Abstract
Caragana. intermedia Kuang et H.C.Fu., a xerophytic deciduous shrub that widely distributed in arid and semi-arid desert areas of North-west China, is highly tolerant to cold, drought, salt-alkali and barren. In this study, the transcriptome C. intermedia under drought treatment was screened for the genes encoding the AP2/ERF family of transcription factors. As a result, 22 sequences with complete open reading frames (ORFs) were obtained. All sequences were divided into 13 groups, including the DREB A1 to A6, ERF B1 to B6, and RAV groups. The results of multiple sequence alignment (MSA) analysis, domain distribution analysis, conservative motif analysis and tertiary structure prediction showed that all the AP2/ERF transcription factors contained the AP2 domain. The AP2 domain contained the YRG and RAYD elements. In addition, quantitative real-time polymerase chain reaction (qRT-PCR) was employed to analyze the expression patterns of the 22 AP2/ERF transcription factors in C. intermedia. Most of the transcription factors exhibited tissue-specific expression. The expression of most transcription factors was induced to varying degrees by cold, heat, salt and mannitol stress. Furthermore, Heterologous expression of CiDREB3 in transgenic Arabidopsis L. Heynh decreased root length and fresh weight, decreased rosette leaf diameter and number of leaf, and improved drought tolerance during seedlings development. Taken together, the results of the present study help to better understand the functions of the AP2/ERF family of transcription factors in plant responses to multiple abiotic stresses and deeply insight the roles of CiDREB3 in Arabidopsis morphology and conferring abiotic stress tolerance.