To defend themselves, organisms must first identify the “enemy”. In plants, this process is particularly crucial, as they lack an adaptive immune system based on specialized immune cells like that of animals. Instead, they rely on a sophisticated surveillance system based on receptors anchored at the cell surface, capable of detecting danger signals originating from microorganisms or from damage to their own tissues.

A recent review takes an in-depth look at how these recognition mechanisms work, focusing on carbohydrate- or glycan-based signals. Fragments of these molecules, found both in microorganisms and in plant cell walls, act as true “alarm signals” that trigger defensive responses.

The study highlights that both plants and animals possess a wide diversity of cell-surface receptors that act as sentinels, selectively recognizing these signals. However, the molecular understanding of these processes is far more advanced in animals than in plants. Thanks to recent advances in structural biology, researchers at CBGP have been able to describe in detail how plant receptors interact with glycans, comparing these mechanisms with those in animals, where knowledge is more firmly established.

The findings indicate that, despite the presence of common structural elements and shared motifs, plants and animals have evolved distinct strategies to recognize these danger signals, reflecting their independent evolutionary trajectories.

“We believe that deciphering how plant Pattern Recognition Receptors (PRRs) bind to carbohydrates is a key step toward understanding fundamental mechanisms of immunity in eukaryotic organisms,” the authors note. They also highlight that integrating knowledge from both plant and animal systems helps identify shared principles as well as key differences in these processes.

Beyond fundamental knowledge, these advances open the door to practical applications. The use of glycans and their receptors could become a sustainable tool to enhance crop immunity and improve resistance to diseases, and essential goal for moving toward more efficient and environmentally friendly agricultural systems.