An Integrated Analysis of Metabolomics and Transcriptomics Reveals Significant Differences in Floral Scents and Related Gene Expression between Two Varieties of Dendrobium loddigesii

Abstract

Flower fragrance is one of the traits that holds important economical values in flowering plants. Extensive attention has converged on fragrance preservation in flower cultivation and breeding. Dendrobium loddigesii is an important species for cultivating aromatic Dendrobium orchid varieties for the long term due to its fragrance. Few studies focus on exploring related genes responsible for the aroma components in D. loddigesii. We analyzed flowers from two aromatic D. loddigesii varieties using high-throughput RNA sequencing and gas chromatography-mass spectrometry (GC-MS). The metabolomics results showed that the main volatile compounds responsible for the aroma formation of D. loddigesii were terpenes, especially monoterpenes. The de novo transcriptome assembly comprised 175,089 unigenes, and 24,570 unigenes of the genes were identified as differential expressed genes (DEGs) between the two varieties. Among these DEGs, 525 genes were mapped into seven pathways that related to the floral scent synthesis. Seventeen key genes were significantly correlated with volatile aroma metabolites, including geraniol, α-pinene, eugenol, and (Z)-3-hexenal. These results provide references for understanding the aroma biosynthesis and perfume formulations of D. loddigesii.

Identification of the carotenoid cleavage dioxygenase genes and functional analysis reveal DoCCD1 is potentially involved in beta-ionone formation in Dendrobium officinale

“…In our present study, among the volatile components in the stem and leaf, the relatively abundant beta-ionone was found ( Figure 2 ), which was similar to the previous report ( Ma et al, 2018 ). Beta-ionone was also detected in the fresh flowers of D. loddigesii ( Wang S. et al, 2022 ). No beta-ionone was detected in some reports ( Chen et al, 2016 ; Hu et al, 2020 ), which might be due to the different methods applied.…”

Integrated metabolome and transcriptome analysis provides insights on the floral scent formation in Hydrangea arborescens

“…The majority of this volatiles are terpenoids (monoterpenes and sesquiterpenes), followed by benzenoids/phenylpropanoids (Table S1). Similarly, terpenoids and benzenoids/phenylpropanoids were the main aroma compounds in several flowering species, including Paeonia suffruticosa (Zhang et al, 2021), Freesia x hybrida (Gao et al, 2018), Dendrobium loddigesii (Wang, Du, et al, 2022), Lycoris longituba (Yue et al, 2019), H. coronarium (Zhou, Abbas, et al, 2022; Zhou et al, 2021), L. chinensis (Abbas, Guo, et al, 2022), and Cymbidium faberi (Wang et al, 2021).…”

“…The majority of this volatiles are terpenoids (monoterpenes and sesquiterpenes), followed by benzenoids/ phenylpropanoids (Table S1). Similarly, terpenoids and benzenoids/ phenylpropanoids were the main aroma compounds in several flowering species, including Paeonia suffruticosa (Zhang et al, 2021), Freesia x hybrida (Gao et al, 2018), Dendrobium loddigesii (Wang, Du, et al, 2022), F I G U R E 6 Terpenoids biosynthetic pathway and expression analysis of related genes in "Annabelle." The terpenoid pathway occurs mainly in the cytosol and plastids.…”

The LibHLH22 and LibHLH63 from Lilium ‘Siberia’ Can Positively Regulate Volatile Terpenoid Biosynthesis

“…[1,2]. To make better use of floral fragrance in order to meet people's daily life needs, the compounds, release rules, and molecular regulatory mechanisms of various fragrant flowers have been studied deeply, such as rose, peony, orchid, wintersweet, freesia, dendrobium, osmanthus, oncidium, plum blossom, and Hedychium coronarium [3][4][5][6][7][8][9][10][11][12][13][14]. Lilies are also known as famous fragrant flowers, and therefore, the composition and biosynthesis of their floral fragrance have been extensively studied.…”