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Mathur C, Phani V, Kushwah J, Somvanshi VS, Dutta TK. TcaB, an insecticidal protein from Photorhabdus akhurstii causes cytotoxicity in the greater wax moth, Galleria mellonella. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2019; 157:219-229. [PMID: 31153472 DOI: 10.1016/j.pestbp.2019.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/22/2019] [Accepted: 03/31/2019] [Indexed: 06/09/2023]
Abstract
Photorhabdus akhurstii can produce a variety of proteins that aid this bacterium and its mutualistic nematode vector, Heterorhabditis indica to kill the insect host. Herein, we characterized (by heterologously expressing in E. coli) an open reading frame (1713 bp) of the toxin complex protein, TcaB from P. akhurstii strains IARI-SGHR2 and IARI-SGMS1 and assessed its toxic effect on G. mellonella larvae. The intra-hemocoel injection of purified TcaB (molecular weight-63 kDa) caused fourth instar larval bodies to blacken and die with LD50 values of 67.25 (IARI-SGHR2) and 52.08 (IARI-SGMS1) ng per larva at 12 h. Additionally, oral administration of the toxin caused larval mortality with LD50 values of 709.55 (IARI-SGHR2) and 598.44 (IARI-SGMS1) ng per g diet per larva at 7 days post feeding. Injection of purified TcaB caused loss of viability of fourth instar G. mellonella hemocytes at 6 h post incubation; cells displayed morphological changes typical of apoptosis, including cell shrinkage, membrane blebbing, nuclear condensation and disintegration. Injection of TcaB also elevated the phenoloxidase activity in insect hemolymph which triggers an extensive immune response that potentially leads to larval death. Similar to other bacterial toxins TcaB possesses potent biological activity which may enable it to be used as an efficient agent for pest management.
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Affiliation(s)
- Chetna Mathur
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Victor Phani
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Jyoti Kushwah
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Vishal S Somvanshi
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Tushar K Dutta
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
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Blanco-Pérez R, Bueno-Pallero FÁ, Vicente-Díez I, Marco-Mancebón VS, Pérez-Moreno I, Campos-Herrera R. Scavenging behavior and interspecific competition decrease offspring fitness of the entomopathogenic nematode Steinernema feltiae. J Invertebr Pathol 2019; 164:5-15. [PMID: 30974088 DOI: 10.1016/j.jip.2019.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 04/05/2019] [Accepted: 04/07/2019] [Indexed: 12/17/2022]
Abstract
Entomopathogenic nematodes (EPNs) are well-studied biocontrol agents of soil-dwelling arthropod pests. The insecticidal efficiency of EPNs is modulated by food web dynamics. EPNs can reproduce in freeze-killed insect larvae, even in competition with free-living bacterivorous nematodes (FLBNs) in the genus Oscheius. The objective of this study was to assess the efficiency of EPNs as scavengers when competing with free-living saprophagous nematodes and fungi, and to determine the possible impact on subsequent EPN offspring fitness. Live and freeze-killed larvae of Galleria mellonella were used to evaluate the reproduction rate and progeny fitness of two EPN species, Heterorhabditis bacteriophora and Steinernema feltiae, applied individually or combined with the FLBN species Oscheius onirici or Pristionchus maupasi, or Aspergillus flavus, an opportunistic saprophytic fungus. We hypothesized that (1) EPN scavenging behaviors previously observed (for H. megidis and S. kraussei) apply to other EPN species, (2) infective juveniles (IJs) emerging from freeze-killed larvae will display reduced pathogenicity and reproduction, and (3) fitness reduction will be amplified by exposure to other organisms competing for the resources. The reproduction rate of S. feltiae was lower in freeze-killed larvae than in larvae infected and killed by the nematode, whereas H. bacteriophora failed to reproduce as a scavenger. The S. feltiae F1 IJs that emerged from freeze-killed larvae exhibited lower pathogenicity rates than IJs resulting from entomopathogenic activity, and also lower reproductive rates if they experienced high FLBN competitive pressure during development. This study illustrates that scavenging is a suboptimal alternative pathway for EPNs, especially in the face of scavenger competition, even though it provides a means for some EPN species to complete their life-cycle.
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Affiliation(s)
- Rubén Blanco-Pérez
- MeditBio, Centre for Mediterranean Bioresources and Food, Universidade do Algarve, Campus de Gambelas, 8005 Faro, Portugal; Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja), Finca La Grajera, 26007 Logroño, Spain
| | - Francisco Ángel Bueno-Pallero
- MeditBio, Centre for Mediterranean Bioresources and Food, Universidade do Algarve, Campus de Gambelas, 8005 Faro, Portugal
| | - Ignacio Vicente-Díez
- Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja), Finca La Grajera, 26007 Logroño, Spain
| | | | - Ignacio Pérez-Moreno
- Departamento de Agricultura y Alimentación, Universidad de La Rioja, 26006 Logroño, Spain
| | - Raquel Campos-Herrera
- MeditBio, Centre for Mediterranean Bioresources and Food, Universidade do Algarve, Campus de Gambelas, 8005 Faro, Portugal; Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja), Finca La Grajera, 26007 Logroño, Spain.
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Machado RAR, Bruno P, Arce CCM, Liechti N, Köhler A, Bernal J, Bruggmann R, Turlings TCJ. Photorhabdus khanii subsp. guanajuatensis subsp. nov., isolated from Heterorhabditis atacamensis, and Photorhabdus luminescens subsp. mexicana subsp. nov., isolated from Heterorhabditis mexicana entomopathogenic nematodes. Int J Syst Evol Microbiol 2019; 69:652-661. [PMID: 30688647 DOI: 10.1099/ijsem.0.003154] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two Gram-negative, rod-shaped, non-spore-forming bacteria, MEX20-17T and MEX47-22T, were isolated from the digestive system of Heterorhabditis atacamensis and Heterorhabditis mexicana entomopathogenic nematodes, respectively. Their 16S rRNA gene sequences suggest that strains MEX20-17T and MEX47-22T belong to the γ-Proteobacteria and to the genus Photorhabdus. Deeper analyses using housekeeping-gene-based and whole-genome-based phylogenetic reconstruction suggest that MEX20-17T is closely related to Photorhabdus khanii and that MEX47-22T is closely related to Photorhabdus luminescens. Sequence similarity scores confirm these observations: MEX20-17T and P. khanii DSM 3369T share 98.9 % nucleotide sequence identity (NSI) of concatenated housekeeping genes, 70.4 % in silico DNA-DNA hybridization (isDDH) and 97 % orthologous average nucleotide identity (orthoANI); and MEX47-22T and P. luminescens ATCC 29999T share 98.9 % NSI, 70.6 % isDDH and 97 % orthoANI. Physiological characterization indicates that both strains differ from all validly described Photorhabdus species and from their more closely related taxa. We therefore propose to classify MEX20-17T and MEXT47-22T as new subspecies within P. khanii and P. luminescens, respectively. Hence, the following names are proposed for these strains: Photorhabdus khanii subsp. guanajuatensis subsp. nov. with the type strain MEX20-17T (=LMG 30372T=CCOS 1191T) and Photorhabdus luminescenssubsp. mexicana subsp. nov. with the type strain MEX47-22T (=LMG 30528T=CCOS 1199T). These propositions automatically create Photorhabdus khanii subsp. khanii subsp. nov. with DSM 3369T as the type strain (currently classified as P. khanii), and Photorhabdus luminescenssubsp. luminescenssubsp. nov. with ATCC 29999T as the type strain (currently classified as P. luminescens).
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Affiliation(s)
| | - Pamela Bruno
- 2Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Carla C M Arce
- 2Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Nicole Liechti
- 3Interfaculty Bioinformatics Unit, University of Bern, Bern, Switzerland
| | - Angela Köhler
- 2Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland
- 4Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie, Jena, Germany
| | - Julio Bernal
- 5Department of Entomology, Texas A&M University, College Station, Texas, USA
| | - Rémy Bruggmann
- 2Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ted C J Turlings
- 2Laboratory of Fundamental and Applied Research in Chemical Ecology, University of Neuchâtel, Neuchâtel, Switzerland
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Draft Genome Sequences for Five Photorhabdus Bacterial Symbionts of Entomopathogenic Heterorhabditis Nematodes Isolated from India. Microbiol Resour Announc 2019; 8:MRA01404-18. [PMID: 30701235 PMCID: PMC6346184 DOI: 10.1128/mra.01404-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/17/2018] [Indexed: 11/20/2022] Open
Abstract
Photorhabdus bacteria exhibit contrasting lifestyles; they are virulent insect pathogens but symbionts of the entomopathogenic Heterorhabditis nematodes. Photorhabdus genomes encode several secondary metabolites and insecticidal protein toxins. Photorhabdus bacteria exhibit contrasting lifestyles; they are virulent insect pathogens but symbionts of the entomopathogenic Heterorhabditis nematodes. Photorhabdus genomes encode several secondary metabolites and insecticidal protein toxins. Here, we present the draft genome sequences for five Photorhabdus strains isolated from Heterorhabditis nematodes collected from various geographical regions of India.
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Proposed nomenclature or classification changes for bacteria of medical importance: Taxonomic Update 4. Diagn Microbiol Infect Dis 2018; 94:205-208. [PMID: 30683468 DOI: 10.1016/j.diagmicrobio.2018.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 11/22/2022]
Abstract
A key aspect of medical, public health, and diagnostic microbiology laboratories is the accurate identification and rapid reporting and communication to medical staff regarding patients with infectious agents of clinical importance. Microbial taxonomy continues to change at a very rapid rate in the era of molecular diagnostics including whole genome sequencing. This update focuses on taxonomic changes and proposals that may be of medical importance for years 2017 and 2018.
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Zamora-Lagos MA, Eckstein S, Langer A, Gazanis A, Pfeiffer F, Habermann B, Heermann R. Phenotypic and genomic comparison of Photorhabdus luminescens subsp. laumondii TT01 and a widely used rifampicin-resistant Photorhabdus luminescens laboratory strain. BMC Genomics 2018; 19:854. [PMID: 30497380 PMCID: PMC6267812 DOI: 10.1186/s12864-018-5121-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 09/26/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Photorhabdus luminescens is an enteric bacterium, which lives in mutualistic association with soil nematodes and is highly pathogenic for a broad spectrum of insects. A complete genome sequence for the type strain P. luminescens subsp. laumondii TT01, which was originally isolated in Trinidad and Tobago, has been described earlier. Subsequently, a rifampicin resistant P. luminescens strain has been generated with superior possibilities for experimental characterization. This strain, which is widely used in research, was described as a spontaneous rifampicin resistant mutant of TT01 and is known as TT01-RifR. RESULTS Unexpectedly, upon phenotypic comparison between the rifampicin resistant strain and its presumed parent TT01, major differences were found with respect to bioluminescence, pigmentation, biofilm formation, haemolysis as well as growth. Therefore, we renamed the strain TT01-RifR to DJC. To unravel the genomic basis of the observed differences, we generated a complete genome sequence for strain DJC using the PacBio long read technology. As strain DJC was supposed to be a spontaneous mutant, only few sequence differences were expected. In order to distinguish these from potential sequencing errors in the published TT01 genome, we re-sequenced a derivative of strain TT01 in parallel, also using the PacBio technology. The two TT01 genomes differed at only 30 positions. In contrast, the genome of strain DJC varied extensively from TT01, showing 13,000 point mutations, 330 frameshifts, and 220 strain-specific regions with a total length of more than 300 kb in each of the compared genomes. CONCLUSIONS According to the major phenotypic and genotypic differences, the rifampicin resistant P. luminescens strain, now named strain DJC, has to be considered as an independent isolate rather than a derivative of strain TT01. Strains TT01 and DJC both belong to P. luminescens subsp. laumondii.
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Affiliation(s)
- Maria-Antonia Zamora-Lagos
- Computational Biology Group, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Simone Eckstein
- Biozentrum, Bereich Mikrobiologie, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152, Martinsried, Germany
| | - Angela Langer
- Biozentrum, Bereich Mikrobiologie, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152, Martinsried, Germany
| | - Athanasios Gazanis
- Biozentrum, Bereich Mikrobiologie, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152, Martinsried, Germany
| | - Friedhelm Pfeiffer
- Computational Biology Group, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Bianca Habermann
- Computational Biology Group, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany. .,CNRS UMR 7288, Computational Biology Group, Developmental Biology Institute of Marseille (IBDM), Aix Marseille Université, 13009, Marseille, France.
| | - Ralf Heermann
- Biozentrum, Bereich Mikrobiologie, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152, Martinsried, Germany.
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