Fig. 3: Subtilase-inhibitor Epi1 suppresses processing of Qps, flg22 and flagellin.
From: Subtilase SBT5.2 inactivates flagellin immunogenicity in the plant apoplast
a Subtilase inhibitor, Epi1 suppresses the processing of all quenched peptides (QPs). Apoplastic fluids (AFs) isolated from N. benthamiana leaves transiently expressing protease inhibitors Epi1, SlCys8 and HsTIMP were mixed with QPs and fluorescence and were immediately monitored using a plate. QP processing in the empty vector (EV) control was set at 100% for each QP. Bars represent mean, and error bars represent ± SE of n = 3 biological replicates (i.e., AFs from 3 plants). Two-sided Students t test: *p < 0.05; **p < 0.01; ***p < 0.001. b Epi1 increases the immunogenicity of monomeric flagellin and flg22. AFs from plants transiently expressing Epi1 or the empty vector (EV) control were incubated with 10 µg/ml monomeric flagellin or 100 nM flg22 for 40 min and then added to leaf discs of N. benthamiana plants floating on luminol and horse radish peroxidase (HRP). ROS release was measured for 120 min by luminescence (relative light units, RLU) using a plate reader. Lines represent mean, and error shades represent SE of n = 6 replicates. RLU, relative luminescence units.
