title: Hyoscyamus muticus + Nicotiana tabacum fusion hybrids selected via auxotroph complementation.
abstract: Protoplasts of the nicotinamide-deficient Hyoscyamus muticus cell line nic(-) IVH2 and of the nitrate reductase-deficient Nicotiana tabacum cell line NR(-) cnx 68 were induced to fuse. Selection for putative interspecific hybrid clones was via auxotroph complementation. Controls included tests for cross-feeding, cross inhibition, PEG-induced variation, culture-induced variation, reversion, viability, delayed selection. Protrotrophic cell lines were recovered exclusively from PEG-treated mixtures of both protoplast types. The putative hybrid clones grew independent of exogenously supplied auxins and cytokinins, and at a faster rate than either parent. The morphogenic potential of different clones varied from 'non-morphogenic' to 'regeneration of fertile plants'. Indirect evidence for the hybrid nature of the clones is provided from a) tight selection, b) hormone-independent growth, c) hybrid vigour, d) extreme morphological variation, e) isoenzyme bands from both parents, f) morphogenic potential. Definite proof for the hybrid nature was, however, provided from species-specific DNA hybridization. Chimerism could be excluded since only the large subunit of Hyoscyamus muticus ribulose bisphosphate carboxylase was found and since species-specific DNA hybridization identified clones which gave no Nicotiana tabacum signal.
authors.affiliation: Friedrich Miescher-Institut, P.O. Box 2543, CH-4002, Basel, Switzerland.
authors.forename: I
authors.initials: I
authors.lastname: Potrykus
authors.forename: J
authors.initials: J
authors.lastname: Jia
authors.forename: G B
authors.initials: GB
authors.lastname: Lazar
authors.forename: M
authors.initials: M
authors.lastname: Saul