Publication Date
2015
Document Type
Dissertation/Thesis
First Advisor
Sims, Thomas L.
Degree Name
Ph.D. (Doctor of Philosophy)
Legacy Department
Department of Biological Sciences
LCSH
Molecular biology; Plant sciences; Genetics; Plants--Self-incompatibility; Plants--Reproduction; Pollination; Plants--Pollination
Abstract
My dissertation is based on studies of Gametophytic Self-Incompatibility (GSI), a system that allows plants to reject "self" pollen while accepting "non-self" pollen, thus preventing inbreeding and promoting genetic diversity in populations. In GSI, pollen grains deposited on the stigma of the floral pistil germinate and begin to grow through the transmitting tract tissue of the style. As the pollen tubes grow through the transmitting tract, they import recognition variants of a secreted protein known as the S-locus ribonuclease (S-RNase). If there is a match of recognition specificity between the pollen tube and the imported S-RNase, the S-RNase will degrade pollen-tube RNA, inhibiting protein synthesis & pollen tube growth. Conversely, if there is no match between pollen tube and S-RNase, the action of the S-RNase is inhibited, and the pollen tube continues to grow normally to the ovary. Inside pollen tubes, non-self S-RNases are recognized by the SCF SLF complex comprising multiple variants of the pollen-recognition protein named SLF, along with three other proteins: SSK1, SBP1 and Cullin-1. I have been using protein-interaction assays (BiFC assays) based on the reconstitution of a fluorescent protein, to study interactions between components of the SCFSLF complex and S-RNase. Previous studies revealed that multiple SLF genes collaborate during non-self S-RNase recognition. Based on my data, SLF10 and to a lesser extent, SLF1, SLF3, SLF4 and SLF5 showed interaction with different S-RNase constructs. In addition, data in my study suggests that a "bridge" protein may be needed to stabilize proteins interactions between SLF and S-RNase. The work that has been completed will lead to a better understanding of self versus non-self recognition in pollination. An understanding of GSI mechanisms should also lead to the ability to manipulate breeding barriers in agricultural crops such as tomatoes, potatoes and fruit trees.
Recommended Citation
Qi, Qinzhou, "Protein function and interactions in gametophytic self-incompatibility : collaborative recognition of S-RNase in vivo" (2015). Graduate Research Theses & Dissertations. 4567.
https://huskiecommons.lib.niu.edu/allgraduate-thesesdissertations/4567
Extent
183 pages
Language
eng
Publisher
Northern Illinois University
Rights Statement
In Copyright
Rights Statement 2
NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.
Media Type
Text
Comments
Advisors: Thomas L. Sims.||Committee members: Barrie Bode; Melvin Duvall; Gabriel Holbrook; Timothy Robbins.