CMS IN RYE - COMPARATIVE RFLP AND TRANSCRIPT ANALYSES OF MITOCHONDRIAFROM FERTILE AND MALE-STERILE PLANTS

The mitochondrial (mt) genomes of rye (Secale cereale L.) lines with ' 'normal'' and cytoplasmic male sterility (CMS) inducing ''Pampa'' cyto plasm were compared by detailed restriction fragment length polymorphi sm (RFLP) and Northern analyses. RFLP analyses using several heterolog ous mt genes as probes revealed considerable differences in the overal l structure of the two mt genomes. With cob and atpA, the data indicat e intragenic recombination and/or different copy numbers of these gene s in the two cytoplasms. In spite of this heterogeneity at DNA level, the transcriptional patterns of nine out of ten mitochondrial genes an alysed are unaffected. The exception is in the ''Pampa'' cytoplasm whi ch contains an additional cob-homologous transcript. Since this transc ript is strongly reduced in the presence of restorer genes, it might c ausally be correlated to the CMS phenotype.