Lower Anthocyanin Content Research Articles

Morphophysiological characterization of leaves and inflorescences of commercial mini chrysanthemum varieties

Abstract Chrysanthemum is among the oldest plants cultivated by man, being widely cultivated in Brazil. In view of its economic importance and use in breeding, the present study aims to characterize mini chrysanthemum varieties, focusing on morphological and physiological parameters. Therefore, four varieties of mini chrysanthemums, in pots, were acquired in the local market: V1 - ‘Swifty Light Pink’ (purple), V2 - ‘Diablo Time’ (red), V3 - ‘White Cherie’ (white); V4 - ‘Giovanni’ (yellow), from which they were taken leaves and inflorescences samples for measurement of height, diameter and fresh mass, as well as to quantify the total soluble sugar (TSS, %), reducing sugar (RS, %), non-reducing sugar (NRS, %), anthocyanin and chlorophyll contents. Regarding the characterization of inflorescences, it was found that ‘Diablo Time’ had the largest diameter, height and fresh weight, in these last two cases not differing from ‘Giovanni’, which had lower anthocyanin content; while the highest values of carbohydrate content were found in ‘White Cherie’. In relation to the characterization of the leaves, ‘Giovanni’ had the largest dimensions, fresh mass and chlorophyll content. Already ‘Swifty Light Pink’ stood as to the sugar contents. Thus, it is clear that there are morphophysiological differences between the chrysanthemum mini varieties, which can contribute to breeding programs.

Bok choy (Brassica rapa) grown in copper oxide nanoparticles-amended soils exhibits toxicity in a phenotype-dependent manner: Translocation, biodistribution and nutritional disturbance

The comparative toxicity of nano/bulk cupric oxide (CuO) and ionic copper (Cu) in Rosie and Green bok choy (Brassica rapa) varieties, with higher and lower anthocyanin contents, respectively, was investigated. Both phenotypes were cultivated for 70 days in natural soil amended with nano CuO (nCuO), bulk CuO (bCuO), and Cu chloride (CuCl2) at 75, 150, 300, and 600 mg Cu/kg soil. Essential elements in tissues, agronomical parameters, chlorophyll content, and Cu distribution in leaf were determined. In both varieties, nCuO treatments significantly increased Cu uptake in roots, compared with bCuO and CuCl2 (p ≤ 0.05). At all treatment concentrations, Rosie variety had more Cu than Green. More physiological impairments such as chlorophyll and leaf biomass reduction were observed in treated-Rosie varieties, compared to Green plants. The adverse effects were higher in nCuO-treated plants than their bCuO- or ionic Cu-exposed counterparts. Different distribution patterns of the translocated Cu in leaf midrib and parenchyma depended on particle size and plant phenotype, as demonstrated by two-photon microscopy. The different effects of CuO-based compounds in Rosie and Green varieties may be related to the anthocyanin content. These findings help to understand the factors involved in nanoparticles uptake and translocation to plant edible parts.

Photochemical activity in early-developmental phases of Agave angustifolia subsp. tequilana under induced global warming: Implications to temperature stress and tolerance

Agave species are a key component of the structure vegetation in the American drylands and have various anthropogenic uses. Agave angustifolia subsp. tequilana is an economically and culturally important Mexican species. Negative impacts on biodiversity are expected as a consequence of global warming; however, it has been documented that some Agave species are not affected by projected warming. Previous studies on some succulent species under induced global warming have shown a certain level of tolerance to temperature stress. We evaluated the potential temperature stress tolerance of two early developmental phases of A. angustifolia subsp. tequilana, by means of the following photochemical parameters: maximum quantum efficiency of photosystem II (Fv/Fm); effective quantum yield of PSII (ΦPSII); electron transport rate (ETR); non-photochemical quenching (NPQ); and pigment content (total chlorophyll, carotenoids and anthocyanins) in two-year-old plants and five-year-old plants under induced warming. Temperature and vapor pressure deficit (VPD) were higher in open-top chamber (OTCs) induced warming treatment than control plots, reproducing current climatic conditions. Both developmental phases showed high Fv/Fm values in both OTCs and control plots. Two-year-old plants displayed higher NPQ values than five-year-old plants under warming. The ΦPSII and ETR values were low in both warming treatments and developmental phases. Low anthocyanin content was found in both treatments and developmental phases. Independently of warming, the two-year-old plants showed higher total chlorophyll and carotenoid content values than the five-year-old plants. Despite that induced warming affected the photochemical activity of A. angustifolia subsp. tequilana, the high NPQ and pigment values indicate that this species has a high tolerance to future global warming. Our results provide novel evidence of the high physiological tolerance that could act in the early developmental phases of a key Agave species to cope the effects of global warming.

Physicochemical characterization and trait stability in a genetically diverse ex situ collection of pomegranate (Punica granatum L.) germplasm from Cyprus

Proximity to the center of origin and geographical isolation shaped a unique genetic diversity of pomegranate in Cyprus that constitutes a valuable resource for the crop. Physicochemical characters and trait stability were studied for three years in an ex situ collection of 29 pomegranate accessions from Cyprus. Accession signature traits with exceptional yearly stability were titratable acidity and the citrate/malate ratio. Overall, the Cypriot germplasm was characterized by juice of low anthocyanin content (x¯ = 20.6 mg/L) and moderate phenolic content (x¯ = 613.0 mg/L) with glucose (x¯ = 69.1 g/L) and fructose (x¯ = 74.2 g/L) as predominant sugars. Juice antioxidant capacity was associated primarily with total phenolics and less so with juice color and anthocyanin content. Total sugar content was higher in large-fruited accessions with darker juice. In most accessions the titratable acidity was low (<0.50% w/v), with citric (x¯ = 44.7%), malic (x¯ = 39.1%) and succinic (x¯ = 15.8%) being the main organic acid fractions detected. Based on the maturity index (SSC/TA), six accessions were sweet-sour or borderline sweet-sour and 23 accessions were sweet. Cluster analysis of phenotypic characteristics and genetic data revealed a core group of thirteen genetically and phenotypically close accessions constituting the Cypriot pomegranate landrace, characterized by moderate fruit weight, high juiciness, thin rind, moderately hard seeds and light-colored juice low in acidity, anthocyanins, phenolics and antioxidant capacity. The present work advances the understanding of genetic and environmental contribution to the configuration of pomegranate physicochemical fruit composition.

Light- and Temperature-Induced Expression of an R2R3-MYB Gene Regulates Anthocyanin Biosynthesis in Red-Fleshed Kiwifruit.

The R2R3 MYB genes associated with the flavonoid/anthocyanidin pathway feature two repeats, and represent the most abundant classes of MYB genes in plants; however, the physiological role and regulatory function of most R2R3 MYBs remain poorly understood in kiwifruit (Actinidia). Here, genome-wide analysis identified 155 R2R3-MYBs in the ‘Red 5′ version of the Actinidia chinensis genome. Out of 36 anthocyanin-related AccR2R3-MYBs, AcMYB10 was the most highly expressed in inner pericarp of red-fleshed kiwifruit. The expression of AcMYB10 was highly correlated with anthocyanin accumulation in natural pigmentation during fruit ripening and light-/temperature-induced pigmentation in the callus. AcMYB10 is localized in the nuclei and has transcriptional activation activity. Overexpression of AcMYB10 elevates anthocyanin accumulation in transgenic A. chinensis. In comparison, A. chinensis fruit infiltrated with virus-induced gene silencing showed delayed red coloration, lower anthocyanin content, and lower expression of AcMYB10. The transient expression experiment in Nicotiana tabacum leaves and Actinidia arguta fruit indicated the interaction of AcMYB10 with AcbHLH42 might strongly activate anthocyanin biosynthesis by activating the transcription of AcLDOX and AcF3GT. In conclusion, this study provides novel molecular information about R2R3-MYBs in kiwifruit, advances our understanding of light- and temperature-induced anthocyanin accumulation, and demonstrates the important function of AcMYB10 in the biosynthesis of anthocyanin in kiwifruit.

Mepanipyrim residues on pasteurized red must influence the volatile derived compounds from Saccharomyces cerevisiae metabolism.

The impact of mepanipyrim (Mep) and its corresponding commercial formulation (Mep Form) on Saccharomyces cerevisiae metabolites was assessed, separately, by using laboratory-scale wine fermentation assays on pasteurized red must. The presence of Mep did not alter the fermentation course. With regard to volatiles formed at the intracellular level by fermenting yeast cells, Mep residues affected mainly the acetate and ethyl ester biochemical pathways. In particular, the target acetates showed a notorious increment, >90%, in presence of commercial Mep Form at the higher dose assayed. The addition of Mep and Mep Form, at both tested levels, highly increased ethyl caprylate (between 42 and 63%) and ethyl caprate (between 36 and 60%) contents as the same as their respective fatty acid precursors. No important effects were observed on colour and non-volatile pyranoanthocyanins, probably due to the low anthocyanin content characteristic of pasteurized musts.

Effect on the Growth and Nutritional Components in Two Red Lettuces (Lactuca sativa L.) Cultivated Under UV Light in a Mini Plant Factory

Lettuce is one of the most suitable plant species to grow indoor or in a Plant Factory with Artificial lighting (PFAL) system, due to its short height and the relatively low light saturation point. Red lettuces are highly cultivated in PFALs, highly appreciated for its unique pigmentation and antioxidant activity, especially, the anthocyanin content that gives it the red color. However, red lettuces cultivated with PFAL in controlled environments face the challenge of having low anthocyanin content due of the lack of ultraviolet (UV) light that is necessary for its production. In this study, two red-lettuce cultivars ‘Annapolis’ and ‘Salanova’ were grown in a plant factory with LEDs (light-emitting diode) and UV light treatments to compare their growth trajectory and nutritional characteristics. Other characteristics such as Fresh Weight (FW) and total leaf area were measured to evaluate the influence of UV light in the lettuce growth. The nutritional quality of lettuces was assessed by measuring anthocyanins and polyphenols contents using a microplate reader and their ascorbic acid content measured via a reflectometer. Fresh Weight (FW), leaf area and leaf thickness under the conditions of this study, showed no effect (p&gt;0.05) on the plants growth with the incorporation of UV radiation. However, the incorporation of UV light increased the functional components in ‘Annapolis’ and ‘Salanova’ lettuces. The polyphenol and anthocyanins contents in both lettuce cultivars showed significant differences (p&lt;0.05). For ascorbic acid content, a significant difference was found only for ‘Annapolis’ lettuce. The incorporation of UV light can increase the functional ingredients such as polyphenols and anthocyanins without growth suppression for ‘Salanova’ cultivar. UV light increased polyphenol and anthocyanins contents in both cultivars, making them suitable cultivars for PFAL under the growth conditions used in this experiment. These results taken together can be used to improve the accumulation of functional ingredients in red lettuces without growth suppression incorporating UV light and that could be suitable for production in PFALs.

Grape juices produced from new hybrid varieties grown on Brazilian rootstocks – Bioactive compounds, organic acids and antioxidant capacity

The objective of this study was to assess the content of bioactive compounds, organic acids and antioxidant capacity of grape juices from Isabel Precoce, BRS Carmem, BRS Cora and IAC 138-22 Máximo varieties grown on the 'IAC 766’ and 'IAC 572’ rootstocks under tropical conditions in Brazil. In general, the color attributes of the 'Isabel Precoce' juice were inferior to those of the other juices due to their low anthocyanin content. In contrast, 'IAC 138-22 Máximo' juices showed the highest content of most individual anthocyanins, flavonols, trans-resveratrol and total phenolic compounds, and thus, higher antioxidant capacity. Except for 'BRS Carmem', all the juices presented higher sugar accumulation when 'IAC 766’ was used. This rootstock also contributed to the accumulation of t-resveratrol and most of individual anthocyanins in the 'IAC 138-22 Máximo' juices. However, the monomeric anthocyanin content was higher in 'BRS Carmem' juices when 'IAC 572’ rootstock was used.

Identification of Candidate HY5-Dependent and -Independent Regulators of Anthocyanin Biosynthesis in Tomato.

High quantities of anthocyanins in plants confer potential protective benefits against biotic and abiotic stressors. Studies have shown that the bZIP transcription factor HY5 plays a key role in controlling anthocyanin accumulation in response to light. However, in hy5 mutants, residual anthocyanins have been detected, indicating that other regulators exist to regulate anthocyanin biosynthesis in an HY5-independent manner. Here, we employed the CRISPR/Cas9 (clustered regularly interspersed short palindromic repeats/CRISPR-associated protein 9) system specifically to induce targeted mutagenesis of SlHY5 in the purple tomato cultivar 'Indigo Rose'. The T2 generation of tomato plants homozygous for the null allele of the SlHY5 frameshift mutated by a 1 bp insertion contained a lower anthocyanin content. Transcriptional analysis showed that most of the anthocyanin biosynthesis structural genes and several regulatory genes were down-regulated in the hy5 mutant lines. With transcriptome analyses of the various tissues from hy5 mutant lines, eight candidate transcription factors were identified that may regulate anthocyanin biosynthesis in an HY5-independent manner. These findings deepen our understanding of how light controls anthocyanin accumulation and facilitate the identification of the regulators of anthocyanin biosynthesis in an HY5-independent manner.

MdMYBL2 helps regulate cytokinin-induced anthocyanin biosynthesis in red-fleshed apple (Malus sieversii f. niedzwetzkyana) callus.

Anthocyanin biosynthesis is induced by cytokinins, and is regulated by MYB transcription factors. However, the underlying molecular mechanisms have not been fully characterised. In the present study, red-fleshed apple callus were induced from the leaves of an R6/R6 homozygous line, which was the hybrid offspring of Malus sieversii f. niedzwetzkyana and 'Fuji'. We analysed the callus anthocyanin contents in response to different cytokinin concentrations. We observed that cytokinin treatments upregulated the expression of anthocyanin structural genes MdDFR and MdUFGT and transcription factor genes MdMYB10 and MdbHLH3. Additionally, the expression of MdMYBL2, which encodes the bHLH and EAR motifs, was inhibited by cytokinin treatments. The MdMYBL2-overexpressing callus had lower anthocyanin contents than the wild-type controls. We noted that the expression levels of anthocyanin biosynthesis structural genes MdDFR and MdUFGT and transcription factor genes MdMYB10 and MdbHLH3 were strongly suppressed in the transgenic callus. Subsequent yeast two-hybrid, bimolecular fluorescence complementation, and pull-down assays indicated that MdMYBL2 interacts with MdbHLH3, which may influence the expression of anthocyanin biosynthesis-related genes. Our findings may provide new insights into how MYB transcription factors influence the cytokinin-regulated anthocyanin biosynthesis in red-fleshed apples.

Winegrapes dehydration under ozone-enriched atmosphere: Influence on berry skin phenols release, cell wall composition and mechanical properties

Gaseous ozone has been recently proposed as sanitizing agent to control mycobiota on grapes. The aim of this work was to evaluate the impact of ozone treatment during winegrapes dehydration (10 and 20% weight loss) on the content of phenolic compounds after treatment and their extractability during simulated maceration. The results showed that the ozone effect depends on the profile and content of anthocyanins and flavanols. For varieties characterized by prevalence of di-substituted anthocyanins and high flavanol contents, no significant differences were observed in phenolic compounds contents, but lower anthocyanin extractability was found. Instead, for varieties rich in anthocyanins and with a tri-substituted prevalent profile, lower anthocyanin contents were found at 20% WL, but their extractability was significantly increased. Using multivariate analysis, the extractability was correlated with skin cell wall composition and mechanical properties. Proteins, non-cellulosic glucose and total phenols contributed mainly to explain phenolic compounds extractability in withered grapes.

PlantSize Offers an Affordable, Non-destructive Method to Measure Plant Size and Color in Vitro.

Plant size, shape and color are important parameters of plants, which have traditionally been measured by destructive and time-consuming methods. Non-destructive image analysis is an increasingly popular technology to characterize plant development in time. High throughput automatic phenotyping platforms can simultaneously analyze multiple morphological and physiological parameters of hundreds or thousands of plants. Such platforms are, however, expensive and are not affordable for many laboratories. Moreover, determination of basic parameters is sufficient for most studies. Here we describe a non-invasive method, which simultaneously measures basic morphological and physiological parameters of in vitro cultured plants. Changes of plant size, shape and color is monitored by repeated photography with a commercial digital camera using neutral white background. Images are analyzed with the MatLab-based computer application PlantSize, which simultaneously calculates several parameters including rosette size, convex area, convex ratio, chlorophyll and anthocyanin contents of all plants identified on the image. Numerical data are exported in MS Excel-compatible format. Subsequent data processing provides information on growth rates, chlorophyll and anthocyanin contents. Proof-of-concept validation of the imaging technology was demonstrated by revealing small but significant differences between wild type and transgenic Arabidopsis plants overexpressing the HSFA4A transcription factor or the hsfa4a knockout mutant, subjected to different stress conditions. While HSFA4A overexpression was associated with better growth, higher chlorophyll and lower anthocyanin content in saline conditions, the knockout hsfa4a mutant showed hypersensitivity to various stresses. Morphological differences were revealed by comparing rosette size, shape and color of wild type plants with phytochrome B (phyB-9) mutant. While the technology was developed with Arabidopsis plants, it is suitable to characterize plants of other species including crops, in a simple, affordable and fast way. PlantSize is publicly available (http://www.brc.hu/pub/psize/index.html).

Physiological, phytochemicals and molecular analysis of color and scent of different landraces of Rosa damascena during flower development stages

Abstract Rosa damascena is one of important flowers for the production of aromatic compounds mainly used in perfume industry. In this research, complete sequences of gene coding geranylgeranyl diphosphate synthesis (GGPPS) involved in monoterpenes biosynthesis pathway was isolated from Rosa damascena “Kamoorˮ, and the relative expression of genes GGPPS, DXR, and CCD1 was characterized during flower developmental stages (A, B and C) in petals of four landraces of damask roses (Ghalhar, Lavasanat, Kamoor and Minab) by real-time quantitative fluorescence PCR. The overall expression of GGPPS gene was lower as compared with those of gene CCD1 and DXR. To further study, comprehensive analysis were done among physiological, molecular and phytochemical results to evaluate the relationship between main volatile compounds and colors. The output data revealed that damask roses with light colored flowers showed carotenoid accumulation and accommodation of higher carotenoid content and low anthocyanin content. Main volatile including citronellol, geraniol, neral, lianlyl acetate and dihydro citronellol acetate in flower development increase in the early stage, peaking in stage B and decreasing thereafter. These results suggest that the gene GGPPS may play role in the biosynthesis of volatile monoterpenes in R. damascena flowers, and this gene could be an important candidate genes for the regulation of secondary metabolism for Damask rose aromatic components.

Biochemical and functional characterization of AcUFGT3a, a galactosyltransferase involved in anthocyanin biosynthesis in the red-fleshed kiwifruit (Actinidia chinensis).

Much of the diversity of anthocyanin pigmentation in plant tissues is due to the action of glycosyltransferases, which attach sugar moieties to the anthocyanin aglycone. This step can increase both their solubility and stability. We investigated the pigmentation of the outer and inner pericarps of developing fruits of the red-fleshed kiwifruit Actinidia chinensis cv. 'Hongyang'. The results show that the red color of the inner pericarp is due to anthocyanin. Based on expression analyses of structural genes, AcUFGT was shown to be the key gene involved in the anthocyanin biosynthetic pathway. Expression of AcUFGT in developing fruit paralleled changes in anthocyanin concentration. Thirteen putative UFGT genes, including different transcripts, were identified in the genome of 'Hongyang'. Among these, only the expression of AcUFGT3a was found to be highly consistent with anthocyanin accumulation. Fruit infiltrated with virus-induced gene silencing showed delayed red colorations, lower anthocyanin contents and lower expressions of AcUFGT3a. At the same time, transient overexpression of AcUFGT3a in both Actinidia arguta and green apple fruit resulted in higher anthocyanin contents and deeper red coloration. In vitro biochemical assays revealed that recombinant AcUFGT3a recognized only anthocyanidins as substrate but not flavonols. Also, UDP-galactose was used preferentially as the sugar donor. These results indicate AcUFGT3a is the key enzyme regulating anthocyanin accumulation in red-fleshed kiwifruit.

Variability of quantitative and qualitative traits of coloured winter wheat

Abstract The aim of research was to analyse winter wheat of different grain colour and to compare newly bred coloured genotypes from our breeding in grain yield and technological and nutritional quality. The set of seven purple, five blue and four yellow wheats of different origin, including seven newly bred genotypes from Vígľaš-Pstruša, was evaluated in the field experiments established by randomised complete block design in two replications in Piešťany, in the vegetations 2012/13 and 2013/14. In seven wheat varieties differing in grain colours (selected after two of each colour plus control red variety Ilona) anthocyanin composition was evaluated by HPLC analysis. Significant differences were between growing years and among colour groups in most analysed traits. Blue grain newly bred K 3575 699/3 showed the highest anthocyanin content (by 33.5% higher compared to blue grain registered variety Scorpion). However, blue grain genotypes showed negative agronomic traits combined with low number and grain weight per spike and high plant height. In new purple variety PS Karkulka, declared grain yield and its quality were confirmed and the highest mineral content (Fe, Zn, Cu, Mn) was found in selected set. Purple grain newly bred PS 5711 had lower anthocyanin content (by 17.7%), but in quality it was comparable to PS Karkulka. Varieties with yellow endosperm showed the highest number and weight of grains per spike, however it was significantly lower to Ilona. The breeding goal of coloured winter wheat is still to improve the grain yield as well as additional agronomics traits.

Polyphenol metabolism in differently colored cultivars of red currant (Ribes rubrum L.) through fruit ripening.

Rare red currants colors caused by low anthocyanin content in the pink and a lack of anthocyanins in the white cultivar correlated with low ANS gene expression, enzyme activity, and increased sugar/acid ratios. Changes in the contents of polyphenols, sugars, and organic acids in berries of the three differently colored Ribes rubrum L. cultivars ('Jonkheer van Tets', 'Pink Champagne', and 'Zitavia') were determined by LC-MS and HPLC at 4 sampling times during the last month of fruit ripening. The activities of the main flavonoid enzymes, chalcone synthase/chalcone isomerase (CHS/CHI), flavanone 3-hydroxylase (FHT), and dihydroflavonol 4-reductase (DFR), and the expression of anthocyanidin synthase (ANS) were additionally measured. Despite many attempts, activities of flavonol synthase and glycosyltransferase did not show reliable results, the reason of which they could not be demonstrated in this study. The pink fruited cultivar 'Pink Champagne' showed generally lower enzyme activity than the red cultivar 'Jonkheer van Tets'. The white cultivar 'Zitavia' showed very low CHS/CHI activity and ANS expression and no FHT and DFR activities were detected. The DFR of R. rubrum L. clearly preferred dihydromyricetin as substrate although no 3',4',5'-hydroxylated anthocyanins were present. The anthocyanin content of the red cultivar slightly increased during the last three weeks of ripening and reached a maximum of 890mgkg-1 FW. Contrary to this, the pink cultivar showed low accumulation of anthocyanins; however, in the last three weeks of ripening, their content increased from 14 to 105mgkg-1 FW. Simultaneously, the content of polyphenols slightly decreased in all 3 cultivars, while the sugar/acid ratio increased. The white cultivar had no anthocyanins, but the sugar/acid ratios were the highest. In the white and pink cultivars, reduction/lack of anthocyanins was mainly compensated by increased relative concentrations of hydroxycinnamic acids and flavonols.

Influence of spray drying on water solubility index, apparent density, and anthocyanin content of pomegranate juice powder

Pomegranates, originally cultivated in Iran and a valuable medicinal and nutritional fruit, could be converted into pomegranate juice powder to be accessible in other seasons and used as a valuable ingredient in other food and pharmaceutical products. In this research, pomegranate juice was spray dried at three maltodextrin levels (25, 35 and 45% w/w) and two inlet air temperatures (124 and 143°C) and physicochemical and nutritional characteristics of the powder were surveyed. The experiments were carried out to measure drying yield, water solubility index, apparent density, color values, anthocyanin content, and morphological properties of the pomegranate juice powders. Inlet air temperature just could affect density of the powder while maltodextrin level could influence anthocyanin content of the final powder as well. Higher maltodextrin levels and temperatures lowered a* values of the powder, due to the lower anthocyanin content remained in the product at these situations. SEM analysis revealed that lower maltodextrin levels and higher inlet air temperatures resulted in smaller but smoother particles. In conclusion, pomegranate juice powders produced at 25% maltodextrin level and 124°C, with high water solubility index of 95%, high density of 0.889gcm−3, and anthocyanin content of 8mgL−1, are suitable and nutritionally-rich choices for industrial production.

New Allelic Variant Discovered at Soybean Flower Color Locus W1 Encoding Flavonoid 3′5′‐hydroxylase

A soybean line producing light purple flowers (E023‐H‐12) was developed from an ethyl methanesulfonate (EMS)‐treated population of cultivar Bay. The objective of this study was to investigate the genetic and molecular basis of flower color variation in E023‐H‐12. Genetic analysis suggested that the W1 gene encoding a flavonoid 3′5′‐hydroxylase (F3′5′H) controls light purple flower color. A single plant with purple flowers was generated in an F2 population derived from a cross between E023‐H‐12 and Clark‐w1 with white flowers, probably because of intragenic recombination of the F3′5′H gene. The allele for light purple flower was designated as w1‐lp2. The dominance relationships of the locus were W1 &gt; w1‐lp2 &gt; w1. Flower petals of E023‐H‐12 had similar expression levels of the F3′5′H gene but they had 42% less anthocyanins compared with Bay. The lower anthocyanin content may account for the light purple color of this mutant line. The nucleotide sequence of the F3′5′H gene of E023‐H‐12 had a single nucleotide polymorphism (SNP) resulting in alteration of an amino acid (H137L). A derived cleaved amplified polymorphic sequence (dCAPS) marker to discriminate the SNP co‐segregated with flower color. Thus, the amino acid substitution may be responsible for the lower anthocyanin content, and, consequently, light purple flower color.

The grapevine VviPrx31 peroxidase as a candidate gene involved in anthocyanin degradation in ripening berries under high temperature.

Anthocyanin levels decline in some red grape berry varieties ripened under high-temperature conditions, but the underlying mechanism is not yet clear. Here we studied the effects of two different temperature regimes, representing actual Sangiovese (Vitis vinifera L.) viticulture regions, on the accumulation of mRNAs and enzymes controlling berry skin anthocyanins. Potted uniform plants of Sangiovese were kept from veraison to harvest, in two plastic greenhouses with different temperature conditions. The low temperature (LT) conditions featured average and maximum daily air temperatures of 20 and 29°C, respectively, whereas the corresponding high temperature (HT) conditions were 22 and 36°C, respectively. The anthocyanin concentration at harvest was much lower in HT berries than LT berries although their profile was similar under both conditions. Under HT conditions, the biosynthesis of anthocyanins was suppressed at both the transcriptional and enzymatic levels, but peroxidase activity was higher. This suggests that the low anthocyanin content of HT berries reflects the combined impact of reduced biosynthesis and increased degradation, particularly the direct role of peroxidases in anthocyanin catabolism. Overexpression of VviPrx31 decreased anthocyanin contents in Petunia hybrida petals under heat stress condition. These data suggest that high temperature can stimulate peroxidase activity thus anthocyanin degradation in ripening grape berries.

Effect of edible coatings on eating and functional quality of Japanese plum cv. Santa Rosa

Plum (Prunus salicina L.) fruits of cv. Santa Rosa, were treated with SemperfreshTM (1:3), vegetable wax (1:5) and lac based (2:3) as an edible coating on the farm as well as after transportation to the laboratory (off-farm). Analytical determinations were made after 3, 6, 9, 12 and 15 days at 20 ± 2°C. All surface coatings, especially lac based wax were effective in inhibiting loss of moisture, ascorbic acid, total antioxidant activity and total phenols content. Lac based and SemperfreshTM displayed better efficacy in maintaining firmness followed by vegetable wax. At the end of storage period, lac based coated fruits showed higher fruit firmness (8.87 and 8.53 N) than control (6.50 and 6.30 N) in both on-farm and off-farm treatments, respectively followed by SemperfreshTM coated fruits (7.84 and 7.79 N). Maximum loss in titratable acidity (52%) was observed in control fruits whereas minimum loss was observed in on-farm treated lac based and SemperfreshTM coated fruits. The delay of the ripening process was also related to lower anthocyanin accumulation and least colour changes. After 15 days of storage, lac based coated fruits showed ∼13% lower anthocyanin content. The maximum total antioxidant activity and ascorbic acid content at end of storage were recorded in on-farm treated fruits with lac based coating (17.49 μmole Trolox/g and 3.92 mg/100 g, respectively), followed by SemperfreshTM and vegetable wax. Overall, results suggest that the surface treatments with lac based and SemperfreshTM coatings could effectively maintain the acceptability of plum fruits.