scholarly journals A Roadmap to Modulated Anthocyanin Compositions in Carrots

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 472 ◽  
Author(s):  
Inger Bæksted Holme ◽  
Giuseppe Dionisio ◽  
Henrik Brinch-Pedersen

Anthocyanins extracted from black carrots have received increased interest as natural colorants in recent years. The reason is mainly their high content of acylated anthocyanins that stabilizes the color and thereby increases the shelf-life of products colored with black carrot anthocyanins. Still, the main type of anthocyanins synthesized in all black carrot cultivars is cyanidin limiting their use as colorants due to the narrow color variation. Additionally, in order to be competitive against synthetic colors, a higher percentage of acylated anthocyanins and an increased anthocyanin content in black carrots are needed. However, along with the increased interest in black carrots there has also been an interest in identifying the structural and regulatory genes associated with anthocyanin biosynthesis in black carrots. Thus, huge progress in the identification of genes involved in anthocyanin biosynthesis has recently been achieved. Given this information it is now possible to attempt to modulate anthocyanin compositions in black carrots through genetic modifications. In this review we look into genetic modification opportunities for generating taproots of black carrots with extended color palettes, with a higher percentage of acylated anthocyanins or a higher total content of anthocyanins.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lin-Jiang Ye ◽  
Michael Mӧller ◽  
Ya-Huang Luo ◽  
Jia-Yun Zou ◽  
Wei Zheng ◽  
...  

Abstract Background The Rhododendron sanguineum complex is endemic to alpine mountains of northwest Yunnan and southeast Tibet of China. Varieties in this complex exhibit distinct flower colors even at the bud stage. However, the underlying molecular regulations for the flower color variation have not been well characterized. Here, we investigated this via measuring flower reflectance profiles and comparative transcriptome analyses on three coexisting varieties of the R. sanguineum complex, with yellow flush pink, bright crimson, and deep blackish crimson flowers respectively. We compared the expression levels of differentially-expressed-genes (DEGs) of the anthocyanin / flavonoid biosynthesis pathway using RNA-seq and qRT-PCR data. We performed clustering analysis based on transcriptome-derived Single Nucleotide Polymorphisms (SNPs) data, and finally analyzed the promoter architecture of DEGs. Results Reflectance spectra of the three color morphs varied distinctively in the range between 400 and 700 nm, with distinct differences in saturation, brightness, hue, and saturation/hue ratio, an indirect measurement of anthocyanin content. We identified 15,164 orthogroups that were shared among the three varieties. The SNP clustering analysis indicated that the varieties were not monophyletic. A total of 40 paralogous genes encoding 12 enzymes contributed to the flower color polymorphism. These anthocyanin biosynthesis-related genes were associated with synthesis, modification and transportation properties (RsCHS, RsCHI, RsF3H, RsF3′H, RsFLS, RsANS, RsAT, RsOMT, RsGST), as well as genes involved in catabolism and degradation (RsBGLU, RsPER, RsCAD). Variations in sequence and cis-acting elements of these genes might correlate with the anthocyanin accumulation, thus may contribute to the divergence of flower color in the R. sanguineum complex. Conclusions Our results suggested that the varieties are very closely related and flower color variations in the R. sanguineum complex correlate tightly with the differential expression levels of genes involved in the anabolic and catabolic synthesis network of anthocyanin. Our study provides a scenario involving intricate relationships between genetic mechanisms for floral coloration accompanied by gene flow among the varieties that may represent an early case of pollinator-mediated incipient sympatric speciation.


Genes ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 906 ◽  
Author(s):  
Massimo Iorizzo ◽  
Julien Curaba ◽  
Marti Pottorff ◽  
Mario G. Ferruzzi ◽  
Philipp Simon ◽  
...  

Purple or black carrots (Daucus carota ssp. sativus var. atrorubens Alef) are characterized by their dark purple- to black-colored roots, owing their appearance to high anthocyanin concentrations. In recent years, there has been increasing interest in the use of black carrot anthocyanins as natural food dyes. Black carrot roots contain large quantities of mono-acylated anthocyanins, which impart a measure of heat-, light- and pH-stability, enhancing the color-stability of food products over their shelf-life. The genetic pathway controlling anthocyanin biosynthesis appears well conserved among land plants; however, different variants of anthocyanin-related genes between cultivars results in tissue-specific accumulations of purple pigments. Thus, broad genetic variations of anthocyanin profile, and tissue-specific distributions in carrot tissues and organs, can be observed, and the ratio of acylated to non-acylated anthocyanins varies significantly in the purple carrot germplasm. Additionally, anthocyanins synthesis can also be influenced by a wide range of external factors, such as abiotic stressors and/or chemical elicitors, directly affecting the anthocyanin yield and stability potential in food and beverage applications. In this study, we critically review and discuss the current knowledge on anthocyanin diversity, genetics and the molecular mechanisms controlling anthocyanin accumulation in carrots. We also provide a view of the current knowledge gaps and advancement needs as regards developing and applying innovative molecular tools to improve the yield, product performance and stability of carrot anthocyanin for use as a natural food colorant.


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 564
Author(s):  
Federica Blando ◽  
Stefano Marchello ◽  
Gabriele Maiorano ◽  
Miriana Durante ◽  
Angelo Signore ◽  
...  

The carrot is one of the most cultivated vegetables in the world. Black or purple carrots contain acylated anthocyanins which are of special interest to the food industry for their stability and nutraceutical characteristics. Anthocyanin-rich fruits and vegetables have gained popularity in the last ten years, due to the health benefits they provide. In this paper, the characterizations of the bioactive compounds and antioxidant capacities of different anthocyanin-containing carrots (a black carrot—BC, and a local purple carrot, the “Polignano” carrot—PC), compared to the commercial orange carrot (OC) (lacking of anthocyanins), are reported. The anthocyanin profiles of the polyphenolic extracts of BC and PC were similar, but differences were observed at quantitative levels. The total anthocyanin content in BC was more than twice that in PC (13.84 ± 0.61 vs. 5.64 ± 0.48 mg K Eq. g−1 DW). Phenolic acids (mostly chlorogenic acid) were also present at high level in anthocyanin-rich carrots compared to OC. High polyphenol content accounted also for a high reducing capacity (evaluated by Folin–Ciocalteu reagent, FCR), and antioxidant capacity (evaluated by TEAC and ORAC assays) which were the highest for BC (FCR value: 16.6 ± 1.1 mg GAE. g−1 DW; TEAC: 76.6 ± 10.6 µmol TE. g−1 DW; ORAC: 159.9 ± 3.3 µmol TE. g−1 DW). All carrot genotypes (mostly OC) were rich in carotenoids (BC 0.14 ± 0.024; PC 0.33 ± 0.038; OC 1.29 ± 0.09 mg. g−1 DW), with predominance of α and β-carotene, in OC, and lutein in BC. PC showed the highest malic acid and sugar (glucose plus fructose) content. In conclusion, while BC is remarkable for nutraceutical features, the local genotype (“Polignano” carrot) is worth considering in genetic biodiversity conservation programme.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Guanghui An ◽  
Jiongjiong Chen

Abstract Background Mustard (Brassica juncea) is an important economic vegetable, and some cultivars have purple leaves and accumulate more anthocyanins than the green. The genetic and evolution of purple trait in mustard has not been well studied. Result In this study, free-hand sections and metabolomics showed that the purple leaves of mustard accumulated more anthocyanins than green ones. The gene controlling purple leaves in mustard, Mustard Purple Leaves (MPL), was genetically mapped and a MYB113-like homolog was identified as the candidate gene. We identified three alleles of the MYB113-like gene, BjMYB113a from a purple cultivar, BjMYB113b and BjMYB113c from green cultivars. A total of 45 single nucleotide polymorphisms (SNPs) and 8 InDels were found between the promoter sequences of the purple allele BjMYB113a and the green allele BjMYB113b. On the other hand, the only sequence variation between the purple allele BjMYB113a and the green allele BjMYB113c is an insertion of 1,033-bp fragment in the 3’region of BjMYB113c. Transgenic assay and promoter activity studies showed that the polymorphism in the promoter region was responsible for the up-regulation of the purple allele BjMYB113a and high accumulation of anthocyanin in the purple cultivar. The up-regulation of BjMYB113a increased the expression of genes in the anthocyanin biosynthesis pathway including BjCHS, BjF3H, BjF3’H, BjDFR, BjANS and BjUGFT, and consequently led to high accumulation of anthocyanin. However, the up-regulation of BjMYB113 was compromised by the insertion of 1,033-bp in 3’region of the allele BjMYB113c. Conclusions Our results contribute to a better understanding of the genetics and evolution of the BjMYB113 gene controlling purple leaves and provide useful information for further breeding programs of mustard.


Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 394 ◽  
Author(s):  
Enerand Mackon ◽  
Guibeline Charlie Jeazet Dongho Epse Mackon ◽  
Yafei Ma ◽  
Muhammad Haneef Kashif ◽  
Niyaz Ali ◽  
...  

Anthocyanins are antioxidants used as natural colorants and are beneficial to human health. Anthocyanins contribute to reactive oxygen species detoxification and sustain plant growth and development under different environmental stresses. They are phenolic compounds that are broadly distributed in nature and are responsible for a wide range of attractive coloration in many plant organs. Anthocyanins are found in various parts of plants such as flowers, leaves, stems, shoots, and grains. Considering their nutritional and health attributes, anthocyanin-enriched rice or pigmented rice cultivars are a possible alternative to reduce malnutrition around the globe. Anthocyanin biosynthesis and storage in rice are complex processes in which several structural and regulatory genes are involved. In recent years, significant progress has been achieved in the molecular and genetic mechanism of anthocyanins, and their synthesis is of great interest to researchers and the scientific community. However, limited studies have reported anthocyanin synthesis, transportation, and environmental conditions that can hinder anthocyanin production in rice. Rice is a staple food around the globe, and further research on anthocyanin in rice warrants more attention. In this review, metabolic and pre-biotic activities, the underlying transportation, and storage mechanisms of anthocyanins in rice are discussed in detail. This review provides potential information for the food industry and clues for rice breeding and genetic engineering of rice.


2021 ◽  
Vol 22 (6) ◽  
pp. 3026
Author(s):  
Xieyu Li ◽  
Fangxin Xiang ◽  
Wei Han ◽  
Bingqing Qie ◽  
Rui Zhai ◽  
...  

The N-terminal of Myc-like basic helix-loop-helix transcription factors (bHLH TFs) contains an interaction domain, namely the MYB-interacting region (MIR), which interacts with the R2R3-MYB proteins to regulate genes involved in the anthocyanin biosynthetic pathway. However, the functions of MIR-domain bHLHs in this pathway are not fully understood. In this study, PbbHLH2 containing the MIR-domain was identified and its function investigated. The overexpression of PbbHLH2 in ”Zaosu” pear peel increased the anthocyanin content and the expression levels of late biosynthetic genes. Bimolecular fluorescence complementation showed that PbbHLH2 interacted with R2R3-MYB TFs PbMYB9, 10, and 10b in onion epidermal cells and confirmed that MIR-domain plays important roles in the interaction between the MIR-domain bHLH and R2R3-MYB TFs. Moreover, PbbHLH2 bound and activated the dihydroflavonol reductase promoter in yeast one-hybrid (Y1H) and dual-luciferase assays. Taken together these results suggested that the MIR domain of PbbHLH2 regulated anthocyanin biosynthesis in pear fruit peel.


2018 ◽  
Author(s):  
Xi Ou Xiao ◽  
Wen qiu Lin ◽  
Ke Li ◽  
Xue Feng Feng ◽  
Hui Jin ◽  
...  

We obtained a white-peel eggplant (L6-5) by EMS mutation in our previous study, whose total anthocyanin content was significantly decreased as compared with that of wild-type (WT). To analyse the anthocyanin biosynthesis mechanism in eggplants, we analysed the eggplant peel by RNA-seq in this study. The transcript results revealed upregulation of 465 genes and downregulation of 525 genes in L6-5 as compared with the WT eggplant. A total of 11 anthocyanin biosynthesis structure genes were significantly downregulated in L6-5 as compared with that in WT. Meanwhile, on the basis of the RT-PCR results of four natural eggplant cultivars, the expression pattern of 11 anthocyanin biosynthesis structure genes was consistent with the anthocyanin content. Thus, we speculated the anthocyanin biosynthesis pathway in eggplant peel. The transcript and RT-PCR results suggested positive regulation of MYB1, MYB108 and TTG8 and negative regulation of bHLH36 in anthocyanin biosynthesis. This study enhanced our cumulative knowledge about anthocyanin biosynthesis in eggplant peels.


Author(s):  
Xiaoyu Su ◽  
Zhenbao Jia ◽  
Fei Tao ◽  
Jiamin Shen ◽  
Jingwen Xu ◽  
...  

Phytochemical-enriched edible greens, sweet potato leaves (Ipomoea batatas L.), have become popular due to potential health benefits. However, the phytochemical contents in sweet potato leaves and their subsequent change over harvest stages and growth condition are mostly unknown. In this study, the anthocyanin profile and content in leaves of four sweet potato cultivars, i.e., white-skinned and white-fleshed Bonita, red-skinned and orange-fleshed Beauregard, red-skinned and white-fleshed Murasaki and purple-skinned and purple-fleshed P40, were evaluated. Fourteen anthocyanins were isolated and identified by HPLC-MSI/MS. The most abundant was cyanidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, which comprised up to 20% of the total anthocyanins. Of the young leaves (1st and 2nd slip cuttings), Bonita contained the highest anthocyanin content followed by P40. Of the mature leaves (vine stage), Beauregard had the greatest anthocyanin (592.5 ± 86.4 mg/kg DW) and total phenolic (52.2 ± 3 mg GAE/g DW). It should be noted that the lowest anthocyanin and total phenolic content of shoots were found in P40, while tubers of P40 contain the highest content of each. Furthermore, the increase in leaf anthocyanin content over the growth stages that was observed in three of the cultivars but not in P40. No significant difference of anthocyanin content was found in Beauregard leaves grown in the high tunnels when compared with that in the open field. This study demonstrated for the first time that anthocyanin levels were significantly changed in response to various growth stages but not high tunnel condition, indicating that the effect of anthocyanin biosynthesis in sweet potato leaves is highly variable and genotype specific.


Author(s):  
Emine Ece Mercan ◽  
Mehtap Şahin-Çevik

Abstract Anthocyanins are water-soluble pigments responsible for red, pink, purple or blue coloration in the flesh and/or skin of apple fruit. Since consumers prefer anthocyanin rich fruits due to their health benefits, anthocyanin content is an important trait for marketability of apples. Synthesis and accumulation of anthocyanins are controlled by environmental and genetic factors such as transcription factors (TFs). Two-repeat (R2R3) MYB TFs are involved in the regulation of anthocyanin biosynthesis in plants. In this study, the expression of the MdMYBA and MdMYB3 genes encoding R2R3 type MYB TFs were analyzed in apple cultivars with fruit skin color from green to dark red at different growth stages. Fruit samples were collected from “Scarlet Spur”, “Galaxy Gala”, Golden Delicious” “Granny Smith” apple cultivars with dark red, light red, yellow and green fruits, respectively, at four different time periods after full-bloom. Total RNA was isolated from the peel of the collected fruits and the expression of the MdMYBA and MdMYB3 genes was analyzed by real-time RT-PCR. The expression of the MdMYBA gene started to increase at 92 DAFB and thereafter in red-skin apples; however, no expression was observed at any time points in yellow or green-skin apple cultivars. On the other hand, the MdMYB3 gene was expressed in red-skin and yellow-skin apple cultivars starting at 55 DAFB, but no expression was observed in green apple cultivar at any time of fruit maturation. The expression levels of the MdMYBA and MdMYB3 genes varied in apple fruits with different skin coloration indicating that they play a role regulation of the anthocyanin biosynthesis in apple cultivars during fruit maturation.


Horticulturae ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 15 ◽  
Author(s):  
Ivan Simko

Lettuce harvested at the baby leaf stage is a popular component of mixed salads in ready-to-use packages. Little is known, however, about response of baby leaf lettuce to nitrogen (N), phosphorus (P), and potassium (K) fertilization. Eight lettuce accessions were subjected to five fertilization treatments to investigate genetic differences in reaction to N, P, and K fertilization. The control treatment provided optimal levels of macronutrients for plant growth, while other treatments deprived plants of either N, P, or K. Potassium deprivation had no obvious effect on plant weight or composition, apart from substantially decreased potassium content. Nitrogen and phosphorus deprivations, however, extensively decreased fresh weight and affected plant composition. Phosphorus and nitrogen deprivation considerably increased anthocyanin content in red-colored accessions, but anthocyanin was decreased in dark green-colored accessions, indicating differences in regulation of anthocyanin biosynthesis. Correlations between fresh weight, chlorophyll, anthocyanin, nitrogen, phosphorus, and potassium content were substantially affected by selection of datasets used for analyses; some relationships were revealed when analyzed separately by individual treatments, while others were more likely to be detected when analyzed by individual accessions. Absolute (ΔABS) and relative (2ΔREL) parameters described in this study were suitable for detecting over- and underperforming accessions. The ΔABS identified the absolute Lb-fold (logarithm to the base of 2, binary logarithm) change in performance of an accession in a treatment as compared to its performance in control conditions. The 2ΔREL parameter showed relative Lb-fold change for an accession as compared to the overall mean of ΔABS values of all accessions tested in control and treatment conditions.


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