Pattern recognition receptors confer plant salt tolerance via WRKY18/WRKY40 transcription factors

Pattern recognition receptors (PRRs) bind microbe- and damage-associated molecular patterns (MAMPs/DAMPs, respectively) to enhance host immunity in animals and plants. Here, we report that PRRs also confer salt tolerance in the model plant following recognition of cognate ligands, such as bacterial flagellin and EF-Tu and the endogenous Pep peptides. Pattern-triggered salt tolerance (PTST) requires the PRR-associated kinases and , and the NADPH oxidase . Transcriptome profiling reveals an inventory of PTST target genes, which increase or acquire salt responsiveness following an exposure to immunogenic patterns. In their regulatory DNA sequences, specific binding sites for a subset of WRKY transcription factors are over-represented. Accordingly, PTST requires and , which activate salt tolerance-related genes but attenuate pathogen defense-related genes, including the immunity activator. PRR signaling leads to sustained WRKY40/WRKY18 accumulation under salt stress and utilizes both s for salt tolerance. The PRR-WRKY40/WRKY18 module also confers salt tolerance after challenge with non-pathogenic bacteria. Our findings give molecular insight into signaling plasticity underlying biotic-abiotic stress cross-tolerance in plants conferred by PRRs.