Azolla filiculoides extract improved salt tolerance in wheat (Triticum aestivum L.) is associated with prompting osmostasis, antioxidant potential and stress-interrelated genes.

The growth and productivity of crop plants are negatively affected by salinity-induced ionic and oxidative stresses. This study aimed to provide insight into the interaction of NaCl-induced salinity with Azolla aqueous extract (AAE) regarding growth, antioxidant balance, and stress-responsive genes expression in wheat seedlings. In a pot experiment, wheat kernels were primed for 21 h with either deionized water or 0.1% AAE. Water-primed seedlings received either tap water, 250 mM NaCl, AAE spray, or AAE spray + NaCl. The AAE-primed seedlings received either tap water or 250 mM NaCl. Salinity lowered growth rate, chlorophyll level, and protein and amino acids pool. However, carotenoids, stress indicators (EL, MDA, and H2O2), osmomodulators (sugars, and proline), antioxidant enzymes (CAT, POD, APX, and PPO), and the expression of some stress-responsive genes (POD, PPO and PAL, PCS, and TLP) were significantly increased. However, administering AAE contributed to increased growth, balanced leaf pigments and assimilation efficacy, diminished stress indicators, rebalanced osmomodulators and antioxidant enzymes, and down-regulation of stress-induced genes in NaCl-stressed plants, with priming surpassing spray in most cases. In conclusion, AAE can be used as a green approach for sustaining regular growth and metabolism and remodelling the physio-chemical status of wheat seedlings thriving in salt-affected soils.

Upregulated synthesis and production of bioactive compounds in Lotus arabicus L. by in vitro feeding with dried powder of date palm seeds.

BACKGROUND: Plants are considered the primary source of many principal bioactive compounds that have been utilized in a wide range of applications including the pharmaceutical and biotechnological industries. Therefore, there is an imperative need to modulate the production of natural bioactive components. The present study aimed to determine the importance of dried and pulverized date palm seeds (DPS) as a natural elicitor for the synthesis of secondary metabolites in Lotus arabicus L. RESULTS: The presence of various antioxidant compounds, simple sugars, amino acids, fatty acids and reasonable mineral contents was distinct in the phytochemical characterization of DPS. The major components detected in DPS analysis were the 5-(hydroxymethyl) furfural and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyranone. The induced callus of L. arabicus (seven weeks old) was supplemented with DPS at different concentrations (0, 2, 4, 8 and 10 g/l) in culture media. Treatment with 8 g/l DPS induced the highest antioxidant capacity, ascorbic acid content and secondary metabolites (total phenolics and flavonoids) in the produced callus. Stress biomarkers (hydrogen peroxide and malondialdehyde) were found in the control ranges except at 10 g/l DPS. The expression patterns of key genes involoved in secondary metabolism modulation, such as phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), flavonol synthase (FLS) and deoxyxylulose phosphate reductoisomerase (DXR), were triggered after DPS treatments. Moreover, the quantitative profiling of phenolic and flavonoid compounds showed that supplementation with DPS, especially at 8 g/l, led to pronounced increases in most of the measured compounds. CONCLUSION: The marked upregulation of eliciting-responsive genes and overproduction of secondary metabolites provide molecular-based evidence for intensifying the principal pathways of phenylpropanoid, flavonoid and terpenoid biosynthesis. Overall, the present in vitro study highlights the stimulating capacity of DPS utilization to improve the bioactive components of L. arabicus at the physiological and molecular levels, enhancing its potential as a medicinal herb.

Impacts of ZnO as a nanofertilizer on fenugreek: some biochemical parameters and SCoT analysis.

BACKGROUND: Zinc oxide nanoparticles (ZnO NPs) can be considered as nanofertilizer providing zinc as an essential micronutrient for plant growth and production at specific safe dose, however, above this dose; ZnO NPs induce oxidative stress. The present research aimed to evaluate some physiological and molecular effects of ZnO NPs on Trigonella foenum-graecum (fenugreek) plant. RESULTS: The ZnO NPs were applied at five different concentrations (10, 20, 30, 40, and 50 mg/l) via soaking fenugreek seeds for 24 h. Fenugreek seedlings were harvested after 14 days for biomass and biochemical analyses. The results revealed that increasing ZnO NPs concentration led to a significant increase in all measured parameters until peaked at 30 mg/l; after that, a decline trend was detected. However, malondialdehyde (MDA) increased significantly just at higher concentrations of ZnO NPs (40 and 50 mg/l). In addition, genetic variation measure using start codon targeted (SCoT) markers revealed that ZnO NP treatments exhibited limited genetic variation. CONCLUSION: Results showed that treatment with ZnO NPs at 30 mg/l can improve biomass, bioactive compounds, and antioxidant activity of fenugreek seedlings, besides being safe for DNA. So, this concentration could be a decent nanofertilizer for fenugreek plant.

Influence of gamma radiation and phenylalanine on secondary metabolites in callus cultures of milk thistle (Silybum marianum L.).

BACKGROUND: A useful technique for growing large amounts of plant material is in vitro propagation of important medicinal plants. The present investigation deals with the enhancement of secondary metabolite production via elicitation using gamma (γ)-radiation and phenylalanine (Phe) precursor feeding in callus cultures of Silybum marianum L. RESULTS: Seeds were exposed to two doses of γ-radiation (25 and 50 Gy) and the calli derived from stem explants  obtained from seedlings of these radiated seeds were treated with different concentrations of Phe. The biosynthesis of phenols and flavonoids was evaluated. It was found that callus cultures derived from explants of the seeds exposed to 25 Gy γ-radiation and treated with 4 mg/l Phe accumulated the maximum phenolic content (34.27±0.02 mg/g d.wt.), while the highest flavonoid content (9.56±0.12 mg/g d.wt.) was found in callus cultures derived from explants of seeds radiated with 25 Gy γ-radiation and subjected to 1 mg/l Phe. Similarly, HPLC quantification revealed that the production of flavonoids was highly accumulated (1343.06 µg/mg d.wt.) in callus cultures from explants of seeds  exposed to 25 Gy γ-radiation and grown at 1 mg/l Phe compared to the other treatments. In addition, a total of 11 important flavonoids have been determined in all callus cultures, except for acacetin-7-O-rutinoside, which was not found in the callus culture of the control. CONCLUSIONS: These findings suggest that γ-radiation combined with Phe can improve the metabolism of S. marianum L. and could be used to produce such valuable metabolites on a commercial scale.