Effects of Different Light Wavelengths on Fruit Quality and Gene Expression of Anthocyanin Biosynthesis in Blueberry (Vaccinium corymbosm).

Different light wavelengths display diverse effects on fruit quality formation and anthocyanin biosynthesis. Blueberry is a kind of fruit rich in anthocyanin with important economic and nutritional values. This study explored the effects of different light wavelengths (white (W), red (R), blue (B) and yellow (Y)) on fruit quality and gene expression of anthocyanin biosynthesis in blueberry. We found that the B and W treatments attained the maximum values of fruit width, fruit height and fruit weight in blueberry fruits. The R treatment attained the maximum activities of superoxide dismutase (SOD) and peroxidase (POD), and the Y treatment displayed the maximum contents of ascorbic acid (AsA), glutathione (GSH) and total phenol in fruits, thus improving blueberry-fruit antioxidant capacity. Interestingly, there were differences in the solidity-acid ratio of fruit under different light-wavelength treatments. Moreover, blue light could significantly improve the expression levels of anthocyanin biosynthesis genes and anthocyanin content in fruits. Correlation and principal component analysis showed that total acid content and antioxidant enzymes were significantly negatively correlated with anthocyanin content in blueberry fruits. These results provide new insights for the application of light wavelength to improve blueberry fruit quality and anthocyanin content.

Full-length fruit transcriptomes of southern highbush (Vaccinium sp.) and rabbiteye (V. virgatum Ait.) blueberry.

BACKGROUND: Blueberries (Vaccinium sp.) are native to North America and breeding efforts to improve blueberry fruit quality are focused on improving traits such as increased firmness, enhanced flavor and greater shelf-life. Such efforts require additional genomic resources, especially in southern highbush and rabbiteye blueberries. RESULTS: We generated the first full-length fruit transcriptome for the southern highbush and rabbiteye blueberry using the cultivars, Suziblue and Powderblue, respectively. The transcriptome was generated using the Pacific Biosciences single-molecule long-read isoform sequencing platform with cDNA pooled from seven stages during fruit development and postharvest storage. Raw reads were processed through the Isoseq pipeline and full-length transcripts were mapped to the 'Draper' genome with unmapped reads collapsed using Cogent. Finally, we identified 16,299 and 15,882 non-redundant transcripts in 'Suziblue' and 'Powderblue' respectively by combining the reads mapped to Northern Highbush blueberry 'Draper' genome and Cogent analysis. In both cultivars, > 80% of sequences were longer than 1,000 nt, with the median transcript length around 1,700 nt. Functionally annotated transcripts using Blast2GO were > 92% in both 'Suziblue' and 'Powderblue' with overall equal distribution of gene ontology (GO) terms in the two cultivars. Analyses of alternative splicing events indicated that around 40% non-redundant sequences exhibited more than one isoform. Additionally, long non-coding RNAs were predicted to represent 5.6% and 7% of the transcriptomes in 'Suziblue' and 'Powderblue', respectively. Fruit ripening is regulated by several hormone-related genes and transcription factors. Among transcripts associated with phytohormone metabolism/signaling, the highest number of transcripts were related to abscisic acid (ABA) and auxin metabolism followed by those for brassinosteroid, jasmonic acid and ethylene metabolism. Among transcription factor-associated transcripts, those belonging to ripening-related APETALA2/ethylene-responsive element-binding factor (AP2/ERF), NAC (NAM, ATAF1/2 and CUC2), leucine zipper (HB-zip), basic helix-loop-helix (bHLH), MYB (v-MYB, discovered in avian myeloblastosis virus genome) and MADS-Box gene families, were abundant. Further we measured three fruit ripening quality traits and indicators [ABA, and anthocyanin concentration, and texture] during fruit development and ripening. ABA concentration increased during the initial stages of fruit ripening and then declined at the Ripe stage, whereas anthocyanin content increased during the final stages of fruit ripening in both cultivars. Fruit firmness declined during ripening in 'Powderblue'. Genes associated with the above parameters were identified using the full-length transcriptome. Transcript abundance patterns of these genes were consistent with changes in the fruit ripening and quality-related characteristics. CONCLUSIONS: A full-length, well-annotated fruit transcriptome was generated for two blueberry species commonly cultivated in the southeastern United States. The robustness of the transcriptome was verified by the identification and expression analyses of multiple fruit ripening and quality-regulating genes. The full-length transcriptome is a valuable addition to the blueberry genomic resources and will aid in further improving the annotation. It will also provide a useful resource for the investigation of molecular aspects of ripening and postharvest processes.

Metabolome and transcriptome profiling unveil the mechanisms of light-induced anthocyanin synthesis in rabbiteye blueberry (vaccinium ashei: Reade).

BACKGROUND: Blueberry is one of the most important fruit crops worldwide. Anthocyanin is an important secondary metabolites that affects the appearance and nutritive quality of blueberries. However, few studies have focused on the molecular mechanism underlying anthocyanin accumulation induced by light intensity in blueberries. RESULTS: The metabolic analysis revealed that there were 134 significantly changed metabolites in the natural light compared to the control, and flavone, flavonol, and anthocyanins were the most significantly increased. Transcriptome analysis found 6 candidate genes for the anthocyanin synthesis pathway. Quantitative reverse transcription PCR (qRT-PCR) results confirmed changes in the expression levels of genes encoding metabolites involved in the flavonoid synthesis pathways. The flavonoid metabolic flux in the light intensity-treatment increased the accumulation of delphinidin-3-O-arabinoside compared to under the shading-treatment. Furthermore, we performed qRT-PCR analysis of anthocyanin biosynthesis genes and predicted that the gene of VcF3'5'H4 may be a candidate gene for anthocyanin accumulation and is highly expressed in light intensity-treated fruit. Through the co-expression analysis of transcription factors and anthocyanin synthesis pathway genes, we found that the VcbHLH004 gene may regulate VcF3'5'H4, and then we transformed VcbHLH004 heterologously into tomato to verify its function. CONCLUSION: These results provide novel insights into light intensity regulation of blueberry anthocyanin accumulation and represent a valuable data set to guide future functional studies and blueberry breeding.

Hierarchical regulation of MYBPA1 by anthocyanin- and proanthocyanidin-related MYB proteins is conserved in Vaccinium species.

Members of the Vaccinium genus bear fruits rich in anthocyanins, a class of red-purple flavonoid pigments that provide human health benefits, although the localization and concentrations of anthocyanins differ between species: blueberry (V. corymbosum) has white flesh, while bilberry (V. myrtillus) has red flesh. Comparative transcriptomics between blueberry and bilberry revealed that MYBPA1.1 and MYBA1 strongly correlated with the presence of anthocyanins, but were absent or weakly expressed in blueberry flesh. MYBPA1.1 had a biphasic expression profile, correlating with both proanthocyanidin biosynthesis early during fruit development and anthocyanin biosynthesis during berry ripening. MYBPA1.1 was unable to induce anthocyanin or proanthocyanidin accumulation in Nicotiana benthamiana, but activated promoters of flavonoid biosynthesis genes. The MYBPA1.1 promoter is directly activated by MYBA1 and MYBPA2 proteins, which regulate anthocyanins and proanthocyanidins, respectively. Our findings suggest that the lack of VcMYBA1 expression in blueberry flesh results in an absence of VcMYBPA1.1 expression, which are both required for anthocyanin regulation. In contrast, VmMYBA1 is well expressed in bilberry flesh, up-regulating VmMYBPA1.1, allowing coordinated regulation of flavonoid biosynthesis genes and anthocyanin accumulation. The hierarchal model described here for Vaccinium may also occur in a wider group of plants as a means to co-regulate different branches of the flavonoid pathway.

Effects of high hydrostatic pressure and thermal processing on anthocyanin content, polyphenol oxidase and ß-glucosidase activities, color, and antioxidant activities of blueberry (Vaccinium Spp.) puree.

Thermal processing (TP) and high hydrostatic pressure (HHP) are two important puree processing methods. In this study, the polyphenol oxidase (PPO) and ß-glucosidase activities, chromatic values, peroxide radical scavenging capacities (PSCs), cellular antioxidant activities (CAAs), and anthocyanin profiles were evaluated in blueberry puree following TP and HHP treatments. Nine anthocyanins were identified and cyanidin glycosides were the most abundant compounds in the blueberry puree sample. Petunidin-3-O-arabinoside, malvidin-3-O-galactoside, and malvidin-3-O-glucoside concentrations increased at temperatures of 70-90 °C (TP) and a pressure of 300 MPa (HHP). The highest total anthocyanin concentration (503.5 µg/mL) and PSC (13.45 µg VCE/mL) were observed following the TP (90 °C) treatment. Furthermore, a positive correlation was observed between the anthocyanin content and PSC (R2 = 0.655, P < 0.05). Finally, HHP treatment resulted in better puree color retention than TP treatment. The results of this study could provide valuable information for optimizing the processing methods for anthocyanin-rich products.

Immobilization of Andean berry (Vaccinium meridionale) polyphenols on nanocellulose isolated from banana residues: A natural food additive with antioxidant properties.

Nanocellulose obtained from banana rachis (NCBR) was loaded (through simple impregnation) with a polyphenolic-rich extract (PRE) of Andean berries (Vaccinium meridionale). The adsorption/desorption of polyphenols onto NCBR and the thermal stability and antioxidant activity of the polyphenolic-NCBR nanocomplex (NCX) was studied. Thermodynamic properties (ΔH°ads, ΔS°ads and ΔG°ads) showed that polyphenols interact with NCBR by physisorption through a spontaneous and exothermic process. The NCX kept the original color of PRE (magenta) and released polyphenols in aqueous medium (80% of phenolic compounds in the first hour and 50% of anthocyanins in the first few minutes). The NCX showed high antioxidant activity, as evidenced by traditional assays, and inhibited the peroxyl radicals mediated oxidation of a tryptophan-containing peptide. Additionally, NCX inhibited lipid peroxidation in an emulsified system of Sacha inchi oil exposed to accelerated oxidative conditions. In conclusion, the NCX showed good properties as an antioxidant with potential use as a food additive.

Binding of peanut allergen Ara h 2 with Vaccinium fruit polyphenols.

The potential for 42 different polyphenols found in Vaccinium fruits to bind to peanut allergen Ara h 2 and inhibit IgE binding epitopes was investigated using cheminformatics techniques. Out of 12 predicted binders, delphinidin-3-glucoside, cyanidin-3-glucoside, procyanidin C1, and chlorogenic acid were further evaluated in vitro. Circular dichroism, UV-Vis spectroscopy, and immunoblotting determined their capacity to (i) bind to Ara h 2, (ii) induce protein secondary structural changes, and (iii) inhibit IgE binding epitopes. UV-Vis spectroscopy clearly indicated that procyanidin C1 and chlorogenic acid interacted with Ara h 2, and circular dichroism results suggested that interactions with these polyphenols resulted in changes to Ara h 2 secondary structures. Immunoblotting showed that procyanidin C1 and chlorogenic acid bound to Ara h 2 significantly decreased the IgE binding capacity by 37% and 50%, respectively. These results suggest that certain polyphenols can inhibit IgE recognition of Ara h 2 by obstructing linear IgE epitopes.

A geochemical perspective on the natural abundance and predominant sources of trace elements in cranberries (Vaccinium oxycoccus) from remote bogs in the Boreal region of northern Alberta, Canada.

Trace elements in native cranberry (Vaccinium oxycoccus) were compared with the underlying Sphagnum moss on which it grows, from two remote ombrotrophic (rain-fed) peat bogs in northern Alberta, Canada. The purpose of the comparison was to distinguish between dust inputs to the berries versus plant uptake from the substrate, and to determine the natural abundance of trace elements in native berries. Using Al as an indicator of the abundance of soil-derived mineral particles, the abundance of dust on the surface of the berries is 20 to 29× lower than that of the substrate (moss). Other lithophile elements (V, Cr, Co, Ga, Li and Y) show similar differences between moss and berry. The concentrations of Rb and Ba in berries were similar to moss and Sr within a factor of 3 to 4×, probably reflecting passive uptake of these lithophile elements by the plants, even though they have no known physiological function. Of the micronutrients examined (Mn, Fe, Ni, Cu, Zn and Mo), Cu and Mn were more abundant in berries than moss, Ni and Zn yielded similar concentrations in both whereas Fe followed by Mo showed the greatest concentration difference. For these micronutrients, uptake by the plants through their roots via the substrate (moss and peat) outweighs contributions from atmospheric dusts. In respect to potentially toxic "heavy metals", Pb concentrations in the moss (BMW, 89 ±â€¯7.3 µg/kg; CMW, 93 ±â€¯27 µg/kg) are below the natural, "background" values reported for ancient layers of Swiss peat from the mid-Holocene (>6000 years old). The Pb concentrations in the berries, however, are 19 to 47× lower than in the underlying moss indicating that Pb in the berries, like Al, is exclusively supplied by dust. Cadmium in the berries is at or above the level found in moss due to active uptake by the plants from the substrate, most likely because of the chemical similarity of this element to Zn. Silver, Sb and Tl in the berries were

Bioaccessibility during In Vitro Digestion and Antiproliferative Effect of Bioactive Compounds from Andean Berry ( Vaccinium meridionale Swartz) Juice.

Berry consumption is associated with colorectal-cancer chemoprevention, but digestive conditions can affect this property. The bioaccessibility and apparent permeability coefficients of bioactive compounds from Andean Berry Juice (ABJ) after in vitro gastrointestinal digestion and colonic fermentation were analyzed. The antiproliferative effect of the fermented nondigestible fraction was evaluated against SW480 colon-adenocarcinoma cells. Gallic acid displayed the highest bioaccessibility in the mouth, stomach, small intestine, and colon. However, chlorogenic acid exhibited the highest apparent permeability coefficients (up to 1.98 × 10-4 cm/s). The colonic-fermentation fraction showed an increase of ≥50% antiproliferative activity against SW480 cells (19.32%, v/v), equivalent to those of gallic acid (13.04 µg/g), chlorogenic acid (7.07 µg/g), caffeic acid (0.40 µg/g), ellagic acid (7.32 µg/g), rutin (6.50 µg/g), raffinose (0.14 mg/g), stachyose (0.70 mg/g), and xylose (9.41 mg/g). Bioactive compounds from ABJ are bioaccessible through the gastrointestinal tract and colon fermentation, resulting in antiproliferative activity.

Nitrogen-source preference in blueberry (Vaccinium sp.): Enhanced shoot nitrogen assimilation in response to direct supply of nitrate.

Blueberry (Vaccinium sp.) is thought to display a preference for the ammonium (NH4+) form over the nitrate (NO3-) form of inorganic nitrogen (N). This N-source preference has been associated with a generally low capacity to assimilate the NO3- form of N, especially within the shoot tissues. Nitrate assimilation is mediated by nitrate reductase (NR), a rate limiting enzyme that converts NO3- to nitrite (NO2-). We investigated potential limitations of NO3- assimilation in two blueberry species, rabbiteye (Vaccinium ashei) and southern highbush (Vaccinium corymbosum) by supplying NO3- to the roots, leaf surface, or through the cut stem. Both species displayed relatively low but similar root uptake rates for both forms of inorganic N. Nitrate uptake through the roots transiently increased NR activity by up to 3.3-fold and root NR gene expression by up to 4-fold. However, supplying NO3- to the roots did not increase its transport in the xylem, nor did it increase NR activity in the leaves, indicating that the acquired N was largely assimilated or stored within the roots. Foliar application of NO3- increased leaf NR activity by up to 3.5-fold, but did not alter NO3- metabolism-related gene expression, suggesting that blueberries are capable of post translational regulation of NR activity in the shoots. Additionally, supplying NO3- to the cut ends of stems resulted in around a 5-fold increase in NR activity, a 10-fold increase in NR transcript accumulation, and up to a 195-fold increase in transcript accumulation of NITRITE REDUCTASE (NiR1) which codes for the enzyme catalyzing the conversion of NO2- to NH4+. These data indicate that blueberry shoots are capable of assimilating NO3- when it is directly supplied to these tissues. Together, these data suggest that limitations in the uptake and translocation of NO3- to the shoots may limit overall NO3- assimilation capacity in blueberry.

Polyphenol profile and antioxidant activity of the fruit and leaf of Vaccinium glaucoalbum from the Tibetan Himalayas.

Vaccinium glaucoalbum, a perennial evergreen shrub, is naturally distributed in high-altitude areas. In this study, the composition and content of polyphenolic compounds in the fruit and leaf of V. glaucoalbum were characterized. In total, 24 chemical compounds were detected and identified by HPLC-DAD and HPLC-ESI-MS2. Among all the compounds determined, 15 were anthocyanins and detected in fruit, 5 were flavonols and monitored in leaf, and 4 were chlorogenic acids and found in both fruit and leaf. The total anthocyanin content (TAC) of fruit (682mg/100gFW) was the highest among wild Vaccinium berries in China which have been investigated for now, and the total flavonol content of leaf was 2764mg/100gFW. The antioxidant activity of both fruit and leaf was assessed by DPPH and FRAP assays. Given its high TAC and strong antioxidant activity, the fruit of V. glaucoalbum has great potential in functional food.

Metabolic and molecular analyses of white mutant Vaccinium berries show down-regulation of MYBPA1-type R2R3 MYB regulatory factor.

MAIN CONCLUSION: MYBPA1-type R2R3 MYB transcription factor shows down-regulation in white mutant berries of Vaccinium uliginosum deficient in anthocyanins but not proanthocyanidins suggesting a role in the regulation of anthocyanin biosynthesis. Berries of the genus Vaccinium are among the best natural sources of flavonoids. In this study, the expression of structural and regulatory flavonoid biosynthetic genes and the accumulation of flavonoids in white mutant and blue-colored wild-type bog bilberry (V. uliginosum) fruits were measured at different stages of berry development. In contrast to high contents of anthocyanins in ripe blue-colored berries, only traces were detected by HPLC-ESI-MS in ripe white mutant berries. However, similar profile and high levels of flavonol glycosides and proanthocyanidins were quantified in both ripe white and ripe wild-type berries. Analysis with qRT-PCR showed strong down-regulation of structural genes chalcone synthase (VuCHS), dihydroflavonol 4-reductase (VuDFR) and anthocyanidin synthase (VuANS) as well as MYBPA1-type transcription factor VuMYBPA1 in white berries during ripening compared to wild-type berries. The profiles of transcript accumulation of chalcone isomerase (VuCHI), anthocyanidin reductase (VuANR), leucoanthocyanidin reductase (VuLAR) and flavonoid 3'5' hydroxylase (VuF3'5'H) were more similar between the white and the wild-type berries during fruit development, while expression of UDP-glucose: flavonoid 3-O-glucosyltransferase (VuUFGT) showed similar trend but fourfold lower level in white mutant. VuMYBPA1, the R2R3 MYB family member, is a homologue of VmMYB2 of V. myrtillus and VcMYBPA1 of V. corymbosum and belongs to MYBPA1-type MYB family which members are shown in some species to be related with proanthocyanidin biosynthesis in fruits. Our results combined with earlier data of the role of VmMYB2 in white mutant berries of V. myrtillus suggest that the regulation of anthocyanin biosynthesis in Vaccinium species could differ from other species studied.

Hydroquinone analog 4-[(Tetrahydro-2H-pyran-2­yl) oxy] phenol induces C26 colon cancer cell apoptosis and inhibits tumor growth in vivo.

The 4[(Tetrahydro­2H­pyran­2­yl) oxy] phenol (XG­d) hydroquinone analog, is found in Vaccinium vitis­idaea  L. Although it is known for its antioxidant properties and high level of safety, its antitumor activity remains to be elucidated. In the present study, the anticancer effect of XG­d was determined in vitro and in vivo. The cytotoxicity of XG­d against C26 murine colon carcinoma cells was found to occur in a time­ and concentration­dependent manner, whereas little effect was observed in the two normal cell lines (HK­2 and L02) investigated. Oral administration of XG­d (100 mg/kg) had effects on the tumor growth of tumor­bearing mice. Furthermore, marked apoptosis was observed using Hoechst 33258 staining and flow cytometric analysis with annexin V/propidium iodide double staining. XG­d also downregulated the expression of B­cell lymphoma 2 (Bcl­2), increased the expression levels of Bcl­2­associated X protein and activated caspase­9, caspase­3 and poly(adenosine diphosphate­ribose) polymerase. The present study demonstrated for the first time, to the best of our knowledge, that XG­d inhibited cancer cell growth via the induction of apoptosis and was also able to inhibit tumor growth in vivo. These results demonstrated that XG­d may be used as a potential natural agent for cancer therapy with low toxicity.

Protective effect of Vaccinium myrtillus extract against UVA- and UVB-induced damage in a human keratinocyte cell line (HaCaT cells).

Recently, the field of skin protection have shown a considerable interest in the use of botanicals. Vaccinium myrtillus contains several polyphenols and anthocyanins with multiple pharmacological properties. The purpose of our study was to examine whether a water-soluble V. myrtillus extract (dry matter 12.4%; total polyphenols 339.3mg/100 g fw; total anthocyanins 297.4 mg/100 g fw) was able to reduce UVA- and UVB-induced damage using a human keratinocyte cell line (HaCaT). HaCaT cells were pretreated for 1h with extract in a serum-free medium and then irradiated with UVA (8-40 J/cm(2)) and UVB (0.008-0.72 J/cm(2)) rays. All experiments were performed 24h after the end of irradiation, except for oxidative stress tests. The extract was able to reduce the UVB-induced cytotoxicity and genotoxicity (studied by comet and micronucleous assays) at lower doses. V. myrtillus extract reduced lipid peroxidation UVB-induced, but had no effect against the ROS UVB-produced. With UVA-induced damage V. myrtillus reduced genotoxicity as well as the unbalance of redox intracellular status. Moreover our extract reduced the UVA-induced apoptosis, but had no effect against the UVB one. V. myrtillus extract showed its free radical scavenging properties reducing oxidative stress and apoptotic markers, especially in UVA-irradiated cells.

Berry antioxidants: small fruits providing large benefits.

Small berry fruits are consumed because of their attractive colour and special taste, and are considered one of the richest sources of natural antioxidants. Their consumption has been linked to the prevention of some chronic and degenerative diseases. The term 'berry fruits' encompasses the so-called 'soft fruits', primarily strawberry, currants, gooseberry, blackberry, raspberry, blueberry and cranberry. The objective of this review is to highlight the nutraceutical value of berries and to summarize the factors affecting berry fruit antioxidants. Particular attention is given to postharvest and processing operation factors that may affect fruit phytochemical content. The structure-antioxidant relationships for phenolic compounds - the main group of antioxidants in this fruit group - are presented and major areas for future research are identified.

Metabolite profiling of polyphenols in Vaccinium berries and determination of their chemopreventive properties.

A detailed investigation on the chemical composition and chemopreventive activity of Vaccinium floribundum Kunth berries was carried out in comparison with Vaccinium myrtillus L. Berry polyphenols were extracted by using two sequential dynamic maceration steps, which enabled to maximize the yields of secondary metabolites. In particular, phenolic acids and flavonols were extracted from berries using ethyl acetate (EtOAc), whereas anthocyanins were extracted from the residue with 0.6M HCl in methanol (MeOH). The analysis of secondary metabolites in berry extracts was performed by means of two specific HPLC methods. Phenolic acids and flavonols were analyzed on an Ascentis C18 column (250mm×4.6mm I.D., 5µm), with a gradient mobile phase composed of 0.1M HCOOH in H2O and ACN. Anthocyanin analysis was carried out on a Zorbax SB-C18 column (150mm×4.6mm I.D., 5µm), with a gradient mobile phase composed of H2O-HCOOH (9:1, v/v) and MeOH-H2O-HCOOH (5:4:1, v/v/v). Detection was performed by UV/DAD, MS and MS(2). The polyphenol composition of V. floribundum and V. myrtillus was studied in detail. The samples of V. floribundum analyzed in this study had a much higher content of both phenolic acids and flavonols in comparison with V. myrtillus (mean value 41.6±10.2 and 13.7±0.2mg/100g FW, respectively), while V. myrtillus showed a higher amount of anthocyanins if compared with V. floribundum (568.8±8.8 and mean value 376.2±49.9mg/100gFW, respectively). The extracts gave negative results in antimutagenic assays against carcinogens 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) and 4-nitroquinoline-1-oxide (4-NQO), while they performed similarly in both ABTS(+) and DPPH antioxidant assays.

Relationship between polyphenol content and anti-influenza viral effects of berries.

BACKGROUND: Berries are known to have many kinds of biological activities. We focused on their antiviral effect, which has not yet been well evaluated. RESULTS: We compared the anti-influenza viral effects of berries belonging to the genus Vaccinium - 35 species of blueberry (Vaccinium cyanococcus), the Natsuhaze (Vaccinium oldhamii), bilberry (Vaccinium myrtillus) and cranberry (Vaccinium oxycoccos)- with those belonging to the genus Ribes, i.e. blackcurrant (Ribes nigrum). Only Elliott and Legacy among Northern Highbush varieties but many Rabbiteye varieties such as Austin, Baldwin, Brightblue, Festival, T-100 and Tifblue showed anti-influenza viral activity. Natsuhaze, bilberry, cranberry and blackcurrant had high antiviral effects. A relationship was observed between the antiviral effect and total polyphenol content. CONCLUSIONS: Antiviral effects were found to differ markedly between berry species. Rabbiteye varieties tended to have higher antiviral effects than Northern, Southern and Half Highbush blueberry varieties. We also found that Natsuhaze, which has recently been harvested in Japan as a potential functional food, had an antiviral effect comparable to that of bilberry, cranberry and blackcurrant. There was a positive relationship between antiviral activity and polyphenol content, indicating the possibility that polyphenol is one of the key factors in the antiviral effects of berries.

A C-repeat binding factor transcriptional activator (CBF/DREB1) from European bilberry (Vaccinium myrtillus) induces freezing tolerance when expressed in Arabidopsis thaliana.

Freezing stress affects all plants from temperate zones to the poles. Global climate change means such freezing events are becoming less predictable. This in turn reduces the ability of plants to predict the approaching low temperatures and cold acclimate. This has consequences for crop yields and distribution of wild plant species. C-repeat binding factors (CBFs) are transcription factors previously shown to play a vital role in the acclimation process of Arabidopsis thaliana, controlling the expression of hundreds of genes whose products are necessary for freezing tolerance. Work in other plant species cements CBFs as key determinants in the trait of freezing tolerance in higher plants. To test the function of CBFs from highly freezing tolerant plants species we cloned and sequenced CBF transcription factors from three Vaccinium species (Vaccinium myrtillus, Vaccinium uliginosum and Vaccinium vitis-idaea) which we collected in the Arctic. We tested the activity of CBF transcription factors from the three Vaccinium species by producing transgenic Arabidopsis lines overexpressing them. Only the Vaccinium myrtillus CBF was able to substantially activate COR (CBF-target) gene expression in the absence of cold. Correspondingly, only the lines expressing the Vaccinium myrtillus CBF were constitutively freezing tolerant. The basis for the differences in potency of the three Vaccinium CBFs was tested by observing cellular localisation and protein levels. All three CBFs were correctly targeted to the nucleus, but Vaccinium uliginosum CBF appeared to be relatively unstable. The reasons for lack of potency for Vaccinium vitis-idaea CBF were not due to stability or targeting, and we speculate that this was due to altered transcription factor function.

Pollen dispersal and fruit production in Vaccinium oxycoccos and comparison with its sympatric congener V. uliginosum.

Investigating plant-pollinator interactions and pollen dispersal are particularly relevant for understanding processes ensuring long-term viability of fragmented plant populations. Pollen dispersal patterns may vary strongly, even between similar congeneric species, depending on the mating system, pollinator assemblages and floral traits. We investigated pollen dispersal and fruit production in a population of Vaccinium oxycoccos, an insect-pollinated shrub, and compared the pollen dispersal pattern with a co-flowering, sympatric congener, V. uliginosum. We examined whether they share pollinators (through interspecific fluorescent dye transfers) and may differently attract pollinators, by comparing their floral colour as perceived by insects. Fluorescent dyes were mainly dispersed over short distances (80% within 40.4 m (max. 94.5 m) for V. oxycoccos and 3.0 m (max. 141.3 m) for V. uliginosum). Dye dispersal in V. oxycoccos was not significantly affected by plant area, floral display or the proximity to V. uliginosum plants. Interspecific dye transfers were observed, indicating pollinator sharing. The significantly lower dye deposition on V. oxycoccos stigmas suggests lower visitation rates by pollinators, despite higher flower density and local abundance. The spectral reflectance analysis indicates that bees are unlikely to be able to discriminate between the two species based on floral colour alone. Fruit production increased with increasing floral display, but was not affected by proximity to V. uliginosum plants. Our study highlights that fragmented populations of V. oxycoccos, when sympatric with co-flowering V. uliginosum, might incur increased competition for the shared pollinators in the case of pollination disruption, which might then reduce outcrossed seed set.

Long-term structural canopy changes sustain net photosynthesis per ground area in high arctic Vaccinium uliginosum exposed to changes in near-ambient UV-B levels.

Full recovery of the ozone layer is not expected for several decades and consequently, the incoming level of solar ultraviolet-B (UV-B) will only slowly be reduced. Therefore to investigate the structural and photosynthetic responses to changes in solar UV-B we conducted a 5-year UV-B exclusion study in high arctic Greenland. During the growing season, the gas exchange (H2O and CO2) and chlorophyll-a fluorescence were measured in Vaccinium uliginosum. The leaf dry weight, carbon, nitrogen, stable carbon isotope ratio, chlorophyll and carotenoid content were determined from a late season harvest. The net photosynthesis per leaf area was on average 22% higher in 61% reduced UV-B treatment across the season, but per ground area photosynthesis was unchanged. The leaf level increase in photosynthesis was accompanied by increased leaf nitrogen, higher stomatal conductance and F(v)/F(m). There was no change in total leaf biomass, but reduction in total leaf area caused a pronounced reduction of specific leaf area and leaf area index in reduced UV-B. This demonstrates the structural changes to counterbalance the reduced plant carbon uptake seen per leaf area in ambient UV-B as the resulting plant carbon uptake per ground area was not affected. Thus, our understanding of long-term responses to UV-B reduction must take into account both leaf level processes as well as structural changes to understand the apparent robustness of plant carbon uptake per ground area. In this perspective, V. uliginosum seems able to adjust plant carbon uptake to the present amount of solar UV-B radiation in the High Arctic.