Comprehensive analysis of AP2/ERF gene members in Acer truncatum B. and the positive regulator role of AtruDREB28 in drought tolerance

Abstract

APETALA2/Ethylene Responsive Factor (AP2/ERF) play pivotal roles in resisting diverse stresses and in regulating growth and development in plant, but the information and function of the AP2/ERF genes are not well elucidated in Acer truncatum B. As an important woody tree producing oil with high economic values, A. truncatum has strong tolerance to drought. AP2/ERF may implicate in drought stress tolerance and growth of A. truncatum. In the current research, the AtruAP2/ERF family members were identified and comprehensive bioinformatics analysis were performed, including phylogenetic relationship, gene/protein structure, expression pattern, cis-acting element, protein interaction network, and functional characterization of AtruDREB28. Total of 117 AtruAP2/ERF members were identified in A. truncatum genome and were divided into five subfamilies, AP2 (17 genes), ERF (61 genes), DREB (35 genes), RAV (3 genes), and Soloist (one gene). The members from same clade exhibited relatively similar gene structure and motif compositions. Fifty-seven duplication events were identified in AtruAP2/ERF family, containing eight pairs generated from fragmental duplication, and 49 pairs generated from tandem duplication. Subsequently, a variety of cis-acting elements associated with development, hormone, and stress were identified in the promoter regions of AtruAP2/ERF, such as ARE, MBS, ABRE, TCA, etc. A potential interaction network of AtruAP2/ERFs was conducted to predict the interaction relationships. In addition, tissue expression analysis showed that majority of AtruAP2/ERFs exhibited tissue specific modes. The expression profiles of the majority of AtruAP2/ERFs were induced in response to drought stress, suggesting that AtruAP2/ERFs were involved in the modulation of drought stress response. Furthermore, overexpression of AtruDREB28 increased the tolerance to drought stress by enhancing the reactive oxygen species-scavenging capability. Together, these results give insights into the characteristics and functional analysis of AtruAP2/ERF genes in A. truncatum.