Poster: Organelle Biogenesis
Abs #
1145: Investigating mitochondrial biogenesis using rice germination as a model system
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Presenter: |
Howell, Katharine A., kooks@cyllene.uwa.edu.au |
Authors | Howell, Katharine A. (A) Heazlewood, Joshua L. (A) Millar, A. Harvey (A) Whelan, James M. (A) | | Affiliations: |
(A): Biochemistry and Molecular Biology, School of Biomedical and Chemical Sciences, The University of Western Australia
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| Web Site: | http://millar3.biochem.uwa.edu.au/ | |
Mitochondria are present in dry seeds, but they have poorly formed cristae and a low density matrix, indicating that they are not fully functional. However, mitochondrial biogenesis occurs rapidly and early in the germination process and upon imbibition, the mitochondria develop cristae and the matrix density increases. This study examines the molecular mechanisms underlying the process of mitochondrial biogenesis using rice germination as a model system. Oxygen uptake, wet/dry weights and water content were determined for rice embryos at various stages of development. RNA was extracted from rice embryos 0 to 48 hours post-imbibition to generate cDNA, which was used to analyse transcript levels of numerous mitochondrial components (both nuclear and mitochondrial encoded) using real-time quantitative PCR. This analysis included subunits of electron transport chain complexes, cytochrome c, adenine nucleotide translocator, mitochondrial ribosomal proteins, alternative oxidase, uncoupling protein, import components and the mitochondrial division protein ADL2b. Nuclear to mitochondrial genome ratios were also determined using real-time quantitative PCR and transmission electron microscopy was performed to examine mitochondrial morphology. Developmental changes in mitochondrial protein levels were determined using Western blotting and immunodetection. This study not only examines the fundamental events involved in the initiation of mitochondrial function in the early stages of seedling growth but also provides an insight into the interaction between the nuclear and mitochondrial genomes.
