Salicylic acid-triggered apoplastic proteolysis releases cryptic phytocytokines with distinct immunogenic functions
- 1University of Cologne
Abstract
Plants rely on an innate immune system to defend against pathogens through various molecular responses. In addition to classical damage- and pathogen-associated molecular patterns (DAMPs and PAMPs), plants produce endogenous signaling peptides termed phytocytokines that amplify and regulate immune responses following stress. Although most characterized phytocytokines originate from dedicated precursor proteins, the contribution of multifunctional proteins to phytocytokine generation remains poorly understood. Here, we show that salicylic acid (SA) rapidly remodels the maize apoplastic peptidome through an early, transient proteolytic program driven by apoplastic serine hydrolases. Time course peptidomics identified fourteen candidate phytocytokines, including two cryptic peptides, PC13 and PC14, released from the stress-associated zinc-finger protein ZmSAP7 and the migration inhibitory factor-like protein ZmMDL1, respectively. Both peptides activated immune-associated gene expression but triggered distinct transcriptional responses and exerted opposing effects on Ustilago maydis infection, with PC13 enhancing resistance and PC14 promoting susceptibility. Biochemical analysis demonstrated that PMSF-sensitive apoplastic serine proteases directly process ZmMDL1 to release PC14. Together, our findings uncover a SA-responsive proteolytic pathway that generates functionally distinct phytocytokines from multifunctional proteins, expanding the repertoire of immune signaling peptides and revealing an additional layer of regulation in plant defense.
Related
- Distinct root apoplastic barrier distribution and conserved peroxidase function in desert trees
- Matrilysin (MMP-7) Restricts RSV Infection and Airway Inflammation through Proteolysis of CCR3 and RSV-G
- Calcium-dependent proteolysis of the chimeric androglobin reveals altered localization of its isolated globin domain
- Calcium and autophagy connect photorespiratory oxidative signals with salicylic acid-mediated defense.
- Calendula officinalis medicinal value under saline-stress and salicylic acid treatment
BibTeX
@misc{katzy2026salicylic,
title = {{Salicylic acid-triggered apoplastic proteolysis releases cryptic phytocytokines with distinct immunogenic functions}},
author = {P. Katzy and H. Laia and Z. Zick and J. C. Misas Villamil and G. Doehlemann},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.01.748544},
url = {https://www.biorxiv.org/content/10.64898/2026.09.01.748544v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Salicylic acid-triggered apoplastic proteolysis releases cryptic phytocytokines with distinct immunogenic functions
AU - P. Katzy
AU - H. Laia
AU - Z. Zick
AU - J. C. Misas Villamil
AU - G. Doehlemann
PY - 2026
DA - 2026/09/01
PB - bioRxiv
DO - 10.64898/2026.09.01.748544
UR - https://www.biorxiv.org/content/10.64898/2026.09.01.748544v1
AB - Plants rely on an innate immune system to defend against pathogens through various molecular responses. In addition to classical damage- and pathogen-associated molecular patterns (DAMPs and PAMPs), plants produce endogenous signaling peptides termed phytocytokines that amplify and regulate immune responses following stress. Although most characterized phytocytokines originate from dedicated precursor proteins, the contribution of multifunctional proteins to phytocytokine generation remains poorly understood. Here, we show that salicylic acid (SA) rapidly remodels the maize apoplastic peptidome through an early, transient proteolytic program driven by apoplastic serine hydrolases. Time course peptidomics identified fourteen candidate phytocytokines, including two cryptic peptides, PC13 and PC14, released from the stress-associated zinc-finger protein ZmSAP7 and the migration inhibitory factor-like protein ZmMDL1, respectively. Both peptides activated immune-associated gene expression but triggered distinct transcriptional responses and exerted opposing effects on Ustilago maydis infection, with PC13 enhancing resistance and PC14 promoting susceptibility. Biochemical analysis demonstrated that PMSF-sensitive apoplastic serine proteases directly process ZmMDL1 to release PC14. Together, our findings uncover a SA-responsive proteolytic pathway that generates functionally distinct phytocytokines from multifunctional proteins, expanding the repertoire of immune signaling peptides and revealing an additional layer of regulation in plant defense.
ER -