Bacterial pathogen deploys the iminosugar glycosyrin to manipulate plant glycobiology

Nattapong Sanguankiattichai, Balakumaran Chandrasekar, Yuewen Sheng, Nathan Hardenbrook, Werner W. A. Tabak, Margit Drapal, Farnusch Kaschani, Clemens Grünwald-Gruber, Daniel Krahn, Pierre Buscaill, Suzuka Yamamoto, Atsushi Kato, Robert Nash, George Fleet, Richard Strasser, Paul D. Fraser, Markus Kaiser, Peijun Zhang , Gail M. Preston , and Renier A. L. van der Hoorn

Science 17 Apr 2025; Vol 388, Issue 6744 pp. 297-303; DOI: 10.1126/science.adp2433

Abstract

The extracellular space (apoplast) in plants is a key battleground during microbial infections. To avoid recognition, the bacterial model phytopathogen Pseudomonas syringae pv. tomato DC3000 produces glycosyrin. Glycosyrin inhibits the plant-secreted β-galactosidase BGAL1, which would otherwise initiate the release of immunogenic peptides from bacterial flagellin. Here, we report the structure, biosynthesis, and multifunctional roles of glycosyrin. High-resolution cryo–electron microscopy and chemical synthesis revealed that glycosyrin is an iminosugar with a five-membered pyrrolidine ring and a hydrated aldehyde that mimics monosaccharides. Glycosyrin biosynthesis was controlled by virulence regulators, and its production is common in bacteria and prevents flagellin recognition and alters the extracellular glycoproteome and metabolome of infected plants. These findings highlight a potentially wider role for glycobiology manipulation by plant pathogens across the plant kingdom.

See https://www.science.org/doi/10.1126/science.adp2433