A team of scientists at the University of Edinburgh has become the first to identify a gene which helps control plant growth. The researchers have pinpointed a gene called TCP20 that controls two biological processes which are fundamental to the development of plants - cell division and cell growth regulation. The discovery is not only crucial to scientific understanding of plant growth, but also opens up new possibilities in the field of plant breeding.

The research, published in the Proceedings of the National Academy of Sciences, identifies TCP20 in a mustard-like plant called Arabidopsis, though the gene is thought to be present in most plant species. Scientists had first predicted TCP20's existence five years ago, but, until now, it had proved difficult to pinpoint a specific gene that regulates both cell division and cell growth. Any gene that controls these two key functions therefore plays a crucial role in the growth process: division is the process by which cells multiply, with cells splitting in two to form daughter cells which, in turn, make more plant tissue; cell growth regulation is the mechanism that ensures new cells do not grow too big or become too small to sustain themselves.

By identifying TCP20, scientists will potentially be able to manipulate plant growth with a greater degree of sophistication than at present. Altering the activity of the newly-discovered gene could enable growers to lead to increase the size of leaves or roots - depending on the crop - thus producing bigger crop yields. It could also result in new varieties of ornamental plants, as growers initiate gene activity changes in flower buds to alter the shape of petals.

Dr Peter Doerner, of the University of Edinburgh's Institute of Molecular Plant Sciences, said: "Plants have stem cells just like animals, and just like in animals, these divide infrequently. Plants grow continuously to produce leaves, flowers and roots and, to ensure that enough cells are produced to make these organs, cell division and cell growth must be rapidly and forcefully regulated in the daughters of stem cells.

"Our research shows that this is accomplished through the TCP20 gene in Arabidopsis. This finding has fundamental importance for our understanding of plant growth and will affect plant breeding as well. Altered activity of this gene could affect the size of leaves or roots in crops, while activity changes restricted to just flower buds could, for example, change the shape of petals."