Abstract
The plant cuticle is often considered a passive barrier from the environment. We show that the cuticle regulates active transport of the defense hormone salicylic acid (SA). SA, an important regulator of systemic acquired resistance (SAR), is preferentially transported from pathogen-infected to uninfected parts via the apoplast. Apoplastic accumulation of SA, which precedes its accumulation in the cytosol, is driven by the pH gradient and deprotonation of SA. In cuticle-defective mutants, increased transpiration and reduced water potential preferentially routes SA to cuticle wax rather than to the apoplast. This results in defective long-distance transport of SA, which in turn impairs distal accumulation of the SAR-inducer pipecolic acid. High humidity reduces transpiration to restore systemic SA transport and, thereby, SAR in cuticle-defective mutants. Together, our results demonstrate that long-distance mobility of SA is essential for SAR and that partitioning of SA between the symplast and cuticle is regulated by transpiration.
| Original language | English |
|---|---|
| Article number | eaaz0478 |
| Journal | Science advances |
| Volume | 6 |
| Issue number | 19 |
| DOIs | |
| State | Published - May 2020 |
Bibliographical note
Funding Information:We thank J. Li for mod1 seeds, D. Klessig for ∝-PR-1 antibody, and R.-D. Jeong for help with transmission electron microscopy. We thank S. Wolf and R. Jetter for advice, J. Johnson for help with analytical analysis, and W. Havens and A. Crume for technical help. This work was supported by grants from National Science Foundation (MCB#0421914 and IOS#051909), Kentucky Science and Engineering Foundation (#1244), Kentucky Soybean Board (3084113467), and USDA National Institute of Food and Agriculture (Hatch project 1014539).
Publisher Copyright:
Copyright © 2020 The Authors,
ASJC Scopus subject areas
- General