Molecular characterization of mitochondrial DNA of different subtypes of male-sterile cytoplasms of the sugar beet Beta vulgaris L

Mitochondrial (mt) DNA from eight cytoplasmic male-sterile (cms) lines of sugar beet from different breeding stations was investigated by restriction fragment analysis and Southern hybridization. All cms lines showed similar but not identical restriction and hybridization signal patterns, readily distinguishable from those of fertile (N) cytoplasm. Digestion of the mtDNA with BamHI, EcoRI, SalI, and XhoI revealed distinct differences between the sterile lines, and six subtypes of the S cytoplasm could be distinguished. Differences between the sterile lines were confirmed by hybridization with a \(\overline{\overline {COX}} II\) gene probe revealing minor, line-specific hybridization signals. The data presented provide evidence for the existence of considerable variation within the only commercially used source of cms in the sugar beet, the Owen's type of cytoplasm.