudomonas lactis. The phylogenetic analysis confirmed the evolutionary relationship between P. luminescens and Pseudomonas spp. The study also found a close relationship among the nonsymbiotic bacteria such as A. aquatilis, B. diminuta, Ochrobactrum sp., and Brucella spp. P. luminescens has been documented for its insecticidal effects against a wide range of insects. The two local isolates obtained in this study may be explored for their biocontrol potential against major pests of the region. Further, the association of nonsymbiotic bacteria with the EPN may be investigated.
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Affiliation(s)
- Athira G Menon
- Department of Agricultural Entomology, College of Agriculture, Kerala Agricultural University, Thrissur, Kerala, India
| | - Haseena Bhaskar
- Department of Agricultural Entomology, College of Agriculture, Kerala Agricultural University, Thrissur, Kerala, India
| | - K Surendra Gopal
- Department of Agricultural Microbiology, College of Agriculture, Kerala Agricultural University, Thrissur, Kerala, India
| | - Rajkumar M
- Crop Protection, ICAR-Central Plantation Crops Research Institute, Kudlu, Kerala, India
| | - Smitha M Subramanian
- Department of Agricultural Entomology, College of Agriculture, Kerala Agricultural University, Thrissur, Kerala, India
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Bhat AH, Machado RAR, Abolafia J, Ruiz-Cuenca AN, Askary TH, Ameen F, Dass WM. Taxonomic and molecular characterization of a new entomopathogenic nematode species, Heterorhabditis casmirica n. sp., and whole genome sequencing of its associated bacterial symbiont. Parasit Vectors 2023; 16:383. [PMID: 37880744 PMCID: PMC10598981 DOI: 10.1186/s13071-023-05990-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 09/29/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND Nematodes of the genus Heterorhabditis are important biocontrol agents as they form a lethal combination with their symbiotic Photorhabdus bacteria against agricultural insect pests. This study describes a new species of Heterorhabditis. METHODS Six Heterorhabditis nematode populations were recovered from agricultural soils in Jammu and Kashmir, India. An initial examination using mitochondrial and nuclear genes showed that they belong to a new species. To describe this new species, a variety of analyses were conducted, including reconstructing phylogenetic relationships based on multiple genes, characterizing the nematodes at the morphological and morphometric levels, performing self-crossing and cross-hybridization experiments, and isolating and characterizing their symbiotic bacteria. RESULTS The newly discovered species, Heterorhabditis casmirica n. sp., shares 94% mitochondrial cytochrome C oxidase subunit I gene (COI) sequence identity with Heterorhabditis bacteriophora and Heterorhabditis ruandica, and 93% with Heterorhabditis zacatecana. Morphologically, it differs from H. bacteriophora in its infective juvenile phasmids (present vs. inconspicuous) and bacterial pouch visibility in the ventricular portion of the intestine (invisible vs. visible); genital papilla 1 (GP1) position (at manubrium level vs. more anterior), and in its b ratio (body length/neck length), c ratio (tail length/bulb width), and D% [(excretory pore/neck length) × 100]. Other morphological differences include anterior end to the nerve ring distance (77-100 vs. 121-130 μm), V% [(anterior end of vulva/body length) × 100] (46-57 vs. 41-47) in hermaphroditic females; rectum size (slightly longer than the anal body diameter vs. about three times longer), phasmids (smaller vs. inconspicuous), body length (0.13-2.0 vs. 0.32-0.39 mm), body diameter (73-150 vs. 160-220 μm), anterior end to the excretory pore distance (135-157 vs. 174-214 μm), and demanian ratios in amphimictic females. Morphological differences with H. ruandica and H. zacatecana were also observed. Furthermore, H. casmirica n. sp. did not mate or produce fertile progeny with other Heterorhabditis nematodes reported from India. It was also discovered that H. casmirica n. sp. is associated with Photorhabdus luminescence subsp. clarkei symbiotic bacteria. CONCLUSIONS The discovery of H. casmirica n. sp. provides novel insights into the diversity and evolution of Heterorhabditis nematodes and their symbiotic bacteria. This new species adds to the catalog of entomopathogenic nematodes in India.
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Affiliation(s)
- Aashaq Hussain Bhat
- Department of Biosciences, 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, 2000, Switzerland.
| | - Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Neuchâtel, 2000, Switzerland
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus 'Las Lagunillas', Jaén, 23071, Spain
| | - Alba N Ruiz-Cuenca
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus 'Las Lagunillas', Jaén, 23071, Spain
| | - Tarique Hassan Askary
- Division of Entomology, Faculty of Agriculture, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Wadura Campus, Sopore, 193201, Jammu and Kashmir, India
| | - Fuad Ameen
- Department of Botany and Microbiology, College of Science, King Saud University, 11451, Riyadh, Saudi Arabia
| | - Wasim Muzamil Dass
- Department of Zoology, University of Kashmir, Srinagar, 190006, Jammu and Kashmir, India
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Janardhan HN, Askary TH, Bhat AH, Rana A, Ahad I, Al-Qahtani WH. Morphological and molecular profiling of an entomopathogenic nematode Steinernema feltiae: Unlocking its biocontrol potential against vegetable insect pests. Zootaxa 2023; 5351:202-220. [PMID: 38221492 DOI: 10.11646/zootaxa.5351.2.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Indexed: 01/16/2024]
Abstract
A population of entomopathogenic nematodes, belonging to the Feltiae-clade and labelled J13, was discovered in the agricultural soils of the hilly regions of the Union territory of Jammu and Kashmir, India. Based on morphological, morphometric, and molecular analyses, the nematodes were identified as Steinernema feltiae. The J13 nematode isolate was tested in a laboratory assay for its pathogenicity against six major pests of vegetable crops: Pieris brassicae, Plutella xylostella, Helicoverpa armigera, Agrotis iplison, Trichoplusia ni, and Exelastis atomosa. The morphology of the isolated nematode closely matched the original description, except for the adult females, which had prominent epiptygmata instead of the weakly developed, double-flapped epiptygmata described in the original report. Analysis of the internal transcribed spacer and large subunit rRNA data from the J13 nematodes showed 100% similarity to sequences of the type population, indicating that they are conspecific. The virulence assays revealed that the nematode caused 100% mortality in the tested insect pests within 4872 hours, even at the lowest concentration of 50 infective juveniles per insect. The calculated median lethal concentration varied among the pests, with the lowest number of infective juveniles needed to achieve 50% larval killing being 117 for P. xylostella, 181.74 for P. brassicae, 226.35 for H. armigera, and 202.07 for T. ni at 24 hours post-inoculation. These findings suggest that S. feltiae isolated during the present investigation, may be a viable option for the biocontrol of these insect pests in Kashmir valley, India.
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Affiliation(s)
- Hiriyannanahalli Narayanaswamy Janardhan
- Division of Entomology; Faculty of Agriculture; Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir; Wadura; Sopore -193201; Jammu and Kashmir; India.
| | - Tarique Hassan Askary
- Division of Entomology; Faculty of Agriculture; Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir; Wadura; Sopore -193201; Jammu and Kashmir; India.
| | - Aashaq Hussain Bhat
- Department of Bioscience; University Center for Research & Development (UCRD); Chandigarh University; Mohali 140413; Punjab; India; Experiemtal Biology Research Group; Institute of Biology; Faculty of Science; University of Neuchatel; Rue Emile-Argland 2000; Neuchatel; Switzerland.
| | - Aasha Rana
- Department of Zoology; Faculty of Basic and Applied Sciences; Madhav University; Pindwara (Sirohi); Rajasthan; 307026; India.
| | - Ishtiyaq Ahad
- Division of Entomology; Faculty of Agriculture; Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir; Wadura; Sopore -193201; Jammu and Kashmir; India.
| | - Wahidah H Al-Qahtani
- Department of Food Sciences and Nutrition; College of Food & Agriculture Sciences; King Saud University; Riyadh 11451; Saudi Arabia.
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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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Loulou A, Mastore M, Caramella S, Bhat AH, Brivio MF, Machado RAR, Kallel S. Entomopathogenic potential of bacteria associated with soil-borne nematodes and insect immune responses to their infection. PLoS One 2023; 18:e0280675. [PMID: 36689436 PMCID: PMC10045567 DOI: 10.1371/journal.pone.0280675] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/06/2023] [Indexed: 01/24/2023] Open
Abstract
Soil-borne nematodes establish close associations with several bacterial species. Whether they confer benefits to their hosts has been investigated in only a few nematode-bacteria systems. Their ecological function, therefore, remains poorly understood. In this study, we isolated several bacterial species from rhabditid nematodes, molecularly identified them, evaluated their entomopathogenic potential on Galleria mellonella larvae, and measured immune responses of G. mellonella larvae to their infection. Bacteria were isolated from Acrobeloides sp., A. bodenheimeri, Heterorhabditis bacteriophora, Oscheius tipulae, and Pristionchus maupasi nematodes. They were identified as Acinetobacter sp., Alcaligenes sp., Bacillus cereus, Enterobacter sp., Kaistia sp., Lysinibacillus fusiformis, Morganella morganii subsp. morganii, Klebsiella quasipneumoniae subsp. quasipneumoniae, and Pseudomonas aeruginosa. All bacterial strains were found to be highly entomopathogenic as they killed at least 53.33% G. mellonella larvae within 72h post-infection, at a dose of 106 CFU/larvae. Among them, Lysinibacillus fusiformis, Enterobacter sp., Acinetobacter sp., and K. quasipneumoniae subsp. quasipneumoniae were the most entomopathogenic bacteria. Insects strongly responded to bacterial infection. However, their responses were apparently little effective to counteract bacterial infection. Our study, therefore, shows that bacteria associated with soil-borne nematodes have entomopathogenic capacities. From an applied perspective, our study motivates more research to determine the potential of these bacterial strains as biocontrol agents in environmentally friendly and sustainable agriculture.
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Affiliation(s)
- Ameni Loulou
- Department of Plant Health and Environment, Laboratory of Bio-Aggressor and Integrated Protection in Agriculture, National Agronomic Institute of Tunisia, University of Carthage, Tunis, Tunisia
| | - Maristella Mastore
- Department of Theoretical and Applied Sciences, Laboratory of Comparative Immunology and Parasitology, University of Insubria, Varese, Italy
| | - Sara Caramella
- Department of Theoretical and Applied Sciences, Laboratory of Comparative Immunology and Parasitology, University of Insubria, Varese, Italy
| | - Aashaq Hussain Bhat
- Faculty of Sciences, Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Maurizio Francesco Brivio
- Department of Theoretical and Applied Sciences, Laboratory of Comparative Immunology and Parasitology, University of Insubria, Varese, Italy
| | - Ricardo A. R. Machado
- Faculty of Sciences, Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Sadreddine Kallel
- Department of Plant Health and Environment, Laboratory of Bio-Aggressor and Integrated Protection in Agriculture, National Agronomic Institute of Tunisia, University of Carthage, Tunis, Tunisia
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Yadav K, Bhat AH, Abolafia J, Machado RA, Wani SM, Chaubey AK. Redescription and molecular characterisation of Panagrolaimus labiatus (Kreis, 1929) Andrássy, 1960 (Rhabditida, Panagrolaimidae) from India and proposal of P. burdwanensis Chaturvedi & Khera, 1979 as a junior synonym of P. labiatus. NEMATOLOGY 2022. [DOI: 10.1163/15685411-bja10211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Summary
Two populations of bacterial-feeding nematodes belonging to the genus Panagrolaimus were recovered from infected slugs collected from gardens, agricultural areas and nurseries of the Baghpat district (India). Initial morphological characterisation of these populations show that they resemble Panagrolaimus labiatus from China and Bulgaria, P. burdwanensis from India, and P. cf. labiatus from Iran. To clarify taxonomical affiliations, we morphologically compared these two new populations to those recovered from China, Bulgaria, India and Iran. In addition, we sequenced several taxonomically relevant genes and used them to reconstruct phylogenetic relationships. Our results show that the two Indian populations do not significantly differ morphologically from the specimens used to describe the species P. labiatus, and also do not differ among them. We only observed small variations in the size of males and females. In addition, morphologically, the nematodes used to describe P. burdwanensis are very similar to the nematodes used to describe P. labiatus and to the two populations described in this study. Therefore, we propose P. burdwanensis as a junior synonym of P. labiatus and that the two populations recovered from India belong to the P. labiatus species. Phylogenetic analyses using the nucleotide sequences of the internal transcribed spacer (ITS), 18S and 28S rRNA gene sequences support our morphological conclusions. Our study therefore provides a detailed morphological description and molecular marker 18S and 28S gene sequences that can support future taxonomical studies of this species and highlights the importance of using both molecular and morphological data for the proper description of soil microfauna.
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Affiliation(s)
- Kajol Yadav
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, 250004, Uttar Pradesh, India
| | - Aashaq Hussain Bhat
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Campus ‘Las Lagunillas’ s/n, Edificio B3, 23071 Jaén, Spain
| | - Ricardo A.R. Machado
- Experimental Biology Research Group, Institute of Biology, Faculty of Sciences, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Shaheen Majeed Wani
- Nematode Biodiversity and Genomics Research Laboratory, Baba Ghulam Shah Badshah University Rajouri, 185234, Jammu and Kashmir, India
| | - Ashok Kumar Chaubey
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, 250004, Uttar Pradesh, India
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Loulou A, M’saad Guerfali M, Muller A, Bhat AH, Abolafia J, Machado RAR, Kallel S. Potential of Oscheius tipulae nematodes as biological control agents against Ceratitis capitata. PLoS One 2022; 17:e0269106. [PMID: 35671263 PMCID: PMC9200223 DOI: 10.1371/journal.pone.0269106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/13/2022] [Indexed: 11/18/2022] Open
Abstract
A survey to collect soil nematodes with potential to control Ceratitis
capitata flies was carried out in different locations in Tunisia.
Several nematode isolates were recovered, laboratory colonies were established,
and their taxonomic identities were determined based on molecular methods. Among
all the recovered nematode isolates, two of them, Oscheius
tipulae TC2 and OC2, were evaluated for their capacity to control
C. capitata flies and for their ability to
kill and reproduce on Galleria mellonella larvae. Our results
show a great potential of these two isolates as biocontrol agents as they kill
C. capitata eggs and pupae and interfere
with the metamorphosis of C. capitata larvae.
More specifically, TC2 and OC2 nematodes killed 39 and 31% of
C. capitata eggs, respectively, impaired the
metamorphosis of up to 77% and up to 67% of C.
capitata larvae, respectively, and killed up to 66% and up
to 58% of C. capitata pupae, respectively. The
efficacy of TC2 and OC2 nematodes was particularly high on C.
capitata pupae, and significant insect mortalities were
observed even at concentrations of 1 and 5 nematodes/pupae, respectively. We
also found that TC2 and OC2 nematodes efficiently kill and reproduce in
G. mellonella larvae, suggesting that
these insects could be used for mass-multiplication of these nematodes. These
results reveal the potential of O. tipulae to
complement integrated pest management programs against C.
capitata flies.
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Affiliation(s)
- Ameni Loulou
- Laboratory of Bio-aggressor and Integrated Protection in Agriculture,
Department of Plant health and Environment, National Agronomic Institute of
Tunisia, University of Carthage, Tunis, Tunisia
| | - Meriem M’saad Guerfali
- Laboratory of Biotechnology and Nuclear Technologies, National Center of
Nuclear Sciences and Technologies, Technopole Sidi Thabet, Ariana,
Tunisia
| | - Arthur Muller
- Faculty of Sciences, Experimental Biology Research Group, Institute of
Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Aashaq Hussain Bhat
- Faculty of Sciences, Experimental Biology Research Group, Institute of
Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Department of Zoology, Government Degree College, Kathua, Jammu, Jammu
and Kashmir, India
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad
de Jaén, Jaén, Spain
| | - Ricardo A. R. Machado
- Faculty of Sciences, Experimental Biology Research Group, Institute of
Biology, University of Neuchâtel, Neuchâtel, Switzerland
- * E-mail: (RARM); (SK)
| | - Sadreddine Kallel
- Laboratory of Bio-aggressor and Integrated Protection in Agriculture,
Department of Plant health and Environment, National Agronomic Institute of
Tunisia, University of Carthage, Tunis, Tunisia
- * E-mail: (RARM); (SK)
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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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Bacterial communities associated with Zeldia punctata, a bacterivorous soil-borne nematode. Int Microbiol 2021; 25:207-216. [PMID: 34553287 DOI: 10.1007/s10123-021-00207-8] [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: 06/15/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 10/20/2022]
Abstract
Soil inhabiting organisms are important determinants of agroecosystem productivity. Understanding the composition, the abundance, and the type of interactions established by soil microorganisms is therefore crucial to design strategies to improve agricultural practices and agroecosystem management. In this study, we collected Zeldia punctata nematodes in maize fields in South Africa and profiled their associated bacterial communities using next-generation sequencing. We observed that Z. punctata nematodes establish associations with ecologically diverse bacterial species. The most abundant species observed are Pseudomonas syringae, a phytopathogenic bacterial complex; Lactobacillus paraplantarum, a broadly distributed bacterial species that is present in soils, water bodies, and animal intestinal tracts and has certain probiotic and antimicrobial properties; and Melissococcus plutonius, a serious pathogenic bacterial species that causes brood disease in honeybees. Our study contributes to a better understanding of the soil bacterial communities associated with nematodes in maize agricultural soils in South Africa and unravels the presence of diverse detrimental and beneficial nematode-associated bacteria.
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Redescription and synonymization of Oscheius citri Tabassum, Shahina, Nasira and Erum, 2016 (Rhabditida, Rhabditidae) from India and its taxonomical consequences. J Helminthol 2021; 95:e24. [PMID: 33880988 DOI: 10.1017/s0022149x21000134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A population of a nematode species belonging to the genus Oscheius was isolated in western Uttar Pradesh, India. Morphological and morphometrical studies on this species showed its high similarity with six species described previously from Pakistan (Oscheius citri, O. cobbi, O. cynodonti, O. esculentus, O. punctatus and O. sacchari). The molecular analysis of the ITS1-5.8S-ITS2 rDNA sequences of the Indian population and the six species described from Pakistan showed that all the sequences are almost identical. Thus, based on morphological and molecular characteristics, all of the six above-mentioned Pakistani species and Indian strain do not differ from each other, hence can be considered synonyms. The correct name for this taxon is the first described species O. citri. Additionally, the phylogenetic analysis of the 18S rDNA and the 28S rDNA sequences showed that Oscheius citri is sister to the clade formed by O. chongmingensis and O. rugaoensis from China. The high similarity of morphological and morphometric characteristics of O. citri and other species, O. maqbooli, O. nadarajani, O. niazii, O. shamimi and O. siddiqii, suggest their conspecificity; however, lack of molecular data for these species does not allow this hypothesis to be tested.
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Bhat AH, Srivastava S, Rana A, Chaubey AK, Machado RAR, Abolafia J. Morphological, morphometrical, and molecular characterization of Metarhabditis amsactae (Ali, Pervez, Andrabi, Sharma and Verma, 2011) Sudhaus, 2011 (Rhabditida, Rhabditidae) from India and proposal of Metarhabditis longicaudata as a junior synonym of M. amsactae. J Nematol 2020; 52:e2020-116. [PMID: 33829202 PMCID: PMC8015365 DOI: 10.21307/jofnem-2020-116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Indexed: 01/08/2023] Open
Abstract
A new population of Metarhabditis amsactae from India is morphologically, morphometrically, and molecularly characterized. This material is characterized by having 0.65 to 1.14 mm length, lips rounded, and grouped in pairs, stoma with metastegostoma bearing setose denticles, pharynx with metacorpus slightly swollen and fusiform, nerve ring, and excretory pore located at isthmus level, female reproductive system didelphic-amphidelphic with vulva equatorial, female tail conical-elongate with acute tip, male tail conical with large and robust posterior filiform part, spicules free with hooked manubrium slightly bent ventrad, gubernaculum with narrow corpus, bursa open leptoderan with eight genital papillae and phasmids posterior to the GP8. Molecular studies based on 18S and 28S rDNA genes are provided for the first time for the species. In addition, integrated morphological, morphometrical, and molecular characters are compared with other previous records of the species. According to our analysis, Metarhabditis longicaudata and other material described as different species are proposed as new junior synonyms of M. amsactae.
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Affiliation(s)
- Aashaq Hussain Bhat
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, India
- Government Degree College, Billawar, 184204, Kathua, Jammu and Kashmir, India
| | - Shreyansh Srivastava
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, India
| | - Aasha Rana
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, India
| | - Ashok Kumar Chaubey
- Nematology Laboratory, Department of Zoology, Chaudhary Charan Singh University, Meerut, India
| | - Ricardo A. R. Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Joaquín Abolafia
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Jaén, Spain
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