Betalain Production Research Articles

Correction to: Production of betalains in plant cell and organ cultures: a review

Correction to: Production of betalains in plant cell and organ cultures: a review

Production of betalains in plant cell and organ cultures: a review

Production of betalains in plant cell and organ cultures: a review

First report of betalain production from endolichenic Bacillus sp. LDAB-1 from Dirinaria aegilita: Insights from novel quantification methodology of image processing.

Pigments are widely used in food supplements envisaging attractive colors along with health benefits. The desired advancements in the nutraceutical and antioxidant properties of pigments utilized in food products necessitate the search for novel additives. The present study is the first in the field to report the pigment-producing endolichenic bacteria, Bacillus sp. LDAB-1 from Dirinaria aegilita. Morphological, biochemical, and molecular characterization of the bacterium emphasizes that ideal pigment production occurs when utilizing sucrose and sodium nitrate. The pigment was salted out and dialyzed for further qualitative characterization using ultraviolet-visible, fluorescence, and Fourier transforminfraredspectra and the results corroborated the presence of betalains. The antioxidant activity of betalain is closer to the efficiency of α-tocopherol, which confers the pigment properties for antioxidant and nutraceutical significance. An optimal methodology for pigment affirmation is an issue when using an alternative methodology. Hence, the present assessment employs a comparative analysis of findings from both a spectrophotometric method and image processing technology encompassing RGB, CMYK, YCbCr, and L*a*b*color space models. Amongst these, the L*a*b* model potentially provides an effective modality for determining the pigment concentration. Bland-Altman plot analysis indicates similar consistency levels in betalain quantification by both methods at 95% confidence intervals, affirming the integrity and consistency of color image processing technology. Consequently, the present study represents novelty and innovativeness in reporting endolichenic Bacillus sp. LDAB-1 from D. aegilita and a rational image optimization protocol for pigment elucidation characteristics.

Debottlenecking the L-DOPA 4,5-dioxygenase step with enhanced tyrosine supply boosts betalain production in Nicotiana benthamiana.

Synthetic biology provides emerging tools to produce valuable compounds in plant hosts as sustainable chemical production platforms. However, little is known about how supply and utilization of precursors is coordinated at the interface of plant primary and specialized metabolism, limiting our ability to efficiently produce high levels of target specialized metabolites in plants. L-Tyrosine is an aromatic amino acid precursor of diverse plant natural products including betalain pigments, which are used as the major natural food red colorants and more recently a visual marker for plant transformation. Here, we studied the impact of enhanced L-tyrosine supply on the production of betalain pigments by expressing arogenate dehydrogenase (TyrA) from table beet (Beta vulgaris, BvTyrAα), which has relaxed feedback inhibition by L-tyrosine. Unexpectedly, betalain levels were reduced when BvTyrAα was coexpressed with the betalain pathway genes in Nicotiana benthamiana leaves; L-tyrosine and 3,4-dihydroxy-L-phenylalanine (L-DOPA) levels were drastically elevated but not efficiently converted to betalains. An additional expression of L-DOPA 4,5-dioxygenase (DODA), but not CYP76AD1 or cyclo-DOPA 5-O-glucosyltransferase, together with BvTyrAα and the betalain pathway, drastically enhanced betalain production, indicating that DODA is a major rate-limiting step of betalain biosynthesis in this system. Learning from this initial test and further debottlenecking the DODA step maximized betalain yield to an equivalent or higher level than that in table beet. Our data suggest that balancing between enhanced supply ("push") and effective utilization ("pull") of precursor by alleviating a bottleneck step is critical in successful plant synthetic biology to produce high levels of target compounds.

Are seven amino acid substitutions sufficient to explain the evolution of high l-DOPA 4,5-dioxygenase activity leading to betalain pigmentation? Revisiting the gain-of-function mutants of Bean et al. (2018).

This work revisits a publication by Bean etal. (2018) that reports seven amino acid substitutions are essential for the evolution of l-DOPA 4,5-dioxygenase (DODA) activity in Caryophyllales. In this study, we explore several concerns which led us to replicate the analyses of Bean etal. (2018). Our comparative analyses, with structural modelling, implicate numerous residues additional to those identified by Bean etal. (2018), with many of these additional residues occurring around the active site of BvDODAα1. We therefore replicated the analyses of Bean etal. (2018) to re-observe the effect of their original seven residue substitutions in a BvDODAα2 background, that is the BvDODAα2-mut3 variant. Multiple invivo assays, in both Saccharomyces cerevisiae and Nicotiana benthamiana, didnot result in visible DODA activity in BvDODAα2-mut3, with betalain production always 10-fold below BvDODAα1. In vitro assays also revealed substantial differences in both catalytic activity and pH optima between BvDODAα1, BvDODAα2 and BvDODAα2-mut3 proteins, explaining their differing performance invivo. In summary, we were unable to replicate the invivo analyses of Bean etal. (2018), and our quantitative invivo and invitro analyses suggest a minimal effect of these seven residues in altering catalytic activity of BvDODAα2. We conclude that the evolutionary pathway to high DODA activity is substantially more complex than implied by Bean etal. (2018).

Chemical composition and antioxidant properties of beetroot parasitized by Meloidogyne javanica and treated with elicitors

Beetroot is rich in nutrients and bioactive compounds, such as, betalains and phenolics. The objective of this work was to analyze the chemical composition and antioxidant properties of beetroot parasitized by Meloidogyne javanica and treated with elicitors. Beet seedlings were inoculated with 1000 eggs and second-stage juveniles of M. javanica and treated with elicitors based on mannan oligosaccharides, citrus biomass, or acibenzolar-S-methyl (ASM). At 60 days after inoculation, plants were evaluated for nematode reproduction factor (RF), proximate composition, betalains, phenolic compounds, and antioxidant activity. Beetroot was found to be susceptible to M. javanica, with RF values ranging from 15.26 to 27.94. ASM and citrus biomass treatments increased ash content by 15–25% in nematode-inoculated plants. There was no treatment effect on moisture or protein content, but uninoculated plants had higher total phenolic content (~35%) than inoculated plants. Nematode infection was found to compromise betalain production but did not impact antioxidant activity. Nematode-inoculated plants showed reduced sucrose content and increased glucose and fructose levels in all treatments. Regardless of the elicitor used, beetroots inoculated M. javanica exhibit deformities that render them unmarketable in fresh form. However, the results indicate that nematode-infected beetroot may be suitable for industrial processing and compound extraction.

Generating colorful carrot germplasm through metabolic engineering of betalains pigments.

Betalains are tyrosine-derived plant pigments exclusively found in the Caryophyllales order and some higher fungi and generally classified into two groups: red-violet betacyanins and yellow-orange betaxanthins. Betalains attract great scientific and economic interest because of their relatively simple biosynthesis pathway, attractive colors and health-promoting properties. Co-expressing two core genes BvCYP76AD1 and BvDODA1 with or without a glycosyltransferase gene MjcDOPA5GT allowed the engineering of carrot (an important taproot vegetable) to produce a palette of unique colors. The highest total betalains content, 943.2μg·g-1 DW, was obtained in carrot taproot transformed with p35S:RUBY which produces all of the necessary enzymes for betalains synthesis. Root-specific production of betalains slightly relieved tyrosine consumption revealing the possible bottleneck in betalains production. Furthermore, a unique volcano-like phenotype in carrot taproot cross-section was created by vascular cambium-specific production of betalains. The betalains-fortified carrot in this study is thus anticipated to be used as functional vegetable and colorful carrot germplasm in breeding to promote health.

Metabolic engineering of betacyanin in vegetables for anti-inflammatory therapy.

Betalains, which consist of the subgroups betaxanthins and betacyanins, are hydrophilic pigments that have classically been used for food colorants. Owing to their strong antioxidant property, their usefulness for application for therapeutic use is also expected. In addition, as betalains are mainly naturally available from plants of the order Caryophyllales, including beet (Beta vulgaris), metabolic engineering for betalain production in crops such as vegetables, fruits and cereals may provide new food resources useful for healthcare. Here we conducted metabolic engineering of betacyanins in tomato fruits and potato tubers. The transgenic tomato fruits and potato tubers with coexpression of betacyanin biosynthesis genes, CYP76AD1 from B. vulgaris, DOD (DOPA 4,5-dioxygenase) and 5GT (cyclo-DOPA 5-O-glucosyltransferase) from Mirabilis jalapa, under control of suitable specific promoters, possessed dark red tissues with enriched accumulation of betacyanins (betanin and isobetanin). The anti-inflammatory activity of transgenic tomato fruit extract was superior to that of wild-type fruit extract on macrophage RAW264.7 cells stimulated with lipopolysaccharide (LPS), as a result of decreased LPS-stimulated transcript levels of proinflammatory genes. These findings were in accord with the observation that administration of the transgenic tomato fruits ameliorated dextran sulfate sodium (DSS)-induced colitis as well as body weight loss and disease activity index in mice, via suppression of DSS-stimulated transcript levels of pro-inflammatory genes, including Tnf (encoding TNF-alpha), Il6, and Ptgs2 (encoding cyclooxygenae 2). Intriguingly, given the fact that the transgenic potato tuber extract failed to enrich the anti-inflammatory activity of macrophage cells, it is likely that metabolic engineering of betacyanins will be a powerful way of increasing the anti-inflammatory property of ordinary foods such as tomato.

Evaluation of Natural Pigments Production in Response to Various Stress Signals in Cell Lines of Stenocereus queretaroensis.

Stenocereus queretaroensis (F.A.C. Weber ex Mathes.) Buxb is a cactus that has long been used as a source food in central and northern México. Its fruits, commonly called pitayas, biosynthesize high amounts of betalains. These molecules are water-soluble nitrogenous compounds; that compared to other pigments, such as anthocyanins or carotenoids, stand out for their physicochemical stability in industrial processes. Due to genetic and environmental factors involved in the biosynthesis and accumulation of secondary metabolites in plants, we tested different stress-inducing agents (elicitor, osmotic, salt, and temperature) to induce betalains accumulation in cell culture from fruits of Stenocereus queretaroensis. This work aimed to understand stress conditions that induce the metabolic pathways required for the accumulation of betalains. The results show how betacyanin concentration increases under high sugar conditions, thus affecting the expression of L-DOPA 4, 5 dioxygenase resulting in a strong dark red coloration. This suggests this enzyme is part of a rate-limiting step in betalain production. In addition, we found that betalains accumulation occurs under particular stress conditions. Cells that have a high level of betacyanins show better resistance to stress in the cell culture, as well as an overall different behavior including cell aggregation and alterations in nuclear size. Together the results shown here may provide new strategies to manipulate and mass produce the pigments from Stenocereus queretaroensis in cell culture.

Benchmarking Intrinsic Promoters and Terminators for Plant Synthetic Biology Research.

The emerging plant synthetic metabolic engineering has been exhibiting great promise to produce either value-added metabolites or therapeutic proteins. However, promoters for plant pathway engineering are generally selected empirically. The quantitative characterization of plant-based promoters is essential for optimal control of gene expression in plant chassis. Here, we used N. benthamiana leaves and BY2 suspension cells to quantitatively characterize a library of plant promoters by transient expression of firefly/Renilla luciferase. We validated the dual-luciferase reporter system by examining the correlation between reporter protein and mRNA levels. In addition, we investigated the effects of terminator-promoter combinations on gene expression and found that the combinations of promoters and terminators resulted in a 326-fold difference between the strongest and weakest performance, as reflected in reporter gene expression. As a proof of concept, we used the quantitatively characterized promoters to engineer the betalain pathway in N. benthamiana. Seven selected plant promoters with different expression strengths were used orthogonally to express CYP76AD1 and DODA, resulting in a final betalain production range of 6.0-362.4 μg/g fresh weight. Our systematic approach not only demonstrates the various intensities of multiple promoter sequences in N. benthamiana and BY2 cells but also adds to the toolbox of plant promoters for plant engineering.

Effect of amino acid supplementation, elicitation and LEDs on Hylocereus costaricensis callus culture for the enhancement of betalain pigments

Hylocereus costaricensis more popularly known as the purplish-red pitaya or dragon fruit belongs to the Cactaceae family. The present study analyzes the effect of amino acids, elicitors, and light quality to improve callus proliferation, enhance betalain content and antioxidant profiles through elicitation and amino acid supplementation. The treatments that stimulated the highest total betalain content in red callus cultures were 50 µM tyrosine that produced a 1.6-fold increase (11.28 ± 0.38 mg/g DM) in betalain content and 200 µM leucine that produced 2.56-fold increase (18.13 ± 5.98 mg/g DM) in betalain content. Elicitation of yellow callus cultures with 100 mg/L yeast extract enhanced betalain content by 2-fold without affecting callus biomass. Betalain content could also be improved by 1.23-fold with 20 µM silver nitrate (12.51 ± 0.55 mg/g DM) while callus dry mass and total phenolic content were elevated at 40 µM silver nitrate. The utilization of light was a promising strategy for increased production of secondary metabolites in callus cultures of H. costaricensis. Both yellow and red callus cultures incubated under red LED lights enhanced total betalain content by 3.8- fold (11.64 ± 0.54 mg/g DM) and 4.8-fold (9.42 ± 1.48 mg/g DM), significantly higher (p < 0.01) than cool white LED lights (control treatment). Amino acid supplementation and elicitation strategies in this study achieved betalain content in yellow and red callus that was higher than that in dragon fruit peel (6.31 ± 1.82 mg/g DM), the pulp (3.26 ± 0.26 mg/g DM), and in vitro seedlings (2.01 ± 0.12 mg/g DM). The present investigation reports a simple and efficient protocol for in vitro betalain production from H. costaricensis. This study may enable the future commercial production of betalain compounds under a controlled environment, independent of climate and soil conditions.

Engineering Betalain Biosynthesis in Tomato for High Level Betanin Production in Fruits.

Betalains are pigments found in plants of the Caryophyllales order, and include the red-purple betacyanins and the yellow-orange betaxanthins. The red pigment from red beets, betanin, is made from tyrosine by a biosynthetic pathway that consists of a cytochrome P450, a L-DOPA dioxygenase, and a glucosyltransferase. The entire pathway was recently reconstituted in plants that do not make betalains naturally including potato and tomato plants. The amount of betanin produced in these plants was however not as high as in red beets. It was recently shown that a plastidic arogenate dehydrogenase gene involved in biosynthesis of tyrosine in plants is duplicated in Beta vulgaris and other betalain-producing plants, and that one of the two encoded enzymes, BvADHα, has relaxed feedback inhibition by tyrosine, contributing to the high amount of betanin found in red beets. We have reconstituted the complete betanin biosynthetic pathway in tomato plants with or without a BvADHα gene, and with all genes expressed under control of a fruit-specific promoter. The plants obtained with a construct containing BvADHα produced betanin at a higher level than plants obtained with a construct lacking this gene. These results show that use of BvADHα can be useful for high level production of betalains in heterologous hosts. Unlike red beets that produce both betacyanins and betaxanthins, the transformed tomatoes produced betacyanins only, conferring a bright purple-fuschia color to the tomato juice.

Virus-Mediated Transient Expression Techniques Enable Functional Genomics Studies and Modulations of Betalain Biosynthesis and Plant Height in Quinoa.

Quinoa (Chenopodium quinoa), native to the Andean region of South America, has been recognized as a potentially important crop in terms of global food and nutrition security since it can thrive in harsh environments and has an excellent nutritional profile. Even though challenges of analyzing the complex and heterogeneous allotetraploid genome of quinoa have recently been overcome, with the whole genome-sequencing of quinoa and the creation of genotyped inbred lines, the lack of technology to analyze gene function in planta is a major limiting factor in quinoa research. Here, we demonstrate that two virus-mediated transient expression techniques, virus-induced gene silencing (VIGS) and virus-mediated overexpression (VOX), can be used in quinoa. We show that apple latent spherical virus (ALSV) can induce gene silencing of quinoa phytoene desaturase (CqPDS1) in a broad range of quinoa inbred lines derived from the northern and southern highland and lowland sub-populations. In addition, we show that ALSV can be used as a VOX vector in roots. Our data also indicate that silencing a quinoa 3,4-dihydroxyphenylalanine 4,5-dioxygenase gene (CqDODA1) or a cytochrome P450 enzyme gene (CqCYP76AD1) inhibits betalain production and that knockdown of a reduced-height gene homolog (CqRHT1) causes an overgrowth phenotype in quinoa. Moreover, we show that ALSV can be transmitted to the progeny of quinoa plants. Thus, our findings enable functional genomics in quinoa, ushering in a new era of quinoa research.

Advances and future directions in betalain metabolic engineering.

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.

Scaled-up biotechnological production of individual betalains in a microbial system.

SummaryThe recent interest in plant pigment betalains as bioactive compounds and chemopreventive agents has led to the search for a reliable and scalable process to obtain them. The cloning of the novel and efficient enzyme 4,5‐DOPA‐extradiol dioxygenase from Gluconacetobacter diazotrophicus in an expression vector, and the subsequent heterologous expression in Escherichia coli cultures has led to the start‐up of a biotechnological production system of individual pigments. The aim of this study was to search for the optimal conditions for the production of betalamic acid in microbial factories and the scaled‐up obtention of the derived pigments. Four different betaxanthins and two betacyanins were obtained after the addition of non‐transformable amines and amino acids and their condensation with the betalamic acid produced by the dioxygenase. The scaled‐up obtention and purification of betalains improved the yields of the previous methodologies reaching quantities by up to 150 mg of pure compounds.

Preharvest application of ethephon and postharvest UV-B radiation improve quality traits of beetroot (Beta vulgaris L. ssp. vulgaris) as source of colourant

BackgroundBetanins have become excellent replacers for artificial red-purple food colourants. Red beet (Beta vulgaris L. spp. vulgaris) known as beetroot, is a rich source of betalains, which major forms are betanin (red to purple) and vulgaxanthin (yellow). Betalains and phenolic compounds are secondary metabolites, accumulation of which is often triggered by elicitors during plant stress responses. In the present study, pre-harvest applications of ethephon (an ethylene-releasing compound) and postharvest UV-B radiation were tested as elicitors of betalains and phenolic compounds in two beetroot cultivars. Their effects on quality parameters were investigated, and the expression of biosynthetic betalain genes in response to ethephon was determined.ResultsEthephon was applied as foliar spray during the growth of beetroot, resulting in increased betanin (22.5%) and decreased soluble solids contents (9.4%), without detrimental effects on beetroot yield. The most rapid accumulation rate for betanin and soluble solids was observed between 3 and 6 weeks after sowing in both untreated and ethephon-treated beetroots. Overall, the expression of the betalain biosynthetic genes (CYP76AD1, CYP76AD5, CYP76AD6 and DODA1), determining the formation of both betanin and vulgaxanthin, increased in response to ethephon treatment, as did the expression of the betalain pathway activator BvMYB1. In the postharvest environment, the use of short-term UV-B radiation (1.23 kJ m− 2) followed by storages for 3 and 7 days at 15 °C resulted in increased betanin to vulgaxanthin ratio (51%) and phenolic content (15%).ConclusionsThe results of this study provide novel strategies to improve key profitability traits in betalain production. High betanin concentration and high betanin to vulgaxanthin ratio increase the commercial value of the colourant product. In addition, lowering soluble solids levels facilitates higher concentration of beetroot colour during processing. Moreover, we show that enhanced betanin content in ethephon-treated beetroots is linked to increased expression of betalain biosynthetic genes.

UV-B radiation as an elicitor of secondary metabolite production in plants of the genus Alternanthera

Ultraviolet B radiation has been described as a potential elicitor agent of the synthesis of secondary metabolites in plants. Thus, the present study aimed to investigate the production of betalains and total flavonoids, as well as the antioxidant activity, of Alternanthera sessilis, A. brasiliana, A. tenella and A. philoxeroides exposed to different periods of UV-B radiation (280-315 nm). Plants of these four species were exposed to UV-B radiation for 0, 2, 4, 6, and 8 hours, which amounts to 0, 10, 20, 30, and 40 J cm−2 of radiation, respectively. Significant increases in betacyanin and betaxanthin levels were observed in A. sessilis and A. brasiliana during the period of UV-B exposure, while no differences were observed for the others species. The highest estimated flavonoid levels were for A. sessilis exposed to UV-B radiation for 8 h, followed by a 24-h recovery period. In conclusion, the action of UV-B radiation as an inducer of defence responses in plants is influenced by increasing exposure periods followed by a recovery period. Both increase the levels of these composts, yet this increase is different among the four Alternanthera species, having a greater influence on the species A. sessilis and A. brasiliana.

English

Alternanthera brasiliana is a medicinal plant with several popular use and high production of betalains. The aim of the present research was to establish a protocol for callus induction and betalain biosynthesis in A. brasiliana species, as well as to investigate the effect of different qualities of light in increasing betalain in A. brasiliana callus cultures. In this way, the callus initiation and the improvement of secondary metabolites were induced using varying phytohormones concentrations and under the influence of red, white and blue lights. To start the experiments, the plants were cultivated for 30 days in Murashige and Skoog (MS) medium to grow and form internodes. These were inoculated in MS medium supplemented with different combinations of plant growth regulators to find the best combination for medium callus induction (MCI). After another 30 days, the explants were transferred to a medium for betacyanin induction (MBI) containing thidiazuron (TDZ) and α-naphthalene acetic acid (NAA) under blue, white, and red lights. The best medium for A. brasiliana callus induction with higher production of betalains, was the MS medium supplemented white indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D), before inoculation on the MBI. The blue and white lights promoted callus pigmentation (betalains), whereas the red light was not effective at inducing pigmentation in the calli. Key words: Amaranthaceae, betacyanin, betalains, pigments, spectra of light, secondary metabolites

Stable transformation of Opuntia ficus indica callus cultures as evidenced by fluorescence of the tandem dimer Tomato gene

This communication provides a protocol for stable transformation of Opuntia callus cultures. Itis a summary of ten years research from 2006 to 2016 of more than 340 experiments toobtain stable transformation and regeneration of five clones of Opuntia ficus-indica. Althoughregeneration was not achieved, stable transformation was achieved as evidenced byexpression of a fluorescent marker gene six months after inoculation by soaking explantsderived from unopened floral buds in Agrobacterium tumefaciens EHA 101. As cactus hadtoo much auto fluorescence to permit use of even enhanced green fluorescent proteins, thefluorescent marker TdTomato with red/orange emission was used. To avoid consumerobjections from antibiotic selective marker systems, the Phosphomannose Isomerase (PMI)gene that screens for growth on mannose was used. Explants that fluoresced grew well up to10 g L-1 mannose, while explants that did not fluoresce senesced and died when cultured on2 g L-1 mannose. The optimal basal media were found to be either Murashige-Skoog with 30g L-1 sucrose, with either double the standard Ca concentration or Woody Plant media with anadditional 2,000 mg L-1 KNO3. Standard liquid shake, temporary immersion system or solidagar with 3 g L-1 gel rite was examined and the solid gel rite media was used. Previousreports that reported stable transformation of meristems by needle injection could not berepeated, possibly because those experiments were conducted with non-intron GUS thatwould have permitted the Agrobacterium to properly transcribe and splice transcripts for theuidA gene. Two independent reports of somatic embryogenesis Bouamama et al. (2011) andGomez et al. (2006) in Opuntia were intensively examined, but could not be repeated.However smooth, green structures similar to “nodules” described by McGown et al. (1988)that can be induced to produce shoots were obtained but could not be induced to produceshoots. The hormone combinations that resulted in the greatest “structure” from immaturefloral explants were Zeatin (ZA) 0.2 to 0.75 mg L-1 with naphthalene acetic acid (NAA) 0.2 mg&#x0D; L-1, or Thidiazuron (TDZ) 0.75 with ZA 0.5 and NAA 0.4 mg L-1, or metatopolin 1.5 with NAA0.25 mg L-1. Long-term culture on Picloram (PIC) resulted in cultures with a red tinge,thought to be stress-induced betalain production. However, the most promising hormonecombination with (PIC) on floral explants was 0.01 TDZ/0.06 ZA/0.02 mg L-1 PIC. It issuggested that the most promising approaches to obtain shoots from these types ofstructures will come from transient or stable expression of the WUSCHEL and/orBABYBOOM regulatory genes in order to stimulate shoot development.

Feasibility and transcriptomic analysis of betalain production by biomembrane surface fermentation of Penicillium novae-zelandiae

In this study, a biomembrane surface fermentation was used to produce red pigments of Penicillium novae-zelandiae, and the significant improvement in pigment production by the addition of 0.4 g/L of tyrosine demonstrated that the red pigments probably contained betalain. Therefore, one red pigment was purified, and identified as 2-decarboxybetanin by high-resolution mass spectrometry (MS) and MS/MS analysis. Transcriptomic analysis revealed the differentially expressed genes and metabolic profile of P. novae-zelandiae in response to different cultivations and exhibited the complete biosynthetic pathway of 2-decarboxybetanin in P. novae-zelandiae. Betalains are important water-soluble nitrogen-containing food coloring agents, obtained mainly from beetroot by chemical extraction. This paper is the first report about the production of betalain by microbial fermentation, and results exhibit the possible use of fungal fermentation in future 2-decarboxybetanin production.