The genetic basis of self-incompatibility in Campanula rapunculoides
LE3 .A278 2005
Bachelor of Science
The majority of Angiosperms exhibit some degree of self-incompatibility (SI). However, the genetic mechanism underlying SI has only been identified in a few plant families. Among these families, the basis for SI in understood in the Solanaceae and Rosaceae (gametophytic SI), and the Asteraceae and Brassicaceae (sporophytic SI) families. For those with gametophytic SI (GSI), a shared S-RNase based mechanism is reported in three plant families including the two mentioned above. The phylogenetic placement of Campanulaceae depicts it as more closely related to the Asteraceae, despite belonging in the same suborder as the Solanaceae. This therefore suggests that Campanulaceae could possess either type of SI. Thus, using the creeping bellflower, Campanula rapunculoides this project 1) assesses the type of SI response operating in the Campanulaceae. Next, 2) S-phenotypes are assigned based on the crosscompatibility category of the individuals from the breeding data. The segregation of these S-phenotypes is examined 3) using IEF gel electrophoresis and 4) 2-D gel electrophoresis. These verify the presence of polymorphic bands and present a series of potential S-loci. However, difficulty with the 2-D techniques prevented more definitive polymorphism from being identified. Finally, using the same IEF gel electrophoresis techniques, C. rapunculoides is determined not to have an SRNase based mechanism of SI as found in the Rosaceae. Thus, this study confirms that C. rapunculoides has a genetically based SI system and having ruled out the S-RNase mechanism lays open the need to investigate wider areas of its protein segregation.
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