Open AccessThe R sm regulon of plant growth‐promoting P seudomonas fluorescens SS 101: role of small RNA s in regulation of lipopeptide biosynthesis
Author(s) -
Song Chunxu,
Voort Menno,
Mortel Judith,
Hassan Karl A.,
Elbourne Liam D. H.,
Paulsen Ian T.,
Loper Joyce E.,
Raaijmakers Jos M.
Publication year - 2015
Publication title -
microbial biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.287
H-Index - 74
ISSN - 1751-7915
DOI - 10.1111/1751-7915.12190
Subject(s) - regulon , biology , transcriptome , gene , repressor , genetics , in silico , regulation of gene expression , gene expression
Summary The rhizobacterium P seudomonas fluorescens SS 101 inhibits growth of oomycete and fungal pathogens, and induces resistance in plants against pathogens and insects. To unravel regulatory pathways of secondary metabolite production in SS 101, we conducted a genome‐wide search for sRNAs and performed transcriptomic analyses to identify genes associated with the R sm ( r epressor of secondary metabolites) regulon. In silico analysis led to the identification of 16 putative sRNAs in the SS 101 genome. In frame deletion of the sRNAs rsmY and rsmZ showed that the R sm system regulates the biosynthesis of the lipopeptide massetolide A and involves the two repressor proteins RsmA and RsmE , with the LuxR ‐type transcriptional regulator MassAR as their most likely target. Transcriptome analyses of the rsmYZ mutant further revealed that genes associated with iron acquisition, motility and chemotaxis were significantly upregulated, whereas genes of the type VI secretion system were downregulated. Comparative transcriptomic analyses showed that most, but not all, of the genes controlled by RsmY / RsmZ are also controlled by the GacS / GacA two‐component system. We conclude that the R sm regulon of P. fluorescens SS 101 plays a critical role in the regulation of lipopeptide biosynthesis and controls the expression of other genes involved in motility, competition and survival in the plant rhizosphere.