Spatially staged SAR features immune microdomains
Year: 2027
Type: dataset
Abstract: Systemic acquired resistance (SAR) enables uninfected plant tissues to acquire enhanced defensive capacity after local pathogen perception, yet how long-distance immune information is spatially interpreted in distal organs remains poorly understood. Here, we induced effector-triggered immunity (ETI)-associated SAR in Arabidopsis thaliana by local infection with Pseudomonas syringae pv. tomato DC3000 carrying avrRPM1 and integrated temporal bulk RNA-seq, single-nucleus RNA-seq, Stereo-seq spatial transcriptomics, and multiplex RNA in situ hybridization to resolve systemic immune activation across time, cell identity, and anatomical space. We show that distal systemic immunity is not initiated as a uniform whole-leaf response. Instead, single-nucleus analysis identifies a distinct mesophyll cell substate in distal leaves at 24 hours post local infection, characterized by the coordinated induction of immune receptors, endoplasmic reticulum (ER) stress/protein-folding machinery, and a jasmonic acid (JA) response signature. Pseudotime trajectory analysis positions this early immune-competent mesophyll state prior to broader SARD1/CBP60g-associated salicylic acid (SA) and N-hydroxypipecolic acid (NHP) defense amplification. Spatially, Stereo-seq and high-resolution multiplex RNA in situ hybridization reveal that this early immune program is selectively confined to multicellular vascular-proximal microdomains surrounding lateral veins. Notably, activation of prominent vascular-proximal markers is detectable in rare perivascular cells as early as 4 hours post-infection. Together, these findings support a spatially staged model of ETI-induced SAR, wherein systemic signals are initially decoded in localized vascular-proximal microdomains along lateral veins before being relayed into broader, tissue-wide SA/NHP defense programs.
Authors: Xia, Yiji, Zhang, Bingxu
Institution: Hong Kong Baptist University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7212356309