Antimicrobial and Insecticidal: Cyclic Lipopeptides and Hydrogen Cyanide Produced by Plant-Beneficial Pseudomonas Strains CHA0, CMR12a, and PCL1391 Contribute to Insect Killing.

Détails

Ressource 1Télécharger: fmicb-08-00100.pdf (1485.21 [Ko])
Etat: Serval
Version: Final published version
ID Serval
serval:BIB_244F7F17A529
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Antimicrobial and Insecticidal: Cyclic Lipopeptides and Hydrogen Cyanide Produced by Plant-Beneficial Pseudomonas Strains CHA0, CMR12a, and PCL1391 Contribute to Insect Killing.
Périodique
Frontiers in microbiology
Auteur(s)
Flury P., Vesga P., Péchy-Tarr M., Aellen N., Dennert F., Hofer N., Kupferschmied K.P., Kupferschmied P., Metla Z., Ma Z., Siegfried S., de Weert S., Bloemberg G., Höfte M., Keel C.J., Maurhofer M.
ISSN-L
1664-302X
Statut éditorial
Publié
Date de publication
2017
Peer-reviewed
Oui
Volume
8
Pages
100
Langue
anglais
Notes
Publication types: Journal Article
Publication Status: epublish
Résumé
Particular groups of plant-beneficial fluorescent pseudomonads are not only root colonizers that provide plant disease suppression, but in addition are able to infect and kill insect larvae. The mechanisms by which the bacteria manage to infest this alternative host, to overcome its immune system, and to ultimately kill the insect are still largely unknown. However, the investigation of the few virulence factors discovered so far, points to a highly multifactorial nature of insecticidal activity. Antimicrobial compounds produced by fluorescent pseudomonads are effective weapons against a vast diversity of organisms such as fungi, oomycetes, nematodes, and protozoa. Here, we investigated whether these compounds also contribute to insecticidal activity. We tested mutants of the highly insecticidal strains Pseudomonas protegens CHA0, Pseudomonas chlororaphis PCL1391, and Pseudomonas sp. CMR12a, defective for individual or multiple antimicrobial compounds, for injectable and oral activity against lepidopteran insect larvae. Moreover, we studied expression of biosynthesis genes for these antimicrobial compounds for the first time in insects. Our survey revealed that hydrogen cyanide and different types of cyclic lipopeptides contribute to insecticidal activity. Hydrogen cyanide was essential to full virulence of CHA0 and PCL1391 directly injected into the hemolymph. The cyclic lipopeptide orfamide produced by CHA0 and CMR12a was mainly important in oral infections. Mutants of CMR12a and PCL1391 impaired in the production of the cyclic lipopeptides sessilin and clp1391, respectively, showed reduced virulence in injection and feeding experiments. Although virulence of mutants lacking one or several of the other antimicrobial compounds, i.e., 2,4-diacetylphloroglucinol, phenazines, pyrrolnitrin, or pyoluteorin, was not reduced, these metabolites might still play a role in an insect background since all investigated biosynthetic genes for antimicrobial compounds of strain CHA0 were expressed at some point during insect infection. In summary, our study identified new factors contributing to insecticidal activity and extends the diverse functions of antimicrobial compounds produced by fluorescent pseudomonads from the plant environment to the insect host.

Mots-clé
orfamide, sessilin, Gac regulatory system, Pseudomonas fluorescens, Pseudomonas protegens, Pseudomonas chlororaphis, secondary metabolites, insecticidal activity
Pubmed
Création de la notice
23/02/2017 9:17
Dernière modification de la notice
03/03/2018 14:58
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