Mosaic viruses cause damaging diseases in several important crops. ~ Swiss botanist Hervé Vanderschuren
The cassava plant, also called manioc or yuca, is a staple root vegetable crop for its tuberous starch: tapioca. Cassava is subject to the mosaic virus, which retards growth and reduces yield.
Geneticists used CRISPR to try to make manioc resistant to the virus. The attempt failed spectacularly: provoking the virus to sharpen its virulence.
CRISPR applied to the virus encouraged it to evolve in a way that increased resistance to intervention. ~ Indian geneticist Devang Mehta