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An electrochemical study of lyophilized blueberry (Vaccinium corymbosum L.) and raspberry (Rubus idaeus L.) fruits was carried out using microparticulate deposits from ethanolic extracts of fruits in contact with different aqueous electrolytes. This voltammetry is dominated by the oxidation of anthocyanins. It was hypothesized that under conditions of electrochemical generation of reactive oxygen species (ROS), new anthocyanin-derived species with high antioxidant capacity are formed over a wide pH range. In the case of ROS-activated anthocyanins, electrochemical oxidation is associated with loss of sugar moieties. Experimental voltammetric and scanning electrochemical microscopy (SECM) imaging data consistent with this hypothesis are presented.

This article emphasizes the crucial importance of yeast Meyerozyma guilliermondii (Patent CECT13190) as a biological control agent (BCA) in eliciting defensive responses in vine plants, and is supported by comprehensive physiological, proteomic, and transcriptomic analyses. The results demonstrate that the BCA M. guilliermondii can induce enhanced defensive responses, as reflected in the regulation of key proteins. Notably, the upregulated expression of calmodulin and pathogenesis-related protein 10 (PR-10) are indicative of a complex interplay between calcium signalling, salicylic acid accumulation, and the elicitation of plant defence responses against pathogens. Furthermore, changes in microtubule dynamics and proteins related to protein synthesis and folding are observed, confirming the elicitation of defence responses. The correspondence between proteomic and transcriptomic analyses for genes codifying pathogenesis-related proteins, such as Vcgns1, VviTL1, and Vcchit1b, reinforces the empirical robustness of our findings. Collectively, our research explores the modulation of plant defences by the BCA, opening promising avenues for innovative agricultural strategies that enhance crop resilience and productivity.

Blueberries (Vaccinium corymbosum L.) are becoming increasingly popular for their nutritional and health benefits, and their economic value is therefore increasing. The loss of quality that can occur due to softening and fungal attack is an important consideration when marketing blueberries. Despite the added value of blueberries, no studies have been carried out on how the fruit arrives at the outlets just before purchase by the consumer in terms of firmness, physico-chemical parameters, phenolic compounds, and fungal growth. The aim of this work has been, therefore, to investigate possible differences in quality parameters between blueberries purchased from ten different outlets, regardless of the supplier. The results showed that all the samples were of acceptable quality, although they all had a low maturity index at the point of sale. None of the samples studied showed clear signs of fungal decay at the time of purchase, although we were able to grow and identify some pathogen specimens after cultivation. In terms of total phenolic and anthocyanin content, as well as antioxidant activity, all the samples showed low values, possibly due to their postharvest storage, but they were within the expected range for this fruit. On the other hand, differences in the measured parameters were observed between samples of the same cultivar while no differences were found between conventionally and organically grown blueberries. This suggests that preharvest (such as edaphoclimatic conditions, agricultural practices, and cultivars) and postharvest factors (such as treatments used, storage, and transport temperatures) could influence the berry quality when they reach the consumer.

Los arándanos son frutos frescos blandos, que están ganando popularidad por sus propiedades farmacológicas y bioquímicas y, por tanto, su valor económico está aumentando. Esta tendencia se ha traducido en un aumento del 52% de la producción mundial en los últimos años. El creciente interés por los frutos rojos se debe a su popularización como "superalimento", debido a su elevada actividad antioxidante in vitro y a su abundancia en compuestos fenólicos como los flavonoides y los ácidos fenólicos. Se caracterizan por su alto contenido en vitamina C y, dentro de los compuestos fenólicos, entre los que se encuentran tanto flavonoides como no flavonoides, las antocianinas son las más abundantes con un 60% del total de fenoles en los arándanos maduros. La aplicación de tratamientos cortos con altos niveles de CO2 es efectiva manteniendo la calidad de diferentes frutos durante su conservación a bajas temperaturas, sin embargo, hasta el momento no se conoce su efecto en arándanos. El objetivo principal de este trabajo ha sido aplicar altos niveles de CO2 (15-20%) durante 3 días a 1ºC en arándanos cosechados en junio y septiembre, con el fin de estudiar su efecto durante la postcosecha a bajas temperaturas. Para ello se han analizado diferentes parámetros fisicoquímicos de calidad, así como el efecto de los tratamientos gaseosos en la textura y el contenido de fenoles y antocianos totales de los frutos.

Most of the waste aher harvest in strawberries (Fragaria vesca) is dueto the rapid senescence-related deterioration at ambient temperature linked toa loss of texture. While low temperatures can delay the senescence process, fruit quality is negativety impacted by loss of cell structure. Short-term high CO2 treatment helps strawberries improve cell water retention and to reduce softening during cold storage. Since texture at the time of consumption is crucial to achieve desirable fruit quality and reduce waste, it is of importance to understand the molecular mechanism in response to the temperature shifts from cold storage at 20ºc. The aim of the present work was to determine in CO2-treated strawberries which molecular mechanisms participate in an improved fruit texture upon trarnsfer to 20ºC and explore the protective processes against senescence-related deterioratlon. To achieve this, we conducted RNAseq analysis, constructing a weighted co-expression network analysis (WGCNA) to identify key genes related to resistance to softening and cell wall disassembly. Strawberries with contrasting firmness values and cold storage conditions were used. Fruit pretreated for 2 days with 18% CO2 + 18% O2 then air ventilated for another 5 days at 1ºC and there after transferred at 20ºC for 1 day were C02-cold stored (CCS). Fruit stored in a ir for 7 days at 1ºC and then transferred at 20ºC for 1 day were air-cold stored (ACS). Non-cold stored placed directly a 20ºC for 2 days (NCS) and fruit inmediately after harvest (AH) as the control, were also analyzed. The transcriptome data of firmer CO2-treated strawberries revealed a notable expression of genes required for the maintenance of cell water status, the preservation of cell wall elasticity (specificalty through the stabilization of xyloglucans), and improved integrity of the middle lamella (associated with the down-regulation of genes encoding rhamnogalacturonate lyase, and pectate lyase). Responsive responses to cold-induced

Plants are often subjected to several environmental constraints in the field, often simultaneously, which significantly affect their productivity. Among these constraints, water deficit and heat stress are the main constraints limiting plant yield in the arid regions of the Mediterranean basin. Both of these abiotic factors are exacerbated by climate change. Fodder legumes provide a rich resource of plant nutrition to human diets, and are vital for food security and sustainable cropping. Numerous biochemical, molecular, and physiological responses are evoked by drought and heat stresses, influencing the fodder crop yield and nutritional value. When plants are water stressed, they are unable to maintain good growth and produce high yields. Drought also reduces the protein content of the plants, which can lead to a decrease in forage quality. Heat can negatively affect the productivity of forage legumes. High temperatures can cause heat stress which can lead to decreased photosynthesis and reduced productivity. In addition, high temperatures can result in decreased forage quality and increased nutrient losses. Exposure to combined water stress and heat can reduce the protein, fiber and mineral content of forage legumes and can also reduce their digestibility. This review summarizes the current status of the effects of drought and heat stresses on forage crops productivity and fodder quality.

[ES] Introducción: La difusión de noticias falsas relacionadas con la nutrición muestra la necesidad de proporcionar al público general información validada sobre alimentación y salud, induciendo a llevar hábitos dietéticos saludables. Objetivo: Evaluar si la asistencia a clubs de lectura dedicados a libros de divulgación científica es una estrategia útil para mejorar el conocimiento nutricional entre la población. Metodología: 65 adultos participaron en un club de lectura, asistiendo una vez al mes, durante 4 meses a un centro de investigación para conversar sobre libros científicos divulgativos de alimentación/nutrición. Se llevó a cabo un seguimiento de los conocimientos de los participantes a través de una encuesta realizada en todas las sesiones del club de lectura. Resultados: Los participantes fueron en su mayoría mujeres con estudios universitarios. La asistencia a los clubs de lectura provocó un aumento significativo (P < 0,05) en el número de respuestas correctas en un cuestionario sobre las creencias erróneas comunes en los temas tratados en los libros discutidos. Conclusiones: Los clubs de lectura basados en libros de divulgación científica y dirigidos por científicos con experiencia en el campo pueden aumentar el conocimiento nutricional entre la población en general, debiéndose explorar más a fondo en diferentes contextos socioeconómicos., [EN] Introduction: The spread of false news related to nutrition shows the need to provide general public validated information on food and health, inducing them to follow healthy dietary habits. Objective: To assess whether attendance to book clubs devoted to scientific disseminations books is a useful strategy for improving nutritional knowledge among the population. Methodology: 65 adults participated in a reading club, attending a research center once a month for 4 months to talk about informative scientific books on food/nutrition. The knowledge of the participants was monitored through a survey performed in all the sessions of the club. Results: Participants were mostly female with university studies. Attendance to the book clubs caused a significant increase (P < 0.05) in the number of correct answers on a questionnaire about common misbeliefs on the topics covered in the discussed books. Participants showed a high degree of satisfaction with the activity and willingness to read more scientific dissemination books, even when most of them were not previously usual readers. Conclusions: Book clubs based on popular science books and led by scientists with expertise in the field could increase nutritional knowledge among general population, which should be further explored in different socioeconomic contexts.

Short-term gaseous treatments improve rachis quality during table grape postharvest, but little is known about the mechanisms involved. In this work, we observed that the application of a 3-day CO2 treatment at 0 °C improved rachis browning of Superior Seedless and Red Globe bunches, affecting the non-enzymatic antioxidant system by reducing the total phenolic content, the antioxidant activity and the expression of different stilbene synthase genes. Lipid peroxidation levels revealed lower oxidative stress in CO2-treated rachis of both cultivars linked to the activation of the enzymatic antioxidant system. Furthermore, whereas a positive correlation was denoted between rachis browning and the accumulation of key ABA regulatory genes in Red Globe bunches, this effect was restricted to ACS1, a key synthetic ethylene gene, in Superior Seedless clusters. This work also corroborated the important role of ethylene-responsive factors in the beneficial effect of the gaseous treatment, not only in the berries but also in the rachis. Finally, the application of the gaseous treatment avoided the induction of cell wall-degrading enzyme-related genes in both cultivars, which could favor the maintenance of rachis quality. This work provides new insight into specific responses modulated by the gaseous treatment focused on mitigating rachis browning independently of the cultivar.

One of the greatest threats to wild strawberries (Fragaria vesca Mara des Bois) after harvest is the highly perishability at ambient temperature. Breeders have successfully met the quality demands of consumers, but the prevention of waste after harvest in fleshy fruits is still pending. Most of the waste is due to the accelerated progress of senescence-like process after harvest linked to a rapid loss of water and firmness at ambient temperature. The storage life of strawberries increases at low temperature, but their quality is limited by the loss of cell structure. The application of high CO2 concentrations increased firmness during cold storage. However, the key genes related to resistance to softening and cell wall disassembly following transference from cold storage at 20°C remain unclear. Therefore, we performed RNA-seq analysis, constructing a weighted gene co-expression network analysis (WGCNA) to identify which molecular determinants play a role in cell wall integrity, using strawberries with contrasting storage conditions, CO2-cold stored (CCS), air-cold stored (ACS), non-cold stored (NCS) kept at ambient temperature, and intact fruit at harvest (AH). The hub genes associated with the cell wall structural architecture of firmer CO2-treated strawberries revealed xyloglucans stabilization attributed mainly to a down-regulation of Csl E1, XTH 15, Exp-like B1 and the maintenance of expression levels of nucleotide sugars transferases such as GMP and FUT as well as improved lamella integrity linked to a down-regulation of RG-lyase, PL-like and PME. The preservation of cell wall elasticity together with the up-regulation of LEA, EXPA4, and MATE, required to maintain cell turgor, is the mechanisms controlled by high CO2. In stressed air-cold stored strawberries, in addition to an acute softening, there is a preferential transcript accumulation of genes involved in lignin and raffinose pathways. Non-cold stored strawberries kept at 20°C after harvest are characteri

Soft fruits are appreciated for their taste qualities and for being a source of health-promoting compounds. However, their postharvest is affected by their high respiratory rates and susceptibility to fungal decay. Our aim here is to provide a perspective on the application of short-term high-CO2 treatments at a low temperature to maintain the postharvest quality of soft fruits. This work also suggests using a multi-omics approach to better understand the role of the cell wall and phenolic compounds in maintaining quality. Finally, the contribution of high-throughput transcriptomic technologies to understand the mechanisms modulated by the short-term gaseous treatments is also highlighted.

El objetivo de este estudio ha sido evaluar las propiedades físicas y químicas que determinan la calidad de arándanos (Vaccinium corymbosum L.) procedentes de grandes superficies (5 muestras), fruterías de barrio (3 muestras) y de agricultura ecológica (2 muestras). Para establecer su calidad, se analizaron diferentes parámetros tales como: acidez titulable, sólidos solubles totales, pH, contenido total de fenoles y antocianos, así como la actividad antioxidante determinada por los métodos ABTS y FRAP. Las muestras presentaron diferencias en los parámetros individuales analizados, pero todas ellas tuvieron una buena calidad global en el punto de venta. Es importante destacar que no hubo diferencias entre las condiciones de cultivo (ecológicos vs intensivo) en cuanto a la actividad antioxidante y el contenido en compuestos fenólicos y antocianos.

Medicago truncatula is a forage crop of choice for farmers, and it is a model species for molecular research. The growth and development and subsequent yields are limited by water availability mainly in arid and semi-arid regions. Our study aims to evaluate the morpho-physiological, biochemical and molecular responses to water deficit stress in four lines (TN6.18, JA17, TN1.11 and A10) of M. truncatula. The results showed that the treatment factor explained the majority of the variation for the measured traits. It appeared that the line A10 was the most sensitive and therefore adversely affected by water deficit stress, which reduced its growth and yield parameters, whereas the tolerant line TN6.18 exhibited the highest root biomass production, a significantly higher increase in its total protein and soluble sugar contents, and lower levels of lipid peroxidation with greater cell membrane integrity. The expression analysis of the DREB1B gene using RT-qPCR revealed a tissue-differential expression in the four lines under osmotic stress, with a higher induction rate in roots of TN6.18 and JA17 than in A10 roots, suggesting a key role for DREB1B in water deficit tolerance in M. truncatula.

Despite the fact that many studies have examined the effectiveness of different gaseous postharvest treatments applied at low temperature to maintain table grape quality, the use of ethanol vapor has hardly been investigated. Thus, this work has studied the effectiveness of ethanol vapor-generating sachets in the maintenance of It 681–30 table grape quality, a new cultivar, during storage at low temperature and after the shelf-life period at 20 °C. To this end, various quality assessments have been carried out and the effect of the ethanol treatment on the expression of different genes (phenylpropanoids, transcription factors, PRs, and aquaporins) was determined. The results indicated that the application of ethanol vapor reduced the total decay incidence, weight loss, and the rachis browning index in It 681–30 grapes stored at 0 °C and after the shelf-life period at 20 °C, as compared to non-treated samples. Moreover, the modulation of STS7 and the different PR genes analyzed seems to play a part in the molecular mechanisms activated to cope with fungal attacks during the postharvest of It 681–30 grapes, and particularly during the shelf-life period at 20 °C. Furthermore, the expression of aquaporin transcripts was activated in samples showing higher weight loss. Although further work is needed to elucidate the role of ethanol in table grape quality, the results obtained in this work provide new insight into the transcriptional regulation triggered by ethanol treatment.

We used an integrated morpho-physiological, biochemical, and genetic approach to investigate the salt responses of four lines (TN1.11, TN6.18, JA17, and A10) of Medicago truncatula. Results showed that TN1.11 exhibited a high tolerance to salinity, compared with the other lines, recording a salinity induced an increase in soluble sugars and soluble proteins, a slight decrease in malondialdehyde (MDA) accumulation, and less reduction in plant biomass. TN6.18 was the most susceptible to salinity as it showed less plant weight, had elevated levels of MDA, and lower levels of soluble sugars and soluble proteins under salt stress. As transcription factors of the APETALA2/ethylene responsive factor (AP2/ERF) family play important roles in plant growth, development, and responses to biotic and abiotic stresses, we performed a functional characterization of MtERF1 gene. Real-time PCR analysis revealed that MtERF1 is mainly expressed in roots and is inducible by NaCl and low temperature. Additionally, under salt stress, a greater increase in the expression of MtERF1 was found in TN1.11 plants than that in TN6.18. Therefore, the MtERF1 pattern of expression may provide a useful marker for discriminating among lines of M. truncatula and can be used as a tool in breeding programs aiming at obtaining Medicago lines with improved salt tolerance.

Dehydrins, a family of hydrophilic and intrinsically disordered proteins, are a subgroup of late embryogenesis abundant proteins that perform different protective roles in plants. Although the transition from a disordered to an ordered state has been associated with dehydrin function or interactions with specific partner molecules, the question of how the primary and secondary dehydrin protein structure is related to specific functions or target molecule preferences remains unresolved. This work addresses the in silico sequencing analysis and in vitro functional characterization of two dehydrin isoforms, VviDHN2 and VviDHN4, from Vitis vinifera. Conformational changes suggest potential interactions with a broad range of molecules and could point to more than one function. The in silico analysis showed differences in conserved segments, specific amino acid binding sequences, heterogeneity of structural properties and predicted sites accessible for various post-translational modifications between the sequence of both dehydrins. Moreover, in vitro functional analysis revealed that although they both showed slight antifungal activity, only VviDHN4 acts as a molecular shield that protects proteins from freezing and dehydration. VviDHN4 also demonstrated high potential as a chaperone and reactive oxygen species scavenger, in addition to presenting antifreeze activity, all of which confirms its multifunctional nature. Our findings highlight the significant role of Y-segments and the differential and specific amino acid composition of less conserved segments that are rich in polar/charged residues between S- and K-segments, coupled with post-translational modifications, in modulating and switching dehydrin biological function.

The application of one or two short-term treatments with high levels of CO2 during 3 days at 0 °C maintained the quality of Autumn Royal table grapes (Vitis vinifera) during storage at 0 °C. We have analyzed how the application of a 3-day gaseous treatment, for one or two times at 0 °C, influences on common (VviPAL, VviCHS, VviCHI, VviF3′H, VviF3′5′H, VviF3H and VviLDOX) and branch-specific (VviFLS1, VviLAR1, VviLAR2, VviANR and VviUFGT) flavonoid gene expression in the skin of Autumn Royal table grapes. Likewise, the content of flavonols, flavan-3-ols and anthocyanins were identified with Q-TOF equipment and quantified by HPLC-quadrupole together with the total phenolic content and the antioxidant capacity by the ABTS and FRAP methods. Moreover, we have also used a solid-state voltammetry methodology to compare the effect of the application of one or two gaseous treatments in the skin of table grapes stored at 0 °C. Results revealed that the application of one or two gaseous treatments modulated the expression of flavonoid gene expression and the levels of catechin, in the case of one application, or quercetin-3-glucoside and five anthocyanins in fruit treated twice, maintaining their levels after 28 days of storage at 0 °C similar to those recorded in freshly harvested fruit. Satisfactorily, the electrochemical approach was useful to distinguish between treated and non-treated samples not only in the first stage of storage but also after 16 days.

Sucrose is a key player in strawberry metabolism. However, the molecular mechanisms underlying sucrose status in strawberries during later ripening stages and postharvest storage remains quite limited. Therefore, we identified members of various gene families encoding key enzymes involved in sucrose metabolism, analyzed their expression profiles and determined the sugar content in strawberries at different ripening stages and postharvest treatments. Three different ripening stages around harvest time, almost red (AR), full red (FR) and dark red (DR) were analyzed, as well as after pre-treatment with high CO2 levels (18 % CO2, 2 d) during low temperature (LT) storage and further shelf-life at 20 °C. The accumulation of sucrose, hexoses, trehalose, myo-inositol, fructo-oligosaccharides (FOS) and raffinose family oligosaccharides (RFOs) was analyzed. Our results indicate that the transition from FR to DR stages was characterized by a prominent accumulation of hexoses, sucrose and a sharp decrease in the levels of FOS. We therefore suggest that FOS, in addition to their protective role in stressful conditions, are also important metabolic signals of the end of ripening process. The highest levels of RFOs was detected in strawberries at LT in air, making them a possible marker of damage, an idea reinforced too by the low RFOs and high myo-inositol quantities found in high CO2 protective treatment. Interestingly, the sucrose accumulation in fully ripe strawberries and in high CO2-treated ones was linked to a significant decrease in the expression of FvVIN2 (vacuolar invertase), an opposite trend to that observed in fruit stored in air. Furthermore, high levels of CO2 prevented both the upregulation of FvSS1 and the sharp increase in the expression of FvCWINV1 observed at low temperature in air. The efficiency of high CO2 pre-treatment on sucrose accumulation was particularly evident during the shelf-life period at 20 °C (SL) after LT storage. Our study provides new insigh

Woodland strawberry is highly perishable fruit susceptible to water loss and fungal attack. Low temperature is one of the common technologies to preserve fruit. However, Mara des Bois strawberries are susceptible to physiological damage when stored at temperatures close to 0ºC. In our laboratory, high CO2 pretreatment (2 days at 18 kPa CO2) coupled with low temperature during seven days at 1ºC was used. This treatment not only has to extend the storage period of strawberries but must also maintain the quality attributes at shelf-life and the moment of consumption. Among the flavour and sweetness attributes, we focused on how short-term high CO2 protective treatments specifically maintain sensorial and texture traits. In order to identify biomarkers to improve technologies for optimum fruit quality we performed a high-throughput RNA sequencing analysis to elucidate the molecular adaptation and metabolic pathways in response to high CO2 treatment. Differential gene expression (DESeq) and weighted gene correlation network analyses (WGCNA) have been performed to identify the main co-expressed and regulatory genes involved in the shelf-life of Fragaria vesca after low temperature storage with and without CO2 pretreatment. Several pathways involving cell wall homeostasis and carbohydrate metabolisms are presented and discussed. Advances in elucidating the molecular adaptation and metabolic pathways in response to high CO2 treatment will help to improve technologies for optimum fruit quality and expand the potential market of this high-value fruit.

Table grape is a fruit with increasing interest due to its attributes and nutritional compounds. During recent years, new cultivars such as those without seeds and with new flavors have reached countries around the world. For this reason, postharvest treatments that retain fruit quality need to be improved. However, little is known to date about the biochemical and molecular mechanisms related with observed quality improvements. This review aims to examine existing literature on the different mechanisms. Special attention will be placed on molecular mechanisms which activate and regulate the different postharvest treatments applied in order to improve table grape quality.

Cell membranes provide a link between postharvest disorders and their integrity is essential for reducing table grape deterioration due to dehydration and susceptibility to fungal infection. We examined the relationship between ultrastructural membrane integrity at the subcellular level (transmission electron microscopy), cell (H2O2 generation) and membrane (malondialdehyde accumulation) oxidative status, membrane fatty acid composition (polar lipid fraction) and berry quality in order to determine the critical membrane events associated with long-term storage disorders at 0 °C in table grapes (Vitis vinifera L.) cv. Autumn Royal, and evaluate their response to the application of a single or dual short-term 20 kPa CO2 treatment. The results revealed a progressive disorganization of the cytoplasm and the breakdown of the cell organelle ultrastructure, associated with elevated hydrogen peroxide generation and lipid peroxidation rates and an imbalance in the saturated/unsaturated ratio of polar lipids, mainly due to the decrease in the degree of unsaturation of 18-carbon fatty acids. Conversely, high CO2 levels maintained the integrity of the microstructure of cell and energy-related organelles that are essential for metabolic damage repair and cell membrane restoration, reduced oxidative damage in cells and membranes, and increased the unsaturation of 18-carbon fatty acids, lipid unsaturation ratio and index of unsaturated fatty acids (IUFA) in the membrane polar lipids. The results also revealed that the more short-term high CO2 treatment is applied to Autumn Royal grapes, the more cytological evidence there is of enhanced tolerance to long-term cold and prevention of storage disorders in terms of cluster weight loss, rachis browning, berry water loss and decay incidence.

Phenolic compounds, such as phytoalexin resveratrol, can be induced in grapes in response to biotic and abiotic stresses and have been related in many healthy effects. Stilbene synthases (STSs) are the key enzyme responsible for resveratrol biosynthesis. They have been already isolated and characterized from several plant species, however, VviSTS is a multigene family and little is known about their modulation in response to the application of gaseous treatments that maintain table grapes quality during postharvest. In this work, we have analyzed the effect of a 3-day CO2 treatment on the modulation of 4 STSs (VviSTS6, VviSTS7, VviSTS16 and VviSTS46) and on the accumulation of different stilbene compounds (resveratrol, resveratrol-glucoside, trans-piceatannol, z-miyabenol and pallidol) during the postharvest storage at 0 °C of white (Superior Seedless, Dominga), red (Red Globe) and black (Autumn Royal) table grapes. Results indicated that the accumulation of the stilbene compounds by the application of CO2 and low temperature storage were cultivar dependent. In white Dominga fruit, accumulation of stilbene compounds increased in CO2-treated samples what seems to be modulated by VviSTS6, VviSTS7 and VviSTS46. However, in Red Globe the accumulation of compounds was mainly due to the cold storage in air and seems to be also mediated by the induction of the same VviSTSs. By contrast, in Superior Seedless and Autumn Royal table grapes the modulation of VviSTSs genes and the stilbene accumulation was independent of the atmosphere storage. Further studies would be needed to elucidate the possible role of transcription factors involved on VviSTSs modulation.

[Bakghround]: In this study, we analyzed the effect of the application of high levels of CO2 (20 kPa CO2 + 20 kPa O2 + 60 kPa N2 ) for 3 days at low temperature on a white table-grape cultivar (Superior Seedless) in comparison with a black one (cv. Autumn Royal) in terms of quality parameters. We also used a solid-state voltammetry methodology to analyze the effect of the 3-day gaseous treatment in berry tissues from both cultivars in the first stage of storage. We determined the role of the non-enzymatic (total phenols, total anthocyanins, and antioxidant activity) and the enzymatic antioxidant (catalase (GCAT), ascorbate peroxidase (VcAPX) gene expression) systems in the behaviors of both cultivars. [Results]: Our results indicate that the application of a 3-day gaseous treatment was effective in maintaining the quality of black and white table grapes for up to 28 days of storage at 0 °C. The electrochemical methodology applied was useful for differentiating between skin and pulp samples, and between black and white table grape cultivars. Some molecular mechanisms were modulated in the skin of both cultivars to overcome oxidative stress, which was not manifested with the same intensity in grapes treated with CO2 for 3 days. However, some differences were observed in relation to the non-enzymatic system. [Conclusion]: The 3-day gaseous treatment was useful to maintain black and white table grape quality at 0 °C. The voltammetry analysis indicated that CO2 -treated samples from the skin and pulp showed more similarity to freshly harvested ones.

The role played by heat shock proteins (HSPs) in improving fruit quality during postharvest treatments has mainly been studied regarding heat treatments, while little is known about the effect of CO2 treatments. In this study, we have analyzed the gene expression of five heat shock proteins (HSPs) and one heat shock factor (HSF) in the skin of red table grapes (Vitis vinifera cv. Cardinal) to determine whether a pretreatment with high CO2 levels (20 kPa) modulated their expression and how the length of the treatment (1 or 3 d) could influence this change. The 3-d high CO2-treatment was effective in reducing total decay and induced the accumulation of three small HSPs (VviHSP18.1, VviHSP18.2 and VviHSP22.0), whereas VviHSP70.0 and VviHSF4-a gene expression were induced by both treatments. To shed light on the putative physiological role of a small HSP (VviHSP18.1) acting as a chaperone, the recombinant protein was overexpressed in Escherichia coli. It was then purified and mass spectrometry confirmed that the isolated protein was VviHSP18.1, belonging to class I sHSP. Although the purified protein was stable at different high temperatures, when temperature was above 70 °C, a weaker and smaller protein band appeared which was identified by mass spectrometry as VviHSP18.1 with a C-terminal truncation. The recombinant VviHSP18.1 protein displayed chaperone activity which protects citrate synthase (CS) and malate dehydrogenase (MDH) from thermal aggregation at 45 °C, and also displayed the protection of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) activities at 55 °C and 65 °C, respectively. By contrast, VviHSP18.1 did not protect LDH from freezing-induced inactivation. Taken together, these results support the hypothesis that a high CO2 treatment is an active process where HSPs could participate in preventing the denaturation and dysfunction of different proteins.

Strawberries are characterized by an intense flowery odor, which is associated with specific ester species. In this study, the effect of high CO2 atmospheres (0, 20 or 40 kPa) at 0°C on alcohol dehydrogenase (ADH) gene expression and on selected volatile esters of 'Mara des Bois' strawberries was analyzed. Acetaldehyde and ethanol concentrations, and those of hexanal and 1-hexanol were compared in strawberries stored under different high CO2 atmospheres. The abundance of each detected volatile esters varied as a function of CO2 concentration during storage. When compared with fruit at harvest, those stored at low temperature without added CO2 had a marked induction of ADH expression that was associated with the accumulation of 1-hexanol and esters typically related to fatty acid breakdown. Moreover, these fruit had the lowest concentrations of ethanol and some ethyl esters, such as ethyl butanoate. In contrast, a moderate accumulation of ethanol and specific esters associated with strawberry flavor were observed in fruit stored in a 20 kPa CO2. The shift towards ethanolic fermentation in fruit treated with 20 kPa CO2 for 3 days was associated with 1-hexanol accumulation. However, 40 kPa-treated fruit accumulated the lowest levels of octyl 3-methyl butanoate, the volatile ester with the strongest flavor in this cultivar. This reduction in conjunction with the accumulation of higher levels of acetaldehyde, ethanol and ethyl acetate could explain the negative impact on such fruits maintained in an excessively high CO2 atmosphere.