Plant science: a multidisciplinary approach
Meeting the food security challenge will require more than botanists looking at plants and zoologists examining animals. As biological disciplines become ever-more mathematical and discovery dependent upon a sound understanding of the biophysics involved, maintaining and increasing progress is likely to come from interdisciplinary teams of scientists.
In the UK, the Centre for Plant Integrative Biology (CPIB) at the University of Nottingham brings together biologists, engineers, mathematicians and computer scientists to answer questions about plant science. The centre uses experimental data and novel imaging apparatus to construct complex models to simulate the biological processes underlying plant growth and metabolism.
CPIB scientist Dr Caroline Howells.
Image: Tim Gander
A major focus of the work is devoted to understanding roots. When plants have beautiful flowers and fine foliage, it’s easy to forget that half the organism lives underground, and it’s from the soil that plants derive water and nutrients essential for growth.
Using the well-understood model plant Arabidopsis thaliana, CPIB researchers are therefore trying to reconstruct a ‘virtual root’ that will model growth and development on different scales, from sub-cellular metabolic processes to movements at the whole-organ level.
With an accurate ‘virtual root’, researchers can then manipulate hormones in the model and see if it matches up with the results of growing real plants. That, of course, requires a separate major effort to map the complex web of interactions between the principal plant hormones and their chemical intermediates.
These systems-oriented approaches are being applied to understand how the hormone auxin is distributed in epidermal cells in a root growing in response to gravity. Key genes that control lateral root emergence and the fine architecture of root structure are also being tackled in this way.
As the ‘lab rat’ of the plant world, the work will contribute to a protein atlas of the Arabidopsis root, which is being compiled using antibodies raised against several hundred key proteins that regulate root growth. The antibodies are currently deposited in NASC, the European Arabidopsis Stock Centre, for use by the wider international scientific community.
Special software automatically records root characteristics.
Image: Andrew French
Modelling an entire plant root system – from inside the cell to gross morphology – requires some specific and high-tech equipment, such as a special cell pressure probe allows the measurement and manipulation of cell turgor (pressure inside the cell) and an automatic microscope focusing system that uses an image-analysis feedback mechanism to maintain a crisp view on growing roots where focus drift over time can be a problem.
In addition, Microscale X-ray Computed Tomography (Micro-CT, a small version of a hospital CT scanner) is allowing researchers to visualise live roots growing in soil as it exists in the field. The aim is to identify genes that regulate key root-growing traits, such as root depth, angle and density, which can be used as molecular markers in crop breeding programmes to identify and assimilate with similar systems in other plants.
Bespoke software has also been developed at CPIB, such as RootTrace, which allows automatic and high throughput measure of root characteristics like length and curvature.