Blueberry Fruit Research Articles

The Identification, Separation, and Clamp Function of an Intelligent Flexible Blueberry Picking Robot

Identifying fruit maturity accurately and achieving damage-free harvesting are challenges in designing blueberry-picking robots. This paper presents an intelligent flexible picking system. First, we trained a deep learning-based YOLOv8n network to locate the position of the fruit and determine fruit ripeness. We used a neural network to establish the relationship between fruit hardness and shape parameters, achieving an adaptive gripping force for different fruits. To address the issue of dense clusters in some blueberry varieties, we designed a fruit separation subsystem using a combination of flow field analysis and pressure-sensitive experiments. The results show that the mean average precision can reach 84.62%, the precision is 94.49%, the recall is 83.85%, the F1 score is 88.85%, and the test time is 0.12 s, which can meet the requirements for blueberry fruit recognition accuracy and speed. The spacing between closely packed fruits can increase by 4 mm, and the damage-free picking rate exceeds 92%, achieving stable, damage-free harvesting.

Microencapsulation of Caucasian blueberries (Vaccinium arctostaphylos L.) anthocyanins: Colour stability in varying storage conditions

AbstractThe aim of this study was to investigate the extraction of anthocyanins from the fruits of Caucasian blueberry (Vaccinium arctostaphylos L.) and examine the colour stability of anthocyanins encapsulated through spray drying in model systems. The trials were conducted to determine the optimal conditions for anthocyanin extraction using an ultrasonic water bath at temperatures of 25, 50 and 75°C. The ideal anthocyanin extraction occurred at 25°C using 100% acetone in an ultrasonic bath for 15 min at 35 kHz. Anthocyanin concentrations were evaluated using the pH differential method. The extracted anthocyanins were encapsulated through spray drying with maltodextrin as the encapsulating material. The encapsulation efficiency was 80.4 ± 0.20%, and the anthocyanin retention rate was 83.0 ± 0.76%. The coloured capsules were added to model systems with pH values of 4.50, 5.00, 5.50 and 6.00. The colour values (L* 50.16 ± 0.05, a* 4.08 ± 0.04, b* −9.35 ± 0.01, H° 293.57 ± 0.15, C* 10.20 ± 0.03) were measured during varying storage conditions. The results showed, that colour loss began on the fifth day and this was accelerated with higher temperatures and pH values. It was found that encapsulation significantly preserved the stability of the blue colour and the loss of the blue colour followed first‐order reaction kinetics. The study showed that the blue colour of microcapsules was best preserved at pH 5.00 at 25°C. In this case, the measured total colour change (∆E) was 5.86, the activation energy (Ea) was 37.64 kJ/mol, and the half‐life (t1/2) was determined to be 19.08 days.

Authenticity markers of cultivated blueberries (Vaccinium sp.) and European wild blueberry (V. myrtillus) assessed by hyperspectral imaging and machine learning algorithms

The present study was undertaken to tackle food fraud in the food chain by developing a novel panel of analytical fingerprints to distinguish the fruit of bilberry (Vaccinium myrtillus), a wild European blueberry grown in Finland, from their commercial cultivated counterparts based on V. corymbosum or other originally American Vaccinium species. The analytical fingerprints were derived using hyperspectral imaging (HSI). The cultivated domestic blueberry samples from Finland (N = 188), those imported (N = 338), and domestic Finnish wild bilberry fruit (N = 247) were imaged using Specim IQ and FX17 HSI cameras. The fruit HSI data were then classified using seven machine learning model types. The supervised evolutionary feature selection algorithm was used to recognize the most separating subset of wavelengths (nm predictors, colors) between the fruit class labels, which were 1) wild bilberry fruit vs. cultivated blueberry fruit and 2) domestic cultivated blueberry fruit vs. imported cultivated blueberry fruit. Moreover, we ran 190,822 individual models and 54,137 predictor combinations to determine whether subsets or all wavelengths better distinguished fruit class labels. Overall, the best model type, the rbf kernel support vector machine (rbf-SVM), showed excellent prediction performance when classifying wild bilberries vs. cultivated blueberries with HSI data obtained using both camera types (4.1% and 3.2% holdout set errors). Also the rbf-SVM performed well when classifying domestic cultivated blueberries vs. those imported with HSI data obtained using an IQ camera (2.3% holdout set error). Our results showed that hyperspectral imaging could predict food fraud attempts concerning the Vaccinium fruit of different origin and species.

Sustained carbon import supports sugar accumulation and anthocyanin biosynthesis during fruit development and ripening in blueberry (Vaccinium ashei)

Fruit ripening is a highly coordinated process involving molecular and biochemical changes that collectively determine fruit quality. The underlying metabolic programs and their transitions leading to fruit ripening remain largely under-characterized in blueberry (Vaccinium sp.), which exhibits atypical climacteric behavior. In this study, we focused on sugar, acid and anthocyanin metabolism in two rabbiteye blueberry cultivars, Premier and Powderblue, during fruit development and ripening. Concentrations of the three major sugars, sucrose (Suc), glucose (Glc), and fructose (Fru) increased steadily during fruit development leading up to ripening, and increased dramatically by around 2-fold in ‘Premier’ and 2- to 3-fold in ‘Powderblue’ during the final stage of fruit ripening. Starch concentration was very low throughout fruit development in both cultivars indicating that it does not serve the role of a major transitory carbon (C) storage form in blueberry fruit. Together, these patterns indicate continued import of C, likely in the form of Suc, throughout blueberry fruit development. Concentrations of the predominant acids, malate and quinate, decreased during ripening, and may contribute to increased shikimate biosynthesis which, in-turn, allows for downstream phenylpropanoid metabolism leading to anthocyanin synthesis. Consistently, anthocyanin concentrations were highest in fully ripened blue fruit. Weighted gene co-expression network analysis (WGCNA) was performed using a ‘Powderblue’ fruit ripening transcriptome and targeted fruit metabolite concentration data. A ‘dark turquoise’ module positively correlated with sugars and anthocyanins, and negatively correlated with acids (malate, quinate), was identified. Gene Ontology (GO) enrichment analysis of this module identified transcripts related to sugar, acid, and phenylpropanoid metabolism pathways. Among these, increased transcript abundance of a VACUOLAR INVERTASE during ripening was consistent with sugar storage in the vacuole. In general, transcript abundance of the glycolysis pathway genes was upregulated during ripening. The transcript abundance of PHOSPHOENOLPYRUVATE (PEP) CARBOXYKINASE increased during fruit ripening and was negatively correlated with malate concentration, suggesting increased malate conversion to PEP, which supports anthocyanin production during fruit ripening. This was further supported by the co-upregulation of several anthocyanin biosynthesis-related genes. Together, this study provides insights into important metabolic programs, and their underlying gene expression patterns during fruit development and ripening in blueberry.

Object Detection in High-Resolution UAV Aerial Remote Sensing Images of Blueberry Canopy Fruits

Blueberries, as one of the more economically rewarding fruits in the fruit industry, play a significant role in fruit detection during their growing season, which is crucial for orchard farmers’ later harvesting and yield prediction. Due to the small size and dense growth of blueberry fruits, manual detection is both time-consuming and labor-intensive. We found that there are few studies utilizing drones for blueberry fruit detection. By employing UAV remote sensing technology and deep learning techniques for detection, substantial human, material, and financial resources can be saved. Therefore, this study collected and constructed a UAV remote sensing target detection dataset for blueberry canopy fruits in a real blueberry orchard environment, which can be used for research on remote sensing target detection of blueberries. To improve the detection accuracy of blueberry fruits, we proposed the PAC3 module, which incorporates location information encoding during the feature extraction process, allowing it to focus on the location information of the targets and thereby reducing the chances of missing blueberry fruits. We adopted a fast convolutional structure instead of the traditional convolutional structure, reducing the model’s parameter count and computational complexity. We proposed the PF-YOLO model and conducted experimental comparisons with several excellent models, achieving improvements in mAP of 5.5%, 6.8%, 2.5%, 2.1%, 5.7%, 2.9%, 1.5%, and 3.4% compared to Yolov5s, Yolov5l, Yolov5s-p6, Yolov5l-p6, Tph-Yolov5, Yolov8n, Yolov8s, and Yolov9c, respectively. We also introduced a non-maximal suppression algorithm, Cluster-NMF, which accelerates inference speed through matrix parallel computation and merges multiple high-quality target detection frames to generate an optimal detection frame, enhancing the efficiency of blueberry canopy fruit detection without compromising inference speed.

Ultrasound as a Physical Elicitor to Improve Texture in Blueberry Fruit: Physiological Indicator and Transcriptomic Analysis.

Ultrasound (US) washing has been verified to improve the quality of postharvest blueberry fruit. However, its physiological and molecular mechanisms remain largely unknown. In the present study, an US with a frequency of 25 kHz and a power density of 400 W for 2 min was performed to investigate its role in impacting the quality of blueberries. The results showed that US washing improved the quality of blueberries, with a higher firmness and lignin content (p < 0.05) than the control. Moreover, US washing inhibited the levels of superoxide radical (O2·-) production rate and hydrogen peroxide (H2O2) content while stimulating the superoxide dismutase (SOD) and catalase (CAT) activities of the blueberry fruit. Transcriptomic analysis screened 163 differentially expressed genes (DEGs), and the key DEGs were mainly enriched in phenylpropanoid biosynthesis, flavonoid biosynthesis, and plant-pathogen interaction pathways. Furthermore, the transcription factors and the structural genes associated with lignin biosynthesis were also identified from the DEGs. More importantly, the correlation analysis revealed that firmness and lignin content were positively correlated with the expression of C4H, COMT1, and POD52 in blueberry fruit, indicating that these genes might be involved in the regulation of US-mediated lignin synthesis. The findings provide new insight into the US-enhanced quality of blueberry fruits.

Nondestructively Determining Soluble Solids Content of Blueberries Using Reflection Hyperspectral Imaging Technique

Effectively detecting the quality of blueberries is crucial for ensuring that high-quality products are supplied to the fresh market. This study developed a nondestructive method for determining the soluble solids content (SSC) of blueberry fruit by using a near-infrared hyperspectral imaging technique. The reflection hyperspectral images in the 900–1700 nm waveband range were collected from 480 fresh blueberry samples. An image analysis pipeline was developed to extract the spectrums of blueberries from the hyperspectral images. A regression model for quantifying SSC values was successfully established based on the full range of wavebands, achieving the highest RP2 of 0.8655 and the lowest RMSEP value of 0.4431 °Brix. Furthermore, three variable selection methods, namely the Successive Projections Algorithm (SPA), interval PLS (iPLS), and Genetic Algorithm (GA), were utilized to identify the feature wavebands for modeling. The models calibrated from feature wavebands generated an RMSEP of 0.4643 °Brix, 0.4791 °Brix, and 0.4764 °Brix, as well as the RP2 of 0.8507, 0.8397, and 0.8420 for SPA, iPLS, and GA, respectively. Furthermore, a pseudo-color distribution diagram of the SSC values within blueberries was successfully generated based on established models. This study demonstrated a novel approach for blueberry quality detection and inspection by jointly using hyperspectral imaging and machine learning methodologies. It can serve as a valuable reference for the development of grading equipment systems and portable testing devices for fruit quality assurance.

Production and quality of ‘Delite’ blueberry fruit under different pruning times

Production and quality of ‘Delite’ blueberry fruit under different pruning times

Calcium nanoparticles produced by Acacia arabica leaf extract and their influence on fresh-cut fruit quality features

Calcium oxide nanoparticles have possessed unique structural and numerous applications, including the food preservative, antimicrobial, and chemotherapeutic properties. The study’s goal was to identify and create calcium oxide-derived leaf extract nanoparticles from Acacia arabica (AA) and assess their effectiveness on fresh-cut fruit quality attributes. The calcium oxide nanoparticles (AACaN) produced using AA leaf extract by the simple precipitation method and the AACaN obtained were characterised and confirmed using various analytical techniques. Freshly sliced apple fruit as well as unsliced blueberry and blackberry were immersed in AACaN (10 and 20 µg/mL) at two different concentrations for five minutes before being put in packed polypropylene plastic bags and maintained at 5 °C. According to the quality evaluations of pH, DPPH, 2,2-diphenylpicrylhydrazyl (DPPH), hardness, total soluble solid content (TSS), and sensory analysis. AACaN at 20 µg/mL has the ability to preserve freshly cut fruits of apples as well as unsliced blueberries and blackberries, thereby effectively extending fruits 20-day shelf life in comparison to control (untreated) fruits. This study has concluded that the AA is an ideal source to synthesis calcium oxide nanoparticles, and it was proved by materially characterizing. Moreover, the AACaN at 20 µg/mL proved the apples, blueberry, and blackberry fruits shelf life, which also added a large nutritional value while maintaining a storage quality.

Biodiversity in nutrients and biological activities of 14 highbush blueberry (Vaccinium corymbosum L.) cultivars

The present study aimed to identify nutrients (UPLC-PDA-ESI-MS/MS, HPLC-RI method) and biological activities (antioxidant activity to reduce Fe3+ and ABTS·+, pancreatic lipase inhibitory effect, α-amylase, and α-glucosidase, anti-bacterial) of 14 highbush blueberries (Vaccinium corymbosum L.) cultivars (Northern type) as well as a principal component analysis (PCA) to assess the variation of these properties in the context of biodiversity. Most of the cultivars in this research have been first presented in this paper. Phytochemical profiling of the tested highbush blueberry fruit revealed 75 bioactive compounds, including 5 macroelements, 7 microelements, 7 monophosphate nucleotides, 15 anthocyanins, 1 phenolic acid, 14 flavonols, 11 essential amino acids, 8 non-essential amino acids, 2 sugars, 7 organic acids. The PCA showed that the profile and contents of the analyzed compounds as well as their anti-bacterial, antioxidant, anti-diabetic, and anti-obesity potentials depended significantly on the tested cultivars. Thus, the study provides comprehensive data on cultivar-specific biodiversity and correlations that can be used to design novel extracts rich in polyphenolic, amino acids, and/or minerals extracts from the selected cultivars of highbush blueberry as natural and alternative sources to fulfill the growing industry demand for supplements, pharmaceuticals, and nutraceutical products.

Exogenous deferoxamine mesylate suppresses iron-dependent ferroptosis in postharvest fruit rot of blueberry caused by Alternaria alternata and Fusarium fujikuroi

Plant development relies heavily on regulated cell death, which is crucial for specific plant responses to biological stresses. Ferroptosis, an iron-dependent, oxidative, and non-apoptotic cell death form, has been recently discovered in animal cells. In this study, we investigated whether a ferroptosis-like process could be relevant to cell death in postharvest fruit rot of blueberry caused by Alternaria alternata and Fusarium fujikuroi. The results showed that deferoxamine mesylate and glutathione (GSH) treated fruit showed enhanced disease resistance with lower lesion areas, whereas an opposite result was observed in hydrogen peroxide (H2O2) treatment, indicating that intracellular ferroptosis might exist in the fungal infected blueberry fruit. Compared to control, deferoxamine mesylate or GSH treatment improved chlorophyll fluorescence parameters, which contributed to the stability of photosynthesis. In terms of ferroptosis pathway in the adjacent area of infected fruit, deferoxamine mesylate suppressed an iron-dependent cell death pathway that was characterized by depletion of H2O2 and MDA and accumulation of GSH, as well as the reduction of ferrous ions and total iron ions. Meanwhile, deferoxamine mesylate could effectively delay the decrease rate of unsaturation value and key phospholipids of fungi infected fruit during storage, which possibly maintained the integrity of cell membrane. Due to the serious rot of the lesion area, the peroxidation of membrane lipids was severe, accompanied by metabolic disorders. These combined results demonstrated that deferoxamine mesylate treatment could reduce Fenton reaction by chelating Fe2+ and avoid excessive accumulation of reactive oxygen species (ROS), suppress iron-dependent ferroptosis, thereby maintaining fruit quality and reducing postharvest diseases.

Green-synthesized silver nanoparticles immobilized on graphene oxide for fruit preservation in alginate films

In this study, silver nanoparticles were synthesized by redox method using tea polyphenol as a reducing agent. These nanoparticles were then immobilized within sodium alginate (SA) composite films using graphene oxide (Go), resulting in films with enhanced food preservation capabilities. Initially, the synthesized silver nanoparticles underwent characterization through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). This characterization affirmed the successful synthesis of silver nanoparticles. Subsequently, the impact of silver nanoparticles and graphene oxide on the properties of the SA composite films was investigated. The SA composite films were analyzed barrier, mechanical, thermal stability, and functional properties. The findings revealed that the inclusion of silver nanoparticles immobilized in Go augmented the tensile strength (23.6 %), degradation temperature of the films, reduced water vapor permeability, and exhibited antioxidant properties (4.16 %–42.09 %), and antimicrobial activities against Escherichia coli and Staphylococcus aureus (19.79–20.37 times). The graphene oxide immobilizes the silver nanoparticles, thereby reducing the release concentration. Packaging blueberry fruits with the SA composite film impregnated with Go-immobilized silver nanoparticles reduced weight loss and wrinkle index and this enhanced blueberry fruit shelf life. Thus, this work presents a novel approach to preparing antimicrobial packaging films for post-harvest fruit preservation.

Phosphoproteomic Analysis Indicates Phosphorylated Proteins in Response to Postharvest Blueberries Fruit Softening during Shelf Life.

Postharvest blueberry fruit is prone to softening. Protein phosphorylation is an important post-translational modification that was involved in fruit softening. However, little is known about protein phosphorylation in postharvest blueberry fruit softening. The firmness, the apparent morphology, and cell structures of blueberry fruit were changed. As the decay rate of postharvest blueberry fruit increased, the soluble solid and titrable acid contents decreased significantly. Phosphoproteomic sequencing results showed that there were 4100 phosphorylated peptides, 5635 phosphorylated sites, and 1437 phosphorylated proteins and showed significant differences on 0 and 8 d. The GO database and KEGG pathway results indicated that these phosphorylated proteins were mainly involved in "biological process", "molecular function", "plant hormone signal transduction", and "metabolic pathways". Besides, a number of phosphorylated proteins were found in cell wall metabolism, plant hormone signaling, primary metabolism, energy metabolism, membrane and transport, ubiquitination-based proteins, and other metabolisms.

Blueberry (Vaccinium spp.) Anthocyanins and Their Functions, Stability, Bioavailability, and Applications.

Blueberry fruits are rich in anthocyanins. There are 25 known anthocyanidins found in blueberries (Vaccinium spp.) until now. Anthocyanins found in blueberries have attracted considerable interest for their outstanding abilities as antioxidants, anti-inflammatory agents, anti-diabetic, anti-obesity, and neuroprotection compounds, as well as their potential for preventing cardiovascular diseases, protecting vision, and inhibiting cancer development. However, their application is constrained by issues related to instability and relatively low bioavailability. Thus, this review provides a detailed overview of categories, functions, stability, and bioavailability of blueberry anthocyanins and their practical applications. The available studies indicate that there is more potential for the industrial production of blueberry anthocyanins.

Effects of cadmium stress on the growth, physiology, mineral uptake, cadmium accumulation and fruit quality of 'Sharpblue' blueberry

Cadmium (Cd) contamination is becoming a widespread environmental problem, and Cd toxicity risk is increasing in blueberries, typical acidophilous plants. However, studies on the physiological mechanisms of Cd toxicity affecting the growth of blueberry plants and fruits remain limited. Herein, a pot experiment involving four treatments, CK (0 mg·kg−1), Cd1 (2.5 mg·kg−1), Cd2 (15 mg·kg−1) and Cd3 (50 mg·kg−1), was conducted to investigate the effects of Cd stress on the growth, fruit quality, physiological characteristics, mineral composition and Cd uptake of 'Sharpblue' blueberry cuttings, and relationships between physicochemical indices and phenotypic data under Cd stress were analyzed via principal component analysis and Mantel's test. Compared with CK, Cd treatment led to chlorosis (decrease in SPAD and N content) in 'Sharpblue' leaves and inhibited increases in plant height, basal stem, crown width and biomass (dry weight), with the most significant changes in the 50 mg·kg−1 Cd treatment. The size and thickness of the upper epidermal cells, as well as the thickness of the palisade mesophyll and spongy tissues of 'Sharpblue' were significantly reduced at Cd > 15 mg·kg−1, while the density of stomata was significantly increased. Moreover, Cd stress reduced the yield (decrease in size and single-fruit weight) and quality (decrease in anthocyanin, flavonoid and total phenol content and increase in titratable acid content) of 'Sharpblue' fruits, and Cd content in fruit exceeded the Chinese food safety threshold of 0.05 mg·kg−1 when Cd > 15 mg·kg−1. The Cd enrichment capacity of different organs of 'Sharpblue' plants was in the following order: root > shoot > leaf > fruit, and the 50 mg·kg−1 Cd treatment significantly inhibited the uptake of Fe, Mn, Cu, and Zn. Additionally, 'Sharpblue' plants responded to H2O2 and malondialdehyde accumulation in different organs under Cd stress by regulating levels of osmoregulatory substances (soluble protein (SP), soluble sugar, and proline) and altering the activities of catalase, superoxide dismutase, ascorbic acid, and glutathione in the antioxidant system. Finally, correlation analysis revealed that Mg, Fe, Mn, Cu, Cd, H2O2, SP, SPAD, N, anthocyanin, titratable acid, flavonoids, and total phenols were strongly correlated with 'Sharpblue' growth, leaf and fruit phenotype under Cd stress. These findings provide theoretical information for soil safety management and the breeding of Cd-tolerant cultivars during blueberry cultivation, as well as for the study of Cd stress response mechanisms in acidophilous plants.

Genotypic variation in blueberry flower morphology and nectar reward content affects pollinator attraction in a diverse breeding population

BackgroundPollination is crucial to obtaining optimal blueberry yield and fruit quality. Despite substantial investments in seasonal beekeeping services, blueberry producers consistently report suboptimal pollinator visitation and fruit set in some cultivars. Flower morphology and floral rewards are among the key factors that have shown to contribute to pollinator attraction, however little is known about their relative importance for improving yield in the context of plant breeding. Clarifying the relationships between flower morphology, nectar reward content, pollinator recruitment, and pollination outcomes, as well as their genetic components, can inform breeding priorities for enhancing blueberry production. In the present study, we measured ten flower and nectar traits and indices of successful pollination, including fruit set, seed count, and fruit weight in 38 southern highbush blueberry genotypes. Additionally, we assessed pollinator visitation frequency and foraging behavior over two growing seasons. Several statistical models were tested to optimize the prediction of pollinator visitation and pollination success, including partial least squares, BayesB, ridge-regression, and random forest.ResultsRandom forest models obtained high predictive abilities for pollinator visitation frequency, with values of 0.54, 0.52, and 0.66 for honey bee, bumble bee, and total pollinator visits, respectively. The BayesB model provided the most consistent prediction of fruit set, fruit weight, and seed set, with predictive abilities of 0.07, -0.08, and 0.42, respectively. Variable importance analysis revealed that genotypic differences in nectar volume had the greatest impact on honey bee and bumble bee visitation, although preferences for flower morphological traits varied depending on the foraging task. Flower density was a major driving factor attracting nectar-foraging honey bees and bumble bees, while pollen-foraging bumble bees were most influenced by flower accessibility, specifically corolla length and the length-to-width ratio.ConclusionsHoney bees comprised the majority of pollinator visits, and were primarily influenced by nectar volume and flower density. Corolla length and the length-to-width ratio were also identified as the main predictors of fruit set, fruit weight, seed count, as well as pollen-foraging bumble bee visits, suggesting that these bees and their foraging preferences may play a pivotal role in fruit production. Moderate to high narrow-sense heritability values (ranging from 0.30 to 0.77) were obtained for all floral traits, indicating that selective breeding efforts may enhance cultivar attractiveness to pollinators.

Genome-wide characterization of DELLA gene family in blueberry (Vaccinium darrowii) and their expression profiles in development and response to abiotic stress

BackgroundThe DELLA proteins, a class of GA signaling repressors, belong to the GRAS family of plant-specific nuclear proteins. Members of DELLA gene family encode transcriptional regulators with diverse functions in plant development and abiotic stress responses. To date, DELLAs have been identified in various plant species, such as Arabidopsis thaliana, Malus domestica, Populus trichocarpa, and other land plants. Most information of DELLA family genes was obtained from A. thaliana, whereas little is known about the DELLA gene family in blueberry.ResultsIn this study, we identified three DELLA genes in blueberry (Vaccinium darrowii, VdDELLA) and provided a complete overview of VdDELLA gene family, describing chromosome localization, protein properties, conserved domain, motif organization, and phylogenetic analysis. Three VdDELLA members, containing two highly conserved DELLA domain and GRAS domain, were distributed across three chromosomes. Additionally, cis-acting elements analysis indicated that VdDELLA genes might play a critical role in blueberry developmental processes, hormone, and stress responses. Expression analysis using quantitative real-time PCR (qRT-PCR) revealed that all of three VdDELLA genes were differentially expressed across various tissues. VdDELLA2 was the most highly expressed VdDELLA in all denoted tissues, with a highest expression in mature fruits. In addition, all of the three VdDELLA genes actively responded to diverse abiotic stresses. Based on qRT-PCR analysis, VdDELLA2 might act as a key regulator in V. darrowii in response to salt stress, whereas VdDELLA1 and VdDELLA2 might play an essential role in cold stress response. Under drought stress, all of three VdDELLA genes were involved in mediating drought response. Furthermore, their transiently co-localization with nuclear markers in A. thaliana protoplasts demonstrated their transcriptional regulator roles.ConclusionsIn this study, three VdDELLA genes were identified in V. darrowii genome. Three VdDELLA genes were closely related to the C. moschata DELLA genes, S. lycopersicum DELLA genes, and M. domestica DELLA genes, respectively, indicating their similar biological functions. Expression analysis indicated that VdDELLA genes were highly efficient in blueberry fruit development. Expression patterns under different stress conditions revealed the differentially expressed VdDELLA genes responding to salt, drought, and cold stress. Overall, these results enrich our understanding of evolutionary relationship and potential functions of VdDELLA genes, which provide valuable information for further studies on genetic improvement of the plant yield and plant resistance.

Does photoselective netting influence ripening, maturity parameters and chemical composition of highbush blueberry (Vaccinium corymbosum L.) fruit?

The use of photoselective nets in highbush blueberry orchards has attracted much interest in recent years. In our 2-year experiment, we evaluated the effect of black, red, yellow and white exclusion nets and an uncovered control on light quantity and quality, fruit maturity parameters and chemical composition at harvest. Significant differences between treatments were noticed in fruit peel color, firmness and total soluble solids (TSS) content in both experimental years. The content of total volatiles in 2022 was the highest under the red net (2.67 mg kg−1) and the control (2.63 mg kg−1), to which the contents of hexanal and (E)-2-Hexenal contributed the most. No significance in total volatiles was determined in 2023. The sugar/organic acid ratio was the lowest in fruit under the yellow net (4.62) and the highest under the black net (7.74). Total phenolic, total anthocyanin and petunidin-3-O-glucoside contents were the highest in fruit under the black net (3606 mg kg−1) and lowest in fruit under the white exclusion net (2072 mg kg−1). According to our results, the black net performed the best, regarding the internal quality parameters, while the yellow net negatively affected the sugar/organic acid ratio and the white exclusion net negatively affected the total phenolic content.

Possible Mechanism of Sucrose and Trehalose-6-Phosphate in Regulating the Secondary Flower on the Strong Upright Spring Shoots of Blueberry Planted in Greenhouse.

Secondary flowering is the phenomenon in which a tree blooms twice or more times a year. Along with the development of blueberry (Vaccinium corymbosum L.) fruits in spring, a large number of secondary flowers on the strong upright spring shoots were noticed in blueberries planted in the greenhouse. To reveal the cause and possible regulatory mechanism of the phenomenon, we clarified the phenological characteristics of flower bud differentiation and development on the spring shoots by combining phenological phenotype with anatomical observation. Furthermore, the changes in carbohydrates, trehalose-6-phosphate (Tre6P), and the relationship among the key enzyme regulatory genes for Tre6P metabolism and the key regulatory genes for flower formation during the differentiation process of apical buds and axillary buds were investigated. The results showed that the process of flower bud differentiation and flowering of apical and axillary buds was consistent, accompanied by a large amount of carbohydrate consumption. This process was positively correlated with the expression trends of VcTPS1/2, VcSnRK1, VcFT, VcLFY2, VcSPL43, VcAP1, and VcDAM in general, and negatively correlated with that of VcTPP. In addition, there is a certain difference in the differentiation progress of flower buds between the apical and axillary buds. Compared with axillary buds, apical buds had higher contents of sucrose, fructose, glucose, Tre6P, and higher expression levels of VcTPS2, VcFT, VcSPL43, and VcAP1. Moreover, VcTPS1 and VcTPS2 were more closely related to the physiological substances (sucrose and Tre6P) in axillary bud and apical bud differentiation, respectively. It was suggested that sucrose and trehalose-6-phosphate play a crucial role in promoting flower bud differentiation in strong upright spring shoots, and VcTPS1 and VcTPS2 might play a central role in these activities. Our study provided substantial sight for further study on the mechanism of multiple flowering of blueberries and laid a foundation for the regulation and utilization of the phenomenon of multiple flowering in a growing season of perennial woody plants.

De novo biosynthesis of anthocyanins in Saccharomyces cerevisiae using metabolic pathway synthases from blueberry

BackgroundAnthocyanins are water-soluble flavonoids in plants, which give plants bright colors and are widely used as food coloring agents, nutrients, and cosmetic additives. There are several limitations for traditional techniques of collecting anthocyanins from plant tissues, including species, origin, season, and technology. The benefits of using engineering microbial production of natural products include ease of use, controllability, and high efficiency.ResultsIn this study, ten genes encoding enzymes involved in the anthocyanin biosynthetic pathway were successfully cloned from anthocyanin-rich plant materials blueberry fruit and purple round eggplant rind. The Yeast Fab Assembly technology was utilized to construct the transcriptional units of these genes under different promoters. The transcriptional units of PAL and C4H, 4CL and CHS were fused and inserted into Chr. XVI and IV of yeast strain JDY52 respectively using homologous recombination to gain Strain A. The fragments containing the transcriptional units of CHI and F3H, F3’H and DFR were inserted into Chr. III and XVI to gain Strain B1. Strain B2 has the transcriptional units of ANS and 3GT in Chr. IV. Several anthocyanidins, including cyanidin, peonidin, pelargonidin, petunidin, and malvidin, were detected by LC-MS/MS following the predicted outcomes of the de novo biosynthesis of anthocyanins in S. cerevisiae using a multi-strain co-culture technique.ConclusionsWe propose a novel concept for advancing the heterologous de novo anthocyanin biosynthetic pathway, as well as fundamental information and a theoretical framework for the ensuing optimization of the microbial synthesis of anthocyanins.