Great question! I study a partnership that some plants make with bacteria, called nodulation. Specifically, I’m interested in the way nodulation evolved, since most plants do everything they can to keep bacteria away.
Several different families of plants all evolved nodulation independently, kind of like how birds, bats, and insects all evolved wings independently. I want to know just how similar nodulation is in all the different families that do it, because that will give us clues about how it evolved. So I infect plants with their partner bacteria, and then I collect the plant roots and see which genes are being turned on and off as the plant welcomes in the bacteria. I can then compare those genes to the genes that other plants (that evolved nodulation independently) turn on when they’re nodulating. That way I can see if nodulation is the same or different in the different plant lineages, at a genetic level!