Increase In Β-carotene Content Research Articles

Hexanoic acid addition helps to clarify the possible mechanisms of the increased β-carotene content during alfalfa fermentation

Hexanoic acid addition helps to clarify the possible mechanisms of the increased β-carotene content during alfalfa fermentation

Application of CRISPR/Cas-based gene-editing for developing better banana.

Banana (Musa spp.), including plantain, is one of the major staple food and cash crops grown in over 140 countries in the subtropics and tropics, with around 153 million tons annual global production, feeding about 400 million people. Despite its widespread cultivation and adaptability to diverse environments, banana production faces significant challenges from pathogens and pests that often coexist within agricultural landscapes. Recent advancements in CRISPR/Cas-based gene editing offer transformative solutions to enhance banana resilience and productivity. Researchers at IITA, Kenya, have successfully employed gene editing to confer resistance to diseases such as banana Xanthomonas wilt (BXW) by targeting susceptibility genes and banana streak virus (BSV) by disrupting viral sequences. Other breakthroughs include the development of semi-dwarf plants, and increased β-carotene content. Additionally, non-browning banana have been developed to reduce food waste, with regulatory approval in the Philippines. The future prospects of gene editing in banana looks promising with CRISPR-based gene activation (CRISPRa) and inhibition (CRISPRi) techniques offering potential for improved disease resistance. The Cas-CLOVER system provides a precise alternative to CRISPR/Cas9, demonstrating success in generating gene-edited banana mutants. Integration of precision genetics with traditional breeding, and adopting transgene-free editing strategies, will be pivotal in harnessing the full potential of gene-edited banana. The future of crop gene editing holds exciting prospects for producing banana that thrives across diverse agroecological zones and offers superior nutritional value, ultimately benefiting farmers and consumers. This article highlights the pivotal role of CRISPR/Cas technology in advancing banana resilience, yield and nutritional quality, with significant implications for global food security.

Enhancement of β-carotene content in Chlamydomonas reinhardtii by expressing bacterium-driven lycopene β-cyclase

β-Carotene is one of the economically important carotenoids, having functions as the antioxidant to remove harmful free radicals and as the precursor for vitamin A and other high-valued xanthophyll such as zeaxanthin and astaxanthin. Lycopene cyclase plays an important role in the branching of β-carotene and α-carotene. Aiming to develop the microalgae with enhanced β-carotene productivity, the CrtY gene from bacterium Pantoea agglomerans was integrated into Chlamydomonas reinhardtii. The lycopene-producing E. coli harboring CrtY gene produced 1.59 times of β-carotene than that harboring DsLcyb1 from Dunaliella salina (a microalga with abundant β-carotene), confirming the superior activity of CrtY on β-carotene biosynthesis. According to the pigment analysis by HPLC, in microalgal transformants that were confirmed by molecular analysis, the expression of CrtY significantly increased β-carotene content from 12.48 mg/g to 30.65 mg/g (dry weight), which is about 2.45-fold changes. It is noted that three out of five transformants have statistically significant higher amount of lutein, even though the increment was 20% in maximum. Besides, no growth defect was observed in the transformants. This is the first report of functional expression of prokaryotic gene in eukaryotic microalgae, which will widen the gene pool targeting carotenoids biosynthesis using microalgae as the factory and thereby provide more opportunity for high-valued products engineering in microalgae.

AgMYB5, an MYB transcription factor from celery, enhanced β-carotene synthesis and promoted drought tolerance in transgenic Arabidopsis

BackgroundWater shortage caused by global warming seriously affects the yield and quality of vegetable crops. β-carotene, the lipid-soluble natural product with important pharmacological value, is abundant in celery. Transcription factor MYB family extensively disperses in plants and plays regulatory roles in carotenoid metabolism and water scarcity response.ResultsHere, the AgMYB5 gene encoding 196 amino acids was amplified from celery cv. ‘Jinnanshiqin’. In celery, the expression of AgMYB5 exhibited transactivation activity, tissue specificity, and drought-condition responsiveness. Further analysis proved that ectopic expression of AgMYB5 increased β-carotene content and promoted drought tolerance in transgenic Arabidopsis thaliana. Moreover, AgMYB5 expression promoted β-carotene biosynthesis by triggering the expression of AtCRTISO and AtLCYB, which in turn increased antioxidant enzyme activities, and led to the decreased contents of H2O2 and MDA, and the inhibition of O2− generation. Meanwhile, β-carotene accumulation promoted endogenous ABA biosynthesis of transgenic Arabidopsis, which resulted in ABA-induced stomatal closing and delayed water loss. In addition, ectopic expression of AgMYB5 increased expression levels of AtERD1, AtP5CS1, AtRD22, and AtRD29.ConclusionsThe findings indicated that AgMYB5 up-regulated β-carotene biosynthesis and drought tolerance of Arabidopsis.

β-carotene genetically-enriched lyophilized orange juice increases antioxidant capacity and reduces β-amyloid proteotoxicity and fat accumulation in Caenorhabditis elegans

Citrus sinensis orange juice is an excellent dietary source of β-carotene, a well-known antioxidant. However, β-carotene concentrations are relatively low in most cultivars. We developed a new orange through metabolic engineering strategy (GS) with 33.72-fold increase in β-carotene content compared to its conventional counterpart (CV). Using Caenorhabditis elegans, we found that animals treated with GS showed a greater reduction in intracellular reactive oxygen species (ROS) which is associated with a greater resistance to oxidative stress and induction of the expression of antioxidant genes. Moreover, animals treated with GS orange showed a more effective protection against β-amyloid proteotoxicity and greater hypolipidemic effect under high glucose diet compared to animals treated with CV. These data demonstrate that the increased amount of β-carotene in orange actually provides a greater beneficial effect in C. elegans and a valuable proof of principle to support further studies in mammals and humans.

Quality Attributes of Pupuru Analogue Produced from Orange Fleshed Sweet Potato (OFSP) as Influenced by Fermentation with Rhizopus oligosporous

In this work, orange fleshed sweet potato (OFSP), rich in β-carotene and other micronutrients was used in producing pupuru analogue with the aim of improving the micronutrient and other quality attributes of the product. an analogue of pupuru normally a cassava-based food was developed from Orange Fleshed Sweet Potato (OFSP). The OFSP tubers were peeled, washed, grated and fermented with Rhizopus oligosporous for varying periods (0, 24, 48, 72, 96, 120 h). After fermentation period, each sample was subsequently smoke-dried and milled into pupuru analogue flour. The flour was analysed for proximate, physicochemical, minerals, vitamins and anti-nutritional factors. Sensory evaluation was carried out on the pupuru meals prepared from the flour samples by reconstituting in boiling water. The protein content ranged from 3.4 to 5.41% with increased in fermentation period. Similarly, there was increase in β-carotene content from 117-126 mg/100g after 120 h fermentation period. Vitamins B6 and C ranged from 1.73 to 3.20 mg100g and 12 .3 to 21.1 mg/100g respectively. Oxalate, tannin and phytate decreased from 123.0 to 72.5 mg/100g, 1.10 to 1.05mg/100g and 1.62 to 1.16mg/100g respectively. Sensory scores showed that pupuru analogue fermented for 96 and 120 h were preferred most in terms of overall acceptability.

Simultaneous accumulation of astaxanthin and β-carotene in Chlamydomonas reinhardtii by the introduction of foreign β-carotene hydroxylase gene in response to high light stress.

Carotenoids are important photosynthetic pigments with many physiological functions, nutritional properties and high commercial value. β-carotene hydroxylase is one of the key enzymes in the carotenoid synthesis pathway of Chlamydomonas reinhardtii for the conversion of β-carotene to astaxanthin. The vector p64DZ containing the β-carotene hydroxylase gene crtZ from Haematococcus pluvialis was transformed into C. reinhardtii CC-503. The transformants were selected by alternate culture in solid-liquid medium containing spectinomycin (100µgmL-1). PCR results indicated that the gene crtZ and aadA were integrated into the genome of C. reinhardtii. RT-PCR analysis showed that the gene crtZ was transcribed in Chlamydomonas transformants. HPLC analysis showed that the content of astaxanthin and β-carotene in cells of C. reinhardtii were simultaneously increased. Under medium light intensity cultivation (60µmolm-2s-1), transgenic C. reinhardtii had an 85.8% increase in β-carotene content compared with the wild type. The content of astaxanthin and β-carotene reached 1.97 ± 0.13mgg-1 fresh cell weight (FCW) and 105.94 ± 5.84µgg-1 FCW, which were increased 18% and 42.4% than the wild type after 6h of high light treatment (200µmolm-2s-1), respectively. Our results indicate the regulatory effect on pigments in C. reinhardtii by β-carotene hydroxylase gene of H. pluvialis, and demonstrate the positive effect of high light stress on pigment accumulation in transgenic C. reinhardtii.

Characterization and functional validation of β-carotene hydroxylase AcBCH genes in Actinidia chinensis.

Carotenoids are the pigment substances of yellow-fleshed kiwifruit, and among them β-cryptoxanthin has only been detected in the brighter yellow-fleshed variety ‘Jinshi 1’. β-Carotene hydroxylase (BCH) catalyzes the formation of β-cryptoxanthin and zeaxanthin, but its molecular characteristics and functions have not been fully explained. Here we isolated two β-carotene hydroxylase genes, AcBCH1 and AcBCH2 from kiwifruit (Actinidia chinensis), and their relative expression levels exhibited a close correlation with the content of β-cryptoxanthin. AcBCH1 catalyzed the formation of β-cryptoxanthin when transformed into β-carotene-accumulating yeast cells. Moreover, silenced expression of AcBCH1 in kiwifruit caused decreases in the contents of zeaxanthin, lutein, and β-cryptoxanthin, and an increase in β-carotene content. The content of β-carotene decreased significantly after the AcBCH1/2 genes were overexpressed in tomato. The content of zeaxanthin increased and β-carotene decreased in transgenic kiwifruit seedlings. The results will enrich our knowledge of the molecular mechanisms of carotenoid biosynthesis in kiwifruit.

Dual regulation of lipid droplet-triacylglycerol metabolism and ERG9 expression for improved \u03b2-carotene production in Saccharomyces cerevisiae

BackgroundThe limitation of storage space, product cytotoxicity and the competition for precursor are the major challenges for efficiently overproducing carotenoid in engineered non-carotenogenic microorganisms. In this work, to improve β-carotene accumulation in Saccharomyces cerevisiae, a strategy that simultaneous increases cell storage capability and strengthens metabolic flux to carotenoid pathway was developed using exogenous oleic acid (OA) combined with metabolic engineering approaches.ResultsThe direct separation of lipid droplets (LDs), quantitative analysis and genes disruption trial indicated that LDs are major storage locations of β-carotene in S. cerevisiae. However, due to the competition for precursor between β-carotene and LDs-triacylglycerol biosynthesis, enlarging storage space by engineering LDs related genes has minor promotion on β-carotene accumulation. Adding 2 mM OA significantly improved LDs-triacylglycerol metabolism and resulted in 36.4% increase in β-carotene content. The transcriptome analysis was adopted to mine OA-repressible promoters and IZH1 promoter was used to replace native ERG9 promoter to dynamically down-regulate ERG9 expression, which diverted the metabolic flux to β-carotene pathway and achieved additional 31.7% increase in β-carotene content without adversely affecting cell growth. By inducing an extra constitutive β-carotene synthesis pathway for further conversion precursor farnesol to β-carotene, the final strain produced 11.4 mg/g DCW and 142 mg/L of β-carotene, which is 107.3% and 49.5% increase respectively over the parent strain.ConclusionsThis strategy can be applied in the overproduction of other heterogeneous FPP-derived hydrophobic compounds with similar synthesis and storage mechanisms in S. cerevisiae.Graphical

Changes in Compositional Properties during Fruit Development and On-Tree Ripening of Two Common Apricot (Prunus armeniaca L.) Cultivars.

The objective of the present study was to investigate the variations in some major primary (sugars and organic acids) and secondary (phenolics, β-carotene) metabolite contents during fruit development and ripening in two important apricot cultivars (Hacıhaliloğlu and Kabaaşı). The changes in the compositional properties of two apricot cultivars were monitored during fruit development with one-week intervals from 56 to 119 days after blossom. During fruit development, the contents of organic acids and phenolics decreased whereas that of sucrose and sorbitol increased. p-Coumaric acid was the only phenolic compound which increased in concentration during fruit development regardless of the cultivar. The content of the other phenolic compounds decreased in a cultivar-dependent manner. The β-carotene content of the cultivars showed distinct patterns of change such that 3 fold increase in β-carotene content of Kabaaşı cultivar was observed whereas the β-carotene content of the Hacıhaliloğlu cultivar did not show any significant change during fruit development.

Nutrient Concentration of African Horned Cucumber (Cucumis metuliferus L) Fruit under Different Soil Types, Environments, and Varying Irrigation Water Levels

The nutrient concentration of most crops depends on factors such as amount of water, growing environment, sunlight, and soil types. However, the factors influencing nutrient concentration of African horned cucumber fruit are not yet known. The objective of the study was to determine the effect of different water stress levels, soil types, and growing environments on the nutrient concentration of African horned cucumber fruit. Freeze-dried fruit samples were used in the quantification of β-carotene and total soluble sugars. The results demonstrated that plants grown under the shade net, combined with severe water stress level and loamy soil, had increased total soluble sugars (from 8 to 16 °Brix). Under the shade-net environment, the combination of moderate water stress level and loamy soil resulted in increased crude protein content (from 6.22 to 6.34% °Brix). In addition, the severe water stress treatment combined with loamy soil, under greenhouse conditions, resulted in increased β-carotene content (from 1.5 to 1.7 mg 100 g−1 DW). The results showed that African horned cucumber fruits are nutrient-dense when grown under moderate water stress treatment on the loamy or sandy loam substrate in the shade-net and open-field environments.

Molybdenum disulfide nanoparticles concurrently stimulated biomass and β-carotene accumulation in Dunaliella salina

Molybdenum disulfide nanoparticles (MoS2 NPs) hold tremendous properties in wide domain of applications. In this study, the impact of MoS2 NPs was investigated on algal physiological and metabolic properties and a two-stage strategy was acquired to enhance the commercial potential of Dunaliella salina. With 50 µg/L of MoS2 NPs exposure, cellular growth and biomass production were promoted by 1.47- and 1.33-fold than that in control, respectively. MoS2 NPs treated cells were subject to high light intensity for 7 days after 30 days of normal light cultivation, which showed that high light intensity gradually increased β-carotene content by 1.48-fold. Furthermore, analyses of primary metabolites showed that combinatorial approach significantly altered the biochemical composition of D. salina. Together, these findings demonstrated that MoS2 NPs at an optimum concentration combined with high light intensity could be a promising approach to concurrently enhance biomass and β-carotene production in microalgae.

Light dependent accumulation of β-carotene enhances photo-acclimation of Euglena gracilis

Carotenoids are essential components of photosynthetic organisms including land plants, algae, cyanobacteria, and photosynthetic bacteria. Although the light-mediated regulation of carotenoid biosynthesis, including the light/dark cycle as well as the dependence of carotenoid biosynthesis–related gene translation on light wavelength, has been investigated in land plants, these aspects have not been studied in microalgae. Here, we investigated carotenoid biosynthesis in Euglena gracilis and found that zeaxanthin accumulates in the dark. The major carotenoid species in E. gracilis, namely β-carotene, neoxanthin, diadinoxanthin and diatoxanthin, accumulated corresponding to the duration of light irradiation under the light/dark cycle, although the translation of carotenoid biosynthesis genes hardly changed. Irradiation with either blue or red-light (3 μmol photons m−2 s−1) caused a 1.3-fold increase in β-carotene content compared with the dark control. Blue-light irradiation (300 μmol photons m−2 s−1) caused an increase in the cellular content of both zeaxanthin and all trans-diatoxanthin, and this increase was proportional to blue-light intensity. In addition, pre-irradiation with blue-light of 3 or 30 μmol photons m−2 s−1 enhanced the photosynthetic activity and tolerance to high-light stress. These findings suggest that the accumulation of β-carotene is regulated by the intensity of light, which may contribute to the acclimation of E. gracilis to the light environment in day night conditions.

Manipulation of β-carotene levels in tomato fruits results in increased ABA content and extended shelf life.

SummaryTomato fruit ripening is controlled by the hormone ethylene and by a group of transcription factors, acting upstream of ethylene. During ripening, the linear carotene lycopene accumulates at the expense of cyclic carotenoids. Fruit‐specific overexpression of LYCOPENE β‐CYCLASE (LCYb) resulted in increased β‐carotene (provitamin A) content. Unexpectedly, LCYb‐overexpressing fruits also exhibited a diverse array of ripening phenotypes, including delayed softening and extended shelf life. These phenotypes were accompanied, at the biochemical level, by an increase in abscisic acid (ABA) content, decreased ethylene production, increased density of cell wall material containing linear pectins with a low degree of methylation, and a thicker cuticle with a higher content of cutin monomers and triterpenoids. The levels of several primary metabolites and phenylpropanoid compounds were also altered in the transgenic fruits, which could be attributed to delayed fruit ripening and/or to ABA. Network correlation analysis and pharmacological experiments with the ABA biosynthesis inhibitor, abamine, indicated that altered ABA levels were a direct effect of the increased β‐carotene content and were in turn responsible for the extended shelf life phenotype. Thus, manipulation of β‐carotene levels results in an improvement not only of the nutritional value of tomato fruits, but also of their shelf life.

The Increase in β-carotene Content in Dunaliella salina from the Application of Different Light Intensities

Dunaliella salina is an example of a natural source of β-carotene and it is made up of larger cells than others in the genus Dunaliella. It is therefore able to produce more β- carotene. Dunaliella salina is able to accumulate more β-carotene content when cultured in environmental stress conditions such as high salinity, low nutrients and high light. This study aims to determine the increase in β-carotene content in D. salina due to the application of difference light intensities and to further determine the maximal light intensity required to obtain the highest β-carotene content in D. salina. The treatments used were different light intensities of700 Lux, 2.200 Lux, 3.700 Lux and 5.200 Lux with five repetitions respectively. The primary parameter that was measured was the β-carotene content of D. salina. The supporting factors in this research were the growth of D. salina and the water quality; i.e. temperature, pH, and salinity. The results showed that different light intensities can increase the β-carotene content in D. salina with the increased light intensity being the treatment. The maximum light intensity required to produce the highest amount of β-carotene content was 5.200 Lux with 0,0087 ml/L. Based on these results, further research is needed regarding light intensities to see if it can tolerate further stimulated growth in order to produce β-carotene more.

Pigmented maize - a potential source of β-carotene and α-tocopherol

<p>Among cereals, maize has the highest content of bioavailable micronutrients in grain, particularly β-carotene and α-tocopherol, which makes this crop the most appropriate for biofortification. Great genetic variability is a valuable source of micronutrients, and genotypes with enhanced grain content could be used for improvement of commercial hybrids or synthetic populations creation. Three populations with dark orange, dark red and red grain, five elite lines, and their crosses were evaluated for β-carotene and α-tocopherol content. Based on obtained results, line (L5) could be further used in breeding for increased β-carotene content, and population with dark orange grain (P1) is recommended as a good source for multi-nutrient biofortification for both β-carotene and α-tocopherol. Three lines (L1, L2 and L5) had significantly higher value of α-tocopherol in crosses with dark red population (P2), compared to lines per se, and require several cycles of back-crossing for increase nutrient content.</p>

데치기(Blanching)로 조리된 22가지 채소류의 베타카로틴 함량의 변화와 영양소 보존율(True Retention)

In the present study, reversed-phase HPLC was utilized to quantify the β-carotene content of 22 kinds of raw and blanched vegetables consumed in Korea. In addition, true retention (TR) of β-carotene in samples was obtained. For quantification of β-carotene, external standard curve was obtained with limit of detection and limit of quantitation. The β-carotene contents in 22 raw vegetables ranged from 6.29 (bellflower root) to 7,050.73 μg/100 g (spinach, field culture). After blanching, β-carotene contents of 13 vegetables increased up to 103.05% while nine vegetables resulted in reduced content, ranging from -2.17 to -29.16%. However, even though increased β-carotene content was observed after blanching, TR of some vegetables was lower than 100% due to their weight reduction. The highest TR of β-carotene was found from blanched cabbage (164.46%) while the lowest TR was found from Turcz (Gomchwi) at 59.35%. TR is an effective method to evaluate retention of nutrients in cooked foods, considering changes of nutrient content and weight.

A new regulatory mechanism controlling carotenogenesis in the fungus Mucor circinelloides as a target to generate β-carotene over-producing strains by genetic engineering.

BackgroundCarotenoids are natural pigments with antioxidant properties that have important functions in human physiology and must be supplied through the diet. They also have important industrial applications as food colourants, animal feed additives and nutraceuticals. Some of them, such as β-carotene, are produced on an industrial scale with the use of microorganisms, including fungi. The mucoral Blakeslea trispora is used by the industry to produce β-carotene, although optimisation of production by molecular genetic engineering is unfeasible. However, the phylogenetically closely related Mucor circinelloides, which is also able to accumulate β-carotene, possesses a vast collection of genetic tools with which to manipulate its genome.ResultsThis work combines classical forward and modern reverse genetic techniques to deepen the regulation of carotenoid synthesis and generate candidate strains for biotechnological production of β-carotene. Mutagenesis followed by screening for mutants with altered colour in the dark and/or in light led to the isolation of 26 mutants that, together with eight previously isolated mutants, have been analysed in this work. Although most of the mutants harboured mutations in known structural and regulatory carotenogenic genes, eight of them lacked mutations in those genes. Whole-genome sequencing of six of these strains revealed the presence of many mutations throughout their genomes, which makes identification of the mutation that produced the phenotype difficult. However, deletion of the crgA gene, a well-known repressor of carotenoid biosynthesis in M. circinelloides, in two mutants (MU206 and MU218) with high levels of β-carotene resulted in a further increase in β-carotene content to differing extents with respect to the crgA single-null strain; in particular, one strain derived from MU218 was able to accumulate up to 4 mg/g of β-carotene. The additive effect of crgA deletion and the mutations present in MU218 suggests the existence of a previously unknown regulatory mechanism that represses carotenoid biosynthesis independently and in parallel to crgA.ConclusionsThe use of a mucoral model such as M. circinelloides can allow the identification of the regulatory mechanisms that control carotenoid biosynthesis, which can then be manipulated to generate tailored strains of biotechnological interest. Mutants in the repressor crgA and in the newly identified regulatory mechanism generated in this work accumulate high levels of β-carotene and are candidates for further improvements in biotechnological β-carotene production.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0493-8) contains supplementary material, which is available to authorized users.

Maize inbreds from different heterotic groups as favorable sources for increased potential bioavailability of magnesium, iron, manganese and zinc

Malnutrition, as a global problem, is mainly caused by low level of mineral elements in staple food (deficient soil). Biofortification is based on selection of genotypes with enhanced concentration of mineral elements in grain, as well as decreased concentration of substances which interfere bioavailability of mineral elements in gut (like phytic acid), and increased content of substances that increase availability (such as β-carotene). The experiment with 51 maize (Zea mays L.) inbred lines with different heterotic background was set up in order to evaluate chemical composition of grain and to determine the relations between phytic acid (PA), β-carotene, and mineral elements: Mg, Fe, Mn, and Zn. The highest average phytate, β-carotene, Fe, and Mn content was found in grain of inbreds from Lancaster heterotic group. The highest content of Mg was in grain of Independent source and Zn in grain of BSSS group. Increased level of Fe and Mn in Lancaster lines could be partially affected by higher PA content in grain, while increased β-carotene content could improve Mn and Zn availability from grain of BSSS genotypes and Mg availability from Lancaster inbreds. It is important to underline that PA reduction is followed by Zn content increase in grain of Lancaster heterotic group, as well as that variations in Mg, Fe, and Mn contents are independent on PA status in inbreds from Independent source, indicating that the genotypes with higher Mg, Fe and Mn status from this group could serve as favorable source for improved Mg, Fe, and Mn absorption.

Over-expression of StLCYb increases β-carotene accumulation in potato tubers

Lycopene b-cyclase (LCYb) is involved in the first step of the β-branch synthetic pathway of carotenoids from lycopene in plants. In this study, to explore the possibility of regulating β-carotene synthesis via the β-branch-specific pathway in potato, StLCYb gene was first isolated from potato cultivar Desiree, and its open reading frame was 1503 bp long without intron. The protein sequence of StLCYb showed high similarity with that of LCYbs in other species such as SlLCYb1, CaLCYb, NtLCYb and ApLCYb. StLCYb was expressed in all tissues and the highest level was observed in tubers followed in flowers, and the lowest level was in roots. HPLC detected an about 1.5–1.9 times increase in β-carotene content of transgenic potato tubers, in which the gene StLCYb was overexpressed, compared with the wild-type control. Besides, the expression levels of carotenoid-related genes StPSY, StPDS, StZDS, StCHYb and StZEP transcripts in the transgenic lines were significantly higher than in the wild-type control, which implied a positive regulation in promoting carotenoid synthesis. All these results suggest that β-carotene content in potato tubers could be regulated by modulating StLCYb expression.