title: Characterization of Rubus fruticosus mitochondria and salicylic acid inhibition of reactive oxygen species generation at Complex III/Q cycle: potential implications for hypersensitive response in plants.
abstract: In addition to adenosine triphosphate (ATP) production, mitochondria have been implicated in the regulation of several physiological responses in plants, such as programmed cell death (PCD) activation. Salicylic acid (SA) and reactive oxygen species (ROS) are essential signaling molecules involved in such physiological responses; however, the mechanisms by which they act remain unknown. In non-photosynthesizing tissues, mitochondria appear to serve as the main source of ROS generation. Evidence suggests that SA and ROS could regulate plant PCD through a synergistic mechanism that involves mitochondria. Herein, we isolate and characterize the mitochondria from non-photosynthesizing cell suspension cultures of Rubus fruticosus. Furthermore, we assess the primary site of ROS generation and the effects of SA on isolated organelles. Mitochondrial Complex III was found to be the major source of ROS generation in this model. In addition, we discovered that SA inhibits the electron transport chain by inactivating the semiquinone radical during the Q cycle. Computational analyses confirmed the experimental data, and a mechanism for this action is proposed.
authors: Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. Café s/n, 14040-903, Ribeirão Preto, SP, Brazil.
authors: Wagner Rodrigo
authors: WR
authors: de Souza
authors: Ricardo
authors: R
authors: Vessecchi
authors: Daniel Junqueira
authors: DJ
authors: Dorta
authors: Sérgio Akira
authors: SA
authors: Uyemura
authors: Carlos
authors: C
authors: Curti
authors: Carem Gledes
authors: CG
authors: Vargas-Rechia
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