Farnesylation-mediated control of skotomorphogenesis and seedling establishment in Arabidopsis thaliana

Hickerson, Neil Murray

Farnesylation-mediated control of skotomorphogenesis and seedling establishment in Arabidopsis thaliana

dc.contributor.advisor	Samuel, Marcus
dc.contributor.author	Hickerson, Neil Murray
dc.contributor.committeemember	Muench, Douglas
dc.contributor.committeemember	Chua, Gordon
dc.contributor.committeemember	Arcellana-Panlilio, Mayi
dc.contributor.committeemember	Belmonte, Mark
dc.date	2024-11
dc.date.accessioned	2024-05-22T19:49:18Z
dc.date.available	2024-05-22T19:49:18Z
dc.date.issued	2024-05-21
dc.description.abstract	Skotomorphogenesis is growth in the dark, a critical process in the establishment of seedlings for all crop systems in which the seed is sown below the soil surface. Regulation of skotomorphogenesis, seedling growth, plant development, and stress tolerance has been shown to involve the interplay and negative interactions between the signalling and synthesis of the stress hormone abscisic acid (ABA) and the growth hormone brassinosteroid (BR). Mutations or modifications resulting in reduced BR synthesis have been shown to enhance perception of ABA for improved stress responses and overall drought tolerance. A previous study demonstrated that the farnesyltransferase, Enhanced Response to ABA 1 (ERA1), is required for BR synthesis through farnesylation of the terminal enzyme of the BR biosynthesis pathway. However, new evidence suggests that the absence of ERA1 can directly impact the BR-dependent skotomorphogenic response as farnesylation may be important in the activity of downstream genes associated with BR-induced signalling. Screening BR-regulated gene expression for potential substrates for farnesylation has yielded three likely candidate proteins: a bHLH-type transcription factor of the Phytochrome-Interacting Factor (PIF) group, PIF3; and a pair of cell-wall modification enzymes of the Xyloglucan endotransglycosylase/hydrolase (XTH) family, XTH22 and XTH23. Complementation experiments revealed that PIF3 lacking farnesylation was unable to rescue the skotomorphogenic defects observed in the multigenic pifq mutant background. PIF3 farnesylation was further shown to be required for transcriptional activity of PIF3 in the transgenic seedling. This study has directly linked PIF3 farnesylation with transcriptional control during skotomorphogenesis. Additional experiments highlighted the complexity of farnesylation-mediated regulation among downstream effectors. Methods and tools developed in this study can be used to verify additional targets responsible for the impact of farnesylation on seedling growth.
dc.identifier.citation	Hickerson, N. M. (2024). Farnesylation-mediated control of skotomorphogenesis and seedling establishment in Arabidopsis thaliana (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/118816
dc.language.iso	en
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Farnesylation
dc.subject	Skotomorphogenesis
dc.subject	Brassinosteroid
dc.subject	Seedling Establishment
dc.subject	CRISPR-Cas9
dc.subject	Plant Developmental Biology
dc.subject.classification	Botany
dc.title	Farnesylation-mediated control of skotomorphogenesis and seedling establishment in Arabidopsis thaliana
dc.type	doctoral thesis
thesis.degree.discipline	Biological Sciences
thesis.degree.grantor	University of Calgary
thesis.degree.name	Doctor of Philosophy (PhD)
ucalgary.thesis.accesssetbystudent	I require a thesis withhold – I need to delay the release of my thesis due to a patent application, and other reasons outlined in the link above. I have/will need to submit a thesis withhold application.