Comprehensive genome-wide analysis of the DREB gene family in Moso bamboo (Phyllostachys edulis): evidence for the role of PeDREB28 in plant abiotic stress response

Dehydration response element binding (DREB) proteins are vital for plant abiotic stress responses, but the understanding of DREBs in bamboo, an important sustainable non-timber forest product, is limited. Here we conducted a comprehensive genome-wide analysis of the DREB gene family in Moso bamboo, representing the most important running bamboo species in Asia. In total, 44 PeDREBs were identified, and information on their gene structures, protein motifs, phylogenetic relationships, and stress-related cis-regulatory elements (CREs) was provided. Based on the bioinformatical analysis, we further analyzed PeDREBs from the A5 group and found that four of five PeDREB transcripts were induced by salt, drought, and cold stresses, and their proteins could bind to stress-related CREs. Among these, PeDREB28 was selected as a promising candidate for further functional characterization. PeDREB28 is localized in nucleus, has transcriptional activation activity, and could bind to the DRE- and coupling element 1- (CE1) CREs. Overexpression of PeDREB28 in Arabidopsis and bamboo improved plant abiotic stress tolerance. Transcriptomic analysis showed that broad changes due to the overexpression of PeDREB28. Furthermore, 628 genes that may act as the direct PeDREB28 downstream genes were identified by combining DAP-seq and RNA-seq analysis. Moreover, we confirmed that PeDREB28 could bind to the promoter of pyrabactin-resistance-like gene (DlaPYL3), which is a homolog of abscisic acid receptor in Arabidopsis, and activates its expression. In summary, our study provides important insights into the DREB gene family in Moso bamboo, and contributes to their functional verification and genetic engineering applications in the future.