Abstract
Pseudomonas corrugata and Pseudomonas mediterranea are two closely related phytopathogenic bacteria both causal agents of tomato pith necrosis. P. corrugata
produces phytotoxic and antimicrobial cationic lipodepsipeptides (LDPs)
which are thought to act as major virulence factors. Previous studies
have demonstrated that P. corrugata CFBP 5454 has an N-acyl
homoserine lactone (AHL) quorum sensing (QS) system PcoI/PcoR and that
LDP production occurs at high population densities. No molecular studies
on virulence have thus far been reported for P. mediterranea. In this study, we show that P. mediterranea
also produces LDPs as well as possessing an AHL-dependent QS system,
designated PmeI/PmeR, which is highly homologous to the PcoI/R system of
P. corrugata producing and responding to C6-AHL. Downstream of pmeI, a partial DNA sequence revealed the presence of a homolog of the rfiA gene of P. corrugata
which encodes a transcriptional regulator involved in bacterial
virulence. Pathogenicity tests and MALDI-TOF spectra of wild-type
strains of both bacterial species and their respective QSs and rfiA
derivative mutants revealed that, in the absence of LDPs, the strains
induce very weak symptoms indicating that LDPs may act as major
virulence factors. Mutational analysis of both QS systems suggests that
their mode of action is in places different.
Original language | English |
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Pages (from-to) | 274-282 |
Number of pages | 9 |
Journal | Journal of Biotechnology |
Volume | 159 |
Issue number | 4 |
DOIs | |
Publication status | Published - 30 Jun 2012 |
Externally published | Yes |
Keywords
- Pseudomonas mediterranea
- Pseudomonas corrugata
- Quorum sensing
- Lipodepsipeptides
- Virulence
- Tomato