The cells of all organisms are sugarcoated with polysaccharides, glycoproteins, and glycolipids. In multicellular organisms these polymers not only have a structural role in the organization of tissues and organs, but also have signaling activities. In the animal extracellular matrix for instance, the negatively charged hyaluronic acid (HA) polymers contribute to morphogenesis through mechanosensing, whereas HA fragments that are released from the polymer under certain conditions trigger inflammatory responses and angiogenesis (1). In plants, pectins are the major charged polysaccharides in the cell wall and thus can be considered the equivalent of HA. In addition, pectin-derived oligosaccharides released from the host cell wall during pathogen infection have been shown to trigger immune responses (2⇓–4). Gallego-Giraldo et al. (5) in PNAS now provide evidence for a role of pectin oligosaccharide signaling also in the response of plant cells to cell wall perturbation.