Environmental and genetic effects on yield and secondary metabolite production in Brassica rapa crops

Adjustments of the Phytochemical Profile of Broccoli to Low and High Growing Temperatures: Implications for the Bioactivity of Its Extracts

Climate change causes shifts in temperature patterns, and plants adapt their chemical content in order to survive. We compared the effect of low (LT) and high (HT) growing temperatures on the phytochemical content of broccoli (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.) microgreens and the bioactivity of their extracts. Using different spectrophotometric, LC-MS/MS, GC-MS, and statistical methods, we found that LT increased the total phenolics and tannins in broccoli. The total glucosinolates were also increased by LT; however, they were decreased by HT. Soluble sugars, known osmoprotectants, were increased by both types of stress, considerably more by HT than LT, suggesting that HT causes a more intense osmotic imbalance. Both temperatures were detrimental for chlorophyll, with HT being more impactful than LT. HT increased hormone indole-3-acetic acid, implying an important role in broccoli's defense. Ferulic and sinapic acid showed a trade-off scheme: HT increased ferulic while LT increased sinapic acid. Both stresses decreased the potential of broccoli to act against H2O2 damage in mouse embryonal fibroblasts (MEF), human keratinocytes, and liver cancer cells. Among the tested cell types treated by H2O2, the most significant reduction in ROS (36.61%) was recorded in MEF cells treated with RT extracts. The potential of broccoli extracts to inhibit α-amylase increased following both temperature stresses; however, the inhibition of pancreatic lipase was increased by LT only. From the perspective of nutritional value, and based on the obtained results, we conclude that LT conditions result in more nutritious broccoli microgreens than HT.

Chemical Evaluation, In Vitro and In Vivo Anticancer Activity of Lavandula angustifolia Grown in Jordan

Lavandula angustifolia is the most widely cultivated Lavandula species for medicinal use. In this study, chemical and biological evaluation of L. angustifolia aqueous, methanol (MeOH), ethanol (EtOH), ethyl acetate (EtOAc), and chloroform (CHCl₃) extracts were conducted. Phytochemically, the extracts’ total phenol and flavonoid contents and their antioxidant potential were evaluated. Ethanol extract was analyzed by LC-MS. All extracts were screened in vitro for their antitumor potential using human breast cancer cell lines MCF-7 and MDA-MB-23. For the first time, the antiproliferative potential of the EtOH extract was tested in vivo using mice with induced breast cancer. Ethanol extract exhibited the best cytotoxicity and safety profile of the tested extracts, with IC₅₀ values of 104.1 µg/mL on MCF-7 and 214.5 µg/mL on MDA-MB-231 cell lines, respectively. In vivo, this extract revealed a reduction in tumor size by 43.29% in the treated group, compared to an increase in the tumor growth by 58.9% in the control group. Moreover, undetected tumor was found in 12.5% of the sample size. In conclusion, this study provides novel insight and evidence on the antiproliferative efficacy of L. angustifolia ethanol extract against breast cancer with potent anti-oxidant potential.

Further insight into decreases in seed glucosinolate content based on QTL mapping and RNA-seq in Brassica napus L

The QTL hotspots determining seed glucosinolate content instead of only four HAG1 loci and elucidation of a potential regulatory model for rapeseed SGC variation. Glucosinolates (GSLs) are amino acid-derived, sulfur-rich secondary metabolites that function as biopesticides and flavor compounds, but the high seed glucosinolate content (SGC) reduces seed quality for rapeseed meal. To dissect the genetic mechanism and further reduce SGC in rapeseed, QTL mapping was performed using an updated high-density genetic map based on a doubled haploid (DH) population derived from two parents that showed significant differences in SGC. In 15 environments, a total of 162 significant QTLs were identified for SGC and then integrated into 59 consensus QTLs, of which 32 were novel QTLs. Four QTL hotspot regions (QTL-HRs) for SGC variation were discovered on chromosomes A09, C02, C07 and C09, including seven major QTLs that have previously been reported and four novel major QTLs in addition to HAG1 loci. SGC was largely determined by superimposition of advantage allele in the four QTL-HRs. Important candidate genes directly related to GSL pathways were identified underlying the four QTL-HRs, including BnaC09.MYB28, BnaA09.APK1, BnaC09.SUR1 and BnaC02.GTR2a. Related differentially expressed candidates identified in the minor but environment stable QTLs indicated that sulfur assimilation plays an important rather than dominant role in SGC variation. A potential regulatory model for rapeseed SGC variation constructed by combining candidate GSL gene identification and differentially expressed gene analysis based on RNA-seq contributed to a better understanding of the GSL accumulation mechanism. This study provides insights to further understand the genetic regulatory mechanism of GSLs, as well as the potential loci and a new route to further diminish the SGC in rapeseed.

Benzoic Acid, Chlorine Dioxide, and 1-Methylcyclopropene Induce Flavonoid Metabolic Shifts in Postharvest Flowering Chinese Cabbage Revealed by High-Dimensional Analytical Data

Flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) is one of the most popular vegetables in China. However, the loss of the functional ingredients in postharvest flowering Chinese cabbage during storage is still serious, owing to the unclear causes of the metabolic shifts. Herein, benzoic acid, chlorine dioxide, and 1-methylcyclopropene (1-MCP) could maintain the quality of postharvest flowering Chinese cabbage, and 1-MCP showed the best effect. Furthermore, transcript-metabolite profiling of the treatments revealed a transcript-metabolite correlation network of the flavonoid biosynthesis pathways with a range of 3 to 3662 differentially expressed genes (DEGs) and a range of 23 to 37 differentially accumulated metabolites (DAMs). Surprisingly, 1-MCP had the best effect on shelf life among the treatments, although chlorine dioxide could stimulate the expression of four critical differential genes (Bra007142, Bra008792, Bra009358, and Bra027457) involved in delaying flavonoid degradation (hesperetin, chalcone, rutin, baicalein). As a result, our findings will help to improve our understanding of the regulation of flavonoid production in relation to the quality of postharvest flowering Chinese cabbage during storage.

Environmental Conditions and Agronomical Factors Influencing the Levels of Phytochemicals in Brassica Vegetables Responsible for Nutritional and Sensorial Properties

Recently, the consumption of healthy foods has been related to the prevention of cardiovascular, degenerative diseases and different forms of cancers, underlying the importance of the diet for the consumer’s health. Fruits and vegetables contain phytochemicals that act as protective factors for the human body, through different mechanisms of action. Among vegetables, Brassica received a lot of attention in the last years for the phytochemical compounds content and antioxidant capacity that confer nutraceutical value to the product. The amount of healthy bioactive compounds present in the Brassica defines the nutritional quality. These molecules could belong to the class of antioxidant compounds (e.g., phenols, vitamin C, etc.), or to non-antioxidant compounds (e.g., minerals, glucosinolates, etc.). The amount of these compounds in Brassica vegetables could be influenced by several factors, depending on the genotypes, the environmental conditions and the cultivation techniques adopted. The aim of this study is to highlight the main phytochemical compounds present in brassicas used as a food vegetable that confer nutritional and sensorial quality to the final product, and to investigate the main factors that affect the phytochemical concentration and the overall quality of Brassica vegetables.

Changes in Phenolics and Fatty Acids Composition and Related Gene Expression during the Development from Seed to Leaves of Three Cultivated Cardoon Genotypes

Cultivated cardoon (Cynara cardunculus var. altilis) has long been used as a food and medicine remedy and nowadays is considered a functional food. Its leaf bioactive compounds are mostly represented by chlorogenic acids and coumaroyl derivatives, known for their nutritional value and bioactivity. Having antioxidant and hepatoprotective properties, these molecules are used for medicinal purposes. Apart from the phenolic compounds in green tissues, cultivated cardoon is also used for the seed oil, having a composition suitable for the human diet, but also valuable as feedstock for the production of biofuel and biodegradable bioplastics. Given the wide spectrum of valuable cardoon molecules and their numerous industrial applications, a detailed characterization of different organs and tissues for their metabolic profiles as well as an extensive transcriptional analysis of associated key biosynthetic genes were performed to provide a deeper insight into metabolites biosynthesis and accumulation sites. This study aimed to provide a comprehensive analysis of the phenylpropanoids profile through UHPLC-Q-Orbitrap HRMS analysis, of fatty acids content through GC-MS analysis, along with quantitative transcriptional analyses by qRT-PCR of hydroxycinnamoyl-quinate transferase (HQT), stearic acid desaturase (SAD), and fatty acid desaturase (FAD) genes in seeds, hypocotyls, cotyledons and leaves of the cardoon genotypes “Spagnolo”, “Bianco Avorio”, and “Gigante”. Both oil yield and total phenols accumulation in all the tissues and organs indicated higher production in “Bianco Avorio” and “Spagnolo” than in “Gigante”. Antioxidant activity evaluation by DPPH, ABTS, and FRAP assays mirrored total phenols content. Overall, this study provides a detailed analysis of tissue composition of cardoon, enabling to elucidate value-added product accumulation and distribution during plant development and hence contributing to better address and optimize the sustainable use of this natural resource. Besides, our metabolic and transcriptional screening could be useful to guide the selection of superior genotypes.

Identification and quantitative analysis of phenolic glycosides with antioxidant activity in methanolic extract of Dendrobium catenatum flowers and selection of quality control herb-markers

Recently, the flowers of Dendrobium catenatum (D. officinale) have been approved as new food ingredient. This study aimed to investigate the herb-markers and their antioxidant activities in methanolic extracts of D. catenatum flowers, and to establish the quality evaluation methods for raw materials and their products of flower by HPLC. The methanolic extract of 11 strains of D. catenatum flowers were found to contain a high content of total phenol and flavonoids, and they possessed potential antioxidant capacities based on DPPH radical scavenging assay. A total of 21 phenolic herb-markers were selected according to the similarity and principal component analysis of the chromatographic fingerprinting profiles. Their structures were further elucidated by UV, HPLC-DAD-ESI-QTOF-MS/MS and NMR analyses. The identified compounds included 2 phenylpropanoids, 11C-glycosylflavones and 6 O-glycosylflavones, which could be employed as the indicators for quantitative evaluation of the quality and authenticity of the flowers. Based on the pre-column DPPH/ABTS⁺-HPLC analysis, the major compounds contributed to the antioxidative activity were identified as 1-O-caffeoyl-β-D-glucoside, rutin and isoquercitrin, all of which, were also the most abundant constituents in the methanolic extract. The results suggest the potential of D. catenatum flowers as a new antioxidant resources for medicinal and food products.

Brassica glucosinolate rhythmicity in response to light-dark entrainment cycles is cultivar-dependent

Coordination of plant circadian rhythms with the external environment provides growth and reproductive advantages to plants as well as enhanced resistance to insects and pathogens. Since glucosinolates (GLSs) play a major role as plant defensive compounds and could affect the palatability and health value of edible crops, the aim of this study was to investigate the species-specific patterns in circadian rhythmicity of these plant phytochemicals. Five different GLS-containing cultivars, from three Brassica crop species were studied. Plants were entrained to light-dark cycles (LD) for five weeks prior to release them into continuous light (LL). GLSs levels were monitored during five consecutive days (two days at LD conditions and three days at LL). The remaining plants were re-entrained to LD cycles (Re-LD plants) and GLS levels were studied as stated before during two consecutive days. Results showed that the period and amplitude of GLSs circadian outputs were cultivar-dependent. In addition, we assessed that the plant endogenous clock can be re-entrained for GLSs accumulation after a period of free-running conditions. Together, these data suggests that Brassica cultivars keep track the time of the day to coordinate their defenses. The demonstration of the cultivar-specific circadian effect on the GLSs levels in plants of different Brassica cultivars have the potential to identify new targets for improving cultivar phytochemicals using temporally informed approaches. In addition, provides an exceptional model to study the complexity of signal integration in plants.

QTL Mapping of Seed Glucosinolate Content Responsible for Environment in Brassica napus

Glucosinolates (GSLs) are a major class of secondary metabolites. The content of seed GSL is largely regulated by environments in rapeseed (Brassica napus). However, the genetic control of seed GSL content responsible for environment in B. napus has been poorly understood. In the current study, a doubled haploid (DH) population from a cross between winter and semi-winter lines of rapeseed was grown in two distinct eco-environments, Germany and China, to evaluate the eco-environment effect and dissect the quantitative trait loci (QTL) responsible for environment for seed GSL in rapeseed. The deviation value of GSL content between eco-environments (GSLE) was calculated for each line in the DH population and the QTLs for GSLE were detected. GSLE ranged from -46.90 to 36.13 μmol g^-1 meal in the DH population, suggesting the prominent eco-environmental effects for seed GSL in rapeseed. Four QTLs for GSLE were identified on chromosomes A04, A06, and A09 explaining 4.70∼9.93% of the phenotypic variation. Comparison of QTLs of seed GSL content between different eco-environments found three QTLs for GSL on A02 from 37.6 to 45.4 cM, A04 from 0 to 17.2 cM, and A09 from 67.0 to 98.6 cM exhibited significant difference of QTL effect between the German and Chinese eco-environments (P < 0.01), indicating the environment sensibility of these loci on seed GSL content. Moreover, flowering time (FT), an important environment adaptation trait in plant, was also investigated in this study. Comparative QTL analysis among GSLE, GSL, and FT revealed that three regions on chromosomes A02, A04, and A09 not only exhibited significant differences in QTL effect between Germany and China, but also co-located with the QTL intervals of GSLE and FT. Our results revealed that most of the GSL loci can influence GSL accumulation under different eco-environments, whereas the three QTL intervals on A02, A04, and A09 might be sensitive to the eco-environments for seed GSL content.

Effect of growth temperature on glucosinolate profiles in Arabidopsis thaliana accessions

Glucosinolates are plant secondary metabolites with important roles in plant defence against pathogens and pests and are also known for their health benefits. Understanding how environmental factors affect the level and composition of glucosinolates is therefore of importance in the perspective of climate change. In this study we analysed glucosinolates in Arabidopsis thaliana accessions when grown at constant standard (21 °C), moderate (15 °C) and low (9 °C) temperatures during three generations. In most of the tested accessions moderate and pronounced chilling temperatures led to higher levels of glucosinolates, especially aliphatic glucosinolates. Which temperature yielded the highest glucosinolate levels was accession-dependent. Transcriptional profiling revealed also accession-specific gene responses, but only a limited correlation between changes in glucosinolate-related gene expression and glucosinolate levels. Different growth temperatures in one generation did not consistently affect glucosinolate composition in subsequent generations, hence a clear transgenerational effect of temperature on glucosinolates was not observed.

Organ-Specific Quantitative Genetics and Candidate Genes of Phenylpropanoid Metabolism in Brassica oleracea

Phenolic compounds are proving to be increasingly important for human health and in crop development, defense and adaptation. In spite of the economical importance of Brassica crops in agriculture, the mechanisms involved in the biosynthesis of phenolic compounds presents in these species remain unknown. The genetic and metabolic basis of phenolics accumulation was dissected through analysis of total phenolics concentration and its individual components in leaves, flower buds, and seeds of a double haploid (DH) mapping population of Brassica oleracea. The quantitative trait loci (QTL) that had an effect on phenolics concentration in each organ were integrated, resulting in 33 consensus QTLs controlling phenolics traits. Most of the studied compounds had organ-specific genomic regulation. Moreover, this information allowed us to propose candidate genes and to predict the function of genes underlying the QTL. A number of previously unknown potential regulatory regions involved in phenylpropanoid metabolism were identified and this study illustrates how plant ontogeny can affect a biochemical pathway.

Evolution of ellagitannin content and profile during fruit ripening in Fragaria spp

Ellagitannins and ellagic acid conjugates are polyphenols present in the human diet, in particular strawberries (Fragaria spp.). The first aim of this study was isolation and structural characterization of casuarictin and 3-O-methyl ellagic acid 3'-O-α-rhamnopyranoside, which were found to be abundant in Fragaria spp., along with agrimoniin. The second aim was accurate profiling and quantification of 26 ellagitannins and ellagic acid conjugates in six Fragaria x ananassa cultivars and two Fragaria vesca species. The third aim was to describe the ellagitannins behavior during fruit ripening from the green stage to over-ripeness. It was shown that there are major qualitative and quantitative differences in the amount and profile of ellagitannins and ellagic acid conjugates between Fragaria spp. Genotype is a major factor in defining ellagitannin concentration and patterns between strawberries, and variable behavior of the genotypes was observed, in the context of a significant drop in ellagitannins during ripening.