Few things are scarier to a pumpkin farmer than the letters CMV. They stand for cucumber mosaic virus, a pathogen that lays waste to entire fields of pumpkins, cucumbers, and melons. Now, researchers have found a way to quickly develop vaccines that could eventually protect crops from viral pathogens.
“This is a really neat finding,” says Anna Whitfield, a plant pathologist at North Carolina State University in Raleigh who was not involved in the study. Viruses are an ever-evolving threat to global food security, Whitfield says, and the new technique might help farmers keep up with the constantly changing pathogens.
When a virus infects a plant cell, it often releases RNA—either in the form of messenger RNA or double-stranded RNA—which travels through the cell, helping the virus replicate. Defense proteins inside the plant cell recognize these viral RNAs, and enzymes that act like tiny scissors slice them apart. Some of the resulting bits and pieces of RNA, called small interfering RNAs (siRNAs), team up with a group of proteins called the Argonaute complex. The siRNAs serve as identifiers that lead the Argonaute complex to RNA on the virus genome, which the Argonaute complex and other proteins then destroy.
The tactic is deadly, but not always efficient. Of the many thousands of various siRNAs made by the plant, very few have the right chemical properties to fight the viral RNA. Biochemist Sven-Erik Behrens at Martin Luther University Halle-Wittenberg in Germany and his colleagues set out to streamline the process.
