Genome-Wide Identification and Expression Pattern Analysis of BAHD Acyltransferase Family in Taxus mairei

BAHD acyltransferases are involved in catalyzing and regulating the secondary metabolism in plants. Despite this, the members of BAHD family and their functions have not been reported in the Taxus species. In this study, a total of 123 TwBAHD acyltransferases from Taxus wallichiana var. mairei genome were identified and divided into six clades based on phylogenetic analysis, of which Clade VI contained a Taxus-specific branch of 52 members potentially involved in taxol biosynthesis. Most TwBAHDs from the same clade shared similar conserved motifs and gene structures. Besides the typical conserved motifs within the BAHD family, the YPLAGR motif was also conserved in multiple clades of T. mairei. Moreover, only one pair of tandem duplicate genes was found on chromosome 1, with a Ka/Ks ratio < 1, indicating that the function of duplicate genes did not differentiate significantly. RNA-seq analysis revealed different expression patterns of TwBAHDs in MeJA induction and tissue-specific expression experiments. Several TwBAHD genes in the Taxus-specific branch were highly expressed in different tissues of T. mairei, suggesting an important role in the taxol pathway. This study provides comprehensive information for the TwBAHD gene family and sets up a basis for its potential functions.