Context
Pesticides have been used to protect crops for over 4,500 years, dating back to 2500 BCE when ancient Sumerians applied sulfur to control pests [4]. Their use expanded rapidly during the Green Revolution of the mid-20th century, when advances in agricultural technology helped boost food production worldwide [4]. Modern pesticides control insects, weeds, fungi, and other harmful organisms by disrupting biological processes essential for their survival and reproduction.
The Pesticide Treadmill
While pesticides remain essential tools for protecting crops, their increasing use has raised concerns about resistance development and environmental sustainability.
In 2010, global pesticide use totaled approximately 2.5 million metric tons (5.6 billion pounds) [1]. By 2023, that figure had risen to 4.3 million metric tons (9.5 billion pounds), reflecting a substantial increase in worldwide pesticide application [2].
However, this growth has been accompanied by significant challenges. Excessive pesticide use creates strong selective pressure on pest populations, accelerating the development of insect resistance. As resistant pests become more prevalent, farmers often rely on increasingly frequent applications or more potent chemicals to maintain effectiveness, creating an escalating arms race between agricultural pests and pest-control strategies.
Beyond resistance, synthetic pesticides can also have unintended ecological consequences. While effective at controlling agricultural pests, they may affect non-target organisms such as pollinators, beneficial insects, birds, and aquatic species [4]. Some synthetic pesticides persist in the environment, allowing them to accumulate in soil and water, disrupt ecosystem functions, reduce biodiversity, and contribute to contamination of nearby waterways through runoff [4].
E. coli as an Inducible Pesticide Dispenser
Our proposed solution is an inducible pesticide release system using phyllospheric bacteria as our ideal chassis. For proof of concept, we are usingE. coli as our model chassis. Rather than spraying pesticides continuously, our system will release a natural pesticide only when in stress conditions, like when a plant encounters pests.
To achieve this, we are engineeringE. coli to respond to methyl salicylate (MeSA) by producing a natural pesticide called Vegetative insecticidal protein (Vip3A). MeSA is a volatile organic compound that plants release to enhance their defenses against pests. Our bacteria will detect MeSA and convert it into salicylic acid, which will then induce production of the pesticide. To prevent unintended environmental spread of our GMO, we will incorporate a kill switch that eliminates the bacteria in the absence of theophylline, a molecule produced by plants. This ensures that the bacteria can survive only while associated with plant hosts.
Our Natural Pesticide
Once induced by salicylic acid, the natural pesticide that our chassis will produce and release is Vip3A. Vip3A, a protein primarily derived from Bacillus thuringiensis, is a natural pesticide that is highly effective against lepidopteran pests [3]. As assessed by the US Environmental Protection Agency, Vip3A does not negatively impact non-target organisms and is safe for human consumption, serving as an environmentally safe alternative to current synthetic options [5].
Support Us
You can support the UR iGEM 2026 team as a sponsor! Sponsors are vital to our research and presentation at the competition. Sponsorships can come in the form of financial support or in-kind gifts, including laboratory equipment, reagents, and other products that can aid our project.
Benefits of sponsoring us can include, but are not limited to: Your logo on our website, social platforms, team merchandise, iGEM presentation, and any other promotional materials.
References
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