“Arabidobrassica”: Chromosomal recombination and morphogenesis in asymmetric intergeneric hybrid cells

A somatic hybrid cell line, cloned from an individual protoplast-fusion product between Arabidopsis thaliana and Brassica campestris, gave rise to formation of numerous plants differing drastically in morphology. Analysis of these various regenerants, all of which originated from one and the same heterokaryon derived from the fusion of two cells, shows the unspecific elimination of chromosomes of both parental species during the callus growth phase. Whereas the parental cells have so far not been sucessfully regenerated into plants, several of their different asymmetric hybrids are capable of morphogenesis. Furthermore, chromosomal analysis indicates extensive recombination. Most of the plants are predoinantly morphologically regular. Abnormalities are mostly limited to the flowers which tend to undergo phyllody. The results demonstrate that remote somatic hybridization may have applications although true amphidiploids may not be obtainable. The transfer of small units of genetic material between distantly related species by protoplast fusion seems to be a more realistic approach than the combination of complete, highly diverse genomes.