The defence elicitor AsES causes a rapid and transient membrane depolarization, a triphasic oxidative burst and the acumulation of nitric oxide

GUSTAVO GABRIEL MARTOS; MARÍA DEL MILAGRO TERÁN; JUAN CARLOS DIAZ RICCI

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2015

0981-9428

The newly characterized elicitor AsES obtained from Acremonium strictum induces a strong defenceresponse in strawberry plants and confers plants resistance against the fungal pathogen Colletotricumacutatum the casual agent of anthracnose disease. Previous studies showed that AsES causes theaccumulation of reactive oxygen species (ROS) that peaked 4 hour post treatment (hpt), but due tothe experimental approach used it was not clear whether the accumulation of ROS observed wasintracellular or extracellular or took place as a single peak. By using a different experimental setup, amore complex early events associated to the activation of the innate immunity were observed. In thispaper we report that strawberry plant cells treated with AsES exhibits a triphasic production of H2O2and a rapid intracellular accumulation of NO. The first phase consists in an extracellularaccumulation of H2O2 that takes place immediately after the treatment with AsES and is preceded bya rapid and transient cell membrane depolarization. During this phase also takes place a rapidintracellular accumulation of NO. Microscopic observations of mesophyll cells treated with AsESshowed that NO accumulates at the chloroplast. After the first extracellular H2O2 production phase,two intracellular H2O2 accumulation events occur, the first 2 hpt, and the second 7 hpt. Cell treatedwith AsES also showed a progressive alkalinization of the extracellular medium.