Changes in Content of Polyphenols and Ascorbic Acid in Leaves of White Cabbage after Pest Infestation

The Valorization of Wastes and Byproducts from Cruciferous Vegetables: A Review on the Potential Utilization of Cabbage, Cauliflower, and Broccoli Byproducts

The management of vegetable waste and byproducts is a global challenge in the agricultural industry. As a commonly consumed vegetable crop, cruciferous vegetables marked higher amounts of wastage during their supply chain processes, with a significant contribution from cabbage, cauliflower, and broccoli. Therefore, the sustainable and resource-efficient utilization of discarded materials is crucial. This review explores potential applications of cruciferous vegetable waste and byproducts, spotlighting cabbage, cauliflower, and broccoli in food, medicinal, and other industries. Their significance of being utilized in value-added applications is addressed, emphasizing important biomolecules, technologies involved in the valorization process, and future aspects of practical applications. Cabbage, cauliflower, and broccoli generate waste and low-processing byproducts, including leaves, stems, stalks, and rot. Most of them contain high-value biomolecules, including bioactive proteins and phytochemicals, glucosinolates, flavonoids, anthocyanins, carotenoids, and tocopherols. Interestingly, isothiocyanates, derived from glucosinolates, exhibit strong anti-inflammatory and anticancer activity through various interactions with cellular molecules and the modulation of key signaling pathways in cells. Therefore, these cruciferous-based residues can be valorized efficiently through various innovative extraction and biotransformation techniques, as well as employing different biorefinery approaches. This not only minimizes environmental impact but also contributes to the development of high-value-added products for food, medicinal, and other related industries.

Defense strategies and associated phytohormonal regulation in Brassica plants in response to chewing and sap-sucking insects

Plants have evolved distinct defense strategies in response to a diverse range of chewing and sucking insect herbivory. While chewing insect herbivores, exemplified by caterpillars and beetles, cause visible tissue damage and induce jasmonic acid (JA)-mediated defense responses, sucking insects, such as aphids and whiteflies, delicately tap into the phloem sap and elicit salicylic acid (SA)-mediated defense responses. This review aims to highlight the specificity of defense strategies in Brassica plants and associated underlying molecular mechanisms when challenged by herbivorous insects from different feeding guilds (i.e., chewing and sucking insects). To establish such an understanding in Brassica plants, the typical defense responses were categorized into physical, chemical, and metabolic adjustments. Further, the impact of contrasting feeding patterns on Brassica is discussed in context to unique biochemical and molecular modus operandi that governs the resistance against chewing and sucking insect pests. Grasping these interactions is crucial to developing innovative and targeted pest management approaches to ensure ecosystem sustainability and Brassica productivity.

Physiological and oxidative stress response of carrot (Daucus carota L.) to jumping plant-louse Bactericera trigonica Hodkinson (Hemiptera: Psylloidea) infestation

BACKGROUND

Carrot is an important vegetable crop grown worldwide. The major economic problem in carrot cultivation is yellow disease caused by Bactericera trigonica, which induces biotic stress and has the greatest impact on crop productivity. Comprehensive studies on the mechanism of carrot defense response to biotic stress caused by B. trigonica infestation have yet to be conducted.

METHODS

The changes in photosynthetic pigments, proline, TPC, H2O2 and MDA content, DPPH radical scavenging ability, and antioxidant enzyme activity of SOD, CAT, and POX in carrot leaves in response to insect sex (female and male), rapid response (during the first six hours), and long-term response to B. trigonica infestation were evaluated.

RESULTS

The results of our study strongly suggest that B. trigonica infestation causes significant changes in primary and secondary metabolism and oxidative status of carrot leaves. Photosynthetic pigment content, TPC, and DPPH and CAT activities were significantly reduced in carrot leaves in response to insect infestation. On the other hand, proline, H2O2 content, and the activity of the antioxidant enzymes superoxide dismutase and peroxidase were increased in carrot leaves after B. trigonica infestation. The results indicate that B. trigonica attenuates and delays the oxidative stress responses of carrot, allowing long-term feeding without visible changes in the plant. Carrot responded to long-term B. trigonica infestation with an increase in SOD and POX activity, suggesting that these enzymes may play a key role in plant defense mechanisms.

CONCLUSIONS

This is the first comprehensive study strongly suggesting that B. trigonica infestation causes significant changes in primary and secondary metabolism and an attenuated ROS defense response in carrot leaves that enables long-term insect feeding. The information provides new insights into the mechanisms of carrot protection against B. trigonica infestation.

Biochemical probing of phloem sap defensive traits in Brassica juncea-B. fruticulosa introgression lines following Lipaphis erysimi infestation

The lack of resistance to Lipaphis erysimi in cultivated Brassicas makes caused this pest highly devastating resulting in significant loss of rapeseed-mustard productivity in India. B. fruticulosa, a wild crucifer is known as an excellent source of resistance to L. erysimi. Therefore, we planned to assess defense associated biochemical alterations and molecular components of B. juncea-B. fruticulosa ILs to mustard aphid. Phenotypic assessment of ILs on the basis of aphid population per plant (APP) categorized genotypes into resistant (7.15-18.50 APP), moderately susceptible (42.29-53.33 APP) and susceptible (70.00-77.07 APP) genotypes. Mustard aphid infested minimally B. fruticulosa (0.80 APP) among tested genotypes. The maximum increase in catalase (CAT) activity was determined in B. fruticulosa and resistant ILs after 48 h (2.03 and 1.76-fold, respectively) and one week (2.98 and 1.79-fold, respectively) of mustard aphid infestation. The strong induction of CAT2 transcripts (19.25-fold) and CAT activity (5.88-fold) along with low aphid count in resistant IL, Ad4-64 (13.85 APP) suggested the pivotal role of CAT in resistance to mustard aphid. Guaiacol peroxidase (GPX) was significantly decreased following pest infestation at both infestation stages. The ascorbate content was highest in resistant IL, ADV-6RD (2.14-fold) after one week of aphid infestation. H2O2 content rapidly increased in B. juncea-B. fruticulosa derived lines after 48 h of aphid infestation. The negative and significant association between APP and CAT (- 0.56** and - 0.48*, respectively), glutathione (- 0.43* and - 0.40*, respectively), H2O2 (- 0.57** and - 0.43*, respectively) at both 48 h and one week infestation stages signified their role in deterring mustard aphid infestation. The positive and significant association between total sugars (0.33* at 7 DPI), reducing sugars (0.33* at 7 DPI), sucrose (0.36** at 48 h) and APP indicated that higher the sugars content, higher will be mustard aphid infestation in B. juncea derived ILs. The information being generated and key candidates (CAT2, ascorbate and H2O2) being identified may help in effective deployment of B. fruticulosa resistance in mustard breeding.

Different responses of two maize cultivars to Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae infestation provide insights into their differences in resistance

Spodoptera frugiperda (Lepidoptera: Noctuidae), a pest with an amazing appetite, damages many crops and causes great losses, especially maize. Understanding the differences in different maize cultivars' responses to S. frugiperda infestation is very important for revealing the mechanisms involved in the resistance of maize plants to S. frugiperda. In this study, a comparative analysis of two maize cultivars, the common cultivar 'ZD958' and the sweet cultivar 'JG218', was used to investigate their physico-biochemical responses to S. frugiperda infestation by a pot experiment. The results showed that the enzymatic and non-enzymatic defense responses of maize seedlings were rapidly induced by S. frugiperda. Frist, the hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents of infested maize leaves were significantly increased and then decreased to the level of the control. Furthermore, compared with the control leaves, the puncture force values and the total phenolics, total flavonoids, and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one contents of infested leaves were significantly increased within a certain time. The superoxide dismutase and peroxidase activities of infested leaves were significantly increased in a certain period of time, while the catalase activities decreased significantly and then increased to the control level. The jasmonic acid (JA) levels of infested leaves were significantly improved, whereas the salicylic acid and abscisic acid levels changed less. Signaling genes associated with phytohormones and defensive substances including PAL4, CHS6, BX12, LOX1, and NCED9 were significantly induced at certain time points, especially LOX1. Most of these parameters changed greater in JG218 than in ZD958. Moreover, the larvae bioassay showed that S. frugiperda larvae weighed more on JG218 leaves than those on ZD958 leaves. These results suggested that JG218 was more susceptible to S. frugiperda than ZD958. Our findings will make it easier to develop strategies for controlling S. frugiperda for sustainable maize production and breeding of new maize cultivars with increased resistance to herbivores.

Root Colonization by Fungal Entomopathogen Systemically Primes Belowground Plant Defense against Cabbage Root Fly

Entomopathogenic fungi infect insects via spores but also live inside plant tissues as endophytes. Frequently, colonization by entomopathogens provides plants with increased resistance against insects, but the mechanisms are little understood. This study investigated direct, local, and systemic root-mediated interactions between isolates of the fungus Metarhizium brunneum and larvae of the cabbage root fly (CRF) Delia radicum attacking Brassica napus plants. All fungal isolates infected CRF when conidia were present in the soil, leading to 43–93% mortality. Locally, root-associated M. brunneum isolates reduced herbivore damage by 10–20% and in three out of five isolates caused significant insect mortality due to plant-mediated and/or direct effects. A split-root experiment with isolate Gd12 also demonstrated systemic plant resistance with significantly reduced root collar damage by CRF. LC-MS analyses showed that fungal root colonization did not induce changes in phytohormones, while herbivory increased jasmonic acid (JA) and glucosinolate concentrations. Proteinase inhibitor gene expression was also increased. Fungal colonization, however, primed herbivore-induced JA and the expression of the JA-responsive plant defensin 1.2 (PDF1.2) gene. We conclude that root-associated M. brunneum benefits plant health through multiple mechanisms, such as the direct infection of insects, as well as the local and systemic priming of the JA pathway.

Advances in Plant Metabolomics and Its Applications in Stress and Single-Cell Biology

In the past two decades, the post-genomic era envisaged high-throughput technologies, resulting in more species with available genome sequences. In-depth multi-omics approaches have evolved to integrate cellular processes at various levels into a systems biology knowledge base. Metabolomics plays a crucial role in molecular networking to bridge the gaps between genotypes and phenotypes. However, the greater complexity of metabolites with diverse chemical and physical properties has limited the advances in plant metabolomics. For several years, applications of liquid/gas chromatography (LC/GC)-mass spectrometry (MS) and nuclear magnetic resonance (NMR) have been constantly developed. Recently, ion mobility spectrometry (IMS)-MS has shown utility in resolving isomeric and isobaric metabolites. Both MS and NMR combined metabolomics significantly increased the identification and quantification of metabolites in an untargeted and targeted manner. Thus, hyphenated metabolomics tools will narrow the gap between the number of metabolite features and the identified metabolites. Metabolites change in response to environmental conditions, including biotic and abiotic stress factors. The spatial distribution of metabolites across different organs, tissues, cells and cellular compartments is a trending research area in metabolomics. Herein, we review recent technological advancements in metabolomics and their applications in understanding plant stress biology and different levels of spatial organization. In addition, we discuss the opportunities and challenges in multiple stress interactions, multi-omics, and single-cell metabolomics.

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.

Defensive capabilities of contrasting sorghum genotypes against Atherigona soccata (Rondani) infestation

Plants are equipped with a wide range of defensive mechanisms such as morphophysiological, biochemical, molecular, and hormonal signaling for protecting against insect-pest infestation. The infestation of a devastating pest shoot fly [Atherigona soccata (Rodani)] at seedling stage causes huge loss of sorghum crop productivity. In morphophysiological screening ICSV700, ICSV705, and IS18551 have been categorized as resistant, PSC-4 moderately resistant, SL-44 and SWARNA as susceptible. The present study focused on the role of defensive gene expression and its products viz: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), polyphenol oxidase (PPO), phenyl alanine ammonia lyase (PAL), responsive enzymes, and metabolites restoring redox status in sorghum plants against shoot fly infestation. In both leaf and stem tissue of sorghum genotypes, shoot fly infestation induced SOD, APX, DHAR, GR, PAL, and PPO activities while CAT activity was significantly declined at 15 and 21 days after emergence (DAE). IS18551 with resistant behavior showed upregulation of SOD, GR, APX, and DHAR along with accumulation of ascorbate, glutathione enhancing redox status of the plant during shoot fly infestation at later stage of infestation. While SWARNA with susceptible response exhibited enhanced activity of phenylpropanoid pathway enzymes PAL and PPO which in turn increased the levels of secondary metabolites like o-dihydroxyphenol and other phenols deterring the insect to attack the plant. The qRT-PCR data predicted that stress-responsive genes were initially unregulated in SWARNA; however, at 21 DAE, multifold higher expression of SOD, CAT, APX, and PPO (24.8-, 37.2-, 21.7-, and 17.9-fold respectively) in 1S18551 indicates the resistance behavior of this genotype against insect infestation owing to sustainable development capability.

Seaweed Extract Improves Lagenaria siceraria Young Shoot Production, Mineral Profile and Functional Quality

Vegetable landraces represent the main source of biodiversity in Sicily. Lagenaria siceraria is appreciated by Southern Mediterranean consumers for its immature fruits and young shoots. Plant-based biostimulants supply, such as seaweed extract (SwE), is a contemporary and green agricultural practice applied to ameliorate the yield and quality of vegetables. However, there are no studies concerning the effects of SwE on L. siceraria. The current study evaluated the effects of SwE foliar application (0 or 3 mL L−1) on five L. siceraria landraces (G1, G2, G3, G4 and G5) grown in greenhouses. Growth traits, first female flower emission, fruit yield, young shoot yield, fruit firmness, young shoot nitrogen use efficiency (NUEys) and specific young shoot quality parameters, such as soluble solids content (SSC), mineral profile, ascorbic acid, and polyphenols, were appraised. Plant height and number of leaves at 10, 20 and 30 days after transplant (DAT) were significantly higher in plants treated with SwE as compared with untreated plants. Treating plants with SwE increased marketable fruit yield, fruit mean mass, young shoot yield and number of young shoots by 14.4%, 15.0%, 22.2%, 32.4%, and 32.0%, respectively as compared with untreated plants. Relevant increments were also recorded for NUEys, P, K, Ca, Mg, ascorbic acid and polyphenols concentration. SwE application did not significantly affect total yield and SSC. Furthermore, SwE treated plants produced a lower number of marketable fruits than non-treated plants. The present study showed that SwE at 3 mL L−1 can fruitfully enhance crop performance, young shoot yield and quality of L. siceraria.

Comprehensive Evaluation of Amino Acids and Polyphenols in 69 Varieties of Green Cabbage (Brassica oleracea L. var. capitata L.) Based on Multivariate Statistical Analysis

The biological activities of the primary metabolites and secondary metabolites of 69 green cabbage varieties were tested. The LC-MS detection method was used to determine the content of 19 free amino acids (lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, arginine, asparagine, glycine, proline, tyrosine, glutamine, alanine, aspartic acid, serine, and glutamate). The content of 10 polyphenols (chlorogenic acid, gallic acid, 4-coumaric acid, ferulic acid, gentisic acid, cymarin, erucic acid, benzoic acid, rutin, and kaempferol) was determined by the HPLC detection method. Considering the complexity of the data obtained, variance analysis, diversity analysis, correlation analysis, hierarchical cluster analysis (HCA), and principal component analysis (PCA) were used to process and correlate amino acid or polyphenol data, respectively. The results showed that there were significant differences between the different amino acids and polyphenols of the 69 cabbage varieties. The most abundant amino acids and polyphenols were Glu and rutin, respectively. Both amino acids and polyphenols had a high genetic diversity, and multiple groups of significant or extremely significant correlations. The 69 cabbage varieties were divided into two groups, according to 19 amino acid indexes, by PCA. Among them, seven varieties with high amino acid content all fell into the fourth quadrant. The HCA of amino acids also supports this view. Based on 10 polyphenols, the 69 cabbage varieties were divided into two groups by HCA. Based on 29 indexes of amino acids and polyphenols, 69 cabbage varieties were evaluated and ranked by PCA. Therefore, in this study, cabbage varieties were classified in accordance with the level of amino acids and polyphenols, which provided a theoretical basis for the genetic improvement of nutritional quality in cabbage.

The Influence of Locality on Phenolic Profile and Antioxidant Capacity of Bud Extracts

Gemmotherapy represents the most recent therapeutic technique that uses the properties of extracts from fresh meristematic plant tissues, mainly buds and sprouts, by macerating them in ethanol and glycerol. The harvesting time and the location can significantly affect the chemical composition of the buds. Therefore, this work aimed to point out the possible variability in the phenolic content and the antioxidant potential of extracts prepared from commonly grown trees in the Czech Republic. Extracts from buds collected during autumn and spring in three different localities were analysed using UHPLC-MS (ultra-high-pressure liquid chromatography) for the phenols profile. Five tests assays were used for the evaluation of the extract antioxidant potential. The sampling time positively affected the content of total phenols, flavonoids, and phenolic acids. The increased levels of total phenols and flavonoids in localities with high and medium pollution may be the result of the higher levels of NO and SO_2, the main air pollutants. However, surprisingly, the content of phenolic acid showed the highest values in the area with the lowest pollution. The results of antioxidant tests did not completely correlate with the levels of phenolic metabolites, which may be due to the involvement of other active molecules (e.g., ascorbate, tocopherol, or proline) in the antioxidant machinery.

Fullerenol changes metabolite responses differently depending on the iron status of cucumber plants

The unique properties of carbon-based nanomaterials, including fullerenol, have attracted great interest in agricultural and environmental applications. Iron (Fe) is an essential micronutrient for major metabolic processes, for which a shortage causes chlorosis and reduces the yield of many crops cultivated worldwide. In the current study, the metabolic responses of Cucumis sativus (a Strategy I plant) to fullerenol treatments were investigated depending on the Fe status of plants. Cucumber plants were grown hydroponically, either with [+FeII (ferrous) and +FeIII (ferric)] or in Fe-free (-FeII and -FeIII) nutrient solution, with (+F) or without (-F) a fullerenol supply. Iron species-dependent effects were observed in either Fe-fed or Fe-starved plants, with alteration of metabolites involved in the metabolism of carbohydrates, amino acids, organic acids, lipophilic compounds. Metabolic perturbations triggered by fullerenol in the FeIII-treated plants were in the opposite kind from those in the FeII-treated plants. Whereas in the FeIII-fed plants, fullerenol activated the metabolisation of carbohydrates and amino acids, in the FeII-fed plants, fullerenol activated the metabolisation of lipophilic compounds and repressed the metabolisation of carbohydrates and amino acids. In FeIII-deficient plants, fullerenol stimulated the metabolism of C3 carboxylates and lipophilic compounds while repressing the metabolism of amino acids, hexoses and dicarboxylates, while in FeII-deficient plants, activations of the metabolism of amino acids and dicarboxylates and repression of sterol metabolism by fullerenol were observed. The results indicated that the valence state of Fe sources is of importance for re-programming metabolome responses in cucumber to fullerenol either in Fe-sufficient or Fe-deficient conditions. These investigations are significant for understanding fullerenol interactions and risk assessment in plants with different Fe statuses.

The Interactive Effect of Elevated CO2 and Herbivores on the Nitrogen-Fixing Plant Alnus incana ssp. rugosa

Many studies have found that future predicted CO2 levels can increase plant mass but dilute N content in leaves, impacting antiherbivore compounds. Nitrogen-fixing plants may balance their leaf C:N ratio under elevated CO2, counteracting this dilution effect. However, we know little of how plants respond to herbivores at the higher CO2 levels that occurred when nitrogen-fixing plants first evolved. We grew Alnus incana ssp. rugosa was grown at 400, 800, or 1600 ppm CO2 in soil collected from the field, inoculated with Frankia and exposed to herbivores (Orgyia leucostigma). Elevated CO2 increased nodulated plant biomass and stimulated the nitrogen fixation rate in the early growth stage. However, nitrogen-fixing plants were not able to balance their C:N ratio under elevated CO2 after growing for 19 weeks. When plants were grown at 400 and 1600 ppm CO2, herbivores preferred to feed on leaves of nodulated plants. At 800 ppm CO2, nodulated plants accumulated more total phenolic compounds in response to herbivore damage than plants in the non-Frankia and non-herbivore treatments. Our results suggest that plant leaf defence, not leaf nutritional content, is the dominant driver of herbivory and nitrogen-fixing plants have limited ability to balance C:N ratios at elevated CO2 in natural soil.

The Multifunctional Roles of Polyphenols in Plant-Herbivore Interactions

There is no argument to the fact that insect herbivores cause significant losses to plant productivity in both natural and agricultural ecosystems. To counter this continuous onslaught, plants have evolved a suite of direct and indirect, constitutive and induced, chemical and physical defenses, and secondary metabolites are a key group that facilitates these defenses. Polyphenols—widely distributed in flowering plants—are the major group of such biologically active secondary metabolites. Recent advances in analytical chemistry and metabolomics have provided an opportunity to dig deep into extraction and quantification of plant-based natural products with insecticidal/insect deterrent activity, a potential sustainable pest management strategy. However, we currently lack an updated review of their multifunctional roles in insect-plant interactions, especially focusing on their insect deterrent or antifeedant properties. This review focuses on the role of polyphenols in plant-insect interactions and plant defenses including their structure, induction, regulation, and their anti-feeding and toxicity effects. Details on mechanisms underlying these interactions and localization of these compounds are discussed in the context of insect-plant interactions, current findings, and potential avenues for future research in this area.

Morphophysiological and biochemical attributes influence intra-genotypic preference of shoot fly [Atherigona soccata (Rondani)] among sorghum genotypes

Shoot fly [Atherigona soccata (Rondani)] is a destructive pest of sorghum at the seedling stage and causes huge losses to grain yield and green fodder. The host-plant resistance mechanism is the best approach to reduce the attack of insects in plants. The damage parameters, morphophysiological traits, and biochemical metabolites had been investigated in the leaves and stem of contrasting sorghum genotypes, viz., resistant (IS18551, ICSV705, ICSV700), moderately resistant (PSC-4), and susceptible (SWARNA and SL-44) at 15 and 21 days after emergence (DAE) against shoot fly infestation. The resistant genotypes recorded lowest shoot fly oviposition and incidence (0.3-0.7 eggs plant^-1 and 10-15%) than the susceptible genotypes (2.4-3.0 eggs plant^-1 and 70-80%), respectively. The susceptible genotype SWARNA recorded 50% and 80% higher deadheart formation than the resistant genotype IS18551 at 15 and 21 DAE, respectively. Resistant genotypes exhibited higher trichome density at adaxial and abaxial part of leaf (118-145 and 106-131) with pink colored leaf sheath (scale 1.50-3.25), glossy leaves (scale1.00-1.25), and lower leaf surface wetness (scale1.25-2.00) compared with susceptible genotype with 49.3-73.3 and 25.3-64.0, scale 2.50-4.00, scale 2.75-3.50, and scale 3.25-4.25 for the respective parameters. Another defense response of sorghum toward the insect attack was modulation of plant metabolism. The infested genotypes responded to insect attack by upregulation of total soluble sugar, total phenol, prussic acid, and chlorophyll content by 1.2-2.1-fold, 1.5-2.0-fold, 1.2-1.3-fold, and 1.2-3.9-fold with more induction in susceptible genotypes at 21 DAE. On the whole, the present study indicates that morphophysiological and biochemical attributes contribute toward the resistance mechanism in sorghum against shoot fly infestation.

Ethylene Induction of Non-Enzymatic Metabolic Antioxidants in Matricaria chamomilla

Phytochemical investigations of Matricaria chamomilla L. (Asteraceae) stated the presence of several compounds with an established therapeutic and antioxidant potential. The chamomile non-enzymatic antioxidant system includes low molecular mass compounds, mainly polyphenols such as cinnamic, hydroxybenzoic and chlorogenic acids, flavonoids and coumarins. The objective of this work was to evaluate the role of the non-enzymatic antioxidant system after stimulation by ethylene in tetraploid chamomile plants. Seven days of ethylene treatment significantly increased the activity of phenylalanine ammonia-lyase, which influenced the biosynthesis of protective polyphenols in the first step of their biosynthetic pathway. Subsequently, considerable enhanced levels of phenolic metabolites with a substantial antioxidant effect (syringic, vanillic and caffeic acid, 1,5-dicaffeoylquinic acid, quercetin, luteolin, daphnin, and herniarin) were determined by HPLC-DAD-MS. The minimal information on the chlorogenic acids function in chamomile led to the isolation and identification of 5-O-feruloylquinic acid. It is accumulated during normal conditions, but after the excessive effect of abiotic stress, its level significantly decreases and levels of other caffeoylquinic acids enhance. Our results suggest that ethephon may act as a stimulant of the production of pharmaceutically important non-enzymatic antioxidants in chamomile leaves and thus, lead to an overall change in phytochemical content and therapeutic effects of chamomile plants, as well.

Ascorbic Acid-The Little-Known Antioxidant in Woody Plants

Reactive oxygen species (ROS) are constantly produced by metabolically active plant cells. The concentration of ROS may determine their role, e.g., they may participate in signal transduction or cause oxidative damage to various cellular components. To ensure cellular homeostasis and minimize the negative effects of excess ROS, plant cells have evolved a complex antioxidant system, which includes ascorbic acid (AsA). AsA is a multifunctional metabolite with strong reducing properties that allows the neutralization of ROS and the reduction of molecules oxidized by ROS in cooperation with glutathione in the Foyer-Halliwell-Asada cycle. Antioxidant enzymes involved in AsA oxidation and reduction switches evolved uniquely in plants. Most experiments concerning the role of AsA have been performed on herbaceous plants. In addition to extending our understanding of this role in additional taxa, fundamental knowledge of the complex life cycle stages of woody plants, including their development and response to environmental factors, will enhance their breeding and amend their protection. Thus, the role of AsA in woody plants compared to that in nonwoody plants is the focus of this paper. The role of AsA in woody plants has been studied for nearly 20 years. Studies have demonstrated that AsA is important for the growth and development of woody plants. Substantial changes in AsA levels, as well as reduction and oxidation switches, have been reported in various physiological processes and transitions described mainly in leaves, fruits, buds, and seeds. Evidently, AsA exhibits a dual role in the photoprotection of the photosynthetic apparatus in woody plants, which are the most important scavengers of ozone. AsA is associated with proper seed production and, thus, woody plant reproduction. Similarly, an important function of AsA is described under drought, salinity, temperature, light stress, and biotic stress. This report emphasizes the involvement of AsA in the ecological advantages, such as nutrition recycling due to leaf senescence, of trees and shrubs compared to nonwoody plants.