Construction of Attenuated Viruses by Changing the UpA Dinucleotide Frequency

Cross protection with an attenuated virus is a promising strategy for controlling viral diseases in crops that lack resistance resources. Attenuated viruses are usually obtained from naturally avirulent strains or through mutagenesis. Studies have shown that increasing the UpA dinucleotide content in the genome without altering the amino acid encoding sequence causes the loss of virulence. This chapter describes a detailed protocol for developing attenuated virus by increasing the UpA dinucleotide content, using turnip mosaic virus as a case study. This approach enables the rapid acquisition of stably, inheritable attenuated virus strains.