Yes, you read that right: the newest form of pest control relies on no chemicals, no spraying, no inserted proteins, and no risk for species we aren’t trying to target.
This new method uses what’s called “RNA interference,” which is when double-stranded RNA is taken and, in an ancient form of protection from viruses, is used as a template for the destruction or deactivation of similar pieces of coding RNA. You, your pets, your plants, and I all use this to both regulate our own levels of gene expression and also defend ourselves against nasty viruses.
This technology has already been used increase antioxidants in strawberries and to create potatoes that produce less acrylamide when fried, and now it opens the door to a whole new form of extremely targeted pest control.
Previous attempts at pest control have centered around either the spraying, or genetic inclusion, of compounds which kill insects. Humanity has continually moved away from wide-spectrum pest control options like DDT into more targeted options like Bt, which is used both in organic (sprayed) and GMO (as a protein in the plants) farming. But, because Bt (like other compounds) is itself the “actor,” insects have been able to gain resistance.
A particular menace, dubbed an “international superpest,” is the Colorado Potato Beetle. It has repeated developed resistance to everything anyone has been able to throw at it, resisting convention as well as organic pesticides. Now, a new RNAi superweapon emerges to retake the field!
Unlike all other options, which rely on adding a chemical or a protein, this new RNA-based method is much harder for beetles to gain resistance to and even less likely to impact unintended targets. Presented in a new study by Zhang, Khan, Hasse et al, the scientists generated a highly effective form of pest control by adding genes transcribed to double-stranded RNA in the potato’s plastids (which are isolated compartments in which photosynthesis occurs).
When the beetles eat the potatoes, they rupture the membrane of the plastids and release this double stranded (ds) RNA into their guts. Protected thus far from degradation and incorporation into RISC (RNA Induced Silencing Complex) in the plant, the insect acquires this dsRNA and is free to bind the resulting shorter pieces and deactivate and destroy complementary strands of “sense” RNA that would otherwise code for proteins.
Normally, this RNA silencing would be fine for the insect, but the dsRNA that the scientists added is complementary to genes that are necessary for the potato beetle’s growth and survival. The beetles don’t all die from it, but they cannot grow from eating these potatoes: the potato became resistant to the most destructive pest around without anyone having to spray it or introduce any chemical. The cherry on top is that by targeting specific RNAs, the specificity of the pest control can literally be guaranteed and potential unintended matches could be located by running a BLAST on the inserted dsRNA sequence.
So far, this technique has been shown to work on potatoes and tomatoes, but has yet to be successfully applied to species like rice and corn. But since this technique is very new, I wouldn’t exclude this possibility (once they can figure out how to gain entry to the plastids in these grains).
The future of pest control might be chemical free, that is if the common person is able to understand that this technique is almost assuredly less risky than either organic or conventional pesticides. Unlike the “fungal” solution currently going viral , this really only impacts the desired species and mustn’t be “released,” shipped, or sprayed whatsoever.