Combined Analysis of the Transcriptome and Metabolome Revealed the Mechanism of Petal Coloration in Bauhinia variegata

Abstract

Bauhinia variegata petals are colorful, rich in anthocyanins, and have ornamental, nutritional, and medicinal value. However, the regulatory mechanism of anthocyanin accumulation in B. variegata remains unclear. In this study, a combined analysis of the metabolome and transcriptome was performed in red and white B. variegata cultivars in the early, middle, and blooming stages. A total of 46 different anthocyanins were identified, of which 27 showed marked differences in accumulation between the two cultivars, and contribute to their different petal colors. Malvidin 3-O-galactoside, peonidin 3-O-galactoside, cyanidin 3-O-glucoside, cyanidin 3-O-galactoside, and malvidin 3-O-glucoside were much more abundant in the second stage of flowering. In the blooming stage, except for the anthocyanins mentioned, delphinidin 3-O-galactoside and petunidin 3-O-galactoside were the most abundant anthocyanins in the red flowers, indicating that malvidin, peonidin, cyanidin, delphinidin, and petunidin were all responsible for the red color of petals in B. variegata. RNA sequencing identified 2,431 differentially expressed genes (DEGs), of which 26 were involved in the anthocyanin synthesis pathway. Correlations between the anthocyanin biosynthesis-related DEGs and anthocyanin contents were explored, and the DEGs involved in anthocyanin accumulation in B. variegata petals were identified. Eighteen of these DEGs encoded key catalytic enzymes, such as anthocyanidin reductase (ANR) and flavonoid-3′5′-hydroxylase (F3′5′H), and 17 of them encoded transcription factors (TFs) belonging to 14 families (including MYB, NAC, SPL, ERF, and CHR28). These results improve our understanding of the roles of anthocyanins, catalytic enzymes, and TFs in B. variegata petal-color expression.

Transcriptomic analysis reveals the mechanism underlying the anthocyanin changes in Fragaria nilgerrensis Schlecht. and its interspecific hybrids

“…In the present study, the expression levels of genes encoding DFR (LOC101293459 and LOC101293749) were higher in BF1 and BF2 than in FN, resulting in the accumulation of anthocyanins in the two interspeci c hybrids (Figure 6). A recent study showed that high DFR expression levels lead to the production of colored anthocyanins in the Mitchell line of Petunia [32]. Similar ndings were reported for Litchi chinensis Sonn [40] and Malus hupehensis [41].…”

“…The results showed that 17 DAMs (primarily pelargonidin and peonidin derivatives) were co-up-regulated (Table 2). Inconsistent with the ndings of previous studies, the abundance of cyanidin derivatives, which produce a magenta fruit skin, was co-down-regulated, indicating that cyanidin derivatives may be lost during the fruit color formation of the FN interspeci c hybrids [32]. In addition, red is closely related to the accumulation of anthocyanins in maturing fruits [33] and the anthocyanin concentration is an important index for examining fruit colors.…”

Transcriptomic analysis reveals the mechanism underlying the anthocyanin changes in Fragaria nilgerrensis Schlecht. and its interspecific hybrids

“…The results showed that 17 DAMs (primarily pelargonidin and peonidin derivatives) were co-up-regulated (Table 2 ). Inconsistent with the findings of previous studies, the abundance of cyanidin derivatives, which produce a magenta fruit skin, was co-down-regulated, indicating that cyanidin derivatives may be lost during the fruit color formation of the FN interspecific hybrids [ 32 ].…”

“…6 ). A recent study showed that high DFR expression levels lead to the production of colored anthocyanins in the Mitchell line of Petunia [ 32 ]. Similar findings were reported for Litchi chinensis Sonn [ 40 ] and Malus hupehensis [ 41 ].…”

Involvement of Transcription Factors and Regulatory Proteins in the Regulation of Carotenoid Accumulation in Plants and Algae

“…Until now, only limited regulators have been experimentally verified to be involved in the regulation of carotenoid metabolism in algae. For further study, by referring to relevant studies in plants through homology of regulatory factors, muti-omics integration analysis of metabolomics and transcriptomics, and molecular biology techniques, ,,, much more regulators and regulation networks can be discovered in algae. Among them, comparative transcriptome sequencing can be an important means to explore potential regulatory factors according to the correlation of gene expression and carotenoid contents …”