Short-term salinity stress in tobacco plants leads to the onset of animal-like PCD hallmarks in planta in contrast to long-term stress.
Recent results have identified mitochondria as centers of stress-induced generation of reactive oxygen species in plants. Depolarization of plant mitochondrial membrane during stress results the release of programmed cell death (PCD)-inducing factors in the cytosol in a fashion similar to the onset of animal-like PCD. Herein, we report significant similarities of animal-like PCD and salinity stress-induced plant PCD. Short-term salinity stress (3 h) led to depolarization of the mitochondrial membrane, release of cytochrome c (CYT-c), which was visualized using a contemporary molecular technique, activation of caspase-3 type proteases and the onset of PCD in wild type tobacco plants, Nicotiana tabacum cv. Petit Havana. However, PCD was not manifested during long-term salinity stress (24 h). Interestingly long-term salinity stress led to necrotic-like features, which were accompanied by collapse of respiration, reduction of key components of the respiratory chain, such as CYT-c and alternative oxidase, ATP depletion and high proteolytic activity. The results suggest that salinity stress of tobacco plants in planta leads to the onset of animal-like PCD only during the early stages post-stress, while long-term stress leads to necrotic-like features.
Andronis
Efthimios A
EA
Department of Biology, University of Crete, P.O. Box 2208, 71409 Heraklion Crete, Greece. e_andronis@yahoo.co.uk
Roubelakis-Angelakis
Kalliopi A
KA
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D054712:Salinity; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D014026:Nicotiana / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology
D013481:Superoxides; D012965:Sodium Chloride; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D053148:Caspase 3