bioRxiv · 2026-06-06
Scientists discovered that plants don't just sense the immune hormone salicylic acid inside their cells — they can also detect it outside cells using surface receptors, triggering defenses against pathogens through a newly identified signaling pathway.
Two plasma membrane receptor proteins (LecRK-I.8 and LecRK-VI.2) in Arabidopsis bind extracellular salicylic acid with micromolar affinity, suggesting a direct cell-surface perception mechanism
Mutagenesis of a computationally predicted binding pocket in LecRK-VI.2 abolished both salicylic acid binding and immune function, providing causal evidence for receptor-mediated signaling
Plants lacking these LecRK receptors showed impaired salicylic acid-induced resistance, altered gene expression programs, and reduced phosphoproteomic responses, confirming their role in downstream immune activation
