A fusion protein comprised of a densovirus coat protein, a proline-rich linker, and an insect-specific neurotoxin allows for the development of transgenic crops with resistance to lepidopteran (caterpillar) pests. Insects cause agricultural loss and economic damage worldwide. Caterpillar pests, such as the fall armyworm, are among the most notorious and difficult pests to manage, with resistance to current control methods hampering management efforts. Alternative, environmentally friendly, and economical methods are needed to reduce damage to crop and ornamental plants caused by insect infestation.
There is a growing shift from chemical insecticides toward eco-friendly biopesticide alternatives that offer effective pest control with reduced environmental impact. The biopesticide industry continues to grow both scientifically and economically. In 2024, the global biopesticides market was valued at USD 8.73 billion, and is projected to reach USD 28.61 billion by 2031.
Researchers at the University of Florida have developed a delivery system for insect-specific toxins that, when expressed by or delivered from a plant, will suppress lepidopteran pests. The coat protein of a densovirus that infects caterpillars can be used as a delivery vehicle for neurotoxins to their site of action within the body of the insect.
This approach enables the application of plant-incorporated protectants, reduces the need for chemical sprays, and targets a specific pest insect without negatively impacting off-target and beneficial species. The delivery system is equipped with gut-binding and transcytosis capabilities, offering a versatile and sustainable solution for managing agricultural pests for the delivery of diverse toxins that act within the hemocoel.
Plant-incorporated protectant for lepidopteran control in crops
The densovirus coat protein binds the gut epithelium and crosses into the hemocoel, or body cavity. When fused to a peptide toxin, the coat protein delivers the insecticidal peptides to their site of action. Because of the highly specific nature of both the delivery vehicle and the neurotoxins, non-target species remain unaffected. Current research demonstrates successful penetration of the gut epithelial layer in the fall armyworm and other lepidopteran species.
Caterpillars feed on a crop plant bioengineered to express the densovirus coat protein-neurotoxin fusion. Following ingestion, the fusion protein binds to the gut surface and then crosses the gut epithelium by transcytosis, delivering the neurotoxin to its site of action, namely the nerves on the surface of the gut. The neurotoxin is ineffective on ingestion without this delivery vehicle.