Harnessing dTALE-secreting Pseudomonas syringae to unravel spatially orchestrated effector-triggered immunity

• Applicant: Dr. Haseong Kim
• Subject Area: Plant Breeding and Plant Pathology ; Plant Cell and Developmental Biology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 573337768

This project aims to dissect the spatial complexity of Effector-Triggered Immunity (ETI) in Arabidopsis using Pseudomonas syringae engineered to deliver synthetic transcription activator-like effectors (dTALEs). Traditional models of plant immunity, such as the Zigzag model, are being expanded to include spatial layers of response, where effector-targeted PRIMER cells and surrounding BYSTANDER cells form a localized defense zone. However, existing approaches cannot reliably distinguish plant cells in different infection states under native infection conditions. To overcome this, we developed a novel reporter system where dTALEs with customer-defined DNA specificity, delivered by P. syringae, drive the robust transcription of desired reporter genes. To best our knowledge, this is the first report of P. syringae delivering functional dTALEs, which enabled sensitive labeling of effector-receiving PRIMER cells, even at low bacterial loads and early timepoints. In addition, unlike other conventional reporter system, our dTALE based reporter can be easily integrated with transcriptomic analysis as our reporter also makes transcriptional footprints, which can be traced at single cell level. Our preliminary work confirms the delivery of TALEs to Arabidopsis via P. syringae, activation of desired endogenous target genes without generating transgenic plants, and enrichment of nuclei from PRIMER or non-PRIMER cells using Fluorescence-Activated Nuclei Sorting (FANS). The work programme proposed in this proposal includes three major steps: (1) generation of dTALE-inducible Arabidopsis reporter lines in wild-type and NLR knockout backgrounds, (2) identification of ETI marker genes specific to PRIMER and BYSTANDER cells using spatial transcriptomics and FANS/RNA-seq, and (3) functional analysis of these markers through promoter-reporter assays and targeted activation using dTALEs. This approach will reveal the spatial logic of ETI and provide powerful tools and resources for the plant immunity research community.

• DFG Programme: Position