The proposal (RETRICELL) has an overarching objective: to create viable industrially useful novel cells and intact plants with profound changes in their molecular and biosynthetic machineries. This objective will be underpinned by in depth fundamental mechanistic investigations to understand and resolve critical bottlenecks hindering the full application of synthetic biology to plants. The starting point of RETRICELL is preliminary results which have already created a partially retrofitted rice cell which will permit the conservation of substantial amounts of carbon and energy and their diversion towards target pathways without compromising the viability of the cell and resulting plants. At the fundamental science level the program will substantially rewire core metabolism and deregulate key precursor formation, finally reconstituting an industrially useful heterologous pathway as proof of concept. Dedifferentiated rice cells and plants, will permit RETRICELL to address the fundamental biological questions necessary to establish the basis for moving to application. This is an ambitious proposal, however, entirely realistic based on preliminary results and the ability of the group to undertake complex metabolic engineering programs in cereals. The proposed program is higher risk but high benefit, and if successful either fully or in part will result in major breakthroughs which will help to advance the science in a number of different important related areas. These are discussed in detail in the main body of the proposal. Our approach offers a unique opportunity for novel and innovative approaches to relieve the current bottlenecks which thus far have hindered the application of synthetic biology to unlocking the plant’s tremendous potential as a useful factory for the exploitation of its chemodiversity for industrial applications. The proposal is if high industrial relevance on two grounds. Firstly the technologies to be developed in the course of the project and concomitant Intellectual Property are of high relevance not only in the plant field but also in microbes. Secondly the target proof of concept nutritionaly important phytosterols are of high interest to the neutraceutical and pharmaceutical industries and we will leverage this interest to attract further commercial involvement in the project.