In Lactuca sativa, the dominant gene Tu confers resistance to infection by turnip mosaic virus (TuMV). Tu and Dm5/8, a gene for resistance to Bremia lactucae, are linked in L. sativa. The area surrounding Dm5/8 on the genetic map of L. sativa contains restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers. The orientation of Tu relative to Dm5/8 was not known. Locating Tu would indicate which markers are on the map of lettuce close to Tu. To locate Tu on the L. sativa genetic map, F$ sb3$ families from recombinant F$ sb2$ in the Dm5/8 area of a cross between TuMV-resistant (Cobbham Green) and susceptible (Calmar) cultivars were inoculated with TuMV and phenotyped for Tu by indirect enzyme-linked immunosorbent assay. Polyclonal antibodies for immunodetection were produced using turnip mosaic virus coat protein expressed in E. coli. Phenotypic ratios within F$ sb3$ families were used to determine individual F$ sb2$ genotypes for Tu. With these genotypes, Tu was located on the genetic map of L. sativa relative to data present for Dm5/8 and surrounding markers, between OPM18 and OPY13. Using bulked segregant analysis, bulks created for the Dm5/8 locus were screened for genetic polymorphisms by the RAPD technique. Five new RAPD markers, UBC346, UBC517, UBC563, UBC599, and UBC675 were found linked to Tu after mapping relative to F$ sb2$ genotypes for Tu and other RAPD markers. The resulting three-point mapping information indicates that Tu is flanked by two markers, OPM18/OPL08 and UBC346, at respective genetic distances of 0.4 and 0.7 cM.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.69684 |
| Date | January 1993 |
| Creators | Robbins, Marjorie |
| Contributors | Fortin, Marc (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Plant Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001382960, proquestno: AAIMM91782, Theses scanned by UMI/ProQuest. |
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