Fungal elicitor induces hypersensitive response and systemic oxidative burst in strawberry plants

CHALFOUN NADIA REGINA; CASTAGNARO ATILIO PEDRO; DÍAZ RICCI JUAN CARLOS

Pinamar, Bs. As. Rep. Argentina

Congreso; XLI Reunión Anual de SAIB (Sociedad Argentina de Investigación en Bioquímica y Biología Molecular) - X Congreso de PABMB - XX Reunión Anual de SAN; 2005

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The recognition of a defense elicitor stimulates an oxidative burst generating reactive oxygen species (ROS) that induce defense genes and localized cell death restricted to the lesion zone. This hypersensitive response (HR) is accompanied by the development of resistance to virulent pathogens. The aim of this study was to analyze in strawberry plants, the production of two reactive oxygen species (O2- and H2O2) and HR in response to a fungal elicitor obtained from an avirulent strain of Colletotrichum fragariae. The extract containing the elicitor (20 ul) was infiltrated on the abaxial surface of one leaflet per plant of the cultivar Pájaro. Results indicate that two hours after the application of the elicitor, ROS species such as O2- and H2O2 accumulate in the inoculated leaflet and not inoculated proximal and distal tissues, suggesting the induction of a systemic cellular response. Two days after the infiltration we have observed the formation of necrotic lesions restricted to the infiltrated zone, that closely resemble the HR. A strong epifluorescence located in cells surrounding the necrotic lesion, was also observed, indicating the accumulation of compounds derived from the phenylpropanoid pathway, highly stimulated during the HR. Plant cells recognizing the elicitor induced a cascade of short and long distance signals that are currently being under study in our laboratory.