Abstract
NOI10 and NOI11 are two RIN4-like/NOI proteins that participate in the immune response of the Arabidopsis plant and affect the RIN4-regulated mechanisms involving the R-proteins RPM1 and RPS2. The immune response in plants depends on the regulation of signaling pathways triggered by pathogens and herbivores. RIN4, a protein of the RIN4-like/NOI family, is considered to be a central immune signal in the interactions of plants and pathogens. In Arabidopsis thaliana, four of the 15 members of the RIN4-like/NOI family (NOI3, NOI5, NOI10, and NOI11) were induced in response to the plant herbivore Tetranychus urticae. While overexpressing NOI10 and NOI11 plants did not affect mite performance, opposite callose accumulation patterns were observed when compared to RIN4 overexpressing plants. In vitro and in vivo analyses demonstrated the interaction of NOI10 and NOI11 with the RIN4 interactors RPM1, RPS2, and RIPK, suggesting a role in the context of the RIN4-regulated immune response. Transient expression experiments in Nicotiana benthamiana evidenced that NOI10 and NOI11 differed from RIN4 in their functionality. Furthermore, overexpressing NOI10 and NOI11 plants had significant differences in susceptibility with WT and overexpressing RIN4 plants when challenged with Pseudomonas syringae bacteria expressing the AvrRpt2 or the AvrRpm1 effectors. These results demonstrate the participation of NOI10 and NOI11 in the RIN4-mediated pathway. Whereas RIN4 is considered a guardee protein, NOI10 and NOI11 could act as decoys to modulate the concerted activity of effectors and R-proteins.