Mitochondrial behaviour in the early stages of ROS stress leading to cell death in Arabidopsis thaliana.
OBJECTIVE
Reactive oxygen species (ROS) are involved in triggering cell death. To visualize mitochondrial behaviour under ROS stress, transgenic arabidopsis plants possessing mitochondrial-targeted GFP (S65T) were studied.


METHODS
Arabidopsis leaves were treated with ROS and ROS-inducing chemicals such as hydrogen peroxide, paraquat and menadione. Microscopic observations were carried out using a confocal laser scanning microscope system, and electrolyte leakage was also monitored.


RESULTS
After treatment, mitochondria showed morphological changes from a bacillus-like to a round shape. The size of mitochondria treated with H(2)O(2) decreased by half compared with controls. Concurrently, cytoplasmic streaming was blocked and mitochondria eventually swelled. Treatment of leaves with butanedione monoxime, an inhibitor of myosin ATPase, resulted in similar behaviour of mitochondria to that under ROS stress.


CONCLUSIONS
The results indicate that morphological changes of mitochondria and cessation of cytoplasmic streaming may interact, and this phenomenon is one of the features of ROS stress-induced cell death.
Yoshinaga
Keiko
K
Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Arimura
Shin-ichi
S
Niwa
Yasuo
Y
Tsutsumi
Nobuhiro
N
Uchimiya
Hirofumi
H
Kawai-Yamada
Maki
M
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D003595:Cytoplasmic Streaming / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009218:Myosins / Q000037:antagonists & inhibitors; D010269:Paraquat / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism*; D024483:Vitamin K 3 / Q000494:pharmacology
D017382:Reactive Oxygen Species; D049452:Green Fluorescent Proteins; D024483:Vitamin K 3; D006861:Hydrogen Peroxide; D009218:Myosins; D010269:Paraquat