Resistance inducers modulate Pseudomonas syringae pv. tomato strain DC3000 response in tomato plants

PLoS One. 2014 Sep 22;9(9):e106429. doi: 10.1371/journal.pone.0106429. eCollection 2014.


The efficacy of hexanoic acid (Hx) as an inducer of resistance in tomato plants against Pseudomonas syringae pv. tomato DC3000 was previously demonstrated, and the plant response was characterized. Because little is known about the reaction of the pathogen to this effect, the goal of the present work was to determine whether the changes in the plant defence system affect the pathogen behaviour. This work provides the first demonstration of the response of the pathogen to the changes observed in plants after Hx application in terms of not only the population size but also the transcriptional levels of genes involved in quorum sensing establishment and pathogenesis. Therefore, it is possible that Hx treatment attenuates the virulence and survival of bacteria by preventing or diminishing the appearance of symptoms and controlling the growth of the bacteria in the mesophyll. It is interesting to note that the gene transcriptional changes in the bacteria from the treated plants occur at the same time as the changes in the plants. Hx is able to alter bacteria pathogenesis and survival only when it is applied as a resistance inducer because the changes that it promotes in plants affect the bacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caproates / pharmacology*
  • Gene Expression Regulation, Bacterial / drug effects*
  • Lycopersicon esculentum / microbiology*
  • Plant Diseases / microbiology*
  • Pseudomonas syringae / drug effects*
  • Pseudomonas syringae / genetics
  • Pseudomonas syringae / metabolism


  • Caproates
  • hexanoic acid

Grant support

LS is the recipient of a PhD fellowship from the Ministerio de Educación (Grant AP2008-01064) ( This work was supported by AGL2010-22300-C03-02: National R&D Plan (, and P1•1B2013-75: Projecte d′investigació científica i desenvolupament tecnologic del Pla de promoció de la investigació de la Universitat Jaume I ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.