Functional Characterization of Hedychium coronarium J. Koenig MYB132 Confers the Potential Role in Floral Aroma Synthesis

Abstract

The R2R3-MYB transcription factors (TFs) play several key roles in numerous plant biological processes. <i>Hedychium coronarium</i> is an important ornamental plant well-known for its elegant flower shape and abundant aroma type. The floral aroma of <i>H</i>. <i>coronarium</i> is due to the presence of a large amount of terpenes and benzenoids. However, less is known about the role of R2R3-MYB TFs in the regulatory mechanism of floral aroma production in this breed. Herein, we isolate and functionally characterize the R2R3-MYB TF HcMYB132, which is potentially involved in regulating floral aroma synthesis. Sequence alignment analysis revealed that it includes a nuclear localization signal NLS(s) and a 2R, 3R motif signature in the sequences. A subcellular localization assay revealed that HcMYB132 protein localizes to the nucleus. Real-time qPCR assays showed that <i>HcMYB132</i> is specifically expressed in flowers and its expression pattern correlates with the emission of floral volatile compounds. In <i>HcMYB132</i>-silenced flowers, the levels of floral volatile compounds were significantly reduced, and the expression of key structural volatile synthesis genes was downregulated compared to control. Collectively, these results suggest that <i>HcMYB132</i> might play a significant role in the regulation of terpenoid biosynthesis in <i>H. coronarium</i>.