title: Alteration of mitochondrial genomes containing atpA genes in the sexual progeny of cybrids between Raphanus sativus cms line and Brassica napus cv. Westar.
abstract: We have investigated the fate of the mitochondrial genomes of cybrids derived from "donor-recipient" protoplast fusion between X-irradiated Raphanus sativus (cms line) and iodoacetamide-treated Brassica napus cv. Westar. Two out of ten fusion products were male-sterile with the diploid chromosome number of B. napus. The mitochondrial (mt) genomes of the cybrids and their progeny were further analyzed by DNA-DNA hybridizaion using the pea mitochondrial ATPase subunit gene (atpA) as a probe. One cybrid, 18-3, had a 3.0 kb fragment characteristic of B. napus and a 2.0 kb non-parental fragment when the BamHI-digested DNA was hybridized with the probe. In the first-backcrossed progeny of this cybrid, the hybridization pattern was not stably inherited. A 4.0 kb radish fragment, not detectable in the cybrid, appeared in one of the BC1 generation siblings, and the 2.0 kb non-parental fragment was lost in another. The hybridization patterns in BC1 progeny siblings of cybrid 12-9 were also varied. The alteration of mtDNA in the cybrid progeny continued to the BC2 generation. There was no clear evidence of a heteroplasmic state or of sub-stoichiometric molecules in the mt genome of cybrid 18-3. A possible cause of the observed alteration in the mt genome is discussed.
authors.affiliation: Plantech Research Institute, 1000 Kamoshida, Midori-Ku, 227, Yokohama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: J
authors.initials: J
authors.lastname: Imamura