Structural and Transcriptional Variation of Mitochondrial DNA in Pollen-Sterile Agamospermous Sugar Beet (Beta vulgaris L.) Progeny

The cytoplasm status according to mitochondrial sequence tags was determined in agamospermous sugar beet progenies characterized by unstable manifestation of cytoplasmic male sterility. The detected variations in the ratios of homologous sequences related to the N and S mtDNA types did not correlate with pollen phenotypes of the plants. Polymerase chain reaction allowed semiquantitative evaluation of these variations and their detection. A cDNA corresponding to a hitherto unknown minor RNA and containing a consensus sequence of dicotyledonous plant promoters was detected by mtRNA display. Probable sources of CMS variability in agamospermous sugar beet progenies are discussed.