Switching between apparently redundant iron-uptake mechanisms benefits bacteria in changeable environments.

Détails

ID Serval
serval:BIB_0DBDC59AFFE8
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Switching between apparently redundant iron-uptake mechanisms benefits bacteria in changeable environments.
Périodique
Proceedings of the Royal Society B Biological Sciences
Auteur(s)
Dumas Z., Ross-Gillespie A., Kümmerli R.
ISSN
1471-2954 (Electronic)
ISSN-L
0962-8452
Statut éditorial
Publié
Date de publication
2013
Volume
280
Numéro
1764
Pages
20131055
Langue
anglais
Résumé
Bacteria often possess multiple siderophore-based iron uptake systems for scavenging this vital resource from their environment. However, some siderophores seem redundant, because they have limited iron-binding efficiency and are seldom expressed under iron limitation. Here, we investigate the conundrum of why selection does not eliminate this apparent redundancy. We focus on Pseudomonas aeruginosa, a bacterium that can produce two siderophores-the highly efficient but metabolically expensive pyoverdine, and the inefficient but metabolically cheap pyochelin. We found that the bacteria possess molecular mechanisms to phenotypically switch from mainly producing pyoverdine under severe iron limitation to mainly producing pyochelin when iron is only moderately limited. We further show that strains exclusively producing pyochelin grew significantly better than strains exclusively producing pyoverdine under moderate iron limitation, whereas the inverse was seen under severe iron limitation. This suggests that pyochelin is not redundant, but that switching between siderophore strategies might be beneficial to trade off efficiencies versus costs of siderophores. Indeed, simulations parameterized from our data confirmed that strains retaining the capacity to switch between siderophores significantly outcompeted strains defective for one or the other siderophore under fluctuating iron availabilities. Finally, we discuss how siderophore switching can be viewed as a form of collective decision-making, whereby a coordinated shift in behaviour at the group level emerges as a result of positive and negative feedback loops operating among individuals at the local scale.
Mots-clé
on uptake, siderophore, trade-off, fluctuating environment, phenotypic plasticity, decision-making
Pubmed
Web of science
Open Access
Oui
Création de la notice
14/08/2013 9:25
Dernière modification de la notice
08/05/2019 14:23
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