Philip Brewer and thale cress
Philip Brewer and thale cress

A sustainable increase in worldwide crop yields could flow from a new discovery about a plant hormone, led by researchers at The University of Queensland.

Professor Christine Beveridge, of UQ’s School of Biological Sciences and the Queensland Alliance for Agriculture and Food Innovation, said the discovery held promise for helping to meet global food security targets.

“Increasing food crop yields is essential to feeding the world’s growing population,” said Professor Beveridge, a world leader on plant development hormones.

“We have discovered a ‘missing enzyme – one that we had tried to identify for some time, because it helps regulate plant growth and development.”

Professor Beveridge said researchers in her lab had been studying “the long-distance signalling process” that some plants used to regulate their growth and development process.

The signalling hormone strigolactone was known to be involved in plant branching.

“Strigolactones were first discovered as exuded from roots and stimulating devastatingly parasitic weeds, some of which have been found in Australia,” Professor Beveridge said.

“Strigolactones are also important in stimulating symbioses with particular fungi that greatly enhance nutrient uptake from soils in natural and cropping systems.”

In a paper published today in the Proceedings of the National Association of Science, Professor Beveridge’s team reported using an innovative method to discover a gene called Lateral Branching Oxidoreductase that acts in the strigolactone production pathway.

With researchers from Japan, China, the University of Western Australia, Australian National University, Queensland Department of Agriculture and Fisheries, and the University of Tasmania, they demonstrated that the gene acted to produce a new type of strigolactone.

“This is significant because it demonstrates that more than one strigolactone may be functional in plants,” Professor Beveridge said.

Professor Stephen Smith of the University of Tasmania said the discovery opened the possibility of modifying plant architecture and yield “without affecting symbiosis and nutrient uptake”.

He said strigolactone levels had been associated with natural variation in “tillering” – shoot architecture and branching – in rice and were considered important in breeding.

As a model plant, the researchers used thale cress (Arabidopsis thaliana), a small flowering plant related to cabbage and mustard.

Thale cress is commonly used for studying plant biology and is the first plant to have its entire genome sequenced.  International libraries of materials are available to researchers to study the plant’s DNA.

Professor Beveridge said the hormonal control of plant development and shoot architecture underpinned the yield, productivity and ornamental value of crops, trees and shrubs.

Research such as that undertaken by her team was vital, because the United Nations estimated the world’s current population of 7.4 billion would reach 11.2 billion by the year 2100.

Professor Beveridge is one of UQ’s most senior scientists, having been elected last year as a Fellow of the Australian Academy of Science.

Media: Professor Christine Beveridge, c.beveridge@uq.edu.au, +61 7 3365 7525.

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