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Characterization of the SPI ‐1 and R sp type three secretion systems in P seudomonas fluorescens F 113
Author(s) -
Barret Matthieu,
Egan Frank,
Moynihan Jennifer,
Morrissey John P.,
Lesouhaitier Olivier,
O'Gara Fergal
Publication year - 2013
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12039
Subject(s) - pseudomonas fluorescens , biology , gene , secretion , effector , rhizosphere , microbiology and biotechnology , genetics , bacteria , biochemistry
Summary P seudomonas fluorescens F 113 is a plant growth‐promoting rhizobacterium ( PGPR ) isolated from the sugar beet rhizosphere. The recent annotation of the F 113 genome sequence has revealed that this strain encodes a wide array of secretion systems, including two complete type three secretion systems ( T3SS s) belonging to the H rp1 and SPI ‐1 families. While H rp1 T3SS s are frequently encoded in other P . fluorescens strains, the presence of a SPI ‐1 T3SS in a plant‐beneficial bacterial strain was unexpected. In this work, the genetic organization and expression of these two T3SS loci have been analysed by a combination of transcriptional reporter fusions and transcriptome analyses. Overexpression of two transcriptional activators has shown a number of genes encoding putative T 3 effectors. In addition, the influence of these two T3SS s during the interaction of P . fluorescens F 113 with some bacterial predators was also assessed. Our data revealed that the transcriptional activator hilA is induced by amoeba and that the SPI ‐1 T3SS could potentially be involved in resistance to amoeboid grazing.