Pathogen-associated molecular patterns ( PAMPs) are detected by plant pattern recognition receptors ( PRRs), which gives rise to PAMP-triggered immunity ( PTI). We characterized a novel fungal PAMP, Cell Death Inducing 1 (Rc CDI1), identified in the Rhynchosporium commune transcriptome sampled at an early stage of barley ( Hordeum vulgare) infection., The ability of Rc CDI1 and its homologues from different fungal species to induce cell death in Nicotiana benthamiana was tested following agroinfiltration or infiltration of recombinant proteins produced by Pichia pastoris. Virus-induced gene silencing ( VIGS) and transient expression of Phytophthora infestans effectors Pi AVR3a and Pex RD2 were used to assess the involvement of known components of PTI in N. benthamiana responses to Rc CDI1., Rc CDI1 was highly upregulated early during barley colonization with R. commune. Rc CDI1 and its homologues from different fungal species, including Zymoseptoria tritici, Magnaporthe oryzae and Neurospora crassa, exhibited PAMP activity, inducing cell death in Solanaceae but not in other families of dicots or monocots. Rc CDI1-triggered cell death was shown to require N. benthamiana Brassinosteroid insensitive 1-Associated Kinase 1 (NbBAK1), N. benthamiana suppressor of BIR1-1 (NbSOBIR1) and N. benthamiana SGT1 (NbSGT1), but was not suppressed by Pi AVR3a or Pex RD2., We report the identification of a novel Ascomycete PAMP, Rc CDI1, recognized by Solanaceae but not by monocots, which activates cell death through a pathway that is distinct from that triggered by the oomycete PAMP INF1. [ABSTRACT FROM AUTHOR]