Integrative analysis of transcriptome and metabolome reveals flavonoid biosynthesis regulation in Rhododendron pulchrum petals

Abstract

Background Color is the major ornamental feature of the Rhododendron genus, and it is related to the contents of flavonoid in petals. However, the regulatory mechanism of flavonoid biosynthesis in Rhododendron pulchrum remains unknown. The transcriptome and metabolome analysis of Rhododendron pulchrum with white, pink and purple color in this study aimed to reveal the mechanism of flavonoid biosynthesis and to provide insight for improving the petal color. Results Flavonoids and flavonols are the major components of flavonoid metabolites in R.pulchrum, such as laricitrin, apigenin, tricin, luteolin, isoorientin, isoscutellarein, diosmetin and their glycosides derivatives. With transcriptome and metabolome analysis, we found CHS, FLS, F3’H, F3′5’H, DFR, ANS, GT, FNS, IFR and FAOMT genes showed significantly differential expression in cultivar ‘Zihe'. FNS and IFR were discovered to be associated with coloration in R.pulchrum for the first time. The FNS gene existed in the form of FNSI. The IFR gene and its related metabolites of medicarpin derivatives were highly expressed in purple petal. In cultivar ‘Fenhe', up-regulation of F3’H and F3′5’H and down-regulation of 4CL, DFR, ANS, and GT were associated with pink coloration. With the transcription factor analysis, a subfamily of DREBs was found to be specifically enriched in pink petals. This suggested that the DREB family play an important role in pink coloration. In cultivars ‘Baihe', flavonoid biosynthesis was inhibited by low expression of CHS, while pigment accumulation was inhibited by low expression of F3′5'H, DFR, and GT, which led to a white coloration. Conclusions By analyzing the transcriptome and metabolome of R.pulchrum, principal differential expression genes and metabolites of flavonoid biosynthesis pathway were identified. Many novel metabolites, genes, and transcription factors associated with coloration have been discovered. To reveal the mechanism of the coloration of different petals, a model of the flavonoid biosynthesis pathway of R.pulchrum was constructed. These results provide in depth information regarding the coloration of the petals and the flavonoid metabolism of R.pulcherum. The study of transcriptome and metabolome profiling gains insight for further genetic improvement in Rhododendron.

Comparative transcriptomic and metabolomic analyses reveal differences in flavonoid biosynthesis between PCNA and PCA persimmon fruit

“…F3'5'H (evm.TU.contig31.16) catalyzes the synthesis of dihydromyricetin, a substrate of leucodelphinidin. These results are consistent with those of similar studies of Rhododendron pulchrums (Xia et al, 2022).…”

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Integrated metabolome, full‐length sequencing, and transcriptome analyses unveil the molecular mechanisms of color formation of the canary yellow and red bracts of Bougainvillea × buttiana ‘Chitra’

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Intracellular metabolomics and microRNAomics unveil new insight into the regulatory network for potential biocontrol mechanism of stress‐tolerant Tricho‐fusants interacting with phytopathogen Sclerotium rolfsii Sacc

“…The potent Trichoderma was employed mycoparasitism as a biocontrol action to restrain fungal pathogen (Hirpara & Gajera, 2020), and providing an environmentally sound alternative to chemical fungicides in the management of different pathogens. “Omics” technologies, including metabolomics and transcriptomics might be provided information on the global profile, and are therefore regarded as powerful tools to investigate molecular mechanisms of various traits for crop improvement and protection (Guo et al, 2022; Xia et al, 2022). The miRNAs interfering with the regulation of genes and pathways are not clearly explored to understand molecular mechanisms in agriculturally beneficial fungi.…”

“…"Omics" technologies, including metabolomics and transcriptomics might be provided information on the global profile, and are therefore regarded as powerful tools to investigate molecular mechanisms of various traits for crop improvement and protection (Guo et al, 2022;Xia et al, 2022). The miRNAs interfering with the regulation of genes and pathways are not clearly explored to understand molecular mechanisms in agriculturally beneficial fungi.…”