Integrated transcriptomics and metabolomics analysis provide insight into anthocyanin biosynthesis for sepal color formation in Heptacodium miconioides

Abstract

Heptacodium miconioides Rehd., commonly known as “seven-son flower,” is an ornamental species with a beautiful flower pattern and persistent sepals. Its sepals are of horticultural value, turning bright red and elongating in the autumn; however, the molecular mechanisms that cause sepal color change remain unclear. We analyzed the dynamic changes in anthocyanin composition in the sepal of H. miconioides at four developmental stages (S1-S4). A total of 41 anthocyanins were detected and classified into 7 major anthocyanin aglycones. High levels of the pigments cyanidin-3,5-O-diglucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, and pelargonidin-3-O-glucoside were responsible for sepal reddening. Transcriptome analysis revealed 15 differentially expressed genes involved in anthocyanin biosynthesis that were detected between 2 developmental stages. Of these, the high expression of HmANS was considered critical structural gene related to anthocyanin biosynthesis pathway in the sepal through co-expression analysis with anthocyanin content. In addition, a transcription factor (TF)-metabolite correlation analysis revealed that three HmMYB, two HmbHLH, two HmWRKY, and two HmNAC TFs exhibited a strong positive role in the regulation of the anthocyanin structural genes (Pearson’s correlation coefficient > 0.90). Luciferase activity assay showed that HmMYB114, HmbHLH130, HmWRKY6, and HmNAC1 could activate the promoters of HmCHS4 and HmDFR1 genes in vitro. These findings increase our understanding of anthocyanin metabolism in the sepal of H. miconioides and provide a guide for studies involving sepal color conversion and regulation.

Targeted Metabolome and Transcriptome Analyses Reveal the Molecular Mechanism of Color Variation between Sepals and Petals in Fuchsia hybrida

“…Usually, the sepals exhibit green colors because of the chlorophyll accumulation, while petals show a wider range of colors caused by the synthesis of abundant secondary metabolites, including flavonoids, carotenoids and betaines. However, the sepals of a few plants possess the ability to accumulate anthocyanins instead of chlorophylls, such as delphinidins in H. macrophylla [31,32], and cyanidins and pelargonidins in Heptacodium miconioides [33]. In this study, the anthocyanins in the red sepals of F. hybrida were mainly cyanidin and peonidin derivatives, different from the malvidin derivatives accumulating in its purple petals (Figure 2, Table S3).…”

Emerging Research Advancements to Overcome the Peach Spring Frost

“…The identified metabolites, such as flavonoids, soluble sugars, and lignin, including galactose, manninotriose, glucose, luteolin, and coniferin, were found to play important roles in 1-year-old peach branches in response to cold. The findings concluded that the galactose metabolism, phenylpropanoid biosynthesis, and flavonoids biosynthesis pathways were associated with the low temperature tolerance of peaches (Li et al, 2023).…”

Molecular mechanism of flower color formation in Rhododendron simsii Planchon revealed by integration of microRNAome and RNAomics

“…In particular, the most abundant sRNAs were 24 nt, followed by 21 nt and 22 nt in all three varieties. The rRNAs (853,418-1,354,362), snoRNA (25,637), snRNA (1,494-3,088), sRNA (17,859), and tRNA (3,346) were annotated through searching against GenBank, tRNAdb, Rfam, Repbase, and Silva databases (Table 5).…”

“…Flower color, important objective in ornamental plant breeding, are controled by integrated effects of pigment composition, pH, cell shape, and copigmentation (Sinopoli et al 2019; Wang et al 2023;Li et al 2023). Several hundred genes associated with ower color formation, containing transcription factors, transcriptional co-regulators, proteins involved in epigenetic control of gene expression, and microRNAs, have been well identi ed in model plant (Selva et al 2021; Guan et al 2021;Ren et al 2021;Takeda et al 2023).…”