Scientists might soon be able to transform wilting, diseased crops into healthy ones by releasing colonies of benign insects onto a field.
Current selective breeding techniques can produce plant seeds that are often better at resisting devastating diseases, but this process takes many years. Once a new disease threat hits a mature crop population, there’s no quick antidote available that farmers and scientists can rapidly deploy to protect these plants except for expensive and often toxic pesticides.
To address this problem, scientists at the Defense Advanced Research Projects Agency (DARPA) want to capitalize on insects’ natural relationships with plants. They believe the insects can transmit viruses carrying beneficial genetic traits to the plants they feed on.
“What we want to do is try to generate tools that will allow us to stabilize the food supply both domestically and internationally,” says Blake Bextine, the DARPA scientist overseeing the program.
The agency wants to use an approach called gene therapy to protect and rejuvenate crops from diseases—both naturally occurring ones and biothreats. Gene therapy uses harmless viruses as a vehicle to carry new genetic material to cells in an attempt to correct or reverse disease symptoms. Scientists think insects, which are the natural carriers of most plant viruses, could shuttle defensive genes to crops. Insects can be quickly bred and released within the same growing season.
DARPA is soliciting proposals from academic and industry scientists to develop a plant virus capable of carrying and delivering genetic material to a mature plant. Investigators will then have to figure out which insect species would deliver the viruses.
Researchers have been working on such a therapy for a bacterial disease called greening, which is transmitted by insects and has decimated Florida’s citrus crop for the past decade. Jacqueline Fletcher, the founder and former director of the National Institute for Microbial Forensics & Food and Agricultural Biosecurity at Oklahoma State University, says the DARPA project could help spur that therapy’s development.
Ideally, the technology could be used for important agricultural commodities, such as corn, wheat, and soybeans in the U.S., and cassava, a staple crop in many developing countries, especially in sub-Saharan Africa.
Bextine says this approach is preferable to insecticide spray, which can be expensive and inefficient, since substantial amounts of these products never reach their intended target. Spray technology is also much less common in developing countries.
For now, the gene therapy experiments will be conducted in laboratories or other contained spaces. DARPA hopes the technology will be ready to be released in the field in four years.