CRISPR gene editing tool to control pests

Using the CRISPR gene editing tool, Nikolay Kandul, Omar Akbari and their colleagues at UC San Diego and UC Berkeley have developed a new way to control and suppress populations of insects, potentially including those that ravage agricultural crops and transmit deadly diseases, reports ScienceDaily.

The ‘precision-guided sterile insect technique’ alters key genes that control insect sex determination and fertility. When pgSIT eggs are introduced into targeted populations, only adult sterile males emerge, resulting in a novel, environmentally friendly and relatively low-cost method of controlling pest populations in the future.

Eradicate target species locally

“CRISPR technology has empowered our team to innovate a new, effective, species-specific, self-limiting, safe and scalable genetic population control technology with remarkable potential to be developed and utilized in a plethora of insect pests and disease vectors,” said Akbari, an assistant professor in UC San Diego’s Division of Biological Sciences. “In the future, we strongly believe this technology will be safely used in the field to suppress and even eradicate target species locally, thereby revolutionizing how insects are managed and controlled going forward.”

_{Text continues underneath image}

The new pgSIT uses CRISPR to simultaneously disrupt key genes that control female viability and male fertility in pest species. – Image: Nikolay Kandul, Akbari Lab, UC San Diego

Sterile male progeny with 100 % efficiency

The new pgSIT (precision-guided sterile insect technique), developed over the past year-and-a-half by Kandul and Akbari in the fruit fly Drosophila, uses CRISPR to simultaneously disrupt key genes that control female viability and male fertility in pest species. pgSIT, the researchers say, results in sterile male progeny with 100 % efficiency. Because the targeted genes are common to a vast cross-section of insects, the researchers are confident the technology can be applied to a range of insects, including disease-spreading mosquitoes.

Eggs can be shipped to any location

The researchers envision a system in which scientists genetically alter and produce eggs of a targeted pest species. The eggs are then shipped to a pest location virtually anywhere in the world, circumventing the need for a production facility on-site. Once the eggs are deployed at the pest location, the researchers say, the newly born sterile males will mate with females in the wild and be incapable of producing offspring, driving down the population.

_{Text continues underneath image}

A anti-pest worker shows a locust in an oasis, some 20 kilometers of Iche, southeastern Morocco. Using pgSIT, eggs can be shipped to a pest location virtually anywhere in the world, circumventing the need for a production facility on-site. – Photo: AFP

“This is a novel twist of a very old technology,” said Kandul, an assistant project scientist in UC San Diego’s Division of Biological Sciences. “That novel twist makes it extremely portable from one species to another species to suppress populations of mosquitoes or agricultural pests, for example those that feed on valuable wine grapes.”

Dead end

The new technology is distinct from continuously self-propagating “gene drive” systems that propagate genetic alterations from generation to generation. Instead, pgSIT is considered a “dead end” since male sterility effectively closes the door on future generations.

“The extension of this work to other insect pests could prove to be a general and very useful strategy to deal with many vector-borne diseases that plague humanity and wreak havoc an agriculture globally,” said Suresh Subramani, global director of the Tata Institute for Genetics and Society.

Also read: Could a fungus help farmers reduce pesticide use?