CIP scientists hope to crack the RNA silencing code to stamp out plant viruses.

Currently, eliminating a virus from an infected plant requires considerable time and money. The price is more than US$500, and the process can take up to a year. Searching for a more cost- and time-effective solution, scientists at the International Potato Center (CIP) are hoping to crack the RNA silencing code that will enable them to add modified RNA to a test tube − and in a simple, one-step process, rid the plant of viral infection.

“Basically, it’s a like a plant vaccine,” says Jan Kreuze, Principal Virologist at CIP.

Viruses are pieces of DNA or RNA (a variant of DNA) that fool the plant into copying and spreading them, causing disease in the process. Plants can defend themselves against viruses using a class of small RNAs called small interfering RNA (siRNA). The siRNA recognizes the viruses and destroys them by cutting their DNA or RNA into tiny pieces. This process is called RNA silencing. But the plant does not always win the battle, so CIP scientists are looking to find ways to boost the plant’s defense through its RNA silencing mechanism.

Kreuze is leading an innovative research project, which is being carried out by CIP and the Crop Research Institute of Norway with support from Grand Challenges Explorations, an initiative funded by the Bill & Melinda Gates Foundation. The researchers hope to resolve the age-old problem of virus infection in plants, which causes enormous crop losses in major food staples. Crops such as sweetpotato, cassava, yams, bananas, and potatoes are prone to virus infection over successive generations, because they are grown vegetatively and not from seeds. The only way to eliminate viruses in infected plants is through a laborious, time-consuming process that involves a combination of heat or cryotherapy treatment with meristem tip culture. It is a process that has advanced little since its inception over 60 years ago.

“Basically we’re going to add bullets (siRNA) to the plants’ defense arsenal. It’s science fiction right now, but if it works, then the lengthy, expensive cleanup process could be shortened to two minutes,” says Dr. Kreuze.

If successful, Dr. Kreuze and his team will produce “kits” containing appropriate cocktails for different crop viruses. The project will be tested on potato initially, however the technique will be applicable to a wide range of viruses and crops.