Plants that have been engineered to contain the CRISPR–Cas9 system are resistant to viral infections that reduce crop yields.

The CRISPR system, first discovered in bacteria, uses certain RNA molecules as guides to recognize specific DNA sites in genomes that the Cas9 enzyme then cuts. Two groups of researchers have designed guide RNAs to target and disrupt DNA from geminiviruses, which infect many crops. Caixia Gao of the Chinese Academy of Sciences' Institute of Genetics and Developmental Biology in Beijing and her colleagues focused on the beet severe curly top virus. They found that transgenic CRISPR–Cas9 plants had 60–80% less viral DNA than control plants, and did not show disease symptoms such as leaf curling. Similarly, Daniel Voytas of the University of Minnesota in Minneapolis and his colleagues targeted the bean yellow dwarf virus genome and found 5–87% less viral protein in infected engineered plants.

This strategy could be used to develop disease-resistant transgenic plants, the teams say.

Nature Plants http://dx.doi.org/10.1038/nplants.2015.144 (2015); http://dx.doi.org/10.1038/nplants.2015.145 (2015)