Predator-prey chemical warfare determines the expression of biocontrol genes by rhizosphere-associated Pseudomonas fluorescens.

Détails

ID Serval
serval:BIB_0F10B0E2BDB9
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Predator-prey chemical warfare determines the expression of biocontrol genes by rhizosphere-associated Pseudomonas fluorescens.
Périodique
Applied and Environmental Microbiology
Auteur(s)
Jousset A., Rochat L., Scheu S., Bonkowski M., Keel C.
ISSN
1098-5336[electronic], 0099-2240[linking]
Statut éditorial
Publié
Date de publication
2010
Peer-reviewed
Oui
Volume
76
Numéro
15
Pages
5263-5268
Langue
anglais
Résumé
Soil bacteria are heavily consumed by protozoan predators, and many bacteria have evolved defense strategies such as the production of toxic exometabolites. However, the production of toxins is energetically costly and therefore is likely to be adjusted according to the predation risk to balance the costs and benefits of predator defense. We investigated the response of the biocontrol bacterium Pseudomonas fluorescens CHA0 to a common predator, the free-living amoeba Acanthamoeba castellanii. We monitored the effect of the exposure to predator cues or direct contact with the predators on the expression of the phlA, prnA, hcnA, and pltA genes, which are involved in the synthesis of the toxins, 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin, hydrogen cyanide, and pyoluteorin, respectively. Predator chemical cues led to 2.2-, 2.0-, and 1.2-fold increases in prnA, phlA, and hcnA expression, respectively, and to a 25% increase in bacterial toxicity. The upregulation of the tested genes was related to the antiprotozoan toxicity of the corresponding toxins. Pyrrolnitrin and DAPG had the highest toxicity, suggesting that bacteria secrete a predator-specific toxin cocktail. The response of the bacteria was elicited by supernatants of amoeba cultures, indicating that water-soluble chemical compounds were responsible for induction of the bacterial defense response. In contrast, direct contact of bacteria with living amoebae reduced the expression of the four bacterial toxin genes by up to 50%, suggesting that protozoa can repress bacterial toxicity. The results indicate that predator-prey interactions are a determinant of toxin production by rhizosphere P. fluorescens and may have an impact on its biocontrol potential.
Mots-clé
Acanthamoeba castellanii/drug effects, Acanthamoeba castellanii/microbiology, Bacterial Toxins/biosynthesis, Bacterial Toxins/toxicity, Gene Expression Profiling, Gene Expression Regulation, Bacterial, Pseudomonas fluorescens/physiology, Soil Microbiology
Pubmed
Web of science
Open Access
Oui
Création de la notice
05/01/2010 15:28
Dernière modification de la notice
20/08/2019 12:35
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