The silent revolution in molecular biology

RNA interference (RNAi), CSIRO’s patented gene silencing technology, is enabling researchers around the world to protect plants and animals from diseases, and to develop new plant varieties with beneficial attributes.

CSIRO has provided research materials to 3700 laboratories around the world and has issued more than 30 research and commercial licences for RNAi to date.

Global forestry company FuturaGene is the latest of public and privately funded organisations worldwide to license the technology which enables scientists to reduce or switch off the activity of single genes, with enormous benefits, especially in agriculture. FuturaGene will use RNAi technology to develop more resilient forestry crop varieties, primarily eucalyptus and poplar.

Technologies for preserving and enhancing yield in renewable plantations are an imperative for meeting growing wood demand in the face of climate change and increasing pest and disease threats, while preserving natural forests.

Other uses of RNAi technology include developing potatoes that don’t go brown, animal feed that’s easier to digest and an improved industrial oil.

Senior Research Scientist with CSIRO Agriculture and Food Ming-Bo Wang was one of the scientists involved in RNAi’s development in the mid-1990s, and together with colleague Peter Waterhouse, received the 2007 Prime Minister’s Prize for Science for the work.

“One of the projects we were working on at the time was with the potato chip industry; we were trying to develop a virus-resistant potato,” Dr Wang said.

“We discovered that when plants are attacked by viruses they use double-stranded RNA to mount a counterattack.

“We realised we could make use of this ‘virus immune’ response to develop a mechanism that would stop individual genes from passing on information.

“At first we didn’t think much of it but when we realised we’d uncovered a fundamental mechanism for silencing genes, we knew there would be widespread applications.”

The RNAi mechanism was used by US company Simplot to develop the ‘Innate’ potatoes that bruise less than other potato varieties. The potatoes also produce less acrylamide, a chemical which can accumulate in starchy foods such as potatoes when they are cooked at high temperatures.

Forage Genetics has licensed RNAi to develop an animal feed that is more easily digested. Alfalfa (or lucerne) is an important source of cattle feed in many countries. One major challenge for farmers is that if harvested late, alfalfa can contain high levels of lignin, the fibrous material that is important for binding cells, fibres and vessels in plants. Animals are unable to digest lignin.

HarvXtra alfalfa has up to 20% less lignin, making it much more digestible for cattle. It can also be harvested seven to 10 days late without sacrificing quality.

CSIRO itself has made use of RNAi to develop safflower seed oil that contains over 93% oleic acid, a valuable component in industrial chemicals and lubricants. Super high oleic oil safflower is being commercialised by GO Resources.

Dr Wang said that while there are more recent gene editing tools, RNAi will have a major role to play for many years to come because of its ability to silence multiple genes at the same time and tone down the expression of essential genes without killing a plant. He said that CSIRO was continually developing new tools, technologies and techniques to improve RNAi delivery, potency and ease of use.

Image credit: Using gene silencing technology, CSIRO developed safflower seed oil that contains over 93% oleic acid. Image courtesy of CSIRO.