Low UV radiation influenced DNA methylation, gene regulation, cell proliferation, viability, and biochemical differentiation in the cell suspension cultures of Cannabis indica.

The effect of low artificial Ultraviolet (UV) on the DNA methylation remains controversial. This study addresses how differential photoperiods of UV radiation affect the biochemical and molecular behaviors of Cannabis indica cell suspension cultures. The cell suspensions were illuminated with the compact fluorescent lamps (CFL), emitting a combination of 10% UVB, 30% UVA, and the rest visible wavelengths for 0, 4, 8, and 16 h. The applied photoperiods influenced cell morphological characteristics. The 4 h photoperiod was the most effective treatment for improving biomass, growth index and cell viability percentage while these indices remained non-significant in the 16 h treatment. The methylation-sensitive amplified polymorphism (MASP) assay revealed that the UV radiation was epigenetically accompanied by DNA hypermethylation. The light-treated cells significantly displayed higher relative expression of the cannabidiolic| acid synthase (CBDAS) and delta9-tetrahydrocannabinolic acid synthase (THCAS) genes about 4-fold. The expression of the olivetolic acid cyclase (OAC) and olivetol synthase (OLS) genes exhibited an upward trend in response to the UV radiation. The light treatments also enhanced the proline content and protein concentration. The 4 h illumination was significantly capable of improving the cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) concentrations, in contrast with 16 h. By increasing the illumination exposure time, the activity of the phenylalanine ammonia-lyase (PAL) enzyme linearly upregulated. The highest amounts of the phenylpropanoid derivatives were observed in the cells cultured under the radiation for 4 h. Taken collective, artificial UV radiation can induce DNA methylation modifications and impact biochemical and molecular differentiation in the cell suspensions in a photoperiod-dependent manner.

Silicon nanoparticles (SiNPs) stimulated secondary metabolism and mitigated toxicity of salinity stress in basil (Ocimum basilicum) by modulating gene expression: a sustainable approach for crop protection.

The underlying mechanisms through which silicon oxide nanoparticles (SiNPs) can confer salinity resistance to plants are poorly understood. This study explored the efficacy of supplementing nutrient solution with SiNPs (20-30 nm; 10 mg kg-1 soil) to stimulate metabolism and alleviate the risks associated with salinity (0.73 g kg-1 soil) in basil seedlings. For this purpose, variations in photosynthetic indices, proline osmoprotectant, antioxidant markers, phenylpropanoid metabolism, and transcriptional behaviors of genes were investigated. SiNPs increased shoot fresh weight (38%) and mitigated the risk associated with the salinity stress by 14%. SiNPs alleviated the inhibitory effects of salinity on the total chlorophyll concentration by 15%. The highest increase (twofold) in proline content was recorded in the SiNP-treated seedlings grown under salinity. The nano-supplement enhanced the activity of enzymatic antioxidants, including peroxidase (2.5-fold) and catalase (4.7-fold). SiNPs induced the expression of gamma-cadinene synthase (CDS) and caffeic acid O-methyltransferase (COMT) genes by 6.5- and 18.3-fold, respectively. SiNPs upregulated the eugenol synthase (EGS1) and fenchol synthase (FES) genes by six- and nine-fold, respectively. Salinity transcriptionally downregulated the geraniol synthase (GES) gene, while this gene displayed an upward trend in response to SiNPs by eight-fold. The nano-supplement transcriptionally stimulated the R-linalool synthase (LIS) gene by 3.3-fold. The terpinolene synthase (TES) gene displayed a similar trend to that of the GES gene. The highest expression (25-fold) of the phenylalanine ammonia-lyase (PAL) gene was recorded in seedlings supplemented with SiNPs. The physiological and molecular assessments demonstrated that employing SiNPs is a sustainable strategy for improving plant primary/secondary metabolism and crop protection.

Methyl jasmonate conferred Arsenic tolerance in Thymus kotschyanus by DNA hypomethylation, stimulating terpenoid metabolism, and upregulating two cytochrome P450 monooxygenases.

Arsenic (As) is a highly cytotoxic element impairing normal cellular functions, and its bioremediation has become one of the environmental concerns. This study explored the molecular and physiological responses of thyme (Thymus kotschyanus) seedlings to incorporating As (0 and 10 mgl-1) and methyl jasmonate (MJ; 0 and 10 µM) into the culture medium. The MJ treatment reinforced root system and mitigated the As cytotoxicity risk. MJ contributed to hypomethylation, a potential adaptation mechanism for conferring the As tolerance. Two cytochrome P450 monooxygenases, including CYP71D178 and CYP71D180 genes, were upregulated in response to As and MJ. The MJ treatment contributed to up-regulation in the γ-terpinene synthase (TPS) gene, a marker gene in the terpenoid metabolism. The As presence reduced photosynthetic pigments (chlorophylls and carotenoids), while the MJ utilization alleviated the As toxicity. The MJ supplementation increased proline accumulation and soluble phenols. The application of MJ declined the toxicity sign of As on the concentration of proteins. The activities of peroxidase, catalase, and phenylalanine ammonia-lyase (PAL) enzymes displayed an upward trend in response to As and MJ treatments. Taken collective, MJ can confer the As tolerance by triggering DNA hypomethylation, regulating CYPs, and stimulating primary and secondary metabolism, especially terpenoid.

Carboxylic acid-functionalized multiwalled carbon nanotubes (COOH-MWCNTs) improved production of atropine in callus of Datura inoxia by influencing metabolism, gene regulation, and DNA cytosine methylation; an in vitro biological assessment.

Atropine is a well-known tropane alkaloid commonly employed in medicine class called anticholinergics. This study intends to address biochemical and molecular responses of Datura inoxia calluses to fortifying culture medium with carboxylic acid-functionalized multi-walled carbon nanotubes (COOH-MWCNTs). The application of MWCNTs influenced callogenesis performance and biomass in a dose-dependent manner. The MWCNT at 5 mgL-1 resulted in the highest biomass of calluses by 57%. While, MWCNTs at high concentrations were accompanied by cytotoxicity. On the other hand, MWCNTs at concentrations above 100 mgL-1 exhibited cytotoxicity, decreased callogenesis performance, and reduced Atropine biosynthesis. The MWCNTs increased the activity of phenylalanine ammonia-lyase (PAL) and catalase enzymes. The concentrations of proline and soluble phenols displayed upward trends in response to using MWCNTs. According to the HPLC assessment, enriching culture medium with MWCNTs at 5 mgL-1 elicited Atropine production in calluses by 64%. The quantitative PCR assessment referred to the upregulation in the transcription of the PAL gene. The expression of ornithine decarboxylase (ODC) and putrescine N-methyltransferase 1 (PMT) genes were also upregulated in calluses cultured in a medium supplemented with MWCNTs. Methylation Sensitive Amplification Polymorphism (MSAP) technique indicated that employing MWCNTs altered the DNA methylation profile, reflecting epigenetic modification. Overall, engineering plant cells with MWCNTs as a nano-elicitor can be suggested for large-scale synthesis of industrially-valuable secondary metabolites.

Corona discharge plasma stimulated production of atropine in callus of Datura inoxia by DNA hypomethylation and gene regulation: a novel technology for plant cell and tissue culture.

Few investigations have tested the practical use of cold plasma as a novel technology to meet the requirements in the plant cell and tissue culture field. To fill the knowledge gap, we intend to respond to the question of whether plasma priming influenced DNA ultrastructure and the production of atropine (a tropane alkaloid) in Datura inoxia. Calluses were treated with the corona discharge plasma at time durations ranging from 0 to 300 s. Significant increases (about 60%) in biomass were observed in the plasma-primed calluses. The plasma priming of calluses enhanced the accumulation of atropine about 2-fold. The plasma treatments increased proline concentrations and soluble phenols. The drastic increases in the activity of the phenylalanine ammonia-lyase (PAL) enzyme resulted from the applied treatments. Likewise, the plasma treatment of 180 s upregulated the expression of the PAL gene by 8-fold. Also, the expression of the ornithine decarboxylase (ODC) and tropinone reductase I (TR I) genes were stimulated by 4.3-fold and 3.2-fold, respectively, in response to the plasma treatment. The putrescine N-methyltransferase gene displayed a similar trend to that of TR I and ODC genes following the plasma priming. Methylation sensitive amplification polymorphism method was employed to explore the plasma-associated epigenetic changes in DNA ultrastructure. The molecular assessment referred to DNA hypomethylation, validating an epigenetic response. This biological assessment study validates the hypothesis that plasma priming of callus is an efficient, cost-effective, and eco-friendly tool to enhance callogenesis efficiency, elicit metabolism, affect gene regulation, and modify chromatin ultrastructure in D. inoxia.

Zinc oxide nanoparticles (ZnONPs) influenced seed development, grain quality, and remobilization by affecting the transcription of microRNA 171 (miR171), miR156, NAM, and SUT genes in wheat (Triticum aestivum): a biological advantage and risk assessment study.

Limited studies have been conducted on the role of microRNAs (miRs) and transcription factors in regulating plant cell responses to nanoparticles. This study attempted to address whether the foliar application of zinc oxide nanoparticles (ZnONPs; 0, 10, 25, and 50 mgL-1) can affect miRs, gene expression, and wheat grain quality. The seedlings were sprayed with ZnONPs (0, 10, 25, and 50 mgL-1) or bulk counterpart (BZnO) five times at 72 h intervals. The application of ZnONPs at 10 mgL-1 increased the number of spikelets and seed weight, while the nano-supplement at 50 mgL-1 was accompanied by severe restriction on developing spikes and grains. ZnONPs, in a dose-dependent manner, transcriptionally influenced miR156 and miR171. The expression of miR171 showed a similar trend to that of miR156. The ZnONPs at optimum concentration upregulated the NAM transcription factor and sucrose transporter (SUT) at transcriptional levels. However, the transcription of both NAM and SUT genes displayed a downward trend in response to the toxic dose of ZnONPs (50 mgL-1). Utilization of ZnONPs increased proline and total soluble phenolic content. Monitoring the accumulation of carbohydrates, including fructan, glucose, fructose, and sucrose, revealed that ZnONPs at 10 mgL-1 modified the source/sink communication and nutrient remobilization. The molecular and physiological data revealed that the expression of miR156 and miR171 is tightly linked to seed grain development, remobilization of carbohydrates, and genes involved in nutrient transportation. This study establishes a novel strategy for obtaining higher yields in crops. This biological risk assessment investigation also displays the potential hazard of applying ZnONPs at the flowering developmental phase.

Non-thermal plasma improved callogenesis performance and elicited the production of cannabinoids by modifying DNA methylome, expression of WRKY1 and ERF1B transcription factors, and expression of genes that contributed to the biosynthesis of cannabinoids.

The current decade has witnessed notable advancement towards the utilization of non-thermal (cold) plasma in multidisciplinary fields such as plant sciences. This study intends to validate whether cold plasma contributes to improving callogenesis performance and eliciting the production of cannabinoids in cannabis. The cannabis-derived calli were treated with plasma at different exposure times, including 0, 60, 120, and 180 s. The plasma priming improved the callogenesis performance and callus biomass by an average of 46.6%. The molecular assessment (MSAP method) validated how the plasma priming is epigenetically associated with variation in DNA methylome in the cannabis calli. The cold plasma treatments transcriptionally upregulated the expression of WRKY1 and ERF1B transcription factors by averages of 3.5- and 3.8-fold. The plasma treatment also stimulated the transcription of OLS, OAC, CBGAS, CBDAS, and THCAS genes involved in the biosynthesis of cannabinoids. The HPLC assessment proved the high potency of cold plasma to enhance the synthesis of cannabinoids, including Cannabigerol (CBG), Cannabidiol (CBD), and cannabinol (CBN). The plasma-primed calli contained higher concentrations of proteins (56%), proline (38%), and soluble phenols (40%). The activities of peroxidase and catalase enzymes showed a similar upward trend in response to the plasma. The profound increase in the concentrations of soluble sugars resulted from the plasma treatments. The plasma priming of calli contributed to the significant upregulation in the activity of the phenylalanine ammonia-lyase enzyme. This biological assessment study validates the high potency of plasma priming to elicit the biosynthesis of cannabinoids in cannabis calli.

Simulated microgravity contributed to modification of callogenesis performance and secondary metabolite production in CannabisIndica.

In vitro plant culture paves the way for meeting the industrial demand of pharmaceutically valuable secondary metabolites. This study intends to monitor how callus cells of Cannabis indica respond to the simulated microgravity (clinorotation; a Man-made technology). Callus initiation resulted from the culture of the leaf explant in a medium supplemented with kinetin (0.5 mgL-1) and 2, 4-D (2 mgL-1). Calli were treated with microgravity at three exposure times (0, 3, and 5 days). The microgravity treatments increased callus biomass about 2.5-fold. The clinorotation treatments transcriptionally induced the olivetolic acid cyclase (OAC) and olivetol synthase (OLS) genes about 6.2-fold. The tetrahydrocannabinolic acid synthase (THCAS) and cannabidiolic acid synthase (CBDAS) genes displayed a similar upward trend in response to microgravity. The applied treatments also stimulated the expression of the ethylene-responsive element-binding proteins (ERF1B) and WRKY1 transcription factors by an average of 7.6-fold. Moreover, the simulated microgravity triggered epigenetic modification in the DNA methylation profile. The HPLC-based assessment validated the high efficacy of the clinorotation treatments to increase the concentration of cannabinoids, including Cannabigerol (CBG) and Cannabidiol (CBD). However, the clinorotated calli contained a lower concentration of Tetrahydrocannabinol (THC) than the control group. The microgravity treatments increased concentrations of proline (79%), soluble sugars (61.3%), and proteins (21.4%) in calli. The biochemical assessment revealed that the clinorotation treatments slightly increased H2O2 concentration. The upregulation in the activities of peroxidase, catalase, and phenylalanine ammonia-lyase enzymes resulted from the microgravity treatments. Both HPLC and molecular assessments validated the significant efficacy of microgravity to enhance the production of cannabinoids.

The potential contribution of the WRKY53 transcription factor, gamma-aminobutyric acid (GABA) transaminase, and histone deacetylase in regulating growth, organogenesis, photosynthesis, and transcriptional responses of tomato to different light-emitting diodes (LEDs).

Impressive progress in developing light-emitting diodes (LEDs) offers a new dimension for meeting agricultural and biological expectations. The present study addresses how tomato (Solanum lycopersicum) seedlings respond to the different spectral qualities of LEDs (white, red, blue, and blue + red). The light treatments in a wavelength-dependent manner contributed to the variations in biomass accumulation, morphology, and organogenesis pattern. Light quality epigenetically contributed to the transcriptional regulation of the histone deacetylase (HDA3) gene. The expression of WRKY53 transcription factor and gamma-aminobutyric acid transaminase (GABA-TP1) genes displayed a similar upward trend in response to the blue wavelength. On the contrary, the sole red light downregulated the WRKY53 and GABA-TP1 genes. The blue irradiation was associated with the upregulation in the glycolate oxidase (GLO2) and ribulose-1,5-bisphosphate carboxylase­oxygenase large subunit (rbcL) genes, while the red wavelength down-regulated the GLO2 and rbcL genes. Moreover, rbcL statistically correlated with GLO2, referring to the balanced regulation of photorespiration and the Calvin cycle. The blue wavelengths were more capable of improving the concentrations of photosynthetic pigments and proline. The seedlings grown under the white LEDs displayed the maximum activity of the catalase enzyme. The cultivation of tomato seedlings under the blue lights enhanced the activities of the superoxide dismutase and ascorbate peroxidase enzymes. The light treatments were associated with the variation in the nutritional status of K+ and Ca2+ in both leaves and roots. The presented findings and inferences support the potential contribution of WRKY53, HDA3, and GABA signaling in modulating plant responses to light quality.

Cold plasma can alleviate cadmium stress by optimizing growth and yield of wheat (Triticum aestivum L.) through changes in physio-biochemical properties and fatty acid profile.

Cold plasma (CP) application has increasing interest due to its environmental-friendly, high efficient, and low cost aspects to mitigate deletion effects of heavy metals on plants. A pot experiment was carried out to evaluate the CP application on yield, physiological, and fatty acid profile of wheat (Triticum aestivum L.) in a completely randomized design (CRD) with five replicates. Cadmium (Cd) was applied at four levels (0, 50, 100, and 150 µM), and CP were used on germinated seeds at three levels (0, 60, and 120 s) in a hydroponic system. The results showed CP alleviated the Cd accumulation in roots, shoots, and grains. The significant reduction of grain yield (GY) and thousand grain yield (TGY) was observed in plants exposed to 100 and 150 µM compared with the control plants; however, CP improved GY and TGY particularly at severe Cd stress. The minimum chlorophyll (Chl) and relative water content (RWC) were observed in plants exposed in 100 µM Cd and non-CP treatments. Proline increased by Cd stress but decreased with CP in most treatments. Unlike proline, methionine showed significant reduction under Cd stress. The fatty acid profile of wheat represented that severe Cd stress decreased monounsaturated fatty acid (MUFA) but increased polyunsaturated fatty acid (PUFA). Heat map (HM) showed that GY and methionine were the most sensitive traits under treatments of Cd and CP. Totally, we suggest the use of 120 s of CP to mitigate Cd stress on wheat plants.

Synthesis and characterization of chitosan encapsulated zinc oxide (ZnO) nanocomposite and its biological assessment in pepper (Capsicum annuum) as an elicitor for in vitro tissue culture applications.

Nanotechnology paves the way for introducing nanoscale fertilizers, pesticides, and elicitors. This study intends to address the synthesis of chitosan/zinc oxide nanocomposite (CS-ZnONP) and its biological assessment in in-vitro conditions. The zinc oxide nanoparticles (ZnONPs) were successfully coated with the chitosan (CS) polymer through a cost-effective approach. Transmission electron microscopy and Fourier transform infrared spectroscopy assessments proved the surface capping of chitosan polymer on ZnONP. The nanocomposite was more capable of improving growth and biomass than the bare ZnONPs. The application of the nanocomposite increased the concentration of chlorophylls (51%), carotenoids (70%), proline (2-fold), and proteins (about 2-fold). The supplementation of culture medium with the nanomaterials upregulated enzymatic antioxidant biomarkers (catalase and peroxidase). The activity of the phenylalanine ammonia-lyase enzyme also displayed a similar significant upward trend in response to the nano-supplements. The CS-ZnONP treatment considerably enhanced the accumulation of alkaloids (60.5%) and soluble phenols (40%), implying stimulation in secondary metabolism. The micropropagation test revealed that the CS-ZnONP treatment improved the organogenesis performance. Overall, the nanocomposite can be considered a highly potent biocompatible elicitor.

Nitric oxide and selenium nanoparticles confer changes in growth, metabolism, antioxidant machinery, gene expression, and flowering in chicory (Cichorium intybus L.): potential benefits and risk assessment.

This experiment was conducted to provide a better insight into the plant responses to nitric oxide (NO) and selenium nanoparticle (nSe). Chicory seedlings were sprayed with nSe (0, 4, and 40 mg l-1), and/or NO (0 and 25 µM). NO and/or nSe4 improved shoot and root biomass by an average of 32%. The nSe40 adversely influenced shoot and root biomass (mean = 26%), exhibiting moderate toxicity partly relieved by NO. The nSe and NO treatments transcriptionally stimulated the dehydration response element B1A (DREB1A) gene (mean = 29.6-fold). At the transcriptional level, nSe4 or NO moderately upregulated phenylalanine ammonia-lyase (PAL) and hydroxycinnamoyl-CoA quinate transferase (HCT1) genes (mean = sevenfold). The nSe4 + NO, nSe40, and nSe40 + NO groups drastically induced the expression of PAL and HCT1 genes (mean = 30-fold). With a similar trend, hydroxycinnamoyl-CoA Quinate/shikimate hydroxycinnamoyl transferase (HQT1) gene was also upregulated in response to nSe and/or NO (mean = 25-fold). The activities of nitrate reductase and catalase enzymes were also induced in the nSe- and/or NO-treated seedlings. Likewise, the application of these supplements associated with an increase in ascorbate concentration (mean = 31.5%) reduced glutathione (mean = 35%). NO and/or nSe enhanced the PAL activity (mean = 36.4%) and soluble phenols (mean = 40%). The flowering was also influenced by the supplements in dose and compound dependent manner exhibiting the long-time responses. It appears that the nSe-triggered signaling can associate with a plethora of developmental, physiological, and molecular responses at least in part via the fundamental regulatory roles of transcription factors, like DREB1A as one the most significant genes for conferring tolerance in crops.

Comparative efficacy of selenate and selenium nanoparticles for improving growth, productivity, fruit quality, and postharvest longevity through modifying nutrition, metabolism, and gene expression in tomato; potential benefits and risk assessment.

This study attempted to address molecular, developmental, and physiological responses of tomato plants to foliar applications of selenium nanoparticles (nSe) at 0, 3, and 10 mgl-1 or corresponding doses of sodium selenate (BSe). The BSe/nSe treatment at 3 mgl-1 increased shoot and root biomass, while at 10 mgl-1 moderately reduced biomass accumulation. Foliar application of BSe/nSe, especially the latter, at the lower dose enhanced fruit production, and postharvest longevity, while at the higher dose induced moderate toxicity and restricted fruit production. In leaves, the BSe/nSe treatments transcriptionally upregulated miR172 (mean = 3.5-folds). The Se treatments stimulated the expression of the bZIP transcription factor (mean = 9.7-folds). Carotene isomerase (CRTISO) gene was transcriptionally induced in both leaves and fruits of the nSe-treated seedlings by an average of 5.5 folds. Both BSe or nSe at the higher concentration increased proline concentrations, H2O2 accumulation, and lipid peroxidation levels, suggesting oxidative stress and impaired membrane integrity. Both BSe or nSe treatments also led to the induction of enzymatic antioxidants (catalase and peroxidase), an increase in concentrations of ascorbate, non-protein thiols, and soluble phenols, as well as a rise in the activity of phenylalanine ammonia-lyase enzyme. Supplementation at 3 mgl-1 improved the concentration of mineral nutrients (Mg, Fe, and Zn) in fruits. The bioaccumulated Se contents in the nSe-treated plants were much higher than the corresponding concentration of selenate, implying a higher efficacy of the nanoform towards biofortification programs. Se at 10 mgl-1, especially in selenate form, reduced both size and density of pollen grains, indicating its potential toxicity at the higher doses. This study provides novel molecular and physiological insights into the nSe efficacy for improving plant productivity, fruit quality, and fruit post-harvest longevity.

Selenium nanoparticles induced variations in growth, morphology, anatomy, biochemistry, gene expression, and epigenetic DNA methylation in Capsicum annuum; an in vitro study.

This study aimed to explore whether supplementation of the culture medium with selenium nanoparticles (nSe) can influence growth, biochemistry, expression of transcription factors, and epigenetic DNA methylation in Capsicum annuum. The seeds were grown in hormone-free MS culture medium supplemented with nSe (0, 0.5, 1, 10, and 30 mgL-1) or corresponding doses of bulk type selenate (BSe). Incorporation of nSe into the medium caused variations in morphology and growth in a manner dependent on the dose and Se type. The low doses of nSe displayed growth-promoting effects, whereas nSe at 10 and 30 mgL-1 were associated with severe toxicity and abnormality in leaf and root development. MSAP analysis confirmed the substantial variation in cytosine DNA methylation in response to the toxic dose of nSe exhibiting epigenetic modification. The nSe toxicity was associated with DNA hyper-methylations. The nSe treatments transcriptionally upregulated the bZIP1 transcription factor by an average of 3.5 folds. With a similar trend, the upregulation (mean = 9.8 folds) in the expression of the WRKY1 transcription factor resulted from the nSe application. The nSe0.5 or nSe1 treatments resulted in a significant induction (mean = 48%) in nitrate reductase activity. A high dose of nSe led to an increase in proline concentration. The nSe treatments were also associated with modifications in activities of peroxidase and catalase enzymes. Besides, the nSe utilization increased the activity of phenylalanine ammonia-lyase enzyme (mean = 76%) and concentrations of soluble phenols (mean = 51%). The toxic dose of nSe also caused abnormalities in the structure of the stem apical meristem. The nSe toxicity was also associated with inhibition in the differentiation of xylem tissues. These findings provide novel insights into the nSe-associated molecular variations in conferring the modified growth, anatomy, and metabolism.

Multi-walled carbon nanotubes improved growth, anatomy, physiology, secondary metabolism, and callus performance in Catharanthus roseus: an in vitro study.

This study was conducted to monitor the physiological and molecular responses of Catharanthus roseus (rose periwinkle) to multi-walled carbon nanotube (MWCNT) incorporation into the culture medium. The seeds were grown on hormone-free MS medium supplemented with 0, 50, 100, and 150 mgL-1of MWCNT. The supplementations of culture medium with MWCNTs led to significant increases in plant growth indexes such as leaf width, leaf area, leaf fresh weight, root length, and total plant biomass). Slight increases were also observed in chlorophyll a (Chla), Chlb, and carotenoid contents (mean = 18.6%) in MWCNT-treated seedlings. Protein concentrations increased by an average of 34% relative to the control. The application of MWCNT resulted in twofold increases in the catalase and peroxidase activities. A similar trend was also observed in the phenylalanine ammonia lyase activities (by an average of 36.5%), soluble phenols (by 23%), and alkaloids (by 1.7-fold). Moreover, upregulations (mean = 37-fold) in the transcriptions of the DAT gene resulted from the MWCNT supplementations. Exposure to MWCNT improved cell sizes and xylem conducting tissue in treated seedlings. The applications of MWCNTs also stimulated the callus initiation and performance, implying their effects on proliferation and possible differentiation. This study has provided evidence of role MWCNT play in improving plant performance and production of pharmaceutical secondary metabolites.

Differential physiology and expression of phenylalanine ammonia lyase (PAL) and universal stress protein (USP) in the endangered species Astragalus fridae following seed priming with cold plasma and manipulation of culture medium with silica nanoparticles.

KEY MESSAGE: Seed priming with cold plasma in combination with manipulation of culture medium with silica nanoparticle provokes anatomical, physiological and molecular changes, thereby reinforcing the plant growth and protection. ABSTRACT: This study addressed responses of Astragalus fridae to seed priming with cold plasma (0.84 W/cm2; 0, 30, 60, and 90 s) and applications of SiO2 nanoparticle (nSi; 0, 5, 40, and 80 mgl-1) in culture medium (an in vitro study). FE-SEM confirmed nSi uptake and translocation. Bulk Si at high concentrations reduced biomass accumulation (mean = 45%), while nSi did not make significant differences. The growth-enhancing effects of plasma by 41.5% were promoted by the nSi supplementation and reached 71%. Plasma did not make significant changes in Chla, while led to the slightly higher (mean = 14%) Chlb. The presence of nSi at high doses caused slight reductions in Chlb (mean = 25%) which were mitigated by plasma. The plasma and/or nSi treatments modified activities of phenylalanine ammonia lyase (PAL) in both roots (mean = 32%) and leaves (mean = 44%). With a similar trend, both individual and combined treatments of plasma and nSi provoked inductions in peroxidase activities in roots and leaves. The simultaneous treatments of plasma and nSi had the highest expression rates of PAL gene. The individual treatments of plasma did not make a significant difference in the expression of universal stress protein (USP) gene, whereas the nSi-treated seedlings exhibited the higher expression rates of USP. Leaf thicknesses and development of the vascular system (xylem and phloem) were reinforced in response to plasma and nSi. The findings provide evidence on potential benefits and phytotoxicity of nSi and plasma which may be employed as a theoretical basis for possible exploitation.

Differential growth, nutrition, physiology, and gene expression in Melissa officinalis mediated by zinc oxide and elemental selenium nanoparticles.

Regarding the rapid progress in the production and consumption of nanobased products, this research considered the behavior of Melissa officinalis toward zinc oxide nanoparticles (nZnO), nanoelemental selenium (nSe), and bulk counterparts. Seedlings were irrigated with nutrient solution containing different doses of nZnO (0, 100, and 300 mg l-1) and/or nSe (0, 10, and 50 mg l-1). The supplements made changes in growth and morphological indexes in both shoot and roots. The mixed treatments of nSe10 and nZnO led to a drastic increase in biomass, activation of lateral buds, and stimulations in the development of lateral roots. However, the nSe50 reduced plants' growth (45.5%) and caused severe toxicity which was basically lower than the bulk. Furthermore, the nSe and nZnO improved K, Fe, and Zn concentrations in leaves and roots, except for seedlings exposed to nSe50 or BSe50. Moreover, the nSe and nZnO supplementations in a dose-dependent manner caused changes in leaf non-protein thiols (mean = 77%), leaf ascorbate content (mean = 65%), and soluble phenols in roots (mean = 28%) and leaves (mean = 61%). In addition, exposure to nZnO and/or nSe drastically induced the expression of rosmarinic acid synthase (RAS) and Hydroxy phenyl pyruvate reductase (HPPR) genes. Besides, the nSe, nZnO, or bulk counterparts influenced the activities of nitrate reductase in leaves and peroxidase in roots, depending on dose factor and compound form. The comparative physiological and molecular evidence on phytotoxicity and potential advantages of nSe, nZnO, and their bulk counterparts were served as a theoretical basis to be exploited in food, agricultural, and pharmaceutical industries.