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Hyde J, Brackney DE, Steven B. Three species of axenic mosquito larvae recruit a shared core of bacteria in a common garden experiment. Appl Environ Microbiol 2023; 89:e0077823. [PMID: 37681948 PMCID: PMC10537770 DOI: 10.1128/aem.00778-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/05/2023] [Indexed: 09/09/2023] Open
Abstract
In this study, we describe the generation of two new species of axenic mosquito, Aedes albopictus and Aedes triseriatus. Along with Aedes aegypti, axenic larvae of these three species were exposed to an environmental water source to document the assembly of the microbiome in a common garden experiment. Additionally, the larvae were reared either individually or combinatorially with the other species to characterize the effects of co-rearing on the composition of the microbiome. We found that the microbiome of the larvae was composed of a relatively low-diversity collection of bacteria from the colonizing water. The abundance of bacteria in the water was a poor predictor of their abundance in the larvae, suggesting the larval microbiome is made up of a subset of relatively rare aquatic bacteria. We found 11 bacterial 16S rRNA gene amplicon sequence variants (ASVs) that were conserved among ≥90% of the mosquitoes sampled, including 2 found in 100% of the larvae, pointing to a conserved core of bacteria capable of colonizing all three species of mosquito. Yet, the abundance of these ASVs varied widely between larvae, suggesting individuals harbored largely unique microbiome structures, even if they overlapped in membership. Finally, larvae reared in a tripartite mix of the host-species consistently showed a convergence in the structure of their microbiome, indicating that multi-species interactions between hosts potentially lead to shifts in the composition of their respective microbiomes. IMPORTANCE This study is the first report of the axenic (free of external microbes) rearing of two species of mosquito, Aedes albopictus and Aedes triseriatus. Our previous report of axenic Aedes aegypti brings the number of axenic species to three. We designed a method to perform a common garden experiment to characterize the bacteria the three species of axenic larvae assemble from their surroundings. Furthermore, species could be reared in isolation or in multi-species combinations to assess how host-species interactions influence the composition of the microbiome. We found all three species recruited a common core of bacteria from their rearing water, with a large contingent of rare and sporadically detected bacteria. Finally, we also show that co-rearing of mosquito larvae leads to a coalescence in the composition of their microbiome, indicating that host-species interactions potentially influence the composition of the microbiome.
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Affiliation(s)
- Josephine Hyde
- Department of Environmental Science and Forestry, Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Doug E. Brackney
- Department of Entomology, Center for Vector Biology and Zoonotic Diseases, Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
| | - Blaire Steven
- Department of Environmental Science and Forestry, Connecticut Agricultural Experiment Station, New Haven, Connecticut, USA
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2
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Kumar A, Kumar H, Manonmani AM, Prabakaran G, Vijayakumar B, Mathivanan A, Geetha I, Jambulingam P. Field evaluation of biosurfactants, surfactin and di-rhamnolipid produced by Bacillus subtilis subsp. subtilis (VCRC B471) and Pseudomonas fluorescens (VCRC B426) against immature stages of the urban malaria vector Anopheles stephensi. J Vector Borne Dis 2022; 59:246-252. [PMID: 36511041 DOI: 10.4103/0972-9062.342401] [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: 12/15/2022] Open
Abstract
BACKGROUND & OBJECTIVES Bacillus subtilis subsp. subtilis (VCRC B471) and Pseudomonas fluorescens (B426) produce mosquitocidal biosurfactant, surfactin and di-rhamnolipid. The objective of the study was to carry out a small-scale field evaluation of the two biosurfactants to determine the efficacy, application dosage, residual activity and frequency of application against Anopheles stephensi immatures in selected sites in Goa, India. METHODS Surfactin (VCRC B471) and di-rhamnolipid (VCRC B426) were formulated as aqueous suspensions (5% AS), and were applied at the dosages of 34, 51 and 68 mL/m2 and 27, 41 and 54 mL/m2 respectively. Two experiments were carried out with the two formulations. RESULTS Surfactin (VCRC B471) formulation was effective at all the dosages and there was sustained reduction (>80%) in immature density in the treated sites up to 18 days in experiment 1 and up to 15 days in experiment 2. No pupae were found in the treated sites throughout the study. Di-rhamnolipid (VCRC B426) formulation was also found to reduce the immature density in the treated sites up to 14 days in experiment 1 and up to 15 days in experiment 2. INTERPRETATION & CONCLUSION For VCRC B471, the optimum application dosage determined was 51 mL/m2 and for VCRC B426, 27mL/m2. The formulations are to be applied fortnightly for effective control of Anopheles. The application dosage determined in the present study can be used for large scale field evaluation to assess their suitability for use in public health programmes for the control of Anopheles mosquitoes vectoring malaria.
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Affiliation(s)
- Ashwani Kumar
- ICMR-National Institute of Malaria Research, Field Unit, DHS, Campal, Panaji, Goa; ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
| | - Hemanth Kumar
- ICMR-National Institute of Malaria Research, Field Unit, DHS, Campal, Panaji, Goa, India
| | - A M Manonmani
- ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
| | - G Prabakaran
- ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
| | - B Vijayakumar
- ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
| | - A Mathivanan
- ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
| | - I Geetha
- ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
| | - P Jambulingam
- ICMR-Vector Control Research Centre, Medical Complex, Indira Nagar, Puducherry, India
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Li E, Ryo M, Kowalchuk GA, Bakker PAHM, Jousset A. Rapid evolution of trait correlation networks during bacterial adaptation to the rhizosphere. Evolution 2021; 75:1218-1229. [PMID: 33634862 PMCID: PMC8252368 DOI: 10.1111/evo.14202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 02/04/2021] [Accepted: 02/12/2021] [Indexed: 12/22/2022]
Abstract
There is a growing awareness that traits do not evolve individually but rather are organized as modular networks of covarying traits. Although the importance of multi-trait correlation has been linked to the ability to evolve in response to new environmental conditions, the evolvability of the network itself has to date rarely been assessed experimentally. By following the evolutionary dynamics of a model bacterium adapting to plant roots, we demonstrate that the whole structure of the trait correlation network is highly dynamic. We experimentally evolved Pseudomonas protegens, a common rhizosphere dweller, on the roots of Arabidopsis thaliana. We collected bacteria at regular intervals and determined a range of traits linked to growth, stress resistance, and biotic interactions. We observed a rapid disintegration of the original trait correlation network. Ancestral populations showed a modular network, with the traits linked to resource use and stress resistance forming two largely independent modules. This network rapidly was restructured during adaptation, with a loss of the stress resistance module and the appearance of new modules out of previously disconnected traits. These results show that evolutionary dynamics can involve a deep restructuring of phenotypic trait organization, pointing to the emergence of novel life history strategies not represented in the ancestral phenotype.
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Affiliation(s)
- Erqin Li
- Department of Biology, Plant‐Microbe InteractionsUtrecht UniversityUtrechtCH3584The Netherlands
- Institut für BiologieFreie Universität BerlinBerlinD‐14195Germany
- Berlin‐Brandenburg Institute of Advanced Biodiversity ResearchBerlinD‐14195Germany
| | - Masahiro Ryo
- Institut für BiologieFreie Universität BerlinBerlinD‐14195Germany
- Berlin‐Brandenburg Institute of Advanced Biodiversity ResearchBerlinD‐14195Germany
- Leibniz Centre for Agricultural Landscape Research (ZALF)Müncheberg15374Germany
- Institute of Environmental SciencesBrandenburg University of TechnologyCottbus03046Germany
| | - George A. Kowalchuk
- Department of Biology, Ecology, and BiodiversityUtrecht UniversityUtrechtCH3584The Netherlands
| | - Peter A. H. M. Bakker
- Department of Biology, Plant‐Microbe InteractionsUtrecht UniversityUtrechtCH3584The Netherlands
| | - Alexandre Jousset
- Department of Biology, Ecology, and BiodiversityUtrecht UniversityUtrechtCH3584The Netherlands
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4
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Suganthi M, Arvinth S, Senthilkumar P. Comparative bioefficacy of Bacillus and Pseudomonas chitinase against Helopeltis theivora in tea ( Camellia sinensis (L.) O.Kuntze. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:2053-2060. [PMID: 33088049 PMCID: PMC7548272 DOI: 10.1007/s12298-020-00875-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/14/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Tea (Camellia sinensis (L.) O.Kuntze) is an industry-oriented economical crop in India. Among the sap sucking pests, tea mosquito bug (Helopeltis theivora) is one of the most serious pests causing heavy crop loss in tea plantation. Continuous use of chemical pesticides causes environmental pollution and health hazards besides developing pesticide residues in tea powder. The control of pests by bacterial metabolite is an alternative that may contribute to reduce or eliminate the chemical pesticide use. The use of chitinase as a biological control is an emerging field of research. In the present study, Chitinase (~ 25 kDa) was purified from Bacillus cereus C-13 strain using gel-filtration chromatography and further characterized for its optimum pH, temperature and substrate specificity. Bioefficacy of chitinase from B. cereus C-13 was compared with our previously reported Pseudomonas fluorescens MP-13 chitinase against H. theivora. Result concluded that, 100% and 78% mortality was observed by using P. fluorescens MP-13 chitinase and B. cereus C-13 chitinase, respectively. In future, bacterial chitinase can be utilized in eco-friendly pest management strategies.
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Affiliation(s)
- M. Suganthi
- Department of Plant Physiology and Biotechnology, UPASI Tea Research Institute, Valparai, Tamilnadu 642 127 India
- Department of Biotechnology, Vels Institute of Science, Technology and Advanced Studies (VISTAS), Pallavaram, Chennai, Tamilnadu 600 117 India
| | - S. Arvinth
- Department of Plant Physiology and Biotechnology, UPASI Tea Research Institute, Valparai, Tamilnadu 642 127 India
- Department of Botany, PSG College of Arts and Science, Coimbatore, Tamilnadu 641 004 India
| | - P. Senthilkumar
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Potheri, Kattankulathur, Chengalpattu District, Tamilnadu 603 203 India
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5
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Lopes LD, Davis EW, Pereira E Silva MDC, Weisberg AJ, Bresciani L, Chang JH, Loper JE, Andreote FD. Tropical soils are a reservoir for fluorescent Pseudomonas spp. biodiversity. Environ Microbiol 2017; 20:62-74. [PMID: 29027341 DOI: 10.1111/1462-2920.13957] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/07/2017] [Accepted: 10/08/2017] [Indexed: 11/30/2022]
Abstract
Fluorescent Pseudomonas spp. are widely studied for their beneficial activities to plants. To explore the genetic diversity of Pseudomonas spp. in tropical regions, we collected 76 isolates from a Brazilian soil. Genomes were sequenced and compared to known strains, mostly collected from temperate regions. Phylogenetic analyses classified the isolates in the P. fluorescens (57) and P. putida (19) groups. Among the isolates in the P. fluorescens group, most (37) were classified in the P. koreensis subgroup and two in the P. jessenii subgroup. The remaining 18 isolates fell into two phylogenetic subclades distinct from currently recognized P. fluorescens subgroups, and probably represent new subgroups. Consistent with their phylogenetic distance from described subgroups, the genome sequences of strains in these subclades are asyntenous to the genome sequences of members of their neighbour subgroups. The tropical isolates have several functional genes also present in known fluorescent Pseudomonas spp. strains. However, members of the new subclades share exclusive genes not detected in other subgroups, pointing to the potential for novel functions. Additionally, we identified 12 potential new species among the 76 isolates from the tropical soil. The unexplored diversity found in the tropical soil is possibly related to biogeographical patterns.
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Affiliation(s)
- Lucas Dantas Lopes
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil.,Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Edward W Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331, USA
| | - Michele de C Pereira E Silva
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Luana Bresciani
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331, USA
| | - Joyce E Loper
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331, USA
| | - Fernando D Andreote
- Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, SP, Brazil
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Valverde C. Who's the boss here? The post‐transcriptional global regulator
H
fq takes over control of secondary metabolite production in the nematode symbiont
P
hotorhabdus luminiscens. Environ Microbiol 2017; 19:21-24. [DOI: 10.1111/1462-2920.13635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Claudio Valverde
- Departamento de Ciencia y Tecnología, LBMIBSUniversidad Nacional de Quilmes – CONICETBernalB1876BXD Argentina
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7
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Suganthi M, Senthilkumar P, Arvinth S, Chandrashekara KN. Chitinase from Pseudomonas fluorescens and its insecticidal activity against Helopeltis theivora. J GEN APPL MICROBIOL 2017; 63:222-227. [DOI: 10.2323/jgam.2016.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- M. Suganthi
- Plant Physiology & Biotechnology Division, UPASI Tea Research Institute
| | | | - S. Arvinth
- Plant Physiology & Biotechnology Division, UPASI Tea Research Institute
- Department of Botany, PSG College of Arts and Science
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Prabakaran G, Hoti SL, Rao HSP, Vijjapu S. Di-rhamnolipid is a mosquito pupicidal metabolite from Pseudomonas fluorescens (VCRC B426). Acta Trop 2015; 148:24-31. [PMID: 25912083 DOI: 10.1016/j.actatropica.2015.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 02/24/2015] [Accepted: 03/03/2015] [Indexed: 11/30/2022]
Abstract
Pseudomonas fluorescens Migula (VCRC B426) produces a secondary metabolite, which was found to be active against pupae of vector mosquitoes namely Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti. The mosquito pupicidal metabolite from P. fluoescens was mass produced and separated by ethyl acetate extraction and purified further by silica gel column chromatography, FPLC, HPLC and TLC. The purified metabolite was characterized by NMR, FT-IR, LC-MS and MALDI-TOF. The FT-IR, (1)H and (13)C NMR results showed that it is a rhamnolipid (di-rhamnolipid). The matrix assisted laser desorption and ionization-time-of-flight spectrum of the sample showed predominant pupicidal component produced by P. fluorescens was the molecule mass of 673.40 Da. Owing to its high toxicity to mosquito pupae, especially Anopheles sp., and Aedes sp., the di-rhamnolipd has potential in the control of the vectors of dengue, chikungunya, yellow fever and malaria. This is the first report of mosquito pupicidal di-rhamnolipid from P. fluorescens.
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Affiliation(s)
- G Prabakaran
- Vector Control Research Centre (ICMR), IndiraNagar, Pondicherry 605006, India
| | - S L Hoti
- Regional Medical Research Centre (ICMR), Nehru Nagar, 590010 Belgaum, India.
| | | | - Satish Vijjapu
- Department of Chemistry, Pondicherry University, Pondicherry 605014, India
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Mary KA, Paily KP, Hoti SL, Balaraman K. Binding sites of mosquitocidal toxins of Pseudomonas fluorescens and Bacillus subtilis on pupae and larvae of Culex quinquefasciatus. J Immunoassay Immunochem 2014; 36:54-62. [PMID: 24624898 DOI: 10.1080/15321819.2014.895744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Two of the potential bacterial isolates, viz., Pseudomonas fluorescens (VCRC B-426) and Bacillus subtilis (VCRC B-471) whose toxins kill the mosquito pupae/larvae have been identified at our center. As the mode of action of these bacteria are not known, an attempt was made to find out the binding sites of the toxic proteins through immunological methods. Antibodies were raised in BALB/c mice and egg yolk system of chicken layers against the mosquitocidal proteins. The antibodies showed specific binding on to the cephalic and thoracic cuticle of the pupae as well as the paddles of the larvae, indicating the binding of the mosquitocidal proteins.
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Affiliation(s)
- K Athisaya Mary
- a Unit of Microbiology and Immunology, Vector Control Research Centre (Indian Council of Medical Research), Indira Nagar , Puducherry , India
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10
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Pseudomonas fluorescens strain CL145A – A biopesticide for the control of zebra and quagga mussels (Bivalvia: Dreissenidae). J Invertebr Pathol 2013; 113:104-14. [DOI: 10.1016/j.jip.2012.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 12/21/2012] [Accepted: 12/24/2012] [Indexed: 01/10/2023]
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Kupferschmied P, Maurhofer M, Keel C. Promise for plant pest control: root-associated pseudomonads with insecticidal activities. FRONTIERS IN PLANT SCIENCE 2013; 4:287. [PMID: 23914197 PMCID: PMC3728486 DOI: 10.3389/fpls.2013.00287] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/12/2013] [Indexed: 05/20/2023]
Abstract
Insects are an important and probably the most challenging pest to control in agriculture, in particular when they feed on belowground parts of plants. The application of synthetic pesticides is problematic owing to side effects on the environment, concerns for public health and the rapid development of resistance. Entomopathogenic bacteria, notably Bacillus thuringiensis and Photorhabdus/Xenorhabdus species, are promising alternatives to chemical insecticides, for they are able to efficiently kill insects and are considered to be environmentally sound and harmless to mammals. However, they have the handicap of showing limited environmental persistence or of depending on a nematode vector for insect infection. Intriguingly, certain strains of plant root-colonizing Pseudomonas bacteria display insect pathogenicity and thus could be formulated to extend the present range of bioinsecticides for protection of plants against root-feeding insects. These entomopathogenic pseudomonads belong to a group of plant-beneficial rhizobacteria that have the remarkable ability to suppress soil-borne plant pathogens, promote plant growth, and induce systemic plant defenses. Here we review for the first time the current knowledge about the occurrence and the molecular basis of insecticidal activity in pseudomonads with an emphasis on plant-beneficial and prominent pathogenic species. We discuss how this fascinating Pseudomonas trait may be exploited for novel root-based approaches to insect control in an integrated pest management framework.
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Affiliation(s)
- Peter Kupferschmied
- Department of Fundamental Microbiology, University of LausanneLausanne, Switzerland
| | - Monika Maurhofer
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology ZurichZurich, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of LausanneLausanne, Switzerland
- *Correspondence: Christoph Keel, Department of Fundamental Microbiology, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland e-mail:
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Abdul-Ghani R, Al-Mekhlafi AM, Alabsi MS. Microbial control of malaria: biological warfare against the parasite and its vector. Acta Trop 2012; 121:71-84. [PMID: 22100545 DOI: 10.1016/j.actatropica.2011.11.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 10/31/2011] [Accepted: 11/04/2011] [Indexed: 01/31/2023]
Abstract
Microbial applications in malaria transmission control have drawn global attention. Mosquito midgut microbiota can modulate vector immunity and block Plasmodium development. Paratransgenic manipulation of bacterial symbionts and Wolbachia can affect reproductive characteristics of mosquitoes. Bacillus-based biolarvicides can control mosquito larvae in different breeding habitats, but their effectiveness differs according to the type of formulation applied, and the physical and ecological conditions of the environment. Entomopathogenic fungi show promise as effective and evolution-proof agents against adult mosquitoes. In addition, transgenic fungi can express anti-plasmodial effector molecules that can target the parasite inside its vector. Despite showing effectiveness in domestic environments as well as against insecticide-resistant mosquitoes, claims towards their deployability in the field and their possible use in integrated vector management programmes have yet to be investigated. Viral pathogens show efficacy in the interruption of sporogonic development of the parasite, and protozoal pathogens exert direct pathogenic potential on larvae and adults with substantial effects on mosquito longevity and fecundity. However, the technology required for their isolation and maintenance impedes their field application. Many agents show promising findings; however, the question remains about the epidemiologic reality of these approaches because even those that have been tried under field conditions still have certain limitations. This review addresses aspects of the microbial control of malaria between proof-of-concept and epidemiologic reality.
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Péchy-Tarr M, Bruck DJ, Maurhofer M, Fischer E, Vogne C, Henkels MD, Donahue KM, Grunder J, Loper JE, Keel C. Molecular analysis of a novel gene cluster encoding an insect toxin in plant-associated strains of Pseudomonas fluorescens. Environ Microbiol 2008; 10:2368-86. [PMID: 18484997 DOI: 10.1111/j.1462-2920.2008.01662.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Pseudomonas fluorescens CHA0 and the related strain Pf-5 are well-characterized representatives of rhizosphere bacteria that have the capacity to protect crop plants from fungal root diseases, mainly by releasing a variety of exoproducts that are toxic to plant pathogenic fungi. Here, we report that the two plant-beneficial pseudomonads also exhibit potent insecticidal activity. Anti-insect activity is linked to a novel genomic locus encoding a large protein toxin termed Fit (for P. fluorescensinsecticidal toxin) that is related to the insect toxin Mcf (Makes caterpillars floppy) of the entomopathogen Photorhabdus luminescens, a mutualist of insect-invading nematodes. When injected into the haemocoel, even low doses of P. fluorescens CHA0 or Pf-5 killed larvae of the tobacco hornworm Manduca sexta and the greater wax moth Galleria mellonella. In contrast, mutants of CHA0 or Pf-5 with deletions in the Fit toxin gene were significantly less virulent to the larvae. When expressed from an inducible promoter in a non-toxic Escherichia coli host, the Fit toxin gene was sufficient to render the bacterium toxic to both insect hosts. Our findings establish the Fit gene products of P. fluorescens CHA0 and Pf-5 as potent insect toxins that define previously unappreciated anti-insect properties of these plant-colonizing bacteria.
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Affiliation(s)
- Maria Péchy-Tarr
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
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Chapuisat M, Oppliger A, Magliano P, Christe P. Wood ants use resin to protect themselves against pathogens. Proc Biol Sci 2007; 274:2013-7. [PMID: 17535794 PMCID: PMC2275180 DOI: 10.1098/rspb.2007.0531] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 05/08/2007] [Accepted: 05/08/2007] [Indexed: 11/12/2022] Open
Abstract
Social life is generally associated with an increased exposure to pathogens and parasites, due to factors such as high population density, frequent physical contact and the use of perennial nest sites. However, sociality also permits the evolution of new collective behavioural defences. Wood ants, Formica paralugubris, commonly bring back pieces of solidified coniferous resin to their nest. Many birds and a few mammals also incorporate green plant material into their nests. Collecting plant material rich in volatile compounds might be an efficient way to fight bacteria and fungi. However, no study has demonstrated that this behaviour has a positive effect on survival. Here, we provide the first experimental evidence that animals using plant compounds with antibacterial and antifungal properties survive better when exposed to detrimental micro-organisms. The presence of resin strongly improves the survival of F. paralugubris adults and larvae exposed to the bacteria Pseudomonas fluorescens, and the survival of larvae exposed to the entomopathogenic fungus Metarhizium anisopliae. These results show that wood ants capitalize on the chemical defences which have evolved in plants to collectively protect themselves against pathogens.
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Affiliation(s)
- Michel Chapuisat
- Department of Ecology and Evolution, Biophore, UNIL-Sorge, University of Lausanne, 1015 Lausanne, Switzerland.
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Malik A, Singh N, Satya S. House fly (Musca domestica): a review of control strategies for a challenging pest. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2007; 42:453-69. [PMID: 17474025 DOI: 10.1080/03601230701316481] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Musca domestica L. (Diptera: Muscidae), commonly called the house fly, is a major domestic, medical and veterinary pest that causes irritation, spoils food and acts as a vector for many pathogenic organisms. In this paper, the social and health problems related to housefly are introduced with the associated need to control its population. Physical and chemical methods of house fly control are briefly discussed. The main focus of this review is on the biological control methods for house fly control, that comprise botanical, fungal, bacterial and parasitoid agents. Although several biocontrol agents are still in the nascent stage, some of them (especially fungal and parasitoid agents) have shown reliable field performance and seem to be suitable candidates for commercialization. However, the majority of these laboratory and field studies have been conducted in the temperate region. It remains to be seen whether the application of biocontrol agents would be feasible in tropical environments. The integrated pest management practices, which can provide more reliable field performance, have also been discussed. A multi-dimensional approach that exerts control on all the life stages of house fly, but simultaneously preserves the fly's natural enemies could be an ecologically sustainable way of maintaining the fly populations below maximally acceptable limits.
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Affiliation(s)
- Anushree Malik
- Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India.
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Upadhyay RK, Rohatgi L, Chaubey MK, Jain SC. Ovipositional responses of the pulse beetle, Bruchus chinensis (Coleoptera: Bruchidae) to extracts and compounds of Capparis decidua. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:9747-51. [PMID: 17177496 DOI: 10.1021/jf0608367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Extracts of Capparis decidua stems and flowers showed insecticidal and oviposition inhibitory activities against Bruchus chinensis. The LC50 values of these extracts were found to increase with the increase in the polarity of the extract at different exposure periods. For instance, after 96 h, the LC50 values were found to be 3.619, 7.319, and 10.151 microg for CD1, CD2, and CD3, respectively. Extract CD7 was effective only at higher doses. The toxicity was found to be dose- and time-dependent. The females laid lesser number of eggs, when exposed to sublethal doses of different extracts and pure compounds, as compared to control. The maximum oviposition deterrence index was found for extract CD1 followed in decreasing order by CD2, CD3, and CD7. From extract CD1, two compounds were isolated and characterized as triacontanol (C1) and 2-carboxy-1,1-dimethylpyrrolidine (C2). When the females were exposed to sublethal doses of these compounds, they laid lesser number of eggs as compared to the control. C2 was found to have a slightly greater oviposition inhibition effect than C1. From fraction CD7, one novel compound labeled as CDF1 has been isolated and identified as 6-(1-hydroxy-non-3-enyl)tetrahydropyran-2-one. CDF1 has also shown insecticidal and oviposition inhibitory activities against B. chinensis at low concentrations.
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Affiliation(s)
- Ravi K Upadhyay
- Department of Zoology, DDU Gorakhpur University, Gorakhpur 273009, India
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Sadanandane C, Reddy CMR, Prabakaran G, Balaraman K. Field evaluation of a formulation of Pseudomonas fluorescens against Culex quinquefasciatus larvae and pupae. Acta Trop 2003; 87:341-3. [PMID: 12875927 DOI: 10.1016/s0001-706x(03)00154-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
VCRC B426, 0.09% emulsifiable concentrate (EC) formulation developed from a metabolite of Pseudomonas fluorescens was tested for efficacy against Culex quinquefasciatus larvae and pupae. At application rates of 100, 200, 300 ml/m2, the formulation caused 100% elimination of larvae and pupae at day 1 after treatments and >80% reduction in pupal density for periods of 7, 12 and 11 days in cesspits and 5, 9 and 10 days in U-shaped drains. In both the habitats, the efficacy of the formulation against pupae was 1.7 times more at 200 ml/m2 than at 100 ml/m2. An increase in dosage to 300 ml/m2 did not improve the efficacy in cesspits but a marginal increase was observed in drains.
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Affiliation(s)
- C Sadanandane
- Vector Control Research Centre (ICMR), Medical Complex, Indira Nagar, Pondicherry 605 006, India.
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