Tracking calcium ions in sensitive plants

Abstract

The sensitive plant Mimosa pudica quickly folds its many leaflets when touched, burned, or wounded. But the mechanism behind how —and why—these plants swiftly turn demureisn’t clear. New research suggests that a flood of calcium ions kicks off the process to help these touch-me-not plants defend themselves against hungry insects ( Nat. Commun. 2022, DOI: 10.1038/s41467-022-34106-x ). “People think that plants are static, insensitive, kind of boring,” says Masatsugu Toyota, a plant physiologist at Saitama University. But plants can sense touch instantaneously, and the sensitive plant shows “fantastic movement” without having neurons, brains, or muscles, he says. Toyota, Mitsuyasu Hasebe of the National Institute for Basic Biology, and their colleagues wondered how sensitive plants send long-distance signals to trigger leaf folding. To look for clues, they engineered sensitive plants to produce a green fluorescent protein–based biosensor, which binds to Ca 2+ to reveal its presence in plants’ cells. Then the