The roots of yield: coordination of shoot growth with soil environment

Plants are able to sense a large number of rhizospheric stimuli including the availability of nitrate and phosphate, soil volume and depth, and the presence of neighbouring plants. This information is then conveyed to the shoot system, where it can be used to regulate seed development and yield. However the mechanisms by which plants do this are generally poorly understood.

This project aims 1) to identify root-shoot signals that influence shoot growth, 2) to understand how these signals are regulated by rhizospheric conditions and 3) to understand how these signals are integrated to regulate reproductive development. We hypothesise that cytokinin is the key root-shoot signal controlling seed-set and yield in Arabidopsis. The project will use an interdisciplinary approach anchored by molecular genetics, and will use a combination of the model plant Arabidopsis and its close relative oilseed rape (Brassica napus), a major UK crop species. We will exploit the exceptionally well-developed molecular genetic and genomic resources of Arabidopsis to identify transcriptional changes that occur in response to rhizospheric stimuli. We will then test the role of the these signals on seed yield in Arabidopsis, using analysis of mutants, hypocotyl grafting and hormonal treatments. We will also use field and glasshouse experiments in oilseed rape, to test the role of root-shoot signals on seed yield in a crop species. Ultimately, better understanding of root-shoot signalling will help us optimise reproductive development in crop species, and therefore maximise yields.