Shedge, Vikas , Arrieta-Montiel, Maria , Xu, Ying-Zhi , Sandu, Ajay Singh , Mohammed, Saleem , Mackenzie, Sally .
Physiological influence of plant mitochondrial genome instability.
The plant mitochondrial genome is distinguished by its propensity to incorporate foreign DNA sequences and to undergo both homologous and illegitimate recombination. The evolutionary implications of this unusual activity for plant adaptation are not understood, but these features are not shared with animal mitochondrial genomes. To date, most studies of mitochondrial genome changes in higher plants have relied on materials emerging from cell suspension cultures, wide hybridizations or naturally occurring reversions to fertility of cytoplasmic male sterile mutants. All of these instances are, by their nature, subject to early selection, generally precluding the study of mitochondrial genomic changes as they influence cellular functions. We are studying three nuclear genes that participate in mitochondrial recombination surveillance. The disruption of any one of these loci results in reproducible rearrangement of the plant mitochondrial genome that can be accompanied by cytoplasmic male sterility. Simultaneous mutation at two of these loci displays an even more profound effect on mitochondrial genome stability accompanied by dramatic changes in plant growth rate and morphology. This type of genetic approach offers a powerful and novel strategy to investigate the influence of mitochondrial genome organization on cellular and physiological functions of the plant. We have utilized microarray analysis, redox and biochemical studies together with cross-species analysis by RNAi-mediated gene suppression to investigate the influence of mitochondrial genome stability on plant growth. While particular changes to the mitochondrial genome show an association with pollen sterility, the more profound changes result in reduced ATP levels, altered redox status of the cell, dramatic reductions in cell division rates, and enhanced susceptibility to programmed cell death. Our observations to date suggest that changes in mitochondrial genome status can provide both adaptive and deleterious consequences to the plant even while plant mitochondrial gene expression appears to remain essentially unaltered.
Log in to add this item to your schedule
1 - University of Nebraska, Lincoln, NE 68588, N305 Beadle Center for Genetics Research
2 - University of Nebraska, N305 Beadle Center for Genetics Research
3 - University of Nebraska, N305 Beadle Center for Genetics Research, Lincoln, NE, 68588-0660, USA
male sterile mutant
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM