Flower Color Pigmentation Research Articles

Fine Mapping and Candidate Gene Identification of a White Flower Gene BrWF3 in Chinese Cabbage (Brassica rapa L. ssp. pekinensis).

Flower color is an important trait in plants. However, genes responsible for the white flower trait in Chinese cabbage are rarely reported. In this study, we constructed an F2 population derived from the Y640-288 (white flower) and Y641-87 (yellow flower) lines for the fine mapping of the white flower gene BrWF3 in Chinese cabbage. Genetic analysis indicated that BrWF3 was controlled by a single recessive gene. Using BSA-seq and KASP assays, BrWF3 was fine-mapped to an interval of 105.6 kb. Functional annotation, expression profiling, and sequence variation analyses confirmed that the AtPES2 homolog, Bra032957, was the most likely candidate gene for BrWF3. Carotenoid profiles and transmission electron microscopy analysis suggested that BrWF3 might participate in the production of xanthophyll esters (particularly violaxanthin esters), which in turn disrupt chromoplast development and the formation of plastoglobules (PGs). A SNP deletion in the third exon of BrWF3 caused the loss of protein function, and interfered with the normal assembly of PGs, which was associated with reduced expression levels of genes involved in carotenoid metabolism. Furthermore, we developed and validated the functional marker TXBH83 for BrWF3. Our results provide insight into the molecular mechanism underlying flower color pigmentation and reveal valuable information for marker-assisted selection (MAS) breeding in Chinese cabbage.

Identification of the regulatory networks and hub genes controlling alfalfa floral pigmentation variation using RNA-sequencing analysis

BackgroundTo understand the gene expression networks controlling flower color formation in alfalfa, flowers anthocyanins were identified using two materials with contrasting flower colors, namely Defu and Zhongtian No. 3, and transcriptome analyses of PacBio full-length sequencing combined with RNA sequencing were performed, across four flower developmental stages.ResultsMalvidin and petunidin glycoside derivatives were the major anthocyanins in the flowers of Defu, which were lacking in the flowers of Zhongtian No. 3. The two transcriptomic datasets provided a comprehensive and systems-level view on the dynamic gene expression networks underpinning alfalfa flower color formation. By weighted gene coexpression network analyses, we identified candidate genes and hub genes from the modules closely related to floral developmental stages. PAL, 4CL, CHS, CHR, F3’H, DFR, and UFGT were enriched in the important modules. Additionally, PAL6, PAL9, 4CL18, CHS2, 4 and 8 were identified as hub genes. Thus, a hypothesis explaining the lack of purple color in the flower of Zhongtian No. 3 was proposed.ConclusionsThese analyses identified a large number of potential key regulators controlling flower color pigmentation, thereby providing new insights into the molecular networks underlying alfalfa flower development.

Isolation and functional analysis of a homolog of flavonoid 3′,5′‐hydroxylase gene from Pericallis × hybrida

As the key enzyme in the biosynthesis of blue flower color pigments, flavonoid 3',5'-hydroxylase (F3'5'H) can catalyze the conversion of its major substrates, 2-S naringenin and dihydrokaempferol, into 3',4',5'-hydroxylated pentahydroxyflavanone and dihydromyricetin, respectively. Unlike other F3'5'Hs belonging to the CYP75A subfamily, Asteraceae-specific F3'5'Hs belong to the CYP75B subfamily. Furthermore, cineraria F3'5'H expressed in yeast exhibited not only F3'H (flavonoid 3'-hydroxylase) activity but also F3'5'H activity in vitro. In this study, Southern blotting showed that there was only one copy of a homolog of the F3'5'H gene PCFH in the Pericallis × hybrida genome. This gene could be detected by Northern blot in the primary developmental stages of ligulate florets of the purple- and blue-flowered cultivars, and its transcripts also accumulated in the leaves. Heterologous expression of PCFH could produce new delphinidin derivatives in the corollas of transgenic tobacco plants, increased the content of cyanidin derivatives and lead to the blue- and red-shifting of flower color in T₀ generation plants. These results indicate that cineraria F3'5'H exhibited both F3'5'H- and F3'H-activity in vivo. The types and contents of anthocyanins and flower color phenotypes of the T₁ generation were similar to those of T₀ generation plants. PCFH exhibited stable inheritance and normal functions between generations. This study supplies new evidence to understand Asteraceae-specific F3'5'Hs and provides important references for the further study of molecular breeding of blue-flowered chrysanthemums using the PCFH gene.

ChemInform Abstract: Recent Progress in the Chemistry of Polyacylated Anthocyanins as Flower Color Pigments

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Recent Progress in the Chemistry of Polyacylated Anthocyanins as Flower Color Pigments

It is recognized that the bluing effect and stabilization of flower colors will remarkably depend on the number of aromatic acids presented in the polyacylated anthocyanins. Although polyacyl functions would be consideredto contribute strongly in the bluing of the flower color at the early stage of the investigation of polyacylated anthocyanin chemistry, the stabilization of flower color is considered to be another important objective by the presence of these aromatic acids at the present time. Since aromatic acids in the polyacylated anthocyanins are obviously linked with the sugar residues through the ester bonds, the polyacylated anthocyanins are classified into seven types by the substitution pattern of acyl functions, and the effect of the stacking structures of polyacyl anthocyanins on the stabilization of the flower color depending on the substitution pattern of acyl groups will be discussed. The physicochemical properties (NMR, UV-VIS spectra) in relation to the stability of the anthocyanins will also be discussed.

Identity of normal and mutant flower-color pigments in four different Tradescantia clones confirmed by means of microspectrophotometry.

As a step to investigate the genetic identity of normal blue and mutant pink flower-color pigments in four different Tradescantia clones (BNL 02, KU 27, KU 9 and KU 20), which are heterozygous for flower color (blue/pink), the light absorption spectra of the normal blue and mutant pink cells in their stamen hairs were measured microspectrophotometrically. It was found that the blue cells of all the four clones showed the maximum absorption peak at 574 nm, the second peak at 618 nm, and a shoulder at around 544 nm. It was also found that the pink cells of all these clones had two absorption peaks at 546 and 586 nm and a shoulder at around 512 nm. These findings prove that all the four clones examined produce the identical blue-color pigment normally, and also the identical pink-color pigment when the dominant gene for the blue color underwent mutation. One leaky mutant (intermediately colored) hair cell of clone BNL 02 was shown to be producing both the blue- and pink-color pigments.

Identity of normal and mutant flower-color pigments in four different Tradescantia clones confirmed by means of microspectrophotometry

Identity of normal and mutant flower-color pigments in four different Tradescantia clones confirmed by means of microspectrophotometry