Link to home

Quorum sensing systems in Dickeya solani with different virulence levels.

Marta Potrykus: Intercollegiate Faculty of Biotechnology University of Gdansk Medical University of Gdansk

<div><em>Dickeya solani</em> is a highly homogenous species at the genomic level but single strains differ in their virulence level. Two quorum sensing (QS) mechanisms were described so far in <em>Dickeya</em> spp.: classic QS based on N-acyl-homoserine lactone (AHL) signals utilized by different microorganisms, and a specific Virulence Factor Modulating QS (VFM-QS) used exclusively by <em>Dickeya</em> genus. In this study, the influence of both QS on the <em>D. solani</em> virulence has been verified by mutagenesis. Single mutants inactivated in <em>vfmA, vfmE, vfmH,</em> <em>vfmI</em> and<em> vfmK </em>genes as well as <em>expI</em> and <em>expR</em> genes were constructed via transduction. Moreover, double mutants of both QS systems (<em>vfmI/E-expI/R</em>) were obtained. All mutants were evaluated for their ability to macerate plant tissue, pectate lyase, protease and cellulase activities, as well as swimming and swarming capacity. For some of the mutants, the difference in the phenotypes was verified with Omnilog<sup>R</sup> Phenotype Microarrays PM1-10 plates. In most <em>D. solani</em> strains, the <em>expI/R</em> mutations caused a decrease in chicory maceration, with a stronger effect for <em>expR</em> than for <em>expI</em>. Similarly, all <em>D. solani</em> <em>vfm</em> mutants showed an attenuation of chicory maceration as well as decreased protease and cellulase activity. No additive effect on tested features was observed in double mutants background. Thus, no synergy between VFM- and AHL-QS is observed in fine-tuning the production of different virulence factors and the ability to macerate plant tissue.</p> <p> </p> <p>Acknowledgements</p> <p>The work was supported by Polish National Science Center with the project UMO-2014/14/M/NZ8/00501 and UMO-2014/13/N/NZ9/01081.</div>