Molecular analysis of a novel gene cluster encoding an insect toxin in plant-associated strains of Pseudomonas fluorescens
| Autor: | Monika Maurhofer, Christoph Keel, Marcella D. Henkels, Joyce E. Loper, Kelly M. Donahue, Esther Fischer, Christelle Vogne, Maria Péchy-Tarr, Denny J. Bruck, Jürg Grunder |
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| Rok vydání: | 2008 |
| Předmět: |
DNA
Bacterial animal structures Bacterial Toxins Molecular Sequence Data Pseudomonas fluorescens Moths medicine.disease_cause Microbiology 630: Landwirtschaft Lethal Dose 50 03 medical and health sciences Pseudomonas protegens Bacterial Proteins Manduca medicine Escherichia coli Animals Pest Control Biological Ecology Evolution Behavior and Systematics 030304 developmental biology 0303 health sciences Genomic Library biology 030306 microbiology Toxin Phytopathology fungi Sequence Analysis DNA Bacterial toxin Chromosomes Bacterial Plants biology.organism_classification Galleria mellonella Manduca sexta Insect toxin Genes Bacterial Larva Multigene Family Photorhabdus |
| Zdroj: | Environmental Microbiology |
| DOI: | 10.1111/j.1462-2920.2008.01662.x |
| Popis: | Summary 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. fluorescens insecticidal toxin) that is related to the insect toxin Mcf (Makes caterpillars floppy) of the entomopathogen Photorhabdus lumine- scens, 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. |
| Databáze: | OpenAIRE |
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