A Network Approach to Identify Key Regulators of Fruit Development in Fragaria vesca, a Diploid Strawberry

Shahan, Rachel

A Network Approach to Identify Key Regulators of Fruit Development in Fragaria vesca, a Diploid Strawberry

dc.contributor.advisor	Liu, Zhongchi	en_US
dc.contributor.author	Shahan, Rachel	en_US
dc.contributor.department	Cell Biology & Molecular Genetics	en_US
dc.contributor.publisher	Digital Repository at the University of Maryland	en_US
dc.contributor.publisher	University of Maryland (College Park, Md.)	en_US
dc.date.accessioned	2018-07-11T05:30:23Z
dc.date.available	2018-07-11T05:30:23Z
dc.date.issued	2018	en_US
dc.description.abstract	Post-embryonic organogenesis is a feature unique to plants, an example of which is flower and fruit production. Previous work on strawberry fruit development has focused primarily on the latter stages, including ripening. Comparatively little is known about the molecular events underpinning fruit set, the pivotal stage at which fruit development proceeds or terminates. This thesis investigates early fruit development using Fragaria vesca, a diploid strawberry, as a model. In collaboration with a bioinformatician, I generated gene co-expression networks from 92 previously generated RNA-Seq libraries profiling multiple tissues and stages of strawberry flower and fruit development. I demonstrate the utility of co-expression networks in illuminating molecular processes underlying fruit development. Experimental validation of the networks includes demonstration of increased iron transport soon after fertilization and identification of FveUFO1 as an important regulator of floral meristem determinacy and floral organ identity. Using the co-expression networks, I discovered the surprising expression of FvFT1, a homolog of FLOWERING LOCUS T (FT), in the fleshy fruit immediately post-fertilization. In many plant species, the FT peptide is a non-cell autonomous signal that initiates flowering in response to inductive photoperiod. I found that FvFT1 expression is responsive to temperature, but not photoperiod, in strawberry fruit. Further, transcriptional activation is detectable in the vascular bundles connecting the fruit to the seeds, raising the possibility that FvFT1 may facilitate cross-tissue communication. Signal from an FvFT1-GFP translational fusion protein is visible in seed nuclei despite its localized transcription in the vasculature. However, analysis of FvFT1 RNAi plants failed to identify a fruit phenotype, possibly due to redundancy among three FvFT paralogs. Finally, to develop additional research tools for F. vesca, I isolated and tested fruit tissue-specific promoters based on genes identified with differential expression analyses. These analyses revealed genes strongly expressed in the receptacle fruit, thereby identifying potential regulators of early fruit development and attractive candidates for future study. Together, this work advances the systems-level infrastructure for studying molecular regulation of F. vesca fruit development, points to a novel role for FT distinct from its known function in floral initiation, and provides molecular tools useful to the F. vesca community.	en_US
dc.identifier	https://doi.org/10.13016/M2H12VB3P
dc.identifier.uri	http://hdl.handle.net/1903/20714
dc.language.iso	en	en_US
dc.subject.pqcontrolled	Developmental biology	en_US
dc.subject.pqcontrolled	Genetics	en_US
dc.subject.pqcontrolled	Molecular biology	en_US
dc.subject.pquncontrolled	Co-expression networks	en_US
dc.subject.pquncontrolled	Flowering Locus T	en_US
dc.subject.pquncontrolled	Fruit development	en_US
dc.subject.pquncontrolled	Strawberry	en_US
dc.subject.pquncontrolled	Transcriptomics	en_US
dc.title	A Network Approach to Identify Key Regulators of Fruit Development in Fragaria vesca, a Diploid Strawberry	en_US
dc.type	Dissertation	en_US