Solar UVB response of bioactives in strawberry (Fragaria × ananassa Duch. L.): a comparison of protected and open-field cultivation

Screening and classification of rosehip (Rosa canina L.) genotypes based on horticultural characteristics

BACKGROUND

During the pandemic, the interest in colorful wild small fruits increased due to their positive effects on health. Also it has become very important to offer species with high nutritional value as fresh or processed products for human consumption due to increasing world population and decreasing arable land. In this context, we characterized the horticultural characteristics of 11 rosehip genotypes grown from seeds.

RESULTS

Citric acid was determined as the main organic acid in all the genotypes investigated. The mean values of the organic acids obtained from all the genotypes were found to be as follows: citric acid (7177 mg L-1), malic acid (3669 mg L-1), tartaric acid (1834 mg L-1), oxalic acid (1258 mg L-1), carboxylic acid (631.9 mg L-1), shikimic acid (157.8 mg L-1), ascorbic acid (155 mg L-1), and acetic acid (20.9 mg L-1). Ellagic acid was the dominant phenolic compound (90.1 mg L-1 - 96.2 mg L-1) in all genotypes. The average values obtained from all genotypes for total phenolics, total flavonoids, and antioxidant activity were 37 261 mg GAE L-1, 526.2 mg quercetin L-1, and 93.6%, respectively. These characteristics had the lowest coefficients of variation, which indicated that all genotypes were similar regarding high biochemical with antioxidant effect. In addition, fruit width, fruit length, and fruit weight varied between 13.0 and 17.3 mm, 20.7 and 25.5 mm, and 1.4 and 2.7 g, respectively.

CONCLUSIONS

The genotypes were categorized according to different purposes, such as suitability for wine production, making vinegar, etc. While the pomological characteristics were strongly positively correlated among themselves, they were generally found to be negatively correlated with the phytochemical characteristics. Categorizing genotypes according to different usage purposes can improve the agricultural and industrial application of rosehip and enhance their breeding efficacy.

Post-anthesis thermal stress induces differential accumulation of bioactive compounds in field-grown barley

BACKGROUND

Barley (Hordeum vulgare L.) is a healthy grain because of its high content of dietary fibre and phenolic compounds. It faces periods of high temperature during grain filling, frequently reducing grain weight. Heat stress may also affect some of the bioactive compounds present in the grain. To produce quality grains that provide nutritional and health benefits, it is important to understand the effect of environmental stresses on the quantity and quality of bioactive compounds.

RESULTS

We have studied the effect of post-anthesis thermal stress on barley bioactive compounds and antioxidant capacity under Mediterranean field conditions during two consecutive growing seasons in four barley genotypes. Thermal stress affected grain weight and size and changed the relative composition of bioactive compounds. The relationship between heat stress and grain β-glucans and arabinoxylans content was indirect, as the resulting increases in concentrations were due to the lower grain weight under stress. Conversely, heat stress had a significant direct impact on some phenolic compounds, increasing their concentrations differentially across genotypes, which contributed to an improvement in antioxidant capacity of up to 30%.

CONCLUSION

Post-anthesis thermal stress had a significant effect on β-glucans, arabinoxylans, phenolic compound concentration and antioxidant capacity of barley grains. Final grain quality could, at least partially, be controlled in order to increase the bioactive concentrations in the barley grain, by cultivation in growing areas prone to heat stress. Late sowings or late flowering genotypes could also be considered, should a premium be implemented to compensate for lower yields. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Preharvest long-term exposure to UV-B radiation promotes fruit ripening and modifies stage-specific anthocyanin metabolism in highbush blueberry

Ultraviolet-B (UV-B) light (280-315 nm) is an important environmental signal that regulates plant development and photomorphogenesis, while also affecting the flavonoid pathway, including anthocyanin biosynthesis. Regarding the effects of UV-B radiation on fruits, the effects of a short-term or postharvest irradiation on fruit quality have been well-documented, but the effects of a long-term preharvest UV-B irradiation on fruit growth and coloration remain unclear. Thus, in this study, we investigated the effects of a long-term treatment involving an environmentally relevant UV-B dose on highbush blueberry (Vaccinium corymbosum) fruit. The preharvest UV-B treatment quickly promoted fruit growth and sugar accumulation, which is not commonly observed in other fruit tree species. The UV-B exposure also accelerated fruit ripening and coloration. The dual-luciferase assay proved that in blueberries, expression of VcUFGT encoding anthocyanin biosynthesis key enzyme, is positively and negatively regulated by VcMYBA1 and VcMYBC2, respectively. Throughout the fruit development stage, the UV-B treatment up-regulated VcMYBPA1 expression, which increased VcUFGT expression via VcMYBA1. In the green fruit stage, the UV-B treatment increased HY5 encoding UV receptor, which up-regulates VcMYBPA1 and down-regulates VcMYBC2, thereby promotes the accumulation of anthocyanins. On the other hand, excessive anthocyanin synthesis was inhibited by increased VcMYBC2 levels in mature fruits when exposed to UV-B light through HY5-independent pathway. In conclusion, anthocyanin-related MYB activators and repressor may coordinately balance the accumulation of anthocyanins in blueberry fruits, with UV-B treatments possibly influencing their effects in a stage-specific manner. The potential utility of preharvest UV-B treatments for improving blueberry fruit quality is discussed herein.

Influence of Post-Flowering Climate Conditions on Anthocyanin Profile of Strawberry Cultivars Grown from North to South Europe

The effect of cultivar and environmental variations and their interaction on anthocyanin components of strawberry were assessed for six cultivars grown in five locations from North to South of Europe in two different years. To evaluate the impact of latitude- and altitude-related factors, daily mean (Tmean), maximum (Tmax) and minimum (Tmin) temperature and global radiation accumulated for 3, 5, 10 and 15 days before fruit sampling, was analyzed. In general, fruits grown in the south were more enriched in total anthocyanin and pelargonidin-3-glucoside (pel-3-glc), the most abundant anthocyanin in strawberry. Principal component analysis (PCA) provided a separation of the growing locations within a cultivar due to latitudinal climatic differences, temporary weather changes before fruit collection and cultivation technique. PCA also depicted different patterns for anthocyanin distribution indicating a cultivar specific reaction on the environmental factors. The linear regression analysis showed that pel-3-glc was relatively less affected by these factors, while the minor anthocyanins cyanidin-3-glucoside, cyanidin-3-(6-O-malonyl)-glucoside, pelargonidin-3-rutinoside and pelargonidin-3-(6-O-malonoyl)-glucoside were sensitive to Tmax. The global radiation strongly increased cya-3-mal-glc in ‘Frida’ and pel-3-rut in ‘Frida’ and ‘Florence’. ‘Candonga’ accumulated less pel-3-glc and total anthocyanin with increased global radiation. The anthocyanin profiles of ‘Gariguette’ and ‘Clery’ were unaffected by environmental conditions.

A Review of Strawberry Photobiology and Fruit Flavonoids in Controlled Environments

Rapid technology development in controlled environment (CE) plant production has been applied to a large variety of plants. In recent years, strawberries have become a popular fruit for CE production because of their high economic and nutritional values. With the widespread use of light-emitting diode (LED) technology in the produce industry, growers can manipulate strawberry growth and development by providing specific light spectra. Manipulating light intensity and spectral composition can modify strawberry secondary metabolism and highly impact fruit quality and antioxidant properties. While the impact of visible light on secondary metabolite profiles for other greenhouse crops is well documented, more insight into the impact of different light spectra, from UV radiation to the visible light spectrum, on strawberry plants is required. This will allow growers to maximize yield and rapidly adapt to consumer preferences. In this review, a compilation of studies investigating the effect of light properties on strawberry fruit flavonoids is provided, and a comparative analysis of how light spectra influences strawberry's photobiology and secondary metabolism is presented. The effects of pre-harvest and post-harvest light treatments with UV radiation and visible light are considered. Future studies and implications for LED lighting configurations in strawberry fruit production for researchers and growers are discussed.

Plant Responses to UV Blocking Greenhouse Covering Materials: A Review

Pure polyethylene (PE) is enriched with several additives to make it a smart application material in protected cultivation, as a cover material for either greenhouses or screenhouses. When this material completely or partially absorbs ultraviolet (UV) solar radiation, then it is called UV blocking material. The current work presents a review on the effects of the UV blocking covering materials on crop growth and development. Despite the passage of several years and the evolution of the design technology of plastic greenhouse covers, UV blocking materials have not ceased to be a rather interesting technique for the protection of several vegetable and ornamental species. Much of the research on UV blocking materials focuses on their indisputable effect on reducing the activity of pests and viral-related diseases, rather than on the effects on the crop physiology itself. In the present paper, representative studies dealing with the effect of the UV blocking materials on the agronomic factors of different crops are presented and discussed. The results reveal that UV blocking materials have mainly positive effects on the different plant physiological functions, such as photosynthesis and transpiration rate, and on growth characteristics, while they might have a negative effect on the production and content of secondary compounds, as anthocyanins and total phenolics.

The Interaction between Antioxidants Content and Allergenic Potency of Different Raspberry Cultivars

Food allergies are a very serious problem among consumers. The most common food allergies involve animal products, but they can also involve fruits such as berries. We aimed to determine whether organic farming is useful for the production of high-quality and safe fruits. Three varieties of raspberries 'Laszka', 'Glen Ample' and 'Polka' from organic and conventional production (neighboring farms) were collected over the two years of the experiment. Quantitative and qualitative analysis of phenolic compounds was carried out, and the content of Bet v1 and profilin was determined. The organic raspberries contained a lower level of phenolic compounds, especially anthocyanins. Conventional fruits were characterized by a higher allergenic potency than organic ones. We found a strong link between their anthocyanin content and the allergy status of conventional raspberry fruits. Therefore, organically produced raspberries are safer for consumers.

Urinary Excretion of Anthocyanins Following Consumption of Strawberry and Red Grape Juice

The excretion of anthocyanins in urine following consumption of a mixed juice prepared from strawberry and red grape juice was investigated in a human intervention study. Unmetabolised anthocyanins, and glucuronide derivatives have been detected, with pelargonidin-3 glucoside metabolised into pelargonidin monoglucuronide and pelargonidin-3-glucoside monoglucuronide. The mass of urinary anthocyanins excreted in 24 h following consumption of the mixed juice (containing 21.93 mg of anthocyanins) was 144 nmol consisting of 106 nmol of anthocyanins derived from strawberries (0.32% of ingested dose) and 38 nmol derived from red grapes (0.22% of ingested dose). A higher proportion of delphinidin-3-glucoside was excreted in the unmetabolised form than less polar anthocyanins (at p ≤ 0.05). Excretion of anthocyanins peaked between 2 and 4 h following consumption of the juice. The proportion of the ingested anthocyanins excreted was not significantly different for strawberry and red grape anthocyanins despite the differences in the structures.

Transcriptome Analysis Reveals Complex Molecular Mechanisms Underlying UV Tolerance of Wheat ( Triticum aestivum, L.)

Plants have inherent tolerance to UV stress. However, very limited information is available about how wheat perceives and defends against UV disaster. To obtain the molecular mechanisms underlying UV tolerance of wheat, the phenotypic and transcriptomic responses of ZN168 and ZKM138 with contrasting UV tolerance were characterized. Compared with ZKM138, ZN168 showed significantly less UV damage. High-throughput sequencing revealed that UV stress inhibited the expression of genes related to photosynthesis and carbon fixation and a less degree for ZN168 than ZKM138. The distinctive performance of ZN168 is mediated by the selective expression of genes involved in multiple defense responses. Besides, metabolome analysis on grains suggested that UV radiation had a significant effect on anthocyanin accumulation. This study will enable us to exploit genes pinpointed as the targets of genetic engineering, thereby improving the UV tolerance of wheat. Furthermore, the anthocyanin-enriched wheat can be excellent resources to act as functional food.

Transcriptome profiling of genes related to light-induced anthocyanin biosynthesis in eggplant (Solanum melongena L.) before purple color becomes evident

Background

The anthocyanins are highly enriched in eggplants (Solanum melongena L.) with purple peel. However, our previous study showed that anthocyanins biosynthesis in eggplant cultivar ‘Lanshan Hexian’ was completely regulated by light and color becomes evident at most 2 days after exposure to light. In the present investigation, transcriptome study was made to explore the underlying molecular mechanisms of light-induced anthocyanin biosynthesis in eggplant (Solanum melongena L.) before color becomes evident.

Results

RNA-Seq was performed for four time points (0, 0.5, 4 and 8 h after bags removal) where concerted changes happened. A total of 32,630 genes or transcripts were obtained by transcriptome sequencing, from which 1956 differentially expressed genes (DEGs) were found. Gene Ontology analysis showed that the 1956 DEGs covered a wide range of cellular components, molecular functions and biological processes. All the DEGs were further divided into 26 clusters based on their distinct expression patterns. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis found out 24 structural anthocyanin biosynthesis genes which distributing in seven clusters. In addition, 102 transcription factors, which exhibited highly dynamic changes in response to light, were found in the seven clusters. Three photoreceptors, UV Resistance Locus 8 (UVR8), Cryptochrome 3 (CRY3) and UVR3, were identified as DEGs. The light signal transduction elements, COP1 and two SPAs, might be responsible for anthocyanin biosynthesis regulation.

Conclusion

Based on the transcriptome data, the anthocyanin biosynthesis structural genes, transcription factors, photoreceptors and light signal transduction elements were quickly screened which may act as the key regulatory factors in anthocyanin biosynthesis pathway. By comparing the transcriptome data with our previous studies, 869 genes were confirmed to participate in the light-induced anthocyanin biosynthesis. These results expand our knowledge of light-induced anthocyanin biosynthesis in plants, which allowing for fruit coloration to be improved under low-light conditions in future.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4587-z) contains supplementary material, which is available to authorized users.

Application of Targeted Metabolomics to Investigate Optimum Growing Conditions to Enhance Bioactive Content of Strawberry

A simple, sensitive, and rapid assay based on liquid chromatography coupled to tandem mass spectrometry was designed for simultaneous quantitation of secondary metabolites in order to investigate the influence of variety and agronomic conditions on the biosynthesis of bioactive compounds in strawberry. For this purpose, strawberries belonging to three varieties with different sensitivity to environmental conditions ('Camarosa', 'Festival', 'Palomar') were grown in a soilless system under multiple agronomic conditions (electrical conductivity, substrate type, and coverage). Targeted metabolomic analysis of polyphenolic compounds, combined with advanced chemometric methods based on learning machines, revealed significant differences in multiple bioactives, such as chlorogenic acid, ellagic acid rhamnoside, sanguiin H10, quercetin 3-O-glucuronide, catechin, procyanidin B2, pelargonidin 3-O-glucoside, cyanidin 3-O-glucoside, and pelargonidin 3-O-rutinoside, which play a pivotal role in organoleptic properties and beneficial healthy effects of these polyphenol-rich foods.

Genotype-by-environment effect on bioactive compounds in strawberry (Fragaria x ananassa Duch.)

BACKGROUND

The assessment of the relative contribution of genotype, environment and the genotype-by-environmental (G × E) interaction to the performance of varieties is necessary when determining adaptation capacity.

RESULTS

The influence of temperature, ultraviolet (UV)-irradiation and sunshine duration on the quality and the composition of fruits was investigated in nine strawberry cultivars grown at three different altitudes. The UV-radiation intensity affected both pH and sugar content, which were higher for most of the varieties at low altitudes, whereas total titratable acidity was less. Fruits from plants grown at low elevation generally had a higher benzoic acid derivative content. A significant correlation was found between phenylpropanoid content and UV-radiation and sunshine duration. The flavone class appeared to be affected most by the variety effect, in contrast to flavonols and ellagitannins, which were highly affected by the environment. The accumulation of a number of secondary metabolites in strawberry fruits grown in an unusual environmental condition highlighted the acclimation effects in terms of the response of plants to abiotic stress. Finally, the genetic factor only appears to be more influential for the varieties 'Sveva' and 'Marmolada' with respect to all of the parameters considered.

CONCLUSION

A 'plant environmental metabolomics' approach has been used successfully to assess the phenotypic plasticity of varieties that showed different magnitudes with respect to the relationship between environmental conditions and the accumulation of healthy compounds. © 2017 Society of Chemical Industry.

Hydrogen peroxide, nitric oxide and UV RESISTANCE LOCUS8 interact to mediate UV-B-induced anthocyanin biosynthesis in radish sprouts

The cross talk among hydrogen peroxide (H₂O₂), nitric oxide (NO) and UV RESISTANCE LOCUS8 (UVR8) in UV-B-induced anthocyanin accumulation in the hypocotyls of radish sprouts was investigated. The results showed that UV-B irradiation significantly increased the anthocyanin accumulation and the expression of UVR8, and a similar trend appeared in radish sprouts subjected to cadmium, chilling and salt stresses regardless of light source. However, these responses disappeared under dark exposure. These results suggest that abiotic stress-induced anthocyanin accumulation and UVR8 expression were light-dependent. Moreover, abiotic stresses all enhanced the production of H₂O₂ and exogenous H₂O₂ addition significantly increased the anthocyanin concentration and UVR8 transcription, while these increases were severely inhibited by addition of dimethylthiourea (DMTU, a chemical trap for H₂O₂). It seems to suggest that H₂O₂ played an important role in the anthocyanin biosynthesis. Furthermore, addition of 0.5 mM sodium nitroprusside (SNP, a NO-releasing compound) substantially induced the anthocyanin accumulation, and H₂O₂-induced anthocyanin accumulation and UVR8 expression were significantly suppressed by co-treatment with 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO, a NO scavenger), which was parallel with the expression of anthocyanin biosynthesis-related transcription factors and structural genes. All these results demonstrate that both H₂O₂ and NO are involved in UV-B-induced anthocyanin accumulation, and there is a crosstalk between them as well as a classical UVR8 pathway.

Effects of preharvest ultraviolet-C irradiation on fruit phytochemical profiles and antioxidant capacity in three strawberry (Fragaria × ananassa Duch.) cultivars

BACKGROUND

Ultraviolet-C (UV-C) has proven effective in extending shelf-life, reducing disease incidence and increasing the levels of health-promoting compounds in several crops. While most studies were conducted at the postharvest stage, our study examined the effect of preharvest UV-C application in three strawberry cultivars (Fragaria × ananassa Duch. 'Albion', 'Charlotte' and 'Seascape'). UV-C treatment was applied from the onset of flowering until the fruits reached commercial maturity on plants grown for two consecutive seasons under greenhouse conditions. The phytochemical profiles and antioxidant capacity of the fruits were assessed at harvest.

RESULTS

The ellagic acid and kaempferol-3-glucuronide contents were significantly increased only in fruits of the cultivar 'Albion' collected from UV-C-treated plants in season 1. UV-C did not consistently affect the other phenolic compounds that were measured. Based on the results of the ferric-reducing antioxidant power, oxygen radical absorbance capacity and total phenolic content assays, the antioxidant capacity of the three strawberry cultivars was not affected by UV-C. Season and cultivar had a decisive impact on these parameters.

CONCLUSION

The effect of preharvest UV-C on the levels of bioactive compounds in strawberry fruits appears to be cultivar- dependent, with season or growing conditions having a significant impact.

Acclimation to UV-B radiation and visible light in Lactuca sativa involves up-regulation of photosynthetic performance and orchestration of metabolome-wide responses

UV-B radiation is often viewed as a source of stress for higher plants. In particular, photosynthetic function has been described as a common target for UV-B impairment; yet as our understanding of UV-B photomorphogenesis increases, there are opportunities to expand the emerging paradigm of regulatory UV response. Lactuca sativa is an important dietary crop species and is often subjected to rapid sunlight exposure at field transfer. Acclimation to UV-B and visible light conditions in L. sativa was dissected using gas exchange and chlorophyll fluorescence measurements, in addition to non-destructive assessments of UV epidermal shielding (SUV ). After UV-B treatment, seedlings were subjected to wide-range metabolomic analysis using liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS). During the acclimation period, net photosynthetic rate increased in UV-treated plants, epidermal UV shielding increased in both subsets of plants transferred to the acclimatory conditions (UV+/UV- plants) and Fv /Fm declined slightly in UV+/UV- plants. Metabolomic analysis revealed that a key group of secondary compounds was up-regulated by higher light conditions, yet several of these compounds were elevated further by UV-B radiation. In conclusion, acclimation to UV-B radiation involves co-protection from the effects of visible light, and responses to UV-B radiation at a photosynthetic level may not be consistently viewed as damaging to plant development.

Light and abscisic acid independently regulated FaMYB10 in Fragaria × ananassa fruit

Light and ABA independently regulated anthocyanin biosynthesis via activation of FaMYB10 expression. FaMYB10 accelerated anthocyanin synthesis of pelargonidin 3-glucoside and cyanidin 3-glucoside during strawberry fruit ripening. Light is an integral factor in fruit ripening. Ripening in non-climacteric fruit is also effected by the plant hormone abscisic acid (ABA). However, how light and/or ABA regulate fruit ripening processes, such as strawberry color development remains elusive. Results of the present study showed light and ABA regulated strawberry fruit coloration via activation of FaMYB10 expression, an R2R3 MYB transcription factor. Light exposure increased FaMYB10 transcript levels, flavonoid pathway genes, and anthocyanin content. Exogenous ABA promoted FaMYB10 expression, and anthocyanin content, accompanied by increased ABA-responsive transcript levels and flavonoid pathway genes. ABA biosynthesis inhibitor treatment, and RNAi-mediated down-regulation of the ABA biosynthetic gene (9-cis epoxycarotenoid dioxygenase: FaNCED1), and ABA receptor (magnesium chelatase H subunit: FaCHLH/ABAR) showed inverse ABA effects. Furthermore, additive effects were observed in anthocyanin accumulation under combined light and ABA, indicating independent light and ABA signaling pathways. FaMYB10 down-regulation by Agrobacterium-mediated RNA interference (RNAi) in strawberry fruits showed decreased pelargonidin 3-glucoside and cyanidin 3-glucoside levels, accompanied by consistent flavonoid pathway gene expression levels. FaMYB10 over-expression showed opposite FaMYB10 RNAi phenotypes, particularly cyanidin 3-glucoside synthesis by FaMYB10, which was correlated with FaF3'H transcript levels. These data provided evidence that light and ABA promoted FaMYB10 expression, resulting in anthocyanin accumulation via acceleration of flavonoid pathway gene expression. Finally, our results suggested FaMYB10 serves a role as a signal transduction mediator from light and ABA perception to anthocyanin synthesis in strawberry fruit.

Nutritional and nutraceutical quality of strawberries in relation to harvest time and crop conditions

Three strawberry varieties cultivated in soilless systems were studied for their content of primary and secondary metabolites in relation to harvest time and crop conditions. The three varieties were chosen based on their sensitivity level to environmental stress: Palomar (very sensitive), Festival (sensitive), and Camarosa (resistant). Throughout the campaign, three samplings were performed: December (extra-early production), January, and March (early production). Differences among cultivars and harvest times were observed based on the contents of sugars, organic acids, phenolic compounds, and antioxidant capacity. The higher levels for total anthocyanins and flavan-3-ols were found in Camarosa and Festival strawberries, both in the January harvest. The Palomar variety showed higher total sugar/total organic acids ratio in the March harvest. The influence of cultivation practices and environmental conditions was assessed by nested ANOVA and PLS-DA. Differences in the sugar and phenolic content were observed depending upon variety and coverage type. TEAC was most influenced by the substrate type.

Phototropin 2 is involved in blue light-induced anthocyanin accumulation in Fragaria x ananassa fruits

Anthocyanins are widespread, essential secondary metabolites in higher plants during color development in certain flowers and fruits. In strawberries, anthocyanins are also key contributors to fruit antioxidant capacity and nutritional value. However, the effects of different light qualities on anthocyanin accumulation in strawberry (Fragaria x ananassa, cv. Sachinoka) fruits remain elusive. In the present study, we showed the most efficient increase in anthocyanin content occurred by blue light irradiation. Light sensing at the molecular level was investigated by isolation of two phototropin (FaPHOT1 and FaPHOT2), two cryptochrome (FaCRY1 and FaCRY2), and two phytochrome (FaPHYA and FaPHYB) homologs. Expression analysis revealed only FaPHOT2 transcripts markedly increased depending on fruit developmental stage, and a corresponding increase in anthocyanin content was detected. FaPHOT2 knockdown resulted in decreased anthocyanin content; however, overexpression increased anthocyanin content. These findings suggested blue light induced anthocyanin accumulation, and FaPHOT2 may play a role in sensing blue light, and mediating anthocyanin biosynthesis in strawberry fruits. This is the first report to find a relationship between visible light sensing, and color development in strawberry fruits.

Genetic and environmental effects on tannin composition in strawberry (Fragaria × ananassa) cultivars grown in different European locations

Strawberry cultivars grown at different locations in Europe showed genotype- and environment-dependent variation in total phenol and anthocyanin contents. This study focused on the compositional diversity of tannins from these cultivars using a high-throughput liquid chromatography-mass spectrometric (LC-MS) technique. Cultivars grown in Germany showed differences in the relative amounts of proanthocyanidins (PACs) and ellagitannins (ETs). Cultivars grown at three different European locations showed differences in their PAC/ET balance. 'Elsanta' grown in Switzerland had higher levels of ET-derived than PAC-derived signals compared to 'Elsanta' grown in Germany and Denmark. The trend to increased ET-derived signals was also noted for 'Clery' grown in Switzerland over Germany and was apparent for 'Korona' grown in Denmark over Germany. The altered ET/PAC balance was confirmed by conventional LC-MS analysis, which highlighted specific changes in composition rather than a general increase in ET components. These findings are discussed with respect to the environmental conditions at the different European locations.

In vitro antioxidant and in vivo photoprotective effect of pistachio (Pistacia vera L., variety Bronte) seed and skin extracts

Pistachio (Pistacia vera L.) nuts are a rich source of phenolic compounds, known for their high antioxidant activity, and contained not only in the seeds but also in the skin. A pistachio cultivar of high quality is typical of Bronte, Sicily, Italy. The purpose of our study was to investigate the chemical composition and antioxidant properties of two polyphenol-rich extracts from skins (TP) and decorticated seeds (SP) of Bronte pistachios, and to verify the potential use of these extracts for topical photoprotective products. Chemical analysis showed that the TP and SP extracts contain high levels of phenolic compounds, but the TP extract is about ten times richer in phenols than the SP extract, being anthocyanins the most abundant compounds found in the TP extract. Both these extracts, and especially the TP extract, possess good radical scavenger/antioxidant properties, as shown in a series of in vitro assays carried out using homogenous and non-homogenous chemical environment. Furthermore both the TP extract and, although at a lower degree, the SP extract reduce, when topically applied, UV-B-induced skin erythema in human volunteers. These findings suggest that extracts from Bronte TP and SP could be successfully employed as photoprotective ingredients in topical cosmetic and pharmaceutical formulations.

Environmental and seasonal influences on red raspberry flavour volatiles and identification of quantitative trait loci (QTL) and candidate genes

Raspberry volatiles are important for perceptions of sensory quality, mould resistance and some have nutraceutical activities. Twelve raspberry character volatiles were quantified, 11 of them in fruit from two seasons, from plants from the Glen Moy × Latham mapping population growing in both open field and under cover (polytunnels). Effects of season and environment were examined for their impact on the content of α-ionone, α-ionol, β-ionone, β-damascenone, linalool, geraniol, benzyl alcohol, (Z)-3-hexenol, acetoin, acetic and hexanoic acids, whilst raspberry ketone was measured in one season. A significant variation was observed in fruit volatiles in all progeny between seasons and method of cultivation. Quantitative trait loci were determined and mapped to six of the seven linkage groups, as were candidate genes in the volatiles pathways.

Increasing catechin and procyanindin accumulation in high-CO2-treated Fragaria vesca strawberries

This paper deals with the impact of low temperature and high CO2 levels on flavonols, proanthocyanidins, and anthocyanins, synthesized via branched pathways from common precursors, in strawberries (Fragaria vesca L.). Flavonoids were identified with Q-TOF equipment and quantified by HPLC-quadrupole. Proanthocyanins B1 and B3 accumulated in CO2-treated strawberries, whereas in untreated (air) fruit, flavonoid production was redirected toward anthocyanin accumulation with a sharp decrease in catechin and procyanidin B3 levels. Moreover, in CO2-treated fruit, mainly in those with 20% CO2, anthocyanin accumulation did not decline. Due to its antifungal activity, catechin induction in CO2-treated strawberries could explain the capacity of high CO2 treatments to reduce fungal decay. Ascorbic acid content increased in 40% CO2-treated fruits, whereas in those treated with 20% CO2 an increase in flavonol content was observed. Despite these differences, similar antioxidant capacities were found in untreated and CO2-treated Mara de Bois strawberries.

Development of colour and firmness in strawberry crops is UV light sensitive, but colour is not a good predictor of several quality parameters

BACKGROUND

Strawberry (Fragaria × ananassa Duchesne var. Elsanta) plants were grown in polytunnels covered with three polythene films that transmitted varying levels of ultraviolet (UV) light. Fruit were harvested under near-commercial conditions and quality and yield were measured. During ripening, changes in the colour parameters of individual fruit were monitored, and the accuracy of using surface colour to predict other quality parameters was determined by analysing the correlation between colour and quality parameters within UV treatments.

RESULTS

Higher exposure to UV during growth resulted in the fruit becoming darker at harvest and developing surface colour more quickly; fruit were also firmer at harvest, but shelf life was not consistently affected by the UV regime. Surface colour measurements were poorly correlated to firmness, shelf life or total phenolics, anthocyanins and ellagic acid contents.

CONCLUSION

Although surface colour of strawberry fruits was affected by the UV regime during growth, and this parameter is an important factor in consumer perception, we concluded that the surface colour at the time of harvest was, contrary to consumer expectations, a poor indicator of firmness, potential shelf life or anthocyanin content.