The role of chloroplast-generated reactive oxygen species in the response to plant-pathogen interactions

DELPRATO ML, BÍSARO F, KRAPP AR AND CARRILLO N

Chascomús

Jornada; XV JORNADAS ANUALES DE LA SOCIEDAD ARGENTINA DE BIOLOGÍA; 2013

SOCIEDAD ARGENTINA DE BIOLOGÍA

Plants react against pathogen challenges by deploying complex responses that involve expression of multiple genes and the hypersensitive reaction (HR). As a result, there is a concomitant production of reactive oxygen species (ROS) in various cellular compartments. In this work we used tobacco plants expressing a cyanobacterial flavodoxin in chloroplasts, which showed increased tolerance to multiple adverse environmental conditions and lower ROS accumulation because flavodoxin acts as a general antioxidant. We used these plants to study if the HR light requirements are linked to ROS production in chloroplasts. We report here the phenotypic and biochemical characterization of the interaction between these plants and pathovars of Pseudomonas syringae that represent the non host, virulent and avirulent interactions, in the presence or in the absence of light. ROS quantification by fluorescent microscopy indicated that the transgenic plants accumulated lower levels of ROS and suffered less damage than the wild type, but only if light was present. The results lend support to models that indicate the participation of plastid-generated ROS in the defense response of plants against pathogens.