Induction mechanism of cytoplasmic male sterility by artificial chimera synthesis in Brassica.

摘要

We have studied graft transformation in tomato, aubergine, tobacco and soyabean, and gene transfer in chimaeral tissues in Brassica. In Brassicaceae, we obtained cytoplasmic male sterile (CMS) lines by artificial chimaera synthesis between red cabbage (Brassica oleracea var. capitata) and Komatsuna (B. campestris), and by intergeneric protoplast fusion between radish (Raphanus sativus) and cabbage (B. oleracea). Two types of different CMS lines stably maintain the radish CMS-specific orf138 and the surrounding structure in the mitochondria, although parental materials in both CMS lines are normal plants. RFLP and PCR analyses support the existence of stoichiometric shifts in mitochondrial (mt) and chloroplast (ct) genomes or genes. To make clear the stoichiometric shifts of cytoplasmic genomes accompanying CMS induction, RFLP patterns among mother plants and the resulting CMS lines were compared using known mt and ct gene probes. RFLPs in the 2 CMS lines were very similar to those in Ogura CMS radish ('Kosena' and 'MS Gensuke'). PCR cycle experiment, phylogenetic survey and sequencing data also support our postulate.