News Release

Hormone clue to root growth

Nottingham scientists shed light on how a hormone helps control plant root growth

Peer-Reviewed Publication

University of Nottingham

Plant roots provide the crops we eat with water, nutrients and anchorage. Understanding how roots grow and how hormones control that growth is crucial to improving crop yields, which will be necessary to address food security and produce better biofuels.

Now an international group of scientists, led by the Centre for Plant Integrative Biology at The University of Nottingham, has shed light on how a plant hormone is crucial in controlling the growth of plant roots.

Plant growth is driven by an increase in two factors: the number of cells, and their size. It is already known that the plant hormone gibberellin controls how root cells elongate as the root grows in the model plant Arabidopsis thaliana. Now a paper appearing in Current Biology describes for first time how this hormone also regulates the number of cells in the root in order to control root growth.

Gibberellin normally acts by signaling the removal of proteins which repress growth, and so promotes root cell production. The new research shows that mutant plants that do not produce gibberellin are unable to increase their cell production rate and the size of the root meristem, the zone of cell proliferation.

Plants in which the cells in the meristem were made to express a mutant version of the growth-repressing protein GAI not degraded by gibberellin showed disrupted cell proliferation. Expressing this mutant form, gai, in only one tissue, the endodermis (the innermost layer of the root cortex of a plant), was sufficient to stop the meristem enlarging. In effect, the rate of expansion of dividing endodermal cells dictates the equivalent rate in other tissues.

This research was headed by Dr Susana Ubeda-Tomás and Professor Malcolm Bennett of the Centre for Plant Integrative Biology, in collaboration with scientists in Nottingham, Cambridge, Edinburgh, Spain, Belgium and Sweden.

Professor Malcolm Bennett, Biology Director for the Centre for Plant Integrative Biology and Professor of Plant Sciences in the Division of Plant and Crop Sciences, said: "We have shown that gibberellin plays a crucial role in controlling the size of the root meristem, and that it is the endodermis which sets the pace for expansion rates in the other tissues.

"Understanding precisely how hormones regulate plant growth is one of the key areas of fundamental plant biology which will underpin crop improvements in the future."

The Centre for Plant Integrative Biology (CPIB) is funded by the Systems Biology joint initiative of BBSRC and EPSRC, which has provided £27 million for six specialised centres across the UK.

The Division of Plant and Crop Sciences at The University of Nottingham is one of the largest communities of plant scientists in the UK. Around 160 people work in the Division, which welcomes visiting scientists from all over the world, reinforcing its reputation as a world renowned centre.

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Notes to editors: The University of Nottingham is ranked in the UK's Top 10 and the World's Top 100 universities by the Shanghai Jiao Tong (SJTU) and Times Higher (THE) World University Rankings.

More than 90 per cent of research at The University of Nottingham is of international quality, according to RAE 2008, with almost 60 per cent of all research defined as 'world-leading' or 'internationally excellent'. Research Fortnight analysis of RAE 2008 ranks the University 7th in the UK by research power. In 27 subject areas, the University features in the UK Top Ten, with 14 of those in the Top Five.

The University provides innovative and top quality teaching, undertakes world-changing research, and attracts talented staff and students from 150 nations. Described by The Times as Britain's "only truly global university", it has invested continuously in award-winning campuses in the United Kingdom, China and Malaysia. Twice since 2003 its research and teaching academics have won Nobel Prizes. The University has won the Queen's Award for Enterprise in both 2006 (International Trade) and 2007 (Innovation — School of Pharmacy), and was named 'Entrepreneurial University of the Year' at the Times Higher Education Awards 2008.

Nottingham was designated as a Science City in 2005 in recognition of its rich scientific heritage, industrial base and role as a leading research centre. Nottingham has since embarked on a wide range of business, property, knowledge transfer and educational initiatives (www.science-city.co.uk) in order to build on its growing reputation as an international centre of scientific excellence. The University of Nottingham is a partner in Nottingham: the Science City.

More information is available from Dr Susannah Lydon, Outreach Officer in the Centre for Plant Integrative Biology, on +44 (0)115 95 16289, susannah.lydon@nottingham.ac.uk; or Media Relations Manager Simon Butt in the University's Communications Office on +44 (0)115 951 5793, simon.butt@nottingham.ac.uk

More University of Nottingham news: http://communications/nottingham.ac.uk/


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