Biotech Updates

Scientists Develop Dual Disease Resistant Cassava

October 10, 2012

Scientists from the Swiss Federal Institute of Technology (ETH) in Zurich have developed new transgenic cassava variety that is resistant to a pair of viral diseases--these include the notorious brown streak virus which originated in East Africa and is threatening to spread to Central and West Africa.

In order to make cassava resistant to the brown streak virus, the researchers modified the genetic make-up of one variety of cassava to produce small interfering RNA molecules (siRNA). The plant produces the siRNA naturally after virus infection, but the researchers have now tricked cassava to produce the siRNA in all of its parts before the virus can infect it. This prevents the virus from multiplying and spreading throughout the plant.

To make the variety resistant to another disease, scientists used the Nigerian TME 7 cassava variety, also known as "Oko-iyawo". This variety is naturally resistant to cassava mosaic disease, which is caused by another virus that is severely impacting cassava production throughout Africa. A researcher involved in the project said that this resistance is not changed by the new resistance to the brown streak virus.

View ETH's news release at