Andee Wallace

Every year, millions of tons of pesticides are used in agriculture, globally. These chemicals, which cost tens of billions of dollars to produce, protect plants, but they also cause pollution and harm biodiversity. And they don’t offer full protection: “[Growers] still expect to lose 20% to 40% of their crops to pests and disease,” says Andee Wallace, 33. She’s developing an alternative: engineered microbes that can provide tailored crop protection without the downsides of chemical pesticides.

While earning a PhD at MIT, Wallace worked to understand how tiny marine creatures called diatoms create miniature glass structures. She also began growing vegetables and nurturing plants at her apartment. She became fascinated by their microscopic ecosystems; microbes cover every leaf, root, and petal, and they help plants process nutrients and protect them from disease. What if these microbes could be engineered to provide all the benefits of chemical pesticides, she thought, but without the drawbacks?

Wallace cofounded her company, Robigo, to pursue this idea. Robigo’s first target was a bacterium that causes disease in tomato plants. To tackle it, Wallace’s team started with a microbe commonly found on plants. They developed a CRISPR system that cuts a key region of DNA in the harmful bacteria, effectively killing them, then engineered the system into the microbes, which can then be applied to tomato plants. Because microbes commonly share DNA with their neighbors, the engineered ones should be able to pass the CRISPR system to harmful bacteria, triggering their destruction.

In an early, unpublished test on tomato plants treated with the engineered microbes, the plants grew 15% to 20% taller than untreated ones and showed a 90% reduction in symptoms of disease. An early field trial was less promising, failing to show any benefit, but Wallace is undeterred. “I think the fact that we were able to get our microbes into a field and run a trial is really a huge milestone for the company … and for the field of synthetic biology,” she says.