Arabidopsis thaliana SOBER 1 ( SUPPRESSOR OF AVRBST ‐ ELICITED RESISTANCE 1) suppresses plant immunity triggered by multiple bacterial acetyltransferase effectors

Summary Plants evolved disease resistance (R) proteins that recognize corresponding pathogen effectors and activate effector‐triggered immunity ( ETI ). However, it is largely unknown why, in some cases, a suppressor of ETI exists in plants. Arabidopsis SOBER 1 (Suppressor of AvrBsT‐elicited Resistance 1) was identified previously as a suppressor of Xanthomonas acetyltransferase effector AvrBsT‐triggered immunity. Nevertheless, the extent to which SOBER 1 suppresses ETI is unclear. Here, we identified SOBER 1 as a suppressor of Pseudomonas acetyltransferase effector HopZ5‐triggered immunity in Arabidopsis using recombinant inbred lines. Further analysis showed that SOBER 1 suppresses immunity triggered by multiple bacterial acetyltransferases. Interestingly, SOBER 1 interferes with the immunity signalling activated by some but not all tested acetyltransferase effectors, indicating that SOBER 1 might target components that are shared between several ETI pathways.