University of Cambridge
47 Bateman Street
Cambridge CB2 1LR
Plants need to regulate developmental programs to adapt their body architecture to environmental requirements. Shoot branching is a remarkable example of such behaviour, as lateral buds can activate to generate new branches or remain dormant throughout the life cycle.
The decision to activate or not is based on the combination of endogenous and exogenous cues, and phytohormones have been shown to play a major role in integrating this variety of inputs in complex regulatory networks. For a bud to become active auxin produced at its apex has to be exported to the main stem. Consequently, buds compete for access to a shared auxin sink. The ease with which buds export auxin depends on their strength as an auxin source, the sink strength of the main stem and the dynamic properties of the auxin transport network. Growing branches can thus influence the ability of other buds to activate by modulating the sink strength of the shared auxin transport stream in the main stem. This framework generates a self-organising system that allows plants to control the number of synchronously active branches. Strigolactones have been shown to control the subcellular localisation of PIN proteins, ultimately altering the properties of the auxin transport network. As a result, perturbations in strigolactone biology lead to altered branching patterns.
The focus of my project is to clarify the mechanistic details of the auxin-strigolactone interaction during the regulation of axillary bud outgrowth. In particular, I am interested in understanding how strigolactone induces endocytosis of PIN proteins and what consequences this has for the properties of the auxin transport network.