Glucosinolate Profiles Research Articles

Growth and glucosinolate profiles of a common Asian green leafy vegetable, Brassica rapa subsp. chinensis var. parachinensis (choy sum), under LED lighting

Technological advancements in light-emitting diode (LED) technology have led to the production, under controlled indoor conditions, of value-added crops that are high in nutritional or nutraceutical contents. In this study, the growth and glucosinolate (GSL) profiles of a common Asian vegetable, Brassica rapa subsp. chinensis var. parachinensis (choy sum or cai xin) were determined under LED lighting. The growth of choy sum was influenced by both the LED light intensity and spectrum, with plants grown under 160 μmol m−2 s−1 red-blue light (160RB) producing the highest shoot biomass (∼100–300 % increment in adult plants). GSL content was found to vary across growth stages regardless of LED treatment. Total GSLs per gram fresh weight were four times higher in one-leafed seedlings than in adult plants. A shift from a high proportion of aliphatic GSLs in one-leafed seedlings to indolic and aromatic GSLs in three-leafed seedlings and adult plants was attributed to an increase in the proportion of glucobrassicin and/or 4-hydroxy-glucobrassicin, and gluconasturtiin which are known to have anti-cancer properties. Our results will be useful for the production of GSL-enhanced vegetables through urban farming.

Natural Variation of Glucosinolates and Their Breakdown Products in Broccoli (Brassica oleracea var. italica) Seeds.

Seeds of 32 pure lines and 6 commercial broccoli cultivars were used to investigate variation in glucosinolates and their breakdown products. The aliphatic glucosinolate content was 54.5-218.7 μmol/g fresh weight, accounting for >90% of the total glucosinolates. The major glucosinolates found were glucoraphanin and glucoerucin in 27 samples and progoitrin in 7 samples. A gas chromatography-flame ionization detector (GC-FID) method was used to identify glucosinolate breakdown products; nine products were directly determined using standards. Using Arabidopsis thaliana lines myb28myb29 and Landsberg erecta to hydrolyze each reference glucosinolate, seven products were tentatively identified. 4-(Methylsulfinyl)butyl isothiocyanate and 5-(methylsulfinyl)pentanenitrile contents were 2.6-91.1 μmol/g fresh weight and 0-35.4 μmol/g fresh weight, respectively, with epithionitriles being more common than nitriles in accessions rich in alkenyl glucosinolate. Additionally, (S)-5-vinyl-1,3-oxazolidine-2-thione was detected in accessions rich in progoitrin. Specific lines with altered glucosinolate profiles and breakdown products were obtained and discussed according to the putative glucosinolate metabolism pathway.

Selenium Application During Radish (Raphanus sativus) Plant Development Alters Glucosinolate Metabolic Gene Expression and Results in the Production of 4-(methylseleno)but-3-enyl glucosinolate.

Selenium (Se) is an essential micronutrient for human health, entering the diet mainly through the consumption of plant material. Members of the Brassicaceae are Se-accumulators that can accumulate up to 1g Se kg−1 dry weight (DW) from the environment without apparent ill effect. The Brassicaceae also produce glucosinolates (GSLs), sulfur (S)-rich compounds that benefit human health. Radish (Raphanus sativus) has a unique GSL profile and is a Se-accumulating species that is part of the human diet as sprouts, greens and roots. In this report we describe the effects of Se-fertilisation on GSL production in radish during five stages of early development (from seed to mature salad greens) and on the transcript abundance of eight genes encoding enzymes involved in GSL metabolism. We tentatively identified (by tandem mass spectrometry) the selenium-containing glucosinolate, 4-(methylseleno)but-3-enyl glucosinolate, with the double bond geometry not resolved. Two related isothiocyanates were tentatively identified by Gas Chromatography-Mass Spectrometry as (E/Z?) isomers of 4-(methylseleno)but-3-enyl isothiocyanate. Se fertilisation of mature radish led to the presence of selenoglucosinolates in the seed. While GSL concentration generally reduced during radish development, GSL content was generally not affected by Se fertilisation, aside from the indole GSL, indol-3-ylmethyl glucosinolate, which increased on Se treatment, and the Se-GSLs, which significantly increased during development. The transcript abundance of genes involved in aliphatic GSL biosynthesis declined with Se treatment while that of genes involved in indole GSL biosynthesis tended to increase. APS kinase transcript abundance increased significantly in three of the four developmental stages following Se treatment. The remaining genes investigated were not significantly changed following Se treatment. We hypothesise that increased APS kinase expression in response to Se treatment is part of a general protection mechanism controlling the uptake of S and the production of S-containing compounds such as GSLs. The upregulation of genes encoding enzymes involved in indole GSL biosynthesis and a decrease in those involved in aliphatic GSL biosynthesis may be part of a similar mechanism protecting the plant’s GSL complement whilst limiting the amount of Se-GSLs produced.

Comparative study of the glucosinolate profiles in turnip from four agroclimatic zones of china and neighboring countries

Turnip (Brassica rapa) is an important crop cultivated all over the world. Glucosinolates as the characteristic constituents showed diverse bioactivities, especially for their anti-cancer and hepatoprotective effects. Plenty of investigation has revealed the glucosinolate contents and profiles in various Brassica vegetables (mainly on aerial parts), whereas their detailed comparison between different agroclimatic zones is rarely reported. This study aimed to make a comparison on the total glucosinolate contents (TGCs) and chemical profiles in 59 turnip landraces. The turnip tubers were obtained by collecting the seeds from four agroclimatic zones, Yunnan, Himalayas, Qinghai-Tibetan Plateau (QTP) and Xinjiang, around southwest China and sown in Jianshui County. The TGCs in turnip were high (TGCYunnan = 0.463 ± 0.020 mg g−1 d.w., TGCHimalaya = 0.498 ± 0.019 mg g−1 d.w.) in the middle elevation environments, and decreased in both lower elevation (TGCXinjiang = 0.273 ± 0.014 mg g−1 d.w.) and higher elevation (TGCQTP = 0.346 ± 0.021 mg g−1 d.w.) environments, which followed a hump-shaped pattern along the altitudinal gradient. According to the principal component analysis, the 59 investigated landraces were dissected into two clusters, Yunnan-Himalaya environment and Xinjiang-Qinghai Tibetan Plateau environment. Significant correlation was observed between the aboveground biomass and underground biomass (r = 0.653, p < 0.01), leaf length and tuber diameter (r = 0.448, p < 0.01), whereas the TGCs were neither correlated with the aboveground nor the underground biomass. A total of 18 constituents involving ten glucosinolates, three phenylpropanoids, one lignan and four sulfur compounds were characterized based on their MS/MS fragmentation and UV absorption. Gluconasturtiin (7) and glucobrassicanapin (4) were revealed as the main glucosinolates in turnip. The TGCs in turnip varied significantly (one sample t (297) = 34.859, P = 0.00) with different climatic zones, of which warm and humid climate [e.g. Yunnan and Himalaya areas (TGCwarm and humid = 0.467 ± 0.014 mg g−1 d.w.)] is profitable for the accumulation of glucosinolates, as compared to the arid and stressful environment [e.g. QTP and Xinjiang areas (TGCarid and stressful = 0.329 ± 0.014 mg g−1 d.w.)]. This investigation suggested that the glucosinolate profiles were closely related to the genes involved in regulating glucosinolate biosynthesis, herbivore pressure and vegetative growth.

Induced production of indol-3-ylmethyl glucosinolates in hairy roots of Chinese cabbage (Brassica rapa subsp. pekinensis): perspectives to enhance the content of bioactive compounds

Brassica species have an important class of secondary metabolites, the glucosinolates, whose specific hydrolysis products are critical for flavor, smell and nutritional properties. While some of the hydrolysis products have been recognized as health promoting compounds for humans, others, such as indol-3-ylmethyl glucosinolates, have been associated with deleterious effects by forming DNA adducts. Thus, it is important to have a strong knowledge of all aspects involved in the biosynthesis of such compounds in order to design vegetables with an improved secondary metabolite profile. In this context we present this study, in which Chinese cabbage was treated with different signaling substances (jasmonic acid, salicylic acid, and yeast extract) and grown for 4 weeks, under light, 8°C and 37°C. Metabolomics analysis, aiming at specific changes in the glucosinolate and related indole derivatives profile and content, were performed using HPLC-DAD-UV/VIS. Hairy roots of Chinese cabbage were studied. Preliminary results showed a variation in the profile and content of the above compounds, suggesting a variation in their biosynthetic pathway. The specific differences observed in this comparative analysis enables the development of new and innovative tools for breeding vegetables with improved GS and indole compounds in the near future.

Glucosinolates of Lepidium graminifolium L. (Brassicaceae) from Croatia

The glucosinolate (GSL) profiles (inflorescence, stem, root, and fruit) of the wild-growing plant Lepidium graminifolium L. (Brassicaceae) from Croatia was established by LC-MS analysis. During this investigation, we confirmed the presence of benzyl- (1), 3-methoxybenzyl- (2), 4-hydroxybenzyl- (4), 4-methoxyindol-3-ylmethyl- (7) GSLs and reported for the first time in the plant the presence of (2 R)-hydroxybut-3-enyl- (11), (2S)-hydroxybut-3-enyl- (12), but-3-enyl- (13), and 2-phenylethyl- (14) GSLs. Finally, 3-hydroxybenzyl GSL (3) was isolated for the first time from L. graminifolium inflorescence and characterised by spectroscopic data interpretation.

Glucosinolate variability between turnip organs during development.

Turnip (Brassica rapa spp. rapa) is an important vegetable species, with a unique physiology. Several plant parts, including both the turnip tubers and leaves, are important for human consumption. During the development of turnip plants, the leaves function as metabolic source tissues, while the tuber first functions as a sink, while later the tuber turns into a source for development of flowers and seeds. In the present study, chemical changes were determined for two genotypes with different genetic background, and included seedling, young leaves, mature leaves, tuber surface, tuber core, stalk, flower and seed tissues, at seven different time points during plant development. As a basis for understanding changes in glucosinolates during plant development, the profile of glucosinolates was analysed using liquid chromatography (LC) coupled to mass spectrometry (MS). This analysis was complemented by a gene expression analysis, focussed on GLS biosynthesis, which could explain part of the observed variation, pointing to important roles of specific gene orthologues for defining the chemical differences. Substantial differences in glucosinolate profiles were observed between above-ground tissues and turnip tuber, reflecting the differences in physiological role. In addition, differences between the two genotypes and between tissues that were harvested early or late during the plant lifecycle. The importance of the observed differences in glucosinolate profile for the ecophysiology of the turnip and for breeding turnips with optimal chemical profiles is discussed.

Differential regulation of host plant adaptive genes in Pieris butterflies exposed to a range of glucosinolate profiles in their host plants

Specialist herbivores have often evolved highly sophisticated mechanisms to counteract defenses mediated by major plant secondary-metabolites. Plant species of the herbivore host range often display high chemical diversity and it is not well understood how specialist herbivores respond to this chemical diversity. Pieris larvae overcome toxic products from glucosinolate hydrolysis, the major chemical defense of their Brassicaceae hosts, by expressing nitrile-specifier proteins (NSP) in their gut. Furthermore, Pieris butterflies possess so-called major allergen (MA) proteins, which are multi-domain variants of a single domain major allergen (SDMA) protein expressed in the guts of Lepidopteran larvae. Here we show that Pieris larvae fine-tune NSP and MA gene expression depending on the glucosinolate profiles of their Brassicaceae hosts. Although the role of MA is not yet fully understood, the expression levels of NSP and MA in larvae that fed on plants whose glucosinolate composition varied was dramatically changed, whereas levels of SDMA expression remained unchanged. In addition, we found a similar regulation pattern among these genes in larvae feeding on Arabidopsis mutants with different glucosinolate profiles. Our results demonstrate that Pieris larvae appear to use different host plant adaptive genes to overcome a wide range of glucosinolate profiles in their host plants.

Interspecific Differences in the Larval Performance of Pieris Butterflies (Lepidoptera: Pieridae) Are Associated with Differences in the Glucosinolate Profiles of Host Plants.

The tremendous diversity of plants and herbivores has arisen from a coevolutionary relationship characterized by plant defense and herbivore counter adaptation. Pierid butterfly species feed on Brassicales plants that produce glucosinolates as a chemical deterrent against herbivory. In turn, the larvae of pierids have nitrile specifier proteins (NSPs) that are expressed in their gut and disarm glucosinolates. Pierid butterflies are known to have diversified in response to glucosinolate diversification in Brassicales. Therefore, each pierid species is expected to have a spectrum of host plants characterized by specific glucosinolate profiles. In this study, we tested whether the larval performance of different Pieris species, a genus in Pieridae (Lepidoptera: Pieridae), was associated with plant defense traits of putative host plants. We conducted feeding assays using larvae of three Pieris species and 10 species of the Brassicaceae family possessing different leaf physical traits and glucosinolate profile measurements. The larvae of Pieris rapae responded differently in the feeding assays compared with the other two Pieris species. This difference was associated with differences in glucosinolate profiles but not with variations in physical traits of the host plants. This result suggests that individual Pieris species are adapted to a subset of glucosinolate profiles within the Brassicaceae. Our results support the idea that the host ranges of Pieris species depend on larval responses to glucosinolate diversification in the host species, supporting the hypothesis of coevolution between butterflies and host plants mediated by the chemical arms race.

Molecular Basis of the Evolution of Methylthioalkylmalate Synthase and the Diversity of Methionine-Derived Glucosinolates.

The globally cultivated Brassica species possess diverse aliphatic glucosinolates, which are important for plant defense and animal nutrition. The committed step in the side chain elongation of methionine-derived aliphatic glucosinolates is catalyzed by methylthioalkylmalate synthase, which likely evolved from the isopropylmalate synthases of leucine biosynthesis. However, the molecular basis for the evolution of methylthioalkylmalate synthase and its generation of natural product diversity in Brassica is poorly understood. Here, we show that Brassica genomes encode multiple methylthioalkylmalate synthases that have differences in expression profiles and 2-oxo substrate preferences, which account for the diversity of aliphatic glucosinolates across Brassica accessions. Analysis of the 2.1 Å resolution x-ray crystal structure of Brassica juncea methylthioalkylmalate synthase identified key active site residues responsible for controlling the specificity for different 2-oxo substrates and the determinants of side chain length in aliphatic glucosinolates. Overall, these results provide the evolutionary and biochemical foundation for the diversification of glucosinolate profiles across globally cultivated Brassica species, which could be used with ongoing breeding strategies toward the manipulation of beneficial glucosinolate compounds for animal health and plant protection.

Antagonistic selection and pleiotropy constrain the evolution of plant chemical defenses.

When pleiotropy is present, genetic correlations may constrain the evolution of ecologically important traits. We used a quantitative genetics approach to investigate constraints on the evolution of secondary metabolites in a wild mustard, Boechera stricta. Much of the genetic variation in chemical composition of glucosinolates in B. stricta is controlled by a single locus, BCMA1/3. In a large-scale common garden experiment under natural conditions, we quantified fitness and glucosinolate profile in two leaf types and in fruits. We estimated genetic variances and covariances (the G-matrix) and selection on chemical profile in each tissue. Chemical composition of defenses was strongly genetically correlated between tissues. We found antagonistic selection between defense composition in leaves and fruits: compounds that were favored in leaves were disadvantageous in fruits. The positive genetic correlations and antagonistic selection led to strong constraints on the evolution of defenses in leaves and fruits. In a hypothetical population with no genetic variation at BCMA1/3, we found no evidence for genetic constraints, indicating that pleiotropy affecting chemical profile in multiple tissues drives constraints on the evolution of secondary metabolites.

Glucosinolates profiles in Maca phenotypes cultivated in Peru and China (Lepidium peruvianum syn. L. meyenii)

HPLC glucosinolate (GCSN) profiles and concentration levels were examined in hypocotyls of the four prime Maca phenotypes (Lepidium peruvianum synonym L. meyenii) labelled as “Yellow”, “Black”, “Red” and “Purple”, grown in Peru (Pe) and/or China (Cn). In Trial I, glucotropaeolin (GLCT) and m-methoxyglucotropaeolin (MGLCT) content, and their ratios, was determined in commercial Maca products of Pe origin and compared with similar products declared as of Cn origin. In Trial II, Maca was propagated and cultivated either in Ancash – Peru, according to a traditional single stage planting system, or in Shangri-La – Cn, applying a two-stage Maca planting procedure adopted by Maca growers in Yunnan. Irrespective of the phenotype, in the Pe cultivation system, cylindrical elongated and pointed Maca hypocotyls (H) were harvested in the mixed crop, while disfigured Maca tubers resembling “ginseng-type root” (G) were predominant in the crop harvested in Cn. Two peaks of GLCT and MGLCT were detected in all analysed hypocotyls of the four Maca phenotypes grown in Pe, but only one peak (GLCT) was detected in the Maca phenotypes grown in Shangri-La, Cn. Significantly higher GLCT values were detected in all the Maca phenotypes grown in Cn than in Pe (P < 0.05), with the highest content recorded in the Black and Purple H-shaped while MGLCT was the highest in Yellow G-shaped Cn Maca tubers. Cn-made “Chinese Maca tablets” contained both GLCT and MGLCT. This indicates that Maca imported from Pe could have been used in the formulation - a fact which was subsequently confirmed by the manufacturer.

Glucosinolates of the only three Brassicales indigenous to French Polynesia

The glucosinolate (GL) profiles in leaf and stem of Rorippa sarmentosa (G.Forst. ex DC.) J.F.Macbr., Lepidium bidentatum Montin var. bidentatum, and Capparis spinosa subsp. cordifolia (Lam.) Fici indigenous to French Polynesia were investigated for the first time using LC-MS analysis. In the present study, we have established the presence of 8 known GLs in R. sarmentosa: 4-(methylsulfinyl)butyl- (1), but-3-enyl- (2), 5-(methylsulfinyl)pentyl- (3), 6-(methylsulfinyl)hexyl- (4), indol-3-ylmethyl- (6), 2-phenylethyl- (7), 8-(methylsulfinyl)octyl- (8), and 9-(methylsulfinyl)nonyl- (9) GLs. We have also tentatively identified for the first time the presence in R. sarmentosa of 7-(methylsulfinyl)heptyl GL (5). In addition, we have identified two known GLs in L. bidentatum var. bidentatum: benzyl- (10) and 4-methoxybenzyl- (11) GLs. Finally, the known methyl GL (12) was shown to be largely predominant in C. spinosa subsp. cordifolia.

Transcriptional Reprogramming of Arabidopsis thaliana Defence Pathways by the Entomopathogen Beauveria bassiana Correlates With Resistance Against a Fungal Pathogen but Not Against Insects.

The entomopathogenic fungus Beauveria bassiana can adopt an endophytic lifestyle by colonising a wide array of plant species. Beauveria-colonised plants can show enhanced resistance against insects and plant pathogens alike. However, little is known about the molecular and physiological mechanisms that govern such interactions. Here, we assessed the effects of two B. bassiana strains (BG11, FRh2) on the growth of Arabidopsis thaliana and its resistance against two herbivore species and a phytopathogen. Plant responses were studied on the transcriptomic and metabolic level using microarrays and by measuring changes in defence-related phytohormones and glucosinolates (GLSs). Root inoculation with B. bassiana BG11 significantly increased plant growth, while FRh2 had no such effect. Both Beauveria strains decreased leaf lesion area caused by the phytopathogen Sclerotinia sclerotiorum but did not affect population growth of the aphid Myzus persicae or the growth of Plutella xylostella caterpillars. Microarray analyses of leaves from endophyte-inoculated A. thaliana provided evidence for transcriptional reprogramming of plant defence pathways, with strain-specific changes in the expression of genes related to pathogenesis, phytoalexin, jasmonic (JA), and salicylic acid (SA) signalling pathways. However, B. bassiana colonisation did not result in higher concentrations of JA and SA or major changes in leaf GLS profiles. We conclude that the endophyte B. bassiana induces plant defence responses and hypothesise that these contribute to enhanced resistance against S. sclerotiorum.

Antimicrobial and Cytotoxic Activities of Lepidium latifolium L. Hydrodistillate, Extract and Its Major Sulfur Volatile Allyl Isothiocyanate

The cultivated Lepidium latifolium L. was investigated to decipher its glucosinolate profile, antimicrobial, and cytotoxic activities. HPLC/ESI-MS analyses of the intact glucosinolates and GC/MS analysis of their hydrolysis products showed the presence of sinigrin (1), glucocochlearin (2), glucotropaeolin (3), and 4-methoxyglucobrassicin (4). Hydrodistillate, extract, and allyl isothiocyanate, the main volatile resulting from sinigrin degradation, showed antimicrobial activity against all eleven tested pathogenic and food spoilage bacteria and fungi, with highest effect observed against Candida albicans with MIC50 8 and 16 μg/mL. Hydrodistillate and extract showed the best cytotoxic activity on bladder cancer UM-UC-3 cell line during an incubation time of 24 h (IC50 192.9 and 133.8 μg/mL, respectively), while the best effect on glioblastoma LN229 cell line was observed after 48 h (IC50 110.8 and 30.9 μg/mL, respectively). Pure allyl isothiocyanate displayed a similar trend in cytotoxic effect on both cell lines (IC50 23.3 and 36.5 μg/mL after 24 h and 48 h, respectively).

Bunias erucago L.: Glucosinolate Profile and In Vitro Biological Potential.

Bunias erucago belongs to the Brassicaceae family, which represents a forgotten crop of the Euro-Mediterranean area. The aim of the present study was to determine the glucosinolate profile in different plant parts and biological properties (antioxidant, anticholinesterase, and cytotoxic activities) of the isolates containing glucosinolate breakdown products. The chemical profiles were determined by using HPLC-PDA-MS/MS of desulfoglucosinolates and GC-MS of glucosinolate degradation products. The analysis of B. erucago showed the presence of seven glucosinolates: gluconapin (1), glucoraphasatin (2), glucoraphenin (3), glucoerucin (4), glucoraphanin (5), glucotropaeolin (6), and glucosinalbin (7). The total glucosinolate content ranged from 7.0 to 14.6 µmol/g of dry weight, with the major glucosinolate glucosinalbin in all parts. The antioxidant activity of all volatile isolates was not notable. At a tested concentration of 227 μg/mL, flower hydro-distillate (FH) showed good AChE inhibition, i.e., 40.9%, while root hydro-distillate (RH) had good activity against BChE, i.e., 54.3%. FH showed the best activity against both tested human bladder cancer cell lines, i.e., against T24 after 72 h, which have IC50 of 16.0 μg/mL, and against TCCSUP after 48 h with IC50 of 7.8 μg/mL, and can be considered as highly active. On the other hand, RH showed weak activity against tested cancer cells.

Variations in the glucosinolates of the individual edible parts of three stem mustards (Brassica juncea).

The composition and content of glucosinolates were investigated in the edible parts (petioles, peel and flesh) of tuber mustard, bamboo shoots mustard and baby mustard by high-performance liquid chromatography to reveal the association between the different cooking methods and their glucosinolate profiles. Eight glucosinolates were identified from tuber mustard and baby mustard, including three aliphatic glucosinolates, four indole glucosinolates and one aromatic glucosinolate. Only six of the eight glucosinolates were detected in bamboo shoots mustard. The results show that the distribution and content of glucosinolates varied widely among the different tissues and species. The highest contents of glucosinolates in tuber mustard, bamboo shoots mustard and baby mustard were found in flesh, petioles and peel, respectively. The content of total glucosinolates ranged from 5.21 µmol g–1 dry weight in bamboo shoots mustard flesh to 25.64 µmol g−1 dry weight in baby mustard peel. Aliphatic glucosinolates were predominant in the three stem mustards, followed by indole and aromatic glucosinolates. Sinigrin was the predominant glucosinolate in the three stem mustards. Sinigrin content in tuber mustard was slightly higher than that in baby mustard and much higher than that in bamboo shoots mustard, suggesting that the pungent-tasting stem mustards contained more sinigrin. In addition, a principal components analysis showed that bamboo shoots mustard was distinguishable from the other two stem mustards. A variance analysis indicated that the glucosinolates were primarily influenced by a species × tissue interaction. The correlations among glucosinolates were also analysed.

Glucosinolates in wild and cultivated Brassica montana Pourret (Brassicaceae) from southern France

The glucosinolate (GL) profiles of wild and cultivated Brassica montana Pourret (seed, stem, leaf, root) from southern France were established using LC-MS analysis. In this investigation we have confirmed the presence of 9 known GLs: but-3-enyl- (1), prop-2-enyl- (2), pent-4-enyl- (3), (2R)-2-hydroxybut-3-enyl- (4), 4-hydroxyindol-3-ylmethyl- (5), 4-(methylsulfinyl)butyl- (6), 4-(methylsulfanyl)butyl- (7), 1-methoxyindol-3-ylmethyl- (8), and indol-3-ylmethyl (9) GL. In addition, we tentatively identified for the first time the presence in the plant of 1-methylpropyl GL (10) in all plant parts. In addition, we have pointed out differences in GL profiles between plant organs and between wild and cultivated B. montana.

Applications of water blanching, surface contacting ultrasound-assisted air drying, and their combination for dehydration of white cabbage: Drying mechanism, bioactive profile, color and rehydration property

This work studied the influences of water blanching pretreatment (30 s), surface contacting ultrasound (492.3 and 1131.1 W/m2) assisted air drying, and their combination on drying kinetics and quality of white cabbage. Contacting sonication was performed by placing samples on an ultrasonic vibration plate, and the drying temperature was 60 °C. Through drying kinetic analysis and numerical simulation considering internal and external resistances and shrinkage, it was found that both blanching pretreatment and contacting sonication during drying intensified internal water diffusion and external water exchange to shorten cabbage drying time. Meanwhile, blanching pretreatment was more effective to enhance the drying process. The largest reduction of drying time (from 145 min to 24 min) was obtained when sequential blanching and contacting sonication at 1131.1 W/m2 were conducted. Dehydrated cabbages with blanching pretreatment were characterized by green color and high retention of vitamin C, while a severe loss of vitamin C was found in dried cabbages without blanching pretreatment. Moreover, although both blanching and contacting sonication shortened the drying time, the losses of phenolics, glucosinolates and resulting breakdown products were not alleviated. Contents of total phenolics, one glucosinolates (sinigrin) and one glucobrassicin breakdown product (indole-3-acetoritrile) in only air dried cabbages were significantly (p < 0.05) higher than that in samples dried by sequential blanching and contacting ultrasound-assisted drying. The changes of glucosinolate profile and resulting degradation products under different treatments were irregular, due to complex bioconversion pathways included.

Divergence in Glucosinolate Profiles between High- and Low-Elevation Populations of Arabidopsis halleri Correspond to Variation in Field Herbivory and Herbivore Behavioral Preferences.

Variation in local herbivore pressure along elevation gradients is predicted to drive variation in plant defense traits. Yet, the extent of intraspecific variation in defense investment along elevation gradients, and its effects on both herbivore preference and performance, remain relatively unexplored. Using populations of Arabidopsis halleri (Brassicaceae) occurring at different elevations in the Alps, we tested for associations between elevation, herbivore damage in the field, and constitutive chemical defense traits (glucosinolates) assayed under common-garden conditions. Additionally, we examined the feeding preferences and performance of a specialist herbivore, the butterfly Pieris brassicae, on plants from different elevations in the Alps. Although we found no effect of elevation on the overall levels of constitutive glucosinolates in leaves, relative amounts of indole glucosinolates increased significantly with elevation and were negatively correlated with herbivore damage in the field. In oviposition preference assays, P. brassicae females laid fewer eggs on plants from high-elevation populations, although larval performance was similar on populations from different elevations. Taken together, these results support the prediction that species distributed along elevation gradients exhibit genetic variation in chemical defenses, which can have consequences for interactions with herbivores in the field.