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Title: Ptr1 and ZAR1 immune receptors confer overlapping and distinct bacterial pathogen effector specificities

Some nucleotide‐binding and leucine‐rich repeat receptors (NLRs) indirectly detect pathogen effectors by monitoring their host targets. InArabidopsis thaliana, RIN4 is targeted by multiple sequence‐unrelated effectors and activates immune responses mediated by RPM1 and RPS2. These effectors trigger cell death inNicotiana benthamiana, but the corresponding NLRs have yet not been identified. To identifyN. benthamianaNLRs (NbNLRs) that recognize Arabidopsis RIN4‐targeting effectors, we conducted a rapid reverse genetic screen using an NbNLR VIGS library.

We identified that theN. benthamianahomolog of Ptr1 (Pseudomonas tomato race 1) recognizes thePseudomonaseffectors AvrRpt2, AvrRpm1, and AvrB.

We demonstrated that recognition of theXanthomonaseffector AvrBsT and thePseudomonaseffector HopZ5 is conferred independently by theN. benthamianahomolog of Ptr1 and ZAR1. Interestingly, the recognition of HopZ5 and AvrBsT is contributed unequally by Ptr1 and ZAR1 inN. benthamianaandCapsicum annuum. In addition, we showed that the RLCK XII family protein JIM2 is required for the NbZAR1‐dependent recognition of AvrBsT and HopZ5.

The recognition of sequence‐unrelated effectors by NbPtr1 and NbZAR1 provides an additional example of convergently evolved effector recognition. Identification of key components involved in Ptr1 and ZAR1‐mediated immunity could reveal unique mechanisms of expanded effector recognition.

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Publisher / Repository:
Date Published:
Journal Name:
New Phytologist
Page Range / eLocation ID:
p. 1935-1953
Medium: X
Sponsoring Org:
National Science Foundation
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