Divergent evolution of potato immune receptor CC domain interactions with the Ran GTPase-activating protein 2.

Effector-triggered immunity mediated by immune receptors in plants provides powerful defense against specific pathogens. Solanum tuberosum Ran GTPase-Activating Protein 2 (StRanGAP2) interacts with immune receptors Rx and Gpa2 through their coiled-coil (CC) domains. We assayed additional CC domains from other Solanaceous immune receptors and observed interaction by co-immunoprecipitation between StRanGAP2 and a novel immune receptor, STR5. A CC domain very similar to Rx and Gpa2, STR4, failed to interact, likely due to sequence divergence in the region implicated in StRanGAP2 binding. Like Rx and Gpa2, STR5 interacted with the StRanGAP2 N-terminal WPP domain. Our findings substantiate the importance of RanGAPs as common CC-interacting proteins of multiple immune receptors requiring further study to define their roles in pathogen perception.