Genome wide analysis of auxin-cytokinin interaction

Plants are able to co-ordinate their growth and development throughout the plant body, so that root and shoot growth balance, and the vascular system carrying nutrients up and down between the root and shoot is maintained at an appropriate size for these growing systems. In addition, growth of the shoot system, root system and vascular system is balanced in accordance with environmental conditions, so that for example root growth is favoured over shoot growth when nutrients are limitting. This complex co-ordination of growth is acheived through the action of a network of growth-regulating hormones that move through the plant and interact to regulate growth. This project is aimed at understanding how two key players in this network, auxin and cytokinin, function together to acheive balanced growth across the plant body.

Plant hormones have a major role in regulating virtually all aspects of plant physiology. In recent years it has become apparent that plant hormones rarely act alone, but rather their signalling pathways are interlocked in complex networks. A prime example is in the interactions between auxin and cytokinins, which are classes of plant hormones that play a particularly important role in regulating plant development. Both hormones act as signals for cell division, cell elongation and cell differentiation in various developmental contexts and often regulate the same developmental process in a synergistic or antagonistic manner. Despite the obvious importance of the interactions between hormonal pathways, relatively little progress has been achieved in identifying the mechanisms or molecular components that mediate their cross-talk. Recent advances of our understanding of the molecular mechanisms of plant hormone action and new genome-wide tools make it possible to address this issue successfully. In this proposal we plan to elucidate the molecular mechanisms underlying auxin and cytokinin interaction in different developmental contexts, namely shoot branching, root branching and vascular morphogenesis. From our work so far we have generated number of tools and materials, which will be shared between the project partners and systematically tested in all studied processes; our groups have highly complementary specialist expertise in the core genomic and post-genomic technologies needed for the project which will be shared and further developed to achieve our objectives.