Characterization of Genes for a Putative Hydroxycinnamoyl-coenzyme A Quinate Transferase and <i>p</i>‑Coumarate 3′-Hydroxylase and Chlorogenic Acid Accumulation in Tartary Buckwheat

Tartary buckwheat (Fagopyrum tataricum Gaertn.) contains a high level of flavonoid compounds, which have beneficial and pharmacological effects on health. In this study, we isolated full-length cDNAs encoding hydroxycinnamoyl-coenzyme A quinate hydroxycinnamoyltransferase (HQT) and <i>p</i>-coumarate 3′-hydroxylase (C3H), which are involved in chlorogenic acid (CGA) biosynthesis. We examined the expression levels of HQT and C3H using real-time RT-PCR in different organs and sprouts of two tartary buckwheat cultivars (Hokkai T8 and T10) and analyzed CGA content using high-performance liquid chromatography. Among the organs, the flowers in both cultivars showed the highest levels of CGA. We concluded that the expression pattern of <i>FtHQT</i> and <i>FtC3H</i> did not match the accumulation pattern of CGA in different organs of T8 and T10 cultivars. Gene expression and CGA content varied between the cultivars. We presume that <i>FtHQT</i> and <i>FtC3H</i> levels might be controlled by multiple metabolic pathways in different organs of tartary buckwheat. Probably, <i>FtC3H</i> might have a greater effect on CGA biosynthesis than <i>FtHQT</i>. Our results will be helpful for a greater understanding of CGA biosynthesis in tartary buckwheat.