Reorganization of Mitochondrial Genomes of Cms-S Maize Associated With Reversion to Fertility and Changes in Nuclear Background (S1 - S2 Plasmids, Cytochrome Oxidase I and Ii, Apocytochrome B)

256 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.The cms-S type of cytoplasmic male sterility in maize is characterized by the presence of linear mitochondrial plasmid-like DNAs, S1 and S2. Sequences homologous to S1 and S2 are also found in the main mitochondrial genomes of cms-S and normal fertile lines of corn.Spontaneous reversions to fertility in three cms-S inbred lines of corn, M825, 38-11, and WF9, as well as in the hybrid M825 x Oh07, are accompanied by reorganizations in the mitochondrial genome. The pattern of mitochondrial genome rearrangements in the revertants is largely dependent on the nuclear background. These rearrangements involve S1, S2, and cytochrome oxidase subunit I (COI) gene sequences, but generally not apocytochrome B (COB) and cytochrome oxidase subunit II (COII) gene sequences.Rearrangements in the mitochondrial genome are not exclusive to the reversion event. Change in the nuclear genomic background also causes mitochondrial DNA reorganization.The nature and consequences of these rearrangements on the phenomenon of cytoplasmic male sterility and on mitochondrial DNA replication are discussed.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD