Genome-Wide Identification of AP2/ERF Transcription Factor Family and Functional Analysis of DcAP2/ERF#96 Associated with Abiotic Stress in Dendrobium catenatum

Abstract

<i>APETALA2/Ethylene Responsive Factor</i> (<i>AP2/ERF</i>) family plays important roles in reproductive development, stress responses and hormone responses in plants. However, <i>AP2/ERF</i> family has not been systematically studied in <i>Dendrobium catenatum</i>. In this study, 120 <i>AP2/ERF</i> family members were identified for the first time in <i>D. catenatum</i>, which were divided into four groups (<i>AP2</i>, <i>RAV</i>, <i>ERF</i> and <i>DREB</i> subfamily) according to phylogenetic analysis. Gene structures and conserved motif analysis showed that each <i>DcAP2/ERF</i> family gene contained at least one AP2 domain, and the distribution of motifs varied among subfamilies. Cis-element analysis indicated that <i>DcAP2/ERF</i> genes contained abundant cis-elements related to hormone signaling and stress response. To further identify potential genes involved in drought stress, 12 genes were selected to detect their expression under drought treatment through qRT-PCR analysis and <i>DcAP2/ERF#96</i>, a nuclear localized ethylene-responsive transcription factor, showed a strong response to PEG treatment. Overexpression of <i>DcAP2/ERF#96</i> in <i>Arabidopsis</i> showed sensitivity to ABA. Molecular, biochemical and genetic assays indicated that <i>DcAP2ERF#96</i> interacts with DREB2A and directly inhibits the expression of P5CS1 in response to the ABA signal. Taken together, our study provided a molecular basis for the intensive study of <i>DcAP2/ERF</i> genes and revealed the biological function of <i>DcAP2ERF#96</i> involved in the ABA signal.