Acyl hydrolase that triggers the leaf senescence onset. Can use triolein as substrate to produce oleic acids. Involved in the EDS1-dependent intrinsic and indispensable resistance signaling pathway; together with PAD4, required for programmed cell death triggered by RPS4 in response to avirulent pathogens (e.g. P.syringae pv. tomato strain DC3000 and H.parasitica isolates CALA2 and EMWA1) and in restricting the growth of virulent pathogens (e.g. H.parasitica isolates NOCO2 and P.syringae pv. tomato strain DC3000 avrRps4). Contributes in reinforcing the immune response around hypersensitive response foci (PubMed:21434927). Regulates the nuclear localization of EDS1. Essential for the RPP8/HRT-mediated resistance to the turnip crinkle virus (TCV). Involved in the post-invasion resistance to P.pachyrhizi in the mesophyll. a carboxylic ester + H2O = a carboxylate + an alcohol + H(+) Part of a nuclear complex made of EDS1, PAD4 and SAG101, that can be redirected to the cytoplasm in the presence of an extranuclear form of EDS1 (PubMed:22072959). Interacts directly with EDS1. Can move to the cytoplasm when in complex with PAD4 and EDS1. Additional isoforms seem to exist. Expressed in senescing leaves. Not expressed until the onset of senescence in leaves. Specifically induced during senescence via a complex epigenetic processe involving histone methylation. Delayed onset of leaf senescence (about 4 days later). Reduced resistance to both virulent and avirulent pathogens (Pseudomonas syringae pv. tomato and Hyaloperonospora parasitica).