Using CRISPR/Cas9 editing to inactivate an endogenous virus impacting bananas (Commun. Biol.)

Banana streak virus (BSV) is a plant pathogenic pararetrovirus that has integrated into the genome of banana Musa spp., reducing crop production. When BSV-infected banana plants become stressed, BSV reactivates to create functional infectious viruses that can cause lethal tissue necrosis. Tripathi et al. used CRISPR/Cas9 to inactivate endogenous BSV, preventing plants from becoming symptomatic during drought which would otherwise cause them to become diseased. The three open-reading frames in BSV were targeted by CRISPR to produce frameshift mutations with low occurrence of off-target effects, and a knockout of all three was important to completely inactivate BSV. This study is the first to knock out integrated viral DNA from a host plant genome, demonstrating that CRISPR/Cas9 targeted mutagenesis can permanently inactivate endogenous viruses. Knocking out BSV in other banana cultivars would provide a wealth of previously unexplored germplasm for use in breeding and prevent further decimation of crops. (Summary by Katy Dunning) Commun. Biol. 10.1038/s42003-019-0288-7