MYB1 transcription factor regulation through floral scent in Cymbidium cultivar ‘Sael Bit’

Abstract

Cymbidium belongs to Orchidaceae, one of the most abundant angiosperm families. Cymbidium cultivars have a high aesthetic value and commercially valued characteristics such as a pleasant scent and a variety of flower colors. Cymbidium cultivar ‘Sael Bit’, which was developed by National Institute of Horticultural & Herbal Science (NIHHS), is highly fragrant with small green and light yellow flowers. An analysis of ‘Sael Bit’ floral scent emissions by an electronic nose showed that the petal and initial flowering stage emitted a strong scent. In an headspace-solid phase micro extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) ‘Sael Bit’ study, we identified alkenes and benzenoids, such as tridecane, benzene, and Z-2-octenal, as major volatile organic compounds. V-myb myeloblastosis viral oncogene homolog (MYB) transcription factors (TFs) play a positive role in floral scent regulation. However, little is known about the MYB transcriptional regulation of floral scent biosynthesis. Due to the importance of the plant’s biology, we need to study the floral scent MYB TFs in this plant. In the present work, we isolated and cloned the full-length cDNA of Cymbidium cultivar ‘Sael Bit’ MYB1 from fully open flower. CsMYB1 encodes an 840-bp open reading frame and 280 amino acids by functional characterization. In q-RT-PCR expression analysis, CsMYB1 TF showed the highest expression in petals and columns compared to sepals and labella. Moreover, this MYB gene expressed various flower developmental stages and was highly expressed at the fully open flower stage. The phenylpropanoid/benzenoid and ester compounds responsible genes expressed through CsMYB1 TF regulation in q-RT-PCR analysis. According to these results, we suggest that CsMYB1 might be involved in the regulation of phenylpropanoid/benzenoid genes in floral scent profile. In future studies, we will focus on develop regulation models of floral scent in Cymbidium cultivar ‘Sael Bit’.