Nuclear translocation of ADR1s is required for a complete plant immunity

Plants utilize pattern recognition receptors (PRRs) and nucleotide-binding leucine-rich repeat receptors (NLRs) to detect pathogens and trigger immunity. ADR1s and NRG1s are two classes of helper NLRs, which are required for immunity activated by many sensor NLRs as well as some PRRs. The NLR ZAR1 recognizes the Xanthomonas campestris pv. campestris (Xcc) effector AvrAC and Pseudomonas syringae effector HopZ1a, oligomerizing to form a resistosome to trigger immunity. Previous studies showed that ADR1s and NRG1s are not required for HopZ1a-induced disease resistance. Here, we found that AvrAC-induced resistance against Xcc depends on ADR1s. The expression of defense genes induced by both AvrAC and HopZ1a is impaired in the adr1 triple mutant. Recognition of AvrAC and HopZ1a by ZAR1 induces the translocation of ADR1s into the nucleus, and this process depends on the nuclear localization signal of ADR1s but not on its P-loop. Transgenic complementation experiments revealed that the nuclear localization of ADR1-L1 is required for the activation of full resistance. In addition, we observed that PRRs and TNLs activation can also enhance the accumulation of ADR1s in the nucleus, indicating that the regulation of defense responses through nuclear translocation of ADR1s is a common mechanism downstream of different immune receptors.