How Plants Talk to Themselves to Stop Stealing Too Many Nutrients

Plants can be sneaky, stealing nutrients from other plants. They do this through special structures called haustoria. These haustoria act like straws, sucking up nutrients from the host plant. But how do these parasitic plants know when to stop making more haustoria? It turns out, they have a clever way to communicate with themselves. Two plants, Phtheirospermum japonicum and Parentucellia viscosa, show us how this works. When these plants have already made some haustoria, they somehow tell the rest of the plant to stop making more. This isn't just about having enough nutrients; it's about balance. If a plant makes too many haustoria, it could kill the host plant and starve itself. Scientists found that when a haustorium matures, it sends out a signal. This signal travels through the plant, telling other parts to hold off on making new haustoria. It's like a plant version of a traffic light, telling the roots to stop making more haustoria.The signal involves a hormone called cytokinin. When a haustorium forms, it increases the amount of cytokinin in the plant. This increase tells the plant to stop making more haustoria, both near the existing ones and even far away. It's a clever way to make sure the plant doesn't overdo it and harm its host. To test this, scientists did some experiments. They added cytokinin to the plants and saw that it stopped new haustoria from forming. They also made the plants produce an enzyme that breaks down cytokinin. This made the plants keep making more haustoria, showing that cytokinin is key to this process. So, what's the big picture? Parasitic plants have a built-in system to regulate how many haustoria they make. This system uses cytokinin as a signal to stop making more haustoria. It's a smart way for plants to balance their nutrient needs without killing their hosts. This discovery could help us understand more about how plants communicate with themselves and maybe even find new ways to control parasitic plants. But here's a question to think about: If plants can communicate with themselves to regulate their behavior, could other organisms do the same? And if so, how might this knowledge help us understand and control pests and diseases?