Genome-Wide Identification of Histone Acetyltransferases and Deacetylases in Epiphytic Orchid Plant Dendrobium Catenatum

Background: Dendrobium catenatum is a kind of precious Traditional Chinese Medicine, and possesses unique developmental programs and epiphytic lifestyle. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) are responsible for maintenance of histone acetylation homeostasis, and they are widely involved in developmental regulation and stress responses via remodeling chromatin structure, but their biological functions in orchid plants remain largely unknown.Results: Here we identified 8 HAT genes and 14 HDAC genes from D. catenatum genome. We carried out phylogenetic construction, gene structure and domain architecture analysis of these D. catenatum HAT/HDAC (DcHAT/DcHDAC) proteins using the well-defined homologs from the model plants Arabidopsis thaliana and Oryza sativa as references. DcHAT proteins can be classified into four families: GNAT family (3 members), MYST family (2), CBP family (2), and TAFII250 family (1), and DcHDAC proteins can be grouped into three families: RPD3/HDA1 family (10), SIR2 family (2), and HD2 family (2), in accordance with previously described classification. Cis-acting element analysis indicated that the promoter regions of DcHAT/DcHDAC genes contain diverse stress-responsive elements. Subcellular localization predictions suggested that DcHAT/DcHDAC proteins might be localized in nucleus or/and cytoplasm. Spatiotemporal expression profiling showed that DcHAT/DcHDAC genes generally exhibit either universal or specific expression pattern in different tissues and organs. Finally, stress response assay suggested drought treatment significantly represses the expression of DcHAG1 and DcHDA14, cold exposure evidently influences the expression of DcHAG1 and DcHDT1, and heat shock has a broad impact on the expression of DcHAT/DcHDAC genes.Conclusions: In this study, we reveal the identification and expression profiles of DcHATs and DcHDACs in epiphytic orchid plant D. catenatum, indicating their roles in the regulation of both long-term developmental programs and short-term stress responses. This study provides a foundation for in-depth functional excavation of HATs/HDACs associated with dynamic histone acetylation levels in orchids.