ABSTRACT Pathogens deploy effector proteins to manipulate host physiology and promote infection. YopJ family effectors are highly conserved across bacterial genera that cause crop diseases. Nucleotide‐binding leucine‐rich repeat receptors (NLRs) play a central role in direct or indirect recognition of effectors and trigger immune responses, including hypersensitive cell death (HR). Two NLRs, Nicotiana benthamiana homologues of Pseudomonas tomato race 1 (NbPtr1) and HOPZ‐ACTIVATED RESISTANCE 1 (NbZAR1), were recently identified as independently recognising two YopJ family effectors, HopZ5 and AvrBsT/XopJ2. NbZAR1 also detects XopJ4 via the receptor‐like cytoplasmic kinase XOPJ4 IMMUNITY 2 (JIM2). Here, we conducted Agrobacterium ‐mediated transient expression assays with 20 YopJ family effectors from five phytopathogenic bacterial genera and identified 12 YopJ family effectors that are recognised either by NbZAR1 or independently by NbZAR1 and NbPtr1. Furthermore, we show that YopJ family effector‐induced HR is differentially suppressed by the deacetylase SUPPRESSOR OF AVRBST‐ELICITED RESISTANCE 1, suggesting more than one mechanism for YopJ family effector recognition. This work provides the genetic basis of the recognition of YopJ family effectors in N. benthamiana and lays a foundation for the mechanistic study of NbZAR1/JIM2 and NbPtr1 mode of activation.
Kim et al. (Sun,) studied this question.