RsmY, a small regulatory RNA, is required in concert with RsmZ for GacA-dependent expression of biocontrol traits in Pseudomonas fluorescens CHA0.

Détails

ID Serval
serval:BIB_6EBA306A40BA
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
RsmY, a small regulatory RNA, is required in concert with RsmZ for GacA-dependent expression of biocontrol traits in Pseudomonas fluorescens CHA0.
Périodique
Molecular Microbiology
Auteur(s)
Valverde C., Heeb S., Keel C., Haas D.
ISSN
0950-382X[print], 0950-382X[linking]
Statut éditorial
Publié
Date de publication
2003
Volume
50
Numéro
4
Pages
1361-1379
Langue
anglais
Résumé
In the plant-beneficial soil bacterium and biocontrol model organism Pseudomonas fluorescens CHA0, the GacS/GacA two-component system upregulates the production of biocontrol factors, i.e. antifungal secondary metabolites and extracellular enzymes, under conditions of slow, non-exponential growth. When activated, the GacS/GacA system promotes the transcription of a small regulatory RNA (RsmZ), which sequesters the small RNA-binding protein RsmA, a translational regulator of genes involved in biocontrol. The gene for a second GacA-regulated small RNA (RsmY) was detected in silico in various pseudomonads, and was cloned from strain CHA0. RsmY, like RsmZ, contains several characteristic GGA motifs. The rsmY gene was expressed in strain CHA0 as a 118 nt transcript which was most abundant in stationary phase, as revealed by Northern blot and transcriptional fusion analysis. Transcription of rsmY was enhanced by the addition of the strain's own supernatant extract containing a quorum-sensing signal and was abolished in gacS or gacA mutants. An rsmA mutation led to reduced rsmY expression, via a gacA-independent mechanism. Overexpression of rsmY restored the expression of target genes (hcnA, aprA) to gacS or gacA mutants. Whereas mutants deleted for either the rsmY or the rsmZ structural gene were not significantly altered in the synthesis of extracellular products (hydrogen cyanide, 2,4-diacetylphloroglucinol, exoprotease), an rsmY rsmZ double mutant was strongly impaired in this production and in its biocontrol properties in a cucumber-Pythium ultimum microcosm. Mobility shift assays demonstrated that multiple molecules of RsmA bound specifically to RsmY and RsmZ RNAs. In conclusion, two small, untranslated RNAs, RsmY and RsmZ, are key factors that relieve RsmA-mediated regulation of secondary metabolism and biocontrol traits in the GacS/GacA cascade of strain CHA0.
Mots-clé
Bacterial Proteins/genetics, Bacterial Proteins/metabolism, Base Sequence, Chromosomes, Bacterial, Gene Expression Regulation, Bacterial, Genes, Regulator, Molecular Sequence Data, Mutation, Nucleic Acid Conformation, Pseudomonas fluorescens/genetics, Pseudomonas fluorescens/metabolism, RNA, Bacterial/metabolism, RNA-Binding Proteins/genetics, RNA-Binding Proteins/metabolism, Recombinant Fusion Proteins/genetics, Recombinant Fusion Proteins/metabolism, Repressor Proteins/genetics, Repressor Proteins/metabolism, Sequence Alignment
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 13:51
Dernière modification de la notice
20/08/2019 14:27
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