On Gene Regulatory Networks Controlling Flowering Time in Brassica napus

Sidhu, Gurpinder Singh (2025) On Gene Regulatory Networks Controlling Flowering Time in Brassica napus. Doctoral thesis, University of East Anglia.

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Abstract

Flowering plants respond to multiple environmental and endogenous cues to correctly time the crucial transition from the vegetative to floral state. Most of our knowledge of the gene regulatory network (GRN) controlling flowering time has been derived from the model plant, Arabidopsis thaliana. This knowledge needs to be translated to crop plants to support the development of varieties that can be grown in different and rapidly changing climatic conditions. With the dual challenges of more complex genomes and limited prior knowledge in crops, however, this translation is not always straightforward. In this thesis, I present a study of the GRN controlling flowering time in Brassica napus (Oilseed rape), an allotetraploid crop that is a close relative of Arabidopsis. Using a comparative transcriptomics approach, I show that the majority of the orthologous gene pairs have similar expression dynamics over plant development between Arabidopsis and Brassica napus. However, flowering time genes exhibit a significantly higher rate of divergence in expression patterns from their Arabidopsis orthologues. Despite these divergences, the inferred GRN consisting of these genes exhibits a similar network topology to the network known in Arabidopsis. This is likely due to preferential retention of these genes in higher paralogue numbers, which allows subtle changes in the regulation of individual paralogues, while still conserving the overall regulatory structure through evolutionary time. I discover and present a detailed analysis of one such example where the orthologues of gene, SOC1, have similar expression patterns under normal conditions, but have diverged expression patterns under cold temperature conditions, suggesting divergence in regulation among paralogues in response to the temperature change. Altogether, this thesis expands our understanding of the environmental and genetic control of flowering time in Brassica napus and provides a study of regulatory divergences among paralogous genes in a polyploid system.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	16 Feb 2026 11:23
Last Modified:	16 Feb 2026 11:23
URI:	https://ueaeprints.uea.ac.uk/id/eprint/101942
DOI:

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