Abstract: 【Objective】Tobacco BY-2 cell was used to explore the effect of the Alternaria alternata metabolic products (MP) on changes of reactive oxygen species (ROS ) production and ATP content in the tobacco BY-2 cells.【Method】10% MP was used to treat tobacco BY-2 cells, and Oxytherm oxygen electrode was used to study the effects of MP on the reparation rate and reparation pathway in the tobacco BY-2 cells. The changes of ROS production and ATP content in tobacco BY-2cells was also studied.【Result】Treatment with the MP led to remarkable overproduction of ROS, rapid depletion of ATP, significant declines in respiration , in cytochrome pathway and in alternative oxidase pathway (AOX). The treatment with MP also resulted in uncoupling of oxidative phosphorylation, opening of the permeability transition pore (PTP) and release of cytochrome c from mitochondria to cytoplasm in tobacco BY-2 cells,.【Conclusion】The inhibition of respiration and cytochrome pathway inevitably resulted in ATP depletion in tobacco BY-2 cells. The uncoupling of oxidative phosphorylation induced by MP is another contributor to the ATP depletion.Besides, the inhibition of AOX pathway by the MP treatment is one of the main reasons to lead to the ROS burst in tobacco BY-2 cells.

Key words: Tobacco BY-2 cells, Metabolic products of Alternariata alternata, ROS burst, ATP depletion, Mitochondrial PTP opening, Cytochrome c release