This is a review of Carter, Helm et al. bioRxiv 374264; doi: https://doi.org/10.1101/374264 posted on July 23, 2018. In this paper, the authors showed that diverse barley cultivars are able to respond to the Pseudomonas syringae effector AvrPphB and they characterized  both the effector target (PBS1) and the receptor (PBR1) responsible for this recognition. Furthermore, their phylogenetic analyses revealed that the immune receptor involved in this response is not orthologous to a previously characterized receptor (RPS5) from Arabidopsis thaliana that has a functionally analogous AvrPphB recognition mechanism. This leads the authors to conclude that recognition of the AvrPphB protease has evolved independently in Arabidopsis and barley.