Longitudinal zone- and cell-type-specific immune responses sustain Arabidopsis roots against pathogen infections
The immunity is dynamically regulated to balance growth and defense. Roots consisting of diverse cell types across longitudinal developmental zones are vital for plant survival amidst most microbial challenges. Leveraging single-cell transcriptomics and imaging of Arabidopsis roots, here, we reveal that in contrast to microbe-associated molecular patterns (MAMPs), plant-derived phytocytokines elicit robust, coordinated immune responses across various root cell types and zones, ensuring the continuity of growth-defense trade-offs at the organismal level. The intensity of immune responses in different root zones tightly correlates with invasion sites of fungal and bacterial pathogens. Differential expression of receptors and key signaling modules in distinct cell types and zones dictates the response intensity to specific elicitors. Furthermore, motif-informed network inference identifies key transcriptional regulators targeting each root cell type, driving cell identity-based transcriptomic immune responses. Our findings reveal that distinct phytocytokines trigger potent and coordinated cell type- and stage-dependent transcriptional reprogramming. The contrasting availability of convergent signaling components and transcription regulators orchestrate cell-identity immune responses at the organ level. Overall design: Following different elicitors treatment, root cells from 7-day old root seedings were isolated by enzyme digestion and analyzed using the single-cell RNA-seq data.