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bioRxiv · 10.64898/2026.05.04.722566

Linking sugar sensing to immunity in plants via O-glycosylation

Aizezi, Y.·Bi, Y.·Zhang, H.·Kim, J.-G.·Chaudhary, A.·Trinh, C. S.·Shen, Q. J.·Xu, S.-L.·Mudgett, M. B.·Wang, Z.-Y.
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Abstract

Interaction with microbes can reprogram metabolism and alter nutrient availability in plant cells. How metabolic changes modulate immune responses remains unknown. Here, we show that sugar-sensing O-glycosylation of immune-signaling kinases mediates metabolic regulation of immunity. Under sugar-replete conditions, the MAP kinase kinases (MKK4 and MKK5), key components of pattern-triggered immunity (PTI), are glycosylated with O-GlcNAc and O-fucose on their activation loops, blocking their phosphorylation by upstream kinases and thereby restricting PTI. Pathogen infection or sugar starvation reduces O-glycosylation of MKK4/5 and enhances immune signaling; these effects are reversed by GDP-fucose treatment, demonstrating that reduced sugar availability decreases O-fucosylation and enhances immune signaling in infected cells. Chemical inhibition of O-fucosylation enhances immunity and pathogen resistance in both Arabidopsis and tomato. Our findings establish O-glycosylation of MKKs as a metabolic rheostat that fine-tunes immune responses according to sugar availability during plant-microbe interactions, providing a new strategy for improving crop health.

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Aizezi, Y., Bi, Y., Zhang, H., Kim, J.-G., Chaudhary, A., Trinh, C. S., Shen, Q. J., Xu, S.-L., Mudgett, M. B., Wang, Z.-Y.. 2026-05-07. Linking sugar sensing to immunity in plants via O-glycosylation. https://doi.org/10.64898/2026.05.04.722566

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