Identification and characterization of two novel plant immune receptors, RLP23 and RLP32 and engineering immunity in crops
T. NÜRNBERGER (1), H. Böhm (1), I. Albert (1), L. Fan (1), E. Melzer (1), K. Fröhlich (1), W. Wan (1) (1) University Tübingen, Germany

Host pattern recognition receptor-mediated perception of microbe-associated molecular patterns (MAMP) is a prerequisite for the initiation of antimicrobial defenses in all multicellular organisms including plants. We report on the rapid identification of two novel pattern recognition receptors by exploiting the natural variation of PRRs within Arabidopsis ecotypes. A combination of GWAS and rad-seq genotyping was employed to identify novel pattern recognition receptors, RLP23 and RLP32, respectively, that contribute to immunity to microbial infection by sensing proteinaceous patterns from various microbes. RLP23 recognizes a peptide motif within necrosis-and-ethylene-inducing protein1 like proteins (NLPs). As NLPs occur in three microbial lineages (bacteria, fungi, oomycetes) this pattern shows a uniquely wide distribution among triggers of plant or metazoan immunity. RLP32 recognizes proteinaceous patterns found in Ralstonia solanacearum or Escherichia coli. Both receptors belong to the class of leucine rich-repeat (LRR) proteins lacking a cytoplasmic kinase domain. Both receptors constitutively interact with and require SOBIR1 as a co-receptor. Another co-receptor, BAK1, is recruited into the RLP/SOBIR1 complex in a ligand-dependent manner. The interaction of RLP23 and BAK1 is stabilized by the ligand in a way similar to that reported for FLS2 and BAK1. The novel PRRs are specific to Brassicaceae . Stable expression of RLP23 in tomato or potato conferred NLP recognition specificity to both plants and enhanced immunity to infection by NLP-producing oomycete (Phytophthora infestans) and fungal (Sclerotinia sclerotiorum) plant pathogens in RLP23-transgenic potato. Systematic comparison of plant immune signaling pathways and responses activated through LRR-RK-type PRR FLS2 (recognizes flg22) and LRR-RP-type PRR, RLP23 (recognizes NLP) has revealed that both receptor types activate similar, but not identical biological output patterns.

Abstract Number: C20-2
Session Type: Concurrent