Convergent evolution of effector protease recognition by Arabidopsis and barley (bioRxiv)

Pathogenic bacteria Pseudomonas syringae produce an effector protein, AvrPphB. The indirect interaction between this bacterial effector and the Arabidopsis resistance (R) protein RPS5 has been characterized previously; AvrPphB is a cysteine protease that targets another plant protein, PBS1, causing it to activate RPS5. Carter and Helm et al. now show that the bacterial effector similarly elicits defense responses in barley, through a barley ortholog of PBS1. Interestingly though, the barley resistance protein, (Pbr1) is not an ortholos of the corresponding Arabidopsis R protein RPB5, indicating convergent evolution of this indirect recognition. The authors conclude that “selection to guard PBS1-like proteins is ancient. Also, the results suggest that PBS1-based decoys may be used to engineer protease effector recognition-based resistance in barley and wheat.” (Summary by Mary Williams)  bioRxiv 10.1101/374264