Transcriptome-based analysis of carotenoid accumulation-related gene expression in petals of Chinese cabbage (Brassica rapa L.)

Abstract

To identify genes associated with carotenoid accumulation in petals of Chinese cabbage, the composition and content of carotenoids were analyzed, and comparative transcriptome sequencing was performed between the yellow flower line, 92S105, and the orange flower line, 94C9. High-performance liquid chromatography (HPLC) revealed that petals of 92S105 were high in violaxanthin as well as lutein, whereas petals of 94C9 showed considerable levels of lutein and β-carotene. Transcriptome analysis showed that 3534 and 3833 genes were up-and down-regulated in 94C9, respectively. Among these differentially expressed genes (DEGs), many related to carotenoid accumulation were identified, including 12 carotenoid biosynthesis pathway genes, 4 transcription factor genes, and 1028 specifically expressed genes. β-carotene hydroxylase 1 (BrBCH1), BrBCH2, zeaxanthin epoxidase (BrZEP), and MYB transcription factor gene (BrGAMYB) were down-regulated in petals of 94C9 when compared with petals of 92S105, which caused β-carotene accumulation and may lead to orange petal color in 94C9. Expression levels of 20 DEGs were verified by qPCR and the results were highly consistent with those of transcriptome sequencing. Moreover, Gene Ontology (GO) enrichment analysis revealed that membrane, binding, and metabolic processes were the most significantly enriched GO terms in cellular component, molecular function, and biological process ontologies, respectively. In conclusion, our study analyzed the differences in composition and content of carotenoids between 92S105 and 94C9 and identified potential candidate genes related to carotenoid accumulation in petals, thereby creating a solid foundation for future studies on the mechanism regulating carotenoid accumulation in petals of Chinese cabbage.

COMT, CRTZ, and F3’H regulate glycyrrhizic acid biosynthesis in Glycyrrhiza uralensis hairy roots

“…We nd that the color of the hairy roots of the CRTZ − lines looks reddish, indicating a high content of β-carotene, whereas the color of the hairy roots of the CRTZ + lines appears pale, suggesting a low content of β-carotene. It has also been observed in Brassica rapa and Oncidium hybridum that down-regulation of CRTZ causes the accumulation of β-carotene and makes the ower color to turn from yellow to orange (Chiou et al 2010;Zhang et al 2019). It is thus likely that knocking out CRTZ increases the GA contents through promoting the accumulation of β-carotene in G. uralensis hairy roots.…”

Selection and Validation of qRT-PCR Internal Reference Genes to Study Flower Color Formation in Camellia impressinervis

“…The unique floral pigmentation is primarily attributed to the petal’s structural attributes and the composition and concentration of cellular pigments, notably flavonoids and carotenoids [ 4 , 5 , 6 , 7 ]. These pigments are synthesized through complex enzymatic pathways: flavonoid biosynthesis necessitates enzymes including phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), and dihydroflavonol 4-reductase (DFR) [ 8 , 9 , 10 , 11 ]; carotenoid biosynthesis involves enzymes such as phytoene desaturase (PDS), carotenoid isomerase (CRTISO), lycopene ε-cyclase (LCYE), lycopene β-cyclase (LCYB), β-carotene hydroxylase (BCH), and zeaxanthin epoxidase (ZEP) [ 12 , 13 , 14 , 15 , 16 ]. Current literature on the molecular mechanisms influencing golden camellia flower coloration is scant.…”