In an era characterized by dramatic shrinking of fossil energy sources, plants, representing natural power stations, become more and more indispensable to support and maintain the well-being of our current human world population.
Curiously enough, our present understanding of how plants develop and growth is still very limited and this shortage becomes exemplary when the subterranean part of the plant is considered. Roots however serve a multitude of functions that are essential for a normal growth and development of the plant. Within this network, 5 Belgian Laboratories assisted by an eminent European partner will combine efforts to tackle major aspects of root growth and development in a well-focused strategy by concentrating one species, Arabidopsis thaliana that turned out to be an ideal model system for root developmental research. The anticipated new insights will certainly become essential for all future approaches to enhance growth of plants as alternative energy sources.

The project aims at answering the following questions:

- Which molecular mechanisms control cell division and cell elongation activity in roots? What are the key regulators of these processes? Is endoreduplication an essential factor for cell elongation? What is the involvement of H-ATPase and aquaporins? Which role can be allocated to cell wall composition, cytoskeleton architecture and vacuole genesis in the cell elongation process? (P1, P4, P5)

- Which molecular events control the initiation of lateral roots and the subsequent determination of root architecture? Lateral root initiation depends on a formative asymmetric division in the root pericycle, a study in which the network has a world-leading position. Besides molecular genetics, a chemical genomics approach will be used to study the early events in lateral root initiation. (P1, EU1)

- What is the involvement of plant hormones in root growth and architecture? The IAP network will deal with the role of auxins, cytokinines, ethylene and gibberillines in root development. (P1, P2, EU1)

- The current IAP V network has yielded a large amount of transcript profiles of intact roots; auxin treated roots; and of root pericycle cells. In the IAP VI network we would like to extend this to the analysis of the proteome. A highly interesting question is the comparison of the transcriptome and proteome of roots. (P1, P4, P2, P3)

- What is the relationship between roots and shoots? In the current IAP network it was established that root derived signals influence the initiation of flowering. What is the molecular basis of this root/shoot communication? (P2, P1, P4)

- How do roots sense abiotic stress? The IAP VI network will deal with root responses to the heavy metal, cadmium; a shortage of the mineral magnesium; and on Fe deficiency. (P3, P4, P1, P2).

- How can root growth be modelled? The aim is to obtain a mathematical model integrating the molecular regulation of cell division activity, cell elongation and transport of hormones with growth and architectural characteristics of roots. (P4, P1, EU1)


Answering these questions represents the challenging objective of this network and will be enabled by a strategy composed of six work packages in which a high level of interactions between the six partners will be achieved. Each partner has its unique research approach and background ranging from plant physiology, biochemistry to genetics and molecular biology. It is the interplay of the different disciplines and techniques within the work packages that will constitute the basis for a successful network.
In addition to the standard techniques available in the various labs, this network aims at the implementation of novel techniques that have only recently been established by some partners and that represent a major added value. The integrated advanced technical platforms will be available to all partners and include:

- Proteomics
- Chemical genetics: high throughput screening of large chemical libraries as tool to detect key-factors in root developmental processes
- Fluorescence Activated Cell Sorting (FACS): sorting of cells from roots to analyse cell and/or tissue-specific processes.
- Kinematics: high throughput analysis of cell expansion and cell division rates of roots to evaluate the effect of perturbation experiments via mutations, transgenics or various chemical treatments.
- Optical techniques: polarization confocal microscopy and Field Emission Scanning Electron Microscopy (FESEM) to map root cell wall architecture

Finally, this Belgian Arabidopsis Root Network will create a spiritual climate within Belgium by organising regular project meetings, an international root symposium and pre- and postdoc training sessions. This will certainly strengthen further the already existing contacts and collaborations between the various partners and will be essential in the exchange of students between the involved universities.