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Dissertation
THE ROLES OF AHLS IN LIGHT-MEDIATED GROWTH IN ARABIDOPSIS
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004413
Handle:
https://hdl.handle.net/2376/119046
Abstract
Transcriptional regulation of developmental processes is particularly important for plants, which are sessile organisms. The pathways that are involved in these processes can be studied using growth media plates. The use of growth media plates has several advantages over soil-grown plants, such as reproducibility, ease of use, and affordability. When the production location of Phytagel (Sigma) moved, the subtle phenotypes of key mutants involved in light-mediated growth were not reproducible. Since the original formula was discontinued, a new gelling agent, Gellan, was tested and found to be a suitable replacement. One of the non-reproducible phenotypes affected by the new Phytagel formula is conferred by null allele combinations in the AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) family. The AHLs are a family of transcription factors involved in regulating growth and development in the model plant Arabidopsis thaliana (Arabidopsis). One member of the AHL family, AHL29/SUPRESSOR OF PHYB4 #3 (SOB3), has been shown to regulate light-mediated growth and development of the hypocotyl in Arabidopsis. Until now, the majority of studies on SOB3 have been in continuous light or long day growing conditions. Therefore, Arabidopsis was used to study how SOB3 regulates hypocotyl elongation throughout short days (SD). SOB3 inhibits hypocotyl growth in SD, which is consistent with its effects in constant light. The RNA-seq data indicates that PHYTOCHROME INTERACTING FACTORS (PIFs) 4, 5, 7, and 8 along with PIF-target genes are repressed by AHLs. Several of the repressed PIF target genes identified have not been previously described as AHL-regulated, including PRE1, PIL1, HFR1, CDF5, and XTR7. Genes involved in hormone signaling have also been found to be AHL-repressed, such as members of gibberellic acid-stimulating Arabidopsis (GASA) family, GAS4 and GASA14. The RNA-seq data also suggests that AHLs activate the expression of growth repressors to control hypocotyl elongation, such as HY5 and IAA17. While different genes were regulated by SOB3 at different time points in SD, ChIP-seq data suggests that SOB3 binds to similar genes throughout the day. This indicates that SOB3 is likely interacting with other AHLs or other proteins to control the expression of these target genes.
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Details
- Title
- THE ROLES OF AHLS IN LIGHT-MEDIATED GROWTH IN ARABIDOPSIS
- Creators
- Caitlin Jacques
- Contributors
- Michael Neff (Advisor)Andrei Smertenko (Committee Member)Kiwamu Tanaka (Committee Member)Stephen Ficklin (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 261
- Identifiers
- 99900883238601842
- Language
- English
- Resource Type
- Dissertation