Publication Date


Document Type


First Advisor

Bode, Barrie P.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences


Molecular biology; Genetics; Plants


Gametophytic Self-incompatibility is the biochemical process in which plants can recognize their own (self) pollen, therefore rejecting it while accepting pollen of another plant (non-self) of the same species. This mechanism is governed by two genes that encode for pollen-recognition (pollen-S) and style-recognition (pistil-S) components which are more commonly known as SLF and S-RNase respectively. These genes are closely linked on the large, multiallelic S-locus and are, therefore, considered haplotypes of each other. When one of the SLF variants expressed in the haploid pollen matches the haplotype of the S-RNase in the diploid pistil tissue, rejection occurs through SR-Nase activity. If there is no match between the two haplotypes, SR-Nase is ubiquinated and the pollen can grow and fertilization occurs. In this research, SLF and S-RNase found in Petunia axillaris were studied to help gain an understanding in this process. One place to start is gathering more information on the S-Locus, since these genes are known to all be located there. It is estimated that the S-Locus, which is at least 8 MB in length, is known to house at least 118 genes. Although the organization of the S-locus is unique in that it is suppressed for recombination the entire S-locus has never been cloned or assembled. By establishing gene content, gene order, and linkage of the S-locus of P. axillaris, comparisons can be made between this self-compatible plant and self-incompatible plants of other species in the Solanaceae. This will aid in a better understanding of all the underlying mechanisms of GSI and will help in finding out how all the genes and their proteins involved in self-incompatibility interact at a molecular level. A combination of having the published genome for Petunia axillaris, together with a 5X BAC library for the sequenced line gives us the resources to assemble an entire S-locus for the first time. In this research, use of BAC library screening has determined that four different BAC clones house multiple SLF genes that show up on different scaffolds on the published genome. These results show that the scaffolds that house the SLF genes are near each other. In the future, these results can be used along with BAC-end sequencing and sequence alignment to the current P. axillaris genome to assemble a complete S-locus.


Advisors: Barrie Bode.||Committee members: Mel Duvall; Mitrick Johns.||Includes bibliographical references.||Includes illustrations.


ix, 63 pages




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