RIN13-mediated disease resistance depends on the SNC1-EDS1/PAD4 signaling pathway in Arabidopsis.

ABSTRACT

Plants have evolved an innate immune system to protect themselves from pathogen invasion with the help of intracellular nucleotide-binding leucine-rich repeat (NLR) receptors, though the mechanisms remain largely undefined. RIN13 (RPM1-interacting protein 13) was previously reported to enhance disease resistance, and suppress RPM1 (a CNL-type NLR)-mediated hypersensitive response in Arabidopsis via an as yet unknown mechanism. Here, we show that RIN13 is a nuclear-localized protein, and functions therein. Overexpression of RIN13 leads to autoimmunity with high accumulation of salicylic acid (SA), constitutive expression of pathogenesis-related genes, enhanced resistance to a virulent pathogen, and dwarfism. In addition, genetic and transcriptome analyses show that SA-dependent and SA-independent pathways are both required for RIN13-mediated disease resistance, with the EDS1/PAD4 complex as an integration point. RIN13-induced dwarfism was rescued completely by either the pad4-1 or the eds1-2 mutant but partially by snc1-r1, a mutant of the TNL gene SNC1, suggesting the involvement of EDS1/PAD4 and SNC1 in RIN13 functioning. Furthermore, transient expression assays indicated that RIN13 promotes the nuclear accumulation of PAD4. Collectively, our study uncovered a signaling pathway whereby SNC1 and EDS1/PAD4 act together to modulate RIN13-triggered plant defense responses.