The Brassica mitochondrial plasmid can be sexually transmitted. Pollen transfer of a cytoplasmic genetic element

The 11.3 kb mitochondrial (mt) plasmid was restored to rapeseed (Brassica napus) plants cured of the plasmid (by in vitro culture) by crossing to plasmid-containing males, but not by grafting plasmidless shoots onto plants containing the plasmid. Plasmid restoration is not associated with alterations in mt DNA restriction patterns nor is it likely the result of excision of plasmid sequences from the mt genome. Restoration of the mitochondrially-associated plasmid is probably the result of transmission of cytoplasm from the male parent through the pollen to the egg cell in the female. Pollen transfer of the plasmid also occurred in other crosses regardless of cytoplasmic or nuclear background and at an average rate of 50%. These experiments demonstrate that a cytoplasmic genetic element can be non-maternally inherited in Brassica and suggest that the mitochondria with which this element is associated are transmitted to the egg cell during fertilization. © 1989 Springer-Verlag.