Fruit ripening: dynamics and integrated analysis of carotenoids and anthocyanins

Genetic tapestry of Capsicum fruit colors: a comparative analysis of four cultivated species

KEY MESSAGE

Genome-wide association study of color spaces across the four cultivated Capsicum spp. revealed a shared set of genes influencing fruit color, suggesting mechanisms and pathways across Capsicum species are conserved during the speciation. Notably, Cytochrome P450 of the carotenoid pathway, MYB transcription factor, and pentatricopeptide repeat-containing protein are the major genes responsible for fruit color variation across the Capsicum species. Peppers (Capsicum spp.) rank among the most widely consumed spices globally. Fruit color, serving as a determinant for use in food colorants and cosmeceuticals and an indicator of nutritional contents, significantly influences market quality and price. Cultivated Capsicum species display extensive phenotypic diversity, especially in fruit coloration. Our study leveraged the genetic variance within four Capsicum species (Capsicum baccatum, Capsicum chinense, Capsicum frutescens, and Capsicum annuum) to elucidate the genetic mechanisms driving color variation in peppers and related Solanaceae species. We analyzed color metrics and chromatic attributes (Red, Green, Blue, L*, a*, b*, Luminosity, Hue, and Chroma) on samples cultivated over six years (2015-2021). We resolved genomic regions associated with fruit color diversity through the sets of SNPs obtained from Genotyping by Sequencing (GBS) and genome-wide association study (GWAS) with a Multi-Locus Mixed Linear Model (MLMM). Significant SNPs with FDR correction were identified, within the Cytochrome P450, MYB-related genes, Pentatricopeptide repeat proteins, and ABC transporter family were the most common among the four species, indicating comparative evolution of fruit colors. We further validated the role of a pentatricopeptide repeat-containing protein (Chr01:31,205,460) and a cytochrome P450 enzyme (Chr08:45,351,919) via competitive allele-specific PCR (KASP) genotyping. Our findings advance the understanding of the genetic underpinnings of Capsicum fruit coloration, with developed KASP assays holding potential for applications in crop breeding and aligning with consumer preferences. This study provides a cornerstone for future research into exploiting Capsicum's diverse fruit color variation.

Qualitative Characteristics and Functional Properties of Cherry Tomato under Soilless Culture Depending on Rootstock Variety, Harvesting Time and Bunch Portion

Tomato grafting is an effective practice in increasing the profitability of fresh-market tomato cultivation, especially in greenhouses, and is also considered a strategy for enhancing fruit quality. In this study, selected quanti-qualitative traits, and the of bioactive health-promoting compound and organic acid contents of cherry tomato fruits from three different scion/rootstock combinations (Sunstream/Top Bental, Sunstream/Kaiser and Sunstream/Suzuka) grown under a greenhouse hydroponic system were evaluated in three different harvests (beginning, middle and end of the whole harvesting period) and on three different bunch portions (proximal, central and distal). Although the tomato productive performance was influenced by the rootstock, with Suzuka and Kaiser grafted plants showing the highest total marketable yield (9.8 kg plant-1, i.e., 20% more than Top Bental), the yield-related traits (bunch number, weight and length per plant, and fruit number per bunch) and the qualitative characteristics of the fruits (color, equatorial and polar diameters, dry matter and solid soluble contents, pH and titratable acidity) showed less variability, by displaying, along with the bioactive compound contents (total polyphenols, lycopene, β-carotene), DPPH free radical scavenging activity and organic acids contents (lactic and acetic), a significant effect of the harvesting time and bunch portion. Fruits from the beginning of the harvesting period showed better qualitative and functional properties, with the lycopene and β-carotene contents equal to 178.6 and 3 mg 100 g-1 fw, and fruits from proximal and central bunch portions had lycopene and β-carotene contents equal to 203.1 and 2.9 mg 100 g-1 fw.

Ascorbate peroxidase in fruits and modulation of its activity by reactive species

Ascorbate peroxidase (APX) is one of the enzymes of the ascorbate-glutathione cycle and is the key enzyme that breaks down H2O2 with the aid of ascorbate as an electron source. APX is present in all photosynthetic eukaryotes from algae to higher plants and, at the cellular level, it is localized in all subcellular compartments where H2O2 is generated, including the apoplast, cytosol, plastids, mitochondria, and peroxisomes, either in soluble form or attached to the organelle membranes. APX activity can be modulated by various post-translational modifications including tyrosine nitration, S-nitrosation, persulfidation, and S-sulfenylation. This allows the connection of H2O2 metabolism with other relevant signaling molecules such as NO and H2S, thus building a complex coordination system. In both climacteric and non-climacteric fruits, APX plays a key role during the ripening process and during post-harvest, since it participates in the regulation of both H2O2 and ascorbate levels affecting fruit quality. Currently, the exogenous application of molecules such as NO, H2S, H2O2, and, more recently, melatonin is seen as a new alternative to maintain and extend the shelf life and quality of fruits because they can modulate APX activity as well as other antioxidant systems. Therefore, these molecules are being considered as new biotechnological tools to improve crop quality in the horticultural industry.

Advances in genomics and genome editing for improving strawberry (Fragaria ×ananassa)

The cultivated strawberry, Fragaria ×ananassa, is a recently domesticated fruit species of economic interest worldwide. As such, there is significant interest in continuous varietal improvement. Genomics-assisted improvement, including the use of DNA markers and genomic selection have facilitated significant improvements of numerous key traits during strawberry breeding. CRISPR/Cas-mediated genome editing allows targeted mutations and precision nucleotide substitutions in the target genome, revolutionizing functional genomics and crop improvement. Genome editing is beginning to gain traction in the more challenging polyploid crops, including allo-octoploid strawberry. The release of high-quality reference genomes and comprehensive subgenome-specific genotyping and gene expression profiling data in octoploid strawberry will lead to a surge in trait discovery and modification by using CRISPR/Cas. Genome editing has already been successfully applied for modification of several strawberry genes, including anthocyanin content, fruit firmness and tolerance to post-harvest disease. However, reports on many other important breeding characteristics associated with fruit quality and production are still lacking, indicating a need for streamlined genome editing approaches and tools in Fragaria ×ananassa. In this review, we present an overview of the latest advancements in knowledge and breeding efforts involving CRISPR/Cas genome editing for the enhancement of strawberry varieties. Furthermore, we explore potential applications of this technology for improving other Rosaceous plant species.

Dietary Sources, Stabilization, Health Benefits, and Industrial Application of Anthocyanins-A Review

Natural phytochemicals are well known to protect against numerous metabolic disorders. Anthocyanins are vacuolar pigments belonging to the parent class of flavonoids. They are well known for their potent antioxidant and gut microbiome-modulating properties, primarily responsible for minimizing the risk of cardiovascular diseases, diabetes, obesity, neurodegenerative diseases, cancer, and several other diseases associated with metabolic syndromes. Berries are the primary source of anthocyanin in the diet. The color and stability of anthocyanins are substantially influenced by external environmental conditions, constraining their applications in foods. Furthermore, the significantly low bioavailability of anthocyanins greatly diminishes the extent of the actual health benefits linked to these bioactive compounds. Multiple strategies have been successfully developed and utilized to enhance the stability and bioavailability of anthocyanins. This review provides a comprehensive view of the recent advancements in chemistry, biosynthesis, dietary sources, stabilization, bioavailability, industrial applications, and health benefits of anthocyanins. Finally, we summarize the prospects and challenges of applications of anthocyanin in foods.

Emerging roles and mechanisms of lncRNAs in fruit and vegetables

With the development of genome sequencing technologies, many long non-coding RNAs (lncRNAs) have been identified in fruit and vegetables. lncRNAs are primarily transcribed and spliced by RNA polymerase II (Pol II) or plant-specific Pol IV/V, and exhibit limited evolutionary conservation. lncRNAs intricately regulate various aspects of fruit and vegetables, including pigment accumulation, reproductive tissue development, fruit ripening, and responses to biotic and abiotic stresses, through diverse mechanisms such as gene expression modulation, interaction with hormones and transcription factors, microRNA regulation, and involvement in alternative splicing. This review presents a comprehensive overview of lncRNA classification, basic characteristics, and, most importantly, recent advances in understanding their functions and regulatory mechanisms.

Comparative metabolomic analysis reveals nutritional properties and pigmentation mechanism of tea-scented rosehips

BACKGROUND

The fruits of the genus Rosa, commonly known as rosehips, have attracted significant attention owing to their rich content of various bioactive compounds. However, their utility is generally secondary to the ornamental appeal of their flowers. This study aimed to explore the quality differences among tea-scented rosehips found in Yunnan, China, including those of Rosa odorata var. odorata (RO), Rosa odorata var. gigantea (RG), and Rosa yangii (RY). Morphological characteristics, chemical composition, and antioxidant activity of their fruits were evaluated.

RESULTS

The study revealed significant variability in composition and biological activities based on fruit color. RO exhibited the highest levels of polyphenols, flavonoids, anthocyanins, carotenoids, and vitamin C, with the strongest antioxidant activity (10.99 μmol Trolox·g-1 ), followed by RG (7.91 μmol Trolox·g-1 ) and RY (6.52 μmol Trolox·g-1 ). This supports RO's potential as a functional food source. Untargeted metabolomics identified and quantified 502 metabolites, with flavonoids (171) and phenolic acids (147) as the main metabolites. The differential metabolites among the fruits are primarily enriched for flavonoid biosynthesis and phenylpropanoid biosynthesis pathways. Insights into color formation supported the role of anthocyanins, flavones, and flavonols in fruit color variation.

CONCLUSION

Tea-scented rosehips offer vibrant colors and high nutritional value with potent biological activities. Rosa odorata var. odorata stands out as a functional food source owing to its rich bioactive compounds. These findings lay the groundwork for utilizing rosehips in functional foods, health supplements, and food additives, emphasizing the practical and beneficial applications of Rosa spp. independent of their ornamental value. © 2023 Society of Chemical Industry.

Cytological characteristics of blueberry fruit development

Using the blueberry cultivar "Powderblue" after pollination, fruits at different developmental stages were collected for study. The transverse and longitudinal diameters, individual fruit weight, and fruit water content were measured during their development. Employing tissue sectioning and microscopy techniques, we systematically studied the morphological features and anatomical structures of the fruits and seeds at various developmental stages, aiming to elucidate the cytological patterns during blueberry fruit development. The results of our study revealed that the "Powderblue" blueberry fruit growth and development followed a double "S" curve. Mature "Powderblue" blueberries were blue-black in color, elliptical in shape, with five locules, an inferior ovary, and an average fruit weight of 1.73 ± 0.17 g, and a moisture content of 78.865 ± 0.9%. Blueberry fruit flesh cells were densely arranged with no apparent intercellular spaces, and mesocarp cells accounted for 52.06 ± 7.4% of fruit cells. In the early fruit development stages, the fruit flesh cells were rapidly dividing, significantly increasing in number but without greatly affecting the fruit's morphological characteristics. During the later stages of fruit development, the expansion of the fruit flesh cells became prominent, resulting in a noticeable increase in the fruit's dimensions. Except for the epidermal cells, cells in all fruit tissues showed varying degrees of rupture as fruit development progressed, with the extent of cell rupture increasing, becoming increasingly apparent as the fruit gradually softened. Additionally, numerous brachysclereids (stone cells) appeared in the fruit flesh cells. Stone cells are mostly present individually in the fruit flesh tissue, while in the placental tissue, they often group together. The "Powderblue" blueberry seeds were light brown, 4.13 ± 0.42 mm long, 2.2 ± 0.14 mm wide, with each fruit containing 50-60 seeds. The "Powderblue" seeds mainly consisted of the seed coat, endosperm, and embryo. The embryo was located at the chalazal end in the center of the endosperm and was spatially separated. The endosperm, occupying the vast majority of the seed volume, comprised both the chalazal and outer endosperm, and the endosperm developed and matured before the embryo. As the seed developed, the seed coat was gradually lignified and consisted of palisade-like stone cells externally and epidermal layer cells internally.

Chromosome-level genome assembly of navel orange cv. Gannanzao (Citrus sinensis Osbeck cv. Gannanzao)

Navel orange cv. Gannanzao is a variant of the navel orange cv. Newhall (Citrus sinensis Osbeck cv. Newhall) that exhibits an earlier maturation, making it commercially valuable. However, the mechanisms underlying its early maturation remain obscure. To address this question, we conducted genome sequencing and de novo assembly of navel orange cv. Gannanzao. The assembled genome sequence is 334.57 Mb in length with a GC content of 31.48%. It comprises 318 contigs (N50 = 3.23 Mb) and 187 scaffolds (N50 = 31.86 Mb). The Benchmarking Universal Single-Copy Orthologs test demonstrates 94.6% completeness. The annotation revealed 23,037 gene models, 164.95 Mb of repetitive sequences, and 2,554 noncoding RNAs. A comparative analysis identified 323 fruit ripening-related genes in navel orange cv. Gannanzao genome, while navel orange cv. Newhall genome contained 345 such genes. These genes were organized into 320 orthologous gene families, with 30.3% of them exhibiting differences in gene copy numbers between the 2 genomes. Additionally, we identified 15 fruit ripening-related genes that have undergone adaptive evolution, suggesting their potential role in advancing fruit maturation in navel orange cv. Gannanzao. Whole-genome sequencing and annotation of navel orange cv. Gannanzao provides a valuable resource to unravel the early maturation mechanism of citrus and enriches the genomic resources for citrus research.

Integrating the multiple functions of CHLH into chloroplast-derived signaling fundamental to plant development and adaptation as well as fruit ripening

Chlorophyll (Chl)-mediated oxygenic photosynthesis sustains life on Earth. Greening leaves play fundamental roles in plant growth and crop yield, correlating with the idea that more Chls lead to better adaptation. However, they face significant challenges from various unfavorable environments. Chl biosynthesis hinges on the first committed step, which involves inserting Mg2+ into protoporphyrin. This step is facilitated by the H subunit of magnesium chelatase (CHLH) and features a conserved mechanism from cyanobacteria to plants. For better adaptation to fluctuating land environments, especially drought, CHLH evolves multiple biological functions, including Chl biosynthesis, retrograde signaling, and abscisic acid (ABA) responses. Additionally, it integrates into various chloroplast-derived signaling pathways, encompassing both retrograde signaling and hormonal signaling. The former comprises ROS (reactive oxygen species), heme, GUN (genomes uncoupled), MEcPP (methylerythritol cyclodiphosphate), β-CC (β-cyclocitral), and PAP (3'-phosphoadenosine-5'-phosphate). The latter involves phytohormones like ABA, ethylene, auxin, cytokinin, gibberellin, strigolactone, brassinolide, salicylic acid, and jasmonic acid. Together, these elements create a coordinated regulatory network tailored to plant development and adaptation. An intriguing example is how drought-mediated improvement of fruit quality provides insights into chloroplast-derived signaling, aiding the shift from vegetative to reproductive growth. In this context, we explore the integration of CHLH's multifaceted roles into chloroplast-derived signaling, which lays the foundation for plant development and adaptation, as well as fruit ripening and quality. In the future, manipulating chloroplast-derived signaling may offer a promising avenue to enhance crop yield and quality through the homeostasis, function, and regulation of Chls.

Development of gelatin/agarose active coatings functionalized with Ocimum gratissimum L. essential oil for enhancing storability of 'Booth 7' avocado

Novel active coating from gelatin/agarose (GA) functionalized with Ocimum gratissimum L. essential oil (OGO) had been developed as a medium to evaluate their properties before being applied for avocado preservation. The resultant coating films showed enhanced mechanical, water-barrier, bactericidal, antioxidant, and UV-shielding properties by adding OGO. The best tensile strength (2.91 MPa) and flexibility (45.82 %) was found in the GA film containing 5 % (w/w) of OGO (GA-OGO-5). Furthermore, this coating formulation presented moderate antibacterial activities against Listeria, Pseudomonas, Salmonella, and Escherichia. The GA-OGO-5 coating film also divulged the highest hydrophobicity and adequate antioxidant function (30.75 μg/mL) and thus, was chosen to coat on 'Booth 7' avocados by dipping method. The GA-OGO-5 coating layers were to be efficient to decline the respiration rate of avocado during 6-day storage at 25 °C and 64 %RH. Peel color, weight loss (5.22 %), total soluble solids (8.14 %), and solution pH (6.79) at the end of storage also indicated that the GA-OGO-5 coating presented the best effectiveness for enhancing the storability of avocado as compared to uncoated and GA-treated fruit. Therefore, the GA-OGO coating has been considered as an alternative post-harvest technique to enhance the avocado storability and could be further commercialized for industry application.

Involvement of Transcription Factors and Regulatory Proteins in the Regulation of Carotenoid Accumulation in Plants and Algae

Carotenoids are essential for photosynthesis and photoprotection in photosynthetic organisms, which are widely used in food coloring, feed additives, nutraceuticals, cosmetics, and pharmaceuticals. Carotenoid biofortification in crop plants or algae has been considered as a sustainable strategy to improve human nutrition and health. However, the regulatory mechanisms of carotenoid accumulation are still not systematic and particularly scarce in algae. This article focuses on the regulatory mechanisms of carotenoid accumulation in plants and algae through regulatory factors (transcription factors and regulatory proteins), demonstrating the complexity of homeostasis regulation of carotenoids, mainly including transcriptional regulation as the primary mechanism, subsequent post-translational regulation, and cross-linking with other metabolic processes. Different organs of plants and different plant/algal species usually have specific regulatory mechanisms for the biosynthesis, storage, and degradation of carotenoids in response to the environmental and developmental signals. In plants and algae, regulators such as MYB, bHLH, MADS, bZIP, AP2/ERF, WRKY, and orange proteins can be involved in the regulation of carotenoid metabolism. And many more regulators, regulatory networks, and mechanisms need to be explored. Our paper will provide a basis for multitarget or multipathway engineering for carotenoid biofortification in plants and algae.

Anthocyanin in blood oranges: a review on postharvest approaches for its enhancement and preservation

Anthocyanin concentration is considered an important fruit quality index of blood oranges and has gained popularity among consumers due to its antioxidant capacity, therapeutic properties, and prevention of some human diseases. Anthocyanin biosynthesis occurs in the cytoplasmic face of the endoplasmic reticulum by multi-enzymes complexes through the flavonoid pathway. Polyphenoloxidase (PPO) and β-glucosidase (anthocyanase) are the enzymes responsible for anthocyanin degradation. Blood oranges are cold-dependent for anthocyanin biosynthesis and accumulation, and thus, the low temperature of storage can enhance anthocyanin concentration and improve internal fruit quality. In addition, anthocyanin accumulation can be accelerated by postharvest technologies, either physical treatments or chemical elicitors. However, low temperatures can induce chilling injury (CI) incidence in blood oranges. Postharvest chemical elicitors treatments can enhance anthocyanin accumulation and prevent CI. This review provides the most updated information about postharvest tools modulating the anthocyanin content, and the role of enhancing and preserving pigmentation to produce blood orange with the highest quality standards.

Identification and Profiling Analysis of microRNAs in Guava Fruit (Psidium guajava L.) and Their Role during Ripening

The guava (Psidium guajava L.) is a climacteric fruit with an accelerated post-harvest overripening. miRNAs are small RNA sequences that function as gene regulators in eukaryotes and are essential for their survival and development. In this study, miRNA libraries were constructed, sequenced and analyzed from the breaker and ripe stages of guava fruit cv. Siglo XXI. One hundred and seventy-four mature miRNA sequences from 28 miRNA families were identified. The taxonomic distribution of the guava miRNAs showed a high level of conservation among the dicotyledonous plants. Most of the predicted miRNA target genes were transcription factors and genes involved in the metabolism of phytohormones such as abscisic acid, auxins, and ethylene, as revealed through an ontology enrichment analysis. The miRNA families miR168, miR169, miR396, miR397, and miR482 were classified as being directly associated with maturation, whereas the miRNA families miR160, miR165, miR167, miR3930, miR395, miR398, and miR535 were classified as being indirectly associated. With this study, we intended to increase our knowledge and understanding of the regulatory process involved in the ripening process, thereby providing valuable information for future research on the ripening of guava fruit.

Transcriptome analysis reveals the mechanism of different fruit appearance between apricot (Armeniaca vulgaris Lam.) and its seedling

BACKGROUND

Apricot fruit has great economic value. In the process of apricot breeding using traditional breeding methods, we obtained a larger seedling (named Us) from the original variety (named U). And Us fruit is larger than U, taste better. Therefore, revealing its mechanism is very important for Apricot breeding.

METHODS

In this study, de novo assembly and transcriptome sequencing (RNA-Seq) was used to screen the differently expressed genes (DEGs) between U and Us at three development stages, including young fruits stage, mid-ripening stage and mature fruit stage.

RESULTS

The results showed that there were 6,753 DEGs at different sampling time. "Cellulose synthase (UDP-forming) activity" and "cellulose synthase activity" were the key GO terms enriched in GO, of which CESA and CSL family played a key role. "Photosynthesis-antenna proteins" and "Plant hormone signal transduction" were the candidate pathways and lhca, lhcb, Aux/IAA and SAUR were the main regulators.

CONCLUSION

The auxin signaling pathway was active in Us, of which Aux/IAAs and SAUR were the key fruit size regulators. The low level of lhca and lhcb in Us could reveal the low demand for exogenous carbon, but they increased at mature stage, which might be due to the role of aux, who was keeping the fruit growing. Aux and photosynthesis maight be the main causes of appearance formation of Us fruits. Interestingly, the higher expression of CESA and CSL proved that Us entered the hardening process earlier than U. The advanced developmental progress might also be due to the role of Aux.

The Effect of Ripening Stages on the Accumulation of Polyphenols and Antioxidant Activity of the Fruit Extracts of Solanum Species

The aim of the research was to evaluate the influence of the ripening stage on the accumulation of polyphenols and antioxidant activity in fruits of Solanum species. The experiment included two factors: I-four different Solanum species (S. melanocerasum, S. nigrum, S. villosum, and S. retroflexum) and II-three ripening stages. High-performance liquid chromatography (HPLC) was used to analyze the individual phenolic compounds (flavonoids and phenolic acids), and the spectrophotometric method was applied to determine antioxidant activity. The results revealed that the accumulation of polyphenols and antioxidant activity in fruits of Solanum species depends on the stage of ripening and species. All studied Solanum species fruits had the highest content of total phenolic acid at ripening stage III and the greatest antioxidant activity at ripening stage I. Fully ripe fruits of S. melanocerasum contained significantly more total flavonoids, whereas S. nigrum contained significantly more total phenolic acids than other investigated Solanum species fruits. The significantly highest antioxidant activity was found in S. melanocerasum fruits at ripening stage I.

Experimental approaches in studying active biomolecules modulating fruit ripening: Melatonin as a case study

Phytohormones are naturally occurring small organic molecules found at low concentrations in plants. They perform essential functions in growth and developmental processes, from organ initiation to senescence, including fruit ripening. These regulatory molecules are studied using different experimental approaches, such as performing exogenous applications, evaluating endogenous levels, and/or obtaining genetically modified lines. Here, we discuss the advantages and limitations of current experimental approaches used to study active biomolecules modulating fruit ripening, focusing on melatonin. Although melatonin has been implicated in fruit ripening in several model fruit crops, current knowledge is affected by the different experimental approaches used, which have given different and sometimes even contradictory results. The methods of application and the doses used have produced different results in studies based on exogenous applications, while different measurement methods and ways of expressing results explain most of the variability in studies using correlative analyses. Furthermore, studies on genetically modified crops have focused on tomato (Solanum lycopersicum L.) plants only. However, TILLING and CRISPR methodologies are becoming essential tools to complement the results from the experimental approaches described above. This will not only help the scientific community better understand the role of melatonin in modulating fruit ripening, but it will also help develop technological advances to improve fruit yield and quality in major crops. The combination of various experimental approaches will undoubtedly lead to a complete understanding of the function of melatonin in fruit ripening in the near future, so that this knowledge can be effectively transferred to the field.

Fruit Photosynthesis: More to Know about Where, How and Why

Not only leaves but also other plant organs and structures typically considered as carbon sinks, including stems, roots, flowers, fruits and seeds, may exhibit photosynthetic activity. There is still a lack of a coherent and systematized body of knowledge and consensus on the role(s) of photosynthesis in these "sink" organs. With regard to fruits, their actual photosynthetic activity is influenced by a range of properties, including fruit anatomy, histology, physiology, development and the surrounding microclimate. At early stages of development fruits generally contain high levels of chlorophylls, a high density of functional stomata and thin cuticles. While some plant species retain functional chloroplasts in their fruits upon subsequent development or ripening, most species undergo a disintegration of the fruit chloroplast grana and reduction in stomata functionality, thus limiting gas exchange. In addition, the increase in fruit volume hinders light penetration and access to CO₂, also reducing photosynthetic activity. This review aimed to compile information on aspects related to fruit photosynthesis, from fruit characteristics to ecological drivers, and to address the following challenging biological questions: why does a fruit show photosynthetic activity and what could be its functions? Overall, there is a body of evidence to support the hypothesis that photosynthesis in fruits is key to locally providing: ATP and NADPH, which are both fundamental for several demanding biosynthetic pathways (e.g., synthesis of fatty acids); O₂, to prevent hypoxia in its inner tissues including seeds; and carbon skeletons, which can fuel the biosynthesis of primary and secondary metabolites important for the growth of fruits and for spreading, survival and germination of their seed (e.g., sugars, flavonoids, tannins, lipids). At the same time, both primary and secondary metabolites present in fruits and seeds are key to human life, for instance as sources for nutrition, bioactives, oils and other economically important compounds or components. Understanding the functions of photosynthesis in fruits is pivotal to crop management, providing a rationale for manipulating microenvironmental conditions and the expression of key photosynthetic genes, which may help growers or breeders to optimize development, composition, yield or other economically important fruit quality aspects.

Bioactive Compounds, Antioxidant, and Antibacterial Activity Against MDR and Food-Borne Pathogenic Bacteria of Psidium guajava. L Fruit During Ripening

Psidium guajava fruits are highly appreciated for their nutrients and bioactive compounds content, which contribute to their antioxidant and antimicrobial capacities. The purpose of this study was to determine bioactive compound (phenolic, flavonoids, and carotenoid contents), antioxidant activity (DPPH, ABTS, ORAC, and FRAP), and antibacterial potential against MDR and food-borne pathogenic strains of Escherichia coli, and Staphylococcus aureus during different stages of fruit ripening.The results elucidated that ripe fruits (methanolic extract) contain the highest total phenolic, flavonoids, and carotenoid contents (417.36 ± 2.63 µg GAE/gm of FW, 711.78 ± 0.70 µg QE/gm of FW and 0.683 ± 0.06 µg/gm of FW) followed by hexane, ethyl acetate, and aqueous. Methanolic extract of the ripe fruits showed the highest antioxidant activity when measured by DPPH (61.55 ± 0.91%), FRAP (31.83 ± 0.98 mM Fe(II)/gm of FW), ORAC (17.19 ± 0.47 mM TE/ gm of FW), and ABTS (41.31 ± 0.99 µmol Trolox/gm of FW) assays. In the antibacterial assay, the ripe stage had the highest antibacterial activity against MDR and food-borne pathogenic strains of Escherichia coli, and Staphylococcus aureus. The methanolic ripe extract was found to possess maximum antibacterial activity ZOI, MIC, and IC50 18.00 ± 1.00 mm, 95.95 ± 0.05%, and 0.58 μg/ml; 15.66 ± 0.57 mm, 94.66 ± 0.19%, and 0.50 μg/ml, respectively, against pathogenic and MDR strains of E. coli and 22.33 ± 0.57 mm, 98.97 ± 0.02%, and 0.26 μg/ml; 20.33 ± 1.15 mm, 96.82 ± 0.14%, and 0.39 μg/ml, respectively, against pathogenic and MDR strains of S. aureus. Considering the bioactive compounds and beneficial effects, these fruit extracts could be promising antibiotic alternatives, avoiding antibiotic overuse and its negative effects on human health and the environment, and can be recommended as a novel functional food.

Investigating the Physiological and Molecular Responses of Solanum lycopersicum hp Mutants to Light of Different Quality for Biotechnological Applications

The effect of the light of different spectral compositions, white fluorescent light (WFL), red light (RL, 660 nm), blue light (BL, 450 nm), green light (GL, 525 nm), and white LED light (WL, 450 + 580 nm), on the physiological parameters of Solanum lycopersicum 3005 hp-2 (defective for a DET1 gene) and 4012 hp-1w; 3538 hp-1; 0279 hp-1.2 (defective for a DDB1a gene) photomorphogenetic mutants was studied. The parameters of the primary photochemical processes of photosynthesis, photosynthetic and transpiration rates, the antioxidant capacity of low-molecular weight antioxidants, the content of the total phenolic compounds, including flavonoids, and the expression of the genes involved in light signaling and biosynthesis of secondary metabolites were determined. Under BL, the 3005 hp-2 mutant showed the highest nonenzymatic antioxidant activity, which occurred to a greater extent due to the increase in flavonoid content. At the same time, under BL, the number of secretory trichomes on the surface of the leaves of all mutants increased equally. This suggests the accumulation of flavonoids inside leaf cells rather than in trichomes on the leaf surface. The data obtained indicate the possibility of using the hp-2 mutant for biotechnology to increase its nutritional value by enhancing the content of flavonoids and other antioxidants by modulating the spectral composition of light.

Analyzing the Quality Parameters of Apples by Spectroscopy from Vis/NIR to NIR Region: A Comprehensive Review

Spectroscopic methods deliver a valuable non-destructive analytical tool that provides simultaneous qualitative and quantitative characterization of various samples. Apples belong to the world's most consumed crops and with the current challenges of climate change and human impacts on the environment, maintaining high-quality apple production has become critical. This review comprehensively analyzes the application of spectroscopy in near-infrared (NIR) and visible (Vis) regions, which not only show particular potential in evaluating the quality parameters of apples but also in optimizing their production and supply routines. This includes the assessment of the external and internal characteristics such as color, size, shape, surface defects, soluble solids content (SSC), total titratable acidity (TA), firmness, starch pattern index (SPI), total dry matter concentration (DM), and nutritional value. The review also summarizes various techniques and approaches used in Vis/NIR studies of apples, such as authenticity, origin, identification, adulteration, and quality control. Optical sensors and associated methods offer a wide suite of solutions readily addressing the main needs of the industry in practical routines as well, e.g., efficient sorting and grading of apples based on sweetness and other quality parameters, facilitating quality control throughout the production and supply chain. This review also evaluates ongoing development trends in the application of handheld and portable instruments operating in the Vis/NIR and NIR spectral regions for apple quality control. The use of these technologies can enhance apple crop quality, maintain competitiveness, and meet the demands of consumers, making them a crucial topic in the apple industry. The focal point of this review is placed on the literature published in the last five years, with the exceptions of seminal works that have played a critical role in shaping the field or representative studies that highlight the progress made in specific areas.

Post-Harvest Red- and Far-Red-Light Irradiation and Low Temperature Induce the Accumulation of Carotenoids, Capsaicinoids, and Ascorbic Acid in Capsicum annuum L. Green Pepper Fruit

Environmental factors, such as light of different spectral compositions and temperature, can change the level of activated photoreceptors which, in turn, can affect the biosynthesis of secondary metabolites in the cells of green fruit. By briefly irradiating the harvested fruit of Capsicum annuum L. hot peppers with red light (RL, maximum 660 nm) and far-red light (FRL, maximum 730 nm) and by keeping them at a low temperature, we attempted to determine whether the state of phytochromes in fruit affects the biosynthesis of secondary metabolites. Using HPLC, we analysed the qualitative composition and quantitative content of the main carotenoids and alkaloids and the chlorophylls and ascorbate, in pepper fruit exposed to the above factors. We measured the parameters characterising the primary photochemical processes of photosynthesis and the transcript levels of genes encoding capsaicin biosynthesis enzymes. The total carotenoids content in the fruit increased most noticeably after 24 h of RL irradiation (more than 3.5 times compared to the initial value), and the most significant change in the composition of carotenoids occurred when the fruit was irradiated with FRL for 72 h. The capsaicin alkaloid content increased markedly after 72 h of FRL irradiation (more than 8 times compared to the initial value). It was suggested that decrease in the activity of phytochromes due to a low temperature or FRL may result in an increase in the expression of the PAL and CAM genes.

Feeding the world: impacts of elevated [CO2] on nutrient content of greenhouse grown fruit crops and options for future yield gains

Several long-term studies have provided strong support demonstrating that growing crops under elevated [CO2] can increase photosynthesis and result in an increase in yield, flavour and nutritional content (including but not limited to Vitamins C, E and pro-vitamin A). In the case of tomato, increases in yield by as much as 80% are observed when plants are cultivated at 1000 ppm [CO2], which is consistent with current commercial greenhouse production methods in the tomato fruit industry. These results provide a clear demonstration of the potential for elevating [CO2] for improving yield and quality in greenhouse crops. The major focus of this review is to bring together 50 years of observations evaluating the impact of elevated [CO2] on fruit yield and fruit nutritional quality. In the final section, we consider the need to engineer improvements to photosynthesis and nitrogen assimilation to allow plants to take greater advantage of elevated CO2 growth conditions.

Integrating Metabolomics and Proteomics Technologies Provides Insights into the Flavor Precursor Changes at Different Maturity Stages of Arabica Coffee Cherries

The metabolic modulation of major flavor precursors during coffee cherry ripening is critical for the characteristic coffee flavor formation. However, the formation mechanism of flavor precursors during coffee cherry ripening remains unknown. In the present study, a colorimeter was employed to distinguish different maturity stages of coffee cherry based on the coffee cherry skin colors, and proteomics and metabolomics profiles were integrated to comprehensively investigate the flavor precursor dynamics involved in Arabica coffee cherry ripening. The data obtained in the present study provide an integral view of the critical pathways involved in flavor precursor changes during coffee cherry ripening. Moreover, the contributions of critical events in regulating the development of flavor precursors during the four ripening stages of coffee cherries, including the biosynthesis and metabolism pathways of organic acids, amino acids, flavonoids, and sugars, are discussed. Overall, a total of 456 difference express metabolites were selected, and they were identified as being concentrated in the four maturity stages of coffee cherries; furthermore, 76 crucial enzymes from the biosynthesis and metabolism of sugars, organic acids, amino acids, and flavonoids contributed to flavor precursor formation. Among these enzymes, 45 difference express proteins that could regulate 40 primary amino acids and organic acids flavor precursors were confirmed. This confirmation indicates that the metabolic pathways of amino acids and organic acids played a significant role in the flavor formation of Arabica coffee cherries during ripening. These results provide new insights into the protease modulation of flavor precursor changes in Arabica coffee cherry ripening.

Recent Advances in Research into Jasmonate Biosynthesis and Signaling Pathways in Agricultural Crops and Products

Jasmonates (JAs) are phospholipid-derived hormones that regulate plant development and responses to environmental stress. The synthesis of JAs and the transduction of their signaling pathways are precisely regulated at multiple levels within and outside the nucleus as a result of a combination of genetic and epigenetic regulation. In this review, we focus on recent advances in the regulation of JA biosynthesis and their signaling pathways. The biosynthesis of JAs was found to be regulated with an autocatalytic amplification mechanism via the MYC2 regulation pathway and inhibited by an autonomous braking mechanism via the MYC2-targeting bHLH1 protein to terminate JA signals in a highly ordered manner. The biological functions of JAs mainly include the promotion of fruit ripening at the initial stage via ethylene-dependent and independent ways, the regulation of mature coloring via regulating the degradation of chlorophyll and the metabolism of anthocyanin, and the improvement of aroma components via the regulation of fatty acid and aldehyde alcohol metabolism in agricultural crops. JA signaling pathways also function in the enhancement of biotic and abiotic stress resistance via the regulation of secondary metabolism and the redox system, and they relieve cold damage to crops through improving the stability of the cell membrane. These recently published findings indicate that JAs are an important class of plant hormones necessary for regulating plant growth and development, ripening, and the resistance to stress in agricultural crops and products.

Biosynthesis of Chlorophyll and Other Isoprenoids in the Plastid of Red Grape Berry Skins

Despite current knowledge showing that fruits like tomato and grape berries accumulate different components of the light reactions and Calvin cycle, the role of green tissues in fruits is not yet fully understood. In mature tomato fruits, chlorophylls are degraded and replaced by carotenoids through the conversion of chloroplasts in chromoplasts, while in red grape berries, chloroplasts persist at maturity and chlorophylls are masked by anthocyanins. To study isoprenoid and lipid metabolism in grape skin chloroplasts, metabolites of enriched organelle fractions were analyzed by high-performance liquid chromatography-high-resolution mass spectrometry (HPLC-HRMS) and the expression of key genes was evaluated by real-time polymerase chain reaction (PCR) in berry skins and leaves. Overall, the results indicated that chloroplasts of the grape berry skins, as with leaf chloroplasts, share conserved mechanisms of synthesis (and degradation) of important components of the photosynthetic machinery. Some of these components, such as chlorophylls and their precursors, and catabolites, carotenoids, quinones, and lipids have important roles in grape and wine sensory characteristics.

Transcriptomic analysis of effects of 1-methylcyclopropene (1-MCP) and ethylene treatment on kiwifruit (Actinidia chinensis) ripening

Ethylene (ET) is a gaseous phytohormone with a crucial role in the ripening of many fruits, including kiwifruit (Actinidia spp.). Meanwhile, treatment with 1-methylcyclopropene (1-MCP), an artificial ET inhibitor delays the ripening of kiwifruit. The objective of this study was to determine the effect of ET and 1-MCP application during time-course storage of kiwifruit. In addition, we aimed to elucidate the molecular details underlying ET-mediated ripening process in kiwifruit. For this purpose, we conducted a time-course transcriptomic analysis to determine target genes of the ET-mediated maturation process in kiwifruit during storage. Thousands of genes were identified to be dynamically changed during storage and clustered into 20 groups based on the similarity of their expression patterns. Gene ontology analysis using the list of differentially expressed genes (DEGs) in 1-MCP-treated kiwifruit revealed that the identified DEGs were significantly enriched in the processes of photosynthesis metabolism and cell wall composition throughout the ripening process. Meanwhile, ET treatment rapidly triggered secondary metabolisms related to the ripening process, phenylpropanoid (e.g. lignin) metabolism, and the biosynthesis of amino acids (e.g. Phe, Cys) in kiwifruit. It was demonstrated that ET biosynthesis and signaling genes were oppositely affected by ET and 1-MCP treatment during ripening. Furthermore, we identified a ET transcription factor, AcEIL (Acc32482) which is oppositely responsive by ET and 1-MCP treatment during early ripening, potentially one of key signaling factor of ET- or 1-MCP-mediated physiological changes. Therefore, this transcriptomic study unveiled the molecular targets of ET and its antagonist, 1-MCP, in kiwifruit during ripening. Our results provide a useful foundation for understanding the molecular details underlying the ripening process in kiwifruit.

Multispectroscopic, virtual and in vivo insights into the photoaging defense mediated by the natural food colorant bixin

An upsurge in early onset of photoaging due to repeated skin exposure to environmental stressors such as UV radiation is a challenge for pharmaceutical and cosmeceutical divisions. Current reports indicate severe side effects because of chemical or synthetic inhibitors of matrix metalloproteases (MMPs) in anti-skin aging cosmeceuticals. We evaluated the adequacy of bixin, a well-known FDA certified food additive, as a scavenger of free radicals and its inhibitory mechanism of action on MMP1, collagenase, elastase, and hyaluronidase. The anti-skin aging potential of bixin was evaluated by several biotechnological tools in silico, in vitro and in vivo. Molecular docking and simulation dynamics studies gave a virtual insight into the robust binding interaction between bixin and skin aging-related enzymes. Absorbance and fluorescence studies, enzyme inhibition assays, enzyme kinetics and in vitro bioassays of human dermal fibroblast (HDF) cells highlighted bixin's role as a potent antioxidant and inhibitor of skin aging-related enzymes. Furthermore, in vivo protocols were carried out to study the impact of bixin administration on UVA induced photoaging in C57BL/6 mice skin. Here, we uncover the UVA shielding effect of bixin and its efficacy as a novel anti-photoaging agent. Furthermore, the findings of this study provide a strong foundation to explore the pharmaceutical applications of bixin in several other biochemical pathways linked to MMP1, collagenase, elastase, and hyaluronidase.

RNA-Seq and Iso-Seq Reveal the Important Role of COMT and CCoAOMT Genes in Accumulation of Scopoletin in Noni (Morinda citrifolia)

Scopoletin, the main component of clinical drugs and the functional component of health products, is highly abundant in noni fruit (Morinda citrifolia). Multiple enzyme genes regulate scopoletin accumulation. In the present study, differentially expressed genes of noni were analyzed by RNA sequencing (RNA-Seq) and the full-length genes by isoform-sequencing (Iso-Seq) to find the critical genes in the scopoletin accumulation mechanism pathway. A total of 32,682 full-length nonchimeric reads (FLNC) were obtained, out of which 16,620 non-redundant transcripts were validated. Based on KEGG (Kyoto Encyclopedia of Genes and Genomes) annotation and differential expression analysis, two differentially expressed genes, caffeic acid 3-O-methyltransferase (COMT) and caffeoyl-CoA O-methyltransferase (CCoAOMT), were found in the scopoletin accumulation pathway of noni. Real-time quantitative polymerase chain reaction (q-PCR), phylogenetic tree analysis, gene expression analysis, and the change in scopoletin content confirmed that these two proteins are important in this pathway. Based on these results, the current study supposed that COMT and CCoAOMT play a significant role in the accumulation of scopoletin in noni fruit, and COMT (gene number: gene 7446, gene 8422, and gene 6794) and CCoAOMT (gene number: gene 12,084) were more significant. These results provide the importance of COMT and CCoAOMT and a basis for further understanding the accumulation mechanism of scopoletin in noni.

Transcriptome analyses reveal the potential mechanisms for color changes of a sweet orange peel induced by Candidatus Liberibacter asiaticus

'Shatangju' mandarin (Citrus reticulate Blanco cv. Shatangju) is a Chinese citrus specialty in southern China with a delicious taste and an attractive appearance. Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus (CLas) threatens the Shatangju industry seriously. Fruits from citrus trees with HLB show 'red nose' peels with a serious reduction in fruit value. Differentially expressed genes (DEGs) have been identified in the leaves of several citrus species with HLB infection. However, similar studies on the fruit peels of citrus trees with HLB infection are very limited. In this study, the pathogen CLas was diagnosed in the 'red nose' fruit peels of Shatangju. The chlorophyll and carotenoid contents in different peels were also analyzed. Besides, we identified DEGs in the comparison between peels from normal red-colored and 'red nose' fruits via RNA-seq. A total of 1922 unigenes were identified as DEGs, of which 434 were up-regulated and 1488 were down-regulated in the 'red nose' fruit peels. DEGs involved in chlorophyll and carotenoids biosynthesis, photosynthesis, and transcription factors could be responsible for fruit color changes after HLB infection. Our findings provide a preliminary understanding of the mechanism underlying the formation of a 'red nose' on fruit peel from HLB-infected trees.

Fruit Development in Sweet Cherry

Fruits are an important source of vitamins, minerals and nutrients in the human diet. They also contain several compounds of nutraceutical importance that have significant antioxidant and anti-inflammatory roles, which can protect the consumer from diseases, such as cancer, and cardiovascular disease as well as having roles in reducing the build-up of LDL-cholesterol in blood plasma and generally reduce the risks of disease and age-related decline in health. Cherries contain high concentrations of bioactive compounds and minerals, including calcium, phosphorous, potassium and magnesium, and it is, therefore, unsurprising that cherry consumption has a positive impact on health. This review highlights the development of sweet cherry fruit, the health benefits of cherry consumption, and the options for increasing consumer acceptance and consumption.