Activation of Cryptic Secondary Metabolite Biosynthesis in Bamboo Suspension Cells by a Histone Deacetylase Inhibitor.

Plants have evolved a diverse array of secondary metabolite biosynthetic pathways. Undifferentiated plant cells, however, tend to biosynthesize secondary metabolites to a lesser extent and sometimes not at all. This phenomenon in cultured cells is associated with the transcriptional suppression of biosynthetic genes due to epigenetic alterations, such as low histone acetylation levels and/or high DNA methylation levels. Here, using cultured cells of bamboo (Bambusa multiplex; Bm) as a model system, we investigated the effect of histone deacetylase (HDAC) inhibitors on the activation of cryptic secondary metabolite biosynthesis. The Bm suspension cells cultured in the presence of an HDAC inhibitor, suberoyl bis-hydroxamic acid (SBHA), exhibited strong biosynthesis of some compounds that are inherently present at very low levels in Bm cells. Two major compounds induced by SBHA were isolated and were identified as 3-O-p-coumaroylquinic acid (1) and 3-O-feruloylquinic acid (2). Their productivities depended on the type of basal culture medium, initial cell density, and culture period, as well as the SBHA concentration. The biosynthesis of these two compounds was also induced by another HDAC inhibitor, trichostatin A. These results demonstrate the usefulness of HDAC inhibitors to activate cryptic secondary metabolite biosynthesis in cultured plant cells.