Expression analysis of EDS1-NLS

TIR-type nucleotide-binding leucine-rich repeat domain proteins (TNLs) constitute one major group of immune receptors in dicotyledonous plants. Under normal conditions, TNLs can detect non-self or modified-self within the plant cytoplasm to activate immune signaling characterized by extensive transcriptional reprogramming and efficiently counteracting pathogen infection. At the same time, TNLs, in negative epistatic interaction with a second endogeneous locus or allele are causal for induction of autoimmunity or hybrid necrosis. Both native, pathogen-induced TNL responses and autoimmunity are fully dependent on the plant-specific lipase-like protein EDS1, which is a central integrator for all TNL-mediated responses. EDS1 signals within structurally similar, but spatially distinct complexes with PAD4 and SAG101. We here analyzed stable transgenic lines expressing an EDS1 fusion with enforced nuclear localization. Even in absence of SAG101, nuclear-localized EDS1-PAD4 complexes are fully sufficient to function in basal and effector-triggered immunity. Furthermore, we show that nuclear EDS1, when expressed to high levels, can induce autoimmuity in combination with an RPP1-like gene cluster from ecotype Ler. RPP1-like genes are also implicated in several cases of hybrid necrosis, and we can identify the RPP1 paralog R8 as causal for autoimmunity induction by nuclear EDS1 and a previously characterized, EMS-induced mutation. This highlights the important role of EDS1-family proteins in the nuclear compartment in different immune-like responses.

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Stuttmann J, Peine N, Garcia AV, Wagner C, Choudhury SR, Wang Y, James GV, Griebel T, Alcázar R, Tsuda K, Schneeberger K, Parker JE