Molecular Characterization of MYB Transcription Factor Genes from Panax ginseng

Transcription factors (TFs) are essential for gene regulation in all living organisms, including plants, where among numerous other functions, they control temporal and spatial gene expression in response to environmental stimuli. The v-myb avian myeloblastosis viral oncogene homolog (MYB) family is the largest TF family in plants, with its members involved in developmental processes as well as secondary metabolism. Little is known about MYB genes in Panax ginseng Meyer, despite ginseng's importance as a widely-used medicinal plant. In this study, we isolated nine MYB genes from P. ginseng (PgMYBs). Phylogenetic comparison of these genes with the MYB genes of other plant species revealed that the PgMYBs clustered into different families based on their putative functions including terpene regulation; five PgMYBs clustered in the R2R3 family, and four PgMYBs clustered in the MYB-related protein group. Further expression analysis of five PgMYBs showed consistently high expression in flower and leaf tissue, suggesting that these PgMYB genes may be involved in development of the above-mentioned tissues. Four PgMYBs were downregulated in response to methyl jasmonate (MJ) and salicylic acid (SA), whereas PgMYB3 was up-regulated, suggesting a role for all these genes in stress response. This is the first comprehensive study of the MYB gene family in P. ginseng, and the information provided here will facilitate further exploration of the functions of these TFs.