Geneticists Turn to Engineered Virus and CRISPR to Fight Citrus Disease

Southern Gardens Citrus in Clewiston, Florida, an agricultural company, has applied to the United States Department of Agriculture (USDA) in February for permission to use the engineered version of the citrus tristeza virus (CTV) to fight the bacterium that causes citrus greening. Citrus greening, or huanglongbing, is a disease that has slashed orange production in the US in half over the past decade, and threatens to destroy the US$3.3-billion industry entirely. The application's comment period has ended, and the USDA will now assess the possible environmental effects of the engineered virus.

Field trials of engineered CTV are being conducted and once the request is approved, it would be the first time this approach has been used commercially. It could also provide an opportunity to sidestep the regulations and public stigma related to genetically engineered crops.

The engineered virus is not the only option being explored to tackle citrus greening. Other projects aim to edit the citrus tree genome using CRISPR–Cas9 to make them more resistant to the pest, or to engineer trees that express defense genes or short RNA molecules that prevent disease transmission. Local growers have also helped to fund an international project that has sequenced citrus trees in the search for more weapons against citrus greening.

For more details, read the article in Nature News.