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.

This is a review of Caseys et al. bioRxiv doi: https://doi.org/10.1101/507491 posted on June 25, 2019. This study aims at addressing whether coevolutionary models of host-pathogen interactions apply to a generalist pathogen that exhibits quantitative virulence across a broad range of plants. They generated an exhaustive virulence matrix for the nectrophic fungus Botrytis cinerea on 90 genotypes of 8 plant species. They conclude that this pathosystem doesn’t fit traditional arms-race coevolution models with quantitative variation in susceptibility distinct from the phylogenetic relationships between the examined plants.

This is a review of Baudin, Schreiber, Martin et al. bioRxiv doi: https://doi.org/10.1101/592824 posted on March 29, 2019. The authors used structural modelling to identify elements required for self-association of the NLR immune receptor ZAR1, specifically its N-terminal CC-domain ZAR1CC. They discovered that the N-terminal α1 helix and EDVID motif in ZAR1CC are important for oligomerization and function of ZAR1. This complements recent findings by Wang et al. (2019) based on cryo-EM structures, highlighting the importance of the α1 helix for the activity of ZAR1 although some differences were noted that could reflect the different experimental set ups (CC domain vs full-length protein) as discussed in the paper.

This is a review of Knaus et al. bioRxiv doi: https://doi.org/10.1101/633701 posted on May 16, 2019. In this paper, the authors studied variations in ploidy in a wide range of isolates of the potato blight pathogen Phytophthora infestans.

This is a review of Maekawa et al. bioRxiv 293050; doi: https://doi.org/10.1101/352278 posted on June 20, 2018. In this paper, the authors mined the transcriptomes of 50 different accession of wild barley, generating a rich library of natural variants of the MLA immune receptor—a classical nucleotide-binding domain and leucine-rich repeat-containing (NLR) protein. They grouped the MLA variants in two subfamilies with all receptors known to be effective against the powdery mildew fungus grouping in one subfamily.