Fig. 1.

Cutin polymer, but not pure cutin constituents, activates a ROS burst. Luminescence-based detection of apoplastic ROS in Arabidopsis Col-0 leaf discs upon treatment with 2 mg ml^–1 cutin in MilliQ water for 30 min (A) and 45 min (B); (C) 1 mM of commercially available pure monomers [16-hydroxypalmitic acid (16-HPA), octanedioic acid (OCTDA), and ferulic acid (FERA)] and oligomers [glyceryl stearate (GS) and glyceryl tristearate (GTS)], in 10% ethanol in MilliQ water for 45 min; (D) 1 mg ml^–1 of cutin hydrolysate obtained after alkaline hydrolysis of cutin; (E) 2 mg ml^–1 of COM obtained through the methanolysis of cutin in 0.5% DMSO in MilliQ water; and (F) co-treatment with 2 mg ml^–1 COM and 100 nM Flg22 in 0.5% DMSO in MilliQ water. In all the assays, mock consists of the solvent. The positive controls were Flg22 (100 nM) or Pep1 (100 nM).