The defense response mediated by the elicitor of A. strictum does not require the apoplast

MARTOS GUSTAVO; CHALFOUN NADIA REGINA; DÍAZ RICCI JUAN CARLOS

Mendoza

Congreso; XLVIII Reunión Anual de SAIB; 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The production of reactive oxygen species (ROS) plays a crucial role in signal transduction and therefore their measurement and kinetics is a very useful tool in the study of defense response in plants. We have earlier reported the generation of H2O2 and O2.- when strawberry (Fragaria x ananassa) plants were treated with an elicitor protein produced by the fungus Acremonium scrictum. In this study we evaluated the importance of the integrity of the apoplast to elicit the defense response. We worked with mesophyll cell suspensions (1x106 cells/mL) of 8 week strawberry plants of the cv. Pájaro. Cells were obtained by leaf homogenization, separated by differential centrifugation and resuspended in W5 buffer (pH 5.6). The intracellular and extracellular levels of H2O2 were measured by fluorometry using the probes H2DFFDA and Pyranine, respectively. Results showed a rapid extracellular decrease and intracellular accumulation of H2O2 immediately after the elicitor addition, suggesting a rapid translocation of H2O2 to the cytosol. After this first event, two peaks of intracellular H2O2 accumulation were observed, one 2 hours after induction (hai) and the other 7 hai, which coincided with the results previously observed in plants demonstrating that the integrity of the apoplast is not required in the induction of the defense mechanism mediated by the elicitor.