Mitochondrial bioenergetics linked to the manifestation of programmed cell death during somatic embryogenesis of Abies alba.
The present work reports changes in bioenergetic parameters and mitochondrial activities during the manifestation of two events of programmed cell death (PCD), linked to Abies alba somatic embryogenesis. PCD, evidenced by in situ nuclear DNA fragmentation (TUNEL assay), DNA laddering and cytochrome c release, was decreased in maturing embryogenic tissue with respect to the proliferation stage. In addition, the major cellular energetic metabolites (ATP, NAD(P)H and glucose-6-phosphate) were highered during maturation. The main mitochondrial activities changed during two developmental stages. Mitochondria, isolated from maturing, with respect to proliferating cell masses, showed an increased activity of the alternative oxidase, external NADH dehydrogenase and fatty-acid mediated uncoupling. Conversely, a significant decrease of the mitochondrial K (ATP)(+) channel activity was observed. These results suggest a correlation between mitochondrial activities and the manifestation of PCD during the development of somatic embryos. In particular, it is suggested that the K (ATP)(+) channel activity could induce an entry of K(+) into the matrix, followed by swelling and a release of cytochrome c during proliferation, whereas the alternative pathways, acting as anti-apoptotic factors, may partially counteract PCD events occurring during maturation of somatic embryos.
Petrussa
Elisa
E
Section of Plant Biology, Department of Biology and Plant Protection, University of Udine, via delle Scienze 91, 33100, Udine, Italy.
Bertolini
Alberto
A
Casolo
Valentino
V
Krajnáková
Jana
J
Macrì
Francesco
F
Vianello
Angelo
A
D028202:Abies / Q000166:cytology* / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D019069:Cell Respiration / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005227:Fatty Acids / Q000494:pharmacology; D019298:Glucose-6-Phosphate / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D024101:Mitochondrial Proteins; D009249:NADP / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010940:Plant Proteins; D015221:Potassium Channels / Q000378:metabolism; D000099188:Alternative Oxidase
D000255:Adenosine Triphosphate; D045304:Cytochromes c; D005227:Fatty Acids; D019298:Glucose-6-Phosphate; D024101:Mitochondrial Proteins; D009249:NADP; D010088:Oxidoreductases; D010100:Oxygen; D010940:Plant Proteins; D015221:Potassium Channels; D000099188:Alternative Oxidase; C117780:mitochondrial K(ATP) channel