Chromatin fragmentation associated with apoptotic changes in tobacco cells exposed to cold stress.
Programmed cell death (PCD) may be triggered by a variety of environmental stimuli. In this report we show that low temperature treatment of tobacco BY-2 cells results in specific chromatin changes. The early stage was characterised by chromatin condensation associated with specific endonucleolytic cleavage of the genome into fragments of 50-100 kbp in size. Later, after 2 weeks of the cold treatment, a ladder of nucleosomal units (178 bp) and their multiples occurred. Chromatin changes were accompanied by a general decrease in cell viability. However, the cell culture retained about 11% of living cells even after prolonged incubation in the cold suggesting the presence of a cold-resistant population of cells. The results support the view that PCD was activated by the cold stress. We suggest that cold-stressed tobacco BY-2 culture might be a useful system for investigation of PCD in plant cells.
Koukalová
B
B
Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno. kovarik@ibp.cz
Kovarík
A
A
Fajkus
J
J
Siroký
J
J
D017209:Apoptosis; D002467:Cell Nucleus / Q000648:ultrastructure; D002478:Cells, Cultured; D002843:Chromatin / Q000648:ultrastructure*; D003080:Cold Temperature; D053938:DNA Fragmentation; D018744:DNA, Plant / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis / Q000378:metabolism; D009707:Nucleosomes / Q000648:ultrastructure; D010947:Plants, Toxic; D012335:RNA, Ribosomal / Q000096:biosynthesis; D014026:Nicotiana / Q000166:cytology / Q000502:physiology*
D002843:Chromatin; D018744:DNA, Plant; D004275:DNA, Ribosomal; D009707:Nucleosomes; D012335:RNA, Ribosomal; C065039:RNA, ribosomal, 25S