Asymmetric somatic hybridization between tall fescue (Festuca arundinacea Schreb.) and irradiated Italian ryegrass (Lolium multiflorum Lam.) protoplasts

• Published in: Theoretical and applied genetics Vol. 88; no. 5; p. 509
• Main Authors: Spangenberg, G, Valles, M.P, Wang, Z.Y, Montavon, P, Nagel, J, Potrykus, I. (Swiss Federal Inst. of Technology, Zuerich (Switzerland). Inst. for Plant Sciences)
• Format: Journal Article
• Language: English
• Published: Germany 01.07.1994
• Subjects: CITOPLASMA; CYTOPLASME; FESTUCA ARUNDINACEA; FUSION DE PROTOPLASTES; FUSION DEL PROTOPLASTO; HIBRIDOS SOMATICOS; HYBRIDE SOMATIQUE; LOLIUM MULTIFLORUM; NOYAU CELLULAIRE; NUCLEO
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/bf01240911

Intergeneric asymmetric somatic hybrids have been obtained by the fusion of metabolically inactivated protoplasts from embryogenic suspension cultures of Festuca arundinacea (recipient) and protoplasts from a non-morphogenic cell suspension of Lolium multiflorum (donor) irradiated with 10, 25, 50, 100, 250 and 500 Gy of X-rays. Regenerating calli led to the recovery of genotypically and phenotypically different asymmetric somatic hybrid Festulolium plants. The genome composition of the asymmetric somatic hybrid clones was characterized by quantitative dot-blot hybridizations using dispersed repetitive DNA sequences specific to tall fescue and Italian ryegrass. Data from dot-blot hybridizations using two cloned Italian ryegrass-specific sequences as probes showed that irradiation favoured a unidirectional elimination of most or part of the donor chromosomes in asymmetric somatic hybrid clones obtained from fusion experiments using donor protoplasts irradiated at doses below/equal 250 Gy. Irradiation of cells of the donor parent with 500 Gy prior to protoplast fusion produced highly asymmetric nuclear hybrids with over 80% elimination of the donor genome as well as clones showing a complete loss of donor chromosomes. Further information on the degree of asymmetry in regenerated hybrid plants was obtained from chromosomal analysis including in situ hybridizations with L. multiflorum-specific repetitive sequences. A Southern blot hybridization analysis using one chloroplast and 6 mitochondrial-specific probes revealed preferentially recipient-type organelles in asymmetric somatic hybrid clones obtained from fusion experiments with donor protoplasts irradiated with doses higher than 100 Gy.