SECRETION OF PUTRESCINE BY PSEUDOMONAS SYRINGAE FUNCTIONS AS AN ANTIOXIDANT DEFENSE DURING PLANT INVASION

LEANDRO SOLMI; FRANCO ROSSI; FERNANDO MATÍAS ROMERO; OSCAR ADOLFO RUIZ; ANDRES GÁRRIZ

Congreso; XXXII Reunión Argentina y XVI Congreso Latinoamericano de Fisiología Vegetal; 2018

Polyamines such as putrescine, spermidine and spermine are important for virulence in phytopathogens. In this work, we were prompted to explore whether thesecretion of this polyamine by P. syringae functions to cope with oxidative stress. Our analysis demonstrated that bacterial growth is affected by sub lethalconcentrations of H2O2. In addition, P. syringae induced the secretion of putrescine in response to this oxidative environment, leading to the increase in itsconcentration at the extracellular space. Disruption of polyamine biosynthetic genes led to an increase of intracellular reactive oxygen species, demonstrating thatthese compounds are involved in maintaining redox homeostasis. Nevertheless, the addition of putrescine to culture media was not able to ameliorate the effects ofoxidative stress neither restore bacterial growth in the presence of H2O2. These results shed more light to the roles played by polyamines during bacterialpathogenesis.