York researchers discover how the garden grows
Posted on 25 May 2005
But the reasons why they should have such a beneficial effect on bushes, plants and trees has been shrouded in mystery.
Now academics at the University of York have uncovered the secret of the role the plant hormone auxin plays in growth.
The discovery by Professor Ottoline Leyser and Dr Stefan Kepinski, of the University's Department of Biology, could eventually help to develop more productive tomato plants, more beautiful roses and even more efficient and user-friendly renewable energy crops.
Pruning works because the leading shoot produces auxin which is pumped down the plant and inhibits the growth of side shoots
Professor Ottoline Leyser
The existence of auxin was predicted by Charles Darwin in the 1880s and finally established by researchers more than 70 years ago. It plays a critical role in nearly every aspect of the growth and development of a plant, but the mechanism it uses to exert such fundamental effects has puzzled scientists.
Now Professor Leyser and Dr Kepinski have identified the elusive auxin receptor which binds the hormone in the cells.
Professor Leyser, who has been researching auxin for 15 years, said: "The auxin receptor is the first element in the signalling process. It is the way that cells know how much auxin there is, and so how to respond, by for example, changing their shoot branching"
"Pruning works because the leading shoot produces auxin which is pumped down the plant and inhibits the growth of side shoots. Once the main shoot is removed, the auxin disappears and the side shoots grow out. The only way the side shoots know that the auxin is gone, is because it is no longer binding to the auxin receptor."
The research is likely to have a range of agricultural and horticultural applications such as in the search for sustainable energy sources. In collaboration with researchers at Rothamstead Research Station, Professor Leyser is starting to examine the phenomenon in willow, which is increasingly grown in short rotation coppicing as a renewable energy crop, for biomass.
"With willow-breeding for biomass, the goal is to achieve between four and eight reasonably substantial side shoots emerging after coppicing. This discovery could help to develop the most efficient and user-friendly willow for biomass production," Professor Leyser said.
"But the applications are much wider because auxin is so important in many different aspects of plant growth. For example, it enables shoots to grow towards the light, and it is the active ingredient in rooting powder."
The York researchers have reached the same conclusions on auxin receptors as a team from Indiana University in the USA, though the American researchers approached the problem differently. The results of both pieces of research are published in the latest issue of Nature.
Notes to editors:
- Nature articles are Molecular biology: Elusive plant hormone receptor identified (pp. 441-451; N&V).
- The University of York's Department of Biology is one of the leading centres for biological teaching and research in the UK. The Department has an integrated approach to Biology, with no barriers between disciplines. It both teaches degree courses and undertakes research across the whole spectrum of modern Biology, from molecular genetics and biochemistry to ecology.
- The research at Indiana University was carried out by Professor Mark Estelle, Dr Nihal Dharmasiri and Dr Sunitta Dharmasiri.