Abstract
The mammalian apoptotic protein Bax has been shown to induce cell death in plants and yeast as well as animal cells. We recently presented the evidence that Bax-induced plant death is accompanied by ROS generation. To investigate changes of organelles, we established the transgenic Arabidopsis possessing DEX-inducible Bax and organelle-targeted GFP. Upon DEX treatment, such plants exhibited cessation of cytoplasmic streaming. With the stop of streaming, morphology of mitochondria was changed from bacilliform shape to round shape. After that, the membrane function of chloroplast and vacuole was disrupted. Early cessation of cytoplasmic streaming and morphological changes were induced by hydrogen peroxide or salicylic acid treatment. Myosin is known to be responsible for plant cytoplasmic streaming. Treatment of Arabidopsis leves with a myosin ATPase inhibitor demonstrated dose-dependent ion-leakage. This result suggests that cessation of cytoplasmic streaming may be one of the activator of plant cell death.
