Arabidopsis thaliana SOBER1 (SUPPRESSOR OF AVRBST-ELICITED RESISTANCE 1) suppresses plant immunity triggered by multiple bacterial acetyltransferase effectors.

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 SOBER1 (Suppressor of AvrBsT-elicited Resistance 1) was identified previously as a suppressor of Xanthomonas acetyltransferase effector AvrBsT-triggered immunity. Nevertheless, the extent to which SOBER1 suppresses ETI is unclear. Here, we identified SOBER1 as a suppressor of Pseudomonas acetyltransferase effector HopZ5-triggered immunity in Arabidopsis using recombinant inbred lines. Further analysis showed that SOBER1 suppresses immunity triggered by multiple bacterial acetyltransferases. Interestingly, SOBER1 interferes with the immunity signalling activated by some but not all tested acetyltransferase effectors, indicating that SOBER1 might target components that are shared between several ETI pathways.