V. Houot et al., Hydrogen peroxide induces programmed cell death features in cultured tobacco BY-2 cells, in a dose-dependent manner, J EXP BOT, 52(361), 2001, pp. 1721-1730
Active oxygen species (AOS), especially hydrogen peroxide, play a critical
role in the defence of plants against invading pathogens and in the hyperse
nsitive response (HR). This is characterized by the induction of a massive
production of AOS and the rapid appearance of necrotic lesions is considere
d as a programmed cell death (PCD) process during which a limited number of
cells die at the site of infection. This work was aimed at investigating t
he mode of cell death observed in cultures of BY-2 tobacco cells exposed to
H2O2. It was shown that H2O2 is able to induce various morphological cell
death features in cultured tobacco BY-2 cells. The hallmarks of cell death
observed with fluorescent and electron microscopy differed greatly with the
amount of H2O2 added to the cell culture. The appearance of nuclear fragme
ntation similar to 'apoptotic bodies' associated with a fragmentation of th
e nuclear DNA into small fragments appear for almost 18% of the cells treat
ed with 12.5 mM H2O2. The early stages of the induction of this PCD process
consisted in cell shrinkage and chromatin condensation at the periphery of
the nucleus. Above 50 mM, H2O2 induces high necrotic cell death. These dat
a suggest that H2O2-induced cell damage is associated with the induction of
various cell death processes that could be involved differently in plant d
efence reactions.