The aim of the work described in this thesis was to investigate the expression of mitochondrial, chloroplast and nuclear genes in successive sections along the length of the 7 day-old light-grown wheat leaf (Triticum aestivum). The wheat leaf represents a spatial separation of a temporal sequence of development, from basal meristematic to mature, photosynthetically competent cells. This sequence of cellular development is paralleled by a functional differentiation in which the energy requirement of the cell changes from an initial dependence upon oxidative phosphorylation to a combined and diumally modulated dependence on oxidative and photophosphoryla-tion. It was found that the abundance of specific mitochondrial genes (coxl, coxll, cob and atpA) per cell decreased between 3 and 10 fold within the basal lcm of the leaf and then remained at an approximately constant level to the distal tip. The abundance of specific mitochondrial RNA transcripts (coxl, coxll cob and AtpA) also decreased in relative abundance per cell beyond the basal lcm of the leaf, but in a manner which was not directly related to the decrease in mitochondrial gene copy number. Evidence was also found for the differential expression of nuclear gene(s) encoding the mitochondrial adenine nucleotide translocator. The relative abundance of specific mitochondrial proteins (the a-subunit of the Fi ATPase, subunit II of the cytochrome c oxidase complex, malate dehydrogenase and the adenine nucleotide translocator) per cell was found to remain approximately constant in the region to 4cm from the meristem. However the mitochondrial glycine decarboxylase protein was found to increase in relative abundance per cell in this region of the leaf. The abundance of specific chloroplast (rbcL and psbA) and nuclear (rbcS and cab) gene transcripts encoding chloroplast proteins were found to increase per cell along the length of the leaf from initially low levels in the meristematic region. These preliminary results illustrate the differential expression of nuclear and organelle genomes during cellular differentiation and indicate the complexity of the coordinated interactions required to satisfy the changing energy requirement of the plant cell.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662999 |
| Date | January 1987 |
| Creators | Topping, Jennifer Foster |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14556 |
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