Search Results
Anthocyanins are protective pigments that accumulate in plant organs such as fruits and leaves, and are nutritionally valuable components of the human diet. The MYB10 transcription factor (TF) plays an important role in regulating anthocyanin biosynthesis in Malus crabapple leaves. However, little is known about how the promoter regulates McMYB10 expression and influences the substantial variation in leaf anthocyanin accumulation and coloration that is observed in different crabapple cultivars. In this study, we analyzed leaf coloration, anthocyanin levels, and the expression levels of McMYB10 in the leaves of 15 crabapple cultivars with three leaf colors at various development stages, and showed that the expression of McMYB10 correlates positively with anthocyanin accumulation. We also examined the relationship between the number of R6 and R1 elements in the McMYB10 promoters of the different cultivars and the pigmentation of the new buds of spring-red cultivars, as well as the methylation level of the McMYB10 promoters at different development stages in three representative crabapple cultivars. The ratio of R6/R1 minisatellites in the promoters correlated with the color and anthocyanin accumulation in new crabapple buds, and we concluded that the differences in promoter structure and methylation level of the McMYB10 promoters coordinately affect the leaf color of crabapple cultivars.
The plant Zantedeschia hybrida is colorful and suitable for cut flowers and potted plants. This study employed a colorimetric method for the determination of spathe color phenotypes in 27 Z. hybrida cultivars and classified them into six major color classes. To characterize the coloration mechanism of the Z. hybrida spathe, this study explored the main colorants and pigment distribution using high-performance liquid chromatography (HPLC) with photodiode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS), ultra-performance liquid chromatography/hybrid triple quadrupole linear ion trap mass spectrometry (UPLC-Q-TRAP-MS), and tissue sections. The results showed that flavonoids were colorants in the spathes of different color groups and that cyanidin (Cy) was the main colorant, whereas carotenoids were not detected in the spathe. Total anthocyanin (TA) content was negatively correlated with lightness (L*) of coloration, such that a spathe with a higher TA and thicker pigmented cell layer showed a deeper color; however, there was no correlation between deep coloration in a spathe and flattened upper epidermal cells. The difference in TA was the main reason for the color variation among Z. hybrida of different color groups, whereas the total flavones and flavonols (TF) played a key role in the coloration of the orange and yellow group.
Anthocyanins are protective pigments that accumulate in plant organs such as fruits and leaves, and are nutritionally valuable components of the human diet. There is thus considerable interest in the factors that regulate synthesis. Malus crabapple leaves are rich sources of these compounds, and in this study we analyzed leaf coloration, anthocyanin levels, and the expression levels of anthocyanin biosynthetic and regulatory genes in three crabapple cultivars (Royalty, Prairifire, and Flame) following various temperature treatments. We found that low temperatures (LTs) promoted anthocyanin accumulation in ‘Royalty’ and ‘Prairifire’, leading to red leaves, but not in ‘Flame’, which accumulated abundant colorless flavonols and retained green colored leaves. Quantitative reverse transcript PCR (RT-PCR) analyses indicated that the expression of several anthocyanin biosynthetic genes was induced by LTs, as were members of the R2R3-MYB, basic helix–loop–helix (bHLH) and WD40 transcription factor families that are thought to act in a complex. We propose that anthocyanin biosynthesis is differentially regulated in the three cultivars by LTs via the expression of members of this anthocyanin regulatory complex.