DuPont identifies gum gene

US researchers from Pioneer Hi-Bred International, a subsidiary of DuPont, have identified a gene found in guar that produces galactomannan, a gum that is commonly used as a food additive. The hope is that inserting the gene in commercial crops will help to provide a regular and cheap gum supply.

The US currently imports most guar and all locust bean gums from South Asia or the Mediterranean. The problem with this is that the prices of gums fluctuate because of seasonal variations in crop performance.

The Pioneer team worked with a researcher from the Indian Institute of Technology in Rourkee, India, to identify the gene that encodes mannan synthase (ManS). This enzyme forms the mannan backbone of galactomannan, a storage polysaccharide found in guar seeds. Researchers have until now struggled to identify the gene which encodes the enzyme.

They inserted the guar ManS gene into soya bean plants, which do not have any natural ManS activity. Preliminary tests showed that the GM soya bean seeds produced soya plants with a high ManS activity.

The Pioneer team hopes that producing galactomannan gums in high-yielding commercial crops such as soya should help to stabilise gum supply and price. The researchers also hope to be able to use other plant species to produce gums of high value, as well as novel gums.

Emma Davies