On dark, starless, summer nights, sometimes we get surprised by steady lights emitted by click beetles or flashing lights from fireflies. Have you ever wondered why those lights liven up the sky? The lights are used to communicate, attract prey, defend, and mate. Maybe similar lights can be designed for plants to talk to insects to increase natural insect pollination rates of crops for food production.
Much like when fireflies talk to each other using flashing lights, maybe plants will “talk“ to insects in the near future. In fact, just last year, researchers at the University of Minnesota introduced a promising biological pathway in plants that could improve natural insect pollination of crops by causing plants to “glow.”
This glow is called bioluminescence and occurs naturally in many organisms, like vertebrates, invertebrates, fungi, and bacteria. One newsworthy example you may have heard of were the algae that gave a neon light show dancing over the waves off the coast of California last year.
In fireflies, the glowing lights come from an enzyme called luciferase. Luciferase is used in labs to detect genes that cause diseases, like COVID-19. One disadvantage though is that in order to light up, luciferase needs another chemical called luciferin and this can make the experiment quite pricey.
Arjun Khakhar and his team at the University of Minnesota developed a less pricey system that allows plants to glow using fungi bioluminescence. The pathway starts with caffeic acid ―commonly found in woody plants like coffee. The researchers turned caffeic acid into luciferin, the light emitting compound, causing the plant to glow. And they successfully introduced the new fungal bioluminescence pathway into plants like tobacco, tomatoes, and dahlias ― can you imagine your backyard garden or veggie plot glowing?
The team hopes that the system can be used as a way for plants to “talk” to insects using lights in a Morse code-like pattern to increase pollination of important crops ― insects pollinate about 30% of the food we eat ― like when fireflies use unique flashes to communicate and find a mate.
The findings can help with food security in this rapidly changing climate by enhancing the insect-plant relationship. In a few years those summer lights just may be coming from plants.
Citation: Khakhar, A., Starker, C. G., Chamness, J. C., Lee, N., Stokke, S., Wang, C., Swanson, R., Rizvi, F., Imaizumi, T., & Voytas, D. F. (2020). Building customizable auto-luminescent luciferase-based reporters in plants. eLife, 9, e52786.