Date of this Version
Strehle, Mackenzie. Characterization of a Novel Mitochondrial Plasmid in Brassica. University of Nebraska-Lincoln. 2018.
Possessing some of the largest and most complex genomes of any eukaryotic organelles, plant mitochondria are notorious for their rapidly rearranging genetic framework. In addition to containing a large and complex mitochondrial genome, the mitochondria of several plants in the genus Brassica have also been shown to contain an independent, self-replicating linear plasmid. Interestingly, the plasmid appears to be able to move independently between the cytoplasm and the mitochondria, and it can be paternally inherited, unlike the rest of the mitochondrial genome. The plasmid also has features similar to those of adenoviruses, including terminal inverted repeats and covalently bound proteins at its 5’ termini. This has led us to hypothesize that the plasmid was originally acquired as a virus by a subspecies of Brassica and has since become a stable component of the mitochondrial machinery in these plants. If we can determine how the Brassica plasmid moves between the cytoplasm and mitochondria, it has the potential to be used as a vector to target individual gene sequences into plant mitochondria and direct the synthesis of specific RNA molecules and proteins within the organelle. A mitochondrial-targeting plasmid such as this would not only allow for a better understanding of the molecular composition of plant mitochondria, but it may also lead to an enhanced ability to alter their genetic and biochemical environment, which could have effects on the traits and life history of the plant.