Transcriptome-wide analysis of AP2/ERF transcription factors involved in regulating Taxol biosynthesis in Taxus x media

The AP2/ERF transcription factor (TF) family plays a key role in response to plant growth and development, biotic and abiotic stresses, but there are few studies on the regulation of Taxol biosynthesis. In this study, approximately 49 genes containing a complete AP2/ERF domain were identified from the Taxus x media (Yew tree) transcriptome database. Amino acid sequences, gene structures, phylogeny, and putative conserved motifs in these 49 TmAP2/ERF (APETALA2/Ethylene-Responsive factor of Taxus x media) proteins were analyzed, and compared with those AP2/ERF of Arabidopsis thaliana. All 49 TmAP2/ERF TFs contained at least one AP2/ERF domain and were divided into four subfamilies (AP2, RAV, DREB, and ERF). Expression analysis showed that nine TmERF genes belonging to DREB and ERF subfamilies can respond to low temperature and hormone treatment, suggesting their involvement in cross-talk between abiotic stress-responsive signaling pathways. Furthermore, the expression pattern of seven TmERF genes was measured using qRT-PCR in response to gibberellin acid (GA(3)). The results indicated that TmERF5, TmERF14, and TmERF36 are highly expressed under gibberellin acid exposure, consistent with the predictions based on transcriptome analysis. These findings will be helpful in understanding AP2/ERF gene-related secondary metabolic and stress response signaling and pathways in Taxus spp. with the aim of improving Taxol yields.