2026-09-23T07:48:32Zhttps://api.repository.cam.ac.uk/server/oai/request

oai:www.repository.cam.ac.uk:1810/3859092026-06-20T01:42:25Zcom_1810_205871com_1810_256064col_1810_206446

Spatiotemporal Interaction Networks in Plant Development https://doi.org/10.17863/CAM.119348 Gurzadyan, Aram 0000000306189361 Jonsson, Henrik Plants 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. University of Cambridge 2024-06-30 Thesis Doctoral Doctor of Philosophy (PhD) eng Gatsby Charitable Foundation https://www.repository.cam.ac.uk/handle/1810/385909 embargo 2030-06-23 https://www.repository.cam.ac.uk/bitstreams/d9279483-7465-47f5-9df0-637f6a0365cf/download 764dcc834488a46c22297d3452acea37 https://www.repository.cam.ac.uk/bitstreams/17596269-06e3-425d-aae6-972002258f14/download 87eda9de84448d1f82354d60eee3eb5f http://purl.org/NET/rdflicense/allrightsreserved Arabidopsis cell differentiation cell polarity computational biology computational modelling developmental biology developmental genetics dynamical systems gene regulatory networks hormonal signalling molecular genetics plant genetics