The Cyst Nematode SPRYSEC Protein RBP-1 Elicits Gpa2- and RanGAP2-Dependent Plant Cell Death

International audienceBiotrophic plant pathogens produce effector proteins that are delivered to the host cytoplasm where they alter defense responses and metabolism to favor pathogen colonization. In turn, plants have evolved intra-cellular proteins to recognize pathogen effector proteins, known as NB-LRR proteins, which are similar in structure to animal NOD-LRR immune receptors. While effector proteins recognized by NB-LRR proteins have been identified from many organisms, the identification of such proteins from metazoan plant parasites has presented unique challenges due to the lack of genetically tractable model species. The potato Gpa2 protein confers resistance to some isolates of the potato pale cyst nematode, Globodera pallida. In this report, we show that Gpa2 recognizes certain variants of the G. pallida protein, Gp-RBP-1, which is highly polymorphic both within and between populations. This recognition in turn induces defense responses, including a form of programmed cell death characteristic of plant immune receptor activation. Moreover, we show that a Gpa2-interacting protein, RanGAP2, is required for Gpa2 function and that activation of Gpa2 is enhanced when Gp-RBP-1 is artificially tethered to RanGAP2. Thus, our findings suggest that RanGAP2 acts as a recognition co-factor for Gpa2, and have important implications for our understanding of the mechanisms and evolution of pathogen recognition by NB-LRR protein