The 2-week-old transgenic Arabidopsis plant overexpressing 35S:YFP or 35S:YFP-AtWRKY20 and the wild-type Col-0 seedlings were used for ChIP assay. Expressing 35S:YFP line was used as a negative control. Three micrograms of seedlings was fixed in 1% formaldehyde for 10 min in a vacuum. Glycine was added to a final concentration of 0.125 M, and the reaction was terminated by incubation for 5 min in a vacuum. Seedlings were rinsed three times with distilled water and frozen in liquid nitrogen for ChIP experiments. ChIP experiments were performed, as described previously, using anti–green fluorescent protein agarose beads (ChromoTek) for immunoprecipitation (38 (link)). The resulting DNA samples were purified with a PCR Cleanup kit (Axygen). DNA fragments were analyzed by qPCR, with the Arabidopsis ACTIN2 promoter as a reference. Enrichments were referred to the 35S:YFP or 35S:YFP-AtWRKY20 against wild-type seedlings. Primers of ChIP assays are listed in table S1.The experiments were repeated with four independent biological replicates and were repeated twice with similar results.