The APETALA 2/ethylene-responsive element binding factor (AP2/ERF) superfamily is a large group of transcription factors containing the AP2/ERF-type DNA binding domain. Based on the number of AP2/ERF domains, the AP2/ ERF superfamily proteins can be classified into three groups: AP2, RAV (related to ABI3/VP1), and ERF. The AP2 family protein contains two AP2/ERF domains. The ERF protein possesses one AP2/ ERF domain and finally, the RAV family gene encodes one AP2/ERF domain and a B3 domain. Based on the sequence similarity of AP2/ERF domains, the ERF family is further divided into two subfamilies: ERF and dehydrationresponsive element binding protein (DREB). 12 RAV genes were identified, including JTY(4), LWM(3) and F106(5).