Comparative analysis of PAD4 and SAG101 interactors upon activation of NLR immunity in Arabidopsis thaliana

Intracellular NLR receptors with a central nucleotide-binding domain allow plants to detect specific pathogen-secreted proteins and initiate immune signaling. A family of conserved Enhanced disease susceptibility 1 proteins with a lipase-like and the EP domain transduces the signal from activated NLRs downstream. This family includes EDS1, PAD4 and SAG101 that form mutually exclusive heterodimers EDS1-PAD4 and EDS1-SAG101. Despite sequence similarities, PAD4 and SAG101 control different aspects of NLR immune signaling. More specifically, PAD4 and SAG101 regulate resistance and cell death outputs of the NLR receptor pair RRS1-RPS4, respectively. Also, PAD4 and SAG101 genetically cooperate with distinct downstream signaling NLRs - ADR1 and NRG1. The main aim of this IP-LC/MS project is to assess whether PAD4 and SAG101 form complexes with ADR1 and NRG1 and to gain insight into mechanisms of the genetically established functional links between EDS1 family proteins and downstream signaling NLRs.