Reactivation of mitochondrial bioenergetics and dynamics during germination of Arabidopsis thaliana seed

TitreReactivation of mitochondrial bioenergetics and dynamics during germination of Arabidopsis thaliana seed
Type de publicationCommunication
TypeCommunication sans actes dans un congrès
Date du colloque17-22/05/2015
Titre du colloqueInternational Congress on Plant Mitochondrial Biology
AuteurPaszkiewicz, Gaël , Macherel, David , Logan, David
Mots-clésGermination, Mitochondrial Dynamics, Seed
Résumé en anglais

Mitochondria are dynamic organelles in shoots and roots. Mitochondria move on F-actin using myosin motors, but movement can also result from remodelling of the actin cytoskeleton. This dynamism of mitochondria underpins their function and maintenance. For example, mitochondrial quality control underpins cell health and requires inter-mitochondrial fusion due to the uneven distribution of mtDNA within physically discrete mitochondria. Mitochondria are inactive in dry seed but must reactivate rapidly upon imbibition to provide ATP for germination. This reactivation requires not only a reactivation of mitochondrial metabolism but also of mitochondrial dynamics. Using a bioimaging approach we investigated reactivation using Arabidopsis as a model. Bioenergetic reactivation, visualised as the presence of a membrane potential, is almost immediate upon rehydration. However, reactivation of mitochondrial motility only occurs after transfer to optimal germination conditions. This late reactivation of mitochondrial motility appears specific: the actin cytoskeleton is present and dynamic early during imbibition as are other organelles that move in actin (e.g.ER). Reactivation of mitochondrial bioenergetics and dynamics is followed by dramatic reorganisation of the chondriome due to transient massive fusion, to form a perinuclear reticulum, followed by division. These data will be presented alongside results testing our hypothesis that the delay in activating mitochondrial motility is associated with the activation of mitochondrial quality control mechanisms to repair mtDNA damage incurred during maturation drying and imbibition.

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