Plant gene responsible for production of beta glucan, a cereal carbohydrate with potential health benefits

Researchers have identified a gene from barley which is required for the production of the complex carbohydrate beta glucan.

By breeding this trait into wheat, they hope to create a healthier grain which may offer cholesterol-lowering and bowel health promoting properties, and increase the versatility of wheat.

"The discovery of this gene function provides new insight into how plants produce beta glucan, and has implications for human health," said research leader Dr Monika Doblin, from the University of Melbourne.

Beta glucan is a complex carbohydrate (polysaccharide), which is a soluble fibre believed to be effective in lowering blood cholesterol and promoting bowel health. It is present in oats and barley, but in relatively low levels in wheat.

"Because wheat is used in so many of the products we consume, researchers will now work to raise the soluble fibre content in wheat to give improved health benefits," Dr Doblin said.

Dr Doblin is lead author on the study published this week in the early edition of this month’s Proceedings of the National Academy of Sciences.

This research builds on work initially funded by the Grains Research and Development Corporation and is currently undertaken as part of the High Fibre Grains Cluster – a research collaboration between the CSIRO’s Food Futures Flagship and the Universities of Melbourne, Queensland and Adelaide.

The gene, known as CSLH (cellulose synthase-like H), is a member of a second family of genes (both discovered by this research team) shown to be involved in the production of beta glucan. Researchers hope that the presence of the two families of genes will give more options in breeding the healthier traits into wheat.

Researchers took the beta glucan gene from barley and expressed it in the model laboratory plant Arabidopsis, which does not produce the carbohydrate. They were able to demonstrate that the gene was responsible for production of the carbohydrate by confirming the presence of beta glucan in Arabidopsis using sophisticated microscopic and chemical techniques.

Professor Tony Bacic, University of Melbourne’s Cluster team leader, said the next step is to continue to validate the results by looking at ‘over expression’ of the gene in the system it came from, the barley plant.

"We also want to establish if other genes are involved in making beta glucan and how this process is regulated in order to increase its levels effectively in wheat for increased health benefits," Professor Bacic said.

Professor Mike Gidley, from the University of Queensland and Leader of the High Fibre Grains Cluster, said the research group’s goal is to create grains with superior fibre content for health benefits and offer value to industry.

"We are aiming to increase the levels of beneficial beta glucan in wheat to enhance nutritional properties," Professor Gidley said. "We want to make our grains healthier while ensuring we can still use them to make the range of food products we currently enjoy from wheat, such as bread, cereal and pasta."

Dr Bruce Lee, Director of CSIRO’s Food Futures Flagship, said this research Cluster is now delivering on some of the research group’s original goals. "The production of crops that can be used to produce foods with potential health benefits in cholesterol reduction and improved bowel health would also provide Australia with a significant advantage in the market place," he said.

The study was jointly conducted by researchers from the Australian Centre for Plant Functional Genomics, who are based at the Universities of Melbourne (led by Professor T Bacic and Associate Professor EJ Newbigin) and Adelaide (led by Professor GB Fincher and Dr R Burton).

(Source: University of Melbourne: Proceedings of the National Academy of Sciences: April 2009)