Carotenogenesis and chromoplast development during ripening of yellow, orange and red colored Physalis fruit

Application of benzothiadiazole to Cabernet Gernischt grapes (Vitis vinifera L.) for quality improvement: Effects on aroma metabolism precursors and related genes expression

Pre-harvest spraying of benzothiadiazole (BTH) can improve the winemaking properties of grapes, especially their aroma compounds and phenolics. Limited research has explored the molecular mechanisms by which BTH influences the accumulation of grape aroma precursors during early grape development. This study investigated the effects and putative molecular mechanisms of applying 0.37 mM BTH through whole-plant spraying on the accumulation of aroma metabolism precursors and gene expression in Cabernet Gernischt grapes during ripening. The results showed that BTH treatment increased the levels of fructose, alanine, aspartate, threonine, myristic acid, myristoleic acid, palmitic acid, β-cryptoxanthin, norisoprenoids and methoxypyrazines. Contrarily, it decreased the levels of glucose, sucrose, phenylalanine, tyrosine, leucine, valine, glycine, arginine, histidine, total unsaturated fatty acids (particularly linoleic acid), zeaxanthin, lutein, and organic acids. Additionally, BTH upregulated the expression of genes associated with the production and degradation of amino acids, fatty acids, and carotenoids while decreasing the expression of genes involved in the synthesis and degradation of soluble sugars and organic acids. Ten different metabolites, including fumaric acid, were identified as potential biological markers for distinguishing BTH-treated grapes from control grapes. The study demonstrates that BTH treatment had a substantial impact on the concentration and developmental patterns of aroma metabolism precursors. Furthermore, it altered the winemaking characteristics of Cabernet Gernischt grapes by modulating genes associated with the production and breakdown of metabolites.

Multi-omics analyses reveal the importance of chromoplast plastoglobules in carotenoid accumulation in citrus fruit

Chromoplasts act as a metabolic sink for carotenoids, in which plastoglobules serve as versatile lipoprotein particles. PGs in chloroplasts have been characterized. However, the features of PGs from non-photosynthetic plastids are poorly understood. We found that the development of chromoplast plastoglobules (CPGs) in globular and crystalloid chromoplasts of citrus is associated with alterations in carotenoid storage. Using Nycodenz density gradient ultracentrifugation, an efficient protocol for isolating highly purified CPGs from sweet orange (Citrus sinensis) pulp was established. Forty-four proteins were defined as likely comprise the core proteome of CPGs using comparative proteomics analysis. Lipidome analysis of different chromoplast microcompartments revealed that the nonpolar microenvironment within CPGs was modified by 35 triacylglycerides, two sitosterol esters, and one stigmasterol ester. Manipulation of the CPG-localized gene CsELT1 (esterase/lipase/thioesterase) in citrus calli resulted in increased lipids and carotenoids, which is further evidence that the nonpolar microenvironment of CPGs contributes to carotenoid accumulation and storage in the chromoplasts. This multi-feature analysis of CPGs sheds new light on the role of chromoplasts in carotenoid metabolism, paving the way for manipulating carotenoid content in citrus fruit and other crops.

Comparative transcriptomic and plastid development analysis sheds light on the differential carotenoid accumulation in kiwifruit flesh

Carotenoids are colorful lipophilic isoprenoids synthesized in all photosynthetic organisms which play roles in plant growth and development and provide numerous health benefits in the human diet (precursor of Vitamin A). The commercially popular kiwifruits are golden yellow-fleshed (Actinidia chinensis) and green fleshed (A. deliciosa) cultivars which have a high carotenoid concentration. Understanding the molecular mechanisms controlling the synthesis and sequestration of carotenoids in Actinidia species is key to increasing nutritional value of this crop via breeding. In this study we analyzed fruit with varying flesh color from three Actinidia species; orange-fleshed A. valvata (OF), yellow-fleshed A. polygama (YF) and green-fleshed A. arguta (GF). Microscopic analysis revealed that carotenoids accumulated in a crystalline form in YF and OF chromoplasts, with the size of crystals being bigger in OF compared to YF, which also contained globular substructures in the chromoplast. Metabolic profiles were investigated using ultra-performance liquid chromatography (UPLC), which showed that β-carotene was the predominant carotenoid in the OF and YF species, while lutein was the dominant carotenoid in the GF species. Global changes in gene expression were studied between OF and GF (both tetraploid) species using RNA-sequencing which showed higher expression levels of upstream carotenoid biosynthesis-related genes such as DXS, PSY, GGPPS, PDS, ZISO, and ZDS in OF species compared to GF. However, low expression of downstream pathway genes was observed in both species. Pathway regulatory genes (OR and OR-L), plastid morphology related genes (FIBRILLIN), chlorophyll degradation genes (SGR, SGR-L, RCCR, and NYC1) were upregulated in OF species compared to GF. This suggests chlorophyll degradation (primarily in the initial ripening stages) is accompanied by increased carotenoid production and localization in orange flesh tissue, a contrast from green flesh tissue. These results suggest a coordinated change in the carotenoid pathway, as well as changes in plastid type, are responsible for an orange phenotype in certain kiwifruit species.

Physalis pubescens L. branch and leaf extracts inhibit lymphoma proliferation by inducing apoptosis and cell cycle arrest

Physalis pubescens L. is an annual or perennial plant in the family Solanaceae It is used in traditional medicine for treating sore throats, coughs, urinary discomfort, and astringent pain, and externally for pemphigus and eczema in northern China. The proliferation inhibitory activity and mechanisms of the ethyl acetate extract (PHY-EA) from the leaves of Physalis pubescens were investigated. High performance liquid chromatography was used to identify the chemical composition of PHY-EA; sulforhodamine B was used to detect the proliferation inhibitory effect of PHY-EA on MCF-7, CA-46, Hela, HepG2, B16, and other tumor cells; flow cytometry was used to detect the effect of PHY-EA on the lymphoma cell cycle and apoptosis; Western blot was used to detect the expression of the cycle- and apoptosis-related proteins. The expression of Ki-67 and cleaved caspase 3 was detected by immunohistochemistry. The results showed that PHY-EA contained physalin B, physalin O, and physalin L. PHY-EA blocked the cell cycle of G2/M→G0/G1 in lymphoma cells and induced apoptosis in tumor cells. Mouse transplantation tumor experiments showed that PHY-EA had a significant inhibitory effect on mouse transplantation tumors, and the tumor volume and weight were significantly reduced. In conclusion, PHY-EA has a good antiproliferative effect on Burkkit lymphoma, indicating its potential medicinal value.

Reconstruction of the Native Biosynthetic System of Carotenoids in E. coli─Biosynthesis of a Series of Carotenoids Specific to Paprika Fruit

Capsanthin, capsorubin, cucurbitaxanthin A, and capsanthin 3,6-epoxide, a series of carotenoids specific to the red fruit of paprika (Capsicum annuum), were produced in pathway-engineered Escherichia coli cells. These cells functionally expressed multiple genes for eight carotenogenic enzymes, two of which, paprika capsanthin/capsorubin synthase (CaCCS) and zeaxanthin epoxidase (CaZEP), were designed to be located adjacently. The biosynthesis of these carotenoids, except for capsanthin, was the first successful attempt in E. coli. In a previous study, the levels of capsanthin synthesized were low despite the high expression of the CaCCS gene, which may have been due to the dual activity of CaCCS as a lycopene β-cyclase and CCS. An enhanced interaction between CaCCS and CaZEP that supplies antheraxanthin and violaxanthin, substrates for CaCCS, was considered to be crucial for an efficient reaction. To achieve this, we adapted S·tag and S-protein binding. The S·tag Thrombin Purification Kit (Novagen) is merchandized for in vitro affinity purification, and S·tag-fused proteins in the E. coli lysate are specifically trapped by S-proteins fixed on the agarose carrier. Furthermore, S-proteins have been reported to oligomerize via C-terminal swapping. In the present study, CaCCS and CaZEP were individually fused to the S·tag and designed to interact on oligomerized S-protein scaffolds in E. coli, which led to the biosynthesis of not only capsanthin and capsorubin but also cucurbitaxanthin A and capsanthin 3,6-epoxide. The latter reaction by CaCCS was assigned for the first time. This approach reinforces the scaffold's importance for multienzyme pathways when native biosynthetic systems are reconstructed in microorganisms.

Medicinal Plants in Peru as a Source of Immunomodulatory Drugs Potentially Useful Against COVID-19

The current COVID-19 pandemic, characterized by a highly contagious severe acute respiratory syndrome, led us to look for medicinal plants as an alternative to obtain new drugs, especially those with immunomodulatory abilities, capable of acting against the pulmonary infection caused by coronavirus 2 (SARS-CoV-2). Despite medical advances with COVID-19 drugs and vaccines, plant-based compounds could provide an array of suitable candidates to test against this virus, or at the very least, to alleviate some symptoms. Therefore, this review explores some plants widely used in Peru that show immunomodulatory properties or, even more, contain phytoconstituents potentially useful to prevent or alleviate the COVID-19 infection. More interestingly, the present review highlights relevant information from those plants to support the development of new drugs to boost the immune system. We used three criteria to choose nine vegetal species, and a descriptive search was then conducted from 1978 to 2021 on different databases, using keywords focused on the immune system that included information such as pharmacological properties, phytochemical, botanical, ethnobotanical uses, and some clinical trials. From these literature data, our results displayed considerable immunomodulation activity along with anti-inflammatory, antiviral, antioxidant, and antitumoral activities. Noticeably, these pharmacological activities are related with a wide variety of bioactive phytoconstituents (mixtures or isolated compounds) which may be beneficial in modulating the overt inflammatory response in severe COVID-19. Further scientific research on the pharmacological activities and clinical utilization of these potential plants are warranted.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-023-00367-w.

Plastid diversity and chromoplast biogenesis in differently coloured carrots: role of the DcOR3Leu gene

Distinct plastid types and ultrastructural changes are associated with differences in carotenoid pigment profiles in differently coloured carrots, and a variant of the OR gene, DcOR3^Leu is vital for chromoplast biogenesis. Accumulation of different types and amounts of carotenoids in carrots impart different colours to their taproots. In this study, the carotenoid pigment profiles, morphology, and ultrastructure of plastids in 25 carrot varieties with orange, red, yellow, or white taproots were investigated by ultra-high performance liquid chromatography as well as light and transmission electron microscopy. α-/β-Carotene and lycopene were identified as colour-determining carotenoids in orange and red carrots, respectively. In contrast, lutein was identified as the colour-determining carotenoid in almost all tested yellow and white carrots. The latter contained only trace amounts of lutein as a unique detectable carotenoid. Striking differences in plastid types that coincided with distinct carotenoid profiles were observed among the differently coloured carrots. Microscopic analysis of the different carotenoid pigment-loaded plastids revealed abundant crystalloid chromoplasts in the orange and red carrots, whereas amyloplasts were dominant in most of the yellow and white carrots, except for the yellow carrot 'Yellow Stone', where yellow chromoplasts were observed. Plastoglobuli and crystal remnants, the carotenoid sequestering substructures, were identified in crystalloid chromoplasts. Crystal remnants were often associated with a characteristic undulated internal membrane in orange carrots or several undulated membranes in red carrots. No crystal remnants, but some plastoglobuli, were observed in the plastids of all tested yellow and white carrots. In addition, the presence of chromoplast in carrot taproots was found to be associated with DcOR3^Leu, a natural variant of DcOR3, which was previously reported to be co-segregated with carotene content in carrots. Knocking out DcOR3^Leu in the orange carrot 'Kurodagosun' depressed chromoplast biogenesis and led to the generation of yellow carrots. Our results support that DcOR3^Leu is vital but insufficient for chromoplasts biogenesis in carrots, and add to the understanding of the formation of chromoplasts in carrots.

Plant carotenoids: recent advances and future perspectives

Carotenoids are isoprenoid metabolites synthesized de novo in all photosynthetic organisms. Carotenoids are essential for plants with diverse functions in photosynthesis, photoprotection, pigmentation, phytohormone synthesis, and signaling. They are also critically important for humans as precursors of vitamin A synthesis and as dietary antioxidants. The vital roles of carotenoids to plants and humans have prompted significant progress toward our understanding of carotenoid metabolism and regulation. New regulators and novel roles of carotenoid metabolites are continuously revealed. This review focuses on current status of carotenoid metabolism and highlights recent advances in comprehension of the intrinsic and multi-dimensional regulation of carotenoid accumulation. We also discuss the functional evolution of carotenoids, the agricultural and horticultural application, and some key areas for future research.

Fruit ripening: dynamics and integrated analysis of carotenoids and anthocyanins

BACKGROUND

Fruits are vital food resources as they are loaded with bioactive compounds varying with different stages of ripening. As the fruit ripens, a dynamic color change is observed from green to yellow to red due to the biosynthesis of pigments like chlorophyll, carotenoids, and anthocyanins. Apart from making the fruit attractive and being a visual indicator of the ripening status, pigments add value to a ripened fruit by making them a source of nutraceuticals and industrial products. As the fruit matures, it undergoes biochemical changes which alter the pigment composition of fruits.

RESULTS

The synthesis, degradation and retention pathways of fruit pigments are mediated by hormonal, genetic, and environmental factors. Manipulation of the underlying regulatory mechanisms during fruit ripening suggests ways to enhance the desired pigments in fruits by biotechnological interventions. Here we report, in-depth insight into the dynamics of a pigment change in ripening and the regulatory mechanisms in action.

CONCLUSIONS

This review emphasizes the role of pigments as an asset to a ripened fruit as they augment the nutritive value, antioxidant levels and the net carbon gain of fruits; pigments are a source for fruit biofortification have tremendous industrial value along with being a tool to predict the harvest. This report will be of great utility to the harvesters, traders, consumers, and natural product divisions to extract the leading nutraceutical and industrial potential of preferred pigments biosynthesized at different fruit ripening stages.

Quality of Physalis peruviana fruits coated with pectin and pectin reinforced with nanocellulose from P. peruviana calyces

Physalis peruviana is marketed without its calyx, which generates byproducts and a decrease in the shelf life of these fruits. The aim of this study was to evaluate the effect of edible pectin-coatings reinforced with nanocellulose from calyx on the physical-chemical and physiological parameters of P. peruviana fruits during refrigerated storage (5 °C) for ten days. The nanocellulose extraction was carried out using a combined extraction method (chemical procedures and ultrasound radiation). The characterization of the fibers showed that the maximum degradation temperatures ranged between 300 and 311 °C. The SEM analysis revealed the presence of fibers after the chemical treatment. The removal of lignin and hemicellulose was validated using Fourier Transform Infra Red (FTIR) spectroscopy. The results showed that the fruits treated with pectin and pectin reinforced with nanocellulose at 0.5 % (w/w) had an adequate visual appearance and showed a minor color change (ΔE of 19.04 and 21.04, respectively) and the highest retention of L∗ during storage. Although the addition of nanocellulose at 0.5% presented the lowest respiratory rate (29.60 mgCO₂/kg h), the treatment with pectin offered the least weight loss and showed the highest firmness retention at the end of storage. Thus, the edible pectin-coating may be useful for improving the postharvest quality and storage life of fresh P. peruviana fruit. Nanocellulose from P. peruviana calyces can be used under the concept of a circular economy; although, its use as a reinforcement of pectin showed some limitations.