There are at least 1,000 different kinds of plant viruses that exist in nature. They can wipe out large areas of farmland and pose a huge threat to agriculture. 

However, scientists in China are using the natural defense mechanisms of plants as a means of virus control.

Farmers have known for years that a plant's shoot tip is a way to grow new plants without passing on a virus.

This is because the shoot tip holds crucial stem cells – which are very important, because without them, the plant dies. 

Studies have found that viruses stop when they reach cells containing a specific protein, called Wuschel. 

And it is not a coincidence – when injecting this protein into other parts of the plant, the viruses retreat. 

Zhao Zhong, from the University of Science and Technology of China, explains: "In previous research, we only found the Wuschel protein is necessary for maintaining the stem cells. The stem cells would not be maintained. We never knew it has this ability to protect against viruses."

He says that at the moment it is only found in plants' shoot tips, but the hope is that they will be able to expand the same mechanism into leaves, so the whole plant can be protected.