No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The form, dose, and method of application of vermicompost differentiate the phenylpropene biosynthesis in the peltate glandular trichomes of methylchavicol chemotype of Ocimum basilicum L.
Abstract
Peltate glandular trichomes (PGTs) in basil (Ocimum basilicum L.) are ideal for studying phenylpropanoid metabolism, as they allow for the elimination of the effects of primary plant metabolism. In this study, we aimed to investigate the effects of 0, 10%, and 25% doses of both solid and tea forms of vermicompost on phenylpropanoid metabolism in PGTs of the methylchavicol chemotype of basil. The experiment based on the analysis of the gene expression (PAL, 4CL, EGS, EOMT, CVOMT) and the accumulation of phenylpropene (eugenol, chavicol, methyleugenol, methylchavicol) in PGTs after vermicompost treatment. Our results showed that the
application of solid vermicompost (SV) to the root zone of basil at 10% and 25% significantly reduced the expression of EOMT and CVOMT to below 0.1 from 2.43 and 3.85, respectively. The application of 10% solid vermicompost (SV) to basil soil resulted in a decrease in methyleugenol and methylchavicol accumulation approximately by 50% and 52%, respectively. Further application of 25% (SV) resulted in a total decrease of approximately 76% and 51% in methyleugenol and methylchavicol accumulation, respectively. Application of 10% vermicompost tea (VT) to basil leaves resulted in a significant increase in chavicol accumulation (243%) and methyleugenol accumulation (613%) in basil essential oil, as well as upregulation of EOMT and CVOMT gene expression approximately by 391-fold and 1,155-fold, respectively, compared to control plants. Furthermore, application of 25% VT resulted in a significant increase in eugenol accumulation (665%) and methylchavicol accumulation (56%), as well as downregulation of EOMT and CVOMT gene expression approximately by 31-fold and 9-fold, respectively, compared to control plants. These findings suggest that VT application can modulate the
accumulation of important phenylpropenes in basil through regulation of gene expression. In addition, the use of vermicompost tea has been shown to significantly enhance the levels of phenylpropenes in basil, which are important contributors to the herb’s aroma and antimicrobial activity. This suggests that the application of VT
can play a crucial role in determining the quality of basil in terms of its secondary metabolites, making it a valuable tool in phytoremediation practices. Overall, our results demonstrate the effectiveness of vermicompost on phenylpropene biosynthesis and the utility of PGTs composed of a single cell type for the study of secondary metabolic processes in plants.
... The chemical complexity of humic acids (HAs) has made it difficult to identify auxin-like molecules that cause biostimulant effects, leading researchers to determine that organic fractions containing HAs have auxin-like properties [33]. Vermicompost also contains soluble nutrients, free enzymes, a wide range of microorganisms, and water-soluble phenols that can easily diffuse into the water during the vermicompost tea production [31,34]. ...
... SV applications increased methylated phenylpropenes in methyleugenol chemotype PGTs, while VT applications led to a decrease. Conversely, SV applications caused a decrease and VT applications resulted to an increase in methylchavicol chemotype PGTs according to the results of a previous research [34]. These varied responses underscore chemotype differences' role in shaping basil plants' treatment reactions. ...
This research delves into phenylpropanoid metabolism, focusing on phenylpropene biosynthesis in the methyleugenol chemotype of basil (Ocimum basilicum L.). We isolated peltate glandular trichomes (PGTs) from basil leaves to eliminate primary metabolic influences, offering a unique perspective into these complex processes. Vermicompost, chosen for its eco-friendly composition and superiority in invigorating phenylpropanoid metabolism. In this study, we investigated the impacts of solid and tea-form vermicompost applications at 0%, 10%, and 25% doses on the methyleugenol chemotype of basil, focusing on the expression levels of PAL, 4CL, EGS, EOMT, and CVOMT genes and phenylpropene accumulation in the peltate glandular trichomes. Results showed that 10% solid vermicompost (SV) application increased 4CL expression level at 236%, while 25% SV application further enhanced EOMT and CVOMT expressions to towering values by 7,494-fold and 19,643-fold, respectively. SV applications did not significantly impact eugenol accumulation but suppressed chavicol biosynthesis. Methyleugenol and methylchavicol accumulation rose in a dose-dependent manner, with significant increases observed in the 25% SV application. A positive correlation was found between CVOMT expression and accumulation rates of methyleugenol and methylchavicol phenylpropenes following SV applications. Conversely, vermicompost tea (VT) applications led to mixed gene expression patterns and reduced eugenol and methyleugenol ratios in peltate glandular trichomes compared to control. In summary, the notably high gene expressions observed in the results of our preliminary study offer a new perspective in the field of phenylpropanoid metabolism. This underscores the value of utilizing single-cell type PGTs for examining secondary metabolic pathways in plants and demonstrates the impact of vermicompost on phenylpropene production.
... Basil is cultivated for its essential oil because it is used as odorizer and flavorant in perfumery and the food industry as well as in the pharmaceutical industry [16][17][18]. In traditional medicine, it has been used in folk medicine to treat coughs, headaches, diarrhea, warts, constipation, and kidney dysfunction, as well as to promote digestion and to stimulate appetite [19,20] due to the fact that it contains secondary metabolites, ...
Knowledge about the pharmacological benefits of different seeds is an important factor for the cultivation and application of medicinal herbs and plants. The seeds of medicinal plants are stores of valuable and active secondary metabolites that have been commercially and economically beneficial and helpful for medicine and pharmacy. The major parameter of reproduction and the preservation of plants are seeds, which have a functional role in the distribution and establishment of plants in different regions. Five important seeds that have tremendous medicinal and pharmacological benefits are anise, basil, borage, cilantro, and chamomile. Anise seed is used as a spice, either whole or ground, and its essential oil and extract are also obtained from the seeds. Basil seeds have a long history of usage in Chinese and Ayurvedic medicine, and they are a good source of minerals, are high in fiber (including pectin), and are rich is flavonoids and other polyphenols. Borage seed oil is used for skin disorders, such as seborrheic dermatitis, atopic dermatitis, and neurodermatitis. Coriander is an annual herb that is part of the Apiaceae family, and the seeds are rich in iron, zinc, copper, and essential minerals, which can decrease bad cholesterol and improve good cholesterol in the body. Chamomile can be considered for the treatment of insomnia, hemorrhoids, anxiety, and diarrhea, and it may help with wound healing and skin irritation.
Heat treatment of vermicompost and cow manure is mandated before their use as fertilizers to address the risk of pathogenicity in vermicompost derived from cow manure. While vermicomposting under mesophilic conditions does not significantly reduce microorganisms or degrade enzymes and proteins, organic matter passing through the earthworm's digestive system is effectively composted and sterilized. This study focused on cow manure and subjected it to three heat treatments: 25 °C (HT1), 70 °C for 1 hour (HT2), and 121 °C at 1.5 atm for 15 minutes (HT3). We assessed these treatments over five incubation periods (0, 7, 15, 30, and 45 days) on earthworm (Eisenia fetida L.) biomass, juvenile counts, and cocoon production. The results showed that all earthworms in HT3 died at the second incubation, while the HT1 and HT2 groups survived. Cocoon counts in HT1 and HT2 increased with each period (P
Clove basil (Ocimum gratissimum L.) is an aromatic herb and grown across tropical and sub tropical parts of the world. It is grown in disturbed area and cultivated due to broad-leaves among basils. It is rich in essential oil and extensively used in traditional medicines of Asia and Africa. Flower bud of Syzygium aromaticum L. and bark from Cinnamomum verum L. are general source of natural eugenol production. Cost of cultivation and commercial extraction of eugenol from these trees are very high and time taking due to long gestation period essential for crop maturity and harvesting. It induced an idea for evaluation of available elite accessions rich in herbage and quality components. The experiment was conducted in Kharif 2021 in RBD design with seven replications. Three diverse accessions were observed significant variation for leaf morphology, quantitative, qualitative and molecular parameters under evaluation. Essential oils of the three accession were found to be rich in eugenol. Among the three accessions α-bergamotene and β-copanene were found to be the other major compounds in DOGr-1 and DOGr-2, while α-bergamotene and caryophyllene were found to be the other major compounds in DOGr-3. Maximum yield in terms of herbage, essential oil and eugenol content was observed in DOGr-3. DOGr-3 was found to be unique and diverse for phenotypic characters, yield contributing traits, chemical content and genetic makeup.
Despite scientific evidence supporting the biostimulant activity of protein hydrolysates (PHs) derived from vegetal or animal sources, the morpho-physiological and biochemical mechanisms underlying the biostimulant action of PHs from plant biomass or animal by-products are still poorly explored. Accordingly, we performed a greenhouse experiment for assessing the morphological, physiological and biochemical responses of sweet basil (Ocimum basilicum L.) to three nitrogen equivalent rates (0.05, 0.15, and 0.25 g N/kg) of an animal-derived protein hydrolysate (A-PH) and a vegetal-derived protein hydrolysate (V-PH). The V-PH and A-PH applications determined a quadratic-dose response regarding the number and area of leaves and the shoot fresh and dry weight, with the best results obtained using V-PH at the N equivalent rates of 0.05 and 0.15 g N/kg. Improvement of shoot fresh weight with V-PH foliar application at the rate of 0.15 g N/kg was associated with a higher leaf CO 2 assimilation and water use efficiency, with a concomitant higher uptake and translocation of K, Mg, and S in leaf tissue. The excessive accumulation of Na, Cl, and some amino acids (e.g., proline) under A-PH applications above 0.05 g N/kg induced a rapid decrease in plant photosynthetic performance, growth, and biomass production. The plants treated with A-PH at a higher dosage appeared to activate an alternative pathway involving the synthesis of alanine and GABA for storing excess ammonia, buffering cytoplasmic acidosis, and counteracting the negative effects of Na and Cl at toxic levels. The above findings demonstrated the potential benefits of protein hydrolysate application in agriculture, especially of vegetal-derived PHs, and highlighted the need to understand dose-dependent effects in order to optimize crop response.
Environmental stresses might alter the activity of antioxidant defense system and both quantity and quality of the essential oil constituents in aromatic plants. In the current study, a greenhouse experiment was designed to assess the influence of cold stress on total phenolic (TPC) and flavonoid contents (TFC), DPPH radical scavenging, antioxidant and phenylalanine ammonia-lyase (PAL) enzymes activity and content of phenylpropanoid compounds in Ocimum basilicum L. The genes expression levels of chavicol O-methyl transferase (CVOMT), cinnamate 4-hydroxylase (C4H), eugenol synthase 1 (EGS1) and eugenol O-methyl transferase (EOMT) were also investigated. Results revealed the highest TPC, TFC and DPPH at 4 °C for 12 h. Positive significant correlation was observed between TFC and DPPH, as well as TPC and PAL enzyme activity. The highest activity of superoxide dismutase and guaiacol peroxidase was recorded in 4 °C for 48 h, while this treatment caused the highest reduction in the activities of ascorbate peroxidase and catalase. In plants exposed to 10 °C for 48 h, the contents of methyleugenol and methylchavicol was positively associated with the expression levels of EGS1 and EOMT. A positive correlation was also found between C4H expression and eugenol, methyleugenol and methylchavicol contents under 4 °C for 12 h.
Sweet basil is one of the most important culinary herbs. Currently, its production is carried out mainly in accordance with conventional agriculture. However, its cultivation in organic systems seems to be better adjusted to consumer demands connected with the lack of pesticide residues in foods and their safety. In the present study, two methods of basil cultivation in organic farming system were applied, i.e., in the open air and under foil tunnels. During the experiment, in central European climatic conditions, it was possible to obtain four successive cuts of herb. The herb was subjected to chemical analysis, including determination of the content of essential oil, phenolic compounds, and chlorophylls. Gas chromatography coupled with mass spectrometry (GC–MS) and flame ionization detector (GC-FID) analysis of the essential oil was performed, whereas the fresh herb was subjected to sensory analysis. The cumulative mass of fresh herb was distinctly higher in the cultivation under foil tunnels (44.7 kg∙10 m−2) in comparison to the open field (24.7 kg∙10 m−2). The content of essential oil, flavonoids, and phenolic acids was also higher in the raw material collected from plants grown under foil tunnels (0.81, 0.36, and 0.78 g·100g−1 DW, respectively) than from the open field (0.48, 0.29, and 0.59g·100g−1 DW, respectively). In turn, the dominant compound of the essential oil, i.e., linalool, was present in higher amounts in the essential oil obtained from plants cultivated in the open field. The sensory and microbiological quality of herb was comparable for both methods of cultivation. The obtained results indicate that, in central European climatic conditions, in organic cultivation, it is possible to obtain good-quality yield of basil herb. However, for its better productivity, it seems that cultivation under foil tunnels is preferable.
We have aimed to investigate the expression of genes related to rosmarinic acid (RA) synthesis and rosmarinic acid content in 2 Ocimum basilicum cultivars, green (cinnamon) and purple (red rubin) basil. Specifically, genes related to rosmarinic acid biosynthesis were cloned and characterized for O. basilicum. We obtained partial cDNAs of tyrosine aminotransferase (TAT) and 4-hydroxyphenylpyruvate reductase (HPPR), which were of 323bp and 616 bp in size, respectively. The transcription levels of most genes related to rosmarinic acid synthesis were higher in green basil compared to purple basil, except for ObPAL and Ob4CL in the root. The highest expression was obtained in the leaves of green basil for all genes and the roots of purple basil for all genes, except for TAT. The highest rosmarinic acid content was obtained in the leaves of both cultivars, with higher RA accumulating in green basil compared to purple basil. The leaves had the highest RA content out of all plant organs, with the RA accumulation in the leaves of green basil being 1.64 times higher compared to purple basil. Further study is required to investigate whether a similar trend is observed across O. basilicum cultivars of different color types.
Abstract
The aim of this review was to represent a category of applied plant biostimulants and to
highlight the effect of their application on morphological and phytochemical properties of
medicinal plants in in vivo and in vitro conditions and their mechanism of action. Plant
biostimulants, safe for both human beings and the environment, are substances or materials,
except for nutrients and pesticides, which have the ability to beneficially modify plant growth and
have been accepted over the past decade. Plant biostimulants have natural and synthetic origin.
The natural biostimulants contain amino acids, bacteria, seaweed, yeast, chitosan,
phytohormones, and also plant growth regulators (synthetic hormones), phenolic compounds,
inorganic salts, essential elements, and other different substances are some examples of synthetic
biostimulants. The plant biostimulants through different mechanisms of action (such as nitrogen
assimilation) are sustainable management practice for production of medicinal plants, increasing
biomass production, and enhancing secondary metabolites synthesis and it is investigated and
shown in many studies in recent years. Furthermore, there are many reports on positive effects of
biostimulants and elicitors application on medicinal plants in in vitro culture condition. Some
products of companies active in the formulation of biostimulants in Iran are mentioned in this
review. In conclusion, yield response in medicinal plants to biostimulants application showed that
each medicinal plant responds in a different way based on the chemical composition and
components of biostimulants, the timing and rate of application.
Keywords: Biostimulants, Elicitors, Medicinal Plants, Plant growth regulators, Secondary
metabolites
Sweet basil (Ocimum basilicum) is a warm-season herbaceous plant typically propagated from seed. Establishment of direct-seeded basil is oen difficult because seed germination may be limited, particularly in cold soils. To determine base, optimum, and ceiling germination temperatures and possible genetic variation, seeds of six cultivars of sweet basil, Italian Large Leaf, Italian Large Leaf 63-X, Nufar, Genovese, Genovese Compact Improved, and Aroma 2 were tested on a one dimensional thermogradient table from 0–45 °C. e average optimum germination temperature range was 34.5– 39.0 °C and did not differ among cultivars. Germination rates increased from about 0.05 seeds d − 1 near the base temperature to nearly 1.0 seeds d − 1 at optimum temperatures for most cultivars. e ceiling temperatures varied little among cultivars, with an average of 43 ± 1.3 °C. e thermal times to germination averaged 29 °h for new crop seeds but were 40 °h for seeds of Italian Large Leaf 63-X stored for 5 y under ambient conditions. Italian Large Leaf 63-X seeds also exhibited lower vigor, germination, and ceiling temperature, compared with the new crop seeds. Base temperatures ranged among cultivars from 9.8–13.2 °C and were statistically significant, suggesting there is genetic variation that can be exploited to improve the low temperature germination performance of basil.
Stresses provoked by adverse living conditions are inherent to a changing environment (climate change and anthropogenic influence) and they are basic factors that limit plant development and yields. Agriculture always struggled with this problem. The survey of non-toxic, natural, active substances useful in protection, and stimulation of plants growing under suboptimal and even harmful conditions, as well as searching for the most effective methods for their application, will direct our activities toward sustainable development and harmony with nature. It seems highly probable that boosting natural plant defense strategies by applying biostimulators will help to solve an old problem of poor yield in plant cultivation, by provoking their better growth and development even under suboptimal environmental conditions. This work is a concise review of such substances and methods of their application to plants.
Sweet basil has been used as a medicinal plant. This study was carried out to describe detailed growth and chemical Investigation of sweet basil essential oil affected by chemical and biological fertilizations. The various fresh and dry weights of herb in general changed under the various NPK fertilization+biological fertilization levels. The highest fresh and dry weights of herb (g plant-1 and t ha-1) were recoded with NPK (75%)+biological fertilizers treatment during the second harvest with the values of 721.2,49.8 and 79.4,4.4, respectively. The highest essential oil contents (0.4%, 0.7 mL plant-1and 57.9 L ha-1) were recorded at NPK (75%)+biological fertilizers treatment during the first harvest compared with other treatments. The highest amount of linalool and estragole were resulted from the NPK (75%) and NPK (50%)+biological fertilization treatment with the values of 51.2,27.7; 48.2,24.1; 54.4,24.1% during first, second and third harvests, respectively. Essential oil constituents belong to two chemical main classes. Oxygenated Monoterpenes (OM) was the major one, the remaining fractions as Monoterpene Hydrocarbons (MH) formed the minor class. The highest amount of OM were obtained from NPK (75%)+biological fertilization treatment with the values of 89.1,87.7 and 90.3% during first, second and third harvests, respectively.
Background
Ocimum americanum var. pilosum is a chilling-sensitive, widely distributed plant that is consumed as a vegetable in central and southern China. To increase our understanding of cold stress responses in this species, we performed de novo transcriptome assembly for O. americanum var. pilosum and compared the transcriptomes of plants grown under normal and low temperatures.
Results
A total of 115,022,842 high quality, clean reads were obtained from four libraries (two replicates of control samples and two replicates of chilling-treated samples) and were used to perform de novo transcriptome assembly. After isoforms were considered, 42,816 unigenes were generated, 30,748 of which were similar to known proteins as determined by a BLASTx search (E-value < =1.0E-05) against NCBI non-redundant, Swiss-Prot, Gene Ontology, KEGG, and Cluster of COG databases. Comparative analysis of transcriptomes revealed that 5179 unigenes were differentially expressed (with at least 2-fold changes, FDR < 0.01) in chilling-treated samples, and that 2344 and 2835 unigenes were up- and down-regulated by chilling stress, respectively. Expression of the 10 most up-regulated and the five most down-regulated unigenes was validated by qRT-PCR. To increase our understanding of these differentially expressed unigenes, we performed Gene ontology and KEGG pathway enrichment analyses. The CBF-mediated transcriptional cascade, a well-known cold tolerance pathway, was reconstructed using our de novo assembled transcriptome.
Conclusion
Our study has generated a genome-wide transcript profile of O. americanum var. pilosum and a de novo assembled transcriptome, which can be used to characterize genes related to diverse biological processes. This is the first study to assess the cold-responsive transcriptome in an Ocimum species. Our results suggest that cold temperature significantly affects genes related to protein translation and cellular metabolism in this chilling sensitive species. Although most of the CBF pathway genes have orthologs in O. americanum var. pilosum, none of the identified cold responsive (COR) gene orthologs was induced by cold, which is consistent with the lack of cold tolerance in this plant.
Electronic supplementary material
The online version of this article (doi:10.1186/s12864-016-2507-7) contains supplementary material, which is available to authorized users.
A plant biostimulant is any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrients content. By extension, plant biostimulants also designate commercial products containing mixtures of such substances and/or microorganisms. The definition proposed by this article is supported by arguments related to the scientific knowledge about the nature, modes of action and types of effects of biostimulants on crop and horticultural plants. Furthermore, the proposed definition aims at contributing to the acceptance of biostimulants by future regulations, especially in the EU, drawing the lines between biostimulants and fertilisers, pesticides or biocontrol agents. Many biostimulants improve nutrition and they do so regardless of their nutrients contents. Biofertilisers, which we propose as a subcategory of biostimulants, increase nutrient use efficiency and open new routes of nutrients acquisition by plants. In this sense, microbial biostimulants include mycorrhizal and non-mycorrhizal fungi, bacterial endosymbionts (like Rhizobium) and Plant Growth-Promoting Rhizobacteria. Thus, microorganisms applied to plants can have a dual function of biocontrol agent and of biostimulant, and the claimed agricultural effect will be instrumental in their regulatory categorization. The present review gives an overview of the definition and concept of plant biostimulants, as well as the main categories. This paper will also briefly describe the legal and regulatory status of biostimulants, with a focus on the EU and the US, and outlines the drivers, opportunities and challenges of their market development.
Background: Basil (Ocimum basilicum L.), a member of the Lamiaceae family, has
traditionally been used as a medicinal plant in the treatment of headaches, coughs, diarrhea,
constipation, warts, worms, and kidney malfunctions.
Objective: To investigate the foliar application effects of bio-stimulators and bio-fertilizers on
morphological and phytochemical traits of basil (Ocimum basilicum L.).
Methods: Bio-stimulators in three commercial formulations of aminolforte, kadostim and
fosnutren (with concentration of 1.5 L.ha-1) through foliar application, and bio-fertilizers in three
commercial formulations of nitroxin, super-nitro plus and barvar II (with concentration of 0.5
L.ha-1) through seed inoculation were considered as two studied factors.
Results: The results showed that the interaction effect of bio-stimulators and bio - fertilizers was
significant (p<0.01) on all of studied parameters except of chlorophyll content (SPAD value). The
highest leaf fresh weight (25.47 g/plant) and leaf dry weight (6.48 g/plant) were obtained under
fosnutren and nitroxin treatment, also maximum leaf number (206.33) was recorded in
aminolforte and nitroxin treatment. The highest leaf area (1302.2 mm2/plant) was observed in
kadostim and nitroxin treatment. Also results showed that the highest content of essential oil
(0.43%) was obtained in aminolforte and nitroxin, methyl chavicol (37.13%) in fosnutren and
super-nitro plus, geranial (29.05%) and caryophylene (6.66%) in kadostim and nitroxin, and
carvacrol (31.60%) in fosnutren and nitroxin treated plants.
Conclusion: In general, the best treatment to improve growth and phytochemical traits of
Ocimum basilicum were kadostim×nitroxin and fosnutren×nitroxin.
Keywords: Ocimum basilicum L., Bio-fertilizers, Bio - stimulators, Essential Oil, Leaf traits
Some basil varieties are able to convert the phenylpropenes chavicol and eugenol to methylchavicol and methyleugenol, respectively. Chavicol O-methyltransferase (CVOMT) and eugenol O-methyltransferase (EOMT) cDNAs were isolated from the sweet basil variety EMX-1 using a biochemical genomics approach. These cDNAs encode proteins that are 90% identical to each other and very similar to several isoflavone O-methyltransferases such as IOMT, which catalyzes the 4′-O-methylation of 2,7,4′-trihydroxyisoflavanone. On the other hand, CVOMT1 and EOMT1 are related only distantly to (iso)eugenol OMT from Clarkia breweri, indicating that the eugenol O-methylating enzymes in basil and C. breweri evolved independently. Transcripts for CVOMT1 and EOMT1 were highly expressed in the peltate glandular trichomes on the surface of the young basil leaves. The CVOMT1 and EOMT1 cDNAs were expressed in Escherichia coli, and active proteins were produced. CVOMT1 catalyzed the O-methylation of chavicol, and EOMT1 also catalyzed the O-methylation of chavicol with equal efficiency to that of CVOMT1, but it was much more efficient in O-methylating eugenol. Molecular modeling, based on the crystal structure of IOMT, suggested that a single amino acid difference was responsible for the difference in substrate discrimination between CVOMT1 and EOMT1. This prediction was confirmed by site-directed mutagenesis, in which the appropriate mutants of CVOMT1 (F260S) and EOMT1 (S261F) were produced that exhibited the opposite substrate preference relative to the respective native enzyme.
Urban agriculture is growing worldwide with the growth of cities. Urban agriculture represents about 20 % of Cuban agriculture. In Cuba, urban agriculture is institutionalized and organized with ecological principles. For instance, local agriculture enhances food security and decreases the use of nonrenewable fertilizers. However, organic crop production in urban environments is challenging because of intensive plant nutrient requirements and disease incidence. Here, we tested an innovative technology based on plant growth promoters isolated from vermicompost and applied directly to lettuce leaves. We monitored plant metabolism by measuring the activities of nitrate reductase, an enzyme linked to N assimilation, and of phenylalanine ammonia lyase, an enzyme linked to plant defense. The experiment was conducted in the organic urban system in Guines, Cuba. We applied liquid humates at 10, 15, or 20 mg C L−1 once at the seedling stage and again 15 days after transplantation. Our results show that humates at 15 mg C L−1 shortened by 21 days the lettuce production cycle, allowing early harvesting without changing quality while increasing yields expressed as the number of leaves per plant. Humate application also decreased total carbohydrate, increased protein, increased nitrate uptake, and stimulated nitrate reductase and phenylalanine ammonia lyase in lettuce leaves.
Sweet basil (Ocimum basilicum) is a popular culinary herbal crop grown for fresh or dry leaf, essential oil and seed markets. Recently, basil was shown to rank highest among species and herbal crops for phenolic compounds, essential oils which are associated with decreasing risks of cancer and aging diseases. The current study aimed to evaluate the potential activity of phenolic, flavonoids and essential oil of basil as antioxidant and anticancer activities by application organic and bio-organic fertilization. A pot experiment was conducted. Basil seeds were grown, with three levels of organic fertilizers (compost) in presence or absence of biofertilizer. Growth parameters, pigments content, total phenolics, total flavonoids and antioxidant activity of methanolic plant extract were examined. Application of 50% compost and 50% sand in the presence of biofertilizer resulted in enhancement fresh and dry weights, total phenolics, total flavonoids and pigment content as compared with compost alone. The constituents of essential oils extracted by hydrodistilation of basil leaves were identified by GLC. Eleven components of essential oils were identified. The highest value of antioxidant and anticancer activities were obtained in basil plants grown in 50% and 75% compost treatments in the presence of biofertilizer. These results emphasized the important of bioorganic fertilizers for enhancement the antioxidant activity of phenolics, flavonoids and essential oils of basil plant extract.
The genus Ocimum contains 35 aromatic species of annual, perennial, and shrub. Basil essential oil has a pleasant scent that both energizes and purifies the environment. It is consumed worldwide because of its anti-oxidant and anti-aging properties. The study aimed to find superior hybrids of the basil that produced high amounts of essential oil of better quality. It estimated heterosis while also combining ability, path, and other genetic parameters. We examined basil's general and special combining abilities and other genetic variables that determine yield, chemical makeup, and economic traits. The mean squares for variances in general and specific combining abilities (GCA and SCA) were significant for all thirteen traits, demonstrating that additive and non-additive genes influence these attributes. The hybrid L1 × T3 produced the highest essential oil (6.39 ml/plant), followed by L2 × T1 and L3 × T1 (5.13 ml/plant). The hybrid L1 × T2 and L5 × T1, with the most considerable SCA effect, produced better performances for the (-) linalool content (71.61% and 61.67%). The narrow-sense heri-tability for the eight characteristics under investigation ranged from 0.0038% to 62.95%. Narrow-sense heri-tability was moderate in terms of plant height and herb yields. It was high for branches/plant, essential oil yield, and camphor content (%). The genetic advance was also high in most characters, except for three traits: medium inflorescence length, and Chavibetol concentration. We investigated correlations between traits and contributions of the characters toward essential oil yield, as well as differential heterosis in hybrids for the stated variables , to gain a clear picture of the genetic advancement of the basil crop. With the exception of two traits-days to flowering and essential oil-the amplitude of SCA was greater than GCA variance, demonstrating the preponderance of non-additive gene action in the basil. The hybrids L1 × T1 followed by L1 × T3 and L2 × T1 were best for the essential oil yield of better quality. The L × T design is utilized for the first time and described in the Ocimum. These improved hybrids could be beneficial to large-scale farming.
Toll and interleukin-1 receptor (TIR) domain is a conserved immune module in prokaryotes and eukaryotes. Signaling regulated by TIR-only proteins or TIR domain-containing intracellular immune receptors is critical for plant immunity. Recent studies demonstrated that TIR domains function as enzymes encoding a variety of activities, which manifest different mechanisms for regulation of plant immunity. These enzymatic activities catalyze metabolism of NAD+, ATP and other nucleic acids, generating structurally diversified nucleotide metabolites. Signaling roles have been revealed for some TIR enzymatic products that can act as second messengers to induce plant immunity. Herein, we summarize our current knowledge about catalytic production of these nucleotide metabolites and their roles in plant immune signaling. We also highlight outstanding questions that are likely to be the focus of future investigations about TIR-produced signaling molecules.
Allergy is considered a hyperreactive immune response. Oligosaccharide ingredients are often incorporated in dietary supplements to modulate immunity, with oligosaccharides in ginseng thought to exert beneficial immunoregulatory effects. Here, efficacy and mechanism of action of ginseng oligosaccharide extract (GSO) for alleviating allergy were explored. GSO reduced secretion of β-HEX, HIS and inflammatory factor after C48/80 stimulation, while also reducing foot swelling and Evans blue exudation. Moreover, GSO treatment reduced PLCβ1 expression, intracellular calcium concentration, and calmodulin kinase (CaMK) phosphorylation that inhibited phosphorylation of PKC, leading to reduced MAPKs and p-c-Fos phosphorylation levels without affecting p-c-Jun levels. Notably, GSO inhibited allergy-like responses both in vivo and in vitro to reduce synthesis of inflammatory factors through the PKC/MAPK/c-Fos signaling pathway and inhibit PLC/Ca2+/CaMK pathway activity to reduce release of inflammatory factors and histamine and prevent allergy-associated degranulation effects. Thus, GSO holds promise as a clinical treatment for use in alleviating allergic disorders.
Ocimum sanctum L. is the most significant wellspring of medications utilized in the pharmaceutical industries and in the field of medicine. O. sanctum has a distinctive combination of pharmacological actions that support resilience and wellbeing. The secondary metabolites of O. sanctum show beneficial effects in the treatment of various diseases. This plant contains anti-oxidant properties and high amount of phenolic compounds which protect the body from toxin-induced damage. Due to its very high demand and less yield of the pharmaceutical content or secondary metabolites, there has been a persistent need to improve the productivity of the plant by using modern technology. There are various biotechnological methodologies which are utilized for the genetic improvement of this therapeutic plants viz micropropagation, direct or indirect in vitro regeneration, secondary metabolite enhancement by different types of elicitors, somatic embryogenesis and genetic transformation by various gene transfer approaches like Agrobacterium tumefiaciens, particle bombardment, etc. Genetic engineering for improvement of production of secondary metabolite and its biosynthesis pathways by overexpressing vital genes involved in the metabolite biosynthesis were reviewed. Omics techniques were also studied for understanding the genome structure, candidate genes and candidate proteins involved in secondary metabolites production. Overall, this review paper discusses the application of biotechnological techniques for enhancement of secondary metabolites production in O. sanctum.
Combining health-promoting nutrition with gastronomic novelty is a major trend currently driving the agri-food sector. Basil (Ocimum basilicum L.) is a genetically diverse aromatic vegetable crop that combines rich phytochemical composition and enticing sensory profile. The current review examines how genetic variation underlies the phytochemical composition, nutrient composition, and volatile aromatic compounds of basil. It further provides a critical assessment of preharvest factors that configure product quality, including nutrient modulation, controlled stress, biofortification, biostimulant and light management applications. Appropriate genotype selection may facilitate sustainable production of improved quality, whereas targeted preharvest applications combined with optimized light intensity and spectral quality may effectively increase the content of essential phytochemicals and micronutrients, while suppressing the accumulation of anti-nutritive agents. The application of biostimulants may further underpin the sustainability factor in basil production, especially under growth-limiting conditions. The current review constitutes a critical synopsis of all available scientific literature investigating key factors configuring the composition of basil in minerals, bioactive secondary metabolites, micronutrients and volatile aromatic compounds from 1996 to 2022. Topics warranting further research are highlighted, with emphasis placed in identifying optimal combinations within the genotype-environment-management interaction nexus that tap the physiological and molecular mechanisms responsible for improving plant performance and functional-sensory quality in basil.
LINK: https://authors.elsevier.com/a/1e-wU3AAyUFv1P
This review compiles the available information on potential sources and methodologies for the recovery of phenolic compounds from the residues (solid residue, wastewater or hydrolate) of the essential oil distillation of a total of 47 cultivated (native and exotic) or wild-collected aromatic plants of the Mediterranean region. Special attention has been paid to the new and promising techniques of distillation and processing of residues in the sense of a more efficient recovery of phenolic compounds with a reduced use of solvents and a time and energy saving. However, it has been observed that technique used for the distillation of the essential oil as well as the subsequent processing of the residue clearly affect the composition, and hence the biological properties, of the phenolic fraction. The most abundant compounds (42) were phenolic monoterpenes (thymol and carvacrol) and diterpenes (carnosic acid, carnosol and methyl carnosate), hydroxybenzoic acids (p-hydroxybenzoic, protocatechuic, vanillic, gallic, ellagic and catechol), phenylpropanoic acids (p-coumaric, caffeic, ferulic, rosmarinic chlorogenic, cryptochlorogenic and neochlorogenic), phenylpropenes (eugenol), coumarins (coumarin and herniarine), flavanones (naringenin, naringin, eriocitrin and hesperidin), flavones (apigenin, genkwanin, apigetrin, luteolin, cynaroside, luteolin 7-glucuronide, scolymoside, cirsimaritin and salvigenin) and flavanols (catechin, kaempferol methylethers, astragalin, quercetin, isoquercetin, hyperoside, miquelianin and rutin). The feasibility of recovering some of these phenolic fractions/compounds is discussed on the basis of the availability of the residue, the potential cost of the implementation by the industry, and in terms of sustainability like the use of less pollutant solvents as water or ethanol.
Plants cannot move, so they must endure abiotic stresses such as drought, salinity and extreme temperatures. These stressors greatly limit the distribution of plants, alter their growth and development, and reduce crop productivity. Recent progress in our understanding of the molecular mechanisms underlying the responses of plants to abiotic stresses emphasizes their multilevel nature; multiple processes are involved, including sensing, signalling, transcription, transcript processing, translation and post-translational protein modifications. This improved knowledge can be used to boost crop productivity and agricultural sustainability through genetic, chemical and microbial approaches.
Sweet basil (Ocimum basilicum L.), a wellknown medicinal and aromatic herb, rich in essential oils
and antioxidants (contributed by phenolics), is widely used
in traditional medicine. The biosynthesis of phytochemicals occurs via different biochemical pathways, and the
expression of selected genes encoding enzymes involved in
the formation of phenolic compounds is regulated in
response to environmental factors. The synthesis of the
compounds is closely interrelated: usually, the products
formed in the first reaction steps are used as substrates for
the next reactions. The current study attempted a comprehensive overview of the effect of aromatic amino acid
composition (AAAs) in Ocimum basilicum in respect to the
expression of genes related to the biosynthesis of phenolic
compound and their content. The transcript expression
levels of EOMT, PAL, CVOMT, HPPR, C4L, EGS, and
FLS increased depending on the AAAs concentration
compared to the control plants. The highest mRNA accumulation was obtained in EOMT, FLS, and HPPR in the
leaves of sweet basil. The expression of the TAT gene in
the leaves significantly reduced in response to all AAAs
applications compared to untreated groups and it had the
lowest transcript accumulation. Eleven individual phenolic
compounds were determined in the basil leaves, and the
contents of chicoric acid, methyl chavicol, caffeic acid, and
vanillic acid increased depending on administered concentration to control (p\ 0.05). Additionally, AAAs lead
to an incremental change in the amount of chlorogenic acid
at 50 and 100 mg kg-1 compared to control plants
(p\ 0.05). Rutin and rosmarinic acid were detected as the
main phenolic compounds in all experimental groups of
sweet basil in terms of quantity. However, their amount
significantly decreased as compared to control plants based
on the increase in AAAs concentrations (p\ 0.05). Also,
the accumulation of cinnamic acid, eugenol, and quercetin
did not significantly change in the leaves of AAAs treated
plants compared to control (p\ 0.05). When AAAs was
applied, total flavonoid content increased in all treatments
compared to the control plants, but total phenolic content
did not change significantly (p\ 0.05). To the best of our
knowledge, our work is the first detailed work to evaluate
in detail the impact of AAAs on individual phenolic
compounds at the phytochemistry and transcriptional levels
in the O. basilicum plant. For a detailed understanding of
the whole mechanism of phenolic compound regulation,
further research is required to fill in some gaps and to
provide further clarification.
Stress tolerance of the plant can be enhanced with the used of compounds that exhibit remarkable abilities to improve the growth without any side effects on plants and its environment. Many physiological and molecular activities in plants are controlled with those compounds. Of the medicinal and aromatic plants, sweet basil (Ocimum basilicum) possesses economic value due to their secondary metabolites such as essential oil and phenolic compounds. Along with the study, it was aimed to decrease the adverse impacts of the salinity stress from NaCl can be alleviated using priming with compounds. Herewith the study, salicylic acid, tryptophan and β-carotene were used for seed priming. Briefly, seeds of basil were soaked into 0.025 and 0.05 mM salicylic acid, 0.25 and 1 mM tryptophan and 0.1 and 0.2 mM β-carotene for 24 h. Following seed priming, when plants reached 5–6 leaf stage, the plants were exposed to salt stress (100 mM NaCl). In this context, plant growth parameters, photosynthetic pigments, essential oil components, total phenolic contents with their major fractions and DPPH activities of the plant leaves were screened. Results indicated that salinity decreased shoot and root length, root and leaf weight, leaf number, plant weight, and photosynthetic pigments of the plants. However, priming treatments partially alleviated the adverse effects of salinity on shoot and root length, root, leaf and plant weight, but had no significant effects on photosynthetic pigments in plants grown under saline conditions. Of the essential oil components, salinity reduced the percentage of linalool and eugenol but increased methyl eugenol percentage in non-primed plants. However, priming increased percentage of linalool and eugenol but decreased methyl eugenol percentage in plants grown under saline conditions. Regarding phenolics and individual fractions, salinity caused significant reductions in total phenolic, flavonoid contents, caffeic acid, chicoric acid, and rosmarinic acid content. Furthermore, DPPH activities of the extracts were also negatively affected by salinity. In addition, gas exchange parameters such as assimilation rate and stomatal conductance were affected negatively by salinity. Though, priming had a positive contribution to the gas exchange parameters under saline and non-saline conditions. As a result, it was observed that basil seedlings were negatively affected in terms of yield in 100 mM salt application, but especially 1 mM tryptophan priming could protect plants from the toxic effect of salt and increase the amount of individual phenolics under stress.
Basil (Ocimum basilicum L.), as an aromatic and medicinal plant, exhibits numerous of genotypes that have various applications in food and pharmaceutical industries. Thus, chemical composition is an important parameter for assessing the quality of basil. Hence, twelve European basil genotypes were cultivated under the same conditions, and isolated essential oils and methanol extracts were subjected to detailed chemical analyses and testing their biological activities. According to the analysis of the volatiles, all genotypes belong to linalool chemotype, and they were clustered into two groups. Rosmarinic acid was found to be the major phenylpropanoid, following with luteoin, kaempherol, and rutin. Principal component analysis of phenolic compounds indicated segregation of genotypes in two distinct groups. Biological activities of the isolated extracts were correlated with the concentrations of the actives, and it was found that naringenin, luteolin, and kaempherol are the main carriers of antioxidant activity, while the levels of linalool correlated with tyrosinase inhibition activity. Adversely, methyl chavicol showed negative correlations with both assays. Finally, it was found that Czech genotypes (Litra and Chladek), as well as Dutch (Bush) and Italian (Fino Verde Compatto) possess significant amounts of terpenoid linalool, together with flavonoids luteolin, naringenin, and kaempherol, and therefore, have strong biological activities required for their use in food and cosmetic industries.
In this study, antioxidant and antimicrobial activities of basil (Ocimum basilicum L.) essential oil (EO) in response to different Fe sources (Fe-arginine, Fe-glycine, and Fe-histidine nano-complexes and Fe-EDDHA) were examined. EO samples were predominantly constituted by the phenylpropanoid methyl chavicol (53-89.5%). Application of Fe nano-complexes significantly increased the occurrence and concentration of sesquiterpenes, while decreased the content of oxygenated monoterpenes. Antioxidant activity of basil EOs was evaluated using free radical 2,2-diphenyl-1-picrylhydrazyl, Nitric oxide, H2O2 and Thiobarbituric acid reactive substances scavenging assays, and in all assays the highest and the lowest activities were recorded in basils supplied with Fe-histidine nano-complex (1.02, 1.62, 2.21, 3.22 mg mL-1) and control (3.89, 4.89, 5.52, 6.79 mg mL-1), respectively. Fe-histidine nano-complex was the most effective treatment to inhibit fungal (C. albicans: 0.058 mg mL-1; A. niger: 0.066 mg mL-1), Gram-negative (E. coli: 0.181 mg mL-1; S. typhimurium: 0.163 mg mL-1) and Gram-positive (B. subtilis: 0.033 mg mL-1; S. aureus: 0.002 mg mL-1) growth. In conclusion, application of iron nano-complexes significantly altered biological and pharmacological characteristics of basil EOs. Our results are quite encouraging since EOs exhibited potent antioxidant effect and antimicrobial activities.
Sacred basil / Holy basil (Ocimum sanctum Linn) is a sacred plant widely used in pharmaceutical / cosmetic industries and is known for its varied medicinal properties. In order to study the influence of organic sources of nutrients on growth, yield and quality of sacred basil (Purple type), a field experiment was conducted at the ICAR-Directorate of Medicinal and Aromatic Plants Research, Boriavi, Anand, Gujarat for two consecutive seasons during 2015-2016. The experiment was devised in split plot design with three main plots (no organic/fallow, green manuring with cowpea (Vigna unguiculata (L.) Walp.) and crop residue of cluster bean (Cyamopsis tetragonoloba L. Taub) and seven sub plots (Control / no FYM (Farm yard manure), 50% N equivalent through FYM, 75% N equivalent through FYM, 100% N equivalent through FYM, 50% N equivalent through FYM + Arka Microbial consortia (AMC), 75% N equivalent through FYM + AMC and 100% N equivalent through FYM + AMC) in three replications. Results revealed that different plant growth parameters with respect to plant height, plant spread and number of branches and yield parameters such as dry herb yield, and essential oil content of pooled mean of two harvests (5.03 t ha−1, 1.35% and 6.79 kg ha−1, respectively) were recorded maximum in the treatment which received cluster bean crop residue. Among sub plot treatments, application of 100% N equivalent through FYM + AMC (N fixing, P & Zn solubilising and plant growth promoting microbes) recorded maximum dry herb yield (6.30 t ha−1), essential oil content (1.71%) and essential oil yield (10.79 kg ha−1) for the pooled mean of two harvests. Application of different crop residues significantly improved organic carbon (SOC) and available nutrient contents in soil, improved available nitrogen, phosphorus and potassium contents, soil microbial biomass (MBC) and dehydrogenase activity (DHA) compared with control. With these results, it can be concluded that incorporation of cluster bean crop residue prior to transplanting and application of 100% N equivalent through FYM + Arka microbial consortia could be recommended as organic production technology in sacred basil to obtain higher herbage yield and quality.
In response to the extremely large amounts of organic wastes currently produced, thermophilic composting technology has become increasingly popular for large-scale processing and disposal of a wide range of organic wastes. However, the process does not always produce high-quality products that have good potential for soil and land improvement, and most thermophilic composts do not have great economic value. Over the last 30 years, interest has increased progressively in the potential of a related process that involves the use of earthworms to break down organic wastes in a mesophilic process. In 1881, Charles Darwin first drew attention to the great importance of earthworms in the breakdown of dead plant organic materials and the release of the essential nutrients they contain in his book The Formation of Vegetable Mould through the Action of Worms. Many of his conclusions have been confirmed and utilized extensively during the last century (Edwards and Bohlen 1996). However, only in recent years has the considerable potential of using earthworms in systems of breaking down organic wastes to produce vermicomposts been explored in more depth to full commercial ventures (Edwards and Neuhauser 1988).
Here, for the first time, the accumulation ratio of methylchavicol and methyleugenoland compounds together with the expression profiles of five critical genes (i.e., 4Cl, C3H, COMT, CVOMT and EOMT) in three Iranian cultivars of basil were assessed under water deficit stress at flowering stage. The highest value of methylchavicol was detected for Cul. 3 under severe stress (S3; 7.695 μg/mg) alongside Cul. 2 under similar circumstances (S3; 4.133 μg/mg), while regarding Cul. 1, no detectable amounts were acquired. Considering methyleugenol, Cul. 3 (0.396 μg/mg; S0) followed by Cul. 1 (S3; 0.160 μg/mg) were the capable plant samples in producing some detectable amounts of methyleugenol. Apart from some expectations, all the genes under study exhibited also different transcription ratios under deficit stress. Our results, overall, demonstrated that the regulation of the above-mentioned genes and production of methychavicol and methyleugenol seems to be a cultivar- and drought stress-dependent mechanism.
Basil (Ocimum basilicum L.), a medicinal plant of the Lamiaceae family, is used in traditional medicine; its essential oil is a rich source of phenylpropanoids. Methylchavicol and methyleugenol are the most important constituents of basil essential oil. Drought stress is proposed to enhance the essential oil composition and expression levels of the genes involved in its biosynthesis. In the current investigation, an experiment based on a completely randomized design (CRD) with three replications was conducted in the greenhouse to study the effect of drought stress on the expression level of four genes involved in the phenylpropanoid biosynthesis pathway in O. basilicum c.v. Keshkeni luvelou. The genes studied were chavicol O-methyl transferase (CVOMT), eugenol O-methyl transferase (EOMT), cinnamate 4-hydroxylase (C4H), 4-coumarate coA ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). The effect of drought stress on the essential oil compounds and their relationship with the expression levels of the studied genes were also investigated. Plants were subjected to levels of 100%, 75%, and 50% of field capacity (FC) at the 6-8 leaf stage. Essential oil compounds were identified by gas chromatography/mass spectrometry (GC-MS) at flowering stage and the levels of gene expression were determind by real time PCR in plant leaves at the same stage. Results showed that drought stress increased the amount of methylchavicol, methyleugenol, ?-Myrcene and ?-bergamotene. The maximum amount of these compounds was observed at 50% FC. Real-time PCR analysis revealed that severe drought stress (50% FC) increased the expression level of CVOMT and EOMT by about 6.46 and 46.33 times, respectively, whereas those of CAD relatively remained unchanged. The expression level of 4CL and C4H reduced under drought stress conditions. Our results also demonstrated that changes in the expression levels of CVOMT and EOMT are significantly correlated with methylchavicol (r?=?0.94, P???0.05) and methyleugenol (r?=?0.98, P???0.05) content. Thus, drought stress probably increases the methylchavicol and methyleugenol content, in part, through increasing the expression levels of CVOMT and EOMT.
Humic acid rich vermicompost (HARV) was used to impart plant and soil health as compared to chemical fertilizers (CF), and normal vermicompost (NV) involving pea (Pisum sativum cv. Bonneville) as the host plant. The plant growth parameters of the crop were recorded at the time of harvesting and soil microbial structure was studied by using DGGE (Denaturing Gradient Gel Electrophoresis) on a temporal basis (0 day, 12th day, 30th day and 60th day). The growth parameters showed an increase of 34.04%, 50.61% and 33.12% in total height, fresh weight, and dry weight as compared to conventional chemical fertilizers (CF) and 25.53%, 70.13% and 59.49% as compared to control. The DGGE profiles revealed that maximum bacterial and fungal diversity and density occur in soil supplemented with HARV on 12th day (both Shannon’s index and Margalef’s index showed highest bacterial diversity (2.87) and richness (5.52) and highest fungal diversity (2.76) and richness (4.96)). The lowest values for the indices (Margalef’s and Shannon for bacteria 2.51 and 1.78 and Margalef’s and Shannon for fungi 2.12 and 1.43 respectively) were observed in CF applied soils on the 60th day where diversity was even lower than in case of control soil indicating the negative impacts of chemical fertilizers on soil microbial diversities. Amendment of soil with organic fertilizers improved root nodulation and AMF colonization; the increment being higher in HARV. External application of AMF and Rhizobium further improved these parameters suggesting that AMF and Rhizobium act synergistically with HARV in improving plant growth and soil health.
Isoprenoids and phenylpropanoids are the major secondary metabolite constituents in Ocimum genus. Though enzymes from phenylpropanoid pathway have been characterized from few plants, limited information exists on how they modulate levels of secondary metabolites. Here, we performed phenylpropanoid profiling in different tissues from five Ocimum species, which revealed significant variations in secondary metabolites including eugenol, eugenol methyl ether, estragole and methyl cinnamate levels. Expression analysis of eugenol synthase (EGS) gene showed higher transcript levels especially in young leaves and inflorescence; and were positively correlated with eugenol contents. Additionally, transcript levels of coniferyl alcohol acyl transferase, a key enzyme diverting pool of substrate to phenylpropanoids, were in accordance with their abundance in respective species. In particular, eugenol methyl transferase expression positively correlated with higher levels of eugenol methyl ether in Ocimum tenuiflorum. Further, EGSs were functionally characterized from four Ocimum species varying in their eugenol contents. Kinetic and expression analyses indicated, higher enzyme turnover and transcripts levels, in species accumulating more eugenol. Moreover, biochemical and bioinformatics studies demonstrated that coniferyl acetate was the preferred substrate over coumaryl acetate when used, individually or together in the enzyme assay. Overall, this study revealed the preliminary evidence for varied accumulation of eugenol and its abundance over chavicol in these Ocimum species. Current findings could potentially provide novel insights for metabolic modulations in medicinal plants.
The effect of elicitation with jasmonic acid (JA) on the plant yield, the production and composition of essential oils of lettuce leaf basil was evaluated. JA-elicitation slightly affected the yield of plants and significantly increased the amount of essential oils produced by basil – the highest oil yield (0.78 ± 0.005 mL/100 g dw) was achieved in plants elicited with 100 μM JA. The application of the tested elicitor also influenced the chemical composition of basil essential oils – 100 μM JA increased the linalool, eugenol, and limonene levels, while 1 μM JA caused the highest increase in the methyl eugenol content. Essential oils from JA-elicited basil (especially 1 μM and 100 μM) exhibited more effective antioxidant and anti-inflammatory potential; therefore, this inducer may be a very useful biochemical tool for improving production and composition of herbal essential oils.
Exposure to sustained low intensity microwaves can constitute a stress for the plants, but its effects on plant secondary chemistry are poorly known. We studied the influence of GSM and WLAN-frequency microwaves on emissions of volatile organic compounds and content of essential oil in the aromatic plant Ocimum basilicum L. hypothesizing that microwave exposure leads to enhanced emissions of stress volatiles and overall greater investment in secondary compounds. Compared to the control plants, microwave irradiation led to decreased emissions of β-pinene, α-phellandrene, bornyl acetate, β-myrcene, α-caryophyllene and benzaldehyde, but increased emissions of eucalyptol, estragole, caryophyllene oxide, and α-bergamotene. The highest increase in emission, 21 times greater compared to control, was observed for caryophyllene oxide. The irradiation resulted in increases in the essential oil content, except for the content of phytol which decreased by 41% in the case of GSM-frequency, and 82% in the case of WLAN-frequency microwave irradiation. The strongest increase in response to WLAN irradiation, >17 times greater, was observed for hexadecane and octane contents. Comparisons of volatile compositions by multivariate analyses demonstrated a clear separation of different irradiance treatments, and according to the changes in the volatile emissions, the WLAN-frequency irradiation represented a more severe stress than the GSM-frequency irradiation. Overall, these results demonstrating important modifications in the emission rates, essential oil content and composition indicate that microwave irradiation influences the quality of herbage of this economically important spice plant.
With respect to the adverse effects of chemical fertilizers on the environment and their higher cost, an alternative method of improving soil fertility has been tested. Application of vermicompost (VC) (produced from de-oiled waste) along with efficient bioinoculants (nitrogen fixer: Bacillus sp., JN700924; phosphate solubilizer: Bacillus megaterium, ATCC 14581; plant growth promoter: Pseudomonas monteilii, HQ 995498; arbuscular mycorrhizal fungus (AMF): Glomus intraradices) in different combinations were evaluated on Ocimum basilicum. VC along with bioinoculants treated plots showed a significant improvement in biomass (15.1-56%), essential oil content (26.7-48.2%) and essential oil yield (44.7-108.4%) over control. The major constituent of essential oil (i.e. methyl chavicol) was significantly improved in T3 (VC + Bacillus sp.), T5 (VC + P. monteilii) and T6 (VC + G. intraradices) treated plants as compared to control (T1). Significant improvement in microbial counts, percent root colonization of AMF and alkaline phosphatase activity were recorded maximum in bioinoculants along with VC treated plots. Improvement in soil organic carbon (4.2-51.16%), NH4+-N (27.0-55.3%), NO3--N (--8 to 60.33%], available P (15.2-43.5%) and available K (0.4-20.8%) were found in VC along with bioinoculants treated plots. The diethylene triamine pentaacetic acid extractable Fe (109-154 mg kg-1 soil) was more influenced by VC along with bioinoculants than other micronutrients (Cu, Mn and Zn). The results suggest that an integrated use of vermicompost with bioinoculants improves soil health and essential oil yield of O. basilicum.
Phospholipases D (PLD) and C (PLC) hydrolyze the phosphodiesteric linkages of the head group of membrane phospholipids. PLDs and PLCs in plants occur in different forms: the calcium-dependent phospholipid binding domain-containing PLDs (C2-PLDs), the plekstrin homology and phox homology domain-containing PLDs (PX/PH-PLDs), phosphoinositide-specific PLC (PI-PLC), and non-specific PLC (NPC). They differ in structures, substrate selectivities, cofactor requirements, and/or reaction conditions. These enzymes and their reaction products, such as phosphatidic acid (PA), diacylglycerol (DAG), and inositol polyphosphates, play important, multifaceted roles in plant response to abiotic and biotic stresses. Here, we review biochemical properties, cellular effects, and physiological functions of PLDs and PLCs, particularly in the context of their roles in stress response along with advances made on the role of PA and DAG in cell signaling in plants. The mechanism of actions, including those common and distinguishable among different PLDs and PLCs, will also be discussed.
The second edition of Gas Chromatography and Mass Spectrometry: A Practical Guide follows the highly successful first edition by F.G. Kitson, B.S. Larsen, and C.N. McEwen (1996), which was designed as an indispensible resource for GC/MS practitioners regardless of whether they are a novice or well experienced. The Fundamentals section has been extensively reworked from the original edition to give more depth of an understanding of the techniques and science involved with GC/MS. Even with this expansion, the original brevity and simple didactic style has been retained. Information on chromatographic peak deconvolution has been added along with a more in-depth understanding of the use of mass spectral databases in the identification of unknowns. Since the last edition, a number of advances in GC inlet systems and sample introduction techniques have occurred, and they are included in the new edition. Other updates include a discussion on fast GC and options for combining GC detectors with mass spectrometry. The section regarding GC Conditions, Derivatization, and Mass Spectral Interpretation of Specific Compound Types has the same number of compound types as the original edition, but the information in each section has been expanded to not only explain some of the spectra but to also explain why certain fragmentations take place. The number of Appendices has been increased from 12 to 17. The Appendix on Atomic Masses and Isotope Abundances has been expanded to provide tools to aid in determination of elemental composition from isotope peak intensity ratios. An appendix with examples on "Steps to follow in the determination of elemental compositions based on isotope peak intensities" has been added. Appendices on whether to use GC/MS or LC/MS, third-party software for use in data analysis, list of information required in reporting GC/MS data, X+1 and X+2 peak relative intensities based on the number of atoms of carbon in an ion, and list of available EI mass spectral databases have been added. Others such as the ones on derivatization, isotope peak patterns for ions with Cl and/or Br, terms used in GC and in mass spectrometry, and tips on setting up, maintaining and troubleshooting a GC/MS system have all been expanded and updated.
Plants that contain high concentrations of the defense compounds of the phenylpropene class (eugenol, chavicol, and their derivatives) have been recognized since antiquity as important spices for human consumption (e.g. cloves) and have high economic value. Our understanding of the biosynthetic pathway that produces these compounds in the plant, however, has remained incomplete. Several lines of basil (Ocimum basilicum) produce volatile oils that contain essentially only one or two specific phenylpropene compounds. Like other members of the Lamiaceae, basil leaves possess on their surface two types of glandular trichomes, termed peltate and capitate glands. We demonstrate here that the volatile oil constituents eugenol and methylchavicol accumulate, respectively, in the peltate glands of basil lines SW (which produces essentially only eugenol) and EMX-1 (which produces essentially only methylchavicol). Assays for putative enzymes in the biosynthetic pathway leading to these phenylpropenes localized many of the corresponding enzyme activities almost exclusively to the peltate glands in leaves actively producing volatile oil. An analysis of an expressed sequence tag database from leaf peltate glands revealed that known genes for the phenylpropanoid pathway are expressed at very high levels in these structures, accounting for 13% of the total expressed sequence tags. An additional 14% of cDNAs encoded enzymes for the biosynthesis of S-adenosyl-methionine, an important substrate in the synthesis of many phenylpropenes. Thus, the peltate glands of basil appear to be highly specialized structures for the synthesis and storage of phenylpropenes, and serve as an excellent model system to study phenylpropene biosynthesis.
Phenylpropenes such as eugenol, isoeugenol, chavicol, and anethole are C6-C3 volatile compounds derived from phenylalanine by modification of its benzene ring and reduction of its propyl side chain, with the final reduction step catalyzed by a product-specific phenylpropene synthase. Recent advances in the biochemical and molecular analysis of phenylpropene synthases have improved our understanding of their evolution, structural properties, and reaction mechanism, providing insights into how plants produce and regulate the many types of phenylpropene volatiles. Since phenylpropenes are important in determining the flavor of foods and the quality of essential oils in cosmetics, the identification of the genes and enzymes responsible for the biosynthesis of phenylpropene volatiles has also provided us with tools to meet the challenge of improving plant aromas through genetic engineering.
Phenylalanine amonia-lyase (PAL) is one of the most important enzymes that plays a key role in regulation of phenylpropanoid production in plants. It catalyzes the first step of the phenylpropanoid pathway in which L-phenylalanine is deaminated to trans-cinnamic acid. This step is significant for metabolic engineering and hyper-expression of the major phenylpropanoid, methyl chavicol. We followed gene expression and activity of PAL in Ocimum basilicum L. at different stages of growth including seedling, beginning and middle of growth phase, budding stage and flowering, and their correlation with final concentration of phenylpropanoid compounds. The level of gene expression was monitored by semi quantitative RT-PCR and phenylpropanoid compounds were identified by gas chromatography/mass spectrometry (GC/MS). PAL activity was assayed using spectrophotometer. The results indicated that the level of gene expression and activity of PAL enzyme are altered during the plant development, where the highest expression and activity (0.851 μmol cinnamic acid/mg/min) was achieved at budding stage. In this experiment, changes of methylchvicol content were correlated to the transcription and activity of PAL enzyme.