Yellow Flesh Color Research Articles

Identification of a novel locus C2 controlling canary yellow flesh color in watermelons.

The flesh color of watermelon is an important trait that is determined by carotenoid composition and affects consumers' fruit desirability. Although a complete dominant control by C locus (Cllcyb) for canary yellow flesh (CY) over red flesh has been reported, red and CY colors frequently appear as a mixed pattern in the same flesh (incomplete canary yellow, ICY) in F1 and inbred lines carrying dominant C alleles. Therefore, we examined the genetic control of the mixed color pattern in ICY using whole-genome resequencing of three ICY (ICY group) and three CY inbred lines (CY group), as well as genetic linkage mapping of an F2 population. The segregation pattern in 135 F2 plants indicated that CY is controlled by a single locus (named C 2) dominant over ICY. The whole-genome resequencing of ICY and CY inbred lines revealed an ICY/CY-specific region of approximately 27.60-27.88Mb on Chr. 2 that was polymorphic between the ICY and CY groups. Our genetic map, using nine cleaved amplified polymorphic sequence markers developed based on the single-nucleotide polymorphisms from the ICY/CY-specific region, confirmed that C 2 is located on Chr. 2 and cosegregated with the marker (M7) derived from a non-synonymous single-nucleotide polymorphism of the pentatricopeptide repeat (PPR) gene (ClPPR, Cla97C02G039880). Additionally, 27 watermelon inbred lines of ICY, CY, and red flesh were evaluated using previously reported Cllcyb (C locus)-based markers and our C 2 locus-linked ClPPR-based marker (M7). As a result, dominant alleles at the C 2 locus were required to produce CY, in addition to dominant alleles at the C locus, while a recessive homozygous genotype at the C locus gave the red flesh irrespective of the genotype at the C 2 locus. Using a ClPPR-based cleaved amplified polymorphic sequence developed in this study and Cllcyb-based markers, watermelon cultivars with CY, ICY, and red flesh could be successfully discerned, implying that the combined use of these markers will be efficient for marker-assisted selection of flesh color in watermelon breeding.

Exploration and characterization of tinombo local garlic, Central Sulawesi

Most of Indonesia’s garlic needs are fulfilled by imported (97%). The government focuses on local garlic for seed prospects and gives a mandatory for importers to plant it to increase domestic production. Beside of using registered local varieties, it is also intended for local varieties which have not been registered, to be developed especially by local farmers. Exploration and characterization are very necessary so that the presence of local varieties of garlic in each region is known. This study aims to explore and characterize the local garlics in Central Sulawesi. The research was carried out in March 2020, located in Parigi Moutong Regency. The research used survey method, while the observations of plant morphology and agronomy using a Horticultural Plant Characterization Guidebook. The research found a local variety of garlic namely Tinombo Variety. Apart from being a cooking spice, Tinombo variety also used as a biopharmaceutical. The result of the characterization shows that Tinombo variety has light green leaf color, pale yellow flesh color, very sharp aroma, 14-21 cloves per bulb, 2-3 t/ha production while the yield potential is 7.6 t/ha. The harvest age is 5-6 months, and it is suitable in the highlands. The obstacle for farmers is the difficulty of the access to and from the field, thus the price of garlic is expensive. The cultivation technology is still conventional and does not use fertilizers. This local variety has a high chance to increase its productivity with the application of appropriate and site-specific technologies.

Quality Characteristics of Sweet Potato Jelly Prepared Using the Enzymatic Saccharification Method.

In this study, jelly was prepared using saccharified sweet potatoes without sugar, and its quality characteristics were compared according to the sweet potato cultivar. Three sweet potato varieties, namely Juwhangmi (orange color), Sinjami (purple color), and Daeyumi (yellow flesh color), were used. The total free sugar and glucose contents of the hydrolysate were found to increase during the enzyme treatment. However, no differences in the moisture, total soluble solids, or textural properties were found among the sweet potato cultivars. Sinjami had high total polyphenol and flavonoid contents of 446.14 mg GAE/100 g and 243.59 mg CE/100 g, respectively, and it had the highest antioxidant activity among the cultivars. Based on the sensory evaluation, an overall preference appeared in the order of Daeyumi, Sinjami, and Juwhangmi cultivars. This result shows that jelly can be manufactured by saccharifying sweet potatoes, and it was confirmed that the characteristics of raw sweet potatoes had a great influence on the quality characteristics of the jelly. Further, the characteristics of raw sweet potatoes had a remarkable influence on the quality characteristics of the jelly.

Assessment of maturity stage and stability of new Indonesian melon cultivar ‘Melona’ based on ISSR markers and morphological characteristics

Abstract. Yusuf AF, Alfiyani A, Salsabila TAS, Kusnanda PS, Hidayati IN, Daryono BS. 2023. Assessment of maturity stage and stability of new Indonesian melon cultivar ‘Melona’ based on ISSR markers and morphological characteristics. Biodiversitas 24: 308-316. Market preferences for horticultural products determine the product’s selling value and absorption. One market criterion often used for the quality of horticultural products is color and maturity level. Color differences can provide a representation of the metabolites contained in a product. This study provides a standard for assessing melons' maturity level, which will be helpful as a benchmark for Indonesian consumer acceptance. In addition, this study also provides information on the stability of the character of the new cultivar 'Melona' from several generations of crosses to obtain superior cultivars. Assessment of maturity level based on color development in 'Melona' is divided into five stages. In the first and second stage, fruit was dominated by green color with Increasing fruit volume. The color change begins in the third stage. in the third stage and the following phases, there is an increase in the accumulation of beta-carotene and characterized by the dominance of orange instead of green. Maximum ripe of ‘Melona’ is characterized by strong yellow lobes, creamy-white interlobes, and orange flesh color. A molecular analysis employing four ISSR primers (UBC-807, UBC-808, UBC-811, and UBC-824) resulted in high uniformity and low genetic variation in the hybrid and parent lines genotype. Analysis resulted a total of 42 DNA fragments with only one polymorphic DNA fragment. The polymorphic DNA fragment was 2,300 bp in size and was found in the female accession 'Melona' and the hybrid 'Melona' based on the UBC-808 primer. The numerical phenetic relationship between male, female and hybrid accession melon cultivars is very close (above 97.6%) and indicated that the melona cultivars were stable.

Identification of chromosome region and candidate genes for canary-yellow flesh (Cyf) locus in watermelon (Citrullus lanatus)

Genetic control of fruit flesh color in watermelon is complex, and significant knowledge gaps still exist. In the present study, we investigated the genetic basis of canary-yellow flesh color in watermelon inbred line PI 635597 using a segregating population derived from a cross between PI 635597 and another inbred line, Cream of Saskatchewan (pale yellow flesh color). We showed that a single dominant gene controls the canary-yellow flesh color for the Cyf (canary-yellow flesh) trait. Bulk segregant analysis (BSA) and fine genetic mapping narrowed down the Cyf locus to a 79.62-kb region on chromosome 6, which harbors 10 predicted genes. Sequence variation analysis in the promoter and coding regions and gene expression analysis in both parental lines and selected watermelon accessions with diverse fruit flesh colors support Cla97C06G122050 (unknown protein) and Cla97C06G122120 (pentatricopeptide repeat) as predicted candidate genes for the Cyf locus. Marker-assisted selection and sequence alignment showed that the Cyf locus could differentiate canary-yellow flesh and pale-yellow flesh. Our results indicate that the Cyf locus might be responsible for canary-yellow flesh color and carotenoid accumulation levels.

Diversity Assessment Among Seventy-Four Potato Genotypes for Selection in Breeding Program

Sustainable production of food crops relies on germplasm improvement and genetic diversity. In the present study, seventy-four potato genotypes were evaluated for diversity analysis during autumn 2017-2018 and 2018-2019 at NARC, Islamabad. Our results showed significant diversity in qualitative traits with reference to skin color of five types (Red, yellowish, brown, light yellow, light brown skin color tubers=5), three types of flesh color (Yellow, cream and white flesh color tubers=3), three sizes of tubers (Medium, small and large size tubers=3) and four shape of tuber (Oval, round, oblong, elliptic= 4 shapes) and four different eyes color (Brown, light brown, dark red and yellow eyes color=4). Potato genotype under study had very high genetic variance for quantitative attributes including weight of tuber per plant and weight number of tubers per lane, leaf area and plant height. Significant positive correlation was observed between number of tubers per plant (TPP) with number of eyes on tubers (r = 0.241) and number of tubers per lane (TPL) (r = 0.349). Plant height was found significantly positive correlated with leaf area (r= 0.456), germination percentage (r = 0.255) and weight of tubers per plant (r = 0.307). Leaf area (LA) showed positive significant correlation with number of tubers per plant (r = 0.466) and weight of tubers per plant (r = 0.263), yield and harvest index (r = 0.798, 0.755, 0.255). Weight of tubers per lane (WTL) showed positive correlation with weight of tubers per plant (r = 0.387). Regarding the interrelation between the traits and genotypes, the first two principal component axes (PC1, 24.83% and PC2, 23.46%) accounted for about 48.29% of the total variability reflecting the complexity of the variation between the plotted traits of genotypes. The present study will be useful for the precise selection for effective breeding program.

Evaluation of yields on new varieties of hybrid watermelon

Watermelon is a very important commodity in food security, especially horticultural products. Watermelon hybrid varieties are proven to be able to increase production and income for watermelon farmers. Watermelon breeding continues to produce superior varieties. Pure strains of watermelon as parents in the propagation or production of hybrid watermelon seeds, are necessary for crosses between parents to produce F1 hybrids. Evaluation and selectionare important stages in a plant breeding program. The purpose of this study was to obtain information on theproduction of hybrid watermelons from the research team of the Politeknik Negeri Lampung watermelon breeder.This study used a Randomized Block Design with nine treatments (varieties) repeated three times. The results of the observations were analyzed using the LSD test at the 5% level. The results showed that the varieties WM200701 and WM200702 had dark skin color and red flesh. Sweetness level data were significantly different by 9.3 °brix andl0.15 °brix when compared to control (8.9 °brix). Varieties WM 200703 and WM 200706 have bright green skin color with thin stripes with red and yellow flesh color. WM 200704 and WM 200705 have red flesh and dark green skin with thick striations. WM 200703 has the highest fruit weight of 4.63 kg per fruit. The six hybrid varieties tested have the potential to be submitted for registration of the F1 hybrid watermelon variety.

Phenolic profiling reveals the metabolite basis of flesh colour and fresh‐cut browning in apple fruit

SummaryFlesh colour, which is affected by cultivars and browning, can largely impact consumer acceptance in fresh‐cut apples. The study profiled phenolic metabolites from apple flesh of twenty‐three cultivars by widely targeted metabolomics. Comparison among white‐ and yellow‐fleshed cultivars showed fifteen phenolics, mainly quercetin 3‐O‐glucoside, hyperoside, hesperetin 5‐O‐glucoside and cymaroside, in white‐fleshed apples were significantly higher than those in yellow‐fleshed apples. It may indicate a metabolite basis of yellow and white flesh colour, and better potential nutrition in white‐fleshed apples. In addition, ten phenolic metabolites including five cyanidin glycosides showed significant differences between the highest and the lowest browning groups, indicating them may be crucial in browning of fresh‐cut apple. This work elucidates the differences of phenolic profiles among apple cultivars with different flesh colour and provides useful data to evaluate the suitability of apple for fresh‐cut processing.

Yellow Tainting of Flesh in Pangasius (Pangasianodon hypophthalmus): Origin of the Color and Procedures for Removal

Pangasius (Pangasianodon hypophthalmus) is a commonly farmed fish in ponds in Bangladesh but its yellow flesh color creates a barrier for export. Here, we investigated if feed ingredients and environmental parameters might impact yellow tainting of the flesh. In experimental feeds, maize (a typical ingredient in commercial feeds) was replaced by soybean meal, and frequent exchange of pond water was introduced. Chemical analyses showed that the commercial feed was high in carotenoids (lutein, zeaxanthin and β-carotene; 18.8 mg/kg) as compared to the experimental feeds (≤1 mg carotenoids/kg). After feeding the fish commercial and experimental feeds for 9 months, the content of total carotenoids in the flesh was reduced by 48% to 64% and visual yellowness by up to 47% by the experimental feeds. Weekly or biweekly water exchange in combination with the experimental feeds further reduced the yellow coloration to 22% relative to fish given commercial feed and without water exchange. Our study demonstrates that pangasius with white flesh can be produced in Bangladesh by combining feeds low in pigments with frequent water exchange. 

Quality Evaluation, Phytochemical Characteristics and Estimation of Beta-Carotene Hydroxylase 2 (Chy2) Alleles of Interspecific Potato Hybrids

Potatoes contain antioxidants such as flavonoids, carotenoids and ascorbic acid. High level consumption worldwide makes potato a valuable source of phytonutrients. Developing new potato varieties with high nutritional value in combination with resistance to pathogens is an important task. In this study, 25 interspecific potato hybrids with resistance to Synchytrium endobioticum, common scab, silver scab, rhizoctonia, nematodes and PVY were evaluated for total phenolics, total flavonoids, total carotenoids, ascorbic acid contents and antioxidant activity. The identification of the dominant allele related with yellow flesh color at the Chy locus was also performed by the specific CAPS marker. Total protein content was detected and ranged from 8.19 ± 0.59 to 30.17 ± 4.56 mg/g dry weight (DW). Total starch and total carbohydrate contents were in the range of 9.0–21.0% and 73.21 ± 20.94–676.36 ± 195.28, respectively. Total phenolic content of hybrids varied from 8.45 to 82.75 mg/100 g, and total flavonoids content—from 0.64 to 9.67 mg/100 g DW. It is possible to distinguish samples with high protein and carbohydrate contents, high level of substances with antioxidant activity and characterized by resistance to pathogens. Quality evaluation has shown that some of the samples have a high potential for processing and chip production in combination with high eating qualities. These samples can be used in breeding programs to develope varieties resistant to pathogens and with high nutritional value.

Biochemical and molecular factors governing flesh-color development in two yellow-fleshed kiwifruit cultivars

To identify the biochemical and molecular factors causing flesh-color variation between two yellow-flesh kiwifruit cultivars 'Jinshi 1′ and 'Jinyan', the composition of carotenoids and chlorophyll, and associated gene expression profile in their pulp were investigated during fruit development. At harvest, ‘Jinshi 1′ exhibited brighter yellow flesh than ‘Hort16A’ with a lower color hue angle, although they had a similar total carotenoid content. At the molecular level, ‘Jinshi 1′ exhibited higher expression level of chlorophyll catabolic genes (CBR, PPH, and PAO), leading to lower accumulation of chlorophyll in the flesh. Meanwhile, higher expression levels of NCED1 resulted in greater carotenoid degradation in ‘Hort16A’. In addition, ‘Hort16A’ had a higher content of lutein, zeaxanthin and β-carotene, whereas ‘Jinshi 1′ had specific β-cryptoxanthin on ripening, accordingly, the expression of CHYB1, which encodes the enzyme for the formation of zeaxanthin and β-cryptoxanthin, was higher during the last developmental stage in ‘Jinshi 1′ than in ‘Hort16A’. These results suggested that the higher carotenoid/chlorophyll ratio, as well as the higher β-cryptoxanthin proportion are the important reasons for the brighter yellow flesh color.

Assessment of the roles and farmer-preferred traits of sweetpotato in a crop-livestock farming system in Rwanda: implications for breeding dual-purpose varieties

Abstract In Rwanda, sweetpotato (Ipomoea batatas [L.] Lam) is a highly valued crop in a crop-livestock mixed farming system. The objective of this study was to assess the role of sweetpotato in the crop-livestock farming system, to identify farmer-preferred traits, and to establish farmer-led priorities in breeding dual-purpose varieties (DPVs) in Rwanda. A participatory rural appraisal (PRA) study was conducted in three selected districts of Rwanda, namely, Bugesera, Huye, and Nyagatare. Data on the uses of sweetpotato and farmers’ trait preferences in sweetpotato varieties were collected and analysed. In Huye District, a high percent (56.7%) of respondents consumed sweetpotato every day, followed by Nyagatare with 53.3% consuming it at least twice a week. Most farmers (52.2%) used sweetpotato vines for livestock feed, depending on their availability. All respondents wanted to grow new sweetpotato varieties with improved root production combined with high aboveground biomass. About 87.7, 66.6, 56.6, and 51.1% of the respondents indicated that root-related traits of the crop such as high dry matter content (DMC), red skin colour, marketable root size, and yellow flesh colour were additional preferred traits, respectively. Therefore, farmers-preferred DPVs with improved root and green fodder yields could be developed to enhance the sustainable production and adoption of sweetpotato in a mixed farming system in Rwanda.

QUALITY INDICATORS FOR MODIFIED ATMOSPHERE PACKAGING (MAP) STORAGE OF HIGH-QUALITY EUROPEAN PLUM (PRUNUS DOMESTICA L.) CULTIVARS

The use of quality indicators is crucial in selling plums in more distant markets and the evaluation of freshness through multiple index is fundamental to evaluate the goodness of the storage technique. In this study we evaluated the quality of two european plums cultivars ('Ramasin' and 'Ariddo di Core' with purple and yellow flesh colour respectively) after modified atmosphere packaging (MAP) storage, through the selection of the most appropriate indicators. The headspace gas composition, the flesh fruit firmness (FFF), the soluble solid content (SSC), the titratable acidity (TA), the colour and the chlorophyll content of plums wrapped with 5 different films (F1, F2, F3, F4 and F5) were evaluated for up 21 days of storage (at 1±1°C and 90-95% relative humidity). For both cultivars, the multilayered films (F1 and F2, 90 and 65 µm respectively) offered better effectiveness over other films. The total chlorophyll concentration, showing a good correlation with the colorimetric parameters of luminance (L*) and chroma (respectively R 2 =0.92 and R 2 = 0.96) confirmed, in the case of the Ariddo di Core cultivar, the results obtained by monitoring other parameters thus highlighting the usefulness of integrating multiple indexes in evaluating the performance of the storage methods used.

THE NEW YELLOW-FLESHED KIWIFRUIT (ACTINIDIA CHINENSIS PL.) 'SORELI': CONCLUSIONS FROM SIX YEARS OF CULTIVATION IN DIFFERENT CLIMATIC AREAS

‘Soreli’ (meaning “sun” in the local language) is a selection of tetraploid Actinidia chinensis developed at the University of Udine and released in 2008. The main characteristics are: heavy cropping, large fruit size, and yellow flesh color. We report in the present paper the results of six years of observation (2007-2012) in three different locations from North to Southern-Italy. Budburst occurred 4-17 days before ‘Hayward’, with the earlier bud burst recorded in the South. Flowering time occurred almost constantly two weeks before ‘Hayward’, but in a range of dates encompassing up to three weeks in the different seasons and locations. Flowers were usually single. Fruit weight at harvest ranged from 85 to 147 g, according to location and season with the lowest values recorded in absence of artificial pollination. Orchards of the trial were not sprayed with plant growth regulators (PGR). Harvesting date, fixed by the protocol when fruit reached 8.0°Brix, ranged up to 25 days, with the extreme dates represented by September 23 and October 18. Soluble solid content averaged from 12.5 to 15.7, with erratic influence of location and season. Fruit quality, evaluated through a taste panel, was compared with two controls, ‘Hayward’ (green) and ‘Jintao’ (yellow) grown together with ‘Soreli’ in a single location. Authors discuss the marketing strategies that could be developed following the data on cropping and fruit quality of this new kiwifruit cultivar as observed in locations that greatly differed from each other for winter chilling unit accumulation, degree days, temperatures, rainfall and other climatic and soil parameters.

CONSUMER PREFERENCES FOR PAWPAW IN IBADAN METROPOLIS

Pawpaw is one of the tropical fruits that are produced and consumed in various forms all through the year in Nigeria. A field research survey was undertaken to study the consumer preference and analyze consumer behaviour regarding pawpaw in Ibadan, Oyo State Nigeria, during the period of June to November 2013. Two hundred and fifty consumers were selected in the metropolis at random for the interview using structured questionnaires. Data were analyzed using descriptive statistics and chi-square. The result of the analysis showed that 52% of the respondents were female while 48% were male. Most of the respondents were between 25 and 44 years (68.4%) and married (74.8%). Study revealed 65.6% consumed pawpaw in both peak and lean seasons attributing their reasons to health benefits >taste >colour>price. Preferred attributes of pawpaw include: oblong shape (36.4%), medium size (41.2%), yellow flesh colour (53.6%) and slightly green fruit colour (41.2%). The chi-square values showed that there was no significant difference in the response on shape (p>0.05). However, responses about size, flesh colour, fruit colour and amount willing to pay differ significantly (p price>size>colour > shape determine purchase decision of pawpaw. The study recommends intensive research into development and multiplication of pawpaw varieties that have appealing characteristics to consumers for increased demand.

A chimeric transcript containing Psy1 and a potential mRNA is associated with yellow flesh color in tomato accession PI 114490

Carotenoid content is the primary determinant of fruit color that affects nutritional value and appearance in tomato. Phytoene synthase (PSY) is the key regulatory enzyme in the carotenoid biosynthesis pathway. Absent function of PSY1 in tomato fruit results in yellow flesh phenotype. We, here, report that two different transcripts, a wild-type (Psy1) and a chimeric mRNA (Psy1/Unknown), exist in a yellow-fruited tomato accession PI 114490. Psy1/Unknown is generated by joining exons from two different genes, Psy1 and an unknown gene, transcribed using both complementary DNA strands. The Psy1 shows low expression in the fruit of PI 114490, while the expression of Psy1/Unknown in the fruit of PI 114490 shows the same pattern as Psy1 in red fruit. The PSY1/Unknown has a lower function than PSY1 in a bacterial expression system. Coincidence of one single-nucleotide polymorphism (SNP) in the fourth intron and one simple sequence repeat (SSR) with 19 AT repeats in the downstream sequence of Psy1 gene with Psy1/Unknown in a set of yellow-fruited tomato lines indicates that Psy1/Unknown might be caused by the SNP and/or SSR. One possible explanation of these observations is trans-splicing. Severely reduced Psy1 transcript caused by Psy1/Unknown results in low accumulation of carotenoid and yellow flesh in PI 114490.

Postharvest performance of the yellow-fleshed ‘Hort16A’ kiwifruit in relation to fruit maturation

Postharvest performance of fruit is dependent on the maturity or physiological state of the fruit at harvest in conjunction with the postharvest management applied. For yellow-fleshed kiwifruit, the flesh colour is a significant quality attribute, and for ‘Hort16A’, flesh colour has been used for timing harvest. Variability in the postharvest performance of ‘Hort16A’ kiwifruit suggests that flesh colour alone is not as strongly indicative of postharvest performance as soluble solids content (SSC) was found to be for ‘Hayward’ kiwifruit 30 years ago. The postharvest performance of ‘Hort16A’ kiwifruit, assessed as the fruit firmness and chilling injury expression during storage, has been associated with a range of fruit characteristics: flesh colour, SSC, firmness, seed colour, fresh weight, dry matter, starch and soluble carbohydrates measured at harvest throughout maturation. The changing responses of the fruit SSC to temperature, and softening to ethylene, have also been determined. The data illustrate the complex nature of ‘Hort16A’ fruit maturation, even when looking only at simple, easy-to-measure fruit attributes. While a yellow flesh colour is a commercial necessity for ‘Hort16A’ kiwifruit, flesh colour is not a robust indicator of postharvest performance and is not tightly linked to SSC or firmness. Changes in the capacity of fruit to respond to temperature or ethylene are not reflected in on-vine changes. Softening in storage is strongly linked to the softening rate occurring on the vine at the time of harvest. Any association between at-harvest characteristics and chilling susceptibility is less clear, and chilling tolerance appears more associated with the completion of growth and carbohydrate accumulation than with increased soluble solids accumulation rates as in ‘Hayward’. Approaches to extend the understanding of the link between maturation, harvest indices and postharvest performance are discussed.

Caracterização de frutos de cultivares de pessegueiro na Zona da Mata Mineira

This study aimed to evaluate physical and chemical characteristics of fruits of 14 peach cultivars with yellow flesh named Aurora 1, Aurora 2, Biuti, Capdeboscq, Campinas 1, Diamante, Douradão, Dourado 1, Lake City, Maciel, Rei da Conserva, Régis and Tropic Beauty. They were introduced in the experimental orchard of the Federal University of Viçosa (UFV), Viçosa-MG. The experiment was conducted during the 2011 season, in a completely randomized design with 14 treatments (cultivars), three replications and 10 fruits per plot. Fruit with more intense yellow skin coloration were found in cultivars Lake City and Régis and the cultivars Aurora 1, Aurora 2, Capdeboscq, Diamante, Douradão, Dourado 1, Maciel, Régis and Tropic Beauty had yellow flesh color more intense. The fruits of cultivars Capdeboscq, Maciel and Rei da Conserva had, in general, higher fruit weight and diameter. The fruits of cultivars Douradão and Dourado 1 had a better balance between acidity and soluble solids and higher content of vitamin C. Higher levels of carotenoids were found in cultivars Capdeboscq, Campinas 1, Régis and Rei da Conserva.

Inactivation of a Gene Encoding Carotenoid Cleavage Dioxygenase (CCD4) Leads to Carotenoid-Based Yellow Coloration of Fruit Flesh and Leaf Midvein in Peach

Yellow fruit flesh color, resulting from the accumulation of carotenoids, is one of the most important commercial traits of peach. Yellow flesh is controlled by a single locus (Y), with white flesh dominant over yellow flesh. In this study, the Y locus was narrowed to a 2.6-cM interval flanked by two markers, SSRy and W2691. SSRy, which is located on the first exon of a gene encoding carotenoid cleavage dioxygenase (CCD4), was cosegregated with the Y locus in two peach F1 populations. RNA-Seq and qRT-PCR analysis revealed transcript level of CCD4 was consistent with carotenoid degradation in peach fruits. All these results suggest that CCD4 is responsible for white and yellow coloration of peach fruit flesh. In fruits of white-fleshed peach, carotenoids are synthesized but subsequently degraded into colorless compounds, leading to the formation of white color. CCD4 is likely to utilize β-carotene as the substrate in peach. Interestingly, CCD4 also controls white and yellow coloration of leaf midveins of peach. Moreover, LCYE was highly expressed in peach leaves, whereas its transcript was not detectable in fruits. This suggests the difference of carotenoid biosynthesis between peach fruits and leaves. Our study not only shows for the first time the pleiotropic effects of CCD4 gene in peach but also provides a morphological marker for easy selection of new peach cultivars with desirable white or yellow flesh colors.

The sub-cellular localisation of the potato (Solanum tuberosum L.) carotenoid biosynthetic enzymes, CrtRb2 and PSY2

Carotenoids are isoprenoids with important biological roles both for plants and animals. The yellow flesh colour of potato (Solanum tuberosum L.) tubers is a quality trait dependent on the types and levels of carotenoids that accumulate. The carotenoid biosynthetic pathway is well characterised, facilitating the successful engineering of carotenoid content in numerous crops including potato. However, a clear understanding concerning the factors regulating carotenoid accumulation and localisation in plant storage organs, such as tubers, is lacking. In the present study, the localisation of key carotenoid biosynthetic enzymes was investigated, as one of the unexplored factors that could influence the accumulation of carotenoids in potato tubers. Stable transgenic potato plants were generated by over-expressing β-CAROTENE HYDROXYLASE 2 (CrtRb2) and PHYTOENE SYNTHASE 2 (PSY2) genes, fused to red fluorescent protein (RFP). Gene expression and carotenoid levels were both significantly increased, confirming functionality of the fluorescently tagged proteins. Confocal microscopy studies revealed different sub-organellar localisations of CrtRb2-RFP and PSY2-RFP within amyloplasts. CrtRb2 was detected in small vesicular structures, inside amyloplasts, whereas PSY2 was localised in the stroma of amyloplasts. We conclude that it is important to consider the location of biosynthetic enzymes when engineering the carotenoid metabolic pathway in storage organs such as tubers.