Imagine that I could implant all the world’s medical knowledge into your head. You blink, and you instantly know every bit of anatomy, every surgical procedure, and every diagnostic criterion for every disease. You land a job in a hospital. And you suck. Despite your newfound skills, you still have no idea how hospitals work, how to talk to patients, or how to cooperate with your fellow doctors. Ill-suited and out-of-place, you quit.

The lesson behind this little vignette is that it takes social skills, as well as technical savvy, to succeed in a new job. And that’s a guideline that bacteria duly follow.

If you look at the roots of legumes, like peas or beans, you’ll find small swollen nodules. Each