The life of a plant that we depend on for food, clean air, and materials are challenged by myriad threats, natural and man-made including Viruses, pests, fungi, herbicides, drought, pollution, salinity, flooding, and frost. These rapid or unexpected emergence of these threats put human food security at risk and could lead to destabilization of the economy which depends a great deal on agriculture.
Yet, in this modern age of biological weapons, agriculture and agricultural products have been targeted by various nation states as viable strategic targets as well as targeted by terrorists (aka non-state actors) for acts of bioterrorism. Number of analysts have pointed out that terrorist attacks on livestock or crops, although unlikely to cause terror, are also a concern because they could be executed much more easily and could have serious economic consequences. National security can be quickly jeopardized by naturally occurring threats to the crop system, including pathogens, drought, flooding, and frost, but especially by threats introduced by state or non-state actors.
Farmers and others responsible for plant health use longstanding tools such as crop rotation, selective breeding, pesticides, slash-and-burn clearing, and quarantine to shelter plants and defend against the worst effects of pathogens, pests, and environmental insults, but these methods can be slow, inefficient, and damaging to the environment, and may require extensive and expensive infrastructure. And while scientists and farmers are increasingly turning to molecular techniques to improve resilience in plant varieties, today’s genomic tools generally do not allow for alteration of mature plants.
A new DARPA program is poised to provide an alternative to traditional agricultural threat response, using targeted gene therapy to protect mature plants within a single growing season. In the process, DARPA aims to transform certain insect pests into “Insect Allies,” the name of the new effort. DARPA proposes to leverage a natural and very efficient two-step delivery system to transfer modified genes to plants: insect vectors and the plant viruses they transmit.
“Insects eat plants and insects transmit the majority of plant viruses,” said Blake Bextine, the DARPA program manager for Insect Allies. “DARPA plans to harness the power of this natural system by engineering genes inside plant viruses that can be transmitted by insects to confer protective traits to the target plants they feed upon.”
The Insect Allies program is pursuing scalable, readily deployable, and generalizable countermeasures against potential natural and engineered threats to the food supply with the goals of preserving the U.S. crop system.
Insect Allies seeks to mitigate the impact of these incursions by applying targeted therapies to mature plants with effects that are expressed at relevant timescales—namely, within a single growing season. Such an unprecedented capability would provide an urgently needed alternative to pesticides, selective breeding, slash-and-burn clearing, and quarantine, which are often ineffective against rapidly emerging threats and are not suited to securing mature plants.
To develop such countermeasures, Insect Allies performer teams are leveraging a natural and efficient two-step delivery system to transfer modified genes to plants: insect vectors and the plant viruses they transmit. The program’s three technical areas—viral manipulation, insect vector optimization, and selective gene therapy in mature plants—layer together to support the goal of rapidly modifying plant traits without the need for extensive infrastructure. Since the start of the program, Insect Allies teams with expertise in molecular and synthetic biology have demonstrated mounting technical breakthroughs that are providing foundational knowledge in plant virus gene editing and disease vector biology from which the program will continue to build.
DARPA emphasizes biosafety and biosecurity in this research. All work is conducted inside closed laboratories, greenhouses, or other secured facilities; DARPA is not funding open release.
Insect allies can be used for Biological warfare
Experts have waned that kind of technology could easily be used for biological warfare. Dr Guy Reeves, an expert in GM insects at the Max Planck Institute for Evolutionary Biology, said that there has been hardly any debate about the technology and the programme remains largely unknown “even in expert circles”.
He added that despite the stated aims of the programme, it would be far more straightforward using the technology as a biological weapon than for the routine agricultural use suggested by Darpa.
“It is very much easier to kill or sterilise a plant using gene editing than it is to make it herbicide or insect-resistant,” explains Reeves. Experiments are reportedly already underway using insects such as aphids and whiteflies to treat corn and tomato plants.
“Because of the broad ban of the Biological Weapons Convention, any biological research of concern must be plausibly justified as serving peaceful purposes,” explained Professor Silja Voeneky, a specialist in international law at Freiburg University. “The Insect Allies Program could be seen to violate the Biological Weapons Convention, if the motivations presented by Darpa are not plausible.
Firstly, they note that if farmers wanted to use genetically modified viruses to improve their crops, there is no reason not to use conventional spraying equipment. They also noted that despite Darpa stating that no insects used should survive longer than two weeks, if such safeguards were not in place “the spread could in principle be unlimited”.
Mr Beck added: “The quite obvious question of whether the viruses selected for development should or should not be capable of plant-to-plant transmission – and plant-to-insect-to-plant transmission – was not addressed in the Darpa work plan at all”.
A spokesperson from Darpa defended the programme, explaining that using insects to apply these gene altering treatments could provide advantages over sprays.
“Most importantly in this context, sprayed treatments are impractical for introducing protective traits on a large scale and potentially infeasible if the spraying technology cannot access the necessary plant tissues with specificity, which is a known problem,” they said.
“If Insect Allies succeeds, it will offer a highly specific, efficient, safe, and readily deployed means of introducing transient protective traits into only the plants intended, with minimal infrastructure required.”