An uORF-encoded mobile peptide sparks systemic stomatal immunity
Summary
Higher organisms spread external stimuli from the perceptive tissues to the whole body to achieve systemic responses. In plants, guard cells sense pathogens and close stomata to prevent their entry. We observed that pathogen-infected local leaves transmit the danger status to uninfected distal systemic leaves and trigger their stomatal closure as a global defense termed systemic stomatal immunity (SSIM). The underlying mobile signals remain unknown. Here, we report that an upstream open re
Content
# An uORF-encoded mobile peptide sparks systemic stomatal immunity
*Published: 2026 Mar 5*
Higher organisms spread external stimuli from the perceptive tissues to the
whole body to achieve systemic responses. In plants, guard cells sense pathogens
and close stomata to prevent their entry. We observed that pathogen-infected
local leaves transmit the danger status to uninfected distal systemic leaves and
trigger their stomatal closure as a global defense termed systemic stomatal
immunity (SSIM). The underlying mobile signals remain unknown. Here, we report
that an upstream open reading frame (uORF)-encoded systemic stomatal immune
conductor (USIC) acts as a long-distance mobile peptide inducing SSIM. In local
leaves, USIC increases upon pathogen/pattern signals and is secreted into the
apoplast for long-distance transport. In systemic leaves, USIC is perceived by
the cell surface SUCROSE-INDUCED RECEPTOR KINASE 1 (SIRK1)-KINASE 7 (KIN7)
receptor complex and induces METACASPASE 4 (MC4)-mediated KIN7 cleavage. KIN7
associates with proton pumps/aquaporins to regulate stomatal closure. This study
reveals a systemic signaling mechanism whereby an uORF-encoded mobile signal and
its receptor pathway activate SSIM.
DOI: 10.1016/j.cell.2025.12.024