High Levels Of Glucosinolates Research Articles

Modified atmosphere affects glucosinolate metabolism during postharvest storage of broccoli

Broccoli is a vegetable with a growing consumer demand worldwide due to its important nutritional properties, including high amounts of glucosinolates. However, this vegetable has a short postharvest life and quickly loses its organoleptic and nutritional quality. Modified atmosphere is one of the numerous methodologies used to delay deterioration during postharvest storage of broccoli heads. In this study, the effect of a modified atmosphere during postharvest storage of broccoli on glucosinolate metabolism was evaluated. Five glucosinolates were identified by using a UPLC system coupled to a mass spectrometer. We detected one aliphatic glucosinolate and four indolic glucosinolates, and their concentration was found to decrease during storage. The decrease in content was less marked, and in some cases, an increased level was observed in the treated samples. Moreover, the treatment made it possible to maintain higher expression (analyzed by real-time quantitative PCR) of genes linked to glucosinolate biosynthesis. We also detected an increased expression of some genes related to indolic glucosinolate biosynthesis. Overall, storage of broccoli in modified atmospheres allowed for maintaining better visual quality and higher levels of glucosinolates.

The Beneficial Effect of Selenium-Enriched Broccoli on the Quality Characteristics of Bread

Broccoli is one of the most valuable representatives of the Brassicaceae family, characterized by high levels of glucosinolates and fiber, antioxidant status and tolerance to high selenium (Se) concentrations. To evaluate the efficiency of Se-enriched broccoli utilization in bread production, 4% of dry broccoli powder was added to dough using non-fortified and Se-biofortified broccoli florets. The resulting functional products were characterized by enhanced porosity, crump acidity and a specific volume exceeding those of the control bread by 109–110%, 114–121% and 107–112%, respectively, with the lower levels typical to bread with broccoli non-fortified with Se. By supplying broccoli powder to bread, the dietary fiber content of the product was enhanced by 2.1 times. Selenium-enriched broccoli powder supply improved the ascorbic acid and total phenolic content in bread by 37.5 and 2.03 times compared with the control. The effect was less pronounced in case of non-fortified broccoli supplementation due to the beneficial effect of Se on broccoli florets’ antioxidant status. Selenium-enriched broccoli supply significantly decreased the intensity of bread crumb hardening during storage. High Se-biofortification level (5.6) and insignificant Se losses during bread baking (less than 4%) confirm high prospects of Se-enriched broccoli utilization in the production of new functional bread with elevated levels of antioxidants, Se and dietary fiber.

Targeted editing of multiple homologues of GTR1 and GTR2 genes provides the ideal low-seed, high-leaf glucosinolate oilseed mustard with uncompromised defence and yield.

Glucosinolate content in the two major oilseed Brassica crops-rapeseed and mustard has been reduced to the globally accepted Canola quality level (<30 μmoles/g of seed dry weight, DW), making the protein-rich seed meal useful as animal feed. However, the overall lower glucosinolate content in seeds as well as in the other parts of such plants renders them vulnerable to biotic challenges. We report CRISPR/Cas9-based editing of glucosinolate transporter (GTR) family genes in mustard (Brassica juncea) to develop ideal lines with the desired low seed glucosinolate content (SGC) while maintaining high glucosinolate levels in the other plant parts for uncompromised plant defence. Use of three gRNAs provided highly efficient and precise editing of four BjuGTR1 and six BjuGTR2 homologues leading to a reduction of SGC from 146.09 μmoles/g DW to as low as 6.21 μmoles/g DW. Detailed analysis of the GTR-edited lines showed higher accumulation and distributional changes of glucosinolates in the foliar parts. However, the changes did not affect the plant defence and yield parameters. When tested against the pathogen Sclerotinia sclerotiorum and generalist pest Spodoptera litura, the GTR-edited lines displayed a defence response at par or better than that of the wild-type line. The GTR-edited lines were equivalent to the wild-type line for various seed yield and seed quality traits. Our results demonstrate that simultaneous editing of multiple GTR1 and GTR2 homologues in mustard can provide the desired low-seed, high-leaf glucosinolate lines with an uncompromised defence and yield.

Morpho-anatomical, biochemical and molecular genetic responses of canola (Brassica napus L.) to sulphur application

Brassica napus (canola), a major economic crop in Egypt, contains much oils and proteins. In the present study, the foliar applications of ammonium sulphate (A.S.) [(NH4)2SO4] (0, 1% 0.2% and 0.3%) to canola plants had distinctive impacts on the morpho-anatomical, biochemical, and molecular genetic responses. Interestingly, there is a positive impact when sulphur (S) is foliarly applied at 0.2% of A.S. as revealed in antioxidants, flavonoids, total carbohydrates, and protein contents which were significantly affected. On the other hand, higher levels of glucosinolates were recorded for 0.3% and 1% A.S. (4.838 and 1.905, respectively). The electrophoretic analysis of proteins displayed 51 bands of molecular weights ranging from 8.555 to 240.6 kDa with 88.24% polymorphism with a mean band frequency of 0.373. Cytotoxicity assay revealed that the lower cell death was detected in treated root tips of canola plants following 0.2% A.S. treatment, as compared to control. With increasing of sulphur treatment, the root cortex thickness, number of conducting elements, and pericycle thickness decreased while root pith area increased. In canola leaves of high S level, the leaf blade thickness, the thickness of abaxial and adaxial epidermis surface, mesophyll thickness, and metaxylem area increased, while the xylem conducting elements number decreased. Moreover, SCoT molecular markers have been used to evaluate the genetic variation among Brassica napus genotypes subjected to different A.S. treatments. Four of the seven SCoT primers were revealed to be polymorphic in both treated and untreated samples. A total of 39 amplicons, ranging in size from 200 to 1080 bp, were amplified, with 9 (23.07%) of them being polymorphic. Clustering dendogram based on SCot markers data divided Brassica genotypes into two main clusters based on similarity coefficients indices. B. napus treated with 0.2% A.S. was separated in a distinct cluster. Furthermore, treatments with sulphur enhanced the activity of antioxidant enzymes as well as the expression level of their encoding genes (CAT, catalase; POD, peroxidase; APX, ascorbate peroxidase; SOD, superoxide dismutase; GR, glutathione reductase), particularly at 1% and 0.2% A.S. treatments. Taken together, this study revealed that foliar application of sulphur treatments, particularly at 0.2%, have a great potential to improve canola crop.

Profiling of Polyphenols and Glucosinolates in Kale and Broccoli Microgreens Grown under Chamber and Windowsill Conditions by Ultrahigh-Performance Liquid Chromatography High-Resolution Mass Spectrometry

Vegetables from the Brassica family are rich in many health-beneficial components, including high levels of polyphenols and glucosinolates (GSLs). However, their exact metabolite compositions are highly affected by cultivating and environmental conditions. Here, we provide the first report of polyphenol and GSL composition of kale and broccoli microgreens grown in growth chamber and windowsill environments. The samples were harvested 10 days after sowing and analyzed using ultrahigh-performance liquid chromatography high-resolution mass spectrometry. Principal component analysis was performed to visualize group clustering, trends, and discriminative ion features. Flavonol derivatives (21 in kale and 7 in broccoli) and hydroxycinnamic acid derivatives (14 in kale and 22 in broccoli) were identified under both growing conditions. Additionally, GSLs, including 7 in kale and 9 in broccoli, were detected. The results demonstrated a clear variation in secondary metabolites between the two growing conditions. The discriminative ion features were hydroxycinnamic acid esters of flavonols and indolic GSLs. Compared to chamber conditions, hydroxycinnamic acid esters of flavonols such as kaempferol-3-disinapoyl-triglucoside-7-diglucoside, kaempferol-3-disinpapoyl-triglucoside-7-glucoside, and kaempferol-3-disinpapoyl-diglucoside-7-glucoside were found to be greater in the windowsill-grown vegetables. The contents of 4-methoxyglucobrassicin and neoglucobrassicin, on the other hand, were greater in the chamber-grown ones. The results suggest that kale and broccoli microgreens grown under commercial- and in-home-grown conditions have different secondary metabolite compositions.

Oxygen plasma modulates glucosinolate levels without affecting lipid contents and composition in Brassica napus seeds.

Rapeseed contains high levels of glucosinolates (GSLs), playing pivotal roles in defense against herbivores and pests. As their presence in rapeseed reduces the value of the meal for animal feeding, intensive efforts to reduce them produced low-seed GSL cultivars. However, there is no such variety suitable for the south part of Japan. Here, we tested the effects of cold oxygen plasma (oxygen CP) on seed germination and GSL and lipid content, in 3 rapeseed cultivars. According to the cultivars, oxygen CP slightly stimulated seed germination and modified the GSL levels, and decreased GSL levels in Kizakinonatane but increased those in Nanashikibu. In contrast, it negligibly affected the lipid content and composition in the 3 cultivars. Thus, oxygen CP modulated seed GSL levels without affecting seed viability and lipid content. Future optimization of this technique may help optimize rapeseed GSL content without plant breeding.

Preharvest UVB Application Increases Glucosinolate Contents and Enhances Postharvest Quality of Broccoli Microgreens.

Broccoli microgreens have shown potential health benefits due to their high glucosinolate (GL) levels. Previously, we observed that postharvest UVB treatment did not have much effect on increasing GLs in broccoli microgreens. In this study, we investigated the influence of preharvest UVB irradiation on GL levels in broccoli microgreens. UHPLC-ESI/ITMS analysis showed that preharvest UVB treatments with UVB 0.09 and 0.27 Wh/m2 significantly increased the glucoraphanin (GLR), glucoerucin (GLE), and total aliphatic GL levels by 13.7 and 16.9%, respectively, in broccoli microgreens when measured on harvest day. The nutritional qualities of UVB-treated microgreens were stable during 21-day storage, with only small changes in their GL levels. Broccoli microgreens treated before harvest with UVB 0.27 Wh/m2 and 10 mM CaCl2 spray maintained their overall quality, and had the lowest tissue electrolyte leakage and off-odor values during the storage. Furthermore, preharvest UVB 0.27 Wh/m2 treatment significantly increased GL biosynthesis genes when evaluated before harvest, and reduced the expression level of myrosinase, a gene responsible for GL breakdown during postharvest storage. Overall, preharvest UVB treatment, together with calcium chloride spray, can increase and maintain health-beneficial compound levels such as GLs and prolong the postharvest quality of broccoli microgreens.

Hijacking the Mustard-Oil Bomb: How a Glucosinolate-Sequestering Flea Beetle Copes With Plant Myrosinases

Myrosinase enzymes play a key role in the chemical defense of plants of the order Brassicales. Upon herbivory, myrosinases hydrolyze the β-S-linked glucose moiety of glucosinolates, the characteristic secondary metabolites of brassicaceous plants, which leads to the formation of different toxic hydrolysis products. The specialist flea beetle, Phyllotreta armoraciae, is capable of accumulating high levels of glucosinolates in the body and can thus at least partially avoid plant myrosinase activity. In feeding experiments with the myrosinase-deficient Arabidopsis thaliana tgg1 × tgg2 (tgg) mutant and the corresponding Arabidopsis Col-0 wild type, we investigated the influence of plant myrosinase activity on the metabolic fate of ingested glucosinolates in adult P. armoraciae beetles. Arabidopsis myrosinases hydrolyzed a fraction of ingested glucosinolates and thereby reduced the glucosinolate sequestration rate by up to 50% in adult beetles. These results show that P. armoraciae cannot fully prevent glucosinolate hydrolysis; however, the exposure of adult beetles to glucosinolate hydrolysis products had no impact on the beetle’s energy budget under our experimental conditions. To understand how P. armoraciae can partially prevent glucosinolate hydrolysis, we analyzed the short-term fate of ingested glucosinolates and found them to be rapidly absorbed from the gut. In addition, we determined the fate of ingested Arabidopsis myrosinase enzymes in P. armoraciae. Although we detected Arabidopsis myrosinase protein in the feces, we found only traces of myrosinase activity, suggesting that P. armoraciae can inactivate plant myrosinases in the gut. Based on our findings, we propose that the ability to tolerate plant myrosinase activity and a fast glucosinolate uptake mechanism represent key adaptations of P. armoraciae to their brassicaceous host plants.

Elevated CO2 improves glucosinolate metabolism and stimulates anticancer and anti-inflammatory properties of broccoli sprouts

Sprouting process enhances plant bioactive compounds. Broccoli (Brassica oleracea L) sprouts are well known for their high levels of glucosinolates (GLs), amino acids, and antioxidants, which offer outstanding biological activities with positive impacts on plant metabolism. Elevated CO2 (eCO2, 620 ppm) was applied for 9 days to further improve nutritive and health-promoting values of three cultivars of broccoli sprouts i.e., Southern star, Prominence and Monotop. eCO2 improved sprouts growth and induced GLs accumulation e.g., glucoraphanin, possibly through amino acids production e.g., high methionine and tryptophan. There were increases in myrosinase activity, which stimulated GLs hydrolysis to yield health-promoting sulforaphane. Interestingly, low levels of ineffective sulforaphane nitrile were detected and positively correlated with reduced epithiospecifier protein after eCO2 treatment. High glucoraphanin and sulforaphane levels in eCO2 treated sprouts improved the anticarcinogenic and anti-inflammatory properties of their extracts. In conclusion, eCO2 treatment enriches broccoli sprouts with health-promoting metabolites and bioactivities.

Intake of total cruciferous vegetable and its contents of glucosinolates and isothiocyanates, glutathione S-transferases polymorphisms and breast cancer risk: a case-control study in China.

Cruciferous vegetables contain high levels of glucosinolates (GSL) and isothiocyanates (ITC). ITC are known to induce glutathione S-transferases (GST) and thus exert their anticarcinogenic effects. This study explored the combined effects of cruciferous vegetable, GSL and ITC intake and GST polymorphisms on breast cancer risk. A total of 737 breast cancer cases and 756 controls were recruited into this case-control study. OR and 95 % CI were assessed by multivariable logistic regression. Higher cruciferous vegetable, GSL and ITC intakes were inversely associated with breast cancer risk, with adjusted OR of 0·48 (95 % CI 0·35, 0·65), 0·54 (95 % CI 0·40, 0·74) and 0·62 (95 % CI 0·45, 0·84), respectively. Compared with women carrying the GSTP1 rs1695 wild AA genotype and high cruciferous vegetable, GSL or ITC intake, carriers of the AA genotype with low cruciferous vegetable, GSL and ITC intake had greater risk of breast cancer, with adjusted OR of 1·43 (95 % CI 1·01, 1·87), 1·34 (95 % CI 1·02, 1·75) and 1·37 (95 % CI 1·05, 1·80), respectively. Persons with the GSTM1-null genotype and lower intake of cruciferous vegetables, GSL and ITC had higher risk of breast cancer than those with the GSTM1-present genotype and higher intake, with OR of 1·42 (95 % CI 1·04, 1·95), 1·43 (95 % CI 1·05, 1·96) and 1·45 (95 % CI 1·06, 1·98), respectively. Among women possessing the GSTT1-present genotype, low intake of cruciferous vegetables, GSL or ITC was associated with higher risk of breast cancer. But these interactions were non-significant. This study indicated that there were no significant interactions between cruciferous vegetable, GSL or ITC intake and GST polymorphisms on breast cancer risk.

Ontogenetic differences in the chemical defence of flea beetles influence their predation risk

Abstract Several insect species have evolved two‐component chemical defences that enable the rapid release of deterrent or toxic metabolites upon predator attack. However, whether these chemical defences vary across insect ontogeny and how this affects the predation risk of different life stages has rarely been addressed. The horseradish flea beetle Phyllotreta armoraciae possesses a two‐component chemical defence that consists of sequestered glucosinolates and an insect myrosinase capable of converting the non‐toxic glucosinolates to deterrent isothiocyanates. Here, we show that the levels of sequestered glucosinolates only varied 2‐fold across beetle ontogeny, but that insect myrosinase activity differed up to 43‐fold among ontogenetic stages. Specifically, glucosinolate levels were 1.5‐fold lower in the larvae of P. armoraciae than in pupae, but they showed 43.4‐fold higher levels of myrosinase activity. Consistent with the distinct levels of myrosinase activity in larvae and pupae, only larvae released high amounts of toxic isothiocyanates when they were attacked by the generalist predator Harmonia axyridis. P. armoraciae larvae deterred the predator and survived one attack, whereas pupae were killed. Feeding of P. armoraciae larvae on plants that differed in glucosinolates and plant myrosinase activity influenced the accumulation of glucosinolates in larvae and their subsequent interaction with H. axyridis. Larvae with low levels of sequestered glucosinolates were much more susceptible to predation than larvae containing high glucosinolate levels. Our results demonstrate that sequestered plant defence metabolites selectively protect specific ontogenetic stages of P. armoraciae from predation. The strong influence of plant defensive chemistry on sequestration indicates that predators have played an important role in the evolution of host use in this specialist herbivore. The distinct life styles of flea beetle life stages and their strategies to prevent predation by biologically relevant predator communities deserve further investigations. A free Plain Language Summary can be found within the Supporting Information of this article.

Dual-locus DNA metabarcoding reveals southern hairy-nosed wombats (Lasiorhinus latifrons Owen) have a summer diet dominated by toxic invasive plants.

Habitat degradation and summer droughts severely restrict feeding options for the endangered southern hairy-nosed wombat (SHNW; Lasiorhinus latifrons). We reconstructed SHNW summer diets by DNA metabarcoding from feces. We initially validated rbcL and ndhJ diet reconstructions using autopsied and captive animals. Subsequent diet reconstructions of wild wombats broadly reflected vegetative ground cover, implying local rather than long-range foraging. Diets were all dominated by alien invasives. Chemical analysis of alien food revealed Carrichtera annua contains high levels of glucosinolates. Clinical examination (7 animals) and autopsy (12 animals) revealed that the most degraded site also contained most individuals showing signs of glucosinolate poisoning. We infer that dietary poisoning through the ingestion of alien invasives may have contributed to the recent population crashes in the region. In floristically diverse sites, individuals appear to be able to manage glucosinolate intake by avoidance or episodic feeding but this strategy is less tractable in the most degraded sites. We conclude that recovery of the most affected populations may require effective Carrichtera management and interim supplementary feeding. More generally, we argue that protection against population decline by poisoning in territorial herbivores requires knowledge of their diet and of those food plants containing toxic principles.

Antiproliferative, Proapoptotic, Antioxidant and Antimicrobial Effects of Sinapis nigra L. and Sinapis alba L. Extracts.

High Brassicaceae consumption reduces the risk of developing several cancer types, probably due to high levels of glucosinolates. Extracts from Sinapis nigra L. (S. nigra) and Sinapis alba L. (S. alba) have been obtained from leaves and seeds under different conditions using ethanol/water mixtures because their glucosinolates are well accepted by the food industry. The EtOH/H2O 8:2 mixture gives better yields in glucosinolate amounts from ground seeds, mainly, sinalbin in S. alba and sinigrin in S. nigra. The highest antiproliferative activity in both non-tumor and tumor cell lines was induced by S. alba seeds extract. To evaluate whether the effect of Sinapis species (spp) was only due to glucosinolate content or whether it was influenced by the extracts’ complexity, cells were treated with extracts or glucosinolates, in the presence of myrosinase. Pure sinigrin did not modify cell proliferation, while pure sinalbin was less effective than the extract. The addition of myrosinase increased the antiproliferative effects of the S. nigra extract and sinigrin. Antiproliferative activity was correlated to Mitogen-Activated Protein Kinases modulation, which was cell and extract-dependent. Cell-cycle analysis evidenced a proapoptotic effect of S. alba on both tumor cell lines and of S. nigra only on HCT 116. Both extracts showed good antimicrobial activity in disc diffusion tests and on ready-to-eat fresh salad. These results underline the potential effects of Sinapis spp in chemoprevention and food preservation.

Genome-wide identification of loci affecting seed glucosinolate contents in Brassica napus L.

Glucosinolates are amino acid-derived secondary metabolites that act as chemical defense agents against pests. However, the presence of high levels of glucosinolates severely diminishes the nutritional value of seed meals made from rapeseed (Brassica napus L.). To identify the loci affecting seed glucosinolate content (SGC), we conducted genome-wide resequencing in a population of 307 diverse B. napus accessions from the three B. napus ecotype groups, namely, spring, winter, and semi-winter. These resequencing data were used for a genome-wide association study (GWAS) to identify the loci affecting SGC. In the three ecotype groups, four common and four ecotype-specific haplotype blocks (HBs) were significantly associated with SGC. To identify candidate genes controlling SGC, transcriptome analysis was carried out in 36 accessions showing extreme SGC values. Analyses of haplotypes, genomic variation, and candidate gene expression pointed to five and three candidate genes in the common and spring group-specific HBs, respectively. Our expression analyses demonstrated that additive effects of the three candidate genes in the spring group-specific HB play important roles in the SGC of B. napus.

Nutrition versus defense: Why Myzus persicae (green peach aphid) prefers and performs better on young leaves of cabbage.

Plant leaves of different ages differ in nutrients and toxic metabolites and thus exhibit various resistance levels against insect herbivores. However, little is known about the influence of leaf ontogeny on plant resistance to phloem-feeding insects. In this study, we found that the green peach aphid, Myzus persicae, preferred to settle on young cabbage leaves compared with mature or old leaves, although young leaves contained the highest concentration of glucosinolates. Furthermore, aphids feeding on young leaves had higher levels of glucosinolates in their body, but aphids performed better on young leaves in terms of body weight and population growth. Phloem sap of young leaves had higher amino acid:sugar molar ratio than mature leaves, and aphids feeding on young leaves showed two times longer phloem feeding time and five times more honeydew excretion than on other leaves. These results indicate that aphids acquired the highest amount of nutrients and defensive metabolites when feeding on young cabbage leaves that are strong natural plant sinks. Accordingly, we propose that aphids generally prefer to obtain more nutrition rather than avoiding host plant defense, and total amount of nutrition that aphids could obtain is significantly influenced by leaf ontogeny or source-sink status of feeding sites.

Broccoli Consumption Impacts the Human Gastrointestinal Microbiota

BackgroundThe human gastrointestinal (GI) microbiota is increasingly linked to health outcomes; however, our understanding of how specific foods alter the microbiota is limited. Cruciferous vegetables such as broccoli have been associated with cancer prevention as a result of their high levels of glucosinolates, especially glucoraphanin. The activation of glucoraphanin to its isothiocyanate form, sulforaphane, is dependent on the enzyme myrosinase. Myrosinase is naturally found in broccoli, but is degraded by cooking. It has been hypothesized that plasma sulforaphane observed in persons eating cooked broccoli may be related to glucoraphanin hydrolysis by microbial myrosinase. Myrosinase activity is greater in rodents who regularly consume cruciferous vegetables compared to those who do not, suggesting a priming effect on the microbiota. However, it remains to be discovered which members of the microbiota are responsible for this action in clinical populations.ObjectiveWe aimed to determine the impact of broccoli consumption on the GI microbiota of healthy adult men and women as a means to understand the role of microbes in glucosinolate hydrolysis.MethodsA controlled feeding, randomized, crossover study consisting of two 17‐day treatment periods separated by a 24‐day washout was conducted in healthy adults (n=18). Participants were fed at weight maintenance, and received a Brassica‐free control diet or the same diet with 200 g of cooked broccoli and 20 g of fresh daikon radish (as a source of plant myrosinase) per day. Fecal samples were collected at baseline and at the end of each treatment period for microbial analysis. Following DNA isolation, bacterial, archaeal, and fungal barcoded amplicon pools were generated using a Fluidigm Access Array system prior to high‐throughput sequencing on an Illumina MiSeq. Data were analyzed using QIIME 1.8.0 and 1.9.1 and SAS 9.4.ResultsBeta diversity analysis based on 97% operational taxonomic unit composition and abundances indicated that bacterial communities were impacted by treatment (p=0.03). Broccoli consumption resulted in a significant change in the proportion of Bacteroidetes relative to Firmicutes, whereby participants consuming broccoli increased this ratio by 37% from baseline to end, compared to a 5% reduction during the control period (p=0.02). Bacteroides increased by 6% following broccoli consumption and decreased by 2% in the control group, but the difference between these two groups was not statistically significant (p=0.15).ConclusionThese novel results reveal that broccoli consumption affects the diversity and composition of the GI microbiota of healthy adults. These data help fill the gap in knowledge related to the role of bacterial hydrolysis of phytonutrients. The increase in Bacteroides spp. is particularly relevant because Bacteroides thetaiotaomicron has been shown in vitro to utilize glucosinolates. Additional study is ongoing to determine if phenotypic responses are related to archaea and body mass index.Support or Funding InformationFunding provided by the National Cancer Institute and the USDA.

Metabolic Profiling in Chinese Cabbage (Brassica rapa L. subsp. pekinensis) Cultivars Reveals that Glucosinolate Content Is Correlated with Carotenoid Content.

A total of 38 bioactive compounds, including glucosinolates, carotenoids, tocopherols, sterols, and policosanols, were characterized from nine varieties of Chinese cabbage (Brassica rapa L. subsp. pekinensis) to determine their phytochemical diversity and analyze their abundance relationships. The metabolite profiles were evaluated with principal component analysis (PCA), Pearson correlation analysis, and hierarchical clustering analysis (HCA). PCA and HCA identified two distinct varieties of Chinese cabbage (Cheonsangcheonha and Waldongcheonha) with higher levels of glucosinolates and carotenoids. Pairwise comparisons of the 38 metabolites were calculated using Pearson correlation coefficients. The HCA, which used the correlation coefficients, clustered metabolites that are derived from closely related biochemical pathways. Significant correlations were discovered between chlorophyll and carotenoids. Additionally, aliphatic glucosinolate and carotenoid levels were positively correlated. The Cheonsangcheonha and Waldongcheonha varieties appear to be good candidates for breeding because they have high glucosinolate and carotenoid levels.

Pathogenicity of Phytophthora capsici to Brassica Vegetable Crops and Biofumigation Cover Crops (Brassica spp.).

The soilborne oomycete Phytophthora capsici causes root, crown, and fruit rot of many vegetable crops in the Cucurbitaceae and Solanaceae families. P. capsici is a persistent problem in vegetable fields due to long-lived oospores that survive in soil and resist weathering and degradation. Vegetable crops in the Brassicaceae family have been considered nonhosts of P. capsici and are planted as rotational crops in infested fields. Brassica spp. are also grown as biofumigation cover crops to reduce inoculum levels of P. capsici and other soilborne pathogens, and this use has increased concurrent with restrictions on soil fumigation. Oriental mustard (Brassica juncea), oilseed rape (B. napus), and oilseed radish (Raphanus sativus var. oleiferus) contain high levels of glucosinolates and are widely recommended for biofumigation and as cover crops. The objective of this study was to evaluate vegetables and biofumigation cover crops in the Brassicaceae family for susceptibility to P. capsici. Brassica spp. used as vegetable crops and for biofumigation were grown in P. capsici-infested potting soil in the greenhouse and disease incidence and severity were recorded. In greenhouse trials, infection by the pathogen reduced the fresh weight of all Brassica spp. tested and resulted in plant death of 44% of plants of B. juncea 'Pacific Gold'. P. capsici isolates exhibited differences in virulence (P < 0.0001), and were reisolated from the roots of all Brassica spp. included in the study. The biofumigation cover crop Pacific Gold mustard may not reduce populations of P. capsici in soil and, instead, may sustain or increase pathogen levels. Further research is necessary to test this possibility under field conditions.

Preference and Performance of Hippodamia convergens (Coleoptera: Coccinellidae) and Chrysoperla carnea (Neuroptera: Chrysopidae) on Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae (Hemiptera: Aphididae) from Winter-Adapted Canola.

In the southern plains of the United States, winter-adapted canola (Brassica napus L.) is a recently introduced annual oilseed crop that has rapidly increased in hectares during the past 10 yr. Winter canola fields are infested annually with populations of Brevicoryne brassicae (L.) and Lipaphis erysimi (Kaltenbach), and these Brassica specialists are known to sequester plant volatiles from host plants, producing a chemical defense system against predators. Myzus persicae (Sulzer) is also common in winter canola fields, but as a generalist herbivore, does not sequester plant compounds. These three aphid species are expected to affect predator survival and development in very different ways. We conducted laboratory studies to 1) determine whether Hippodamia convergens (Guérin-Méneville) and Chrysoperla carnea (Stephens) larvae demonstrate feeding preferences among winter canola aphids and 2) describe the suitability of these prey species. Predators demonstrated no significant preference among prey, and each aphid species was suitable for predator survival to the adult stage. However, prey species significantly affected development times and adult weights of each predator species. Overall, predator development was delayed and surviving adults weighed less when provided with L. erysimi or B. brassicae, which sequestered high levels of indole glucosinolates from their host plants. Our results indicate that although common winter canola aphids were suitable prey for H. convergens and C. carnea, qualitative differences in nutritional suitability exist between Brassica-specialist aphids and the generalist M. persicae. These differences appear to be influenced by levels of sequestered plant compounds that are toxic to aphid predators.

Effect of industrial freezing on the stability of chemopreventive compounds in broccoli

Broccoli (Brassica oleracea L. var. Italica) is largely consumed all over the world and has a high economic importance. Likewise, broccoli contains high levels of glucosinolates, carotenoids and total phenols, which are related with the prevention of chronic diseases. The present project’s objective was to evaluate the effect of industrial freezing on the stability of bioactive molecules in seven commercial broccoli cultivars (Tlaloc®, Endurance®, Florapack®, Domador®, Steel®, Iron Man® and Avenger®). In general, industrial freezing increased the extractability of total glucosinolates, whereas total phenols remained constant in most broccoli cultivars. Likewise, broccoli subjected to industrial freezing showed higher levels of total carotenoids (∼60–300% higher) as compared with fresh broccoli. Results suggest that bioactive compounds in frozen broccoli would be more bioavailable than in raw.