BIOFUMIGANT COMPOUNDS RELEASED BY FIELD PENNYCRESS (Thlaspi arvense) SEEDMEAL

Isothiocyanates in medicine: A comprehensive review on phenylethyl-, allyl-, and benzyl-isothiocyanates

In recent years, isothiocyanates (ITCs), bioactive compounds primarily derived from Brassicaceae vegetables and herbs, have gained significant attention within the biomedical field due to their versatile biological effects. This comprehensive review provides an in-depth exploration of the therapeutic potential and individual biological mechanisms of the three specific ITCs phenylethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC), and benzyl isothiocyanate (BITC), as well as their collective impact within the formulation of ANGOCIN® Anti-Infekt N (Angocin). Angocin comprises horseradish root (Armoracia rusticanae radix, 80 mg) and nasturtium (Tropaeoli majoris herba, 200 mg) and is authorized for treating inflammatory diseases affecting the respiratory and urinary tract. The antimicrobial efficacy of this substance has been confirmed both in vitro and in various clinical trials, with its primary effectiveness attributed to ITCs. PEITC, AITC, and BITC exhibit a wide array of health benefits, including potent anti-inflammatory, antioxidant, and antimicrobial properties, along with noteworthy anticancer potentials. Moreover, we highlight their ability to modulate critical biochemical pathways, such as the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and signal transducer and activator of transcription (STAT) pathways, shedding light on their involvement in cellular apoptosis and their intricate role to guide immune responses.

Bioactivity of brassica seed meals and its compounds as ecofriendly larvicides against mosquitoes

Strategic, sustainable, and ecofriendly alternatives to chemical pesticides are needed to effectively control mosquitoes and reduce the incidence of their vectored diseases. We evaluated several Brassicaceae (mustard family) seed meals as sources of plant derived isothiocyanates produced from the enzymatic hydrolysis of biologically inactive glucosinolates for the control of Aedes aegypti (L., 1762). Five defatted seed meals (Brassica juncea (L) Czern., 1859, Lepidium sativum L., 1753, Sinapis alba L., 1753, Thlaspi arvense L., 1753, and Thlaspi arvense-heat inactivated and three major chemical products of enzymatic degradation (allyl isothiocyanate, benzyl isothiocyanate and 4-hydroxybenzyl isothiocyanate) were assayed to determine toxicity (LC₅₀) to Ae. aegypti larvae. All seed meals except the heat inactivated T. arvense were toxic to mosquito larvae. L. sativum seed meal was the most toxic treatment to larvae (LC₅₀ = 0.04 g/120 mL dH₂O) at the 24-h exposure. At the 72-h evaluation, the LC₅₀ values for B. juncea, S. alba and T. arvense seed meals were 0.05, 0.08 and 0.1 g/120 mL dH₂O, respectively. Synthetic benzyl isothiocyanate was more toxic to larvae 24-h post treatment (LC₅₀ = 5.29 ppm) compared with allyl isothiocyanate (LC₅₀ = 19.35 ppm) and 4-hydroxybenzyl isothiocyanate (LC₅₀ = 55.41 ppm). These results were consistent with the higher performance of the benzyl isothiocyanate producing L. sativum seed meal. Isothiocyanates produced from seed meals were more effective than the pure chemical compounds, based on calculated LC₅₀ rates. Using seed meal may provide an effective method of delivery for mosquito control. This is the first report evaluating the efficacy of five Brassicaceae seed meals and their major chemical constituent against mosquito larvae and demonstrates how natural compounds from Brassicaceae seed meals can serve as a promising ecofriendly larvicides to control mosquitoes.

Efficient Protoplast Isolation and DNA Transfection for Winter Oilseed Crops, Pennycress (Thlaspi arvense ) and Camelina (Camelina sativa )

Pennycress (Thlaspi arvense) and camelina (Camelina sativa) are nonfood winter oilseed crops that have the potential to contribute to sustainable biofuel production. However, undesired agronomic traits of pennycress and camelina currently hinder broad cultivation of these plants in the field. Recently, genome editing using the CRISPR-Cas technology has been applied to improve poor agronomic traits such as the weedy phenotype of pennycress and the oxidation susceptible lipid profile of camelina. In these works, the CRISPR reagents were introduced into the plants using the Agrobacterium-mediated floral dipping method. For accelerated domestication and value improvements of these winter oilseed crops, DNA-free genome editing platform and easy evaluation method of the CRISPR-Cas reagents are highly desirable. Cell wall-free protoplasts are great material to expand the use of gene engineering tools. In this chapter, we present a step-by-step guide to the mesophyll protoplast isolation from in vitro culture-grown pennycress and soil-grown camelina. The protocol also includes procedures for DNA transfection and protoplast viability test using fluorescein diacetate. With this protocol, we can isolate an average of 6 × 10⁶ cells from pennycress and 3 × 10⁶ cells from camelina per gram of fresh leaf tissues. Using a 7.3 kb plasmid DNA carrying green and red fluorescent protein marker genes, we can achieve an average transfection rate of 40% validated by flow cytometry for both plants.

Plant Growth Inhibitory Activities and Volatile Active Compounds of 53 Spices and Herbs

The inhibitory activities of the leachates and volatiles from 53 plant species (spices and herbs) were evaluated against lettuce (Lactuca sativa “Great Lakes 366”) seedling growth using the sandwich and dish pack methods, respectively. With the sandwich method, parsley (Petroselinum sativum) showed the strongest inhibitory effect on lettuce radicle growth (77%), followed by tarragon (Artemisia dracunculus) (72%). However, caraway (Carum carvi), dill (Anethum graveolens) (seed), laurel (Laurus nobilis), rosemary (Rosmarinus officinalis), and sage (Salvia officinalis) were the most inhibitory species (100% inhibition of lettuce radicle and hypocotyl growth inhibition at all distance wells) in the dish pack method. Cardamom (Elettaria cardamomum) and thyme (Thymus vulgaris) also showed strong inhibitory activity (100% for radicle and hypocotyl growth inhibition at all 41 and 58 mm distance wells). The headspace sampling and gas chromatography-mass spectrometry (GC-MS) analysis identified the main inhibitory active compounds as carvone in caraway and dill (seeds), 1,8-cineole in laurel and cardamom, and borneol in thyme. Both camphor and 1,8-cineole were detected in rosemary and sage, and the total activity evaluation showed that camphor was the major inhibitory compound in rosemary, although both compounds played equal roles in sage.

Identification of target genes and processes involved in erucic acid accumulation during seed development in the biodiesel feedstock Pennycress (Thlaspi arvense L.)

We studied erucic acid accumulation in the biodiesel feedstock Pennycress (Thlaspi arvense L.) as a first step towards the development of a sustainable strategy for biofuel production in the EU territory. To that end, two inbred Pennycress lines of European origin, "NASC" and "French," were cultivated in a controlled chamber and in experimental field plots, and their growth, seed production and seed oil characteristics analyzed. Differences in some agronomical traits like vernalization (winter-French versus spring-NASC), flowering time (delayed in the French line) and seed production (higher in the French line) were detected. Both lines showed a high amount (35-39%) of erucic acid (22:1^Δ13) in their seed oil. Biochemical characterization of the Pennycress seed oil indicated that TAG was the major reservoir of 22:1^Δ13. Incorporation of 22:1^Δ13 to TAG occurred very early during seed maturation, concomitant with a decrease of desaturase activity. This change in the acyl fluxes towards elongation was controlled by different genes at different levels. TaFAE1 gene, encoding the fatty acid elongase, seemed to be controlled at the transcriptional level with high expression at the early stages of seed development. On the contrary, the TaFAD2 gene that encodes the Δ12 fatty acid desaturase or TaDGAT1 that catalyzes TAG biosynthesis were controlled post-transcriptionally. TaWRI1, the master regulator of seed-oil biosynthesis, showed also high expression at the early stages of seed development. Our data identified genes and processes that might improve the biotechnological manipulation of Pennycress seeds for high-quality biodiesel production.

Metabolite fingerprinting of pennycress (Thlaspi arvense L.) embryos to assess active pathways during oil synthesis

Pennycress (Thlaspi arvense L.), a plant naturalized to North America, accumulates high levels of erucic acid in its seeds, which makes it a promising biodiesel and industrial crop. The main carbon sinks in pennycress embryos were found to be proteins, fatty acids, and cell wall, which respectively represented 38.5, 33.2, and 27.0% of the biomass at 21 days after pollination. Erucic acid reached a maximum of 36% of the total fatty acids. Together these results indicate that total oil and erucic acid contents could be increased to boost the economic competitiveness of this crop. Understanding the biochemical basis of oil synthesis in pennycress embryos is therefore timely and relevant to guide future breeding and/or metabolic engineering efforts. For this purpose, a combination of metabolomics approaches was conducted to assess the active biochemical pathways during oil synthesis. First, gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites highlighted three main families of compounds: organic acids, amino acids, and sugars/sugar alcohols. Secondly, these intermediates were quantified in developing pennycress embryos by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode. Finally, partitional clustering analysis grouped the intracellular metabolites that shared a similar pattern of accumulation over time into eight clusters. This study underlined that: (i) sucrose might be stored rather than cleaved into hexoses; (ii) glucose and glutamine would be the main sources of carbon and nitrogen, respectively; and (iii) glycolysis, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and the Calvin cycle were active in developing pennycress embryos.

New approaches to facilitate rapid domestication of a wild plant to an oilseed crop: example pennycress (Thlaspi arvense L.)

Oilseed crops are sources of oils and seed meal having a multitude of uses. While the domestication of soybean and rapeseed took extended periods of time, new genome-based techniques have ushered in an era where crop domestication can occur rapidly. One attractive target for rapid domestication is the winter annual plant Field Pennycress (Thlaspi arvense L.; pennycress; Brassicaceae). Pennycress grows widespread throughout temperate regions of the world and could serve as a winter oilseed-producing cover crop. If grown throughout the USA Midwest Corn Belt, for example, pennycress could produce as much as 840L/ha oils and 1470kg/ha press-cake annually on 16 million hectares of farmland currently left fallow during the fall through spring months. However, wild pennycress strains have inconsistent germination and stand establishment, un-optimized maturity for a given growth zone, suboptimal oils and meal quality for biofuels and food production, and significant harvest loss due to pod shatter. In this review, we describe the virtues and current shortcomings of pennycress and discuss how knowledge from studying Arabidopsis thaliana and other Brassicas, in combination with the advent of affordable next generation sequencing, can bring about the rapid domestication and improvement of pennycress and other crops.

Glucosinolates, myrosinase hydrolysis products, and flavonols found in rocket (Eruca sativa and Diplotaxis tenuifolia)

Rocket species have been shown to have very high concentrations of glucosinolates and flavonols, which have numerous positive health benefits with regular consumption. This review highlights how breeders and processors of rocket species can utilize genomic and phytochemical research to improve varieties and enhance the nutritive benefits to consumers. Plant breeders are increasingly looking to new technologies such as HPLC, UPLC, LC-MS, and GC-MS to screen populations for their phytochemical content to inform plant selections. This paper collates the research that has been conducted to date in rocket and summarizes all glucosinolate and flavonol compounds identified in the species. The paper emphasizes the importance of the broad screening of populations for phytochemicals and myrosinase degradation products, as well as unique traits that may be found in underutilized gene bank resources. This review also stresses that collaboration with industrial partners is becoming essential for long-term plant breeding goals through research.

De novo assembly of the pennycress (Thlaspi arvense) transcriptome provides tools for the development of a winter cover crop and biodiesel feedstock

Field pennycress (Thlaspi arvense L.) has potential as an oilseed crop that may be grown during fall (autumn) and winter months in the Midwestern United States and harvested in the early spring as a biodiesel feedstock. There has been little agronomic improvement in pennycress through traditional breeding. Recent advances in genomic technologies allow for the development of genomic tools to enable rapid improvements to be made through genomic assisted breeding. Here we report an annotated transcriptome assembly for pennycress. RNA was isolated from representative plant tissues, and 203 million unique Illumina RNA-seq reads were produced and used in the transcriptome assembly. The draft transcriptome assembly consists of 33 873 contigs with a mean length of 1242 bp. A global comparison of homology between the pennycress and Arabidopsis transcriptomes, along with four other Brassicaceae species, revealed a high level of global sequence conservation within the family. The final assembly was functionally annotated, allowing for the identification of putative genes controlling important agronomic traits such as flowering and glucosinolate metabolism. Identification of these genes leads to testable hypotheses concerning their conserved function and to rational strategies to improve agronomic properties in pennycress. Future work to characterize isoform variation between diverse pennycress lines and develop a draft genome sequence for pennycress will further direct trait improvement.

The dose-dependent influence of zinc and cadmium contamination of soil on their uptake and glucosinolate content in white cabbage (Brassica oleracea var. capitata f. alba)

The relationship between the ability to accumulate heavy metals (represented by Cd and Zn) and to synthesize bioactive compounds (represented by glucosinolates [GLS]) was investigated in two cabbage cultivars. Plants were grown in the greenhouse of a phytotron under controlled conditions in soils spiked with two different Zn or Cd concentrations. The measurements of Cd and Zn contents in soil and cabbage (leaf) samples were performed by atomic absorption spectroscopy, whereas GLS levels in cabbage were determined by high-performance liquid chromatography. The ranges of metal contents in soil were 80 to 450 mg/kg dry weight for Zn and 0.3 to 30 mg/kg dry weight for Cd, whereas the levels of accumulated Zn and Cd in cabbage amounted to 15 to 130 and 0.02 to 3 mg/kg dry weight, respectively. After initial symptoms of toxicity, during a later stage of growth, the plants exhibited very good tolerance to both metals. Enhanced biosynthesis of GLS was observed in a dose-dependent manner following exposure to the heavy metals. The GLS content in Zn-exposed cabbage rose from 3.2 to 12 µmol/g dry weight, and the corresponding values for Cd-treated plants were 3.5 to 10 µmol/g dry weight. Thus, the increased soil contamination by metals caused greater accumulation in cabbage, as well as stimulation of GLS biosynthesis. The results obtained point to the high phytoremediation and biofumigation potential of white cabbage.

Characterization of metabolite quantitative trait loci and metabolic networks that control glucosinolate concentration in the seeds and leaves of Brassica napus

• Glucosinolates are a major class of secondary metabolites found in the Brassicaceae, whose degradation products are proving to be increasingly important for human health and in crop protection. • The genetic and metabolic basis of glucosinolate accumulation was dissected through analysis of total glucosinolate concentration and its individual components in both leaves and seeds of a doubled-haploid (DH) mapping population of oilseed rape/canola (Brassica napus). • The quantitative trait loci (QTL) that had an effect on glucosinolate concentration in either or both of the organs were integrated, resulting in 105 metabolite QTL (mQTL). Pairwise correlations between individual glucosinolates and prior knowledge of the metabolic pathways involved in the biosynthesis of different glucosinolates allowed us to predict the function of genes underlying the mQTL. Moreover, this information allowed us to construct an advanced metabolic network and associated epistatic interactions responsible for the glucosinolate composition in both leaves and seeds of B. napus. • A number of previously unknown potential regulatory relationships involved in glucosinolate synthesis were identified and this study illustrates how genetic variation can affect a biochemical pathway.

Plant seeds as sources of potential industrial chemicals, pharmaceuticals, and pest control agents

Investigations of natural products isolated from seeds have resulted in a remarkable variety of compounds having unusual structures. Seeds of many plant species contain uncommon fatty acids and lipids, some of which have found uses in the cosmetic industry or as renewable (non-petroleum based) industrial raw materials. In addition to proteins and energy storage substances such as carbohydrates and lipids, seeds generally contain, or have the ability to produce, protective compounds that are active as plant growth regulators, fungicides, insecticides, and repellents of herbivores; seeds occasionally contain compounds that are toxic to most other organisms. These compounds may also be present in other plant parts, but often are found at higher concentrations in seeds. Other compounds of interest have been associated with plant-endophyte interactions that are of mutual benefit to both organisms. Tests of seed extracts for cytotoxic and antitumor activity, toxicity to insects, and relationships to several animal disease syndromes have been revealing. Examples of compounds isolated from plant seeds that have served as lead compounds for additional research, or that continue to be of interest to researchers in multiple areas, are reviewed.

The R2R3-MYB transcription factor HAG1/MYB28 is a regulator of methionine-derived glucosinolate biosynthesis in Arabidopsis thaliana

Methionine-derived glucosinolates belong to a class of plant secondary metabolites that serve as chemoprotective compounds in plant biotic defense reactions and also exhibit strong anticancerogenic properties beneficial to human health. In a screen for the trans-activation potential of various transcription factors toward glucosinolate biosynthetic genes, we could identify the HAG1 (HIGH ALIPHATIC GLUCOSINOLATE 1, also referred to as MYB28) gene as a positive regulator of aliphatic methionine-derived glucosinolates. The content of aliphatic glucosinolates as well as transcript levels of aliphatic glucosinolate biosynthetic genes were elevated in gain-of-function mutants and decreased in HAG1 RNAi knock-down mutants. Pro(HAG1):GUS expression analysis revealed strong HAG1 promoter activity in generative organs and mature leaves of A. thaliana plants, the main sites of accumulation of aliphatic glucosinolates. Mechanical stimuli such as touch or wounding transiently induced HAG1/MYB28 expression in inflorescences of flowering plants, and HAG1/MYB28 over-expression reduced insect performance as revealed by weight gain assays with the generalist lepidopteran herbivore Spodoptera exigua. Expression of HAG1/MYB28 was significantly induced by glucose, indicating a novel transcriptional regulatory mechanism for the integration of carbohydrate availability upon biotic challenge. We hypothesize that HAG1/MYB28 is a novel regulator of aliphatic glucosinolate biosynthesis that controls the response to biotic challenges.

Biology and biochemistry of glucosinolates

Glucosinolates are sulfur-rich, anionic natural products that upon hydrolysis by endogenous thioglucosidases called myrosinases produce several different products (e.g., isothiocyanates, thiocyanates, and nitriles). The hydrolysis products have many different biological activities, e.g., as defense compounds and attractants. For humans these compounds function as cancer-preventing agents, biopesticides, and flavor compounds. Since the completion of the Arabidopsis genome, glucosinolate research has made significant progress, resulting in near-complete elucidation of the core biosynthetic pathway, identification of the first regulators of the pathway, metabolic engineering of specific glucosinolate profiles to study function, as well as identification of evolutionary links to related pathways. Although much has been learned in recent years, much more awaits discovery before we fully understand how and why plants synthesize glucosinolates. This may enable us to more fully exploit the potential of these compounds in agriculture and medicine.