To produce highly asymmetric somatic hybrids, in order to transfer discrete traits between plant species, donor-chromosome elimination must be better understood. We examined the effects of radiation dose and time in culture on the elimination of donor genetic material. Mesophyll protoplasts of kanamycin-resistant donor Nicotiana plumbaginifolia were gamma-irradiated and fused with recipient mesophyll protoplasts of N. tabacum bearing the sulfur mutation (Su, phenotype yellow). Hybrid calli, selected on kanamycin-medium, were analyzed for N. plumbaginifolia genetic material by either dot-blot hybridization using a N. plumbaginifolia-specific repetitive DNA sequence probe, or by scoring the fraction of green hybrid calli (green = retained donor wild type allele). Both assays showed that the elimination of donor DNA increased with radiation dose, from 5 to 50 krad. At 50 krad, about one third of the hybrids lost 85% or more of the donor genome, which represents the retention of three, or fewer, donor chromosomes. In addition, donor DNA elimination continued for the first 12 months in culture. / Alternatively, BrdU (0.1 to 10 $\mu$M) followed by UV light was used to produce asymmetric hybrids. We demonstrated by dot-blot analysis or GUS expression, that both 10 $\mu$M BrdU with 5 min UV light treatment and 20-krad irradiation resulted in 50% donor DNA elimination. Furthermore, by combining gamma irradiation with BrdU/UV light treatment, we observed that donor DNA elimination in three month old calli exceeded that of the 50-krad treatment group at twelve months. However, in all above treatment groups, the extent of donor DNA elimination was highly variable. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 1854. / Major Professor: George W. Bates. / Thesis (Ph.D.)--The Florida State University, 1995.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77445 |
| Contributors | Trick, Harold N., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 112 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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