Betalain

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Reinhold Carle - One of the best experts on this subject based on the ideXlab platform.

  • Betalain Pigments and Color Quality
    2008
    Co-Authors: Florian C Stintzing, Kirsten M Herbach, Markus R. Mosshammer, Florian Kugler, Reinhold Carle
    Abstract:

    Betalain pigments are responsible for imparting yellow, orange, red and purple colors to flowers, grains, vegetables and fruits of a comparatively limited number of species all belonging to the suborder Chenopodiniae within the Caryophyllales (1). Due to their limited distribution and the even more restricted occurrence in edible plants, Betalains have received little attention. Currently, however, Betalains are witnessing a renewed interest, especially in the food sector (2). Among the presently available food sources, red beet represents the most widespread Betalain crop: It exhibits high pigment contents and is easy to grow so that it is well introduced on the market. Right now, alternative Betalain sources are receiving consideration, such as yellow beet, red-purple pitayas or cactus pears complementing the narrow color range of red beets. In order to fully benefit from the potential of Betalains, the present review will describe the interrelationships between color and structure of both betacyanins and betaxanthins and will also discuss how these principles govern the appearance of the respective food.

  • Stability of yellow-orange cactus pear (Opuntia ficus-indica [L.] Mill. cv. ‘Gialla’) Betalains as affected by the juice matrix and selected food additives
    European Food Research and Technology, 2007
    Co-Authors: Markus R. Mosshammer, Florian C Stintzing, Michael Rohe, Reinhold Carle
    Abstract:

    The impact of added ascorbic, isoascorbic, and citric acid on heat stability of cactus pear Betalains was investigated at pH 4 and 6, respectively. To assess the influence of cactus pear juice matrix compounds such as sugars, organic acids, amino acids, and pectic substances on pigment stability, juice and purified pigment preparations derived therefrom were assayed separately. Immediately after heating at 85 °C for 1 h and a 24 h cool storage period, Betalain retention, betanin and proline-betaxanthin isomerisation as well as overall colour changes were determined. Pigment stability and colour characteristics depended on type and concentration of the respective additive as well as on pH conditions. Interestingly, the stabilising effects of the additives under investigation were less pronounced in matrix-free pigment preparations compared to juice samples. Maximum pigment retention amounting to 79% was obtained when 0.1% citric acid was added to the juice at pH 6. For the first time, formation of 2-decarboxy-betanin upon thermal treatment of yellow-orange cactus pear juice being more distinct at pH 4 as compared to pH 6 is reported.

  • Betalain stability and degradation structural and chromatic aspects
    Journal of Food Science, 2006
    Co-Authors: Kirsten M Herbach, Florian C Stintzing, Reinhold Carle
    Abstract:

    In recent years, food coloring with artificial colorants has been increasingly disapproved by consumers. In return, application of coloring foodstuffs, among them Betalain-containing fruits and vegetables, has gained importance for the food industry. As commonly true for natural pigments, Betalains are afflicted with inferior stability compared to synthetic dyes. Especially temperature, oxygen, and light are known to exhibit detrimental effects on Betalain integrity, while certain antioxidants and chelating agents may act as stabilizers. Only recently, several studies expanded the knowledge on Betalain degradation pathways, especially focusing on betacyanin decomposition. Additionally, new findings on stability and stabilization of Betalains in cactus fruit juices extended the application range of Betalainic foodstuffs. Focusing on betacyanins, the present review discusses Betalain degradation mechanisms and provides a survey of compounds and conditions governing Betalain stability in a beneficial or an unfavorable way. Finally, strategies for maintaining the chromatic properties and tinctorial strength of Betalain-based juices and pigment preparations as well as tools for color modulation by targeted betacyanin degradation are discussed.

  • Betalain Stability and Degradation—Structural and Chromatic Aspects
    Journal of Food Science, 2006
    Co-Authors: Kirsten M Herbach, Florian C Stintzing, Reinhold Carle
    Abstract:

    In recent years, food coloring with artificial colorants has been increasingly disapproved by consumers. In return, application of coloring foodstuffs, among them Betalain-containing fruits and vegetables, has gained importance for the food industry. As commonly true for natural pigments, Betalains are afflicted with inferior stability compared to synthetic dyes. Especially temperature, oxygen, and light are known to exhibit detrimental effects on Betalain integrity, while certain antioxidants and chelating agents may act as stabilizers. Only recently, several studies expanded the knowledge on Betalain degradation pathways, especially focusing on betacyanin decomposition. Additionally, new findings on stability and stabilization of Betalains in cactus fruit juices extended the application range of Betalainic foodstuffs. Focusing on betacyanins, the present review discusses Betalain degradation mechanisms and provides a survey of compounds and conditions governing Betalain stability in a beneficial or an unfavorable way. Finally, strategies for maintaining the chromatic properties and tinctorial strength of Betalain-based juices and pigment preparations as well as tools for color modulation by targeted betacyanin degradation are discussed.

  • Urinary pharmacokinetics of Betalains following consumption of red beet juice in healthy humans
    Pharmacological Research, 2005
    Co-Authors: Thomas Frank, Florian C Stintzing, Reinhold Carle, Irmgard Bitsch, Daniela Quaas, G. Strass, R. Bitsch, Michael Netzel
    Abstract:

    The aim of the present pilot study was to characterise the renal elimination of Betalains after consumption of red beet juice (RBJ). Six healthy, non-smoking female volunteers were given a single oral dose of either 500 mL of a commercial RBJ containing 362.7 mg of Betalains and 500 mL of tap water, respectively, in a sequential manner. Urine was collected in intervals up to 24 h post-dose. Renal excretion of Betalains was determined spectrophotometrically and quantified as betanin-equivalents. In addition, the identity of individual compounds was confirmed by HPLC coupled with diode-array detection and positive ion electrospray mass spectrometry, respectively. The amount (mean ± S.D.) of intact Betalains (betanin and isobetanin) recovered in urine was 1001 ± 273 μg corresponding to 0.28 ± 0.08% of the administered dose. Maximum excretion rates were observed after a median tmax,R of 3.0 h (range 2.5-8.0 h) amounting to 91.7 ± 30.1 μg/h. The terminal elimination rate constant (λz) and the corresponding half-life were 0.097 ± 0.021 h-1 and 7.43 ± 1.47 h, respectively. Using the λz estimates obtained the expected total Betalain amount excreted in urine was 1228 ± 291 μg. Based on the results obtained it is assumed that either the bioavailability of the Betalains is low or that renal clearance is a minor route of systemic elimination for these compounds. The urinary excretion rates of unmetabolised Betalains were fast and appeared to be monoexponential suggesting a one-compartment model. In order to get a more complete picture of the pharmacokinetics and health-promoting properties of red beet Betalains, quantitative data on Betalain bioavailability should include measurements of unchanged compounds and their corresponding metabolites in plasma, urine and bile.

Jean Pierre Zrÿd - One of the best experts on this subject based on the ideXlab platform.

  • characterization and functional identification of a novel plant 4 5 extradiol dioxygenase involved in Betalain pigment biosynthesis in portulaca grandiflora
    Plant Physiology, 2004
    Co-Authors: Laurent Christinet, Frederic X Burdet, Maia Zaiko, Ursula Hinz, Jean Pierre Zrÿd
    Abstract:

    Betalains are pigments that replace anthocyanins in the majority of families of the plant order Caryophyllales. Betalamic acid is the common chromophore of Betalains. The key enzyme of the Betalain biosynthetic pathway is an extradiol dioxygenase that opens the cyclic ring of dihydroxy-phenylalanine (DOPA) between carbons 4 and 5, thus producing an unstable seco-DOPA that rearranges nonenzymatically to betalamic acid. A gene for a 4,5-DOPA-dioxygenase has already been isolated from the fungus Amanita muscaria, but no homolog was ever found in plants. To identify the plant gene, we constructed subtractive libraries between different colored phenotypes of isogenic lines of Portulaca grandiflora (Portulacaceae) and between different stages of flower bud formation. Using in silico analysis of differentially expressed cDNAs, we identified a candidate showing strong homology at the level of translated protein with the LigB domain present in several bacterial extradiol 4,5-dioxygenases. The gene was expressed only in colored flower petals. The function of this gene in the Betalain biosynthetic pathway was confirmed by biolistic genetic complementation in white petals of P. grandiflora genotypes lacking the gene for color formation. This gene named DODA is the first characterized member of a novel family of plant dioxygenases phylogenetically distinct from Amanita sp. DOPA-dioxygenase. Homologs of DODA are present not only in Betalain-producing plants but also, albeit with some changes near the catalytic site, in other angiosperms and in the bryophyte Physcomitrella patens. These homologs are part of a novel conserved plant gene family probably involved in aromatic compound metabolism.

  • Betalain producing cell cultures ofBeta vulgaris L. var. bikores monogerm (red beet)
    In Vitro – Plant, 1992
    Co-Authors: Roland R. Leathers, Catherine Davin, Jean Pierre Zrÿd
    Abstract:

    The Betalains are a class of natural pigments comprising the yellow betaxanthins and the violet betacyanins. Callus lines developed from Beta vulgaris , L. var. bikores monogerm exhibited cell colors ranging from white/green (nonpigmented) through yellow, orange, red, and violet and were representative of all Betalain pigments found in the whole plant. The Betalains have gained particular interest from the food industry as potential natural alternatives to synthetic food colorants in use today. Red beet extracts (E162), which contain significant amounts of the betacyanins, are currently used in products such as yogurts and ice creams. We describe here the characteristics of culture growth and Betalain production for cell suspensions derived from the orange (predominantly betaxanthin-producing) and violet (betacyanin producing) callus lines. The major factors affecting Betalain biosynthesis in both cultured and whole plant tissues are reviewed.

  • Betalain producing cell cultures of beta vulgaris l var bikores monogerm red beet
    In Vitro Cellular & Developmental Biology – Plant, 1992
    Co-Authors: Roland R. Leathers, Catherine Davin, Jean Pierre Zrÿd
    Abstract:

    The Betalains are a class of natural pigments comprising the yellow betaxanthins and the violet betacyanins. Callus lines developed fromBeta vulgaris, L. var. bikores monogerm exhibited cell colors ranging from white/green (nonpigmented) through yellow, orange, red, and violet and were representative of all Betalain pigments found in the whole plant. The Betalains have gained particular interest from the food industry as potential natural alternatives to synthetic food colorants in use today. Red beet extracts (E162), which contain significant amounts of the betacyanins, are currently used in products such as yogurts and ice creams. We describe here the characteristics of culture growth and Betalain production for cell suspensions derived from the orange (predominantly betaxanthin-producing) and violet (betacyanin producing) callus lines. The major factors affecting Betalain biosynthesis in both cultured and whole plant tissues are reviewed.

Asaph Aharoni - One of the best experts on this subject based on the ideXlab platform.

  • advances and future directions in Betalain metabolic engineering
    New Phytologist, 2019
    Co-Authors: Guy Polturak, Asaph Aharoni
    Abstract:

    SUMMARY: Betalains are nitrogenous red and yellow pigments found in a single order of plants, the Caryophyllales, and in some higher fungi. They are responsible for the colors observed in many ornamental plants, as well as in various food products, where they are used as natural colorants. Their nutritional properties and attractive colors make them an appealing target for metabolic engineering. This is further heightened by the limited availability of natural Betalain sources, arising from their relative scarcity in the plant kingdom, particularly in edible plants. Recent progress in decoding their biosynthetic pathway has facilitated stable heterologous production of Betalains in several plant and microbial systems. Here, we provide a brief review of recent advances and discuss current approaches and possible future directions in Betalain metabolic engineering, including expanding the chemical diversity of Betalains and increasing their yield, exploring new host organisms for their heterologous production, and engineering their secretion from the cell.

  • la vie en rose biosynthesis sources and applications of Betalain pigments
    Molecular Plant, 2018
    Co-Authors: Guy Polturak, Asaph Aharoni
    Abstract:

    Abstract Betalains are tyrosine-derived red-violet and yellow pigments found exclusively in plants of the Caryophyllales order, which have drawn both scientific and economic interest. Nevertheless, research into Betalain chemistry, biochemistry, and function has been limited as comparison with other major classes of plant pigments such as anthocyanins and carotenoids. The core biosynthetic pathway of this pigment class has only been fully elucidated in the past few years, opening up the possibility for Betalain pigment engineering in plants and microbes. In this review, we discuss Betalain metabolism in light of recent advances in the field, with a current survey of characterized genes and enzymes that take part in Betalain biosynthesis, catabolism, and transcriptional regulation, and an outlook of what is yet to be discovered. A broad view of currently used and potential new sources for Betalains, including utilization of natural sources or metabolic engineering, is provided together with a summary of potential applications of Betalains in research and commercial use.

  • transcriptome and metabolic profiling provides insights into Betalain biosynthesis and evolution in mirabilis jalapa
    Molecular Plant, 2018
    Co-Authors: Guy Polturak, Noam Grossman, Ilana Rogachev, Uwe Heinig, Maor Battat, Dena Leshkowitz, Sergey Malitsky, Asaph Aharoni
    Abstract:

    Betalains are tyrosine-derived pigments that occur solely in one plant order, the Caryophyllales, where they largely replace the anthocyanins in a mutually exclusive manner. In this study, we conducted multi-species transcriptome and metabolic profiling in Mirabilis jalapa and additional Betalain-producing species to identify candidate genes possibly involved in Betalain biosynthesis. Among the candidates identified, Betalain-related cytochrome P450 and glucosyltransferase-type genes, which catalyze tyrosine hydroxylation or (hydroxy)cinnamoyl-glucose formation, respectively, were further functionally characterized. We detected the expression of genes in the flavonoid/anthocyanin biosynthetic pathways as well as their metabolite intermediates in Betalain-accumulating M. jalapa flowers, and found that the anthocyanin-related gene ANTHOCYANIDIN SYNTHASE (MjANS) is highly expressed in the Betalain-accumulating petals. However, it appears that MjANS contains a significant deletion in a region spanning the corresponding enzyme active site. These findings provide novel insights into Betalain biosynthesis and a possible explanation for how anthocyanins have been lost in this plant species. Our study also implies a complex, non-uniform history for the loss of anthocyanin production across Betalain producers, previously assumed to be strictly due to diminished expression of anthocyanin-related genes.

  • engineered gray mold resistance antioxidant capacity and pigmentation in Betalain producing crops and ornamentals
    Proceedings of the National Academy of Sciences of the United States of America, 2017
    Co-Authors: Guy Polturak, Noam Grossman, David Velacorcia, Yonghui Dong, Adi Nudel, Margarita Pliner, Maggie Levy, Ilana Rogachev, Asaph Aharoni
    Abstract:

    Betalains are tyrosine-derived red-violet and yellow plant pigments known for their antioxidant activity, health-promoting properties, and wide use as food colorants and dietary supplements. By coexpressing three genes of the recently elucidated Betalain biosynthetic pathway, we demonstrate the heterologous production of these pigments in a variety of plants, including three major food crops: tomato, potato, and eggplant, and the economically important ornamental petunia. Combinatorial expression of Betalain-related genes also allowed the engineering of tobacco plants and cell cultures to produce a palette of unique colors. Furthermore, Betalain-producing tobacco plants exhibited significantly increased resistance toward gray mold (Botrytis cinerea), a pathogen responsible for major losses in agricultural produce. Heterologous production of Betalains is thus anticipated to enable biofortification of essential foods, development of new ornamental varieties, and innovative sources for commercial Betalain production, as well as utilization of these pigments in crop protection.

  • elucidation of the first committed step in Betalain biosynthesis enables the heterologous engineering of Betalain pigments in plants
    New Phytologist, 2016
    Co-Authors: Guy Polturak, Noam Grossman, Margarita Pliner, Ilana Rogachev, Dario Breitel, Alejandro Sarrionperdigones, Efrat Weithorn, Diego Orzaez, Antonio Granell, Asaph Aharoni
    Abstract:

    Summary Betalains are tyrosine-derived red-violet and yellow pigments, found in plants only of the Caryophyllales order. Although much progress has been made in recent years in the understanding of the Betalain biosynthetic process, many questions remain open with regards to several of the proposed steps in the pathway. Most conspicuous by its absence is the characterization of the first committed step in the pathway, namely the 3-hydroxylation of tyrosine to form l-3,4-dihydroxyphenylalanine (l-DOPA). We used transcriptome analysis of the Betalain-producing plants red beet (Beta vulgaris) and four o'clocks (Mirabilis jalapa) to identify a novel, Betalain-related cytochrome P450-type gene, CYP76AD6, and carried out gene silencing and recombinant expression assays in Nicotiana benthamiana and yeast cells to examine its functionality. l-DOPA formation in red beet was found to be redundantly catalyzed by CYP76AD6 together with a known Betalain-related enzyme, CYP76AD1, which was previously thought to only catalyze a succeeding step in the pathway. While CYP76AD1 catalyzes both l-DOPA formation and its subsequent conversion to cyclo-DOPA, CYP76AD6 uniquely exhibits only tyrosine hydroxylase activity. The new findings enabled us to metabolically engineer entirely red-pigmented tobacco plants through heterologous expression of three genes taking part in the fully decoded Betalain biosynthetic pathway.

Florian C Stintzing - One of the best experts on this subject based on the ideXlab platform.

  • Betalain Pigments and Color Quality
    2008
    Co-Authors: Florian C Stintzing, Kirsten M Herbach, Markus R. Mosshammer, Florian Kugler, Reinhold Carle
    Abstract:

    Betalain pigments are responsible for imparting yellow, orange, red and purple colors to flowers, grains, vegetables and fruits of a comparatively limited number of species all belonging to the suborder Chenopodiniae within the Caryophyllales (1). Due to their limited distribution and the even more restricted occurrence in edible plants, Betalains have received little attention. Currently, however, Betalains are witnessing a renewed interest, especially in the food sector (2). Among the presently available food sources, red beet represents the most widespread Betalain crop: It exhibits high pigment contents and is easy to grow so that it is well introduced on the market. Right now, alternative Betalain sources are receiving consideration, such as yellow beet, red-purple pitayas or cactus pears complementing the narrow color range of red beets. In order to fully benefit from the potential of Betalains, the present review will describe the interrelationships between color and structure of both betacyanins and betaxanthins and will also discuss how these principles govern the appearance of the respective food.

  • Stability of yellow-orange cactus pear (Opuntia ficus-indica [L.] Mill. cv. ‘Gialla’) Betalains as affected by the juice matrix and selected food additives
    European Food Research and Technology, 2007
    Co-Authors: Markus R. Mosshammer, Florian C Stintzing, Michael Rohe, Reinhold Carle
    Abstract:

    The impact of added ascorbic, isoascorbic, and citric acid on heat stability of cactus pear Betalains was investigated at pH 4 and 6, respectively. To assess the influence of cactus pear juice matrix compounds such as sugars, organic acids, amino acids, and pectic substances on pigment stability, juice and purified pigment preparations derived therefrom were assayed separately. Immediately after heating at 85 °C for 1 h and a 24 h cool storage period, Betalain retention, betanin and proline-betaxanthin isomerisation as well as overall colour changes were determined. Pigment stability and colour characteristics depended on type and concentration of the respective additive as well as on pH conditions. Interestingly, the stabilising effects of the additives under investigation were less pronounced in matrix-free pigment preparations compared to juice samples. Maximum pigment retention amounting to 79% was obtained when 0.1% citric acid was added to the juice at pH 6. For the first time, formation of 2-decarboxy-betanin upon thermal treatment of yellow-orange cactus pear juice being more distinct at pH 4 as compared to pH 6 is reported.

  • Betalain stability and degradation structural and chromatic aspects
    Journal of Food Science, 2006
    Co-Authors: Kirsten M Herbach, Florian C Stintzing, Reinhold Carle
    Abstract:

    In recent years, food coloring with artificial colorants has been increasingly disapproved by consumers. In return, application of coloring foodstuffs, among them Betalain-containing fruits and vegetables, has gained importance for the food industry. As commonly true for natural pigments, Betalains are afflicted with inferior stability compared to synthetic dyes. Especially temperature, oxygen, and light are known to exhibit detrimental effects on Betalain integrity, while certain antioxidants and chelating agents may act as stabilizers. Only recently, several studies expanded the knowledge on Betalain degradation pathways, especially focusing on betacyanin decomposition. Additionally, new findings on stability and stabilization of Betalains in cactus fruit juices extended the application range of Betalainic foodstuffs. Focusing on betacyanins, the present review discusses Betalain degradation mechanisms and provides a survey of compounds and conditions governing Betalain stability in a beneficial or an unfavorable way. Finally, strategies for maintaining the chromatic properties and tinctorial strength of Betalain-based juices and pigment preparations as well as tools for color modulation by targeted betacyanin degradation are discussed.

  • Betalain Stability and Degradation—Structural and Chromatic Aspects
    Journal of Food Science, 2006
    Co-Authors: Kirsten M Herbach, Florian C Stintzing, Reinhold Carle
    Abstract:

    In recent years, food coloring with artificial colorants has been increasingly disapproved by consumers. In return, application of coloring foodstuffs, among them Betalain-containing fruits and vegetables, has gained importance for the food industry. As commonly true for natural pigments, Betalains are afflicted with inferior stability compared to synthetic dyes. Especially temperature, oxygen, and light are known to exhibit detrimental effects on Betalain integrity, while certain antioxidants and chelating agents may act as stabilizers. Only recently, several studies expanded the knowledge on Betalain degradation pathways, especially focusing on betacyanin decomposition. Additionally, new findings on stability and stabilization of Betalains in cactus fruit juices extended the application range of Betalainic foodstuffs. Focusing on betacyanins, the present review discusses Betalain degradation mechanisms and provides a survey of compounds and conditions governing Betalain stability in a beneficial or an unfavorable way. Finally, strategies for maintaining the chromatic properties and tinctorial strength of Betalain-based juices and pigment preparations as well as tools for color modulation by targeted betacyanin degradation are discussed.

  • Urinary pharmacokinetics of Betalains following consumption of red beet juice in healthy humans
    Pharmacological Research, 2005
    Co-Authors: Thomas Frank, Florian C Stintzing, Reinhold Carle, Irmgard Bitsch, Daniela Quaas, G. Strass, R. Bitsch, Michael Netzel
    Abstract:

    The aim of the present pilot study was to characterise the renal elimination of Betalains after consumption of red beet juice (RBJ). Six healthy, non-smoking female volunteers were given a single oral dose of either 500 mL of a commercial RBJ containing 362.7 mg of Betalains and 500 mL of tap water, respectively, in a sequential manner. Urine was collected in intervals up to 24 h post-dose. Renal excretion of Betalains was determined spectrophotometrically and quantified as betanin-equivalents. In addition, the identity of individual compounds was confirmed by HPLC coupled with diode-array detection and positive ion electrospray mass spectrometry, respectively. The amount (mean ± S.D.) of intact Betalains (betanin and isobetanin) recovered in urine was 1001 ± 273 μg corresponding to 0.28 ± 0.08% of the administered dose. Maximum excretion rates were observed after a median tmax,R of 3.0 h (range 2.5-8.0 h) amounting to 91.7 ± 30.1 μg/h. The terminal elimination rate constant (λz) and the corresponding half-life were 0.097 ± 0.021 h-1 and 7.43 ± 1.47 h, respectively. Using the λz estimates obtained the expected total Betalain amount excreted in urine was 1228 ± 291 μg. Based on the results obtained it is assumed that either the bioavailability of the Betalains is low or that renal clearance is a minor route of systemic elimination for these compounds. The urinary excretion rates of unmetabolised Betalains were fast and appeared to be monoexponential suggesting a one-compartment model. In order to get a more complete picture of the pharmacokinetics and health-promoting properties of red beet Betalains, quantitative data on Betalain bioavailability should include measurements of unchanged compounds and their corresponding metabolites in plasma, urine and bile.

Guy Polturak - One of the best experts on this subject based on the ideXlab platform.

  • advances and future directions in Betalain metabolic engineering
    New Phytologist, 2019
    Co-Authors: Guy Polturak, Asaph Aharoni
    Abstract:

    SUMMARY: Betalains are nitrogenous red and yellow pigments found in a single order of plants, the Caryophyllales, and in some higher fungi. They are responsible for the colors observed in many ornamental plants, as well as in various food products, where they are used as natural colorants. Their nutritional properties and attractive colors make them an appealing target for metabolic engineering. This is further heightened by the limited availability of natural Betalain sources, arising from their relative scarcity in the plant kingdom, particularly in edible plants. Recent progress in decoding their biosynthetic pathway has facilitated stable heterologous production of Betalains in several plant and microbial systems. Here, we provide a brief review of recent advances and discuss current approaches and possible future directions in Betalain metabolic engineering, including expanding the chemical diversity of Betalains and increasing their yield, exploring new host organisms for their heterologous production, and engineering their secretion from the cell.

  • la vie en rose biosynthesis sources and applications of Betalain pigments
    Molecular Plant, 2018
    Co-Authors: Guy Polturak, Asaph Aharoni
    Abstract:

    Abstract Betalains are tyrosine-derived red-violet and yellow pigments found exclusively in plants of the Caryophyllales order, which have drawn both scientific and economic interest. Nevertheless, research into Betalain chemistry, biochemistry, and function has been limited as comparison with other major classes of plant pigments such as anthocyanins and carotenoids. The core biosynthetic pathway of this pigment class has only been fully elucidated in the past few years, opening up the possibility for Betalain pigment engineering in plants and microbes. In this review, we discuss Betalain metabolism in light of recent advances in the field, with a current survey of characterized genes and enzymes that take part in Betalain biosynthesis, catabolism, and transcriptional regulation, and an outlook of what is yet to be discovered. A broad view of currently used and potential new sources for Betalains, including utilization of natural sources or metabolic engineering, is provided together with a summary of potential applications of Betalains in research and commercial use.

  • transcriptome and metabolic profiling provides insights into Betalain biosynthesis and evolution in mirabilis jalapa
    Molecular Plant, 2018
    Co-Authors: Guy Polturak, Noam Grossman, Ilana Rogachev, Uwe Heinig, Maor Battat, Dena Leshkowitz, Sergey Malitsky, Asaph Aharoni
    Abstract:

    Betalains are tyrosine-derived pigments that occur solely in one plant order, the Caryophyllales, where they largely replace the anthocyanins in a mutually exclusive manner. In this study, we conducted multi-species transcriptome and metabolic profiling in Mirabilis jalapa and additional Betalain-producing species to identify candidate genes possibly involved in Betalain biosynthesis. Among the candidates identified, Betalain-related cytochrome P450 and glucosyltransferase-type genes, which catalyze tyrosine hydroxylation or (hydroxy)cinnamoyl-glucose formation, respectively, were further functionally characterized. We detected the expression of genes in the flavonoid/anthocyanin biosynthetic pathways as well as their metabolite intermediates in Betalain-accumulating M. jalapa flowers, and found that the anthocyanin-related gene ANTHOCYANIDIN SYNTHASE (MjANS) is highly expressed in the Betalain-accumulating petals. However, it appears that MjANS contains a significant deletion in a region spanning the corresponding enzyme active site. These findings provide novel insights into Betalain biosynthesis and a possible explanation for how anthocyanins have been lost in this plant species. Our study also implies a complex, non-uniform history for the loss of anthocyanin production across Betalain producers, previously assumed to be strictly due to diminished expression of anthocyanin-related genes.

  • engineered gray mold resistance antioxidant capacity and pigmentation in Betalain producing crops and ornamentals
    Proceedings of the National Academy of Sciences of the United States of America, 2017
    Co-Authors: Guy Polturak, Noam Grossman, David Velacorcia, Yonghui Dong, Adi Nudel, Margarita Pliner, Maggie Levy, Ilana Rogachev, Asaph Aharoni
    Abstract:

    Betalains are tyrosine-derived red-violet and yellow plant pigments known for their antioxidant activity, health-promoting properties, and wide use as food colorants and dietary supplements. By coexpressing three genes of the recently elucidated Betalain biosynthetic pathway, we demonstrate the heterologous production of these pigments in a variety of plants, including three major food crops: tomato, potato, and eggplant, and the economically important ornamental petunia. Combinatorial expression of Betalain-related genes also allowed the engineering of tobacco plants and cell cultures to produce a palette of unique colors. Furthermore, Betalain-producing tobacco plants exhibited significantly increased resistance toward gray mold (Botrytis cinerea), a pathogen responsible for major losses in agricultural produce. Heterologous production of Betalains is thus anticipated to enable biofortification of essential foods, development of new ornamental varieties, and innovative sources for commercial Betalain production, as well as utilization of these pigments in crop protection.

  • elucidation of the first committed step in Betalain biosynthesis enables the heterologous engineering of Betalain pigments in plants
    New Phytologist, 2016
    Co-Authors: Guy Polturak, Noam Grossman, Margarita Pliner, Ilana Rogachev, Dario Breitel, Alejandro Sarrionperdigones, Efrat Weithorn, Diego Orzaez, Antonio Granell, Asaph Aharoni
    Abstract:

    Summary Betalains are tyrosine-derived red-violet and yellow pigments, found in plants only of the Caryophyllales order. Although much progress has been made in recent years in the understanding of the Betalain biosynthetic process, many questions remain open with regards to several of the proposed steps in the pathway. Most conspicuous by its absence is the characterization of the first committed step in the pathway, namely the 3-hydroxylation of tyrosine to form l-3,4-dihydroxyphenylalanine (l-DOPA). We used transcriptome analysis of the Betalain-producing plants red beet (Beta vulgaris) and four o'clocks (Mirabilis jalapa) to identify a novel, Betalain-related cytochrome P450-type gene, CYP76AD6, and carried out gene silencing and recombinant expression assays in Nicotiana benthamiana and yeast cells to examine its functionality. l-DOPA formation in red beet was found to be redundantly catalyzed by CYP76AD6 together with a known Betalain-related enzyme, CYP76AD1, which was previously thought to only catalyze a succeeding step in the pathway. While CYP76AD1 catalyzes both l-DOPA formation and its subsequent conversion to cyclo-DOPA, CYP76AD6 uniquely exhibits only tyrosine hydroxylase activity. The new findings enabled us to metabolically engineer entirely red-pigmented tobacco plants through heterologous expression of three genes taking part in the fully decoded Betalain biosynthetic pathway.