Flesh Pigmentation Research Articles

StMYB44 negatively regulates anthocyanin biosynthesis at high temperatures in tuber flesh of potato.

High temperatures are known to reduce anthocyanin accumulation in a number of diverse plant species. In potato (Solanum tuberosum L.), high temperature significantly reduces tuber anthocyanin pigment content. However, the mechanism of anthocyanin biosynthesis in potato tuber under heat stress remains unknown. Here we show that high temperature causes reduction of anthocyanin biosynthesis in both potato tuber skin and flesh, with white areas forming between the vasculature and periderm. Heat stress reduced the expression of the R2R3 MYB transcription factors (TFs) StAN1 and StbHLH1, members of the transcriptional complex responsible for coordinated regulation of the skin and flesh pigmentation, as well as anthocyanin biosynthetic pathway genes in white regions. However, the core phenylpropanoid pathway, lignin, and chlorogenic acid (CGA) pathway genes were up-regulated in white areas, suggesting that suppression of the anthocyanin branch may result in re-routing phenylpropanoid flux into the CGA or lignin biosynthesis branches. Two R2R3 MYB TFs, StMYB44-1 and StMYB44-2, were highly expressed in white regions under high temperature. In transient assays, StMYB44 represses anthocyanin accumulation in leaves of Nicotiana tabacum and N. benthamiana by directly suppressing the activity of the dihydroflavonol reductase (DFR) promoter. StMYB44-1 showed stronger repressive capacity than StMYB44-2, with both predicted proteins containing the repression-associated EAR motif with some variation. StMYB44-1 conferred repression without a requirement for a basic helix-loop-helix (bHLH) partner, suggesting a different repression mechanism from that of reported anthocyanin repressors. We propose that temperature-induced reduction of anthocyanin accumulation in potato flesh is caused by down-regulation of the activating anthocyanin regulatory complex, by enhancing the expression of flesh-specific StMYB44 and alteration of phenylpropanoid flux.

Upregulation of MdMYB110a is responsible for ABA-mediated colouration of type 2 red-fleshed apples

ABSTRACTType 2 red-fleshed apples are attractive to consumers due to their sweet taste, which is not present in type 1 apples, in addition to their vivid colour and the accumulation of health-promoting polyphenol compounds to a greater degree than in white apples. Although the red pigmentation of type 2 apples is caused by the expression of MdMYB110a at colouring initiation, the endogenous factors that induce the expression of MdMYB110a are poorly understood. In this study, we investigated the effect of two phytohormones, ethylene and abscisic acid (ABA), on MdMYB110a expression and flesh pigmentation in type 2 red-fleshed apples. Although induction of the expression of the ethylene biosynthetic gene MdACO1 coincided with the onset of flesh pigmentation, no obvious correlation was found between treatment with ethylene or its inhibitor 1-methylcyclopropene and the expression pattern of MdMYB110a. However, homologues of ABA-induced genes in apple were differentially expressed between pigmented and nonpigmented flesh derived from a single fruit, and ABA treatment in type 2 red-fleshed fruits led to the upregulation of MdMYB110a expression and the enhancement of anthocyanin production. These results strongly suggest that ABA, not ethylene, induced upregulation of MdMYB110a, the gene responsible for the type 2 red-flesh trait.

Engineered maize as a source of astaxanthin: processing and application as fish feed.

Astaxanthin from a transgenic maize line was evaluated as feed supplement source conferring effective pigmentation of rainbow trout flesh. An extraction procedure using ethanol together with the addition of vegetal oil was established. This resulted in an oily astaxanthin preparation which was not sufficiently concentrated for direct application to the feed. Therefore, a concentration process involving multiple phase partitioning steps was implemented to remove 90% of the oil. The resulting astaxanthin raw material contained non-esterified astaxanthin with 12% 4-keto zeaxanthin and 2% zeaxanthin as additional carotenoids. Isomeric analysis confirmed the exclusive presence of the 3S, 3'S astaxanthin enantiomer. The geometrical isomers were 89% all-E, 8% 13-Z and 3% 9-Z. The incorporation of the oily astaxanthin preparation into trout feed was performed to deliver 7mg/kg astaxanthin in the final feed formulation for the first 3.5weeks and 72mg/kg for the final 3.5weeks of the feeding trial. The resulting pigmentation of the trout fillets was determined by hue values with a colour meter and further confirmed by astaxanthin quantification. Pigmentation properties of the maize-produced natural astaxanthin incorporated to 3.5µg/gdw in the trout fillet resembles that of chemically synthesized astaxanthin. By comparing the relative carotenoid compositions in feed, flesh and feces, a preferential uptake of zeaxanthin and 4-keto zeaxanthin over astaxanthin was observed.

モモ赤肉品種における発育ステージ，光およびオーキシン輸送阻害剤が果皮および果肉の着色に及ぼす影響

モモ赤肉品種における発育ステージ，光およびオーキシン輸送阻害剤が果皮および果肉の着色に及ぼす影響

Leaves are important to obtain consistent red flesh pigmentation in Actinidia chinensis fruit

Red-fleshed Actinidia chinensis fruit are new to the market and consumers’ acceptance of these kiwifruit is subject to the development of a consistent red flesh pigmentation. We hypothesised that differences in the availability of source carbohydrate have an effect on the variation in fruit red colour within an orchard. In a block-red-fleshed (red colour in the inner and outer pericarp) genotype, effects of shoot types, parent cane types, vine rootstock, fruit position on the shoot, flowering time and light exposure on fruit flesh colour were evaluated. Vine vigour had a consistent effect on the outer pericarp colour of fruit. Fruit from the vines on the more vigorous rootstock (A. deliciosa ‘Bruno’ seedling) had the most intense and least variable outer pericarp red colour. In addition, fruit from long shoots on small diameter canes (10–15mm) were also the most intensely pigmented, whilst fruit position on the shoot, flowering time and fruit light exposure did not affect fruit flesh red colour. The vigour of vines due to rootstock, cane and shoot size also affected fruit growth and dry matter accumulation. These results suggest that, similarly to fruit growth (i.e. fresh weight and dry matter), vine vigour, carbohydrate availability and competition for resources between fruit and vegetative shoot growth have a putative role in red colour development in kiwifruit flesh. These finding can be used to develop optimised growing systems for new red-fleshed kiwifruit cultivars that minimise excessive shoot vigour to enhance red pigmentation of fruit flesh.

Ketocarotenoid Production in Soybean Seeds through Metabolic Engineering.

The pink or red ketocarotenoids, canthaxanthin and astaxanthin, are used as feed additives in the poultry and aquaculture industries as a source of egg yolk and flesh pigmentation, as farmed animals do not have access to the carotenoid sources of their wild counterparts. Because soybean is already an important component in animal feed, production of these carotenoids in soybean could be a cost-effective means of delivery. In order to characterize the ability of soybean seed to produce carotenoids, soybean cv. Jack was transformed with the crtB gene from Pantoea ananatis, which codes for phytoene synthase, an enzyme which catalyzes the first committed step in the carotenoid pathway. The crtB gene was engineered together in combinations with ketolase genes (crtW from Brevundimonas sp. strain SD212 and bkt1 from Haematococcus pluvialis) to produce ketocarotenoids; all genes were placed under the control of seed-specific promoters. HPLC results showed that canthaxanthin is present in the transgenic seeds at levels up to 52 μg/g dry weight. Transgenic seeds also accumulated other compounds in the carotenoid pathway, such as astaxanthin, lutein, β-carotene, phytoene, α-carotene, lycopene, and β-cryptoxanthin, whereas lutein was the only one of these detected in non-transgenic seeds. The accumulation of astaxanthin, which requires a β-carotene hydroxylase in addition to a β-carotene ketolase, in the transgenic seeds suggests that an endogenous soybean enzyme is able to work in combination with the ketolase transgene. Soybean seeds that accumulate ketocarotenoids could potentially be used in animal feed to reduce or eliminate the need for the costly addition of these compounds.

Phenotypic and genetic analysis of the German Malus Germplasm Collection in terms of type 1 and type 2 red-fleshed apples.

Red fruit flesh is a desirable trait in apple breeding, because red-fleshed apples are a novelty and therefore considered to be more attractive to consumers and contain more health beneficial compounds. The red fruit flesh coloration is based on an increased level of cyanidin 3-galactoside, an anthocyanin whose biosynthesis is regulated by the MYB-type transcription factors MdMYB10 or MdMYB110a, respectively. A repeated segment in the MdMYB10 promoter allele R6 results in a gain-of-function mutation visible as red pigmentation of fruit skin and flesh and all vegetative tissues. Red-fleshed apple genotypes containing this R6 allele belong to the type 1 red-fleshed apple, which is known to be linked to some negative traits like astringent taste and internal flesh browning disorder. In type 2 red-fleshed apples the fruit flesh coloration is not inevitably linked with skin and leaf color. This red-fleshed apple phenotype, which is a result of increased expression of MdMYB110a, seems to be more useful for breeding, but it can be found rather seldom. In the present study 357 Malus accessions of the German Malus Germplasm Collection were evaluated for red fruit flesh coloration and the presence of the MdMYB10 R1 (not mutated) and R6 promoter alleles. Among them a total of 40 accessions were identified which contain the R6 allele. 37 accessions showed a red coloration of the fruit flesh. All these accessions belong to type 1 red-fleshed apple. No type 2 red-fleshed apple could be found. Three accessions with R6 allele had non-red-fleshed apples. 312 other non-red-fleshed accessions contained only the R1 allele. Five non-red-fleshed accessions contained a new promoter allele with an unexpected size of ~1 kbp. Sequencing of this allele detected the insertion of a non-autonomous apple transposon.

Astaxanthin and Canthaxanthin (Xanthophyll) as Supplements in Rainbow Trout Diet: In Vivo Assessment of Residual Levels and Contributions to Human Health

Many studies have demonstrated that xanthophylls, such as astaxanthin, have beneficial effects in human health, and their use in food supplements is thus encouraged. Moreover, such nutrients are frequently used in aquaculture to meet consumer demand for salmonoid flesh pigmentation. In this study different xanthophyll administration protocols were tested to verify pigmentation properties and safety of such mixtures of additives in trout diet. Residues of xanthophylls in muscle samples were determined by HPLC-MS/MS, reaching levels of 3.70 ± 0.04 mg/kg (astaxanthin) and 1.21 ± 0.06 mg/kg (canthaxanthin) during a 56 day administration period. On the basis of the average fish consumption in the human diet, the highest astaxanthin and canthaxanthin concentrations detected in trout fillets could result in weekly intakes of 1.63 and 0.53 mg, respectively, in humans; these values are not sufficient to achieve the positive effects described by many authors, but their residues could still represent an important source of carotenoids, alternative to the use of synthetic dietary supplements.

Effects of dietary astaxanthins on pigmentation of flesh and tissue antioxidation of rainbow trout (Oncorhynchus mykiss)

The present study was conducted to evaluate the effects of three commercial astaxanthin preparations (100 mg kg−1 diet) with different solubilities in water, from DSM (Dutch State Mines), BASF (Badische Anilin and Soda Fabrik) and Wisdom Company on pigmentation of flesh and antioxidation of flesh, serum and liver in rainbow trout with an initial weight of 52.07 g. After 60 days of feeding, there were no significant differences in growth or flesh proximate composition of rainbow trout among groups (P > 0.05); the Salmo Fan score, redness and astaxanthin content of flesh in rainbow trout fed diets supplemented with astaxanthins were higher than those of the control group (P < 0.05). At 0, 12, 24, 48 and 72 h after thawing, the flesh malondialdehyde (MDA) content of the three astaxanthin groups was lower than that of the control group (P < 0.05). The total antioxidation capacity (T-AOC) of liver in the three astaxanthin groups was significantly higher, but serum catalase (CAT) activities were lower, than that of the control group (P < 0.05). The results indicate that addition of 100 mg kg−1 astaxanthin from DSM, BASF or Wisdom to the diet could improve flesh redness and liver T-AOC, reduce serum CAT, SOD and flesh MDA and extend the shelf life of flesh, in spite of the different solubilities of the three sources in water.

Effects of dietary supplementation with krill meal on pigmentation and quality of flesh of rainbow trout (Oncorhynchus mykiss)

Effects of administration of krill meal and synthetic astaxanthin during the finisher phase of the fattening cycle of rainbow trout on flesh pigmentation and quality traits were studied. The inclusion of krill meal increased the body weight and size and decreased the peri-visceral fat and visceral weight indices. The astaxanthin diet produced the highest accumulation of total carotenoids in the fillet compared to the krill meal diet: the difference was significant after 15 days of feeding (2.50 vs 2.10 mg/kg) till the end of the trial (5.00 vs 4.80 mg/kg). The same pattern was observed for astaxanthin concentration with the highest values in the fillets of fish fed the astaxanthin diet. Fillet lightness (L*) was not affected by trout diets whereas redness (a*) and yellowness (b*) were significantly higher in fish fed the astaxanthin diet until day 30 of the trial. Hue was not affected by feeding, whereas chroma was significantly higher in the fish fed astaxanthin throughout the trial except on day 45 of sampling. Trout fed the krill meal diet had a paler pink-red colour on the SalmoFan scale than those receiving the astaxanthin diet. No significant differences emerged in proximate composition and cholesterol content of trout in the two groups. The fatty acid profile of the fillets reflected the fatty acids of the diets administered to the trout: eicosapentaenoic, docosa-hexaenoic and docosapentaenoic acids and total n-3 polyunsaturated fatty acids were significantly higher in the fish fed the krill meal.

Flavonoid profiling and transcriptome analysis reveals new gene-metabolite correlations in tubers of Solanum tuberosum L.

Anthocyanin content of potato tubers is a trait that is attracting increasing attention as the potential nutritional benefits of this class of compound become apparent. However, our understanding of potato tuber anthocyanin accumulation is not complete. The aim of this study was to use a potato microarray to investigate gene expression patterns associated with the accumulation of purple tuber anthocyanins. The advanced potato selections, CO97216-3P/PW and CO97227-2P/PW, developed by conventional breeding procedures, produced tubers with incomplete expression of tuber flesh pigmentation. This feature permits sampling pigmented and non-pigmented tissues from the same tubers, in essence, isolating the factors responsible for pigmentation from confounding genetic, environmental, and developmental effects. An examination of the transcriptome, coupled with metabolite data from purple pigmented sectors and from non-pigmented sectors of the same tuber, was undertaken to identify these genes whose expression correlated with elevated or altered polyphenol composition. Combined with a similar study using eight other conventional cultivars and advanced selections with different pigmentation, it was possible to produce a refined list of only 27 genes that were consistently differentially expressed in purple tuber tissues compared with white. Within this list are several new candidate genes that are likely to impact on tuber anthocyanin accumulation, including a gene encoding a novel single domain MYB transcription factor.

Genetic analysis of pigmented tuber flesh in potato

Interest in anthocyanin-pigmented potato tuber flesh is increasing. To genetically map and characterize loci that influence this trait, diploid potato clone 10618-01, which has partially pigmented flesh, was crossed with diploid 320-02, which has white flesh. Almost all progeny exhibited purple coloration in the flesh, with some clones having only a small percentage of tissue pigmented, other clones having most tissue pigmented, and the majority of clones showing intermediate color phenotypes. The two parents and 228 progeny were genotyped with 493 AFLP, 8 CAPS, and 13 SSR markers. QTLs influencing extent of flesh pigmentation were detected on chromosomes 5, 8, and 9. The potato homolog of Petuniaan1, a basic helix-loop-helix (bHLH) transcriptional regulator of anthocyanin biosynthesis, was found to co-localize with the QTL on chromosome 9. A CAPS marker based on this gene was used to evaluate a collection of 21 tetraploid potato clones with highly or fully pigmented red or purple flesh, as well as 53 cultivars with white or yellow flesh. All 21 pigmented-flesh clones shared a marker allele that was present in only 21 of the 53 white and yellow clones, suggesting that a common bHLH allele contributes toward, although it is clearly not sufficient for, highly or fully pigmented tuber flesh in cultivated potato.

Cancer Prevention of Anthocyanins in the Purple Sweetpotato bred in Kansas

Anthocyanins are versatile and plentiful flavonoid pigments that account for the purple color in may plant foods such as red grapes, berries, red cabbages, and purple sweetpotato. Although anthocyanins have been epidemiologically associated with reduced cancer risk, the anticancer ability of the purple sweetpotato has not been well investigated. Considering the high contents of anthocyanin in the purple sweetpotato, we have bred purple‐fleshed sweetpotato cultivars using seeds from controlled crosses provided by the International Potato Center in Lima, Peru. Over 2000 seedlings from four full‐sib progenies cultured at the John C. Pair Horticulture Research Center, Kansas, have been segregated by multiple traits based upon flesh pigmentation and fiber contents. We and determined the prominent anthocyanin contents by HPLC‐MS, including cyanidin 3‐sophoroside‐5‐glucoside (m/z 774), p‐hydroxybenzoylated cyanidin 3‐sophoroside‐5‐glucoside (m/z 894), caffeoylated cyanidin 3‐sophoroside‐5‐glucoside (m/z 908), and peonidin 3‐(6,6′‐caffeoyl‐p‐hydroxybenzoylsophoroside)‐5‐glucoside (m/z 1055). Furthermore, the selected purple sweetpotato extracts with high levels of anthocyanins have been assessed in the human colon cancer SW480 cells for potential anticancer mechanisms. Better understanding of the underlying mechanisms may provide scientific evidence and health benefits of purple sweetpotato grown in Kansas.

Impact of Different Dietary Phospholipid Levels on Cholesterol and Canthaxanthin Lipoprotein−Serum Transport and Muscle Deposition in Rainbow Trout

The study was designed to assess the effect of a progressive increase of dietary phospholipid (PL) levels in the transport of cholesterol and canthaxanthin by serum lipoproteins and their deposition in trout muscle. Three groups of 30 immature rainbow trouts, in triplicate, with a mean body weight of 195 g were fed three experimental diets containing 0, 4, and 8% extra PL contents for 6 weeks. The two major lipoprotein classes in rainbow trout were HDL and LDL. Both lipoproteins were the main transporters of serum canthaxanthin, whereas cholesterol was transported principally by LDL. Serum cholesterol contents remained constant, whereas serum canthaxanthin was increased when the PL amount augmented. In muscle, PL seemed not to have an effect on cholesterol and canthaxanthin deposition. Therefore, as an extra-PL contribution in the diet did not increase relative percentages of cholesterol and/or canthaxanthin in trout muscle, the results support the hypothesis that dietary extra-PL addition is not necessary to increase cholesterol and canthaxanthin and thus fish flesh pigmentation. However, a saturation effect of diet PL contents was found on muscle canthaxanthin deposition.

Why are salmonids pink?

Pigmented flesh, a trait uniquely present in four of the 10 genera of salmonid fishes, is caused by the ubiquitous capacity of these genera for accumulating dietary carotenoids in muscle tissue. Here we combine life history reasoning with current knowledge of carotenoid metabolism to suggest a possible evolutionary scenario accounting for the emergence and maintenance of this phenotype. We claim that a basal carotenoid metabolism and a hormonally controlled targeted degradation of muscle tissue during maturation were established before the anadromous life style and that these proximal features were concomitantly exploited by natural selection in an ancestral anadromous and nest-making salmonid. Three different selection regimes are suggested to account for available empirical data concerning emergence, as well as maintenance, of the flesh pigmentation trait: a primary one driven by the need for enhanced somatic maintenance accompanying nest making under starving conditions, a secondary one driven by sexual selection, and a tertiary one driven by exposure to a meager carotenoid diet in nonanadromous freshwater populations. Finally, an experimental research program thought to be instrumental for fully resolving this evolutionary puzzle is suggested.

(265) DNA Sequence Variation within the Promoter of VvmybA1 Associates with Flesh Pigmentation of Intensely Colored Grape Varieties

Grapevine (Vitis vinifera L.) is one of our oldest domesticated crops and economically the most important cultivated fruit crop in the world. Cultivated grapes show substantial diversity in fruit color, including: varying shades of black, red, pink, grey, white, and types with pigmented berry flesh. The majority of V. vinifera cultivars only possess anthocyanin pigmentation in the skin of the berry (also known as teinturiers). However, some cultivars possess berries with intensely pigmented flesh as well as skin, which is often also associated with greater pigmentation of vegetative tissues. The genetic control and inheritance of fruit color in grapevine is poorly understood, despite evidence that the primary determination of anthocyanin production appears to be controlled by a single dominant locus in V. vinifera with white fruit being a recessive character. Recently, it has been shown that the presence of Gret1, a Ty3-gypsy-type retro-transposon in the promoter region of a myb-like regulatory gene is present in white-fruited cultivars of V. vinifera and that allelic variation in this gene associates with several qualitative classes of grape fruit color. It has been observed that the red-flesh berry phenotype is similarly controlled by a single dominant locus. Considering the association of variation in VvmybA1 with grape berry skin color, it was hypothesized that DNA sequence variation in VvmybA1 would also be associated with genotypes showing intensely pigmented berry flesh. In this study, we show that allelic variation in VvmybA1 associates with the teinturier phenotype both in a panel of accessions possessing red-flesh as well as in a population of full-sibs segregating for the red-flesh phenotype.

The use of additional lighting and artificial photoperiods to recondition early maturing Atlantic salmon (Salmo salar) in Tasmania

Salmonid culture in Tasmania experiences high rates of early maturation due to the rapid growth rates achieved under favorable environmental conditions. The present study investigates the use of artificial photoperiod to recondition previously mature Atlantic salmon to provide a larger fish with higher market value. Individual groups of previously mature female Atlantic salmon (Salmo salar) were put under 24 hour artificial light from either May, June, July or maintained under ambient conditions during the austral winter. Fish maintained under lights attained a reversion from dark skin pigmentation, typical of mature individuals, to a silver sea-going coloration more rapidly than the control group. In addition flesh pigmentation, ovarian absorption and body wall thickness was significantly greater than that of the control fish resulting in a higher market price. The study demonstrates that artificial lights can facilitate the reconditioning of previously mature Atlantic salmon under southern hemisphere conditions.

Seasonality of oocyte development and pigmentation in Atlantic salmon, Salmo salar

This study identifies the presence of a spring drop of flesh pigmentation that coincided with oocyte atresia in Atlantic salmon and outlines the potential influence that additional lighting and feed management strategies can have on these processes.

Pigmentation and Composition of Flesh of Atlantic Salmon Fed Diets Supplemented with the YeastPhaffia rhodozyma

Abstract In a pigmentation trial, Atlantic salmon Salmo salar in ocean pens were fed diets supplemented with the red yeast Phaffia rhodozyma, a control diet supplemented with synthetic astaxanthin, and a nonpigmented control diet. Yeast diets contained spray-dried untreated P. rhodozyma, heat-treated and spray-dried P. rhodozyma, and heat-treated and chemically treated spray-dried P. rhodozyma. Growth, weight, and fork length of all fish increased linearly with feeding and were not significantly different at the end of the study. Astaxanthin concentration in all pigmented fish increased linearly and ranged from 3.26 to 3.78 mg/kg after 150 d of feeding. Apart from the nonpigmented diet, astaxanthin concentration was not significantly different between fish fed the untreated or treated red yeast and those fed the synthetic astaxanthin diet (control). Assessment of astaxanthin isomers corroborated the assimilation of the (3R,3′R) isomer from all P. rhodozyma diets. Moisture, ash, and protein in all fish dec...

The effect of timing and duration of feeding astaxanthin on the development and variation of fillet colour and efficiency of pigmentation in rainbow trout ( Oncorhynchus mykiss)

The efficiency of pigmentation and the variation and development of fillet colour were assessed in rainbow trout fed astaxanthin (Ax) enriched diets at different stages of fry development and for different periods of time. Triplicate groups of 165 rainbow trout were fed a fish meal-based diet containing 31 mg/kg Ax at start weights of 6.5±0.5 g (A), 25±2 g (B), 120±5 g (C) until reaching a market weight of 400 g. A control group received a diet without Ax throughout the experiment. The chromaticity of the dorsal and Norwegian Quality Cut (NQC) regions of the fillets were assessed at regular weight intervals by tristimuli colorimetry. The Ax concentration of the NQC region was determined by HPLC. The final flesh Ax concentrations in the pigmented groups ranged from 5.5±0.3 μg/g in group C to 8.0±0.5 μg/g in group B. There were large variations in fillet colour irrespective of the timing and duration of Ax intake and the variations were significantly higher in the dorsal muscle compared to that of the NQC. Inter and intra-fillet variations in pigmentation were reduced with increases in wet weight, irrespective of the duration of pigment intake. There appears to be an innate variation of 20–25% in flesh pigmentation in any one stock at a market weight of 400 g. Irrespective of the timing and duration of Ax intake, the initial development of colour was greater in the NQC region, followed by the muscle along the lateral line and dorsal region, respectively. Pigmentation of the NQC region occurred faster and remained at a higher level than that of the dorsal region.