Methyl jasmonate redirects the dynamics of carbohydrates and amino acids toward the lignans accumulation in Linum album cells.

Linum album accumulates lignans e.g., podophyllotoxin (PTOX) and 6-methoxy podophyllotoxin (6MPTOX). This study was aimed to figure out how different concentrations of MeJA (0, 50, 100, 150, and 200 µM) by affecting on free sugars and amino acids contents induce lignans accumulation in L. album cells. Results revealed that hydrogen peroxide (H2O2) content increased at 50µM, while it decreased at the high levels of MeJA (150 and 200 µM). Also, increasing trend of nitric oxide (NO) and lipid peroxidation levels peaked at 200 µM MeJA. An increased antioxidant enzymes activity was also observed in the treated cells. Moreover, an increase in rhamnose/xylose, glucose, and mannose was detected at 150 and 200 µM MeJA compared to the control. These compounds provide energy source and carbon skeleton for amino acids biosynthesis. Our results emphasized variations in amino acids levels in the presence of MeJA, where Phe level shifts along with synthesizing phenolics. Likewise, MeJA treatment switch on phenyl-ammonia lyase (PAL) and tyrosine-ammonia lyase (TAL) activities that regenerate phenolic compounds. Changes in phenolic acids (cinnamic, coumaric, caffeic, ferulic, and salicylic acid) and flavonoids (catechin, vitexin, myricetin, and kaempferol) were observed under MeJA treatment. Eventually, MeJA induced lignans production except for lariciresinol (LARI), so that the highest amounts of PTOX and 6MPTOX were analyzed at 50 µM, which were 4 and 5 time of control, respectively. Conclusively, it can be suggested that MeJA-induced oxidative status change redirects free sugars and amino acids toward the production of phenolic compounds especially lignans in L. album cells.

Exogenous melatonin induces phenolic compounds production in Linum album cells by altering nitric oxide and salicylic acid.

Melatonin is a pleiotropic molecule that can influence various aspects of plant performance. Recent studies have exhibited that it mediates plant defensive responses, probably through managing redox homeostasis. We tried to track the regulatory effects of melatonin on the antioxidant machinery of Linum album cell culture. To this, different concentrations of melatonin were applied, and the oxidative status of cells was investigated by measuring the levels of oxidative molecules and antioxidant agents. The results showed that H2O2 content did not change at the low melatonin levels, while it increased at the high concentrations. It can be correlated with the low melatonin dosages capacity to remove excessive amounts of H2O2, while the high melatonin dosages exhibit toxicity effects. In contrast, the NO enhancement occurred at 50 µM melatonin, proposing its role in triggering melatonin-induced defensive responses. The MDA results stated that NO led to oxidative stress in melatonin-treated cells at 50 µM melatonin. Antioxidant enzyme POD was activated by melatonin treatment, while SOD enzyme behaved reversely which can explain the changes in the H2O2 level. In addition, the analysis of the phenolics profile showed that the contents of phenolic acids, flavonoids, and lignans enhanced following an increase in PAL enzyme activity. The increased level of phenolic hormone SA can indicate that melatonin affects the defensive responses in L. album cells through a SA-dependent pathway. In general, it seems that melatonin, by modulating NO and SA levels, can induce the activity of antioxidant enzymes and the production of phenolics, especially lignans, in L. album cells.

Changes in phenolic compounds production as a defensive mechanism against hydrogen sulfide pollution in Scrophularia striata.

Increasing pollutants such as hydrogen sulfide (H2S) from industrial activities is an ecological challenge for plants, which seriously affects their health and productivity. Scrophularia striata is a plant endemic to Iran growing in the province of Ilam, wherein a gas refinery releases toxic agents such as H2S whose detrimental effects on the function and tolerability of medicinal plants in this region have yet to be elucidated. Thus, we initiated a hydroponic study into hormetic effect of sodium hydrogen sulfide (NaHS) concentrations (0, 3 and 7 mM) as H2S-donor at different time points on oxidative status and phenolic compounds, focusing more on phenylethanoid glycosides (PhGs) in S. striata. Our results indicated that hydrogen peroxide (H2O2) increased significantly at 3 mM NaHS after 48 h, while its peak at 7 mM occurred after 24 h. Nitric oxide (NO) level peaked at 3 mM and 7 mM after 24 h. Treatment with NaHS also resulted in a dose-dependent induction of phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) enzyme activities, phenolic acids production (cinnamic acid, coumaric acid, ferulic acid, caffeic acid and salicylic acid) and acteoside accumulation, ultimately leading to an increase in antioxidant capacity. Modulation of soluble sugars contents including glucose, mannose and rhamnose/xylose, occurred after the treatment with NaHS, likely increasing plant tolerance due to their biological activity and structural effects. Overall, our results suggest that dose-dependent accumulation of phenolics, notably acteoside, leads to an augmentation in antioxidant system to deal with H2S stress in S. striata.

Predicting range shifts of three endangered endemic plants of the Khorassan-Kopet Dagh floristic province under global change.

Endemic plants of the Khorassan-Kopet Dagh (KK) floristic province in northeastern Iran, southern Turkmenistan, and northwestern Afghanistan are often rare and range-restricted. Because of these ranges, plants in the KK are vulnerable to the effects of climate change. Species distribution modelling (SDM) can be used to assess the vulnerability of species under climate change. Here, we evaluated range size changes for three (critically) endangered endemic species that grow at various elevations (Nepeta binaloudensis, Phlomoides binaludensis, and Euphorbia ferdowsiana) using species distribution modelling. Using the HadGEM2-ES general circulation model and two Representative Concentration Pathways Scenarios (RCP 2.6 and RCP 8.5), we predicted potential current and future (2050 and 2070) suitable habitats for each species. The ensemble model of nine algorithms was used to perform this prediction. Our results indicate that while two of species investigated would benefit from range expansion in the future, P. binaludensis will experience range contraction. The range of E. ferdowsiana will remain limited to the Binalood mountains, but the other species will have suitable habitats in mountain ranges across the KK. Using management efforts (such as fencing) with a focus on providing elevational migration routes at local scales in the KK is necessary to conserve these species. Additionally, assisted migration among different mountains in the KK would be beneficial to conserve these plants. For E. ferdowsiana, genetic diversity storage employing seed banks and botanical garden preservation should be considered.

Physiological, biochemical, and molecular responses of Linum album to digested cell wall of Piriformospora indica.

Plants synthesize a variety of metabolites in response to biotic elicitors. To comprehend how the digested cell wall of Piriformospora indica affects the response of ROS burst, antioxidant enzymes, amino acids profiling, and phenylpropanoid compounds such as lignans, phenolic acids, and flavonoids in Linum album hairy roots; we accomplished a time-course analysis of metabolite production and enzyme activities in response to CDCW and evaluated the metabolic profiles. The results confirms that CDCW accelerates the H2O2 burst and increases SOD and GPX activity in hairy roots. The HPLC analysis of metabolic profiles shows that the H2O2 burst shifts the amino acids, especially Phe and Tyr, fluxes toward a pool of lignans, phenolic acids, and flavonoids through alterations in the behavior of the necessary enzymes of the phenylpropanoid pathway. CDCW changes PAL, CCR, CAD, and PLR gene expression and transiently induces PTOX and 6MPROX as the main-specific products of PAL and PLR genes expression. The production of phenolic acids (e.g., cinnamic, coumaric, caffeic, and salicylic acid) and flavonoids (e.g., catechin, diosmin, kaempferol, luteolin, naringenin, daidzein, and myricetin) show different behaviors in response to CDCW. In conclusion, our observations show that CDCW elicitation can generate H2O2 molecules in L. album hairy roots and consequently changes physiological, biochemical, and molecular responses such as antioxidant system and the specific active compounds such as lignans. Quantification of metabolic contents in response to CDCW suggests enzyme and non-enzyme defense mechanisms play a crucial role in L. album hairy root adaptation to CDCW. A summary revealed that the correlation between H2O2 generation and L. album hairy root defense system under CDCW. Increase of H2O2 generation led plant to response against oxidative conditions. SOD, and GPX modulated H2O2 content, Phe, and Tyr shifted to the phenylpropanoid compounds as a precursor of PAL and TAL enzyme, the predominant phenylpropanoid compounds controlled oxidative conditions, and the other amino acids responsible for amino acid synthesis and development stages.

Optimization of Callus Induction with Enhancing Production of Phenolic Compounds Production and Antioxidants Activity in Callus Cultures of Nepeta binaloudensis Jamzad (Lamiaceae).

BACKGROUND: World Health Organization (WHO) reported that more than 80% of people in the world use herbal traditional medicines nowadays. Many endemic medicinal plants, especially Nepeta species, are facing to extinction as a result of high harvesting, limited distribution, and habitat destruction.Tissue culture is a successful method for plant secondary metabolites production. Nepeta binaloudensis is a medicinal plant belonging to family Lamiaceae. OBJECTIVE: Our study was focused on devising an optimum procedure for callus induction and phenolic compounds production in N. binaloudensis. First, we are focused on finding suitable explants and media for callus induction. Then, subsequent experiments were conducted to find an optimal concentration of plant growth regulators (PGRs) and reduced- glutathione for maximum biomass production, and phenolic compounds production in calli. MATERIAL AND METHOD: In this study, the usage of whole plant grown in Hoagland nutrient solution, were used as a source of explants. Also, different media including, ½ MS, MS, and B5 and different combination of PGRs (NAA and BAP) were used for optimization of calli induction. RESULTS: Based on the results of the first experiment, leaf-originated explants, and macro half strength MS (½ MS) medium were used for the next experiments. The highest FW (Fresh Weight) and DW (Dry Weight) of calli were observed in ½ MS medium, supplemented with 2 µM/L reduced-glutathione, 2 mg.L-1 BAP, and 2 mg.L-1 NAA. The maximum amount of total phenolic, flavonoid, tannin contents and free-radical scavenger were observed in calli which were grown in ½ MS medium supplemented with 2 µM/L reduced-glutathione, 2 mg.L-1 BAP, and 2 mg.L-1 NAA. CONCLUSION: Our study finds the optimum condition for calli induction and phenolic compounds production in N. binaloudensis.