Abstract
dc:description.abstractPlants comprise most of the biosphere, are a dominating force in biogeochemical cycles, and serve as the ultimate source of almost all human food and energy. Plant development is a continuous cascade of dynamically self-organised regulatory programmes triggered by endogenous and environmental signals. The integrity of such regulation pivots on perpetual modulations of signalling, homeostasis, formation of biochemical patterns and mechanical stresses. Here, we advance the mechanistic insights across three areas of plant development: de novo vascular differentiation in the shoot apical meristem, regulation of cell polarity, and quantitative analysis of spatial gene expression. First, we deployed genetic, in vivo imaging and computational studies to derive an auxin-initiated feedback network of transcription factors regulating the vascular patterning and stem cell differentiation in the shoot apical meristem. Our functional studies showed that de novo vascular development is a semi-autonomous programme critical for auxin homeostasis and checkpoints of organ development, while spatiotemporal perturbations to the regulatory network affect stem cell maintenance and organismal dynamics. Next, to elucidate the regulatory mechanisms underlying auxin transport, we examined cell polarity within a generalised theoretical framework of reaction-diffusion networks at the single-cell scale. We identified the principles that regulate pattern stability and equilibria controlled by non-linear feedback, mass turnover and initial perturbations. Finally, we proposed a method of chromogenic in situ hybridisation that enables quantitative spatial inference of transcriptional activities. This universally applicable technique, validated for homeotic and cell cycle genes in the shoot apex, facilitates high-throughput analysis of gene expression heterogeneity in complex plant tissues across genotypes and growth conditions. Collectively, our results delineate new dimensions in the spatiotemporal gene regulation of plant development, in the underpinning multi-scale mathematical models, and in the applicable quantitative methods. This knowledge and the resources developed can propel a fundamental understanding of cross-talk in biological circuits towards practical applications in next-generation plant biotechnology and life sciences.
Degree
thesis:*- Name dc:type.qualificationname
- Doctor of Philosophy (PhD)
- Level dc:type.qualificationlevel
- Doctoral
- Grantor dc:publisher.institution
- University of Cambridge
- Year dc:date.issued
- 2024
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Gurzadyan, Aram
- Advisor dc:contributor.advisor
-
- Jonsson, Henrik
Subjects
dc:subject × 12Rights
dc:rightsIdentifiers
dc:identifier.*- Author Identifier
- 0000-0003-0618-9361
- OAI identifier oai:identifier
- oai:www.repository.cam.ac.uk:1810/385909