Identification and expression of the kosena radish (Raphanus sativus cv. Kosena) homologue of the ogura radish CMS-associated gene, orf138

A CMS-associated gene, orf125, present in the Japanese radish cultivar Kosena, has a sequence homologous to that of the ogura CMS-associated gene, orf138, except for two amino acid substitutions and a 39 bp deletion in the orf138 coding region. In Kosena radish, orf125 is linked with orfB, whereas the orf125 locus differs in a Brassica napus CMS cybrid derived from protoplast fusion between Kosena radish and B. napus. A novel mtDNA sequence is present in the 3′-flanking region of orf125 in the B. napus kosena CMS cybrid. The orf125 is expressed both in the radish and the B. napus kosena CMS cybrid. Its accumulation is strongly associated with the CMS phenotype in B. napus. Fertility restoration was accompanied by a decrease in the amount of ORF125 in B. napus.