Date of Award
12-1-2025
Document Type
Dissertation
Degree Name
Ph.D. in Biological Science
First Advisor
Sarah Liljegren
Second Advisor
Yongjian Qiu
Third Advisor
Bradley Jones
School
University of Mississippi
Relational Format
dissertation/thesis
Abstract
The reproductive efficiency of flowering plants depends on proper formation of male and female reproductive tissues and their coordinated growth. In Arabidopsis thaliana, successful reproduction requires development of the gynoecium, formation of ovule primordia within the ovary, transfer of pollen grains released by the stamens to receptive stigmatic cells of gynoecium, and guided growth of pollen tubes containing the sperm nuclei to the ovules. Mutations that disrupt any of these processes, or the tissues involved in these events, result in reduced seed yield.
The objective of this thesis is to identify the contributions of two homeodomain transcription factors - SHOOT MERISTEMLESS (STM) and ARABIDOPSIS THALIANA HOMEOBOX 1 (ATH1), to the development of reproductive tissues in Arabidopsis thaliana. In addition to its fundamental role in maintaining the shoot apical meristem, the expression profile of STM is consistent with its proposed function in maintaining floral meristems, which give rise to the stamens and carpels, as well as the carpel margin meristem within the gynoecium, which produces key reproductive tissues including the ovule primordia and septum precursor cells. STM is known to heterodimerize with several BELL-type homeodomain partners, including ATH1, and that this interaction promotes expression of STM during axillary meristem formation.
However, due to the severe phenotype of the loss-of-function and intermediate alleles of STM which preclude formation of the gynoecium, analysis of the subsequent roles of STM in reproductive development and its potential interaction with ATH1 have been limited. Here, using the novel stm-12 and ath1-7 alleles, we present evidence that STM and ATH1 regulate maintenance of the floral meristem and carpel margin meristem, ensuring that carpels are produced to form the gynoecium, that the gynoecium is divided by a fused septum where the transmitting tract differentiates, and that a full set of ovule primordia are produced. Our results also suggest that STM and ATH1 are involved in coordinating growth of the stamens and gynoecium prior to pollination, and thereby support efficient fertilization of the ovules.
Recommended Citation
Shrestha, Anita, "Analysis of Roles of STM And ATH1 in Reproductive Development of Arabidopsis Thaliana" (2025). Electronic Theses and Dissertations. 3529.
https://egrove.olemiss.edu/etd/3529