When you're a newly sprouted corn seedling, all alone in the dirt, you need any advantage you can get. After all, you can't pick up your roots and travel to find resources or avoid pests. That's why corn plants emit toxic chemicals that keep away hungry insects aboveground and harmful microbes below. But to at least one kind of bacteria, this poison is more of a beacon. They follow the toxic trail back to the corn plant, set up camp in its roots, and help the vulnerable seedling grow.