Characterization of glucosinolates in 80 broccoli genotypes and different organs using UHPLC-Triple-TOF-MS method

Metabolome insights into nutrients and glucosinolates in broccoli and lacinato kale

To elucidate differences in nutritional components and glucosinolates between broccoli and lacinato kale leaves, and to promote consumption of broccoli and kale leaves for human nutrition, food development, and by-product utilisation, this study used UPLC-MS/MS and HPLC for both qualitative and quantitative analyses of their metabolome and glucosinolate profiles. In broccoli leaves, 11 glucosinolates were identified, notably including high concentrations of glucoraphanin, glucobrassicin, and neoglucobrassicin. In contrast, lacinato kale leaves contained seven glucosinolates, with glucoraphasatin being the most abundant. Moreover, our analysis revealed 644 metabolites, 87 of which were differentially expressed between these crucuiferous vegetables. These findings not only offer new insights into nutritional value but also highlight their potential as plant chassis for the biosynthesis of valuable products, thereby broadening food diversity and improving by-product utilisation.

Optimization of polyphenols extraction by deep eutectic solvent from broccoli stem and characterization of their composition and antioxidative effects

Broccoli stem is known to possess abundant polyphenols. To efficiently extract polyphenols from broccoli stems, we herein describe an updated deep eutectic solvent extraction (DESE) method. Response surface modeling was utilized for optimization of the DESE method, achieving the best yield of 5.10 ± 0.04 mg polyphenols/g broccoli stem powder under the following conditions: solvent, choline chloride-urea (molar ratio 1:3); extraction temperature, 80 °C; extraction duration, 55 min; water content, 60%; and liquid-solid ratio, 41:1 mL/g. Ultra Performance Liquid Chromatography-ElectrosprayIonization-Quadrupole Time-of-Flight/Mass Spectrometry (UPLC-ESI-QTOF/MS) was then employed for characterization of the main -composition, which revealed sinapinic acid (5.32%), trans-cinnamic acid (88.8%), quercetin (3.06%) and isochlorogenic acid (2.88%) as the dominant polyphenol compounds, and the extraction mechanism of the high efficiency of DES was dicussed. Moreover, the extracts from (ChCl-urea) DES exhibited remarkable antioxidant activity in vitro antioxidant test. These findings provide a viable and practical approach for broccoli culm polyphenol extraction and analysis, providing a methodological and knowledge basis for recycling broccoli wastes in an eco-friendly fashion.

Identification of volatile and flavor metabolites in three varieties of broccoli sprouts

Broccoli sprouts are promising functional food sources and their taste and flavor play a pivotal role in the acceptance of consumers. In this study, the flavor profiles of three varieties of broccoli sprouts, namely Bi Lv, You Xiu, and Lv Hua, were comprehensively characterized using HS-SPME-GC/MS analysis. A total of 364 volatile and flavor components across 15 chemical classes were successfully identified. The results revealed a majority of volatile metabolites exhibiting upregulation during the germination process, leading to an enhancement in taste intensity after germination, particularly for umami and sweet tastes, which was associated with an increase in associated amino acids and sugar content. Although the total glucosinolate content in broccoli sprouts has decreased compared to seeds, it remains the primary contributor to the bitterness of broccoli sprouts. The present study elaborated on the flavor contribution of broccoli sprouts, supporting the cultivation and consumption of them as a nutritious food.

Changes in Endogenous Carotenoids, Flavonoids, and Phenolics of Drought-Stressed Broccoli Seedlings After Ascorbic Acid Preconditioning

Drought is an abiotic disturbance that reduces photosynthesis, plant growth, and crop yield. Ascorbic acid (AsA) was utilized as a seed preconditioning agent to assist broccoli (Brassica oleracea var. italica) in resisting drought. However, the precise mechanism by which AsA improves seedlings' development remains unknown. One hypothesis is that AsA works via antioxidant mechanisms and reduces oxidative stress. This study aims to confirm the effect of varied concentrations of AsA (control, 0 ppm, 1 ppm, or 10 ppm) on seedling growth and changes in the antioxidant status of broccoli seedlings under regular watering or drought stress. AsA increased shoot dry mass, leaf area, net photosynthesis, and water use efficiency in watered and drought-stressed seedlings. AsA significantly (p < 0.001) increased carotenoid content in watered and drought-stressed seedlings by approximately 27% and 111%, respectively. Drought increased chlorophyll b, flavonoids, phenolics, ascorbate, and hydrogen peroxide production in control seedlings, but either had no effect or less effect on plants preconditioned with 10 ppm AsA. There was no improvement in reactive oxygen species scavenging in AsA-preconditioned seedlings compared to the control. The absence or reduction in biochemical indicators of stress suggests that preconditioned broccoli seedlings do not perceive stress the same as control seedlings. In conclusion, the consistent increase in carotenoid concentration suggests that carotenoids play some role in the preconditioning response, though the exact mechanism remains unknown.

Brassica oleracea var italica and Their By-Products as Source of Bioactive Compounds and Food Applications in Bakery Products

Broccoli (Brassica oleracea var. italica) is one of the most consumed cruciferous crops in the world, with China and Spain acting as the main producers from outside and within the EU, respectively. Broccoli florets are edible, while the leaves and stalks, discarded in the field and during processing, are by-products. Therefore, the objective of this study was to conduct a comprehensive review of the nutrient and phytochemical composition of broccoli and its by-products, as well as its beneficial effects. In addition, the study highlights the revalorization of broccoli by-products through innovative green technologies and explores their potential use in bakery products for the development of functional foods. The studies suggested that broccoli is characterized by a high content of nutrients and bioactive compounds, including vitamins, fiber, glucosinolates, and phenolic compounds, and their content varied with various parts. This high content of value-added compounds gives broccoli and its various parts beneficial properties, including anti-cancer, anti-inflammatory, antioxidant, antimicrobial, metabolic disorder regulatory, and neuroprotective effects. Furthermore, broccoli and its by-products can play a key role in food applications by improving the nutritional profile of products due to their rich content of bioactive compounds. As a result, it is essential to harness the potential of the broccoli and its by-products that are generated during its processing through an appropriate agro-industrial revalorization, using environmentally friendly techniques.

The Effects of Interventions with Glucosinolates and Their Metabolites in Cruciferous Vegetables on Inflammatory Bowel Disease: A Review

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract which affects millions of individuals worldwide. Despite advancements in treatment options, there is increasing interest in exploring natural interventions with minimal side effects. Cruciferous vegetables, such as broccoli, cabbage, and radishes, contain bioactive compounds known as glucosinolates (GLSs), which have shown promising effects in alleviating IBD symptoms. This review aims to provide a comprehensive overview of the physiological functions and mechanisms of cruciferous GLSs and their metabolites in the context of IBD. Reviewed studies demonstrated that GLSs attenuated all aspects of IBD, including regulating the intestinal microbiota composition, exerting antioxidant and anti-inflammatory effects, restoring intestinal barrier function, and regulating epigenetic mechanisms. In addition, a few interventions with GLS supplementation in clinical studies were also discussed. However, there are still several challenges and remaining knowledge gaps, including variations in animals' experimental outcomes, the bioavailability of certain compounds, and few clinical trials to validate their effectiveness in human subjects. Addressing these issues will contribute to a better understanding of the therapeutic potential of cruciferous GLSs and their metabolites in the management of IBD.

Glucosinolates and Their Hydrolytic Products-A Love Story of Environmental, Biological, and Chemical Conditions

BACKGROUND

Glucosinolates (GSL) play an important role in providing defense to plants and helping them to cope with various biotic, as well as abiotic, stresses. Many living beings including humans and animals, including some herbivores, have adapted themselves to use this defense mechanism for their own use. More than 120 glucosinolates are distributed within a large number of plants. Many factors are known to influence the GSL composition in a plant. Among these, cofactors, myrosinase isozymes, heavy metals and the environmental conditions such as light, CO2 and temperature are important in regulation. These factors ensure that different glucosinolate compositions can be produced by the plants, thus impacting the defense mechanism.

OBJECTIVE

The objective of the current review is to highlight the importance of the factors responsible for affecting glucosinolate composition and concentration.

METHODS

The review has been compiled using accessible literature from Pubmed, Scopus, and Google scholar. Efforts have been made to restrict the literature to the last 5 years (2018-2023), with some exceptions.

RESULTS

The current critical review acts as a resource for all the researchers working on these essential compounds. It provides information on the factors that may influence glucosinolate production. It also gives them an opportunity to modify the glucosinolate composition of a plant using the given information.

CONCLUSIONS

Glucosinolates have long been an ignored class of biomolecule. The plethora of biological activities of the compounds can be useful. Though there are some harmful components such as goitrin and progoitrin, these can be easily removed by modulating some of the factors highlighted in the review.

HIGHLIGHTS

The current review has covered most of the factors that have the ability to modify glucosinolate composition and concentration. The mechanistic action of these factors has also been discussed using the current available literature.

Transcriptome Analysis of Ethylene-Related Genes in Chlorine Dioxide-Treated Fresh-Cut Cauliflower

Chlorine dioxide (ClO2) is widely used for the quality preservation of postharvest horticultural plants. However, the molecular mechanism of how ClO2 works is not clear. The purpose of this study was to understand ethylene-related molecular signaling in ClO2-treated fresh-cut cauliflower florets. Transcriptome analysis was used to investigate ethylene-related gene regulation. A total of 182.83 Gb clean data were acquired, and the reads of each sample to the unique mapped position of the reference genome could reach more than 85.51%. A sum of 2875, 3500, 4582 and 1906 differential expressed genes (DEGs) were identified at 0 d, 4 d, 8 d and 16 d between the control group and ClO2-treated group, respectively. DEGs were enriched in functions such as 'response to oxygen-containing compounds' and 'phosphorylation', as well as MAPK signaling pathway, plant hormone transduction pathway and so on. Genes, including OXI1, MPK3, WRKY22 and ERF1, which are located at the junction of wounding, pathogen attack, pathogen infection or ethylene signal transduction pathways, were up-regulated in response to stress. ETR and CTR1 (both up-regulated), as well as three down-regulated genes, including BolC5t34953H (a probable NAC), BolC1t05767H (a probable NAC) and BolC2t06548H (a probable ERF13), might work as negative regulators for ethylene signal transduction. In conclusion, ethylene-related genes and pathways are involved in ClO2 treatment, which might enhance stress resistance and have a negative feedback mechanism.

The Anti-Inflammatory, Analgesic, and Antioxidant Effects of Polyphenols from Brassica oleracea var. capitata Extract on Induced Inflammation in Rodents

This study investigates the anti-inflammatory, analgesic, and antioxidant properties of polyphenols extracted from Brassica oleracea var. capitata (cabbage) ethanolic extract (BOE). Given the historical use of cabbage in traditional medicine for treating various ailments, this research aims to validate these effects scientifically. The study involved the characterization of BOE's bioactive compounds using Fourier Transform Infrared Spectroscopy (FTIR) and Liquid Chromatography-Diode Array Detection-Electro-Spray Ionization Mass Spectrometry (HPLC-DAD-ESI MS) analysis. We assessed the anti-inflammatory and analgesic effects of topical and oral BOE administration on rodent models with acute and subacute inflammation. Additionally, the antioxidant capacity of orally administered BOE was evaluated. The results showed that BOE possesses significant levels of phenolic compounds with a potent antioxidant activity. The topical administration of BOE demonstrated notable anti-inflammatory effects in the tested rodent models, which were comparable with nonsteroidal anti-inflammatory drugs. These findings suggest that BOE could be a valuable natural remedy for inflammation-related conditions, supporting its traditional uses and highlighting its potential for further pharmacological development.

The Effect of Broccoli Glucosinolates Hydrolysis Products on Botrytis cinerea: A Potential New Antifungal Agent

The present study investigates the interactions between eight glucosinolate hydrolysis products (GHPs) sourced from broccoli by-products and the detoxifying enzymes of Botrytis cinerea, namely eburicol 14-alpha-demethylase (CYP51) and glutathione-S-transferase (GST), through in silico analysis. Additionally, in vitro assays were conducted to explore the impact of these compounds on fungal growth. Our findings reveal that GHPs exhibit greater efficacy in inhibiting conidia germination compared to mycelium growth. Furthermore, the results demonstrate the antifungal activity of glucosinolate hydrolysis products derived from various parts of the broccoli plant, including inflorescences, leaves, and stems, against B. cinerea. Importantly, the results suggest that these hydrolysis products interact with the detoxifying enzymes of the fungus, potentially contributing to their antifungal properties. Extracts rich in GHPs, particularly iberin and indole-GHPs, derived from broccoli by-products emerge as promising candidates for biofungicidal applications, offering a sustainable and novel approach to plant protection by harnessing bioactive compounds from agricultural residues.

Chromosome-scale reference genome of broccoli (Brassica oleracea var. italica Plenck) provides insights into glucosinolate biosynthesis

Broccoli (Brassica oleracea var. italica Plenck) is an important vegetable crop, as it is rich in health-beneficial glucosinolates (GSLs). However, the genetic basis of the GSL diversity in Brassicaceae remains unclear. Here we report a chromosome-level genome assembly of broccoli generated using PacBio HiFi reads and Hi-C technology. The final genome assembly is 613.79 Mb in size, with a contig N50 of 14.70 Mb. The GSL profile and content analysis of different B. oleracea varieties, combined with a phylogenetic tree analysis, sequence alignment, and the construction of a 3D model of the methylthioalkylmalate synthase 1 (MAM1) protein, revealed that the gene copy number and amino acid sequence variation both contributed to the diversity of GSL biosynthesis in B. oleracea. The overexpression of BoMAM1 (BolI0108790) in broccoli resulted in high accumulation and a high ratio of C4-GSLs, demonstrating that BoMAM1 is the key enzyme in C4-GSL biosynthesis. These results provide valuable insights for future genetic studies and nutritive component applications of Brassica crops.

Variations of Major Glucosinolates in Diverse Chinese Cabbage (Brassica rapa ssp. pekinensis) Germplasm as Analyzed by UPLC-ESI-MS/MS

In this study, the variability of major glucosinolates in the leaf lamina of 134 Chinese cabbage accessions was investigated using Acquity ultra-performance liquid chromatography (UPLC-ESI-MS/MS). A total of twenty glucosinolates were profiled, of which glucobrassicanapin and gluconapin were identified as the predominant glucosinolates within the germplasm. These two glucosinolates had mean concentration levels above 1000.00 μmol/kg DW. Based on the principal component analysis, accessions IT186728, IT120044, IT221789, IT100417, IT278620, IT221754, and IT344740 were separated from the rest in the score plot. These accessions exhibited a higher content of total glucosinolates. Based on the VIP values, 13 compounds were identified as the most influential and responsible for variation in the germplasm. Sinigrin (r = 0.73), gluconapin (r = 0.78), glucobrassicanapin (r = 0.70), epiprogoitrin (r = 0.73), progoitrin (r = 0.74), and gluconasturtiin (r = 0.67) all exhibited a strong positive correlation with total glucosinolate at p < 0.001. This indicates that each of these compounds had a significant influence on the overall glucosinolate content of the various accessions. This study contributes valuable insights into the metabolic diversity of glucosinolates in Chinese cabbage, providing potential for breeding varieties tailored to consumer preferences and nutritional demands.

Recent advances in the contribution of glucosinolates degradation products to cruciferous foods odor: factors that influence degradation pathways and odor attributes

As one of the most important vegetables and oils consumed globally, cruciferous foods are appreciated for their high nutritional value. However, there is no comprehensive knowledge to sufficiently unravel the "flavor mystery" of cruciferous foods. The present review provides a comprehensive literature on the recent advances regarding the contribution of glucosinolates (GSL) degradation products to cruciferous foods odor, which focuses on key GSL degradation products contributing to distinct odor of cruciferous foods (Brassica oleracea, Brassica rapa, Brassica napus, Brassica juncea, Raphanus sativus), and key factors affecting GSL degradation pathways (i.e., enzyme-induced degradation, thermal-induced degradation, chemical-induced degradation, microwave-induced degradation) during different processing and cooking. A total of 93 volatile GSL degradation products (i.e., 36 nitriles, 33 isothiocyanates, 3 thiocyanates, 5 epithionitriles, and 16 sulfides) and 29 GSL (i.e., 20 aliphatic, 5 aromatic, and 4 indolic) were found in generalized cruciferous foods. Remarkably, cruciferous foods have a distinctive pungent, spicy, pickled, sulfur, and vegetable odor. In general, isothiocyanates are mostly present in enzyme-induced degradation of GSL and are therefore often enriched in fresh-cut or low-temperature, short-time cooked cruciferous foods. In contrast, nitriles are mainly derived from thermal-induced degradation of GSL, and are thus often enriched in high-temperature, long-time cooked cruciferous foods.

Simultaneous extraction and quantitative analysis of S-Methyl-l-Cysteine Sulfoxide, sulforaphane and glucosinolates in cruciferous vegetables by liquid chromatography mass spectrometry

Sulfur containing compounds including glucosinolates (GLS), sulforaphane (SFN) and S-methyl-l-cysteine sulfoxide (SMCSO) have been proposed to be partly responsible for the beneficial health effects of cruciferous vegetables. As such, greater understanding of their measurements within foods is important to estimate intake in humans and to inform dietary intervention studies. Herein is described a simple and sensitive method for simultaneous analysis of 20 GLS, SFN and SMCSO by liquid chromatography mass spectrometry. Analytes were effectively retained and resolved on an Xbridge C18 column. Detection can be achieved using high resolution or unit resolution mass spectrometry; the latter making the method more applicable to large studies. Quantitative analysis using calibration standards was demonstrated for 10 GLS, SFN and SMCSO. A further 10 GLS were tentatively identified using high resolution mass spectrometry. The use of surrogate GLS standards was shown to be unreliable, with closely related GLS displaying significantly different ionisation efficiencies.

Engineering Brassica Crops to Optimize Delivery of Bioactive Products Postcooking

Glucosinolates are plant-specialized metabolites that can be hydrolyzed by glycosyl hydrolases, called myrosinases, creating a variety of hydrolysis products that benefit human health. While cruciferous vegetables are a rich source of glucosinolates, they are often cooked before consumption, limiting the conversion of glucosinolates to hydrolysis products due to the denaturation of myrosinases. Here we screen a panel of glycosyl hydrolases for high thermostability and engineer the Brassica crop, broccoli (Brassica oleracea L.), for the improved conversion of glucosinolates to chemopreventive hydrolysis products. Our transgenic broccoli lines enabled glucosinolate hydrolysis to occur at higher cooking temperatures, 20 °C higher than in wild-type broccoli. The process of cooking fundamentally transforms the bioavailability of many health-relevant bioactive compounds in our diet. Our findings demonstrate the promise of leveraging genetic engineering to tailor crops with novel traits that cannot be achieved through conventional breeding and improve the nutritional properties of the plants we consume.

Broccoli, Amaranth, and Red Beet Microgreen Juices: The Influence of Cold-Pressing on the Phytochemical Composition and the Antioxidant and Sensory Properties

The aim of this study was to analyze in detail the phytochemical composition of amaranth (AMJ), red beet (RBJ), and broccoli (BCJ) microgreens and cold-pressed juices and to evaluate the antioxidant and sensory properties of the juices. The results showed the presence of various phenolic compounds in all samples, namely betalains in amaranth and red beet microgreens, while glucosinolates were only detected in broccoli microgreens. Phenolic acids and derivatives dominated in amaranth and broccoli microgreens, while apigenin C-glycosides were most abundant in red beet microgreens. Cold-pressing of microgreens into juice significantly altered the profiles of bioactive compounds. Various isothiocyanates were detected in BCJ, while more phenolic acid aglycones and their derivatives with organic acids (quinic acid and malic acid) were identified in all juices. Microgreen juices exhibited good antioxidant properties, especially ABTS•+ scavenging activity and ferric reducing antioxidant power. Microgreen juices had mild acidity, low sugar content, and good sensory acceptability and quality with the typical flavors of the respective microgreen species. Cold-pressed microgreen juices from AMJ, RBJ, and BCJ represent a rich source of bioactive compounds and can be characterized as novel functional products.

Application of Tryptophan and Methionine in Broccoli Seedlings Enhances Formation of Anticancer Compounds Sulforaphane and Indole-3-Carbinol and Promotes Growth

Broccoli is a popular cruciferous vegetable that is well known for its abundant health-promoting biochemicals. The most important of these beneficial biochemicals are glucosinolates, including glucoraphanin and glucobrassicin. Glucoraphanin and glucobrassicin can be broken down by myrosinases into sulforaphane and indole-3-carbinol, which have been demonstrated to have potent cancer-preventive properties. Efforts to increase glucoraphanin in broccoli seedlings have long been a focus; however, increasing glucoraphanin and glucobrassicin simultaneously, as well as enhancing myrosinase activity to release more sulforaphane and indole-3-carbinol, have yet to be investigated. This study aims to investigate the impact of the combined application of tryptophan and methionine on the accumulation of sulforaphane and indole-3-carbinol, as well as their precursors. Furthermore, we also examined whether this application has any effects on seedling growth and the presence of other beneficial compounds. We found that the application of methionine and tryptophan not only increased the glucoraphanin content by 2.37 times and the glucobrassicin content by 3.01 times, but that it also caused a higher myrosinase activity, resulting in a1.99 times increase in sulforaphane and a 3.05 times increase in indole-3-carbinol. In addition, better plant growth and an increase in amino acids and flavonoids were observed in broccoli seedlings with this application. In conclusion, the simultaneous application of tryptophan and methionine to broccoli seedlings can effectively enhance their health-promoting value and growth. Our study provides a cost-effective and multi-benefit strategy for improving the health value and yield of broccoli seedlings, benefiting both consumers and farmers.

Broccoli Cultivated with Deep Sea Water Mineral Fertilizer Enhances Anti-Cancer and Anti-Inflammatory Effects of AOM/DSS-Induced Colorectal Cancer in C57BL/6N Mice

This study aimed to determine the alleviating effect of broccoli grown with deep sea water mineral (DSWM) fertilizer extracted from deep sea water on the development of colorectal cancer in C57BL/6N mice treated with AOM/DSS. Naturaldream Fertilizer Broccoli (NFB) cultured with deep sea water minerals (DSWM) showed a higher antioxidant effect and mineral content. In addition, orally administered NFB, showed a level of recovery in the colon and spleen tissues of mice compared with those in normal mice through hematoxylin and eosin (H&E) staining. Orally administered NFB showed the inhibition of the expression of inflammatory cytokine factors IL-1β, IL-6, TNF, IFN-γ, and IL-12 while increasing the expression of IL-10. Furthermore, the expression of inflammatory cytokines and NF-κB in the liver tissue was inhibited, and that of inflammatory enzymes, such as COX-2 and iNOS, was reduced. In the colon tissue, the expression of p53 and p21 associated with cell cycle arrest increased, and that of Bcl-2 associated with apoptosis decreased. Additionally, the expression of Bax, Bad, Bim, Bak, caspase 9, and caspase 3 increased, indicating enhanced activation of apoptosis-related factors. These results demonstrate that oral administration of broccoli cultivated using DSWM significantly restores spleen and colon tissues and simultaneously inhibits the NF-κB pathway while significantly decreasing cytokine expression. Moreover, by inducing cell cycle arrest and activating cell apoptosis, they also suggest alleviating AOM/DSS-induced colon cancer symptoms in C57BL/6N mice.

Glucoraphanin Accumulation via Glucoraphanin Synthesis Promotion during Broccoli Germination

Glucoraphanin is an important glucosinolate which is widely distributed in Brassica vegetables and poses an anticancer effect to humans. Although researchers have paid a lot of attention to the changes in glucoraphanin concentration in seedlings of broccoli over 1-2 weeks, there has been little research focusing on the total whole-sprout glucoraphanin content within broccoli seedlings over 1-5 weeks. However, it is necessary to clarify the changes in total glucoraphanin content during the broccoli sprouting stage as broccoli seedlings are novel plant foods. This research explored glucoraphanin absolute accumulation and the biosynthesis mechanism in broccoli seedlings during a 5-week growth period. The results showed that glucoraphanin accumulation content was higher at week 4 than in the seeds. Moreover, the relative DL-methionine contents increased significantly after 3 weeks. Glucoraphanin synthetic gene expression levels were increased after 3 weeks, but the gene expressions of AOP3 (encoding 2-oxoglutarate-dependent dioxygenases) and MYR (encoding myrosinase) were significantly decreased. Furthermore, the 20 essential DEGs obtained can provide new insight into understanding the developmental regulation of broccoli seedlings. In addition, the results can also provide information on how to obtain higher glucoraphanin contents in broccoli sprouts.

Bioactives and Technological Quality of Functional Biscuits Containing Flour and Liquid Extracts from Broccoli By-Products

Broccoli by-products are an important source of health-promoting bioactive compounds, although they are generally underutilized. This study aimed to valorize non-compliant broccoli florets by transforming them into functional ingredients for biscuit formulation. A broccoli flour and three water/ethanol extracts (100:0, 75:25, 50:50; v/v) were obtained. The rheological properties and the content of bioactive compounds of the functional ingredients and biscuits were evaluated. The 50:50 hydroalcoholic extract was the richest in glucosinolates (9749 µg·g-1 DW); however, the addition of a small amount strongly affected dough workability. The enrichment with 10% broccoli flour resulted the best formulation in terms of workability and color compared to the other enriched biscuits. The food matrix also contributed to protecting bioactive compounds from thermal degradation, leading to the highest total glucosinolate (33 µg·g-1 DW), carotenoid (46 µg·g-1 DW), and phenol (1.9 mg GAE·g-1 DW) contents being present in the final biscuit. Therefore, broccoli flour is a promising ingredient for innovative healthy bakery goods. Hydroalcoholic extracts could be valuable ingredients for liquid or semi-solid food formulation.

Identification and Localization of Labile Molecules in Broccoli Cell by CLA-ICP-MS and Single-Cell Nanospray HRMS

Although molecular analysis and imaging by mass spectrometry are emerging as tools to identify metabolites and determine their distribution in cells and tissues, it is difficult to directly analyze the labile molecules at the single-cell level. Glucosinolate (GL) is a plant-active substance with much attention as a chemical defense mechanism known as a "mustard oil bomb" in broccoli. When tissue is damaged, these substances undergo rapid degradation, making them unsuitable for conventional mass spectrometry (MS), particularly for surface MS imaging analysis methods that necessitate intricate preprocessing. Herein, a strategy combining cryogenic laser ablation inductively coupled mass spectrometry (CLA-ICP-MS) and capillary microsampling nanospray high-resolution mass spectrometry (HRMS) was developed. The sulfur-rich microzone in tissue which was thought as a suspect GL-rich cell population was located via CLA-ICP-MS. Three GLs in single cells were accurately identified by nanospray HRMS with a hydrogen/deuterium exchange reaction. Subsequently, cell-by-cell imaging by nanospray HRMS showed that the GL-rich cells were below the stalk surface by approximately 30 μm. This proposed strategy can also be applied to rapidly identify labile compounds and localize molecule-rich cells in tissues.

Dynamic profiling of intact glucosinolates in radish by combining UHPLC-HRMS/MS and UHPLC-QqQ-MS/MS

Glucosinolates (GSLs) and their degradation products in radish confer plant defense, promote human health, and generate pungent flavor. However, the intact GSLs in radish have not been investigated comprehensively yet. Here, an accurate qualitative and quantitative analyses of 15 intact GSLs from radish, including four major GSLs of glucoraphasatin (GRH), glucoerucin (GER), glucoraphenin (GRE), and 4-methoxyglucobrassicin (4MGBS), were conducted using UHPLC-HRMS/MS in combination with UHPLC-QqQ-MS/MS. Simultaneously, three isomers of hexyl GSL, 3-methylpentyl GSL, and 4-methylpentyl GSL were identified in radish. The highest content of GSLs was up to 232.46 μmol/g DW at the 42 DAG stage in the 'SQY' taproot, with an approximately 184.49-fold increase compared to the lowest content in another sample. That the GSLs content in the taproots of two radishes fluctuated in a similar pattern throughout the five vegetative growth stages according to the metabolic profiling, whereas the GSLs content in the '55' leaf steadily decreased over the same period. Additionally, the proposed biosynthetic pathways of radish-specific GSLs were elucidated in this study. Our findings will provide an abundance of qualitative and quantitative data on intact GSLs, as well as a method for detecting GSLs, thus providing direction for the scientific progress and practical utilization of GSLs in radish.

Identification of glucosinolates and volatile odor compounds in microwaved radish (Raphanus sativus L.) seeds and the corresponding oils by UPLC-IMS-QTOF-MS and GC × GC-qMS analysis

The effect of microwave treatment on the content of glucosinolates (GSL) in radish seeds and volatile odor compounds in the microwaved radish seed oils (MRSO) is still unclear. In this study, a total of 13 GSL were identified and quantified in five radish seed varieties by UPLC-IMS-QTOF-MS, among which glucoraphenin, glucoraphasatin, glucoerucin accounting for up to 90 %. Total GSL decreased by 47.39-67.88% after microwave processing. Moreover, 58 odor compounds were identified in MRSO, including 6 sulfides, 12 nitriles, 2 isothiocyanates, 10 alcohols, 12 aldehydes, 5 ketones, 6 acids, and 5 others. The major odor compounds were (methyldisulfanyl)methane, dimethyltrisulfane, (methylsulfinyl)methane, 3-(methylsulfanyl)-1-propanol, methyl thiocyanate, hexanenitrile, 5-(methylsulfanyl)pentanenitrile, and 4-isothiocyanato-1-butene with odor activity value (OAV) higher than 1. The principal components analysis (PCA) results can distinguish MRSO from five different radish seed varieties, three of which (H20-18, H20-19 and H20-28) were in one group and other two (H20-23 and H20-26) were in another group. In addition, aliphatic GSL showed positive correlations with sulfides, isothiocyanates, and nitriles, while negative correlations with alcohols. This work provides a new insight into the odor contribution of GSL degradation products.

From farm to fork… and beyond! UV enhances Aryl hydrocarbon receptor-mediated activity of cruciferous vegetables in human intestinal cells upon colonic fermentation

While the "farm to fork" strategy ticks many boxes in the sustainability agenda, it does not go far enough in addressing how we can improve crop nutraceutical quality. Here, we explored whether supplementary ultraviolet (UV) radiation exposure during growth of broccoli and Chinese cabbage can induce bioactive tryptophan- and glucosinolate-specific metabolite accumulation thereby enhancing Aryl hydrocarbon receptor (AhR) activation in human intestinal cells. By combining metabolomics analysis of both plant extracts and in vitro human colonic fermentation extracts with AhR reporter cell assay, we reveal that human colonic fermentation of UVB-exposed Chinese cabbage led to enhanced AhR activation in human intestinal cells by 23% compared to plants grown without supplementary UV. Thus, by exploring aspects beyond "from farm to fork", our study highlights a new strategy to enhance nutraceutical quality of Brassicaceae, while also providing new insights into the effects of cruciferous vegetables on human intestinal health.

Age-specific allocation of glucosinolates within plant reproductive tissues

The Optimal Defense Theory (ODT) predicts that the distribution of defenses within a plant should mirror the value and vulnerability of each tissue. Although the ODT has received much experimental support, very few studies have examined defense allocation among reproductive tissues and none assessed simultaneously how these defenses evolve with age. We quantified glucosinolates in perianths, anthers and pistils at different bud maturity stages (i.e., intermediate flower buds, old flower buds and flowers) of undamaged and mechanically damaged plants of an annual brassicaceous species. The youngest leaf was used as a reference for vegetative organs, since it is predicted to be one of the most defended. In line with ODT predictions, reproductive tissues were more defended than vegetative tissues constitutively, and within the former, pistils and anthers more defended than perianths. No change in the overall defense level was found between bud maturity stages, but a significant temporal shift was observed between pistils and anthers. Contrary to ODT predictions, mechanical damage did not induce systemic defenses in leaves but only in pistils. Our results show that defense allocation in plant reproductive tissues occurs at fine spatial and temporal scales, extending the application framework of the ODT. They also demonstrate interactions between space and time in fine-scale defense allocation.

Research progress on the utilization technology of broccoli stalk, leaf resources, and the mechanism of action of its bioactive substances

Broccoli is a nutritious vegetable. It is high in protein, minerals, and vitamins. Also, it possesses antioxidant activities and is beneficial to the human body. Due to its active effect, broccoli is widely accepted by people in daily life. However, in terms of current utilization, only its florets are consumed as vegetables, while more than half of its stalks and leaves are not utilized. The stalks and leaves contain not only nutrients but also bioactive substances with physiologically regulating properties. Therefore research into the action and mechanism of its bioactive substances as well as its development and utilization technology will make contributions to the further promotion of its resource development and utilization. As a theoretical foundation for the resource utilization of broccoli stalks and leaves, this report will review the distribution and consumption of broccoli germplasm resources, the mechanism of action of bioactive substances, and innovative methods for their exploitation.

A highly efficient genetic transformation system for broccoli and subcellular localization

INTRODUCTION

Agrobacterium-mediated genetic transformation has been widely used for the identification of functional genes and regulatory and developmental mechanisms in plants. However, there are still some problems of low genetic transformation efficiency and high genotype dependence in cruciferous crops.

METHODS

In this study, broccoli, a worldwide Brassica crop, was used to investigate the effects of genotype, explant type, concentration of hygromycin B used during seedling selection, overexpression vector type, RNAi and CRISPR/cas9 on the genetic transformation efficiency. At the same time, two vectors, PHG-031350 and PHG-CRa, were used for subcellular localization of the glucoraphanin synthesis-related gene FMOGS-OX5 and clubroot resistance gene by a PEG-Ca2+-mediated transient transformation system for broccoli protoplasts. Finally, the Agrobacterium-mediated genetic transformation system of broccoli was optimized and improved.

RESULTS AND DISCUSSION

This study showed that hypocotyl explants are more suitable for Agrobacterium-mediated transgene and CRISPR/Cas9 gene editing of broccoli. In contrast to previous studies, we found that 5 mg/L hygromycin B was more advantageous for the selection of resistant broccoli sprouts, and genotype 19B42 reached the highest transformation rate of 26.96%, which is higher than that in Brassica oleracea crops. In addition, the inbred line 19B42 successfully achieved high genetic transformation of overexpression, RNAi and CRISPR/Cas9 vectors; thus, it is powerful recipient material for the genetic transformation of broccoli. Subcellular localization proved that the glucoraphanin metabolism-related gene Bol031350 and clubroot resistance gene CRa were both expressed in the cytoplasm and nucleus, which provided a scientific basis for studying the regulation of glucosinolate metabolism and clubroot resistance in cruciferous crops. Therefore, these findings will provide new insight into the improvement of the genetic transformation and molecular breeding of Brassica oleracea crops.

Genus Brassica By-Products Revalorization with Green Technologies to Fortify Innovative Foods: A Scoping Review

Food losses and waste reduction are a worldwide challenge involving governments, researchers, and food industries. Therefore, by-product revalorization and the use of key extracted biocompounds to fortify innovative foods seems an interesting challenge to afford. The aim of this review is to evaluate and elucidate the scientific evidence on the use of green technologies to extract bioactive compounds from Brassica by-products with potential application in developing new foods. Scopus was used to search for indexed studies in JCR-ISI journals, while books, reviews, and non-indexed JCR journals were excluded. Broccoli, kale, cauliflower, cabbage, mustard, and radish, among others, have been deeply reviewed. Ultrasound and microwave-assisted extraction have been mostly used, but there are relevant studies using enzymes, supercritical fluids, ultrafiltration, or pressurized liquids that report a great extraction effectiveness and efficiency. However, predictive models must be developed to optimize the extraction procedures. Extracted biocompounds can be used, free or encapsulated, to develop, reformulate, and/or fortify new foods as a good tool to enhance healthiness while preserving their quality (nutritional, functional, and sensory) and safety. In the age of recycling and energy saving, more studies must evaluate the efficiency of the processes, the cost, and the environmental impact leading to the production of new foods and the sustainable extraction of phytochemicals.

Comprehensive Evaluation of the Bioactive Composition and Neuroprotective and Antimicrobial Properties of Vacuum-Dried Broccoli (Brassica oleracea var. italica) Powder and Its Antioxidants

In this study, vacuum drying (VD) was employed as an approach to protect the bioactive components of and produce dried broccoli powders with a high biological activity. To achieve these goals, the effects of temperature (at the five levels of 50, 60, 70, 80 and 90 °C) and constant vacuum pressure (10 kPa) were evaluated. The results show that, with the increasing temperature, the drying time decreased. Based on the statistical tests, the Brunauer-Emmett-Teller (BET) model was found to fit well to sorption isotherms, whereas the Midilli and Kucuk model fit well to the drying kinetics. VD has a significant impact on several proximate composition values. As compared with the fresh sample, VD significantly reduced the total phenol, flavonoid and glucosinolate contents. However, it was shown that VD at higher temperatures (80 and 90 °C) contributed to a better antioxidant potential of broccoli powder. In contrast, 50 °C led to a better antimicrobial and neuroprotective effects, presumably due to the formation of isothiocyanate (ITC). Overall, this study demonstrates that VD is a promising technique for the development of extracts from broccoli powders that could be used as natural preservatives or as a neuroprotective agent.

Variation in glucosinolates and the formation of functional degradation products in two Brassica species during spontaneous fermentation

Vegetables from the Brassica species are excellent sources of glucosinolates (GLSs), the precursors of health-promoting isothiocyanates (ITCs). Fermentation enhances the biotransformation of GLSs into potential bioactive ITCs. To explore the biotransformation of GLSs during Brassica fermentation, the changes in GLSs during the fermentation of two Brassica species (i.e., cauliflower and broccoli); the formation of corresponding breakdown products; and the shifts in physicochemical parameters, bacterial communities, and myrosinase activities involved in GLSs degradation were systematically investigated. Nine aliphatic, three indolic, and two benzenic GLSs were identified in fermented cauliflower (FC) and fermented broccoli (FB). Aliphatic glucoiberin and glucoraphanin were the major forms of GLS in FC and FB, respectively; indolic glucobrassicin was also abundant in both FC and FB. The total GLS content decreased by 85.29% and 65.48% after 3 d of fermentation in FC and FB, respectively. After 2 d of fermentation, a significant increase in bioactive GLS degradation products (P < 0.05), including sulforaphane (SFN), iberin (IBN), 3,3-diindolylmethane (DIM), and ascorbigen (ARG), was observed in FC and FB compared to in fresh cauliflower and broccoli. Moreover, variations in pH value and titratable acidity in FC and FB correlated with Brassica fermentation and were accomplished by lactic acid bacteria, including Weissella, Lactobacillus-related genera, Leuconostoc, Lactococcus, and Streptococcus. These changes may enhance the biotransformation of GSLs to ITCs. Overall, our results indicate fermentation leads to the degradation of GLSs and the accumulation of functional degradation products in FC and FB.

A high-efficiency PEG-Ca2+-mediated transient transformation system for broccoli protoplasts

Transient transformation of plant protoplasts is an important method for studying gene function, subcellular localization and plant morphological development. In this study, an efficient transient transformation system was established by optimizing the plasmid concentration, PEG4000 mass concentration and genotype selection, key factors that affect transformation efficiency. Meanwhile, an efficient and universal broccoli protoplast isolation system was established. Using 0.5% (w/v) cellulase R-10 and 0.1% (w/v) pectolyase Y-23 to hydrolyze broccoli cotyledons of three different genotypes for 3 h, the yield was more than 5×10⁶/mL/g, and the viability was more than 95%, sufficient to meet the high standards for protoplasts to be used in various experiments. The average transformation efficiency of the two plasmid vectors PHG-eGFP and CP507-YFP in broccoli B1 protoplasts were 61.4% and 41.7%, respectively. Using this system, we successfully performed subcellular localization of the products of three target genes (the clubroot resistance gene CRa and two key genes regulated by glucosinolates, Bol029100 and Bol031350).The results showed that the products of all three genes were localized in the nucleus. The high-efficiency transient transformation system for broccoli protoplasts constructed in this study makes it possible to reliably acquire high-viability protoplasts in high yield. This research provides important technical support for international frontier research fields such as single-cell sequencing, spatial transcriptomics, plant somatic hybridization, gene function analysis and subcellular localization.

Identification and quantification of intact glucosinolates at different vegetative growth periods in Chinese cabbage cultivars by UHPLC-Q-TOF-MS

The aims of this study were to investigate glucosinolate variations in Chinese cabbage cultivars at different growth periods. Glucosinolates in two types of Chinese cabbage (Xiayangbai and Zaoshu-5) at different growth periods (seeds, germination, seedling, and rosette period) were investigated. Thirteen glucosinolates were identified and quantified using UHPLC-Q-TOF-MS. Concentrations of the glucosinolates were significantly different between Xiayangbai and Zaoshu-5. The seed period generated the highest concentration of glucosinolates, and aliphatic glucosinolate predominated in seeds, seedling, and leaves of the rosette as well as during germination. However, the dominant glucosinolate in the roots was an aromatic glucosinolate (gluconasturtiin). In addition, glucoerucin was only found in the roots of rosettes. There were positive significant correlations with each other among gluconapin, glucobrassicanapin, glucoraphanin, glucoalyssin, and 4-hydroxyglucobrassicin. Our results released the metabolism pathways of glucosinolates in Chinese cabbage, which provided scientific evidence to develop functional foods with higher glucosinolate.

Effects of nanocarbon solution treatment on the nutrients and glucosinolate metabolism in broccoli

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Nanocarbon application could enhance the total protein in broccoli, directly.

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18.75 L·ha⁻¹ nanocarbon solution greatly increase 22.9 % of glucoraphanin.

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Nanocarbon solution obviously reduces 4 indolic glucosinolate productions.

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Nanocarbon has great great impact on glucosinolate biosynthesis and pathway.

The effects of a nanocarbon solution on the nutrients, glucosinolate metabolism and glucoraphanin pathway in broccoli were investigated. Significant positive linear relationships were observed between the nanocarbon solution and total protein yield, although effects on the soluble sugars, vitamin C and dry matter production were not observed. All nanocarbon solutions significantly increased the glucoraphanin content (p < 0.05), and the 18.75 L·ha⁻¹ nanocarbon solution maximally increased the glucoraphanin content by 22.9 %. However, these treatments also significantly reduced the contents of glucobrassicin, 4-methoxyglucobrassicin, 4-hydroxyglucobrassicin and neoglucobrassicin. Further research demonstrated that the 18.75 L·ha⁻¹ nanocarbon solution significantly upregulated the MAM1, IPMI2, CYP79F1, FMOgs-ox2, AOP2, and TGG1 expression levels, which directly resulted in the accumulation of glucoraphanin and glucoerucin. This study provides insights into the prospective nanotechnological approaches for developing efficient and environmentally friendly nanocarbon solution for use on crops.

Germplasm Enhancement and Identification of Loci Conferring Resistance against Plasmodiophora brassicae in Broccoli

In order to breed broccoli and other Brassica materials to be highly resistant to clubroot disease, 41 Brassicaceae varieties were developed and identified between 2020 and 2021. Seven known clubroot genes were used for screening these materials. In addition, the resistant and susceptible broccoli cultivars were designed for observing their differences in the infection process with Plasmodiophora brassicae. The results showed that 90% of total materials had carried more than two clubroot resistance genes: one material carried two disease resistance genes, four materials carried seven genes for clubroot resistance, two materials carried six genes for clubroot resistance, and in total 32% of these materials carried five genes for clubroot resistance. As a result, several new genotypes of Brassicaceae germplasm were firstly created and obtained based on distant hybridization and identification of loci conferring resistance against Plasmodiophora brassicae in this study. We found and revealed that similar infection models of Plasmodiophora brassicae occurred in susceptible and resistant cultivars of broccoli, but differences in infection efficiency of Plasmodiophora brassicae also existed in both materials. For resistant broccoli plants, a small number of conidia formed in the root hair, and only a few spores could enter the cortex without forming sporangia while sporangia could form in susceptible plants. Our study could provide critical Brassica materials for breeding resistant varieties and new insight into understanding the mechanism of plant resistance.

Agri-Food Surplus, Waste and Loss as Sustainable Biobased Ingredients: A Review

Ensuring a sustainable supply of food for the world’s fast growing population is a major challenge in today’s economy, as modern lifestyle and increasing consumer concern with maintaining a balanced and nutritious diet is an important challenge for the agricultural sector worldwide. This market niche for healthier products, especially fruits and vegetables, has increased their production, consequently resulting in increased amounts of agri-food surplus, waste, and loss (SWL) generated during crop production, transportation, storage, and processing. Although many of these materials are not utilized, negatively affecting the environmental, economic, and social segments, they are a rich source of valuable compounds that could be used for different purposes, thus preventing the losses of natural resources and boosting a circular economy. This review aimed to give insights on the efficient management of agri-food SWL, considering conventional and emerging recovery and reuse techniques. Particularly, we explored and summarized the chemical composition of three worldwide cultivated and consumed vegetables (carrots, broccoli and lettuce) and evaluate the potential of their residues as a sustainable alternative for extracting value-added ingredients for the development of new biodynamic products.

Preharvest Methyl Jasmonate Treatment Increased Glucosinolate Biosynthesis, Sulforaphane Accumulation, and Antioxidant Activity of Broccoli

Broccoli is becoming increasingly popular among consumers owing to its nutritional value and rich bioactive compounds, such glucosinolates (GSLs) and hydrolysis products, which are secondary metabolites for plant defense, cancer prevention, and higher antioxidant activity for humans. In this study, 40 μmol/L methyl jasmonate (MeJA) was sprayed onto broccoli from budding until harvest. The harvested broccoli florets, stem, and leaves were used to measure the contents of GSLs, sulforaphane, total phenolics, and flavonoids, as well as myrosinase activity, antioxidant activity, and gene expression involved in GSL biosynthesis. The overall results revealed that GSL biosynthesis and sulforaphane accumulation were most likely induced by exogenous MeJA treatment by upregulating the expression of CYP83A1, SUR1, UGT74B1, and SOT18 genes. Exogenous MeJA treatment more remarkably contributed to the increased GSL biosynthesis in broccoli cultivars with low-level GSL content (Yanxiu) than that with high-level GSLs (Xianglv No.3). Moreover, MeJA treatment had a more remarkable increasing effect in broccoli florets than stem and leaves. Interestingly, total flavonoid content substantially increased in broccoli florets after MeJA treatment, but total phenolics did not. Similarly, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, trolox-equivalent antioxidant capacity (ABTS), and ferric-reducing antioxidant power (FRAP) were higher in broccoli floret after MeJA treatment. In conclusion, MeJA mediated bioactive compound metabolism, had positive effects on GSL biosynthesis, sulforaphane, and flavonoids accumulation, and showed positive correlation on inducing higher antioxidant activities in broccoli floret. Hence, preharvest supplementation with 40 μM MeJA could be a good way to improve the nutritional value of broccoli florets.

Variation in Glucosinolate Accumulation among Different Sprout and Seedling Stages of Broccoli (Brassica oleracea var. italica)

Glucosinolates (GLs) are plant secondary metabolites that may act against different types of cancers. Broccoli (Brassica oleracea var. italica) is rich in GLs which makes it an excellent source of these nutraceuticals. The composition and concentration of GLs vary among broccoli cultivars and throughout the developmental stages of the plant. To obtain the GL profiles of broccoli, GL compositions and contents in four early developmental stages (seeds, 3-day sprouts, 11-day and 17-day seedlings) were determined for nine cultivars of broccoli in this study. A total of 12 GLs including 9 aliphatic GLs and 3 indole GLs were identified from the nine broccoli cultivars using LC-QTOF-MS. UPLC results showed that aliphatic GLs concentrations decreased with broccoli sprouts and seedling growth for most cultivars. Interestingly, indole GLs amounts increased after germination and reached the highest level in 3-day sprouts or 11-day seedlings, and they fell back to a low level in 17-day seedlings. The GL profiles of nine cultivars documented in this study will provide useful information for high quality germplasm selection for cultivation or genetic engineering, and further understanding of the GL metabolic pathways.

Genetic Diversity and DNA Fingerprinting in Broccoli Carrying Multiple Clubroot Resistance Genes Based on SSR Markers

To identify cultivars quickly and accurately, DNA fingerprinting of 10 broccoli varieties was performed by using simple sequence repeat (SSR) marker technology. Highly informative and polymorphic SSR markers were screened using broccoli and rapeseed. Out of the 93 SSR marker pairs, 21 pairs were selected and found to have good polymorphism. Each marker pair generated 1 to 10 polymorphic bands with an average of 4.29. The average polymorphism information content (PIC) was 0.41 with a range from 0.16 to 0.95. Six selected marker pairs established the fingerprinting of the 10 accessions and their unique fingerprints. Cluster analysis of 10 accessions showed that the genetic similarity coefficient was between 0.57 and 0.91. They can be divided into 3 groups at the genetic similarity coefficient (GSC) of 0.73. The above results indicated that DNA fingerprinting could provide a scientific basis for the identification of broccoli polymerized multiple clubroot resistance genes. Research shows that SSR marker-based DNA fingerprinting further ensures plant seed purity.

Genome-Wide Association Study of Phenylalanine Derived Glucosinolates in Brassica rapa

Glucosinolates (GSLs) are sulfur-containing bioactive compounds usually present in Brassicaceae plants and are usually responsible for a pungent flavor and reduction of the nutritional values of seeds. Therefore, breeding rapeseed varieties with low GSL levels is an important breeding objective. Most GSLs in Brassica rapa are derived from methionine or tryptophan, but two are derived from phenylalanine, one directly (benzylGSL) and one after a round of chain elongation (phenethylGSL). In the present study, two phenylalanine (Phe)-derived GSLs (benzylGSL and phenethylGSL) were identified and quantified in seeds by liquid chromatography and mass spectrometry (LC-MS) analysis. Levels of benzylGSL were low but differed among investigated low and high GSL genotypes. Levels of phenethylGSL (also known as 2-phenylethylGSL) were high but did not differ among GSL genotypes. Subsequently, a genome-wide association study (GWAS) was conducted using 159 B. rapa accessions to demarcate candidate regions underlying 43 and 59 QTNs associated with benzylGSL and phenethylGSL that were distributed on 10 chromosomes and 9 scaffolds, explaining 0.56% to 70.86% of phenotypic variations, respectively. Furthermore, we find that 15 and 18 known or novel candidate genes were identified for the biosynthesis of benzylGSL and phenethylGSL, including known regulators of GSL biosynthesis, such as BrMYB34, BrMYB51, BrMYB28, BrMYB29 and BrMYB122, and novel regulators or structural genes, such as BrMYB44/BrMYB77 and BrMYB60 for benzylGSL and BrCYP79B2 for phenethylGSL. Finally, we investigate the expression profiles of the biosynthetic genes for two Phe-derived GSLs by transcriptomic analysis. Our findings provide new insight into the complex machinery of Phe-derived GSLs in seeds of B. rapa and help to improve the quality of Brassicaceae plant breeding.

Identification and Quantification of Glucosinolates and Phenolics in a Large Panel of Brassica napus Highlight Valuable Genetic Resources for Chemical Ecology and Breeding

Glucosinolate (GLS) and phenolic contents in Brassicaceae contribute to biotic and abiotic stress responses. Breeding crop accessions harboring agroecologically relevant metabolic profiles require a characterization of the chemical diversity in Brassica germplasm. This work investigates the diversity of specialized metabolites in 281 accessions of B. napus. First, an LC-HRMS2-based approach allowed the annotation of 32 phenolics and 36 GLSs, revealing 13 branched and linear alkyl-GLSs and 4 isomers of hydroxyphenylalkyl-GLSs, many of which have been rarely reported in Brassica. Then, quantitative UPLC-UV-MS-based profiling was performed in leaves and roots for the whole panel. This revealed striking variations in the content of 1-methylpropyl-GLS (glucocochlearin) and a large variation of tetra- and penta-glucosyl kaempferol derivatives among accessions. It also highlighted two main chemotypes related to sinapoyl-O-hexoside and kaempferol-O-trihexoside contents. By offering an unprecedented overview of the phytochemical diversity in B. napus, this work provides a useful resource for chemical ecology and breeding.

Exogenous Selenium Treatment Promotes Glucosinolate and Glucoraphanin Accumulation in Broccoli by Activating Their Biosynthesis and Transport Pathways

Supplementation using selenium (Se) on plants is an effective and widely used approach. It can not only be converted to more Se rich compounds but promote the accumulation of glucosinolates (GSLs) with anti-carcinogenic properties. However, the molecular mechanism of Se in regulating GSLs synthesis remains unclear. In the present study, we analyzed the effects of Se treatment (50 μM sodium selenite) on GSLs, glucoraphanin (4MSOB), and sulforaphane compounds in broccoli tissues. The transcript levels of genes involved in sulfur absorption and transport, GSLs biosynthesis, translocation, and degradation pathways were also evaluated. The study showed that Se treatment remarkably promoted the accumulation of total sulfur and total Se contents and increased Trp-derived GSLs levels in roots by 2 times. The 4MSOB concentration and sulforaphane content in fresh leaves was increased by 67% and 30% after Se treatment, respectively. For genes expressions, some genes involved in sulfate uptake and transporters, GSLs biosynthesis, and transporters were induced strongly upon Se exposure. Results revealed that exogenous Se treatment promotes the overaccumulation of GSLs and 4MSOB content in broccoli by activating the transcript levels of genes involved in sulfur absorption, GSLs biosynthesis, and translocation pathways.

Comparative study of the effects of selenium yeast and sodium selenite on selenium content and nutrient quality in broccoli florets (Brassica oleracea L. var. italica)

BACKGROUND

Approximately 0.5-1 billion people worldwide face the risk of selenium (Se) deficiency because of the low Se concentration in their diets. Broccoli can accumulate Se and comprises a source of daily Se supplement for humans. Se biofortification is an effective strategy for enhancing Se content in crops. In the present study, the effects of Se yeast and selenite application on the Se content and nutrient quality of broccoli were investigated.

RESULTS

Broccoli growth was promoted by Se yeast but inhibited by selenite. The total Se content of broccoli florets remarkably increased with increasing exogenous Se fertilizer concentrations. The main Se species in broccoli florets were methyl-selenocysteine and selenomethionine, and their contents were significantly higher under Se yeast treatments than under selenite treatments. Se(VI) was detected only under selenite treatments. Se yeast and selenite had different influences on soluble sugar, soluble protein, vitamin C and free amino acid contents in broccoli florets. The total phenolic acid and glucosinolate contents were substantially increased by Se yeast and selenite, although the total flavonoid content was reduced by Se yeast. Tests on antioxidant enzyme activities revealed that several antioxidant enzymes (catalase, peroxidase, superoxide dismutase and glutathione peroxidase) responded to Se yeast and selenite treatments.

CONCLUSION

Se yeast is preferred over selenite for maximizing Se uptake and nutrient accumulation in Se-rich broccoli cultivation. However, an extremely high Se content in broccoli florets cannot be directly consumed by humans, although they can be processed into Se supplements. © 2021 Society of Chemical Industry.

Electrophysiological, Morphologic, and Transcriptomic Profiling of the Ogura-CMS, DGMS and Maintainer Broccoli Lines

To better serve breeding of broccoli, the electrophysiological, morphological and transcriptomic profiling of the isogenic Ogura-CMS, DGMS and their maintainer fertile lines, were carried out by scanning electron microscopy, investigation of agronomic traits and RNA-sequencing analysis. The agronomic traits of plant height, length of the largest leaf, plant spread angle, single head weight, head width and stem diameter showed stronger performance in Ogura-CMS broccoli than in DGMS line or maintainer fertile line. However, the Ogura-CMS broccoli was poorer in the seed yield and seed germination than in the DGMS line and maintainer fertile line. Additionally, the DGMS broccoli had longer maturation and flowering periods than the Ogura-CMS and maintainer fertile lines. There were obvious differences in the honey gland, happening in the male sterility and fertile lines of broccoli. Additionally, the mechanism regulating Ogura-CMS and DGMS in broccoli was investigated using florets transcriptome analyses of the Ogura-CMS, DGMS and maintainer fertile lines. As a result, a total of 2670 differentially expressed genes (DEGs) were detected, including 1054 up- and 1616 downregulated genes in the Ogura-CMS and DGMS lines compared to the maintainer fertile line. A number of functionally known genes involved in plant hormones (auxin, salicylic acid and brassinosteroid), five Mitochondrial Oxidative Phosphorylation (OXPHOS) genes of atp8, LOC106319879, LOC106324734, LOC106314622 and LOC106298585, and three upregulated genes (Lhcb1, Lhcb3 and Lhcb5) associated with the photosynthesis-antenna protein pathway, were obviously detected to be highly associated with reproductive development including flowering time, maturity and reproductive period in the Ogura-CMS and DGMS broccoli comparing to their maintainer fertile line. Our research would provide a comprehensive foundation for understanding the differences of electrophysiological, morphological and transcriptomic profiles in the Ogura-CMS, DGMS and maintainer broccoli, and as well as being beneficial to exploring the mechanism of male sterility in Brassica crops.

Analysis of Glucosinolate Content and Metabolism Related Genes in Different Parts of Chinese Flowering Cabbage

Glucosinolates (GSLs) are important secondary metabolites that play important defensive roles in cruciferous plants. Chinese flowering cabbage, one of the most common vegetable crops, is rich in GSLs and thus has the potential to reduce the risk of cancer in humans. Many genes that are involved in GSL biosynthesis and metabolism have been identified in the model plant Arabidopsis thaliana; however, few studies investigated the genes related to GSL biosynthesis and metabolism in Chinese flowering cabbage. In the present study, the GSL composition and content in three different organs of Chinese flowering cabbage (leaf, stalk, and flower bud) were determined. Our results showed that the total GSL content in flower buds was significantly higher than in stalks and leaves, and aliphatic GSLs were the most abundant GSL type. To understand the molecular mechanisms underlying the variations of GSL content, we analyzed the expression of genes encoding enzymes involved in GSL biosynthesis and transport in different tissues of Chinese flowering cabbage using RNA sequencing; the expression levels of most genes were found to be consistent with the pattern of total GSL content. Correlation and consistency analysis of differentially expressed genes from different organs with the GSL content revealed that seven genes (Bra029966, Bra012640, Bra016787, Bra011761, Bra006830, Bra011759, and Bra029248) were positively correlated with GSL content. These findings provide a molecular basis for further elucidating GSL biosynthesis and transport in Chinese flowering cabbage.

Determination of 18 Intact Glucosinolates in Brassicaceae Vegetables by UHPLC-MS/MS: Comparing Tissue Disruption Methods for Sample Preparation

Glucosinolates (GSLs) are important precursor compounds with anticancer activities in Brassicaceae vegetables and are readily hydrolyzed by myrosinase. Given the diversity of these species, establishing an accurate and universal method to quantify intact GSLs in different plant tissues is necessary. Here, we compared and optimized three tissue disruption methods for sample preparation. After microwave treatment for 90 s, 13 GSLs in homogenized Chinese cabbage samples were recovered at 73–124%. However, a limitation of this method was that different tissues could not be processed under the same microwave conditions. Regarding universality, GSLs in Brassicaceae vegetables could be extracted from freeze-dried sample powder with 70% methanol (v/v) or frozen-fresh sample powder with 80% methanol (v/v). Moreover, heating extraction is necessary for GSLs extracted from frozen-fresh sample powder. Average recoveries of the two optimized methods were 74–119% with relative standard deviations ≤ 15%, with the limits of quantification 5.72–17.40 nmol/g dry weight and 0.80–1.43 nmol/g fresh weight, respectively. Notably, the method for analyzing intact GSLs was more efficient than that for desulfo-GSLs regarding operational complexity, detection speed and quantification accuracy. The developed method was applied to identify the characteristic GSLs in 15 Brassicaceae vegetables, providing a foundation for further research on GSLs.

New Vegetable Brassica Foods: A Promising Source of Bioactive Compounds

Brassica rapa is grown in northwestern Spain to obtain turnip greens. The tops of the same plants (flower stems with buds) are cut and sell as turnip tops, increasing the value of the crop. This practice could be extended to other brassicas. The objectives of this work are to study the phytochemical potential of tops of coles (Brassica oleracea) and leaf rape (Brassica napus) compared to turnip tops and to compare tops of different coles (cabbage, kale, tronchuda cabbage), which differ in their morphology and use. We evaluated the content of glucosinolates and phenolic compounds and the antioxidant capacity in leaves and tops of the three species. We found that tops had higher amount of glucosinolates than leaves. Phenolic content and antioxidant capacity followed the opposite trend. Therefore, consumption of leaves and tops are complementary, since both type of organs are enriched with different types of compound. Local varieties of kale, curly kale, cabbage and curly leave cabbage are interesting because of their GSLs and phenolic content and antioxidant capacity in both leaves and tops. From the human health perspective, tops of coles and leaf rape are interesting as new crops to include in the diet.