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Poster

Session: Session 1 Presenting Authors at Posters (Odds)

P-077 - Robust activation of lettuce immunity via a cell surface immune receptor

Monday, July 14, 2025
13:30 - 15:15  
Location: Confex Hall 3
Extracellular & Intracellular non-self recognition & signaling

Necrosis- and ethylene-inducing peptide 1-like proteins (NLPs) are present in microbes from three different kingdoms of life. A short, conserved region of 24 residues from NLP3 of the Arabidopsis downy mildew (nlp24) acts as an immunity-triggering pattern (PAMP) in multiple plant species, including lettuce. No receptors for nlp24 (or other PAMPs) have yet been identified in lettuce or any other Asteraceae species. The lettuce reference genome does not have an ortholog of the Arabidopsis nlp24 receptor RLP23. Besides, the recognition specificity of the two plant species is different suggesting NLP recognition arose by convergent evolution. We performed an extensive characterization of early and late nlp24 recognition signaling outputs in lettuce, confirming it as a potent activator of immunity. Our PAMP time-course RNAseq experiment with nlp24 identified candidate transcriptional regulators of PAMP-triggered immunity. By combining association mapping, comparative genomics, and genetic complementation assays, we identified a cell surface immune receptor, different from RLP23, to be responsible for nlp24 recognition in lettuce. Analysis of nlp24 variants revealed the NLP regions required for the timely and robust activation of lettuce immunity. Overall, our research identified the first cell surface immune receptor in lettuce and provided evidence that activation of the cell surface immunity signaling by a PAMP is a quantitative rather than an all-or-nothing response.