A chance observation about warts on a pea plant led a group of teenagers on a three-year mission to ease the world food crisis using agricultural science. Their perseverance paid off when they won the Grand Prize at the annual Google Science Fair in Palo Alto, Calif., in September. (Scientific American co-sponsors the awards.)

The mission started after Émer Hickey, a now 17-year-old from Kinsale, Ireland, and her mother first embarked on gardening a few years ago. They pulled up a pea plant and saw that the roots were covered in nodules. Thinking the bumps might be a sign of poor health, Emer brought the plant to her science teacher. He explained that the growths held rhizobium, a beneficial bacterium that converts nitrogen in the atmosphere into ammonia and other compounds that help plants grow.

At the time, Hickey's geography class was studying the world food crisis, which inspired her and two friends, Ciara Judge and Sophie Healy-Thow, to try and apply rhizobia to barley and oats to see if the microbes might boost their yields. “We became really interested in what this bacterium can do,” Healy-Thow says.

After some 120 tests on thousands of seeds in a bedroom-turned-laboratory, the team found that rhizobia sped up the rate at which barley seeds germinate by 50 percent and increased crop yield by as much as 74 percent.

They are now working with crop scientists to better understand how the bacteria interact with cereal crops and to confirm their results in broader field trials. Says Hickey: “We want to bring this into commercial use and change the world with our findings.”