Glycosidase and glycan polymorphism control hydrolytic release of immunogenic flagellin peptides

Glycosylation goes back and forth Plants produce receptors that recognize fragments of microbial flagellin, thus monitoring for infection by bacteria. Buscaill et al. studied how a flagellin fragment is made accessible for recognition by host glycosidases, which degrade the glycosylations shielding the peptide that triggers the immune response. The pathogen, in turn, evades detection by altering flagellin glycosylation and inhibiting the host glycosidase. This aspect of plant defense against infection plays out in the apoplast, the extracellular space within plant tissues. Science , this issue p. eaav0748