CRISPR’s future in human genetic editing remains to be seen, but it may be very useful in controlling agricultural pests.
Right now, a farmer’s best means of keeping insect pests from ruining their crops is a chemical such as insecticide, but with governmental bodies such as the EU clamping down on one of the most common ones out there last year, another alternative is needed.
Now, a team from the University of California San Diego has put forward the gene-editing tool known as CRISPR as one solution, by altering key genes that control insect sex determination and fertility.
The findings published to Nature Communications describe the new ‘precision-guided sterile insect technique’ – or pgSIT – whereby eggs derived from this method are introduced into targeted populations.
As a result, only adult sterile males emerge from the eggs. The team said this results in a novel, environmentally friendly and relatively low-cost method of controlling pest populations in the future.
The concept of sterilising male insects for population control is not new, having been in place since the 1930s. It was in the 1950s when researchers began irradiating males in the US to eliminate a pest species known as the screwworm fly.
‘A novel twist of a very old technology’
Now, instead of using radiation, pgSIT uses CRISPR to simultaneously disrupt key genes that control female viability and male fertility in pest species. This process results in sterile male progeny of 100pc.
Unlike similar methods that propagate genetic alterations from generation to generation, pgSIT is considered a ‘dead end’, since male sterility closes the door on future generations.
Because the targeted genes are common to a vast cross-section of insects, the researchers believe pgSIT can be designed to produce eggs of a targeted pest species anywhere in the world, such as mosquitoes. Once deployed in a region, the sterile males will be born, thereby driving down populations of the pest.
“This is a novel twist of a very old technology,” said Nikolay Kandul, an assistant project scientist in the university’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.”