The big unknown: plant virus biodiversity.

Studies on plant virus biodiversity are in their infancy, but with new technologies we can expect to see more information about novel plant viruses in the near future. The challenge for virus biodiversity work is that viruses do not have any universal coding sequence, such as ribosomal RNAs found in all cellular life. These obstacles are being overcome in clever ways. Understanding what exists in our natural environment will help us to tackle big issues in agriculture, such as disease emergence and the use of beneficial viruses and other microbes. Copyright Â