Acts as a transcriptional activator. Binds to the GCC-box pathogenesis-related promoter element. Involved in the regulation of gene expression during the plant development, and/or mediated by stress factors and by components of stress signal transduction pathways. Seems to be a key integrator of ethylene and jasmonate signals in the regulation of ethylene/jasmonate-dependent defenses. Can mediate resistance to necrotizing fungi (Botrytis cinerea and Plectosphaerella cucumerina) and to soil borne fungi (Fusarium oxysporum conglutinans and Fusiarium oxysporum lycopersici), but probably not to necrotizing bacteria (Pseudomonas syringae tomato). Interacts with MED25 and TAF12B. Ubiquitously expressed, mostly in flowers and rosettes after ethylene treatment. Induced by Pseudomonas syringae tomato (both virulent and avirulent avrRpt2 strains), independently of PAD4. Ethylene induction is completely dependent on functional ETHYLENE-INSENSITIVE2 (EIN2), ETHYLENE-INSENSITIVE3 (EIN3), which is itself a transcription factor and CORONATIVE-INSENSITIVE1 (COI1) proteins. Induction by jasmonate, B.cinerea or F.oxysporum as well as the synergistic induction by ethylene and jasmonate requires EIN2 and COI1. Induction by methyl jasmonate (MeJA) is independent of JAR1. Induction by salicylic acid (SA) is dependent on NPR1 but not on PAD4. Seems not to be induced by Alternaria brassicicola. The AP2/ERF domain binds specifically to the 5'-GCCGCC-3' motif. The affinity of this binding is higher if the seventh amino-acid of this domain is basic (By similarity). Belongs to the AP2/ERF transcription factor family. ERF subfamily. Two different genes At3g23240 and At4g17500 were assigned the same gene name ERF1.