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Mitochondrial biogenesis during seed germination of Arabidopsis thaliana is dependent on mitochondrial dynamics and mitophagy

Abstract : Mitochondrial dynamics underpin their function and maintenance. In dry seeds, all cellular processes are in stasis due to a low water content. Thus, the developmental switch leading to germination necessarily involves a reactivation of cellular dynamics. In order tobetter understand the role played by mitochondrial dynamics during germination we used Arabidopsis as a model for a bioimaging approach to investigate the rapid reactivation of mitochondria that is required in order to provide ATP to support germination. Bioenergetic reactivation, visualised as the presence of a mitochondrial membrane potential, is almost immediate upon rehydration. However, the reactivation of mitochondrial dynamics only occurs after several hours of rehydration. The reactivation of mitochondrialbioenergetics and dynamics lead to a dramatic reorganisation of the chondriome involving massive fusion and membrane biogenesis to form a perinuclear tubuloreticular structure enabling mixing of previously discrete mtDNA nucleoids. Mitophagy, an indicator of mitochondrial quality, is reactivated concomitant with a reactivation of mitochondrial dynamics, but is repressed at time of mitochondrial biogenesis. The end of germination coincides with fragmentation of the tubular chondriome leading to a doubling of mitochondrialnumber and heterogeneous redistribution of the nucleoids amongst the mitochondria, generating a population of mitochondria tailored to seedling growth. This thesis provides strong evidence for the tight interweaving of mitochondrial dynamics, mitochondrialbiogenesis and mitochondrial quality control that is required to ensure effective germination and the transition to autotrophy.
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https://tel.archives-ouvertes.fr/tel-01690721
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Submitted on : Tuesday, January 23, 2018 - 12:33:12 PM
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  • HAL Id : tel-01690721, version 1

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Gaël Paszkiewicz. Mitochondrial biogenesis during seed germination of Arabidopsis thaliana is dependent on mitochondrial dynamics and mitophagy. Agricultural sciences. Université d'Angers, 2017. English. ⟨NNT : 2017ANGE0010⟩. ⟨tel-01690721⟩

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